Water distillation apparatus, method and system

Abstract

To provide an improved vapor compression distillation system.SOLUTION: The distillation device comprising a raw fluid input and an evaporator 6060 in fluid communication therewith, the device further comprising a compressor 6064 having an impeller coupled to a motor, the compressor having a low pressure inlet for vapor from the evaporator and a high pressure outlet for compressed vapor, the device further comprising a temperature sensor 6066 monitoring the temperature of the vapor at the inlet, and a condenser 6076 in heat transfer relationship with a plurality of external surfaces of the evaporator and in fluid communication with the outlet of the compressor; The device further comprises a controller 6034 for adjusting the rotational speed of the impeller with an impeller motor command based on a calibrated motor speed for the distillation device, wherein the controller is configured to determine an adjusted motor speed for a next device use and overwrite the calibrated motor speed with the adjusted motor speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Provisional Application No. 63 / 001,025 (Docket No. AA222), entitled "Water Distillation Apparatus, Method and System," filed March 27, 2020, which is incorporated herein by reference in its entirety.

[0002] The present invention relates to water distillation, and more particularly to an apparatus, method, and system for steam distillation of water. [Background technology]

[0003] A reliable source of clean water is inaccessible to far too many people. For example, the Canadian International Development Agency reports that approximately 1.2 billion people lack access to safe drinking water. Published reports attribute millions of deaths annually, most of them children, to water-related diseases. Many water purification techniques are well known, including carbon filters, chlorination, pasteurization, and reverse osmosis. Many of these techniques are highly sensitive to variations in water quality and do not address a wide variety of common contaminants, such as bacteria, viruses, organic matter, arsenic, lead, mercury, and pesticides, that can be found in water supplies in developing regions and elsewhere. Some of these systems require the availability of supplies of consumables, such as filters and chemicals. Furthermore, some of these technologies are suitable only for large, centralized water systems, requiring both significant infrastructure and highly trained personnel. The ability to produce reliable clean water on a smaller, decentralized scale, regardless of source, without the need for consumables and constant maintenance, is highly desirable, especially in developing regions. Summary of the Invention [Problem to be solved by the invention]

[0004] The use of vapor compression distillation to purify water is well known and has the potential to address many of these problems. However, the scarce financial resources, limited technological assets, and low population densities that make the construction of large-scale centralized water systems unfeasible in many developing regions also limit the availability of sufficient, affordable, and reliable electricity to operate vapor compression distillation systems and hinder the ability to properly maintain such systems. In such situations, improved vapor compression distillation systems and related components may provide a solution, increasing efficiency and production capacity while reducing the required power budget for system operation and the amount of system maintenance required. [Means for solving the problem]

[0005] According to one embodiment of the present disclosure, a distillation device may include a raw fluid input. The distillation device may further include an evaporator in fluid communication with the raw fluid input. The distillation device may further include a compressor having an impeller coupled to a motor. The compressor may have a low-pressure inlet for vapor from the evaporator and a high-pressure outlet for vapor compressed by the compressor. The distillation device may further include at least one temperature sensor configured to monitor the temperature of the vapor in the inlet. The distillation device may further include a condenser in heat transfer relationship with multiple exterior surfaces of the evaporator and in fluid communication with the outlet of the compressor. The distillation device may further include at least one controller configured to adjust the rotational speed of the impeller in the distillate production state with an impeller motor command. The impeller motor command may be based on a calibrated motor speed for the distillation device. The controller may be configured to determine an adjusted motor speed and overwrite the calibrated motor speed with the adjusted motor speed for use the next time the distillation device is in the distillate production state.

[0006] In some embodiments, the adjustment of the calibrated motor speed to the adjusted motor speed may be limited by an adjustment limit. In some embodiments, the controller may be configured to calculate the adjusted motor speed based on a proportional gain and a difference between a sensed temperature from the at least one temperature sensor and a target inlet steam temperature. In some embodiments, the adjustment limit may be less than or equal to two times the gain. In some embodiments, the distillate production state may be a hot water production state. In some embodiments, the controller may be configured to calculate the adjusted motor speed based on a difference between the target inlet steam temperature and a sensed inlet steam temperature from the at least one temperature sensor. In some embodiments, the sensed inlet steam temperature may be the output of a filter applied to an output data signal of the at least one temperature sensor. In some embodiments, the output data signal of the at least one temperature sensor may be low-pass filtered to determine the sensed inlet steam temperature. In some embodiments, the controller may be configured to calculate the adjusted motor speed by applying a proportional gain to the difference to determine an adjustment value and adding the adjustment value to the calibrated motor speed. In some embodiments, the raw fluid input may include at least one raw fluid temperature sensor. In some embodiments, the controller may be further configured to modify the calibrated motor speed with compensation based on the sensed source temperature from the raw fluid temperature sensor. In some embodiments, the sensed source temperature may be the output of a filter applied to the output data signal of the at least one raw fluid temperature sensor. In some embodiments, the output data signal of the at least one raw fluid temperature sensor may be low-pass filtered to determine the sensed source temperature. In some embodiments, the controller may be configured to calculate the compensation based on a difference between the sensed source temperature and a stored source temperature measured when the distillation device was calibrated. In some embodiments, the controller may be configured to calculate the compensation by applying a proportional gain to the difference.

[0007] According to another embodiment of the present disclosure, a distillation device may include a raw fluid input. The distillation device may further include an evaporator in fluid communication with the raw fluid input. In some embodiments, the distillation device may further include a compressor having an impeller coupled to a motor. The compressor may have a low-pressure inlet for vapor from the evaporator and a high-pressure outlet for vapor compressed by the compressor. The distillation device may further include at least one temperature sensor configured to monitor the temperature of the vapor in the inlet. The distillation device may further include a condenser in heat transfer relationship with multiple exterior surfaces of the evaporator and in fluid communication with the outlet of the compressor. The distillation device may further include at least one controller configured to adjust the rotational speed of the impeller in the distillate production state with an impeller motor command. The impeller motor speed command may be based on a calibrated motor speed for the distillation device. The controller may be configured to modify the calibrated motor speed to a modified motor speed upon exiting the distillate production state for use when the distillation device is subsequently in the distillate production state.

[0008] In some embodiments, the adjustment of the calibrated motor speed to the modified motor speed may be limited by an adjustment limit. In some embodiments, the controller may be configured to calculate the modified motor speed based on a proportional gain and a difference between a sensed temperature from the at least one temperature sensor and a target inlet steam temperature. In some embodiments, the adjustment limit may be less than or equal to two times the gain. In some embodiments, the distillate production state may be a hot water production state. In some embodiments, the controller may be configured to calculate the modified motor speed based on a difference between a target inlet steam temperature and a sensed inlet steam temperature from the at least one temperature sensor. In some embodiments, the sensed inlet steam temperature may be the output of a filter applied to an output data signal of the at least one temperature sensor. In some embodiments, the output data signal of the at least one temperature sensor may be low-pass filtered to determine the sensed inlet steam temperature. In some embodiments, the controller may be configured to calculate the modified motor speed by applying a proportional gain to the difference to determine an adjustment value and adding the adjustment value to the calibrated motor speed. In some embodiments, the raw fluid input may include at least one raw fluid temperature sensor. In some embodiments, the controller may be further configured to modify the calibrated motor speed with compensation based on the sensed source temperature from the raw fluid temperature sensor. In some embodiments, the sensed source temperature may be the output of a filter applied to the output data signal of the at least one raw fluid temperature sensor. In some embodiments, the output data signal of the at least one raw fluid temperature sensor may be low-pass filtered to determine the sensed source temperature. In some embodiments, the controller may be configured to calculate the compensation based on a difference between the sensed source temperature and a stored source temperature measured when the distillation device was calibrated. In some embodiments, the controller may be configured to calculate the compensation by applying a proportional gain to the difference.

[0009] According to another embodiment of the present disclosure, a distillation device may include a raw fluid input. The distillation device may further include an evaporator in fluid communication with the raw fluid input. The distillation device may further include a compressor having an impeller coupled to a motor. The compressor may have a low-pressure inlet for vapor from the evaporator and a high-pressure outlet for vapor compressed by the compressor. The distillation device may further include at least one temperature sensor configured to monitor the temperature of the vapor in the inlet. The distillation device may further include a condenser in heat transfer relationship with multiple exterior surfaces of the evaporator and in fluid communication with the outlet of the compressor. The distillation device may further include at least one controller configured to adjust the rotational speed of the impeller during the distillate production state with an impeller motor command. The impeller motor command may be based on a predetermined ideal motor speed for the distillation device. The controller may be configured to modify the ideal motor speed to a modified motor speed for use the next time the distillation device is in the distillate production state when the controller determines that a set of predetermined preconditions has been met.

[0010] In some embodiments, the adjustment of the ideal motor speed to the corrected motor speed may be limited by an adjustment limit. In some embodiments, the controller may be configured to calculate the corrected motor speed based on a difference between a target inlet vapor temperature and a sensed inlet vapor temperature from at least one temperature sensor. In some embodiments, the output data signal of the at least one temperature sensor may be low-pass filtered to determine the sensed inlet vapor temperature. In some embodiments, the controller may be configured to calculate the corrected motor speed by applying a proportional gain to the difference to determine an adjustment value and adding the adjustment value to the calibrated motor speed. In some embodiments, the raw fluid input may include at least one raw fluid temperature sensor. In some embodiments, the controller may be further configured to modify the ideal motor speed with compensation based on the sensed source temperature from the raw fluid temperature sensor. In some embodiments, the controller may be configured to phase the compensation over time as the distillation device is transitioned to a distillate production state. In some embodiments, the sensed source temperature may be the output of a filter applied to the output data signal of the at least one raw fluid temperature sensor. In some embodiments, the output data signal of the at least one raw fluid temperature sensor may be low-pass filtered to determine a sensed source temperature. In some embodiments, the controller may be configured to calculate compensation based on a difference between the sensed source temperature and a stored source temperature measured when the distillation device was calibrated. In some embodiments, the controller may be configured to calculate the compensation by applying a proportional gain to the difference. In some embodiments, the controller may be further configured to increment a timer in the distillate production state. The controller may be configured to determine that a predetermined set of preconditions is met when the timer increments above a threshold and the distillate production state is terminated. In some embodiments, the ideal motor speed may be a calibrated motor speed determined at the time of manufacture. In some embodiments, the ideal motor speed may be based on a calibrated motor speed determined at the time of manufacture.In some embodiments, the ideal motor speed may be based on a calibrated motor speed determined at the time of manufacture and a past correction applied to the calibrated motor speed after the distillation device met prerequisite conditions during previous use.

[0011] According to one embodiment of the present disclosure, a method for adjusting a calibration setpoint for a compressor motor of a vapor compression distillation device may further include driving the compressor motor with a motor speed command based on the calibrated setpoint. The method may further include monitoring the temperature of a vapor stream within the distillation device with at least one temperature sensor. The method may further include comparing a sensed vapor stream temperature from the at least one temperature sensor to a vapor stream temperature target. The method may further include determining an adjustment to the calibration setpoint based on the comparison, an adjustment factor, and at least one limit. The method may further include overwriting the calibration setpoint with an adjusted setpoint calculated based on the adjustment.

[0012] In some embodiments, the calibrated set point may be a value determined by the manufacturer for the distillation device. In some embodiments, monitoring the temperature of the vapor stream may include monitoring the temperature of a low-pressure vapor stream upstream of the compressor. In some embodiments, monitoring the temperature of the vapor stream may include monitoring the temperature of the vapor stream at an inlet to the compressor. In some embodiments, the vapor stream temperature target may be between 105.5 and 110.5°C. In some embodiments, the vapor stream temperature target may be 108.5°C. In some embodiments, the method may further include filtering an output signal of the at least one temperature sensor to determine a sensed vapor stream temperature. In some embodiments, the method may further include low-pass filtering an output signal of the at least one temperature sensor with a low-pass filter to determine a sensed vapor stream temperature. In some embodiments, the low pass filter may have a filter time constant of at least one hour. In some embodiments, comparing the sensed steam flow temperature from the at least one temperature sensor to the steam flow temperature target may include determining a difference between the sensed steam flow temperature and the steam flow temperature target. In some embodiments, the adjustment factor may be a proportional gain, and determining an adjustment to the calibration set point based on the comparison, the adjustment factor, and the at least one limit includes applying the proportional gain to the difference. In some embodiments, the at least one limit may be a range of + / - 2 times the proportional gain. In some embodiments, the at least one limit may be a range, the range having boundaries defined as a multiple of the proportional gain. In some embodiments, the proportional gain may be 25 rpm.

[0013] According to another embodiment of the present disclosure, a distillation device may include a raw fluid input. The distillation device may further include at least one temperature sensor configured to monitor the temperature of the raw fluid in the raw fluid input. The distillation device may further include an evaporator in fluid communication with the raw input. The distillation device may further include a compressor having an impeller coupled to a motor. The compressor may have a low-pressure inlet for vapor from the evaporator and a high-pressure outlet for vapor compressed by the compressor. The distillation device may further include a condenser in heat transfer relationship with multiple exterior surfaces of the evaporator and in fluid communication with an outlet of the compressor. The distillation device may further include at least one controller configured to adjust the rotational speed of the impeller during a distillate production state with a motor speed command based on a calibrated motor speed for the distillation device and compensation based on a sensed temperature of the raw fluid from the at least one temperature sensor.

[0014] In some embodiments, the compensation may be calculated based on a difference between the sensed temperature and a stored source temperature measured when the distillation device was calibrated. In some embodiments, the compensation may be calculated based on the difference and a proportional gain applied to the difference. In some embodiments, the proportional gain may be 10 rpm per 1°C difference. In some embodiments, the controller may be configured to phase the compensation over time during a transition state preceding the distillate production state. In some embodiments, the controller may be configured to apply the compensation by modifying the motor speed command over time to reflect the compensation. In some embodiments, the sensed temperature of the source fluid may be the output of a filter applied to an output data signal of at least one temperature sensor. In some embodiments, the output data signal of the at least one temperature sensor may be low-pass filtered to determine the sensed temperature of the source fluid. In some embodiments, the output data signal may be low-pass filtered with a time constant of at least one hour to determine the sensed temperature of the source fluid. In some embodiments, the distillate production state may be a normal temperature water production state. In some embodiments, the distillate production state may be a hot water production state. In some embodiments, the controller may be configured to gradually implement compensation over time during a transition between a first water production state and a second water production state that produces a product at a higher temperature than the first state.

[0015] According to another embodiment of the present disclosure, a distillation device may include a raw fluid input. The distillation device may further include at least one temperature sensor configured to monitor the temperature of the raw fluid in the raw fluid input. The distillation device may further include an evaporator in fluid communication with the raw input. The distillation device may further include a compressor having an impeller coupled to a motor. The compressor may have a low-pressure inlet for vapor from the evaporator and a high-pressure outlet for vapor compressed by the compressor. The distillation device may further include a condenser in heat transfer relationship with multiple exterior surfaces of the evaporator and in fluid communication with an outlet of the compressor. The distillation device may further include at least one controller configured to adjust the rotational speed of the impeller during distillate production conditions with a motor speed command based on an ideal motor speed specific to the distillation device and compensation based on a sensed temperature of the raw fluid from at least one temperature sensor.

[0016] In some embodiments, the compensation may be calculated based on a difference between the sensed temperature and a stored source temperature measured during calibration of the distillation device at the time of manufacture. In some embodiments, the compensation may be calculated based on the difference and a proportional gain applied to the difference. In some embodiments, the proportional gain may be 10 rpm per 1°C difference. In some embodiments, the controller may be configured to gradually implement the compensation over time during a transition state preceding the distillate production state. In some embodiments, the controller may be configured to apply the compensation by modifying the motor speed command over time to reflect the compensation. In some embodiments, the sensed temperature of the source fluid may be the output of a filter applied to an output data signal of at least one temperature sensor. In some embodiments, the output data signal of the at least one temperature sensor may be low-pass filtered to determine the sensed temperature of the source fluid. In some embodiments, the output data signal may be low-pass filtered with a time constant of at least one hour to determine the sensed temperature of the source fluid. In some embodiments, the distillate production state may be a normal temperature water production state. In some embodiments, the distillate production state may be a hot water production state. In some embodiments, the ideal motor speed may be a calibrated motor speed determined at the time of manufacture. In some embodiments, the ideal motor speed may be based on a calibrated motor speed determined at the time of manufacture. In some embodiments, the ideal motor speed may be based on a calibrated motor speed determined at the time of manufacture and any previous corrections to the calibrated motor speed determined and applied by the controller during previous use.

[0017] According to another embodiment of the present disclosure, a method for adjusting a calibration setpoint for a compressor motor of a vapor compression distillation device may include driving the compressor motor with a motor speed command based on the calibrated setpoint. The method may further include monitoring the temperature of a raw water flow to the distillation device with at least one temperature sensor. The method may further include comparing a sensed source temperature from the at least one temperature sensor to a stored source temperature value. The method may further include determining an adjustment to the calibration setpoint based on the comparison and an adjustment factor. The method may further include changing the calibration setpoint to a source temperature-compensated setpoint calculated based on the adjustment.

[0018] In some embodiments, the calibrated set point may be a value determined by a manufacturer for the distillation device. In some embodiments, the stored source temperature may be a measured temperature of the raw water stream taken during calibration. In some embodiments, the method may further include filtering an output signal of the at least one temperature sensor to determine a sensed source temperature. In some embodiments, the method may further include low-pass filtering an output signal of the at least one temperature sensor with a low-pass filter to determine a sensed source temperature. In some embodiments, the low-pass filter may have a filter time constant of at least 2 hours. In some embodiments, comparing the sensed source temperature from the at least one temperature sensor with a stored source temperature value may include determining a difference between the sensed source temperature and the stored source temperature value. In some embodiments, the adjustment factor may be a proportional gain, and determining an adjustment to the calibrated set point based on the comparison and the adjustment factor may include applying the proportional gain to the difference. In some embodiments, the proportional gain may be 10 rpm per 1°C difference. In some embodiments, changing the calibration set point to the source temperature compensated set point may include changing the calibration set point over time based on the adjustment. In some embodiments, changing the calibration set point to the source temperature compensated set point may include modifying a motor speed command generated by a controller of the distillation device to apply the adjustment. In some embodiments, changing the calibration set point to the source temperature compensated set point may include implementing the adjustment in stages.

[0019] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the detailed description, the drawings, and the claims.

[0020] These and other aspects will become more apparent from the following detailed description of various embodiments of the present disclosure, taken in conjunction with reference to the following drawings. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is an exemplary schematic diagram of a water purification system. [Figure 2] FIG. 2 is another exemplary schematic diagram of a water purification system. [Figure 3] FIG. 2 is another exemplary schematic diagram of a water purification system having an external evaporator water level sensor. [Figure 3A] FIG. 10 is another exemplary schematic diagram of a water purification system having a bearing feed pump bypass. [Figure 4] FIG. 2 is another exemplary schematic diagram of a water purification system. [Figure 5] FIG. 2 is a diagram of an exemplary embodiment of the system shown in FIG. 1. [Figure 6-7] FIG. 2 is a view of portions of the system with the hot section housing of the system removed. [Figure 8] FIG. 1 is a diagram of an exemplary heat exchanger. [Figure 9] FIG. 9 is a cross-sectional view of a portion of the example heat exchanger 6008 of FIG. 8. [Figure 10] 1 is a cross-sectional view of an exemplary water filter filled with source fluid. [Figure 11] FIG. 2 is an exploded view of a portion of the clarifier. [Figure 12] FIG. 1 is a top view of a portion of the clarifier with a portion of the concentrate reservoir cut away. [Figure 13] FIG. 1 is a cross-sectional view of an exemplary concentrate storage tank. [Figure 14-15] FIG. 1 is a perspective view of an interior volume of an exemplary steam chest. [Figure 16] FIG. 2 is another cross-sectional view of an exemplary concentrate storage tank. [Figure 17] FIG. 1 is a perspective view of an exemplary clarifier, heat exchanger, and concentrate storage tank. [Figure 18] FIG. 1 is an exploded view of an exemplary steam chest and mist eliminator. [Figure 19-20] FIG. 1 is a diagram of an exemplary channel convolutor. [Figure 21] 1 is a diagram of an exemplary drip pan. [Figure 22]This is an exploded view of the drip tray and mist eliminator. [Figure 23] FIG. 2 is a view of an exemplary compressor exploded from an exemplary steam chest. [Figure 24] FIG. 1 is an exploded view of an exemplary compressor. [Figure 25] FIG. 2 is another exploded view of an exemplary compressor. [Figure 26] FIG. 1 is a top view of an exemplary compressor. [Figure 27-28] FIG. 27 is a cross-sectional view taken at a specified plane in FIG. 26. [Figure 29] FIG. 2 is another top view of an exemplary compressor. [Figure 30-31] 29A and 29B are cross-sectional views taken at the specified plane in FIG. [Figure 32] FIG. 1 is a diagram of an exemplary purifier with the steam chest, mist eliminator, and condenser inlet fittings exploded. [Figure 33] FIG. 2 is a perspective view of an exemplary condenser inlet including a window. [Figure 34] FIG. 1 is a cross-sectional view of an exemplary purifier showing high pressure steam within the purifier. [Figure 35] FIG. 10 is a perspective view of another exemplary condenser inlet. [Figure 36] FIG. 2 is a side view of an exemplary clarifier evaporator condenser with a portion of the product reservoir cut away. [Figure 37] FIG. 1 is a perspective view of an exemplary purifier including several vent channels. [Figure 38] FIG. 1 is a perspective view of an exemplary clarifier including several product flow paths. [Figure 39] FIG. 1 is a side view of an exemplary clarifier including several product flow paths. [Figure 40-41] FIG. 2 is a diagram of an exemplary sensing manifold. [Figure 42-43] FIG. 1 is a perspective view of an exemplary mixing barrel. [Figure 44] 1 is a side view of an exemplary clarifier with an exemplary support plate pivot axis for the clarifier exploded; FIG. [Figure 45]FIG. 1 is a side view of an exemplary purifier with fasteners connecting the first and second sections of the purifier removed. [Figure 46] FIG. 1 is a side view of an exemplary purifier with a fastener connecting the first and second sections of the purifier removed and the first section displaced from the second section along a displacement path. [Figure 47] FIG. 1 is a side view of an exemplary purifier with the fasteners connecting the first and second sections of the purifier removed, displacing the first section from the second section about an arcuate path defined by a pivot axis. [Figure 48] FIG. 4 is a front perspective view of an exemplary system similar to that shown in FIG. 3. [Figure 49] FIG. 49 is a rear perspective view of the exemplary system shown in FIG. 48. [Figure 50] FIG. 2 is a front perspective view of an exemplary system with a portion of the exemplary system housing removed. [Figure 51] FIG. 2 is a rear perspective view of the exemplary system with a portion of the exemplary system housing removed. [Figure 52] 1A-1C are perspective views of portions of an exemplary purifier including several raw fluid flow paths. [Figure 53] 1A-1C are perspective views of portions of an exemplary purifier including several raw fluid flow paths. [Figure 54] FIG. 2 is a side view of an exemplary source inlet manifold. [Figure 55] FIG. 2 is a side view of an exemplary product heat exchanger manifold. [Figure 56] FIG. 1 is a diagram of an exemplary heat exchanger. [Figure 56A] FIG. 57 is a cross-sectional view of a portion of the example heat exchanger 6008 of FIG. 56. [Figure 57] FIG. 1 is an isometric view of a terminator for an exemplary product heat exchanger. [Figures 57A-57C] FIG. 58 is a cross-sectional and exploded view of a terminator for the exemplary product heat exchanger of FIG. 57. [Figure 57D] FIG. 1 is an isometric view of a terminator for an exemplary concentrate heat exchanger. [Figure 57E] FIG. 57D is a cross-sectional view of the terminator of FIG. 57D. [Figure 58] FIG. 2 is a top view of an exemplary clarifier. [Figure 59] 59 is a cross-sectional view taken at the designated plane of FIG. 58 and extending through the product reservoir and product reservoir level sensor of the clarifier. [Figures 59A-59D] FIG. 1 is a diagram of an evaporator water level sensor. [Figure 60] FIG. 2 is an exploded view of an exemplary evaporator condenser of the purifier. [Figure 61] FIG. 2 is another exploded view of an exemplary evaporator condenser of the purifier. [Figure 62] FIG. 62 is an enlarged detail of the designated area of ​​FIG. 61. [Figure 63] 59 is a cross-sectional view taken at the designated plane of FIG. 58 and extending through the blowdown reservoir and blowdown reservoir water level sensor of the clarifier. [Figure 64] 1 is a view of portions of an exemplary purifier with a portion of the steam chest of the exemplary purifier cut away. [Figure 65] FIG. 65 is an enlarged detail of the designated area of ​​FIG. 64. [Figure 66] FIG. 2 is a cross-sectional view of an exemplary blowdown reservoir and blowdown level sensor. [Figure 67] 1 is a perspective view of portions of an exemplary clarifier including several blowdown passages; [Figure 68] FIG. 1 is an exploded view of an exemplary steam chest. [Figure 69] 1 is a diagram of an exemplary steam chest and compressor, with the compressor disassembled from the steam chest. [Figure 70] 1 is a diagram of an exemplary compressor and vapor chest, with the compressor exploded. [Figure 71] FIG. 1 is an exploded view of an exemplary compressor. [Figure 72] FIG. 2 is a top view of an exemplary compressor and vapor chest. [Figure 72A] FIG. 73 is a cross-sectional view taken at the designated plane of FIG. 72. [Figure 72B] FIG. 73 is a cross-sectional view taken at the designated plane of FIG. 72. [Figures 73A-74B] FIG. 1 illustrates an embodiment of a blower and motor. [Figure 75] FIG. 2 is a top view of an exemplary compressor and vapor chest. [Figure 76] FIG. 76 is a cross-sectional view taken at the designated plane of FIG. 75. [Figure 77] FIG. 76 is a cross-sectional view taken at the designated plane of FIG. 75. [Figure 78] 1 is an exploded view of an exemplary evaporator-condenser and vapor chest, with the vapor chest exploded from the evaporator-condenser. [Figure 79] 1 is a cross-sectional view of an exemplary clarifier, the cross-section extending through the midplane of the product reservoir and product reservoir level sensor of the exemplary clarifier. [Figure 80] 1A-1C are perspective views of portions of an exemplary purifier including several vent channels. [Figure 81] FIG. 1 is an exploded view of an exemplary mixing reservoir and blowdown heat exchanger manifold. [Figure 82] 1A-1C are perspective views of portions of an exemplary clarifier including several product flow paths. [Figure 83] FIG. 2 is an exploded view of an exemplary product heat exchanger manifold. [Figure 83A] FIG. 10 is an isometric view of a second exemplary product heat exchanger manifold. [Figure 83B] FIG. 83B is a cross-sectional view of the second exemplary product heat exchanger manifold of FIG. 83A. [Fig. 83C-83F] FIG. 83B shows the conductivity sensor of FIG. 83A. [Fig. 84A-B] 4 is a flow diagram detailing some state changes that may occur during operation of an exemplary system. [Figure 85] 10 is a flowchart illustrating some exemplary operations that may be used in the Integrity Check State. [Figure 86] 10 is a flowchart detailing some exemplary operations that may be used in the fill state of the system. [Figure 87] 1 is a flowchart detailing some exemplary operations that may be used during filling of a clarifier. [Figure 88] 10 is a flowchart detailing some exemplary operations that may be used in a heating state of the system. [Figure 89] 4 is a flowchart detailing some exemplary operations that may be used to flush the filters of the system. [Figure 90] 1 is a flowchart detailing some exemplary operations that may be used to dispense a water sample. [Figure 91] 1 is a flowchart detailing some exemplary operations that may be used to prepare a system for filter replacement. [Figure 92] 1 is a flowchart detailing some exemplary operations that may be used in a production-ready state of the system. [Figure 93] 10 is a flowchart detailing some exemplary operations that may be used in a production start-up state of the system. [Figure 94] 10 is a flowchart detailing some exemplary operations that may be used during the water production phase of the system. [Figure 95] 10 is a flowchart detailing some exemplary operations that may be used in a hot water production readiness state of the system. [Figure 96] 4 is a flowchart detailing some exemplary operations that may be used in the hot water production state of the system. [Figure 97] 10 is a flowchart detailing some exemplary operations that may be used in the hot water production state of the system when the system is in self-sanitizing mode. [Figure 98] 4 is a flowchart detailing some exemplary operations that may be used in the standby state of the system. [Figure 99] 4 is a flowchart detailing some exemplary operations that may be used to control the liquid level in a clarifier. [Figure 100] FIG. 1 is an exemplary product temperature control diagram. [Figure 101A-101B] FIG. 10 is another exemplary product temperature control diagram. [Figure 101C]FIG. 101C is an alternative temperature control diagram for a portion of the control diagram presented in FIG. 101B, in which both product and blowdown temperatures are controlled. [Figure 102] 1 is a flowchart detailing some example operations that may be used to determine the fill rate of a reservoir. [Figure 103] 10 is a flowchart detailing some example operations that may be used to update a fill factor determination with a fill factor estimate. [Figure 104] 4 is a flowchart detailing some exemplary operations that may be used to adjust a target blowdown rate value. [Figure 105A] 10 is a flowchart detailing some exemplary operations that may be used to adjust a source proportioning valve command. [Figure 105B] 10 is a flowchart detailing some exemplary operations that may be used to adjust a source proportioning valve command. [Figure 106A-106B] 10 is a flowchart detailing some exemplary operations that may be used to determine source proportioning valve commands. [Figure 107] 10 is a flowchart detailing some exemplary operations that may be used to divert product water. [Figure 108] 1 is a flowchart detailing some exemplary operations that may be used to monitor for errors during operation of a system. [Figure 109] 4 is a flowchart detailing some exemplary operations that may be used to control the liquid level in a clarifier. [Figure 110] 4 is a flowchart detailing some exemplary operations that may be used to control a compressor motor. [Figure 111] 10 is a flowchart detailing some exemplary operations that may be used to automatically calibrate a nominal motor speed value. [Figure 112] 10 is a flowchart illustrating some exemplary operations that may be used in auto-calibrating a motor speed setpoint. [Figure 113] 10 is a flowchart illustrating some exemplary operations that may be used in auto-calibrating a motor speed setpoint. [Figure 114] 10 is a flowchart illustrating some exemplary operations that may be used in auto-calibrating a motor speed setpoint. [Figure 115] 10 is a flowchart detailing some example operations that may be used to adjust an ideal motor speed set point. [Figure 116] 10 is a flowchart detailing some example operations that may be used to add compensation to an ideal motor speed set point based on source flow temperature. [Figure 116A] 10 is a flowchart detailing some example operations that may be used to adjust the motor speed set point based on the source flow temperature and the low pressure steam temperature. [Figure 117] 4 is a flowchart detailing some exemplary operations that may be used to control the liquid level in a clarifier. [Figure 118] 1 is a flowchart detailing some exemplary operations that may be used to monitor for errors during operation of a system. [Figure 119] FIG. 1 is an exemplary heater control diagram. [Figure 120] 10 is a flowchart detailing some exemplary operations that may be used to determine a feed forward command for a compressor motor controller. [Figure 121] 1 is a flowchart detailing some exemplary operations that may be used to monitor for errors during operation of a system. [Figure 122] FIG. 1 is a block diagram of a system including a bearing feed flow sensor. [Figure 123] 1 is a flowchart detailing some exemplary operations that may be used to monitor flow from a bearing feed pump. [Figure 124]10 is a flowchart detailing some exemplary operations that may be used to determine a product reservoir outlet valve command. [Figure 125] 10 is a flowchart detailing several exemplary operations that may be used to adjust the duty cycle of a product reservoir outlet valve based on data from a product level sensor and a product temperature sensor. [Figure 126] 10 is a flowchart detailing several exemplary operations that may be used to adjust the duty cycle of a product reservoir outlet valve based on data from a product level sensor. [Figure 127] 10 is a flowchart detailing several exemplary operations that may be used to adjust the duty cycle of a product reservoir outlet valve based on data from one or more product temperature sensors. [Figure 128] 1 is a flowchart illustrating some exemplary operations that may be used to determine the presence of an abnormal raw water temperature in a system. [Figure 129] 1 is a flowchart illustrating some exemplary operations that may be used to adjust the temperature set point of a process stream. [Figure 130] 4 is a flowchart detailing some exemplary operations that may be used to control an electronics cooling valve of a system. [Figure 131] 4 is a flowchart illustrating some example operations that may be used to control cooling of an electronics housing of a system. [Figure 132] 10 is a flowchart illustrating some exemplary operations that may be performed to control the temperature of the blowdown process stream output from a heat exchanger. DETAILED DESCRIPTION OF THE INVENTION

[0022] Like numbers in the various drawings indicate like elements.

[0023] FIG. 1 shows a schematic diagram of an exemplary water purification system 6000. The system 6000 can take water from a source 6002 and purify it to remove various contaminants, making it suitable for consumption at a point of use. The point of use in the exemplary diagram is a medical system 6004. The purified output of the system 6000 can, in some examples, be used as a component of a medical treatment fluid used by the medical system 6004. However, the system 6000 can also be used to provide water for drinking purposes or for other devices requiring water that meets specific quality standards. Medical systems 6004 that can be used with the purification system 6000 can include various dialysis systems. The medical system 6004 can be a system for mixing therapeutic agents, such as dialysate. The medical system 6004 can also administer dialysis (peritoneal or hemodialysis) treatment to a patient. In a specific example, the medical system 6004 may be a peritoneal dialysate mixing system, or may be a system as described in U.S. patent application Ser. No. 12 / 072,908, filed February 27, 2008, entitled "Hemodialysis Systems and Methods" (now U.S. Patent No. 8,246,826, issued August 21, 2012) (Attorney Reference No. F65), U.S. patent application Ser. No. 12 / 199,055, filed August 27, 2008, entitled "Enclosure for a Portable Hemodialysis System" (now U.S. Patent No. 8,393,690, issued March 12, 2013) (Attorney Reference No. G20), and ... March 29, 2019, entitled "Liquid Pumping Cassettes and Associated Pressure Distribution Manifold and Related The hemodialysis system may be a hemodialysis system such as that described in U.S. Patent Application No. Z35, entitled "Methods for Diagnosis and Treatment of Diabetic Nephropathy," each of which is incorporated herein by reference in its entirety.

[0024] Various systems, methods, and apparatus described in U.S. patent application Ser. No. 13 / 952,263, entitled "Water Vapor Distillation Apparatus, Method and System," filed July 26, 2013 (now U.S. Pat. No. 9,604,858, issued March 28, 2017) (Attorney Reference No. K95), which is incorporated herein by reference in its entirety, and U.S. patent application Ser. No. 10 / 713,617, entitled "Pressurized Vapor Cycle Liquid Distillation," filed November 13, 2003 (now U.S. Pat. No. 7,597,784, issued October 6, 2009) (Attorney Reference No. D91), which is incorporated herein by reference in its entirety, may be used with one or more embodiments of the water distillation apparatus, methods, and methods described herein. Accordingly, other embodiments are contemplated, some of which include one or more of the apparatus, systems, and methods described in the above-referenced documents.

[0025] As shown, water may travel from a source 6002 to at least one filter 6006. The source 6002 may be a source 6002 that meets U.S. EPA requirements for drinking water. The source 6002 may, for example, meet the requirements of the National Class 1 Drinking Water Code (40 CFR 141), which is incorporated herein by reference in its entirety. It should be noted that the present disclosure is not limited by any provisions set forth in Section 141.2 or other portions of the documents incorporated by reference above. In certain embodiments, the source or raw fluid storage tank 6002 may be a residential water line that supplies water from a municipal or private water supply. The at least one filter 6006 may be an activated carbon filter. Other filter types that remove anticipated undesirable components of the source 6002 water, such as chlorine and chloramines, may also be used. In some embodiments, two redundant filters 6006 may be included in the system 6000. From the at least one filter 6006, the water may proceed to one or more heat exchangers 6008A,B.

[0026] In this exemplary embodiment, a first heat exchanger 6008A and a second heat exchanger 6008B are shown. These heat exchangers 6008A, B may be counterflow heat exchangers. Fluid entering each heat exchanger 6008A, B may be in a heat exchange relationship with at least one process stream from the water purifier 6010 of the system 6000. While the at least one process stream in each heat exchanger 6008A, B may be a different process stream, the heat exchangers 6008A, B may each also convey at least one common process stream to each other. When multiple streams are conveyed through a single heat exchanger, the streams may be separated as described in connection with heat exchangers described herein. In certain embodiments, one heat exchanger 6008A may convey a purified or product process stream, and the other may convey all other process streams from the water purifier 6010 (blowdown, retentate, vented gases, volatiles, or other waste process streams). Such heat exchangers 6008A,B are sometimes referred to as the product heat exchanger and the blowdown heat exchanger, respectively.

[0027] One or more valves may be included to provide control over the proportion of filtered raw water flowing through one heat exchanger 6008A,B relative to the other. This allows the temperature of the water flowing from the at least one filter 6006 through each of the heat exchangers 6008A,B to be varied higher or lower. Similarly, it also allows the temperature of the process stream traveling through the heat exchangers 6008A,B to be varied higher or lower. In some embodiments, the total mass flow rate or total incoming fluid from the at least one filter 6006 through both heat exchangers 6008A,B may be generally constant or may be controlled by an otherwise unrelated control algorithm as the proportion of incoming fluid directed to each heat exchanger 6008A,B is manipulated. The total mass flow rate of fluid from the at least one filter 6006 through the heat exchangers 6008A,B may also vary in conjunction with this proportion.

[0028] From the heat exchangers 6008A,B, the filtered source streams recombine and enter the purifier 6010 for purification. The purifier 6010 can remove or reduce the concentration of at least one contaminant, and possibly multiple contaminants, in the source water. The water purifier 6010 can be any of the steam distillation devices described herein, although other distillation or water purification devices can be used. In the exemplary system 6000, the water purifier 6010 is capable of purifying the water to quality standards sufficient for use in the medical system 6004. The water may comply with quality standards issued, for example, by a governmental body, a standards organization, an NGO, or other applicable organization. If the medical system 6004 is a dialysis system, the standards may be, for example, standards found in the USP Water Specifications for Hemodialysis, which is incorporated herein by reference in its entirety (adding references to the specific standards).

[0029] The water clarifier 6010 may generate several process streams. The process streams may be fluid streams, including, but not limited to, a product water stream, a blowdown water stream, and a gaseous exhaust stream. Some of these streams may be held in process stream storage tanks after being generated by the water clarifier 6010. The exemplary illustration includes a product water storage tank 6012 and a blowdown storage tank 6014. These storage tanks 6012, 6014 may have internal volumes sized to hold a volume of fluid from their respective process streams. Each storage tank 6012, 6014 may also include a water level sensor to determine the volume of the respective process stream within each storage tank.

[0030] The process streams may exit the water clarifier 6010 or storage tanks 6012, 6014 and proceed to heat exchangers 6008A, B of the system 6000. As these streams pass through the heat exchangers 6008A, B, heat transfer may occur between the process streams and the raw water en route from the at least one filter 6006 to the clarifier 6010. Generally, the process stream may transfer heat to the raw water, thereby cooling the process stream and increasing the temperature of the raw water. When a gaseous process stream passes through the heat exchangers 6008A, B, the heat exchange may cause at least a portion of the gaseous process stream to condense.

[0031] As described above, the mass fraction of raw water passing through each heat exchanger may be varied. The mass fraction may be controlled, for example, to cause the temperature of the product stream to comply with a predetermined temperature range or threshold. This temperature requirement may be an acceptable operating temperature range or threshold for the medical system 6004. The medical system 6004 may accept water at temperatures below a certain threshold and / or within a certain range, and the mass fraction of the raw water stream may be controlled to ensure that the product stream complies with any such criteria. If the medical system 6004 is a hemodialysis system, the threshold may be around average human body temperature (e.g., 37°C + / - 5°C).

[0032] The system 6000 may further include at least one sensor assembly 6016. The at least one sensor assembly 6016 may monitor one or more characteristics of interest of one or more of the process streams. Possible characteristics of interest may include, but are not limited to, temperature, concentration of dissolved ions, conductivity, optical properties, turbidity, the presence of specific compounds or elements, and other water quality characteristics described elsewhere herein. In some specific embodiments, the sensor assembly 6016 may monitor the quality of the water exiting the first or product heat exchanger 6008A. For example, conductivity and temperature may be measured. Data from the at least one sensor assembly 6016 may provide feedback to a controller (e.g., P, PI, PID) that adjusts the mass fraction of raw water flowing through each heat exchanger 6008A,B. Additionally, data from the at least one sensor assembly 6016 may direct the operation of a diversion valve to allow the flow of product water to proceed to either the medical system 6004 or to a drain 6018 or disposal location. For example, if the conductivity of the product water is greater than a predetermined threshold, the diversion valve may be activated to divert the product water to the drain 6018 until the conductivity drops back to an acceptable level.

[0033] The drain 6018 may be used to receive excess product water, if any, produced by the water purifier 6010. If the medical system 6004 does not require water and the product storage tank 6012 is full, the product water may be diverted to the drain 6018. The drain 6018 may also receive other process streams from the water purifier 6010, such as a blowdown stream or any other waste stream. The drain 6018 may be to any suitable destination, such as a municipal sewer or the like.

[0034] Referring now to Figure 2, another representational block diagram of the example system 6000 of Figure 1 is shown. The example system 6000 includes a source check valve 6030 that allows one-way flow from the source 6002 to the remainder of the system 6000. In addition, a shut-off valve 6032 is included. This shut-off valve 6032 may be mechanical (e.g., a ball valve) or may be operated by a controller 6034. The shut-off valve 6032 may be activated to prevent source fluid from entering the system in the event of a fault condition or other undesirable situation. The example system 6000 also includes a pressure transducer 6036 in data communication with the controller 6034 that can sense the pressure of the incoming source water.

[0035] The exemplary system 6000 includes a first filter 6006A and a second filter 6006B. An additional coarse filter (not shown) to prevent the inflow of large sediments may be included upstream of the first filter 6006A and the second filter 6006B in some embodiments. The first filter and the second filter 6006A,B may be activated carbon filters (e.g., 5-6 L activated carbon filters). These filters 6006A,B may function as organic contaminant and / or oxidant removal elements and may remove chemicals such as chlorine, chloramines, and others from the raw water.

[0036] In certain implementations, the first and second filters 6006A, B may be substantially identical and redundant filters. The filters 6006A, B may be separated by a fluid flow path that includes an inspection or sampling port 6038. The sampling port 6038 allows a user to periodically (e.g., before each use or on some other predetermined schedule) withdraw fluid filtered through the first filter 6006A for manual inspection.

[0037] The sampling port 6038 may include a valve (e.g., a manually operated valve) that, when activated, allows a sample to be dispensed into a test vessel or the like. In some embodiments, the sampling port 6038 may include a push button that mechanically opens a flow path for water to travel through the sampling port 6038 for dispensing. The controller 6034 may receive a signal when the push button is pressed. In certain embodiments, the sampling valve may be controller-actuated and commanded to open by the controller 6034 when a button press signal is received by the controller 6034. The sampling port 6038 may be associated with a user interface, e.g., a graphical user interface, and the button may be a soft button displayed on a touch screen. In other embodiments, the user interface may be simple and may include one or more lights (e.g., LEDs) that convey status information (power, system status, sample ready, fault, etc.).

[0038] The manual testing may depend on the types of chemicals likely to be present in the source 6002 and may include chlorine-free and / or total chlorine testing. In alternative embodiments, a meter for sensing the expected chemical concentration (e.g., a chlorine meter) may be included instead of or in addition to the test port 6038. Such a meter may be in data communication with the controller 6034, which may analyze data generated via the meter. The test port 6038 and / or the meter may allow a user to determine when the filters 6006A, B need to be replaced. In some embodiments, the system 6000 may prevent operation of the water purifier 6010 until the controller 6034 receives a signal indicating acceptable filtration of the water exiting the first filter 6006A. Alternatively or additionally, the medical system 6004 may not accept water from the system 6000 unless a data signal indicating acceptable filtration from the first filter 6006A is received. If the test is performed manually, the signal may be generated via user input to a user interface of the system 6000 or via user input to a user interface of the medical system 6004. The signal may also be generated by a test meter.

[0039] After passing through the second filter 6006B, the filtered raw water may enter a valve manifold 6039. Upon entering the valve manifold 6039, the pressure of the water may be regulated to a predetermined pressure by a pressure regulator 6040. The predetermined pressure may be between 15-30 psig (e.g., 20 psig). The pressure and temperature of the water may be sensed by a pressure sensor 6044 and a temperature sensor 6042 in data communication with the controller 6034. The filtered raw water may then proceed to a blowdown heat exchanger 6008B and a product water heat exchanger 6008A.

[0040] The flow path to the blowdown heat exchanger may extend to the electronics housing 6046 of the system 6000. As the water travels to the blowdown heat exchanger 6008B, the flow path route may establish a heat exchange relationship with the electronic components of the electronics housing 6046. Thus, the filtered raw water may serve to cool the electronics in the electronics housing 6046 on its way to the blowdown heat exchanger 6008B. Alternatively or additionally, the raw water on its way to the product heat exchanger 6008A may be routed so as to be in a heat exchange relationship with the electronics of the electronics housing 6046. As shown, the electronics housing 6046 may be accompanied by an electronics temperature sensor 6048 that provides temperature data to the controller 6034. In an embodiment, there may be multiple temperature sensors 6048 within the electronics housing 6046 for added redundancy and / or to monitor specific components (eg, power modules).

[0041] The source proportioning control valves 6050A, B may be operated by the controller 6034 to adjust the mass fraction of raw water flowing through each of the blowdown and product heat exchangers 6008A, B. As discussed above, the mass fractions may be selected to achieve a desired temperature of one or more of the process streams from the water purifier 6010. However, it should be noted that the mass fractions may also be controlled to ensure sufficient cooling of the electronics housing 6046. In some embodiments, at least a predetermined fraction of the incoming raw water may be provided to the blowdown heat exchanger 6008B to ensure sufficient cooling. The controller 6034 may alter the mass fractions of the heat exchangers 6008A, B when temperature data from the electronics temperature sensor 6048 indicates that the temperature of the electronics housing 6046 is above a threshold value.

[0042] After passing through the blowdown and product heat exchangers 6008A,B, the filtered raw water streams may recombine and enter the sump 6052 of the water purifier 6010 through a raw fluid input contained in the sump 6052. The sump 6052 may include at least one heating element 6054. The at least one heating element 6054 may be a resistive heater. A thermal fuse 6056 may also be included as a fail-safe mechanism. The at least one heating element 6054 may heat the contents of the sump 6052 based on analysis of data from a sump temperature sensor 6058 by the controller 6034. Each heating element 6054 may be associated with a temperature sensor 6059 to provide a temperature reading at the heating element 6054. The at least one heating element 6054 may provide thermal energy to the incoming raw water to assist or cause evaporation of the raw water in an evaporator 6060 of the water purifier 6010. The evaporator 6060 may be formed, at least in part, from a shell-and-tube heat exchanger, as described elsewhere herein. The upper portion of the evaporator 6060 (relative to gravity) may include a vapor chamber 6072. The evaporator 6060 may convert the raw fluid from the raw fluid input into low-pressure vapor and condense the stream as the raw fluid travels toward the vapor chamber 6072.

[0043] As the raw water boils, steam rises from the now more concentrated raw water and may pass through a mist eliminator 6062 located within the steam chamber 6072. The mist eliminator 6062 may prevent water molecules still in the liquid phase from exiting the evaporator 6060. The mist eliminator 6062 may be, for example, any of the exemplary mist eliminators described herein. After removal of the mist, the water vapor may travel to a compressor 6064. The compressor 6064 may be any suitable compressor, such as any of those described herein. The compressor 6064 may compress the water vapor, increasing its temperature in the process. The system 6000 may include a pre-compression temperature sensor 6066 and a post-compression temperature sensor 6068. Data from these temperature sensors 6066, 6068 may be provided to a controller 6034, which may use this data to control the compressor 6064. A compressor temperature sensor 6070 (or multiple redundant compressor temperature sensors) may further be included to provide temperature data related to the compressor 6064 to the controller 6034 .

[0044] In some embodiments, the controller 6034 may include multiple processors that may control various components of the system 6000. In some embodiments, a main control processor and a peripheral control processor may be included in the controller 6034. The peripheral control processor may control at least one heating element 6054 and the compressor 6064, while the main control processor receives sensor data and controls other components of the system 6000. These processors may exchange data to facilitate the division of responsibilities. For example, sensor data and / or high-level commands from the main control processor may be provided to the peripheral control processor, which may provide its command output to the main control processor.

[0045] As the pure steam travels from the evaporator 6060 to the compressor 6064, impurities in the raw water may concentrate to form a blowdown process stream. In this exemplary embodiment, the blowdown process stream may enter a blowdown storage tank 6014 from the evaporator 6060. The blowdown storage tank 6014 may be disposed laterally relative to and in communication with the steam chest 6072. A blowdown level sensor 6074 may be included associated with the blowdown storage tank 6014 and in data communication with the controller 6034. The blowdown level sensor 6074 may directly measure the level of concentrate or blowdown in the steam chest 6072 and generate a data signal indicative thereof. Data from the blowdown level sensor 6074 may be used by the controller 6034 to ensure that a sufficient amount of concentrate is maintained in the evaporator 6060 and to verify that a desired amount of blowdown flux is present. The blowdown reservoir 6014 as well as the sump 6052 may be in direct communication with the drain 6018 via a fluid conduit when excess fluid needs to be drained from the water purifier 6010 .

[0046] A product water process stream may be formed by condensing steam passing from the high pressure steam outlet of the compressor 6064 to the condenser 6076. At least a portion of this steam may condense in a section of the evaporator 6060 that is in communication with the condenser 6076. In various embodiments, the condenser 6076 may be in heat exchange relationship with several exterior surfaces of the evaporator 6060. The latent heat of condensation provided in the condenser 6076 from the condensing water may aid in the evaporation of the raw water in the evaporator 6060.

[0047] As shown, a product storage tank 6012 may be attached to and in communication with the volume of the condenser 6076. The product storage tank 6012 may include a product level sensor 6078 in data communication with the controller 6034. The product level sensor 6012 may be used to determine the volume of available product water and may also be used to verify fluid flow from the product storage tank 6012. The product storage tank 6012 may be positioned to be flush with a portion of the condenser 6076. Thus, the product level sensor 6078 may measure both the level of water in the product storage tank 6012 and the level of water in the condenser 6076. From this, the total volume of available product water may be inferred. The product storage tank 6012 may be arranged so that the product level sensor 6078 can measure an available product level of 1-10 L (e.g., 1, 2, 5, or 6 L), although any volume range is possible. In this sense, product reservoir 6012 may function as an auxiliary product reservoir.

[0048] If the product level sensor 6078 measures the level of condensate in the condenser 6076, the condenser may be divided into two compartments. The first compartment may be the condensation compartment. The second compartment may be the condensate accumulation compartment. The volume of the second compartment may be equal to the maximum available product level measured. When the second compartment is not full, the unfilled portion of the second compartment may function similarly to the first compartment and provide a condensation surface for the high-pressure steam to condense on. The product storage tank 6012 may be fluidly connected to the condensate accumulation compartment adjacent to the condensate accumulation surface where condensate first begins to accumulate (e.g., the bottom of the condenser 6076). This may allow the product level sensor 6078 to begin measuring an accurate amount of available product water immediately after the process stream begins to accumulate.

[0049] The product reservoir 6012 may also be in communication with a feed pump 6080. The feed pump 6080 may pump fluid from the product reservoir to the compressor 6064. This fluid may serve as a refrigerant for the compressor 6064 and as a lubricating fluid for one or more bearings of the compressor 6064. Because the bearing feed may be a source of purified water, a return path may not be included. Instead, the fluid may enter the compressor 6064 after use and be returned to the condenser 6076 without losing its purity. The pressure and temperature of the bearing feed fluid may be monitored by a bearing feed pressure sensor 6081 and a bearing feed temperature sensor 6083, each in data communication with the controller 6034.

[0050] After leaving the storage tanks 6012, 6014, the blowdown stream and the product process stream may flow to their respective heat exchangers 6008A, B. For the product process stream, after passing through the product heat exchanger 6008A, the stream may pass through several sensors 6082A-D downstream of the product heat exchanger 6008A. These sensors 6082A-D may sense various properties of interest in the product stream. While the properties of interest may be any of those described herein, in certain embodiments, the sensors 6082A-D may include first and second conductivity sensors and first and second temperature sensors. In some embodiments, one or more of the sensors 6082A-D may be included together as part of a sensor assembly. The controller 6034 may monitor the data generated by the sensors 6082A-D to determine how to route the product stream. If the product water meets the quality requirements of the medical system 6004 (e.g., within a predetermined temperature range and below a predetermined conductivity threshold), the point-of-use valve 6086 may be activated to allow the product flow to proceed to the medical system 6004. A medical system check valve 6088 may be included to ensure this flow is unidirectional.

[0051] If the quality of the product stream conflicts with at least one requirement of the medical system 6004, the controller 6034 may actuate the diverter valve 6084. When actuated, the diverter valve 6084 may establish a flow path for the process stream to a destination in the drain 6018 to be discarded. A drain check valve 6090 may be included to ensure that the flow from the system 6000 to the drain 6018 is one-way.

[0052] The blowdown flow may be directed to the drain 6018. However, before reaching the drain 6018, the blowdown flow may proceed through a check valve 6097 to the mixing reservoir 6092. As shown, a blowdown reservoir outlet valve 6094 may gate the flow of cooled blowdown from the blowdown heat exchanger 6008B to the mixing reservoir 6092. A blowdown temperature sensor 6096, which may be in data communication with the controller 6034, may monitor the temperature of the blowdown entering the mixing reservoir 6092. The mixing reservoir 6092 may be in selective communication with the condenser 6076 via a vent valve 6098, which is actuated by the controller 6034. The vent valve 6098 may be periodically actuated to vent water vapor, volatiles, air, or other non-condensable gases from the condenser 6076 to maintain optimal operation of the water purifier 6010. A vacuum breaker 6099 may be included in the vent line to prevent a vacuum from forming within the purifier 6010 as it cools (e.g., after use) and its internal pressure drops. In the mixing reservoir 6092, the exhausted gases may combine with the relatively low temperature blowdown process stream to cool and condense the exhausted gases, so that hot gases can be safely vented from the condenser 6076 as needed.

[0053] When needed, a source diversion valve 6100 operated by the controller 6034 may be opened to allow raw water to enter the mixing reservoir 6092 to provide additional cooling. The operation of the source diversion valve 6100 may be based, at least in part, on the temperature of the blowdown stream as determined from data provided by the blowdown temperature sensor 6096. Additionally or alternatively, actuation of the source diversion valve 6100 may be based, at least in part, on the amount or duty cycle of exhaust of the vent valve 6098 and / or the temperature of the electronics housing 6046. The source diversion valve 6100 may also be actuated by the controller 6034 to an open state when the water purifier 6010 already has a sufficient supply of source water. The source diversion valve 6100 may also be used to rinse the filter elements 6006A, B before a sample is taken. The source diversion valve 6100 may allow a high velocity flow of source fluid to cool the electronics housing 6046 if the temperature sensor 6048 indicates that the temperature of the electronics housing 6046 violates a predetermined threshold criterion.

[0054] Components of the system 6000 that operate at high temperatures may be compartmentalized within a high temperature compartment housing 6102 of the system 6000. As described elsewhere herein, this compartment may be insulated to increase the efficiency of the system 6000. A leak sensor 6104 may be included in the high temperature compartment 6102 to monitor the integrity of the system 6000 and provide data to the controller 6034. The leak sensor 6104 may include a conductivity sensor that monitors the presence of liquid within the high temperature compartment 6102. Alternatively, the leak sensor may be an optical sensor that monitors a drip pan or similar reservoir.

[0055] Referring now to FIG. 3 , an exemplary block diagram of a system 6000 is shown. The system 6000 of FIG. 3 has several differences compared to FIG. 2 . As shown, the system 6000 of FIG. 3 includes an evaporator reservoir 6015 in fluid communication with and disposed external to the evaporator 6060. The evaporator reservoir 6015 may include an evaporator water level sensor 6073 in data communication with the controller 6034. The evaporator water level sensor 6012 may be used to determine the volume of water held in the evaporator and to verify that fluid is flowing to the evaporator 6060. The evaporator reservoir 6015 may be positioned to be flush with a portion of the evaporator 6060. Thus, the evaporator water level sensor 6073 may measure both the level of water in the evaporator reservoir 6015 and the level of water in the evaporator 6060. These values ​​may be used to help direct the filling of the evaporator 6060 during start-up or other times when the water level has not yet reached the blowdown reservoir 6012. These values ​​may also be used as input variables to various control loops for the clarifier 6010 implemented in the controller 6034 during production of the product stream.

[0056] The system 6000 may also include an air filter 6093. The air filter may be a HEPA air filter or an air filter with a pore size of 0.2 microns or less. The air filter may be in series with a check valve 6095 leading to a vacuum breaker 6099 of the purifier 6010. This filter may act as a safeguard to prevent the ingress of debris and microorganisms during operation of the vacuum breaker 6099. The system 6000 may also include an overpressure relief valve 6091 that may open to relieve pressure from the purifier 6010 if the pressure within the purifier 6010 rises above a predetermined value. The relief valve 6091 may be purely mechanical or under the control of the controller 6034, depending on the embodiment.

[0057] The exemplary system shown in FIG. 3 also includes a single drain 6018. A diverter valve 6084 may gate the flow path to the mixing barrel 6092. When product water needs to be sent to the drain 6018 (e.g., when sensing criteria are not met or too much product water is accumulating in the condenser 6076), the diverter valve 6084 may be actuated to open the flow path. In certain embodiments, the controller 6034 may control for a target product level in the product storage tank 6014 or the condenser 6076. The discarded product may then flow through a check valve 6085 to the mixing barrel 6092. When combined with all other waste or waste process streams, the fluid in the mixing barrel 6092 may proceed to the drain 6018.

[0058] The lines to the medical system 6004 may be insulated, as indicated by the bold lines. This may help prevent heat loss as fluid travels from the sensors 6082A-D to the medical system 6004. In certain embodiments where water may be provided to the medical system 6004 at a high temperature, insulation may prevent a user from coming into contact with hot lines. Any suitable insulation may be used.

[0059] Referring now to FIG. 4, another exemplary block diagram of a system 6000 is shown. A third heat exchanger 6008C is shown in this exemplary diagram. This heat exchanger 6008C may be a counterflow heat exchanger similar to the other heat exchangers described herein. The exemplary third heat exchanger may exchange heat between the purifier feed fluid and a hot output stream from the medical system 6004, which in some embodiments may be a waste stream from the medical system 6004. For example, the third heat exchanger 6008C may receive spent dialysate or waste fluid from a hemodialysis or peritoneal dialysis device. Such a third heat exchanger 6008C may help improve efficiency and facilitate temperature control of various process streams in the system 6000 where a hot output stream from the medical system 6004 is available.

[0060] The third heat exchanger 6008C is disposed intermediate the at least one filter 6006 and the first and second heat exchangers 6008A, B. The filtered raw fluid exiting the at least one filter may pass through the third heat exchanger 6008C before proceeding to the first and second heat exchangers 6008A, B. Alternatively, the third heat exchanger 6008C may be located intermediate the at least one filter 6006 and only one of the first and second heat exchangers 6008A, B (e.g., product water heat exchanger 6008A). The third heat exchanger 6008C may be included as an optional fluid path for the raw fluid flowing through the system 6000. In such an implementation, the system 6000 may include a branch fluid path gated by one or more branch valves. If desired, the one or more valves may be actuated to establish raw fluid flow to the third heat exchanger 6008C or to direct fluid flow through separate fluid paths to the first and second heat exchangers. The branch valve may be actuated based on a control loop, for example, to establish and block a flow path for the raw fluid through the third heat exchanger 6008C. The third heat exchanger 6008C may be disposed intermediate the product heat exchanger 6008A and the medical system 6004 or the sensor assembly 6016 (with or without a valved branch fluid path).

[0061] The third heat exchanger 6008C may be configured to transfer heat from the high-temperature output of the medical system 6004 to the raw fluid en route to the purifier 6010. This may help lower the additional energy required to cause a phase change in the raw fluid in instances where the purifier 6010 is a distillation device. Alternatively, if the third heat exchanger 6008C is intermediate the product heat exchanger 6008A and the sensor assembly 6016, the output of the medical system 6004 may assist in heating or cooling the product process stream, depending on the temperature difference between the two fluids. In the example shown, the high-temperature output of the medical system 6004 is directed to waste or drain destination 6018 in this exemplary embodiment. In other embodiments, the third heat exchanger 6008C may function as a cooler for the medical system 6004. The medical system 6004 may, in some embodiments, recirculate fluid through the third heat exchanger 6008C to exchange heat with the relatively low-temperature raw fluid stream. This may be desirable, for example, if the product process stream provided to medical system 6004 is too warm for a particular operation. One or more valves may control whether the output from medical system 6004 is recycled to medical system 6004 after heat transfer in third heat exchanger 6008C or is discarded to drain destination 6018.

[0062] Continuing with reference to FIG. 4 , one of the first and second heat exchangers 6008A,B includes a bypass valve 6009. This bypass valve 6009 may be utilized to provide additional cooling to one or more process streams from the clarifier 6010 as they pass through the heat exchangers 6008A,B. In this exemplary embodiment, the bypass valve 6009 is included at the raw water output of the product heat exchanger 6008A. The bypass valve 6009 may allow the raw fluid exiting the product heat exchanger 6008A to be diverted directly to the drain destination 6018, as shown. Such a bypass valve 6009 may be used when extra cooling of the product process stream may be required. The bypass valve 6009 may be actuated to a bypass state, and the duty cycle of at least one of the valves controlling the flow of raw water through the first and second heat exchangers 6008A,B may be altered (e.g., increased to 90-100%). Thus, relatively low temperature raw water may be transferred through product heat exchanger 6008A at a rapid rate to quickly capture heat from the product process stream and help bring the product process stream down to a target temperature. This large volume of fast-flowing raw water may be discarded to a drain via bypass valve 6009 if the raw fluid volume exceeds demand from clarifier 6010. Bypass valve 6009 may be actuated to a bypass state when controller 6034 (see, e.g., FIG. 2 ) determines that at least one process variable is outside a predetermined threshold. The at least one process variable may be, or may be defined in part by, the relationship between the condensate temperature taken downstream of condensate heat exchanger 6008A and the raw fluid temperature.

[0063] On the other hand, if the temperature of the process stream exiting the first or second heat exchanger 6008A,B is too low, the controller 6034 of the system 6000 (see, e.g., FIG. 2 ) may direct that the raw fluid be drawn at least in part from an alternate fluid source 6003. The alternate fluid source 6003 may be temperature controlled and may be a hot water source. The hot water source may be a domestic hot water heater or water tank, a heated storage tank component of the system 6000, or any other suitable hot water source. In the example shown, only a first fluid source and a second alternate fluid source are shown, but in other embodiments, there may be more than one alternate fluid source 6003. The first fluid source may be associated with a first set of fluid input valves, and the second fluid source may be associated with a second set of fluid input valves that includes at least one valve that is not in the first set of input valves.

[0064] By drawing raw fluid at least in part from the alternate fluid source 6003, the temperature drop of the process stream from the purifier 6010 as it passes through the first and second heat exchangers 6008A, B may be reduced. Additionally, fluid may be drawn from the alternate fluid source 6003 if a process variable violates a predetermined threshold. For example, if the duty cycle of the heating element 6054, the source valve command duty cycle 6432 (see, e.g., FIGS. 100-101C ), and / or the speed of the compressor 6072 exceed a predetermined threshold, fluid may be drawn from the alternate fluid source 6003. This may help enable the purifier 6010 to purify more fluid in the same amount of time or may help minimize demands on various components of the purifier 6010, such as the heating element 6054 or the compressor 6072.

[0065] C2 embodiment Referring now to FIG. 5, an exemplary embodiment of the system 6000 shown in FIG. 1 is illustrated. For clarity, only the raw water carrier fluid line 6126 is shown in FIG. 5. The raw water may enter the system 6000 at connector 6120. A manual shutoff valve 6032 may be included to prevent the flow of raw water into the system 6000. The raw water may flow through several filters 6006A, B. In the example shown, these filters may be 5 L activated carbon filters. A user-operated sample port 6038 is included between the filters 6006A, B. The sample port 6038 in this example includes a manually actuated ball-type valve. Pre-filtration and post-filtration pressure transducers 6036, 6044 may also be included. The system 6000 includes a pressure regulator 6040 that can control the pressure of the raw water to a predetermined value (e.g., 20 psig).

[0066] The raw water flow may be split to facilitate separate allocation of the raw water to the product and blowdown heat exchangers 6008A, B. On its way to the blowdown heat exchanger 6008B, the raw water fluid line 6126 may extend to the electronics heat exchanger inlet 6122. The raw water may flow through fluid conduits within the electronics housing 6046 and exit the electronics housing 6046 through the electronics heat exchanger outlet 6124. Although not shown, the fluid conduits within the electronics housing 6046 may be plumbed in non-straight lines or serpentine (e.g., switchback) patterns to help maximize heat transfer. A raw water fluid line 6126 extending from the electronics heat exchanger outlet 6124 may provide a fluid path for the raw water to the blowdown heat exchanger 6008B. A branch may be included in this section of the raw water fluid line 6126 to allow the raw water flow to be diverted to the mixing reservoir 6092 if desired. The raw water fluid line 6126 may enter the high temperature section housing 6102 via a product heat exchanger through-passage 6128 and a blowdown heat exchanger through-passage 6130 within the high temperature section housing 6102 .

[0067] 6-7, which show diagrams of portions of the system 6000 with the hot section housing 6102 removed. Again, for clarity, only the raw water fluid line 6126 is shown, not the conveyance of the various process streams. The raw water fluid line 6126 may be connected to the raw water inlets 6132A,B of the respective heat exchangers 6008A,B. The raw water may flow through the heat exchangers 6008A,B to the respective raw water outlets 6134A,B. After exiting the heat exchangers 6008A,B, the raw water streams may recombine and proceed through the raw water line 6126 to the sump 6052 of the water clarifier 6010.

[0068] Referring now also to FIG. 8 , a diagram of exemplary heat exchangers 6008A, B is shown. The heat exchangers 6008A, B may each be configured as a spiral of piping through which the raw water and various process streams of the system 6000 may flow. The spiral formed by each of the heat exchangers 6008A, B may have a substantially constant radius and pitch. The heat exchangers 6008A, B may be configured concentrically, with one of the heat exchangers 6008A, B having a smaller radius and positioned inside the other. In the exemplary embodiment shown in FIG. 8 , the blowdown heat exchanger 6008B is positioned inside the product heat exchanger 6008A. The fluid path lengths within the product and blowdown heat exchangers 6008A, B may be substantially equal. The pitch of each heat exchanger 6008A, B may be substantially equal. As a result, the inner, or small radius, heat exchanger 6008B may be taller than the outer heat exchanger 6008A.

[0069] A cross-sectional view of a portion of an exemplary heat exchanger 6008A, B is shown in Figure 9. As shown, each heat exchanger 6008A, B includes a large diameter source flow conduit 6136A, B that forms the exterior surface of the heat exchanger 6008A, B. Although these source flow conduits 6136A, B are shown having substantially equal diameters, in some instances their diameters may differ, with one being larger than the other.

[0070] Among the source flow conduits 6136A,B are conduits through which process streams from the water purifier 6010 are conveyed. The product water heat exchanger 6008A may include at least one product flow conduit 6138 disposed within its source flow conduit 6136A. Each of the at least one product flow conduit 6138 may be of equal or different diameters. The blowdown heat exchanger 6008B includes multiple internal flow conduits. In the example of FIG. 9 , the blowdown heat exchanger includes a blowdown flow conduit 6140 and a vent flow conduit 6142 within its source flow conduit 6136B. In some embodiments, additional flow conduits may be included therein. For example, multiple blowdown or vent conduits 6140, 6142 may be included within the source flow conduit 6136B. The blowdown flow conduit 6140 and the vent flow conduit 6142 may be positioned side-by-side as shown, or may be braided or intertwined together in some embodiments. The product flow conduit 6138 may be similarly braided or intertwined, depending on the embodiment.

[0071] As best shown in FIG. 9 , to maximize the compactness of the heat exchangers 6008A,B, the pitch of the helix of the heat exchangers 6008A,B may be relatively shallow. For example, the pitch may be 5-40% greater than the outer diameter of the source flow conduits 6136A,B. In other embodiments, the pitch may be approximately equal to the outer diameter of the source flow conduits 6136A,B, with each turn of the helix adjacent to its neighbor. A pitch greater than the outer diameter of the source flow conduits 6136A,B may be desirable if the source flow conduits 6136A,B are constructed from a material that efficiently conducts heat, such as stainless steel or other metals. If the source flow conduits 6136A,B are constructed from high-temperature silicon or similar materials, the air gap between turns may be reduced or eliminated. Air gaps may also be eliminated if a material with high thermal conductivity is used.

[0072] 10-11, additional views of portions of the exemplary system 6000 are shown. After raw water (shown as stippled lines in FIG. 10) travels into the sump 6052, the water may begin to fill several evaporator tubes 6140. The evaporator tubes 6140 may extend from the volume of the sump 6052 through the condenser 6076 to the volume of the steam chest 6072. The first and second tube sheets 6142A,B may include receiving holes 6144 for receiving the ends of each evaporator tube 6140. The tube sheets 6142A,B may hold the evaporator tubes 6140 in a generally evenly spaced pattern within the volume of the condenser 6076. The tube sheets 6142A,B may also form a seal or include gasket members that form seals around the ends of the evaporator tubes 6140. This seal may prevent fluid communication between the evaporator tubes 6140 and the interior volume of the condenser 6076. At least one plate 6143 may also be included in the condenser 6076, functioning as a baffle to direct incoming steam to the exterior surface of the evaporator tubes 6140. A second tube sheet 6142B may form the bottom wall of the steam chamber 6072. When raw water enters the steam chamber 6072, the water may collect at the bottom of the steam chamber 6072 above the second tube sheet 6142B.

[0073] In this exemplary embodiment, fewer than 100 (specifically, 96) evaporator tubes 6140 are included. In other embodiments, a greater or lesser number of evaporator tubes 6140 may be included. Each evaporator tube 6140 may have a substantially equal diameter. The diameter of the evaporator tubes 6140 may be between 5 and 10% (e.g., about 6%) of the diameter of the condenser 6072. In some embodiments, the evaporator tubes 6140 may not all be of equal diameter. At least one or more of the evaporator tubes 6140 may be of different diameters.

[0074] In some embodiments, the evaporator tubes 6140 may have different diameters depending on their location. For example, the evaporator tubes 6140 in a first section of the evaporator may have a first diameter, those in a second section may have a second diameter, those in a third section may have a third diameter, and so on. In some embodiments, those extending through a central region of the condenser 6076 volume may have a first diameter, and those in regions more distal to the central region may have a second diameter. The first diameter may be larger or smaller than the second diameter, depending on the embodiment. In some embodiments, a diameter gradient of the evaporator tubes 6140 may be established from the evaporator tubes 6140 extending through a central portion of the condenser 6076 volume and the evaporator tubes 6140 located most distal to the central portion of the evaporator tubes 6140. For example, tubes that become progressively larger or smaller with increasing distance from the central portion may be included.

[0075] The evaporator tubes 6140 may occupy between 25-50% (e.g., about 37%) of the interior volume of the condenser 6076. The material from which the evaporator tubes 6140 are constructed may vary depending on the embodiment, but a material with high thermal conductivity may be used. The materials used may be any of those described elsewhere herein.

[0076] In some embodiments, the evaporator tubes 6140 may be made from the same or similar material used to construct the tube sheets 6142A,B. Both the evaporator tubes 6140 and the tube sheets 6142A,B may be metallic materials with high thermal conductivity. In some examples, stainless steel may be used. The evaporator tubes 6140 may be welded, brazed, or otherwise bonded to the tube sheets 6142A,B, which may allow for a reduction in the overall size of the purifier 6010 when compared to embodiments in which the tube sheets are constructed from an elastomeric material such as ethylene propylene diene monomer (EPDM) rubber. When welded, brazed, or similarly attached, the joints between the tube sheets 6142A,B and the individual evaporator tubes 6140 may also form a fluid-tight seal. Thus, the tube sheets 6142A,B may be thinned while maintaining a robust seal between the condenser 6076 volume and the sump 6052 / vapor chamber 6072.

[0077] Although not shown in this embodiment, the evaporator tubes 6140 may include packing elements (see, e.g., FIG. 62), such as rods, that fill a percentage of the cross-sectional area of ​​each (or possibly only some) of the evaporator tubes 6140. This may encourage a thin layer or film of source fluid to exist between the exterior of the packing elements and the interior surface of the evaporator tubes 6140 within which the packing elements are disposed.

[0078] 12-16, as heat from heating element 6054 (see, e.g., FIG. 2) and condensing steam in condenser 6076 evaporate the raw water, a blowdown process stream or concentrate may be produced. This blowdown process stream may fill a portion of the volume of steam chest 6072. As shown, blowdown or concentrate storage tank 6014 may be attached to the side of steam chest 6072. An obstruction 6146 (best shown in FIG. 13) may be included in or define a portion of an inlet path 6148 from steam chest 6072 to blowdown storage tank 6014. For example, inlet path 6148 may include a first portion 6333 and a second portion 6335. This second portion may be defined, at least in part, by obstruction 6146. Obstruction 6146 may be a weir or similar barrier that blocks a portion of blowdown storage tank 6014. The obstruction 6146 may substantially prevent splashing and other violent liquid movement due to boiling in the steam chamber 6072 from disturbing the liquid in the shielded portion 6334. A portion of the inlet path 6148 may be disposed within the interior volume of the blowdown reservoir 6014.

[0079] The illustrated obstruction 6146 includes a plate integral with the wall of the inlet path 6148 and opposite the inlet port 6336 from the steam chest 6072. This plate also extends downward into the blowdown reservoir 6012 at an angle across the first portion 6333 of the inlet path 6148. This segment may block splashes and other disturbances from traveling from the unshielded portion 6337 to the shielded portion 6334. As shown, a vent passage 6338 may also be included to allow gases displaced by the incoming blowdown or generated due to evaporation to exit the blowdown reservoir 6012. The vent passage 6338 may run substantially parallel to and above (with respect to gravity) the first portion 6333 of the inlet path 6148. The vent passage 6338 in this exemplary embodiment may lead to the steam chest 6072. The vent passage 6338 may have a smaller cross-sectional area than the first portion 6333 of the inlet path 6148. A vent hole 6152 may be included in the wall of the steam chest 6072 to establish fluid communication between the vent passage 6338 and the steam chest 6072. The vent hole 6152 may be of a smaller cross-sectional area than the vent passage 6338.

[0080] As mentioned above, the liquid level in the blowdown reservoir 6014 may be sensed by a blowdown level sensor 6074. While any suitable sensor for measuring the liquid level in the blowdown reservoir 6014 may be used, a floating sensor similar to those described elsewhere herein is depicted. The blowdown level sensor 6074 may include a float assembly including a float 6154 attached to an arm 6156. In this example, the float 6154 is depicted as a hollow structure attached to the end of the arm 6156. In other embodiments, the float 6154 may be solid and made from a buoyant material that is resistant to heat and corrosion. The arm 6156 may be coupled to a pivot 6158. Preferably, the blowdown level sensor 6074 may be disposed within the shielded portion 6334.

[0081] As the liquid level in the blowdown reservoir 6014 changes, the position of the float 6154 may similarly rise and fall throughout the float's swing range. The float 6154 is attached to an arm 6156, which may pivot about a pivot axis 6158. The blowdown level sensor 6074 may include a Hall Effect sensor 6160, which, now referring primarily to FIG. 16 , monitors the position of at least one magnet 6155, which displaces as the liquid level changes. The at least one magnet 6155 may be located on the float 6154 or the arm 6156, for example. In the illustrated example, two magnets 6155 may be mounted adjacent to the pivot axis 6158. The blowdown reservoir 6014 may be arranged to allow the blowdown level sensor 6074 to directly measure the liquid level in the steam chest 6072, at least when the clarifier 6010 is in a certain state (e.g., during start-up). The deflection or displacement range of float 6154 may be selected so that float 6154 may rise with the liquid level in steam chamber 6072. In this example, an embodiment is described having a Hall Effect sensor 6160, but other types of sensors may be used. For example, some embodiments may include a rotary encoder or potentiometer instead of or in addition to a Hall Effect sensor.

[0082] The float assembly's swing range may be selected so that the range includes at least a point at the same height as all steam chamber liquid levels expected during the operating conditions (e.g., start-up) of the particular purifier 6010. Thus, the blowdown level sensor 6074 may be a direct level sensor that directly measures the level of concentrate (if within the expected range) in the steam chamber 6072 to which the blowdown storage tank 6014 is attached.

[0083] In some embodiments, while purified liquid is being produced by the purifier 6010, the liquid level may be sensed in a less direct manner. For example, the blowdown level sensor 6074 may have an excursion range that includes a point above the expected range of liquid level in the steam chest 6072. Violent boiling action occurring in the steam chest 6072 may occasionally splash liquid into the blowdown level sensor 6074, filling it. The controller 6034 (see, e.g., FIG. 2 ) may analyze the rate of blowdown accumulation to determine whether the liquid level in the steam chest 6072 is within an expected range. If the rate is outside the defined range, it may be determined that the liquid level in the steam chest 6072 requires adjustment or is abnormal.

[0084] Referring now to FIG. 17, a perspective view of the clarifier 6010 and blowdown reservoir 6014 is shown. For clarity, only the blowdown flow conduit is shown in FIG. 17. As shown, the blowdown reservoir 6014 may be attached to a blowdown flow conduit 6162, which serves as an outlet to the blowdown reservoir. The outlet may establish a flow path from the blowdown reservoir 6014 to the blowdown heat exchanger 6008B. A blowdown reservoir valve 6356 (see, e.g., FIGS. 42-43) may also be included to control purging of the blowdown process stream from the clarifier 6010. The blowdown reservoir valve 6356 may be operated by the controller 6034 (see, e.g., FIG. 2) to maintain the liquid level in the steam chest 6072 within a desired range. Data from the blowdown level sensor 6074 may be used to direct the operation of the blowdown reservoir valve 6356. Because the water level in the steam chest 6072 can be directly monitored via the blowdown level sensor 6074, the level of concentrate in the steam chest 6072 can be controlled to a known level via the blowdown reservoir valve 6356.

[0085] A number of manual drain valves 6166, 6168 may also be included. These manual drain valves 6166, 6168 may be used to empty the clarifier 6010 during maintenance or other periods of non-use. In the example shown in FIG. 17 , the manual drain valve 6166 is associated with the blowdown reservoir 6014. The manual drain valve 6168 is also associated with the sump 6052. The manual drain valves 6166, 6168 may be manually operated ball valves in certain implementations. While the valves 6166, 6168 are described as being manually operated, in other embodiments they may be actuated by the controller 6034.

[0086] 18 , an exploded view of an exemplary steam chest 6072 is shown. The steam chest 6072 may include a mist eliminator assembly 6062. The mist eliminator assembly 6062 may help prevent liquid-phase water from passing beyond the water purifier steam chest 6072. The mist eliminator assembly 6062 may establish a tortuous path from the boiling liquid at the bottom of the steam chest 6072 to the compressor 6064 of the system 6000. The tortuous path may make it difficult for vapor-entrained liquid-phase water droplets to pass through the mist eliminator assembly 6062.

[0087] In the illustrated example, the mist eliminator assembly 6062 includes several mist elimination levels 6170A-C. The levels 6170A-C include several openings 6172 spaced to create a long, serpentine path for the steam. The first level 6170A includes openings 6172 around its periphery. These openings 6172 are generally spaced at regular angular intervals around the level 6170. The next level 6170B includes a single central opening 6172. The second level 6170B thus forces the steam to change direction and move from the sides of the steam chamber 6072 to the center of the steam chamber 6072 in order to proceed to the next level 6170C. The third level 6170C, like the first level 6170A, includes openings arranged around the periphery. Again, the steam is forced to change direction and flow from the center of the steam chamber 6072 to the sidewalls 6174 of the steam chamber 6072. In other embodiments, the number of tiers may be different.

[0088] Due to the change in direction and the long travel path required to travel through the levels 6070A-C of the mist eliminator assembly 6062, droplets of liquid water may be prone to falling out of the steam. Each level 6170A-C of the mist eliminator assembly 6062 may have a sloped surface that allows liquid water to easily drain out of the mist eliminator assembly 6062. In this exemplary embodiment, the levels 6070A-C are all frustoconical in shape, sloping downward toward the sidewall 6174 of the steam chamber 6072. A small gap may exist between the levels 6170A-C and the sidewall 6174 of the mist eliminator assembly 6062 to allow liquid water to fall back into the liquid pool at the bottom of the steam chamber 6072.

[0089] 19-21 in addition to FIG. 18 , the mist eliminator assembly 6062 may also include a compressor feed channel 6176 through which the vapor passes before reaching the compressor 6064. The compressor feed channel 6176 may house a flow convolutor 6178 or vane pack. The flow convolutor 6178 or vane pack may divide the incoming vapor into several discrete flow channels 6180. Each of the flow channels 6180 may include at least one flow turning feature 6182. Again, these turning features 6182 may act to help eliminate any liquid-phase water droplets traveling through the mist eliminator assembly 6062.

[0090] As best shown in FIG. 19 , the flow path convoluter 6178 may include several individual plate members 6184 held together by a connector shaft 6186. The plate members 6184 are arranged in a nested or tiered arrangement, with progressively smaller plate members 6184 located more proximal toward the center of the steam chest 6072. The flow channels 6180 are defined by gaps between each adjacent plate member 6186 of the flow path convoluter 6178. In some embodiments, each flow path 6180 may be defined by an equal-sized gap. The gap may be less than 1 cm, for example, approximately 4.5 mm in some particular embodiments. Each of the individual plates 6184 includes several angled segments 6188 that make up the turning feature 6182. As best shown in FIG. 18, the flow path convolutor 6178 may also have a stepped region 6190 that complements and may abut the wall of the compressor feed channel 6176.

[0091] Referring now to FIG. 21 , a drip tray 6192 may form one of the walls of the compressor feed channel 6176. The drip tray 6192 may capture and direct any liquid-phase water droplets removed by the channel convolutor 6178. The drip tray 6192 may include several recessed features 6194 into which liquid can easily flow. The recessed features 6194 may include drainage openings 6196 in their most recessed portions to allow liquid to exit the compressor feed channel 6176. In the illustrated example, two types of recesses 6194 may be included. Some of the recesses are depicted as grooves with a gradation of groove depth as their proximity to the drainage openings 6196 increases. The grooves may be generally aligned with the flow redirection features 6182 of the channel convolutor 6178 when the channel convolutor 6178 is installed in the compressor feed channel 6176. A funnel-shaped recess may also be included in the drip tray 6192. The funnel-shaped recess may be in the shape of a truncated cone with its drain outlet 6196 forming an opening in the truncated cone. The funnel-shaped recess may be disposed at a location downstream of the flow path convolutor 6178 when the flow path convolutor 6178 is installed in the compressor feed channel 6176.

[0092] Referring now primarily to FIG. 22 , the third level 6170C of the mist eliminator assembly 6062 may include a berm 6198. The berm 6198 may protrude from the third level 6170C toward the drip pan 6192. As shown, the berm 6198 is in the shape of a portion of a spiral. The berm 6198 also includes a hooked portion 6200 that is approximately perpendicular to the portion of the berm 6198 from which it extends. The berm 6198 is disposed such that all of the drain openings 6196 in the drip pan 6192 are on the first side of the berm 6198. Liquid that travels through the drain openings 6196 to the surface of the third level 6170C flows along the surface of the third level 6170C and may be redirected by the berm 6198. Because the berm 6198 is in the shape of a portion of a spiral and the surface of the third level 6170C is sloped, the berm 6198 can redirect liquid along a downwardly sloping path toward an end 6202 of the berm 6198. This end 6202 can be positioned adjacent to the opening 6172 along the periphery of the third level 6170C.

[0093] Referring now primarily to FIGS. 23 and 24 , after passing through the mist eliminator assembly 6062, the vapor may be compressed by a compressor 6064. The compressor 6064 may be an impeller-type compressor 6064, although other compressor models may be used in alternative embodiments. The compressor 6064 in this exemplary embodiment is mounted off-center relative to the longitudinal axis of the steam chest 6072. The steam chest 6072 includes a receiving recess 6210 recessed into the sidewall 6174 of the steam chest 6072. The receiving recess 6210 protrudes into the interior volume of the steam chest 6072. The various levels 6170A-C of the mist eliminator assembly 6062 may include recess receiving cavities 6212 (see, e.g., FIG. 22 ) that receive the receiving recess 6210. A motor 6214 may fit within the receiving recess 6210. The motor 6214 may be, for example, any of those described elsewhere herein or similar thereto. The motor 6214 may receive power via a motor power cable 6226.

[0094] The motor 6214 may drive an impeller 6216 mounted within the compressor housing 6218A,B. The impeller 6216 is attached to an impeller rotor assembly 6232, which may be rotated via operation of the motor 6214. The illustrated impeller 6216 may be a single-stage design, although a multi-stage design, such as any of those described herein, may alternatively be used. Because the compressor 6064 is mounted off-center, the axis of rotation of the impeller 6216 may also be off-center with respect to the longitudinal axis of the steam chest 6074. The axis of rotation of the impeller 6216 may extend through the steam chest 6074 and parallel to the longitudinal axis of the steam chest 6074.

[0095] Steam may enter compressor housing 6218A,B through inlet 6220, be compressed by rotating impeller 6216, and exit compressor 6064 through outlet 6222 at an elevated pressure and temperature. The temperature of the steam entering compressor 6064 from inlet 6220 may be sensed by inlet temperature sensor 6066. Similarly, the temperature of the compressed steam exiting compressor 6062 through outlet 6222 may be sensed by outlet temperature sensor 6068. These temperature sensors 6066, 6068 may be thermistors, thermocouples, or any other suitable temperature sensors.

[0096] The compressor 6064 may also include several mounts 6224. These mounts 6224 may include fasteners 6228 that extend through mounting projections 6230 included in portions of the compressor housings 6218A, B. The fasteners 6228 may couple into portions of the housing 6102 (see, for example, FIG. 5 ). This may allow the compressor 6064 and attached components to remain in place within the housing 6102 when other components of the purifier 6010 are removed. As described further later herein, the evaporator 6060, condenser 6076, sump 6052, and possibly other components may be removed during maintenance. The mounts 6224 may allow the compressor 6064 and attached components (e.g., steam chest 6072) to remain rigidly suspended from the housing 6102 without other support. The mount 6224 may include an elastomeric element that allows the mount 6224 to be a breakaway mount. In some embodiments, the elastomeric element may be a Series 60011 mount available from Era Industrial Sales, 80 Modular Ave, Commack, NY.

[0097] 25-28, the impeller 6216 may be captured between a first compressor housing portion 6218A and a second compressor housing portion 6218B. The first and second compressor housing portions 6218A, 6218B may each include a compression duct recess 6234A, 6234B (best shown in FIG. 25). When the compressor 6064 is assembled, these recesses may cooperate to form a compression duct 6236. The vanes 6238 of the impeller 6238 may be disposed within the compression duct 6236 and may travel within the compression duct 6236 during operation. Additionally, the compression duct 6236 may form part of a flow path for steam entering the compressor 6064, thereby enabling compression of the steam by rotation of the impeller 6216. As shown, the compression duct 6236 is generally toroidal in shape.

[0098] Interrupting the toroidal shape of the compression duct 6236 may be a reduced gap segment 6240 in the compression duct recess 6234A,B located between the inlet 6220 and the outlet 6222 of the compressor 6064. The reduced gap segment 6240 may help isolate the high-pressure section of the compressor 6064 (near the outlet 6222) from the low-pressure section of the compressor 6064 (near the inlet 6220). The reduced gap segment 6240 acts as a stripper plate, preventing a certain amount of high-pressure steam from the area near the outlet 6222 from returning toward the inlet 6220. In some embodiments, substantially only steam between the impeller vanes 6238 may be able to pass between the inlet 6220 and outlet 6222 regions. A pressure reduction channel 6242 formed by the recess in the reduced gap segment 6240 may be included adjacent the inlet 6220. These pressure reduction channels 6242 may allow high-pressure steam to expand to a lower pressure, minimizing its effect on the low-pressure steam coming from the mist eliminator assembly 6062. In this example, the pressure reduction channels 6242 are substantially wedge-shaped. The distance between the two housing sections 6218A, B at the location of the pressure reduction channels 6242 may be about 5-35% greater (e.g., 9% or 10% or about 9% or 10% greater) than the distance between the two housing sections 6218A, B at the reduced gap segment 6240.

[0099] 29-31, cross-sectional views of the inlet 6220 and outlet 6222 of the compressor 6064 are shown taken along the line indicated in FIG. 29. The inlet 6220 (FIG. 30) may be formed from flow channels disposed within the first and second compressor housing portions 6218A, B and first and second cover members 6244A, B. The first cover member 6244A may be attached to the first compressor housing portion 6218A. The first cover member 6244A seals the inlet 6220 from the external environment and may be coupled to the first compressor housing portion 6218A via fasteners or any other suitable fitting. A gasket member 6246 may be included to help assist in establishing a suitable seal. The first cover member 6244A may be shallow dish or cup shaped.

[0100] The second cover member 6244B may be attached to the second compressor housing portion 6218B via fasteners or any other suitable fitting. The second cover member 6244B may form a seal between the interior of the inlet 6220 and the external environment. A gasket member 6248 may be included to assist in establishing a suitable seal. The gasket members 6246, 6248 and other gasket members described herein may be O-rings (as shown), flat gaskets, form-in-place gaskets, or any other compressible or elastomeric members. The second cover member 6244B may be shaped like an elongated dome or stadium. The second cover member 6244B may also include a port 6250. The port 6250 may allow for installation of an inlet steam temperature sensor 6066.

[0101] The inlet 6220 may also include a divider 6252 that separates the incoming low-pressure steam flow into multiple flow paths. In the illustrated example, the divider 6252 is a bifurcated body that splits the incoming steam into a first flow and a second flow. The first flow created by the divider 6252 may lead to a first side 6254A of the impeller 6216. The second flow may lead to a second side 6254B of the impeller 6216. The divider 6252 may also form a portion of the wall of the compression duct 6236. In the exemplary embodiment, the divider 6252 includes a portion of the reduced gap segment 6240 of the compression duct 6236.

[0102] The outlet 6222 may be formed by flow channels in the first and second compressor housing portions 6218A,B, and a cover member 6256 and a condenser inlet fitting 6258. The cover member 6256 may be attached to the second compressor housing portion 6218B via fasteners or another suitable fitting. The cover member 6256 may form a seal between the interior of the outlet 6222 and the external environment. A gasket member 6260 may be included to assist in establishing a suitable seal. The cover member 6256 may include a port 6264. The port 6264 may allow for installation of an outlet steam temperature sensor 6068. As shown, the cover member 6256 may be generally dome-shaped.

[0103] Similar to the inlet 6220, the outlet 6222 may include a divider 6266. The divider 6266 may combine high-pressure steam flows emerging from multiple flow paths into a single flow path. In the illustrated example, the divider 6266 is a bifurcated body that combines the exiting steam into a single flow path. A first flow path created by the divider 6252 may pass from a first side 6254A of the impeller 6216 toward a condenser inlet fitting 6258. A second flow path may pass from a second side 6254B of the impeller 6216 to the condenser inlet fitting 6258. Both flows may combine at the condenser inlet fitting 6258. The divider 6266 may be shaped such that the first and second flows combine before reaching the condenser inlet fitting 6258. The divider 6266 may also form part of a wall of the compression duct 6236. In the exemplary embodiment, divider 6266 includes a portion of reduced gap segment 6240 of compression duct 6236 .

[0104] Although the compressor 6064 may be mounted off-center relative to the purifier 6010, the compressed high temperature vapor may exit the compressor 6064 substantially in-line with the axis of the purifier 6010. After exiting the compressor 6064, the compressed vapor may follow a substantially straight path into the condenser 6076. To facilitate this, the condenser inlet fitting 6258 may have a center point that is substantially in-line with the axis of the purifier 6010. Such a straight flow path to the condenser 6076 may help minimize flow losses of the fluid exiting the compressor 6064.

[0105] 32 , an exploded view of the various components of the purifier 6010 is shown. As shown, the condenser inlet fitting 6258 may connect to the intermediate conduit 6270 through the wall of the vapor chest 6072. The condenser inlet fitting 6258 may include rounded or chamfered edges 6272 to facilitate mating of the condenser inlet fitting 6258 with the intermediate conduit 6270. A gasket member may be included to help create a seal at the interface between the condenser inlet fitting 6258 and the intermediate conduit 6270. The gasket member may be an elastomeric or flexible member in the shape of an O-ring or toroid ring.

[0106] One or more levels 6070A-C of the mist eliminator assembly 6062 may include a sleeve projection 6276 sized to receive a portion of the intermediate conduit 6270. The intermediate conduit 6270 may include a recessed region 6286 in its outer surface. The recessed region 6286 may be complementary in shape to a gasket member 6280 that may fit within the recessed region 6286. When assembled, the gasket member 6280 may be compressed between the inner surface of the sleeve projection 6276 and the outer surface of the intermediate conduit 6270. This compression may prevent liquid in a lower portion of the steam chamber 6072 from passing between the interior of the sleeve projection 6276 and the exterior of the intermediate conduit 6270 and entering the mist eliminator assembly 6062. The gasket member 6280 may also assist in positioning the mist eliminator assembly 6062.

[0107] The intermediate conduit 6270 may fit against and seal against the end of the condenser inlet 6274 . This seal may prevent flow from the vapor chest, which may contain concentrated blowdown, from entering the condenser inlet 6274. As shown, at least one gasket member 6282, 6284 may be included to help create a robust seal between the intermediate conduit 6270 and the condenser inlet 6274. In this exemplary embodiment, several gasket members 6282, 6284 are included to create a redundant seal. When assembled, high pressure compressed vapor from the compressor 6064 may enter the evaporator-condenser housing 6268 along a linear path formed by the condenser inlet fitting 6258, the intermediate conduit 6270, and the condenser inlet 6274 after passing through these components.

[0108] Referring now to FIGS. 33-34 , the condenser inlet 6274 may extend through the second tube sheet 6142B to the first tube sheet 6142A. The tube sheets 6142A,B, which may be made of a compressible material, may form a seal around the exterior of the sealing segment 6290 portion of the condenser inlet 6274. The portion of the condenser inlet 6274 that seals against the tube sheets 6142A,B may be a smooth, continuous length of tubing. Because the condenser inlet 6274 is hollow, an internal plug 6294 may be placed within the condenser inlet 6274 near the first tube sheet 6142A. This plug 6294 may create a seal that prevents fluid communication between the condenser 6076 and the sump 6052. The plug 6294 may be a disk that is welded or otherwise coupled within the condenser inlet 6274. Additionally, at least one drain port 6296 may be included adjacent plug 6294 to facilitate drainage of product process stream 6298 from condenser inlet 6274. Alternatively, condenser inlet 6274 may extend only through second tube sheet 6142B and only a small distance into the interior volume of condenser 6076. In such an embodiment, first tube sheet 6142A may include a solid section instead of a cavity that seals around sealing segment 6290 of condenser inlet 6274.

[0109] The condenser inlet 6274 may also include a windowed segment 6288. The windowed segment 6288 may be included between the sealing segments 6290 of the condenser inlet 6274. This windowed segment 6288 may include several windows 6292. The windows 6292 may function as a vapor flow diffuser and help create an even distribution of the high-pressure vapor (shown as stippled lines) entering the condenser 6076. The windows 6292 may be any shape, including, but not limited to, circles, rounds, ovals, ellipses, polygons, and stars. In this example, the windows 6292 are elongated rectangles with rounded corners. The windows 6292 may be included in several sets disposed at different locations throughout the windowed segment 6288. In the illustrated example, there are four sets evenly spaced from each other. Within each set, the windows 6292 may be positioned at substantially equal angular intervals from each other. The windows 6292 may be placed, for example, every 30 to 60 degrees (eg, every 45 degrees).

[0110] An alternative condenser inlet 6274 is shown in FIG. 35 . As shown, the condenser inlet 6274 includes a windowed region 6288 and a sealed region 6290. The window 6292 is round, generally circular in this example. Additionally, the condenser inlet 6274 includes a solid area 6300 without a window 6292. The solid area 6300 may be disposed within the condenser 6076 when the purifier 6010 is assembled. The windowed section 6288 is located in a portion of the compressor inlet 6274 proximal to the compressor 6064. Thus, the windowed section 6288 may be positioned such that it is the first portion of the condenser inlet 6274 within the condenser 6076 that receives high-pressure steam from the compressor 6064. A plug 6294 (see, e.g., FIG. 33 ) may be included at the transition between the windowed region 6288 and the solid area 6300.

[0111] Referring primarily to Figures 34 and 36, as the high pressure, high temperature vapor entering the condenser 6076 begins to condense, product process stream 6298 may begin to build up at the bottom of the condenser 6076. Additionally, latent heat of condensation may be transferred to the evaporator tubes 6140 to assist in the evaporation of the incoming raw water. A product storage tank 6012 may be included and may be attached to the evaporator-condenser housing 6268. The product storage tank 6012 may be attached to the evaporator-condenser housing 6268 via a product storage tank inlet 6302. The product storage tank inlet 6302 may be disposed adjacent to a product accumulation surface such that the product process stream 6298 may begin filling the product storage tank 6012 immediately after or simultaneously with the product water beginning to accumulate. In this example, the product accumulation surface is the first tube sheet 6142A.

[0112] As shown, a product level sensor 6078 may be included within the product storage tank 6012. The product level sensor 6078 may be a floating sensor and may include a float 6304 connected to an arm 6306 that displaces about a pivot point 6308. Similar to the blowdown level sensor 6074 (see, e.g., FIG. 16 ), the product level sensor 6078 may include a number of magnets 6310. As the level of liquid in the product storage tank 6012 rises and falls, the arm 6306 may rotate about the pivot point 6308 as the float 6304 is displaced. The position of the magnet 6310 may be tracked by a Hall effect sensor 6322 (see, e.g., FIG. 38 ) to determine the level of liquid in the product storage tank 6012.

[0113] The product storage tank 6012 is positioned such that the product level sensor 6078 can directly sense the liquid level in the product storage tank 6012 as well as in the condenser 6076. To facilitate this, the product level sensor 6078 may be positioned such that the swing range of the float 6304 passes above the product storage tank inlet 6302. The condenser 6076 may thus also serve as a product stream storage tank whose volume may be monitored by the product level sensor 6078. As such, the product storage tank 6012 may be described as an auxiliary product storage tank. In one embodiment, the swing range of the float 6304 may be selected such that the product level sensor 6078 can measure a volume of product in the condenser 6076 of between 4 and 10 L (e.g., 6 or 6.5 L).

[0114] The product storage tank 6012 may include a product outlet 6312 through which the product process stream may exit the product storage tank 6012. This outlet 6312 may be connected to a product flow conduit leading to the product heat exchanger 6008A, as described elsewhere herein. The exemplary outlet 6312 may be aligned with a bottom interior surface 6316 of the product reservoir 6012. The product reservoir 6012 may also include a vent port 6314. The vent port 6314 may allow gas to be displaced from the product reservoir 6012 as high-pressure steam from the compressor 6064 condenses in the condenser 6076 and begins to fill the product reservoir 6012. A condenser vent 6318 may also be included to allow excess pressure, volatiles, and non-condensable gases to escape from the condenser 6076 as needed. Both the vent port 6314 and the condenser vent 6318 may be attached to a vent channel 6320.

[0115] Referring now to FIG. 37 , a perspective view of the system 6000 is shown. Fluid lines other than the vent flow path 6320 are hidden in FIG. 37 for clarity. Vent gas from the evaporator-condenser housing 6268 and the product storage tank 6012 may travel along the vent flow path 6320 to a pressure relief assembly 6324. The pressure relief assembly 6324 may include a pressure relief valve 6326. The pressure relief valve 6326 may be a fail-safe valve that opens if an overpressure condition occurs within the purifier 6010. If the pressure relief valve 6326 is forced open, the vent gas may vent through the vent flow path 6320 attached to the outlet of the pressure relief valve 6326. The pressure relief valve 6326 may be set to open at a predetermined pressure, which may be at or about 15 psig in some particular examples. The pressure relief assembly 6324 may also include a vacuum breaker 6330. The vacuum breaker 6330 may allow the purifier 6010 to equalize with ambient pressure upon cooling. The vacuum breaker 6330 may include, for example, a check valve that allows the purifier 6010 to maintain pressure during operation, but may draw in ambient air if the interior of the purifier 6010 drops below ambient pressure.

[0116] From the pressure relief assembly 6324, the gases may travel to a vent flow path 6320 that extends through the blowdown heat exchanger 6008B. In some embodiments, a vent valve 6328 may be included to control the flow of gases into the blowdown heat exchanger 6008B. The gases may pass through the blowdown heat exchanger 6008B countercurrently to the raw water entering the system 6000. These gases may transfer thermal energy to the incoming raw water, warming the raw water. Cooling these gases may cause some of the gases to condense as they pass through heat exchanger 6008B, making them easier to process.

[0117] 38 and 39, two perspective views are shown detailing the product flow path 6322 of the exemplary system 6000. For clarity, only the product flow path 6322 is shown in FIGS. 38 and 39; the flow paths of the raw water and other process streams are not shown. As shown, the product water leaving the product storage tank 6012 can flow to both the product heat exchanger 6008A and the bearing feed pump 6080. In this exemplary embodiment, a branch fitting 6332 is included to split the product stream for this purpose. The product water flowing through the heat exchanger 6008A can transfer heat to the incoming raw water before exiting the heat exchanger 6008A at a reduced temperature. The cooled product water can exit the product heat exchanger through the product flow path 6322. The bearing feed pump 6080 can pump a portion of the product water leaving the product storage tank 6012 to the compressor 6064. The bearing feed pump 6080 may be a solenoid pump. As described elsewhere herein, the product water may be used to lubricate the impeller bearings.

[0118] Referring now primarily to FIGS. 40-41 , the cooled product process stream exiting the product heat exchanger 6008A may proceed to a sensing manifold 6340. The product may enter the sensing manifold through an inlet port 6342 and flow along an internal flow path that communicates with one or more sensors 6082A, 6082B. In this exemplary embodiment, two sensors 6082A, 6082B are shown, but other embodiments may include additional sensors. In some embodiments, a redundant set of identical sensors 6082A, 6082B may be included. At least one sensor 6082A, 6082B may be a conductivity sensor or a conductivity-temperature sensor. Other sensor types that may provide data signals related to water quality, such as turbidity, pH, oxidation-reduction potential, TDS, analyte sensors, TOC, etc., may also be included.

[0119] The sensing manifold 6340 may also include one or more valves 6344 that may be operated by the controller 6034 (see, e.g., FIG. 2) to direct the product process flow based on data provided from the at least one sensor 6082A, 6082B. If the water quality (e.g., conductivity value) is outside a threshold, a valve leading to a drain flow path 6346 may be opened. If the water quality (e.g., conductivity) complies with a predetermined threshold, the controller 6034 (see, e.g., FIG. 2) may operate one or more valves 6084, 6086 to direct the product process flow to a medical system flow path 6348. The valves 6084, 6086 may be operated by the controller 6034 based on signals the controller 6034 receives from the medical system 6004 (see, e.g., FIG. 2).

[0120] 42-43, the cooled vent and blowdown streams exiting the blowdown heat exchanger 6008B may travel to a mixing tube 6350. In some embodiments, the vent stream may not be routed through the blowdown heat exchanger 6008B but may instead be routed directly to the mixing tube 6350. As shown, the mixing tube 6350 includes a port 6352 to which the blowdown flow conduit 6162 is attached. The mixing tube 6350 also includes a port 6354 to which the vent flow path 6320 is attached. The flow into the mixing tube 6350 may be controlled by valves 6356, 6358, which control communication from the blowdown port 6352 and the steam port 6354, respectively, to the interior volume of the mixing tube 6350. An additional port 6360 connected to the raw fluid line 6126 may also be included. After mixing, the fluid may exit the mixing barrel 6350 via an outlet port 6362 which may be connected to a drain conduit 6364 .

[0121] The mixing barrel 6350 may be used to combine several process streams from the clarifiers. For example, a vent stream may be combined with a cooled blowdown stream to ensure that any hot gases that have passed through the blowdown heat exchanger 6008B are quenched to a relatively low temperature. As shown, the mixing barrel 6350 also includes at least one sensor 6096, which in this exemplary embodiment may be a temperature sensor. The controller 6034 (see, e.g., FIG. 2 ) may monitor data from the sensor 6096 and determine whether the temperature within the internal volume of the mixing barrel 6350 is below a predetermined threshold. If the interior of the mixing barrel 6350 is too hot, cooler raw water may enter the mixing barrel through a source shunt port 6360. A shunt valve 6100 (see, e.g., FIG. 2 ) may be included upstream of (or attached to) the mixing barrel 6350 to control the flow of raw water into the mixing barrel 6350. In this exemplary embodiment, mixing barrel 6350 also includes a vacuum breaker 6330. The vacuum breaker 6330 may be included on mixing barrel 6350 instead of being included on pressure relief assembly 6324 as previously described.

[0122] 44 , a portion of the clarifier 6010 may be mounted on a pivot 6365. The pivot 6365 may allow the mounted portion of the clarifier 6010 to be easily removed from the clarifier 6010 for cleaning, replacement, to better access other portions of the clarifier 6010, or for other maintenance purposes. The pivot 6365 may allow the evaporator-condenser housing 6268 to be removed for overhaul cleaning operations such as, for example, inspection or descaling procedures. In this example, the evaporator-condenser housing 6268 and the sump 6052 are both configured for removal by rotation about the pivot 6365.

[0123] 44, the pivot shaft 6365 is attached to a support plate 6370. The support plate 6370 may extend below the sump 6052 to support removable components. In some embodiments, the support plate 6370 may be fastened to the sump 6052 to aid in maintaining and positioning removable components on the support plate 6370. Depending on the material of the support plate 6370 and the weight of the removable components, support members 6372 may be included to strengthen the support plate 6370.

[0124] The purifier 6010 may be provided in several sections (e.g., first and second) that are coupled to one another via fasteners in a first state. The fasteners may include at least one clamp. In this exemplary embodiment, the fasteners are shown as band clamps 6374. Referring now also to FIGS. 45-46 , in a second state, when the band clamps 6374 coupling the evaporator-condenser housing 6268 to the steam chest 6072 are removed, the combined weight of the evaporator-condenser housing 6268, sump 6052, and attached components may be supported by the pivot shaft 6365. As best shown in the exploded view of FIG. 44 , a biasing member 6376 may be included in the pivot shaft 6365. As a result of the band clamps 6374 being removed, the biasing member 6376 may be transitioned to an energy-storing state, such as a compressed state (best shown in FIG. 46 ). When the biasing member 6376 is in a compressed state, the pivot shaft 6365 and removable component may be displaced away from the steam chest 6072. The amount of displacement may be selected to provide clearance for the top of the condenser inlet 6274 as the removable component is rotated away from the rest of the purifier 6010. The displacement path of the support plate 6370 and attached component may be linear, but need not be in all embodiments. Specifically, the displacement path may be along or parallel to the axis of the pivot shaft 6365. In this exemplary embodiment, the biasing member 6376 may be a corrosion-resistant gas spring. Other types of biasing members 6376 may also be used, such as coil springs, spring washers, Belleville springs, compressible elastomers, bladders, or any other suitable biasing member.

[0125] Once the biasing member 6376 has transitioned to the compressed or energy stored state, and then, referring also to FIG. 47 , the removable components (in this example, the sump 6052 and the evaporator-condenser housing 6268) may be rotated about the axis 6378 of the pivot 6365. This allows the removable components to be rotated away from the rest of the purifier 6010 and disengaged from the pivot plate 6370. If these components are to be removed for overhaul cleaning, a spare replacement set of components may be placed on the pivot plate 6370 and rotated back into place, minimizing downtime. After being rotated back into place, the biasing member 6376 may assist in reassembly as it helps lift the replacement set of components into place.

[0126] D2 embodiment 48-49, an exemplary system 6000 similar to that shown schematically in FIG. 3 is shown. As shown, the system 6000 includes a housing 6550. The housing 6550 is generally rectangular in shape. As shown, the front of the housing 6550 includes two doors 6552A, 6552B. Additionally, a sampling well 6554 is included on the front of the housing 6550. The sampling well 6554 may include a perforated tray 6556 in which a cup, glass, or similar container may be placed while water is dispensed from the sampling port 6038 (see, e.g., FIG. 3) of the system 6000. Any separated sample fluid may collect in a catch basin located below the perforated tray 6556. An LED or similar light may be included to illuminate the sampling well 6554. In this exemplary embodiment, sample may be dispensed via depression of a button 6558, which may be backlit in some embodiments.

[0127] The rear of the housing 6550 can include an opening through which a source connector 6560 of a raw fluid line extends. A drain connector 6562 can also extend through the rear of the housing 6550. The source connector 6560 and the drain connector 6562 may each be a quick connect fitting in some embodiments. Power and data connections 6561 may also be provided through the rear of the housing 6550.

[0128] The top of the housing 6550 is generally flat and may include an outlet line 6564 for purified water. As shown, this outlet line 6564 may be insulated to help maintain the temperature within the line and protect it from contact with the user when it is very hot. A medical system 6004 or other point-of-use system or device may be disposed on the top of the housing 6550 and in fluid communication with the outlet line 6564. In some embodiments, the medical system 6004 or other system or device may be fixed (e.g., bolted, clamped, or otherwise mechanically held). Alternatively, such a system or device may passively rest on top of the housing 6550. A shelf 6566, platform, container, or similar structure may be coupled to the housing 6550 for storage. In some embodiments, the shelf 6566 or container may hold components utilized by the medical system 6004 or other device during use (e.g., an acid reservoir and bicarbonate reservoir for a hemodialysis machine).

[0129] The housing 6550 may include several internal compartments, which may be insulated from one another. For example, the housing 6550 may include a hot compartment housing 6102 in which the high temperature components of the system 6000 are housed and insulated from the rest of the system 6000. Another compartment of the housing 6550 may be a cold compartment housing 6103A,B that maintains a relatively low temperature compared to the hot compartment housing 6103. The purifier 6010 (see, e.g., FIG. 52) and heat exchangers 6008A,B (see, e.g., FIG. 52) may be included in the hot compartment housing 6102. In some embodiments, the purifier 6010 and heat exchangers 6008A,B are 200 in. 2 Less than (e.g., 180 in 2 The height of the purifier 6010 may be less than 30 inches (e.g., 26.5 inches or less).

[0130] Referring now also to FIG. 50 , a front view of the housing 6550 is shown with the doors 6552A,B removed. As shown, a first filter 6006A and a second filter 6006B may be included behind the doors 6552A,B. A sampling port 6038 may be disposed intermediate the two filters 6006A,B such that a sample represents the filtration capacity of only the first filter 6006A. In other embodiments, an additional sampling port 6038 may be included, capable of collecting samples downstream of both the first and second filters 6006A,B. The filters 6006A,B may be identical, and in some embodiments may be 5-6 L activated carbon filters. The filters 6006A,B may be placed after 6552A,B to facilitate replacement of the filters 6006A,B after a predetermined life span or after the controller 6034 determines that the filters 6006A,B need to be replaced. The filtered source line 6568 may be routed from the cold compartment housing 6103B to the cold compartment housing 6103A through a cold compartment channel 6570. The channel 6570 may be routed under or over a portion of the compartment of the hot compartment housing 6102.

[0131] 51 , a rear perspective view of the system 6000 is shown with the rear panel of the housing 6550 removed. As shown, the various manifolds 6572, 6574, 6576, 6578, as well as the mixing reservoir 6092, may be included in the cold compartment housing 6103B. In other embodiments, all of the manifolds 6572, 6574, 6576, 6578 may be combined into a single, integral manifold. The manifolds 6572, 6574, 6576, 6578 are described in more detail later in this specification. A catch basin 6587 may be included below the manifolds 6572, 6574, 6576, 6578 and may include a leak sensor (not shown). The electronics for the system 6000 may also be included in the cold compartment housing 6103B. In this exemplary embodiment, the electronics are split between the first and second electronics housings 6046A,B. In other embodiments, a single housing may be used. Various data and power cables may be routed through passages 6580 in a portion of insulating material 6584 disposed within the wall of the hot compartment housing 6102. This portion of insulating material 6584 may be an insulating foam or elastomeric material that is compressible in some embodiments. This portion of insulating material 6584 in this exemplary embodiment is shown as a plug-like structure disposed within an opening from the interior of the cold compartment housing 6103 to the hot compartment housing 6102. These portions of insulating material 6584 may be in a compressed state against the walls of the opening in the hot compartment housing 6102. Additionally, the through passage 6580 may be compressed around the cables (not shown) that extend through it, which may help establish a tight seal between the hot section housing 6102 and the cold section housing 6103B. The lines leading to the air filter 6093 may also pass through the wall of the hot section housing 6102 to reach the air filter 6093.

[0132] 52 and 53, a perspective view of the system 6000 is shown with the housing 6550 removed. For clarity, only the fluid lines carrying the raw water are shown in FIGS. 52 and 53. The raw water may enter the system 6000 at a source connector 6560 through a source connection line 6582. In this exemplary embodiment, and with reference also to FIGS. 54 and 55, the source connector 6560 is included in an inlet manifold 6572. The inlet manifold 6572 may also include a flow control valve 6032, a check valve 6030 (see, e.g., FIG. 3), and one or more sensors. In this exemplary embodiment, a temperature sensor 6042 and a pressure sensor 6036 are included in the inlet manifold 6572. In other embodiments, additional sensors that sense various properties of the incoming raw water, or sensors that provide redundancy to those shown, may be included.

[0133] From the source manifold 6572, the raw fluid may flow through filters 6006A,B and may be sampled through sampling port 6038, depending on the mode or state of the system 6000. After filtration, the raw water may flow to a post-filter raw fluid connector 6568 included in a product heat exchanger manifold 6578. Referring now also to FIG. 55, the product heat exchanger manifold 6578 may include a pressure regulator 6040 that may control the raw water pressure to a predetermined value (e.g., 10-30 psig). A post-filter pressure sensor 6044 may also be included in the product heat exchanger manifold 6578. Readings from pressure sensor 6036 (see FIG. 54) and pressure sensor 6044 may be compared by controller 6034 to determine the pressure drop across the filters 6006A,B. This pressure drop may be compared to a predetermined range of expected values. This may allow the controller 6034 to detect clogged filters or unexpectedly low or high pressure drop scenarios. From the product heat exchanger manifold 6578, the raw fluid may flow through a source line 6590 to the product heat exchanger 6008A. A source proportioning control valve 6050A for raw water flow to the product heat exchanger 6006A may also be disposed within the product heat exchanger manifold 6578.

[0134] The flow path to the blowdown heat exchanger 6008B may extend to the electronics housing 6046A of the system 6000 (see, e.g., FIG. 51 ) so that the source flow may serve to cool the electronics housing 6046A. Alternatively or additionally, the raw water en route to the product heat exchanger 6008A may be routed such that it is in heat exchange relationship with the electronics in the electronics housing 6046A. In the example shown in FIGS. 52 and 53 , the electronics cooling line 6592 is routed such that it bends back on itself in two places before connecting to the blowdown heat exchanger manifold 6574. The raw fluid may flow through the source line 6590 from the blowdown heat exchanger manifold 6574 to the blowdown heat exchanger based on operation of a source proportioning control valve 6050B disposed in the blowdown heat exchanger manifold 6574. A source diversion valve 6100 may also be included in the blowdown heat exchanger manifold 6574 to allow raw water to flow into the mixing reservoir 6092, which in this exemplary embodiment is attached directly to the blowdown heat exchanger manifold 6574.

[0135] As the raw water passes through the heat exchangers 6008A,B, it may be heated by the various process streams of the clarifier 6010, which are at a higher temperature compared to the incoming raw water. The various process streams may then be cooled. After the raw fluid is passed through the heat exchangers 6008A,B, it may be combined into a single stream at a flow coupler 6594 (e.g., a Y-fitting, T-fitting, U-fitting, etc.) and piped to the sump 6054 of the clarifier 6010. The sump 6054 may be a metal cast component in some embodiments.

[0136] Referring now also to FIG. 56, a diagram of exemplary heat exchangers 6008A, B is shown. The heat exchangers 6008A, B may each be configured as a spiral of piping through which the raw water and various process streams of the system 6000 may flow. The spiral formed by each of the heat exchangers 6008A, B may have a substantially constant radius and pitch. At the ends of the heat exchangers 6008A, B, the pitch may increase as shown. The heat exchangers 6008A, B may be configured concentrically, with one of the heat exchangers 6008A, B having a smaller radius and positioned inside the other. In the exemplary embodiment shown in FIG. 56, the blowdown heat exchanger 6008B is positioned inside the product heat exchanger 6008A. Each of the heat exchangers 6008A, B may be disposed around the clarifier 6010 to improve the compactness of the system 6000. The fluid path lengths in the product heat exchanger 6008A and the blowdown heat exchanger 6008B may be substantially equal. In some embodiments, the heat exchanger spirals may be formed using the exterior surface of the clarifier 6010 as a mold. In such embodiments, the heat exchangers 6008A,B may contact the sidewalls of the clarifier 6010.

[0137] A cross-sectional view of a portion of exemplary heat exchangers 6008A,B is shown in FIG. 56A. As shown, each heat exchanger 6008A,B includes a large-diameter source flow conduit 6596A,B that forms the exterior surface of the heat exchanger 6008A,B. Within the source flow conduits 6596A,B are conduits through which process streams from the water clarifier 6010 are carried. The product water heat exchanger 6008A in this exemplary embodiment includes three product flow conduits 6598 disposed within its source flow conduit 6596A. The exemplary blowdown heat exchanger 6008B includes a single internal flow conduit 6599 within its source flow conduit 6596B. This internal flow conduit 6599 may carry either a concentrate or blowdown process stream from the clarifier 6010. In some embodiments, additional flow conduits may be included therein. Where the heat exchangers 6008A,B are concentric and nested inside one another, the innermost heat exchanger may include a layer of insulation 6597. This may help prevent heat transfer to and from the purifier 6010. In other embodiments, both heat exchangers 6008A,B may include a layer of insulation 6597.

[0138] heat exchanger terminator An exemplary terminator for the product heat exchanger 6008A is shown in FIG. 57. The product terminator 5800 seals the outer tube 6596A and provides a fluid conduit from the outer tube 6596A to the side port 5802. The product terminator 5800 also seals multiple inner tubes 6598 and provides a fluid conduit from the inner tubes to the end port 5804. In one embodiment, there are three inner tubes 6598. In another embodiment, there may be two, four, five, six, or more inner tubes 6598. It is very important that the product terminator 5800 maintains separation between the fluid in the outer tube 6596A and the fluid in the inner tubes 6598. In some cases, the water entering the outer tube 6596A is contaminated source water, and the liquid entering the inner tube 6598 is distilled product water. The product terminator 5800 is designed to prevent contamination of the product water using multiple seals, as described in detail below. The product terminator 5800 also provides a mechanical connection to the outer tube and / or inner tube. The product terminator grips and seals the outer tube by turning or tightening the manifold nut 5808 onto the terminator body 5801. The terminator body 5801 includes wrench flats 5805, which allow counter torque to be applied to the terminator body when either manifold nut 5808, 5806 is tightened. The product terminator 5800 may be manufactured from a material compatible with high-temperature water and moderate pressures of <30 psi. Materials include, but are not limited to, stainless steel, brass, titanium, polysulfone plastic (PSU), polyphenylsulfone such as Radel, polyphenylene sulfide plastic (PPS) such as Ryton or Fortron, and other high-temperature plastics. In a preferred embodiment, the plastic is slightly transparent.

[0139] The cross-sectional view of product terminator 5800 shown in Figure 57B best illustrates the interaction of the various elements of the product terminator. A cross-sectional view of Figure 57B is shown in Figure 57A. The individual elements of product terminator 5800 are clearly shown in the exploded view of Figure 57C.

[0140] The outer tube 6596A is gripped and sealed within the product terminator by the interaction of the manifold nut 5808, retaining ring 5812, wedge 5814, O-ring 5818, and body 5801. The outer tube 6596A slides into the assembled product terminator 5800, over the retaining ring 5812 and O-ring 5818, until the outer tube 6596A reaches an internal stop 5803 in the body 5801. Insertion occurs when the manifold nut 5808 is loosened. The retaining ring 5812 is shaped and sized so that its undeformed inner diameter is larger than the outer diameter of the outer tube 6596A. The larger inner diameter of the retaining ring 5812 reduces scratches / gouges / scratches on the outer tube, which could cause leakage past the O-ring 5818. The internal stop 5803 is positioned so that the end of the outer tube 6596A can be viewed through the side port 5802 when the outer tube 6596A is fully and properly inserted. This viewing ensures that the outer tube 6596A is fully seated and sealed by the O-ring 5818. Once the outer tube is fully inserted, the manifold nut 5808 is tightened onto the body 5801. Tightening the manifold nut 5808 forces the internal teeth of the retaining ring 5812 against the wedge ring 5814, which in turn deflects the teeth of the retaining ring 5812 inward to engage the outer surface of the outer tube 6596A. The engaged teeth of the retaining ring 5812 prevent the outer tube from slipping out of the product terminator 5800.

[0141] Continuing with reference to FIGS. 57B and 57C, O-ring 5818 is placed in an appropriately sized gland in body 5801, sized to compress O-ring 5818 to form a radial seal against the outer surface of outer tube 6596A. The O-ring is made of a material suitable for the high temperatures expected in the product fluid exiting the purifier. The O-ring may be made from a list of materials including, but not limited to, Buna-N, silicone, and EPDM. Wedge 5814 also serves to define a gland for O-ring 5818. The removable wedge simplifies the process of molding body 5801 and inserting O-ring 5818. In another embodiment, wedge 5814 is part of body 5801.

[0142] 57B and 57C, the plurality of inner tubes 6598 extend beyond the end of the outer tube 6598A long enough to reach the product manifold 5816 of the end fitting 5804. In preferred embodiments, the end fitting 5804 is sufficiently transparent to allow visualization of all of the plurality of inner tubes 6598 extending beyond the O-ring cap 5830. In some embodiments, the O-ring cap 5830 is separate from the end fitting 5804, allowing the end fitting to be rotated to a preferred orientation before the manifold nut 5806 is tightened.

[0143] The double seal formed at each inner tube 6598 by inner tube seals 5820 and 5822, in combination with leak path 5803 to ambient pressure, ensures that raw water in outer tube 6596A cannot contaminate the product water in product manifold 5816. The outer surface of each inner tube 6598 is sealed by inner tube seals 5820 and 5822. In one embodiment, inner tube seal 5820 is an O-ring that forms a radial seal between the outside of each inner tube 6598 and body 5801. In one embodiment, inner tube seal 5822 is an O-ring that forms a radial seal between the outside of each inner tube 6598 and flow separator 5832. The space between the two inner tube seals 5820, 5822 is a dry manifold 5828, which is fluidly connected to ambient air via leak port 5803 ( FIG. 57 ). The dry manifold 5828 is defined by the body 5801, the dry separator 5832, the two inner tube seals 5820, 5822, and the seal 5826. In one embodiment, the seal 5826 is an O-ring that forms an end seal. The dry manifold 5832 includes a fluid path from the outside of the inner tube 6598 between the inner tube seals 5820, 5822 to the dry manifold 5828. Any fluid that leaks past either inner tube seal will then flow into the dry manifold 5828 at atmospheric pressure and exit through the leak port 5803. The static pressure in the inner and outer tubes is greater than atmospheric pressure, so any fluid that leaks into the dry space cannot leak out into the outer tube 6598A or the product manifold 5816.

[0144] 57B and 57C , in one embodiment, seals 5820 and 5822 are O-rings sized to form a radial seal on the exterior of inner tube 6598. Body 5801 and flow separator 5832 define the outer diameter of the glands for O-rings 5820 and 5822 to create a radial seal on the exterior of each inner tube 6598. In this embodiment, O-ring 5820 is retained by flow separator 5832, and O-ring 5822 is retained by tube cap 5830. In one assembly embodiment, the inner tube slides through the assembled product terminator 5800, past seals 5820 and 5822, and ultimately extends past tube cap 5830. Manifold nut 5806 may be loose, allowing end connector 5804 to be oriented as desired. Finally, tighten the manifold nut 5806 to secure the end connector in place and ensure that the flow separator 5832 and tube cap 5830 are completely sealed to the body 5801 and flow separator 5832, respectively.

[0145] 57D-57E, a concentrate terminator 5850 terminates a concentrate heat exchanger 6008B having a single tube 6599 that carries concentrate within an outer tube 6596B. The outer tube slides over a barb 5856 on the body 5860. In some embodiments, the barb provides a liquid seal on the inner diameter of the outer tube 6596B. In some embodiments, an O-ring 5864 provides a liquid seal or pre-liquid seal on the inner diameter of the outer tube 6596B. In some embodiments, a ring or tube clamp 5862 secures the outer tube 6596B to the barb 5856. The concentrate terminator 5850 may be fabricated from a material that is compatible with high temperature water and moderate pressures of <30 psig. Materials include, but are not limited to, stainless steel, brass, titanium, polysulfone plastic (PSU), polyphenylsulfone such as Radel, polyphenylene sulfide plastic (PPS) such as Ryton, Fortron, and other high temperature plastics. In a preferred embodiment, the plastic is slightly transparent.

[0146] The inner tube 6599 extends beyond the end of the outer tube 6596B far enough to pass through the stopper 5866. In a preferred embodiment, the extension of the inner tube 5866 beyond the stopper 5866 is visible through the wall of the end connector 5852. The concentrate terminator 5850 seals both the raw water in the outer tube 6596B and the concentrate in the inner tube 6599 by axially compressing the stopper 5866. When the stopper 5866 is axially compressed, it seals the raw water at 5865 between the stopper 5866 and the outside of the inner tube 6599, and between the stopper 5866 and the body 5860. The concentrate is sealed at 5853 between the stopper 5866 and the end connector 5852. A dry manifold 5861 is formed by seals 5853, 5865, manifold nut 5858, and stopper 5866. Leak port 5857 allows any leakage past seals 5853 and 5865 to flow out of the connector, reducing contamination of one fluid with another.

[0147] Referring primarily to FIG. 59, which is a cross-section of the exemplary clarifier 6010 taken along line 59-59 in FIG. 58, after the raw water travels into the sump 6052, the water may begin to fill several evaporator tubes 6140 as well as the evaporator reservoir 6015. The evaporator reservoir 6015 may be disposed laterally relative to the evaporator 6060 and may have a cylindrical shape. In this exemplary embodiment, the evaporator reservoir 6015 has a greater height than the evaporator 6060. The evaporator reservoir 6015 may be in fluid communication with the sump 6052 through an evaporator reservoir inlet 6604 extending to the sump 6052. In this example, the evaporator reservoir inlet 6604 is located at a first end portion of the evaporator reservoir 6015. The evaporator reservoir inlet 6604 may connect to the sump 6052 at a point where raw water may begin to proceed to the evaporator reservoir 6015 shortly after it begins to be introduced into the sump 6052. This may allow the fluid level in the evaporator reservoir 6015 to be substantially the same as the fluid level in the evaporator 6060. A second, opposite end of the evaporator reservoir 6015 may include a vent port attached to a vent line that is in fluid communication with the steam chest 6072 via a port 6612 in the blowdown reservoir 6014 (see, e.g., FIG. 65 ).

[0148] The evaporator reservoir 6015 may include a water level sensor 6073 that measures the liquid level in the evaporator 6060 based on the displacement of a float 6606 in the evaporator reservoir 6015. The displacement of the float 6606 may displace a wiper of a potentiometer in some embodiments. In other embodiments, the float 6606 may include one or more magnets whose displacement is tracked by a Hall Effect sensor array. Alternatively, the sensor may be an XM-XT (e.g., XM-700) series sensor available from Gems Sensors Inc. of One Cowles Road, Plainville, Connecticut. Any other suitable sensor may also be used.

[0149] The evaporator reservoir 6015 may be arranged so that, at least during a particular state or mode of operation of the purifier 6010 (e.g., a fill state or a drain state), a portion of the interior volume of the evaporator reservoir 6015 is flush with any point within a controllable or expected range of liquid level values ​​in the evaporator 6060. The displacement range of the float 6606 may be selected to accommodate sensing across this range. In some embodiments, the displacement range of the float 6606 may be only a portion of the extension of the evaporator reservoir 6015. For example, the displacement range of the float 6606 may be only about half (40%-60%) of the extension or height of the evaporator reservoir 6015. In this exemplary embodiment, the displacement range is generally limited to the top half of the evaporator reservoir 6015. In an embodiment, the displacement range may extend from the top portion of the evaporator reservoir 6015 to at least the midpoint of the evaporator reservoir 6015, but not more than 70% of the extension range of the evaporator reservoir 6015. In some embodiments, the controller 6034 may receive a data signal from the level sensor 6073 in the form of a percentage of the displacement of the float 6606 along the entire displacement range of the float 6606.

[0150] During purified water production modes or states, steam bubbles may be present in the evaporator tubes 6140, and a significant amount of splashing may typically occur due to violent boiling. As a result, there may be no clear or discernible liquid level in the evaporator 6060 of the purifier 6010. Instead, the liquid level may be non-uniform and highly dynamic. During such states, the evaporator water level sensor 6073 may not be able to measure the liquid level in the evaporator 6060. Instead, the evaporator water level sensor 6073 may be used to monitor other characteristics that may be useful in controlling the operation of the system 6000. For example, data regarding the height of a relatively calm water column that may exist in the evaporator storage tank 6015 may be output by the evaporator water level sensor 6073. During operation, the evaporator water level sensor 6073 may operate similarly to a liquid column gauge. The height of the water column read by the evaporator water level sensor 6073 may vary based, at least in part, on the pressure of steam present in the evaporator 6060 and the steam chamber 6072. The water column height read by the evaporator water level sensor 6073 may also vary based, at least in part, on the average phase change position of the fluid within the evaporator tubes 6140. In some embodiments, the water column height output from the evaporator water level sensor 6073 may be monitored during production of purified water. If the water column begins to displace from the target position, the controller 6034 of the system 6000 may increase power to at least one of the heater 6054 and the compressor 6064, perhaps proportional to the rate at which the water column is displacing. Alternatively or additionally, the controller 6034 may reduce the amount of raw water delivered to the clarifier 6010 by lowering the duty cycle of any source flow proportioning valves 6050A, B. Again, this duty cycle change may be made proportional to the rate of displacement of the water column level. During production of purified water, the water column may be 50-60% of the height of the evaporator 6060. In an embodiment where the displacement range of the evaporator water level sensor 6073 is limited to the top half of the evaporator reservoir 6015, the controller may target a displacement of the float 6606 of approximately 10% from the bottom of its displacement range.

[0151] Referring now to Figures 59A-59D, the product and evaporation water level sensors may include removable sensors to facilitate maintenance and reduce liquid leak paths. The water level sensor includes a reservoir 5928 through which liquid can flow in and out through one or more bare pipe fittings 5904, 5908, 5910, which are connected to the purifier via a fluid fitting 5906. In one embodiment, the fluid fitting 5906 is a sanitary fitting. The fluid fitting 5906 should be large enough so as not to restrict the flow of water or air between the evaporator or condenser and the reservoir 5928. In one embodiment, the reservoir 5928 is a weldment comprising at least an outer cylinder 5914 and an inner cylinder 5916, and is watertight except for the ports 5904, 5908, 5910 and the fluid fitting 5906. The reservoir further includes a float 5920 that rises and falls within the reservoir with the water level and is guided by the inner cylinder 5916. The float 5920 has a permanent magnet. The linear sensor 5912 generates an electrical signal based on the position of the float 5920. The linear sensor 5912 slides into the inner cylinder 5916 and is mechanically connected to the top 5924 of the reservoir. In one embodiment, the linear sensor 5912 is a printed circuit board 5922 with a series of magnet-activated reed switches that respond to the presence of a magnet. The linear sensor 5912 may include other technologies, such as Hall sensors or 3D Hall sensors, to detect the location of the magnet within the float 5920. The removable linear sensor 5912 can be removed for maintenance and repair without draining the system. The reservoir weldment better protects the linear sensor from hot water or steam from the evaporator or condenser.

[0152] Referring now primarily to FIG. 60 , the evaporator tubes 6140 may extend from the volume of the sump 6052 through the condenser 6076 to the volume of the vapor chest 6072. The first and second tube sheets 6142A, B may include receiving holes 6144 for receiving each end of the evaporator tubes 6140. The tube sheets 6142A, B may hold the evaporator tubes 6140 in a generally evenly spaced pattern within the volume of the condenser 6076. In this exemplary embodiment, the tube sheets 6142A, B may be constructed from a metallic material that is brazed to connect with the evaporator tubes 6140, preventing fluid communication between the evaporator tubes 6140 and the interior volume of the condenser 6076. The second tube sheet 6142B may form the bottom wall of the vapor chest 6072. The use of metal tube sheets 6142A, B may help improve the compactness of the purifier 6010.

[0153] In this exemplary embodiment, fewer than 80 (specifically, 76) evaporator tubes 6140 are included. Other embodiments may include a greater or lesser number of evaporator tubes 6140. Each evaporator tube 6140 may have a substantially equal diameter, between 6 and 12% (e.g., about 8%) of the diameter of the condenser 6072. In some embodiments, the evaporator tubes 6140 may not all be of equal diameter. The evaporator tubes 6140 may occupy between 35 and 65% (e.g., about 49.5%) of the interior volume of the condenser 6076. The material from which the evaporator tubes 6140 are constructed may vary depending on the embodiment, but a material with high thermal conductivity may be used. In embodiments in which the evaporator tubes 6140 are brazed to the tube sheets 6142A, B, the materials selected for the evaporator tubes 6140 and the tube sheets 6142A, B may be any suitable material suitable for such a brazing operation. In another embodiment, the evaporator tubes 6140 may be welded to the tube sheet 6142A. The holes in the tube sheet 6142A may be formed with a flange or collar using a punch, which may facilitate welding the evaporator tubes 6140 to the formed flange of the tube sheet 6142A. The evaporator tubes 6140 may be laser welded to the formed flange of the tube sheet 6142A. In some embodiments, stainless steel may be used. In some embodiments, as shown in FIG. 60, a sleeve 6688, which provides part of the path from the compressor 6064 (see, e.g., FIG. 3) to the condenser 6076, may also be brazed in place to one of the tube sheets 6142A,B.

[0154] The evaporator tubes 6140 may include filler elements that fill a percentage of the cross-sectional area of ​​each (or possibly only some) of the evaporator tubes 6140. In this exemplary embodiment, the filler elements are depicted as substantially cylindrical bars 6600 that include several ridges or other protrusions 6602 on the exterior of the bars 6600. These ridges 6602 may aid in centering the bars 6600 within the evaporator tubes 6140. This may encourage a thin layer or film of source fluid (in this example, a thin annulus) to exist between the exterior of the filler element and the interior surface of the evaporator tube 6140 within which the filler element is disposed.

[0155] 61 and 62, a ridge 6602 disposed on the end of the bar 6600 may rest on the tube sheet 6142B that defines the bottom of the steam chest 6072. Alternatively, the ridge 6602 may rest on the upper edge of the evaporator tube 6140. This ridge 6602 may keep the bottom of the bar 6600 hanging above the bottom of the sump 6052. In some embodiments, the ridge 6602 may keep the bottom of the bar 6600 within the evaporator tube 6140. As shown in FIG. 61, an insulating layer 6605 may be included in some embodiments. The insulating layer 6605 may be placed around the condenser 6076. Insulating layer 6605 may insulate purifier 6010 from heat exchange with heat exchangers 6008A, B in embodiments where heat exchangers 6008A, B are wrapped directly around the exterior of purifier 6010 as they are wound in their respective spirals. Other embodiments may be similarly insulated.

[0156] Referring now primarily to FIGS. 63-66 , as heat from the heating element 6054 (see, e.g., FIG. 3 ) and condensing steam in the condenser 6076 evaporate the raw water, a blowdown process stream or condensate may be produced. The blowdown process stream may fill or splash a portion of the volume of the steam chamber 6072 due to vigorous boiling. As shown, a blowdown or condensate storage tank 6014 may be attached to the side of the steam chamber 6072. In this exemplary embodiment, the longitudinal axis of the blowdown storage tank extends alongside, but does not pass through, the evaporator 6060. A closed water passage 6610 may extend from the steam chamber 6072 to form a first portion 6624 of an inlet path 6614 to the blowdown storage tank 6014. This water passage 6610 may be a cast component. The water passage 6610 may be coupled to a housing 6616 that defines a portion of the interior volume of the blowdown storage tank 6014. In this exemplary embodiment, the housing 6616 is a substantially cylindrical body or tubular structure that extends downwardly from the waterway 6610. An outlet port 6618 may be included at the bottom of the blowdown reservoir 6014 so that blowdown fluid may be withdrawn from the clarifier 6010 as regulated by a controller 6034 (see, e.g., 100A-B).

[0157] As best shown in FIG. 66 , the blowdown reservoir 6014 includes an insert 6620 in this exemplary embodiment. The insert 6620 in this exemplary embodiment is a generally cylindrical sleeve. The insert 6620 is inserted through the top of the closed channel 6610 and is coupled to it. The insert 6620 may have a cross-sectional shape similar to that of the housing 6616, but may be smaller so that the insert 6620 can be nested inside the housing 6616. When assembled, there may be a gap between the inner wall of the housing 6616 and the exterior of the insert 6620. The insert 6620 may also be disposed substantially concentrically with the axis of the housing 6616. In the example shown, the insert 6620 is a tube. The gap may form a second portion 6626 of the inlet path 6614 to the blowdown reservoir 6014. The wall of the insert 6620 may thus shield a portion 6628 of the blowdown reservoir 6014 and function as an obstruction providing a barrier to prevent splashing and other effects of violent liquid movement within the steam chest 6072. The insert 6620 may include an opening 6630 to allow liquid flow from the inlet path 6614 to the shielded portion 6628. In this example, the bottom of the tube-shaped insert 6620 is open, but in other embodiments, the insert 6620 may instead include a window, a mesh section, or a lattice section. A water level sensor 6074, such as any of those described elsewhere herein, may be located in the shielded portion 6628 of the blowdown reservoir 6014. This may allow the water level sensor 6074 to sense the level of blowdown present in the steam chest 6072 substantially free from transient disturbances resulting from violent or active boiling. In some embodiments, the controller 6034 may receive a data signal from the level sensor 6074 in the form of a percentage of the float's displacement along its full displacement range. In some examples, a 1 percent displacement may correspond to a 1-2 ml (e.g., 1.86 ml) volume change in the blowdown reservoir 6014.

[0158] The insert 6620 includes various vent ports 6632 that can displace gas as the liquid level in the blowdown reservoir 6014 changes or as evaporation occurs. The vent ports 6632 may be located near or above the expected liquid level range during certain conditions of operation of the purifier 6010. For example, the vent ports 6632 may be above the expected range of liquid level during production of purified water. These vent ports 6632 may allow gas to displace into or out of the shielded portion 6628 as the float 6627 of the sensor 6074 displaces. Also, a port 6612 may be included in the wall of the closed channel 6610 to allow connection to the evaporator reservoir 6015 via a vent conduit. This may allow gas to displace into or out of the evaporator reservoir 6015 as needed.

[0159] Referring now to FIG. 67, a perspective view of the clarifier 6010 is shown. For clarity, only the blowdown flow conduit 6634 is shown in FIG. 67. As shown, the blowdown reservoir 6014 may be attached to the blowdown flow conduit 6634, which serves as an outlet to the blowdown reservoir 6014. The outlet may establish a flow path from the blowdown reservoir 6014 to the blowdown heat exchanger 6008B. A blowdown reservoir valve 6636 may also be included to control purging of the blowdown process stream from the clarifier 6010. In this exemplary embodiment, the blowdown reservoir valve 6636 is included in the blowdown heat exchanger manifold 6574. The blowdown reservoir valve 6636 may be controlled by the controller 6034 (see, e.g., FIG. 3) to maintain the flow of concentrate from the clarifier 6010. Data from the blowdown level sensor 6074 may be used to direct the operation of the blowdown reservoir valve 6636. The rate of blowdown accumulation can be monitored via blowdown level sensor 6074 so that the level of concentrate in system 6000 can be controlled by varying the duty cycle of blowdown reservoir valve 6636. As the blowdown exits blowdown heat exchanger 6008B, it can flow into a mixing reservoir 6092 that is connected to blowdown heat exchanger manifold 6574. A drain line 6638 can be attached to mixing reservoir 6092 to allow the waste stream to be purged out of system 6000.

[0160] Referring now also to FIG. 68, an exploded view of an exemplary steam chest 6072 is shown. A gasket 6641 may be included to help establish a fluid-tight seal between the steam chest and the tube sheet 6142B that forms the bottom of the steam chest 6072 volume. The steam chest 6072 may include a mist eliminator assembly 6062. In the example shown in FIG. 68, the mist eliminator assembly 6062 includes four levels 6640A-D that redirect the steam flow as it proceeds toward the compressor 6064, similar to that described in connection with FIG. 18. In this exemplary embodiment, an overpressure relief valve 6091 is included at the top of the steam chest 6072, and this valve may open if the pressure in the purifier 6010 rises above a predetermined threshold.

[0161] Referring now primarily to FIGS. 69-72B, after passing through the mist eliminator assembly 6062, the vapor may be compressed by a compressor 6064. The compressor 6064 may be an impeller-type compressor 6064, although other compressor types may be used in alternative embodiments. The compressor 6064 in this exemplary embodiment is mounted off-center relative to the longitudinal axis of the steam chest 6072. The steam chest 6072 includes a receiving recess 6646 for a motor 6644 of the compressor 6064. The receiving recess 6646 may be recessed into a sidewall 6648 of the steam chest 6072. The exemplary receiving recess 6646 protrudes into the interior volume of the steam chest 6072. One or more of the various levels 6640A-D of the mist eliminator assembly 6062 may include a recess receiving cavity 6642 (see, e.g., FIG. 68) that receives the receiving recess 6646.

[0162] The motor 6214 may drive an impeller 6652 mounted within the compressor housing 6650A,B. The compressor housing 6650A,B may be a cast component in some embodiments. The impeller 6652 may be of any design described herein, including a single-stage design (as shown) or a multi-stage design. Steam may enter the compressor housing 6650A,B through an inlet 6654, be compressed by the rotating impeller 6652, and exit the compressor 6064 through an outlet 6656 at an elevated pressure and temperature. The temperature of the steam entering the compressor 6064 from the inlet 6654 may be sensed by an inlet temperature sensor 6066. Similarly, the temperature of the compressed vapor exiting the compressor 6064 through the outlet 6656 may be sensed by an outlet temperature sensor 6068 .

[0163] In some embodiments, the bearings for the motor 6644 may be applied via a coating process (e.g., plasma coating). The coating may be applied to the entire undercut area. The coating may be applied to the end faces. The coating may be, for example, a chromium oxide coating.

[0164] The compressor 6064 may also include a number of mounting points 6658. These mounting points 6658 may house fasteners 6660 that extend through the mounting points 6658. The fasteners 6660 may connect the compressor 6064 to at least one bracket 6662 that extends from another portion of the purifier 6010 and helps support the weight of the compressor 6064. Two brackets 6662 are included in this exemplary embodiment. The fasteners 6660 may also connect the compressor 6064 to a surface 6663 of the steam chest 6072.

[0165] 72B , one or more gaskets 6664 may be compressed between this surface 6663 of the steam chest 6072 and the compressor housing 6650A to establish a fluid-tight seal between the components. The one or more gaskets 6664 may also allow the exterior surface of the steam chest 6074 to provide a portion of the inlet 6654 and / or outlet 6656 of the flow path to the compressor 6064. In the exemplary embodiment shown in FIG. 72B , the bottom of the inlet 6654 and outlet 6656 of the flow path to the compressor 6064 are formed by the upper exterior surface 6663 of the steam chest 6072.

[0166] 73A-73B, a compressor 5000 includes an impeller 5014 driven directly by an electric motor, with the rotor 5016 exposed to pressurized steam and the motor-stator 5025 outside the steam / pressure boundary 5052. The embodiment of compressor 5000 of FIGS. 73A-73B maintains the proper axial clearance between the impeller 5014 and the impeller case halves 5010, 5012 without shimming or other post-assembly adjustments. The clearance between the impeller 5014 and the impeller halves 5010, 5012 is maintained as the compressor heats up from room temperature to approximately 110°C and during operational transients.

[0167] Referring now to FIG. 73B, impeller 5014 presses against rotor 5016 and is held in place by wave spring / circular clip 5013. Rotor 5016 includes bearings 5018 and 5034 at each end. Bearings 5018 and 5034 support radial and axial loads from shaft 5020. In one embodiment, bearings 5018, 5034 are graphite. As explained above, the bearings are hydrodynamic and are supplied with product water through port 5028. Port 5028 is fluidly connected to a flow channel in the center of the shaft that supplies water to bearings 5018 and 5034. In one embodiment, port 5028 is a plastic element that threads into shaft 5020. In other embodiments, the port may be welded, brazed, or machined into shaft 5020. Lubricating water passes through the bearings and into the impeller case, where a portion of the lubricating water evaporates. In some embodiments, the evaporated lubricating water prevents the compressed steam from superheating, improving heat transfer and water production in the purifier. One theory is that because heated steam transfers much less heat than condensing steam, evaporating a portion of the lubricating water to generate a larger mass of saturated steam transfers more heat than a smaller mass of superheated steam.

[0168] 73B, a first end of shaft 5020 is axially and radially secured within impeller case 5010 using bolts 5022 and recesses in impeller case 5010. Shaft 5020 includes bearings 5018, 5034 and bearing support surfaces 5021 and 5036 coated with chromium oxide to extend the life of shaft 5020. The second end of the shaft 5020 is radially constrained by a motor cap 5026. In one embodiment, the motor cap 5026 receives the shaft 5020 in a bore that is a clearance fit on the shaft 5020. In another embodiment, the receiving hole in the motor cap 5026 is a sliding clearance fit on the shaft 5020. In another embodiment, the receiving hole in the motor cap 5026 is a positioning clearance fit on the shaft 5020. In FIG. 73B, the second end of the shaft is lightly constrained axially as the port 5028 threads into the shaft 5020 and engages with the collar 5030. In one embodiment, the motor cap 5026 incorporates the collar 5030 as an integral piece. In another embodiment, the second end of the shaft is not axially constrained by eliminating the collar 5030, providing an axial gap between the collar 5030 and the port 5028, or the port 5028 extending beyond the outer diameter of the shaft 5020.

[0169] Continuing to refer to FIG. 73B , the compressor 5080 maintains good axial clearance between the impeller 5014 and the impeller case halves 5010, 5012 through material selection and design. In one embodiment, the rotor 5016 and impeller case halves 5010, 5012 are made from materials with similar thermal expansion coefficients. In one embodiment, the case halves 5010, 5012 and rotor 5016 are made from austenitic stainless steel, including, but not limited to, SS 316L, SS 316, SS304, and SS304L. The axial position of the impeller 5014 relative to the upper impeller case 5010 is determined by the geometry, stiffness, and thermal expansion of the rotor 5016, upper bearing 5018, and shoulder on the top of the shaft 5020. In one embodiment, the top of the impeller collar 5015 is less than 20 mm from the upper impeller case half 5010. In one embodiment, the distance from the impeller collar 5015 to the upper case 5010 is less than 10 mm. Furthermore, the elements connecting the impeller collar 5015 to the upper case 5010 are rigid and substantially inflexible. In one embodiment, the bearings are graphite and the spindle is stainless steel. The rigidity of the rotor 5020, bearings 5021 and shaft 5020 ensures that there is little relative movement of the impeller 5014 towards either impeller case half 5010, 5012.

[0170] 73B, the rotor 5016 is held in place against the upper case half 5010 by an axial spring 5032 at the opposite end of the rotor 5016. The axial spring 5032 exerts a nominal force of 20-30 lb on a thrust element 5035, which in turn exerts an axial force on the rotor 5016 through a lower bearing 5034. The axial spring 5034 absorbs differential movement between the motor port cap 5026 and the rotor 5016 and maintains the axial position of the impeller 5014 relative to the impeller covers 5010, 5012.

[0171] Referring now to FIG. 74A, the pressure barrier 5052 between the motor stator 5025 and the motor rotor 5015 is a slender, non-metallic cylinder sealed at the top to the compressor structure by seal 5050 and to the thrust element 5056 by seal 5054. In one embodiment, seals 5050, 5056 are O-ring radial seals. The pressure barrier 5052 should have low thermal conductivity to minimize heat loss and low electrical conductivity to minimize eddy current losses between the rotor 5015 and the stator 5025. The pressure barrier 5052 may be made from one of a number of materials including, but not limited to, titanium, polysulfone plastic (PSU), polyphenylsulfone such as Radel, or polyphenylene sulfide plastic (PPS) such as Fortron or Ryton.

[0172] Referring now to FIG. 74B, the permanent magnets of rotor 5015 are protected from the water vapor and moisture of compressor 5080 by a thin, cylindrical rotor shield 5040. Typical rotor magnets are neodymium-iron-boron (NdFeB) magnets, which contain a high amount of iron and are prone to oxidation by water. In one embodiment, the rotor shield may be an autesitic stainless steel, such as SS316L or SS316. The upper edge may be deformed or swaged inward into a groove in rotor 5016. The swaged edge serves to secure the rotor shield onto the rotor. Seals 5044, 5046 prevent water and moisture from entering rotor 5018 and rotor magnets 5015. In one embodiment, seals 5044, 5046 are radial O-ring seals.

[0173] Referring now also to FIGS. 75-77, cross-sectional views of the inlet 6654 and outlet 6656 to the compressor 6064 taken at the designated line in FIG. 75 are shown. The inlet 6654 (FIG. 76) may be formed from flow channels provided in the first and second compressor housing portions 6650A,B, a cover member 6666, and the upper exterior surface 6663 of the vapor chest 6072, as described above. Similar to that described in connection with FIG. 30, the incoming low-pressure vapor flow may be split into multiple flow paths (e.g., bifurcated as shown) by a divider 6674. The cover member 6666 may be attached to the second compressor housing portion 6650B. The cover member 6666 may seal the inlet 6654 from the external environment and may be coupled to the second compressor housing portion 6650B via fasteners or any other suitable fitting. A gasket member 6670 may be included to assist in establishing a suitable seal. The cover member 6666 may be in the shape of a curved sloper, as shown in cross section in FIG. 76. This shape may help gently redirect steam exiting the steam chest 6072 into the compression duct 6672 of the compressor 6064 and may also help limit the amount of turbulence in the flow entering the compressor 6064 from the steam chest 6072. A port 6680 may be included in the cover member 6666 to allow for the introduction of a temperature sensor 6066 into the low pressure steam inlet 6654 flow path.

[0174] The outlet 6656 (FIG. 77) may be formed through flow channels in the first and second compressor housing portions 6650A,B, the second cover member 6676, and the upper exterior surface 6663 of the steam chest 6072, as described above. Similar to that described in connection with FIG. 31, the released high-pressure steam flow may be combined from multiple flow paths into a single flow path as it passes through the divider 6684.

[0175] The second cover member 6676 may be attached to the second compressor housing portion 6650B via fasteners or other suitable fittings. The second cover member 6676 may form a seal between the interior of the outlet 6656 and the external environment. A gasket member 6678 may be included to assist in establishing a suitable seal. The second cover member 6676, like the cover member 6666, may be in the shape of a curved ramp. This shape may help gently redirect steam exiting the compression duct 6672 into the condenser inlet 6686 (see, for example, FIG. 78 ) and may also help limit turbulence. The cover member 6676 may include a port 6682. The port 6682 may allow for installation of an outlet steam temperature sensor 6068.

[0176] Although the compressor 6064 may be mounted off-center relative to the purifier 6010, the compressed, hot vapor may exit the compressor 6064 substantially in-line with the axis of the purifier 6010. After exiting the compressor 6064, the compressed vapor may follow a substantially straight path into the condenser 6076. To facilitate this, the condenser inlet 6686 extending from the compressor outlet 6656 may have a center point that is substantially in-line with the axis of the purifier 6010. Such a straight flow path to the condenser 6076 may help minimize flow losses of the fluid exiting the compressor 6064.

[0177] 78, there is shown an exploded view of the various components of the purifier 6010. As shown, the condenser inlet 6686 may extend through the wall of the steam chest 6072. The condenser inlet 6686 may include a sleeve 6688 protruding from the tube sheet 6142B. The sleeve 6688 may be brazed, welded, integrally formed with, or otherwise coupled to the tube sheet 6142B. One or more gasket members may be included to help create a seal at the interface between the sleeve 6688 and other portions of the condenser inlet 6686. This seal may prevent the flow of condensed blowdown from the vapor chest 6072 from entering the condenser inlet 6686 or the condenser 6076. When assembled, high-pressure compressed steam from the compressor 6064 may proceed along a linear path through the condenser inlet 6686 to the condenser 6076.

[0178] Referring now primarily to FIG. 79 , as the high-pressure, high-temperature steam entering the condenser 6076 begins to condense, a product process stream may begin to accumulate at the bottom of the condenser 6076. Additionally, the latent heat of condensation may be transferred to the evaporator tubes 6140 to assist in the evaporation of new, incoming raw water. A product storage tank 6012 may be included and may be attached to the evaporator-condenser housing 6268. The product storage tank 6012 may be attached to the evaporator-condenser housing 6268 via a product storage tank inlet 6692. The product storage tank inlet 6692 may be disposed adjacent to a product accumulation surface such that the product process stream 6690 may begin to fill the product storage tank 6012 shortly after or simultaneously with the product water beginning to accumulate in the condenser 6076. In this example, the product accumulation surface is the first tube sheet 6142A.

[0179] As shown, a product level sensor 6078 may be included within the product storage tank 6012. The product level sensor 6078 may be any suitable sensor described herein. The product storage tank 6012 is positioned such that the product level sensor 6078 may directly sense the liquid level within the product storage tank 6012 as well as within the condenser 6076. Thus, the condenser 6076 may also serve as a product stream storage tank whose volume may be monitored by the product level sensor 6078. As such, the product storage tank 6012 may be described as an auxiliary product storage tank. In an embodiment, the product level sensor 6078 may measure up to 4 L of product volume in the condenser 6076. In some embodiments, the controller 6034 may receive a data signal from the level sensor 6078 in the form of a percentage of the float's displacement along its full displacement range. In some examples, a 1 percent displacement may correspond to a 40-50 ml (e.g., 43 ml) change in volume in the evaporator and evaporator reservoir.

[0180] The product storage tank 6012 may include a product outlet 6694 (best shown in FIG. 82 ) through which the product process stream may exit the product storage tank 6012. This outlet 6694 may be connected to a product flow conduit leading to the product heat exchanger 6008A, as described elsewhere herein. The exemplary outlet 6694 is adjacent the bottom interior surface 6316 of the product storage tank 6012. The product storage tank 6012 may also include a vent port 6696. The vent port 6696 may allow gas to displace and exit the product storage tank 6012 as the condensed liquid in the condenser 6076 begins to fill the product storage tank 6012. In this exemplary embodiment, the vent port 6696 is connected back to the condenser 6076.

[0181] Referring now to FIG. 80 , a perspective view of the system 6000 is shown. Fluid lines other than the vent flow path 6700 are hidden in FIG. 80 for clarity. As shown, a condenser vent 6698 may be included in the condenser 6076 to allow excess pressure, volatiles, and non-condensable gases to escape from the condenser 6076 as needed. Vent gas from the condenser 6076 may travel along the vent flow path 6700 to a vent valve 6098. The vent valve 6098 may be included on the blowdown heat exchanger manifold 6574. In some embodiments, the duty cycle of the vent valve 6098 may be determined based on the temperature of the low-pressure steam as indicated by data from the compressor inlet temperature sensor 6066 (see, e.g., FIG. 76 ). The current low-pressure steam temperature may be compared to a target low-pressure steam temperature. The target may be at or near 112° C. In some embodiments, the target low-pressure temperature (T LP) is 111°C, and in another embodiment the target T LP The target temperature is 113°C. LP may be as low as 107°C. The difference between these two values ​​may be fed to a proportional (P), proportional-integral (PI), or proportional-integral-derivative (PID) controller, which provides a duty cycle command as an output. This output may be limited to a mode- or state-specific minimum duty cycle and a mode- or state-specific maximum duty cycle (e.g., 100%). Alternatively, the vent valve 6098 may operate at a fixed duty cycle (e.g., less than 15 or 20%). The duty cycle of the vent valve 6098 may be a preset parameter for various states or modes of the system 6000. During water production states, the duty cycle may be set to or have a mode- or state-specific minimum value of 8-12% (e.g., 10%). When in a high temperature production state, the duty cycle may be lower. For example, the duty cycle of the vent valve 6098 may be set to or have a mode or state specific minimum value of 3-7% (e.g., 5%). If the duty cycle of the vent valve 6098 remains at or above a predetermined threshold (e.g., 100%) for more than a certain amount of time (e.g., a number of minutes, e.g., 5 minutes), an error may be generated by the controller 6034.

[0182] To cool the hot gases exhausting from the condenser 6076, the blowdown heat exchanger manifold 6574 may direct the gases after passing through a vent valve 6098 to a mixed reservoir 6092. The mixed reservoir 6092 may be any of those described herein, but in this exemplary embodiment is attached directly to the blowdown heat exchanger manifold 6574. The mixed reservoir 6092 may have a tray-like shape as shown. Alternatively, any other suitable shape may be used.

[0183] Referring now also to FIG. 81 , which shows an exploded view of the assembly of the blowdown heat exchanger manifold 6574 and the mixing storage tank 6092, a vent heat exchanger 6702 may be included. The vent heat exchanger 6702 may be disposed within the interior volume of the mixing storage tank 6092 when fully assembled. In this exemplary embodiment, the vent heat exchanger 6702 is a spiral coil that defines a flow path for gas exhausted from the condenser 6076. In some embodiments, the vent heat exchanger 6702 may include a plate-type heat exchanger. In such an embodiment, a wall (e.g., a bottom wall) of the mixing storage tank 6092 may be at least partially formed from the vent heat exchanger 6702. During operation, the mixing storage tank 6092 may hold a volume of liquid sufficient to at least partially submerge the vent heat exchanger 6702. As the vent gas passes through the vent heat exchanger 6702, it may enter into a heat exchange relationship with the submerged liquid. This may help cool or condense the exhausted process stream before it passes from the vent heat exchanger 6702 into the main interior volume of the mixing storage tank 6092. The vent heat exchanger 6702 may be constructed from a material with high thermal conductivity to facilitate this heat transfer.

[0184] The blowdown manifold 6574 may be attached to the mixing barrel 6092 in any suitable manner. In this exemplary embodiment, the blowdown manifold 6574 is attached to the mixing barrel 6092 via fasteners (not shown). To help establish a fluid-tight seal, a gasket 6703 may be sandwiched between the mixing barrel 6092 and the blowdown manifold 6574 when assembled.

[0185] Referring now to FIG. 82, a perspective view is shown detailing the product flow path 6706 of the exemplary system 6000. For clarity, only the product flow path 6322 is shown in FIG. 82; the flow paths for raw water and other process streams are not shown. As shown, the product water leaving the product storage tank 6012 may flow to both the product heat exchanger 6008A and the bearing feed pump 6080. Separate, dedicated outlets may be included in the product storage tank 6012 for directing the water to the product heat exchanger 6008A, and the bearing feed pump 6080 may be included. The bearing feed pump 6080 may pump a portion of the product water exiting the product reservoir 6012 to the compressor 6064. The bearing feed pump 6080 may be a solenoid pump, a diaphragm pump, or any other suitable pump. As described elsewhere herein, the product water may be used to lubricate the impeller bearings. In this exemplary embodiment, the bearing feed pump 6080 is contained in a bearing feed manifold 6576, which may include a pressure sensor 6081 and a temperature sensor 6083. Data from these sensors may be monitored by the controller 6034 to verify proper function of the bearing feed pump 6080 (see, e.g., FIG. 117 ).

[0186] 82A and 82B, in one embodiment, bearing feed pump assembly 6079 may include a bypass line 6077 connecting the bearing feed pump inlet line from product reservoir 6012 to the bearing feed pump outlet line. Bypass line 6077 may include a check valve 6080A that prevents flow from the pump outlet from returning to the inlet pump. In one embodiment, bypass line 6077 enters bearing feed manifold 6576. Bearing feed manifold 6576 may include a pressure sensor 6083 and a temperature sensor 6081 that measure the pressure and temperature of the bearing lubrication fluid downstream of bearing fluid pump 6080. In one embodiment, where bypass line 6077 is connected to bearing feed manifold 6576, temperature sensor 6081 and pressure sensor 6083 measure the temperature and pressure of the bearing lubrication fluid flowing to compressor 6064.

[0187] The bypass line 6077 and check valve 6080A allow the system to maintain lubrication to the compressor 6064 without operating the bearing feed pump 6080 during some operating conditions. During some operating conditions, the pressure in the product reservoir 6012 is sufficiently higher than the pressure around the compressor shaft 5020 (FIG. 73B) to provide sufficient flow of product water to lubricate the bearings 5018, 5034. At other times, the bearing feed pump is required to provide the lubrication. If the bearing feed pump were operated less frequently during system operation, the overall efficiency of the system would be reduced and the life of the bearing pump could be significantly extended.

[0188] The controller 6034 (see, e.g., FIG. 3) may activate the bearing feed pump 6080 based on logical operating states, compressor speed, pressure measured by sensor 6083, or a combination of these factors. In one embodiment, the controller 6034 may turn off the bearing feed pump 6080 during normal water production state 7460 (FIG. 84B). The controller 6034 may turn on the bearing feed pump 6080 during start of production 7458, hot water production 7472, and transition states 7460, 7430. In another embodiment, the controller 6034 may turn off the bearing feed pump when the measured product pressure exceeds a predetermined value. The product pressure may be measured by one of manifold sensors 6082C or 6082D or determined from the high pressure steam temperature sensor 6068. In one embodiment, the controller 6034 may turn off the bearing feed pump 6080 when the outlet pressure measured by the pressure sensor 6083 exceeds a second predetermined value. In one embodiment, the controller 6034 may turn off the bearing feed pump 6080 for a short period of time and observe the outlet pressure measured by the pressure sensor 6083. The controller 6034 may then de-energize or leave the water feed pump off if the pressure measured by the sensor 6083 remains above a third predetermined value. The controller 6034 may turn off the pump when the compressor rotational speed exceeds a predetermined speed and turn the bearing feed pump back on when the motor speed drops below the second predetermined speed.

[0189] 82, after passing through heat exchanger 6008A, the product water may exit at a reduced temperature after transferring heat to the incoming raw water. The cooled product water may flow from product heat exchanger 6608A through product flow path 6706 to product heat exchanger manifold 6578.

[0190] 83, once in the product heat exchanger manifold 6578, the product water may pass through one or more sensors 6082A-D. In this exemplary embodiment, the sensors 6082A-D are included in a sensor assembly 6708 coupled within the product heat exchanger manifold 6578. The sensors 6082A-D may be a redundant pair of conductivity and temperature sensors. Other sensor types that may provide data signals related to water quality may also be included, such as turbidity, pH, oxidation-reduction potential, TDS, analyte sensors, TOC, etc.

[0191] The product heat exchanger manifold 6340 may also include one or more valves 6344 that may be operated by the controller 6034 (see, e.g., FIG. 3 ) to direct the product process flow based on data provided from at least one sensor 6082A-D. If the water quality (e.g., conductivity value or temperature) is outside a threshold, a diverter valve 6084 leading to the mixing reservoir 6092 may be opened. In this exemplary embodiment, a bypass line 6708 is included connecting the product heat exchanger manifold 6578 to the mixing reservoir 6092 via the blowdown heat exchanger manifold 6574. The diverter valve 6084 may be operated by the controller 6034 to maintain a target level of fluid in the condenser 6076. This level may be preset (possibly for several different modes of operation) or may be varied to meet expected demand as determined by a device at the point of use (e.g., medical system 6004). A PID or PI control loop may be used to set the duty cycle of the diverter valve 6084 based on readings from the product level sensor 6078. If the product level indicated by the data from the product level sensor 6078 exceeds a first percentage (e.g., 40-60% and 50% in some examples), a notification may be generated by the controller 6034. If the product level indicated by the data from the product level sensor 6078 exceeds a second percentage (e.g., 80-95% and 90% in some examples), an error or warning may be generated by the controller 6034.

[0192] If the water quality (e.g., conductivity value or temperature) complies with a predetermined threshold, the controller 6034 (see, e.g., FIG. 3 ) may actuate the point-of-use valve 6086 to direct the product process water vapor to the outlet flow path 6564, which may be a flow path to the medical system 6004 (see, e.g., FIG. 3 ). The valves 6084, 6086 may be actuated by the controller 6034 based on signals the controller 6034 receives from the medical system 6004.

[0193] Referring now to FIGS. 83A and 83B, the product heat exchanger manifold 6578 may be configured to fit within bulkhead fittings and includes internal flow paths that improve priming performance. Bulkhead fittings 5946-5949 are mounted to the rear wall of the high temperature compartment housing 6102 ( FIG. 50 ) and provide fluid conduits for raw water 5947, 5949 entering the high temperature compartment and product water 5946, 5948 exiting the high temperature compartment. Bulkhead fittings 5946-5949 are configured to receive nipples 5938, 5942 of the product heat exchanger manifold 6578. In one embodiment, the nipples include an elastomeric element 5940 that seals against the interior surface of the receiving bulkhead fitting. In one embodiment, the elastomeric element 5940 is an O-ring and forms a radial seal between the small diameter section 5942 of the nipple and the large diameter section 5948A of the bulkhead fitting 5948. The smaller diameter section 5942 of the nipple fits into a matching smaller diameter section 5948 B of the bulkhead fitting 5948 .

[0194] The product heat exchanger manifold 6578 is attached to the rear wall of the hot compartment housing by screws or studs that pass through the manifold in flange 5944. The manifold can be removed from the water purification device without having to reach into the hot compartment by loosening the nuts on the studs or screws and then pulling the product heat exchanger manifold off the rear wall.

[0195] Referring now to FIG. 83B , product water flows through two conductivity recesses 5950A, 5950B and past two conductivity sensors 5932A, 5932B. Conductivity measurements are degraded if air bubbles are trapped in the conductivity recess flow. Accuracy of the conductivity measurement depends on removing air from the conductivity recesses 5950A, 5950B during priming. In one embodiment, the priming flow first passes through conductivity sensor 5932A and then through passageway 5954 before entering the bottom of conductivity recess 5950B. Fluid passageway 5954 connects the top of the first recess 5950A to the bottom of the second recess 5950B, which helps flush air bubbles through both recesses during priming and avoids trapping air bubbles at the top of the conductivity recesses 5950A, 5950B.

[0196] 83C-83F, conductivity sensor 5932 includes two metal probes 5960, a temperature sensor 5976, a circuit board 5968, a housing 5970, and a cover 5972. In one embodiment, the housing is overmolded onto the stainless steel probe 5960. The circuit board 5968 is attached to the probe 5960 in a manner that minimizes rust and contamination on the electrical connections. Conductivity sensor 5932 is assembled by mechanically attaching the circuit board 5968 to the housing 5970. Each washer 5966 is welded, soldered, or mechanically attached to a wire 5964. In a preferred embodiment, wire 5964 is soldered to washer 5966. The washer 5966 / wire 5964 assembly is placed over each metal probe 5960, with a central section 5967 protruding through the center of washer 5966. The washer 5966 is secured to the metal probe 5960 by swaging, deforming, or mushrooming the top of the central section 5967 to capture the washer, as shown in FIG. 83F. The wire 5964 is soldered to a pad 5962 on the circuit board 5968. The temperature sensor 5976 is inserted into one side of the metal probe 5960 and potted in place. The leads from the temperature sensor are soldered to the circuit board 5968. During assembly, especially during the swaging operation, the conductivity probe 5960 should not come into contact with ferrous materials or tools. Ferrous tools can impart iron particles to the stainless steel probe, which can then lead to rust and degradation of the conductivity signal.

[0197] Control Algorithm Any of the systems 6000 described herein may operate in several different modes. These modes may regulate the operation of the device at a high level. In each of these modes, the controller 6034 may control the system 6000 differently depending on what the mode is designed to achieve. For example, some modes may be used by the controller 6034 to establish or maintain prerequisite conditions for that mode before the controller 6034 transitions to the next mode. Other modes may keep the system 6000 in a ready state (e.g., filled and at a certain temperature) from which purified water can be produced with relatively little delay. At a low level, the controller 6034 may, for example, operate the system 6000 in at least one state per mode and transition the system 6000 through several states within each mode. During typical use of the system 6000, the controller 6034 may transition between several modes. However, certain transitions between certain modes may be prohibited. Some example modes and example allowed transitions are shown in Table 1 below.

[0198] [Table 1]

[0199] Depending on the embodiment, the medical system 6004, which serves as the point-of-use for the system 6000, may generally control the mode switching. Non-medical systems, or any other point-of-use devices, such as systems for producing water for drinking or other household consumption, may have similar controls. The medical system 6004 may make the determination as to which mode of system 6000 operation may be required and instruct the controller 6034 to govern the switching when required by the medical system 6004. The medical system 6004 may query the controller 6034 for information from the system 6000 to make the mode switching decision. The controller 6034 may also or alternatively provide information to the medical system 6004 on a predetermined basis. The controller 6034 of the system 6000 may transition the system 6000 into fail-safe mode without instruction from the medical system 6004 (although the medical system 6004 may similarly instruct the system 6000 to enter fail-safe mode). The controller 6034 of the system 6000 may switch states within a mode depending on certain operating characteristics or parameters. The decision to switch states may be made by the controller 6034 without direct instructions from the medical system 6004.

[0200] Some modes, such as an override mode (if included in the embodiment), may be available only via a technician or similar maintenance personnel. This mode may allow manual control of various valves, control set points or targets, and other parameters via a technician interface. The technician interface may be, for example, a laptop, PC, tablet, smartphone, or point-of-use device user interface. The technician may require one or more of specific hardware, a password, an encoded key, etc. to access the override mode.

[0201] Referring now to FIGS. 84A-84B, a flow diagram 7430 is shown illustrating various operating states during typical use of one embodiment of the system 6000. As shown, an idle state may be entered at block 7432. In the idle state, the controller 6034 may close all valves, disable any control loops, water level controllers, stop motors, etc. Each valve may be commanded to close individually. The idle state may be used in idle mode, which may be the starting mode for the system 6000 upon power-up. The system 6000 may be capable of transitioning to idle mode from any other mode other than fail-safe mode. In some embodiments, the idle state may be utilized when the system 6000 is in either idle mode or fail-safe mode. However, the idle state may not be exitable in fail-safe mode. A service call may be required before use of the device is permitted again.

[0202] In some embodiments, when the system is powered on and receives a communication regarding the system 6000 that it is in idle mode, the point-of-use device may command a transition to standby mode. Standby mode may bring the system 6000 to a point where the system 6000 is ready to quickly produce purified water. This may include filling the purifier 6010 of the system 6000 and heating the fluid contained in the purifier 6010. Once the purifier 6010 is properly filled and heated, standby mode may maintain the system 6000 at this fill level and temperature.

[0203] Upon receiving a command to enter standby mode, the controller 6034 may transition the system 6000 to a standby state. The standby state of standby mode may be used to maintain the fill level and temperature of the purifier 6010. The standby state is described in more detail in connection with FIG. 98. The standby state may be terminated if either the fill level or the temperature are outside their respective limits.

[0204] In an alternative embodiment, and as shown, in some embodiments, the controller 6034 may transition from the idle state to the integrity check state at block 7434. In various embodiments, the integrity check state may check various components of the system 6000 to ensure they are operating as expected. The integrity check state is described in more detail in connection with FIG. 85.

[0205] In example flow chart 7340, the controller 6034 transitions the system 6000 to a Fill state at block 7436. The purifier 6010 may be filled in the Fill state. The Fill state is described in more detail with respect to FIGURES 86 and 87. The controller 6034 may then transition the system 6000 to a Heat state at block 7438. The Heat state may heat the fluid in the purifier 6010 to a temperature setpoint. The Heat state is described in more detail with respect to FIGURE 88. Once the temperature reaches the setpoint, a transition may be made back to the Wait state at block 7440.

[0206] After the medical system 6004 (or other point-of-use device) receives a communication indicating that the system 6000 is being maintained at a certain fill level and temperature in the standby state, the medical system 6004 may instruct the system 6000 to transition to a flush mode. A flush state may be used in this mode. In this example, the flush state is entered at block 7442. In the flush state, raw water may enter the system 6000 and flow through any filters 6006A, B in the system 6000. This may be done before a water sample is taken to ensure adequate filter integrity. This may also serve to ensure that any water taken in a subsequent water sample is more representative of the filtering capabilities of the filters 6006A, B. The flush mode is described in more detail in connection with FIG. 89. Certain characteristics of interest related to the filters 6006A, B may be monitored during the flush state. If the characteristics of interest are deemed acceptable at block 7444, then a sampling state may be entered at block 7446. If the characteristics of interest are not acceptable at block 7444, a filter change preparation state may be entered at block 7448.

[0207] Depending on the embodiment, data collected during this monitoring may be communicated to the medical system 6004 (or other point-of-use device), and the medical system 6004 may make a determination of acceptability. In other embodiments, the controller 6034 of the system 6000 may make a pass / fail determination based on the data collected during this monitoring. The pass / fail determination may be communicated to the medical system 6004. If the filter is deemed acceptable, the medical system 6004 may command a mode transition to a sampling mode, which may cause the sampling state to be entered at block 7446. If the filter is not acceptable, the medical system 6004 may command a mode transition to a prepare-to-change mode, which may cause the filter-to-change-ready state to be entered at block 7448.

[0208] In the Ready to Replace mode, the filters 6006A,B and the lines leading to and leaving the filters 6006A,B may be depressurized so that the filters 6006A,B may be removed with minimal splashing of water. This may be done in the Ready to Replace Filter state, which is described in more detail in connection with FIG. 91. A new filter may be installed and the Replace Filter Flush state may be entered at block 7450. This state is further described in connection with FIG. 91. Properties of interest related to the filters 6006A,B may be monitored in the Replace Flush state and compliance with acceptability criteria may be required before entering the Sampling state.

[0209] In the sampling state, the controller 6034 may operate the sampling port 6038 to dispense a sample of filtered water for testing. If the test is acceptable at block 7452, a wait state may be entered at block 7454. If the test is unacceptable at block 7452, a replace filter ready state may be entered at block 7448. In one example, the test may be performed manually (e.g., using one or more test strips) and the results may be entered directly into a user interface of the medical system 6004. The transition to the replace filter ready state or the wait state may be in response to a command from the medical system 6004 to enter either the replace ready mode or the wait mode. The command may be generated based on whether the test was acceptable or unacceptable.

[0210] When the medical system 6004 is ready (e.g., startup checks are completed, required user interaction has been received), the medical system 6004 may command the system 6000 to enter a normal water production mode. In the normal water production mode, the controller 6034 may place the system 6000 in several states. Initially, the controller 6034 may enter a production ready state at block 7456. In this state, the controller 6034 may prepare to start the compressor 6064. This may include running the bearing feed pump 6080 for a period of time. The production ready state is further described in connection with FIG. 92. The controller 6034 then enters a production start state at block 7458, during which the compressor 6064 is ramped up to operating speed. The production start state is further described in connection with FIG. 93. The controller 6034 may then enter a production run state at block 7460. This state is further described in connection with FIG. 94.

[0211] Certain characteristics of interest related to the purified water produced by the system 6000 may be monitored in the production run state. If it is determined at block 7462 that diversion of product water from the point of use is necessary, the controller 6034 may transition the system 6000 to a wait state at block 7464 or to a production bypass state at block 7466. The transition to the wait state at block 7464 may occur if the conductivity of the product water rises above a predetermined threshold (e.g., 10 μS). The transition to the production bypass state at block 7466 may occur if the temperature of the product water rises above a predetermined threshold. In the bypass state, the product water may be sent to the drain 6018 of the system 6000 and may be prevented from proceeding to point-of-use devices. The bypass state is further described in connection with FIG. 94. If, at block 7468, the bypass is no longer needed (e.g., if the temperature is back within limits), the controller 6034 may return the system 6000 to the production run state at block 7460.

[0212] The controller 6034 may remain in the normal water production state until it receives a command from the medical system 6004 (or other point-of-use device) to change modes. The medical system 6004 may command the mode change after completing a treatment, for example. If the components of the medical system 6004 are reusable, the medical system 6004 may command a mode change to a hot water production mode. This mode may provide hot water to the medical system 6004, which the medical system 6004 may use to disinfect itself. Upon receiving a command to enter the hot water production mode, the controller 6034 of the system 6000 may enter a high temperature transition state at block 7470. In this state, the controller 6034 may change the motor speed toward its high temperature operating speed and may transition between the normal production control loop and the hot water production control loop. This state is further described in connection with FIG. 95. The controller 6034 may transition the system 6000 to the high temperature production state at block 7472. In this state, high temperature purified water may be produced and provided to a medical system (or other point-of-use device). The high temperature production state is further described in connection with FIG. 96. If the conductivity of the product water rises above a threshold at block 7474, the controller 6034 may transition the system 6000 to a standby state at block 7464. In some embodiments, if the temperature falls below the threshold, a bypass state may be entered; however, if the medical system 6004 includes a heater, such entry into the bypass state may not be necessary.

[0213] The hot water production state may be used in a self-sanitizing mode for the system 6000. This mode may be entered automatically by the system 6000 after the medical system 6004 indicates that the hot water mode is not needed. Alternatively, the medical system 6004 may command the system 6000 to enter the self-sanitizing mode. In this mode, the hot water production state may be used to flow hot water through various lines of the system 6000. This mode is further described in connection with FIG. 97.

[0214] When hot water production is no longer needed, the system 6000 may be commanded to enter a standby mode. The controller 6034 may keep the system 6000 in a state ready to quickly produce purified water the next time it is needed. This may also help increase the efficiency of the system 6000, as a significant amount of energy may be required to bring the system 6000 from a cold start up to operating temperature.

[0215] Referring now to FIG. 85, a flowchart 7500 illustrating some example operations that may be performed in the Integrity Check State is shown. The Integrity Check State may be entered at block 7502. In the Integrity Check State, the controller 6034 may issue a command to each valve included in the system 6000 to transition to a closed state at block 7504. At block 7506, the controller 6034 may command the motor speed to zero, the bearing feed pump to an off state, and the heater duty cycle to zero. At block 7508, if one or more valves do not close as commanded and / or the motor, bearing feed pump, and heater do not turn off as commanded, an error may be generated at block 7510. If at block 7508 all valves close as commanded and the motor, bearing feed pump, and heater are all off as commanded, the controller 6034 may command a test of various electrical relays of the system 6000 at block 7512. The relays being tested may be those on the AC high voltage bus of system 6000. The relays may be commanded to a particular state, and voltage readings may be taken from the bus to verify that the relays have changed state as commanded. If the relay test does not pass at block 7514, an error may be generated at block 7510. If the relay test passes at block 7514, the controller 6034 may transition system 6000 to the next state at block 7516. This state may be, for example, a fill state in one particular embodiment.

[0216] It should be noted that the integrity check state may be entered each time the system 6000 is powered up, but may also be entered before starting to provide water to a point-of-use device, for example, each time a point-of-use device (e.g., medical system 6004) commands the system 6000 to exit the standby state. If the point-of-use device is a medical system 6004, such as a dialysis system, the system 6000 may go through the integrity check state before providing water for each individual therapy performed by the medical system 6004.

[0217] In the context of a dialysis system, therapy may typically be administered relatively consistently. The system 6000 may operate in standby mode for some amount of time while the patient, for example, is at work or going about their day during waking hours. By remaining in standby, the system 6000 may be quickly ready to produce water for use in therapy when needed. Because therapy typically begins when the patient prepares for bed, the controller 6034 may instruct the system 6000 to enter the integrity check state based on a preprogrammed schedule that ensures the integrity of the system 6000 is verified immediately before therapy is likely or scheduled to begin. Alternatively or additionally, the integrity check state may be entered after the self-disinfection state is completed in some embodiments.

[0218] Referring now to FIG. 86, a flowchart 7230 illustrating some exemplary operations that may be performed in the Fill state is shown. The Fill state may be entered at block 7232. In the Fill state, a source valve controller, such as those described in connection with FIG. 100 or 101A-101C, may be enabled. Other controllers, such as a heater controller, compressor motor controller, and bearing feed pump controller, may be disabled. At block 7236, the product reservoir outlet valve may be closed and the vent valve 6098 (see, e.g., FIG. 3) may be opened. The source valve controller may also fill the clarifier 6010 at block 7236 (e.g., as described in connection with FIG. 87).

[0219] At block 7238, the controller 6034 may receive a data signal from the product reservoir level sensor 6078 (see, e.g., FIG. 3) indicating the liquid level in the product reservoir 6012 (see, e.g., FIG. 3). If the product level is less than a minimum value at block 7240, the controller 6034 may transition the system 6000 to a first state (e.g., a standby state) at block 7242. The minimum level may be between 5 and 15% (e.g., 10%) of the water level and may ensure that the bearing feed pump 6080 (see, e.g., FIG. 3) has an adequate supply of fluid to lubricate the bearings of the compressor 6064 (see, e.g., FIG. 3). If the product level is greater than the minimum at block 7240, the controller 6034 may transition the system 6000 to a second state (block 7245) if the evaporator 6060 (see, e.g., FIG. 3 ) level is at or above a threshold (e.g., 50% or 55%) at block 7244. The second state may be a heating state. If the evaporator 6060 is not above the threshold at block 7244 and the purifier 6010 is filling too slowly at block 7246, an error may be generated at block 7248. For example, an error may be generated if a 5-10 minute (e.g., 5 minute) timer has elapsed.

[0220] 87, an exemplary flow chart 7130 is shown detailing several operations that may be performed to fill the evaporator 6060 (see, e.g., FIG. 3) of the purifier 6010 (see, e.g., FIG. 3). This may occur, for example, during a fill state in a production mode or standby mode of operation of the system 6000. The controller 6034 (see, e.g., FIG. 3) of the system 6000 may control the source proportioning valves 6050A,B (see, e.g., FIG. 3) during the fill state such that the evaporator 6060 fills quickly while mitigating the possibility of overshoot.

[0221] As shown, the controller 6034 may determine the difference between the current fill level of the evaporator 6060 and the target level at block 7132. The current level may be sensed via an evaporator level sensor 6073 (see, e.g., FIG. 3 ) in data communication with the controller 6034. The target level may be a predetermined value. If the compressor motor of the purifier 6010 is running at block 7134, the controller 6034 may command the source proportioning valves 6050A,B to be closed at block 7136. The controller 6034 may wait for the motor to stop or slow to a relatively low speed before filling the evaporator 6060. If the current level is above the target level at block 7138, the source proportioning valves 6050A,B may be closed at block 7140. The evaporator may be drained at block 7138 and a new difference between the target and current value may be determined at block 7132.

[0222] If the motor is off at block 7134 and the evaporator water level is below the target at block 7138, the controller 6034 may fill the evaporator 6060. If the difference determined at block 7132 is not within a predetermined range of the target at block 7142, the duty cycle of the source proportioning valves 6050A, B may be set to 100% at block 7144. This may allow the evaporator 6060 to fill as quickly as possible. If the difference from block 7132 is within a predetermined target range at block 7146, the duty cycle of the source valves may be set to a slow fill duty cycle value at block 7146. In some embodiments, the range at block 7142 may encompass values ​​within 25% of the target water level or 20% of the target water level. The slow fill duty cycle may be around 20-35% (e.g., 25%). This may help prevent overshooting the target water level. Once the target water level is reached at block 7148, the fill may be complete at block 7150.

[0223] Referring now primarily to the exemplary flowchart 7260 of FIG. 88 , the controller 6034 (see, e.g., FIG. 3 ) may prepare the purifier 6010 (see, e.g., FIG. 3 ) for water purification by raising the fluid in the purifier 6010 to a temperature or temperature range. In some embodiments, multiple temperature targets may be used. For example, a target low-pressure steam temperature and a target sump temperature may be used. For example, the controller 6034 may heat the fluid in the evaporator 6060 (see, e.g., FIG. 3 ) to a point where the purifier 6010 can transition to a purified water producing state.

[0224] As shown, a heating state may be entered at block 7262. In the heating state, the controller 6034 may close the outlet to the purifier 6010 and close the inlet to the purifier 6010 at block 7264. The compressor 6064 (see, e.g., FIG. 3) and bearing feed pump 6080 (see, e.g., FIG. 3) may likewise be disabled at block 7264. The fluid in the purifier 6010 may then be heated to a temperature target by the heating element 6054 (see, e.g., FIG. 3) at block 7266. The controller 6034 may vent the purifier 6010 by operating the vent valve 6098 (see, e.g., FIG. 3). The vent valve 6098 may be operated to achieve or maintain a steam temperature setpoint. The controller 6034 may regulate the operation of the vent valve 6098 as described elsewhere herein (see, e.g., the description of FIG. 80).

[0225] The controller 6034 may receive a product level measurement from the product level sensor 6078 at block 7268. If the product level is below a minimum value at block 7270, the controller 6034 may transition the system 6000 to a standby state at block 7272. The minimum value may be 7-15% (e.g., 10%) in some embodiments. Otherwise, the controller 6034 may receive a sump temperature value and a low-pressure steam temperature value at block 7274. These may be received via data signals from the sump temperature sensor 6059 (e.g., see FIG. 3 ) and the low-pressure steam temperature sensor 6066 (e.g., see FIG. 3 ), respectively. If one or both of these values ​​are not above their respective targets at blocks 7276 and 7278, the controller 6034 may return to block 7264 and continue heating and venting. If the sump temperature and low pressure steam temperature are above their respective minimum values, the controller 6034 may transition the system 6000 to the next state. This state may be, for example, a standby state.

[0226] Referring now primarily to the exemplary flowchart 7160 of FIG. 89 , a flush state may be used in a flush mode. Upon entering the flush state at block 7162, the cooling valve 6100 (see, e.g., FIG. 3 ) may be opened and the source proportioning valves 6050A, B (see, e.g., FIG. 3 ) to the heat exchangers 6008A, B (see, e.g., FIG. 3 ) may be closed at block 7164. The cooling valve 6100 may be operated at a 100% duty cycle during the flush. At block 7166, the controller 6034 (see, e.g., FIG. 3 ) may receive filtration data from various sensors monitoring the filters 6006A, B. For example, data may be received from the pre-filtration and post-filtration pressure transducers 6036, 6044. If the post-filtration pressure falls below a minimum pressure (e.g., 10 psi or greater) at block 7168, the controller 6034 may continue monitoring the filtration data at block 7166 unless a timeout period has elapsed at block 7170. If the timeout period has elapsed, the controller 6034 may generate a timeout error at block 7172. The timeout period may be 7 to 15 minutes (e.g., 10 minutes). In some embodiments, if a timeout error is generated at block 7172, the filters 6006A, B may need to be replaced.

[0227] If the post-filtration pressure is above the minimum pressure at block 7168, the controller 6034 may determine the pressure drop between the reading of the pre-filtration pressure sensor 6036 and the reading of the post-filtration pressure sensor 6044 at block 7174. If the pressure drop is below a predetermined limit at block 7176, the controller 6034 may continue monitoring the filtration data at block 7166 unless a timeout period has elapsed at block 7170. If the timeout period has elapsed, a timeout error may be generated at block 7172. If the pressure drop is greater than the predetermined limit at block 7176, the flush timer may be incremented at block 7178. The predetermined limit on pressure drop may be at least 1 psi.

[0228] If the flush timer has not incremented above its minimum limit (e.g., 5 minutes) at block 7180, the controller 6034 may continue monitoring the filtration data at block 7166 unless a timeout period has elapsed at block 7170. If the timeout period has elapsed, a timeout error may be generated at block 7172. Although not shown, the flush timer may be reset to zero if the post-filtration pressure value or the pressure drop between the pre-filtration and post-filtration sensors 6036, 6044 falls below their respective minimum values. If the flush timer has incremented above the minimum value at block 7180, the controller 6034 may transition the system 6000 to the next mode or state at block 7182. Alternatively, the controller 6034 may notify a point-of-use device (e.g., medical system 6004 of FIG. 3 ), which may instruct the controller 6034 to transition the system 6000 to another mode or state. The next mode may be sampling mode.

[0229] The sampling state may be used in the sampling mode. In the sampling state, and then referring to the exemplary flowchart 7190 shown in FIG. 90, the controller 6034 may dispense a sample for manual testing, which may again be used to determine the suitability of the filters 6006A, B. In other embodiments, a digital testing instrument may be used, and testing may not be manual. As shown, the sampling state may be entered at block 7192. The duty cycle of the cooling valve 6100 (see, e.g., FIG. 3) may be set to the sampling duty cycle (e.g., 50%) at block 7194. If provided, the illuminator for the sampling port 6038 (see, e.g., FIG. 3) may also be powered on at block 7194. If a sampling button press is not detected at block 7196, the sampling valve may remain closed at block 7198. If the sampling button is pressed at block 7196, the sampling valve may be opened at block 7200. In some embodiments, the sampling valve may be commanded to close by the controller 6034 if the sampling button remains depressed for more than a predetermined time. For example, the controller 6034 may close the sampling valve after 5 seconds.

[0230] Referring now primarily to the exemplary flowchart 7210 of FIG. 91 , if filters 6006A, B (see, e.g., FIG. 3 ) are to be replaced, the controller 6034 (see, e.g., FIG. 3 ) may transition the system 6000 to a filter replacement ready state. The filters 6006A, B may need to be replaced if a water sample from the filtration mechanism fails a quality test (e.g., a chlorine or chloramine test). The filters 6006A, B may also need to be replaced if the pressure drop across the filters 6006A, B is outside a predetermined range or if the post-filtration pressure measured downstream of the filters 6006A, B is too low. In some embodiments, the filters 6006A, B may require replacement based on usage characteristics, such as volume filtered, time filtering raw water, time since installation, etc. In one embodiment, the controller 6034 may be instructed by an attached point-of-use device (e.g., medical system 6004 of FIG. 3) to enter replacement mode if a quality test fails or if other characteristics of interest related to the filters 6006A, B indicate that replacement may be necessary.

[0231] When in replacement mode, the controller 6034 may go through a replacement readiness state and a replacement flush state. As shown in FIG. 91 , a filter replacement readiness state may be entered at block 7212. All valves except the cooling valve 6100 (see, e.g., FIG. 3 ) may be closed at block 7214. This may allow any water pressure that may be present in the system 6000 to be vented to the drain 6018 (see, e.g., FIG. 3 ) of the system 6000. The controller 6034 may monitor post-filtration pressure data at block 7216. If the post-filtration pressure falls below a threshold at block 7218, the controller 6034 may wait a predetermined amount of time (e.g., 10 seconds) at block 7220. If the pressure rises above the threshold during this waiting period, the waiting period may be reset to zero if the pressure falls below the threshold again. The cooling valve may be closed at block 7222. The controller 6034 may transition the system 6000 to idle at block 7222. The user may then remove the used filters from the system 6000 and install a new set of filters before the next use.

[0232] Once the new filters 6006A, B are installed, the controller 6034 may transition the system 6000 to the Flush New Filter state. In some examples, the completion of installation of the new filters 6006A, B may be indicated via the user interface of the point-of-use device. The controller 6034 may transition the system 6000 to the Flush New Filter state upon receiving communication from the point-of-use device that the user has indicated that the new filters have been installed. The Flush New Filter state may be similar to the Flush state described in connection with FIG. 89 . The timeout period may be longer for the Flush New Filter state. In some embodiments, the timeout period may be 20 minutes or double the normal flush timeout period. Additionally, the filters 6006A, B may be flushed for a longer period of time during a new filter flush. In some embodiments, the minimum limit used in block 7178 for a new filter flush may be 15 minutes or three times the minimum limit used in a normal flush. After rinsing, the controller 6034 or point-of-use device may request that the system 6000 collect another water sample to ensure that the new filters 6006A,B are adequate.

[0233] Once the filters 6006A,B are deemed adequate, the controller 6034 (e.g., see FIG. 3 ) may begin preparing the purifier 6010 (e.g., see FIG. 3 ) for water purification. In some embodiments, once the filters 6006A,B pass certain tests, the point-of-use device (e.g., medical system 6004 of FIG. 3 ) may instruct the controller 6034 to transition the system 6000 to a normal purified water production mode. The normal purified water production mode may produce product water at a temperature around 30-40°C (e.g., 37°C). In other embodiments, the normal purified water production temperature may be lower. For example, if the point-of-use device (e.g., medical system 6004 of FIG. 3 ) includes a heater, the target temperature may be lower than the temperature at which the point-of-use device uses the water. In some embodiments, the target temperature may be 20-30°C (e.g., 25°C). The controller 6034 may alternatively prepare the system 6000 for purified water production by transitioning the system 6000 into a standby mode. This may help minimize the amount of time required to begin producing purified water 6010 when a point-of-use device or system commands a mode change to normal purified water production mode. This preparation may include, for example, maintaining the temperature and fill level of the purifier 6010 at a point where the purifier 6010 can be transitioned to a purified water production state.

[0234] Referring now primarily to the exemplary flowchart 7290 of FIG. 92 , the controller 6034 (see, e.g., FIG. 3 ) may prepare the clarifier 6010 (see, e.g., FIG. 3 ) for water purification by starting the bearing feed pump and controlling the blowdown level to a starting fill percentage. As shown, at block 7292, the controller 6034 may transition the system 6000 to a production-ready state. The bearing feed pump may be commanded to operate by the controller 6034 at block 7294. The blowdown level may also be controlled to a starting level at block 7294. In the production-ready state, the motor may remain off and the product outlet valve may remain closed. Venting the clarifier 6010 may continue as needed to maintain a target steam temperature in the clarifier 6010. At block 7296, a timer may be incremented. This timer may be required to accumulate more than a predetermined amount of time sufficient to lubricate the bearings of the motor of the compressor 6064 (see, e.g., FIG. 3 ). This may be, for example, 15 seconds to 1 minute (e.g., 30 seconds). If, at block 7298, the blowdown level is at or below a predetermined level (e.g., 35%) and the timer has accumulated more than a predetermined threshold at block 7300, the controller 6034 may transition the system 6000 to the next state. In some embodiments, the controller 6034 may generate an error (not shown) if the timer accumulates more than a certain value (e.g., 5 minutes). The next state may be a Start Production state.

[0235] In the Production Startup state, and then referring primarily to flowchart 7480 of FIG. 93 , the compressor 6064 (see, e.g., FIG. 3 ) may be ramped up to a speed, and set points for various control loops of the system 6000 may be set. Any product water produced may be diverted to drain 6018 (see, e.g., FIG. 3 ) and may not be in fluid communication with point-of-use devices or systems in this state. Additionally, the Production Startup state may monitor various operating characteristics of interest for compliance with predetermined criteria. The controller 6034 may not allow a transition to the Production Run state until the operating characteristics of interest comply with the predetermined criteria.

[0236] As shown, a production start state may be entered at block 7482. Control set points for various control loops of the system 6000 may be set at block 7484. The control loops may be executed at block 7486. The compressor motor may be ramped towards its operating speed at block 7488. If a production transition condition is not met at block 7490, the controller 6034 may return to block 7486. Otherwise, the controller 6034 may check whether a minimum time for which the transition condition is met has elapsed at block 7492. If this time has elapsed, the controller 6034 may transition the system to a production run state at block 7494. Otherwise, the controller 6034 may return to block 7486.

[0237] The production transition conditions may include criteria related to the temperature and / or conductivity of the product water exiting the product heat exchanger 6008A (e.g., as read by sensors 6082A-D in FIG. 3). For example, the temperature may be required to be less than a few degrees (e.g., 2°C) above the temperature setpoint for the production run state. The conditions may also include criteria related to the temperature difference between the raw water entering the system and the purified product water entering and / or exiting the product heat exchanger 6008A. The above conditions may also include criteria related to the speed of the compressor 6064. For example, the compressor speed may be required to be greater than the minimum production run speed. The conditions may also include criteria related to the blowdown level or rate and the product level. Additionally, there may be a timer for the time that all criteria must be met for the controller 6034 to consider the production condition to be met. Individual timers for each criterion or subset of criteria may be used.

[0238] In some examples, the start-up state may be entered before entering the hot water production state. Similar criteria may be imposed before a transition to the hot water production state is permitted, although the values ​​corresponding to each particular criterion may be different when the system 6000 attempts to transition to the hot water production state.

[0239] 94, after preparation (e.g., in the production preparation state and the production start state) is complete, the controller 6034 (see, e.g., FIG. 3) may transition the system 6000 to a purified water production state or a production run state. As shown, the production run state may be entered at block 7312. At block 7314, the controller 6034 may execute various control loops of the system 6000. For example, a diversion controller may be implemented at block 7314. The diversion controller may divert water produced by system 6000 as described elsewhere herein (see, e.g., Figures 83 and 122). Controller 6034 may also implement an aeration controller at block 7314. The aeration controller may exhaust steam from clarifier 6010 as described elsewhere herein (see, e.g., Figure 80). Controller 6034 may also implement a heater controller at block 7314. The heater may be controlled as described elsewhere herein (see, e.g., Figures 119-121). Controller 6034 may further implement a motor controller at block 7314. The motor may be controlled as described elsewhere herein (see, e.g., Figures 109-118). Controller 6034 may also implement a blowdown controller and an influent raw water split controller at block 7314. This may be accomplished as described elsewhere herein (see, for example, FIGS. 100-101C). Also, at block 7316, a timer may be incremented.

[0240] If the product temperature leaving product heat exchanger 6008A (see, e.g., FIG. 3) rises above a threshold value at block 7318, controller 6034 may transition system 6000 to a product water bypass state at block 7320. This threshold may be around body temperature (e.g., 37°C) in one example. Similarly, if a product water conductivity threshold is violated (not shown), the product bypass state may be entered at block 7320. In some embodiments, violation of the conductivity threshold may cause a transition to a wait state. Temperature and conductivity may be sensed by sensors 6082A-D (see, e.g., FIG. 3). The product water bypass state may be entered at block 7320 if the product water level drops below a threshold value at block 7322. This value may be, for example, 20% and may be measured by product water level sensor 6078 (see, e.g., FIG. 3). Once the sensor readings and product level comply with their respective thresholds at block 7324, a bypass timer may be incremented at block 7326. This bypass timer may be required to increment beyond a predetermined value before the bypass state is terminated and product water may be produced for dispensing to points of use in communication with the system 6000. If the bypass timer has not yet incremented beyond the predetermined amount at block 7328, the controller may return to block 7324. Once the bypass timer has incremented beyond the predetermined amount, the controller 6034 may transition the system 6000 back to the water producing state at block 7312.

[0241] While in the water production state, if a hot water mode request is received by the controller 6034 (e.g., from a point-of-use device) at block 7330, the controller 6034 may transition the system 6000 to a hot water production ready state at block 7332. If the product temperature and product water level comply with their respective thresholds at blocks 7318, 7322 and a hot water request is not received at block 7330, purified water may continue to be produced. In other embodiments, transitions to the hot water production ready state may be automatic. These transitions may be based on the time accumulation of a timer incremented at block 7316. If the timer accumulates more than the expected usage time at block 7334, the hot water production ready state may be entered at block 7332. If the system 6000 is providing purified water to a medical system 6004 (see, e.g., FIG. 3 ), the expected usage time may be a therapy time. The therapy time may be communicated from the medical system 6004 to the controller 6034 of the system 6000 and may be updated if changes are made. If the timer increments above the therapy time, for example, the controller 6034 may transition the system 6000 to the hot water production ready state 7332. If the timer has not incremented above the threshold at block 7334, the controller 6034 may return to block 7316 and continue producing purified water.

[0242] Referring now primarily to the exemplary flowchart 7340 of FIG. 95, in the hot water production ready state, the set points of several different parameters of the system 6000 may be changed to a high temperature production set point for a period of time. This period of time may be a predetermined period of time, such as 10-20 minutes (e.g., 15 minutes). In some embodiments, each set point may be changed to its respective high temperature production set point for a (possibly predetermined) period of time specific to that set point. Among other parameter values, the speed of the compressor 6064 (see, e.g., FIG. 3) motor may be changed to a hot water production rate, for example, for a period of time. In some embodiments, the hot water production rate may be slower than that used in the normal purified water production state.

[0243] As shown, in block 7342, the controller 6034 may transition the system 6000 to a hot water production ready state. The controller may change the set points toward the respective hot water production set points in block 7344. As described above, the motor speed may be changed toward the hot water production motor speed. In addition, the blowdown reservoir fill rate may be changed toward the hot water production blowdown reservoir fill rate. The product temperature set point may be changed toward the hot water production temperature set point. To determine the rate of change, the above-mentioned time may be converted to the number of frames occurring over that time. The difference between the normal production set point and the hot water production set point may then be determined. This difference may then be divided by the number of frames to obtain a per-frame change increment. In block 7346, the difference between the current parameter value and the hot water production set point may be determined. If the difference between each set point is less than a predetermined threshold for the respective parameter in block 7348, the controller 6034 may transition to the next state in block 7350. This may be a hot water production state.

[0244] If, at block 7348, each difference is greater than a threshold value set for the respective parameter, the controller 6034 calculates a derivative at block 7351 based on data received from at least one temperature sensor in the system 6000. For example, the controller 6034 may calculate a derivative at block 7351 based on data received from the low pressure steam temperature sensor 6066. This derivative value may enable a determination of whether the temperature of the system 6000 is cooling or increasing at an undesirable rate. If, at block 7352, the derivative is outside a certain range, the controller 6034 may adjust (e.g., decrease) the rate of change of at least one parameter at block 7354. For example, the rate of change of the product temperature setpoint may be decreased. The rate of change may be limited to within a predetermined range for each setpoint. If the derivative value is within the acceptable range at block 7352 or if the rate of change has been adjusted at block 7354, the controller 6034 may check whether the timer for the hot water production ready state has expired. If the timer has not expired at block 7356, the controller 6034 may continue to change each parameter set point towards its respective hot water production state target at block 7344. If the timer has expired at block 7356, an error may be generated at block 7358.

[0245] In some embodiments, the hot water production state may be used in several modes. For example, the hot water production state may be used to provide hot water to a point-of-use device or system (e.g., medical system 6004 of FIG. 3 ) in communication with the system 6000. The hot water production state may also be used in a self-sanitizing mode, in which hot water may be passed from the purifier 6010 through various flow paths in the system 6000 for a predetermined period of time. In some examples, the self-sanitizing mode may only flow hot water through lines that are in direct valved communication with lines carrying purified product water. Specifically, the self-sanitizing mode may flow hot water through a bypass line to the drain 6018.

[0246] Referring now primarily to the exemplary flowchart 7360 of Figure 96, in a point-of-use hot water mode, a hot water production state may be entered at block 7362. The controller 6034 (see, e.g., Figure 3) may implement several controllers at block 7364. The controllers may be the same as those described above with respect to block 7314 of Figure 94, although different target set points, gains, feed forwards, etc. may be used.

[0247] A timer may be incremented at block 7366. If the product water level drops below a minimum at block 7368, the controller 6034 may transition the system 6000 to a standby state. Otherwise, the controller 6034 may continue to produce hot water for the point-of-use device or system until the timer increments above a threshold (e.g., 25-40 minutes) at block 7372. Once the timer increments above the threshold, the controller 6034 may transition the device to a standby state. In other embodiments, the controller 6034 may transition the system 6000 to a standby state when the controller 6034 receives a communication from the point-of-use device or system that the point-of-use device or system has completed its sanitization operation.

[0248] In the self-sanitizing mode, and then referring primarily to the exemplary flowchart 7380 of FIG. 97 , a hot production state may be entered at block 7382. The outlet to the point-of-use device or system may be closed at block 7384. The hot water produced by the system 6000 may be directed to the drain 6018 by the controller 6034. This may be done because self-sanitizing, if performed, typically occurs after the point-of-use device or system has performed its own sanitizing operation. As a result, any lines to the point-of-use device should already be sanitized by the hot water being output to the point-of-use device or system.

[0249] The controller 6034 (see, e.g., FIG. 3 ) may implement several controllers at block 7386. These controllers may be the same as those described above with respect to block 7314 of FIG. 94 , although different target set points, gains, feed forwards, etc. may be used. If the product level drops below a threshold at block 7388, the controller 6034 may transition the system 6000 to a standby mode at block 7390. Otherwise, the controller 6034 may receive temperature data signals from one or more product temperature sensors (e.g., 6082A-D of FIG. 3 ) and check the duty cycle of the diverter valve (e.g., 6084 of FIG. 3 ) at block 7392. If the temperature data signals at block 7394 indicate that the product temperature is above a threshold and a minimum amount of flow is present, a timer may be incremented at block 7396. Otherwise, the controller 6034 may return to block 7386. The minimum temperature may be 80° C. in one embodiment. The minimum temperature may be set at 10-20°C below the target temperature of the purified product water in the hot water production state. The duty cycle of the diverter valve 6084 (see, e.g., FIG. 3) may be required to be at least a certain value (e.g., 10-20%) for the controller 6034 to determine that a minimum amount of flow exists. When the timer increments above a threshold (e.g., 25-40 minutes), the controller 6034 may transition the system 6000 to a standby state at block 7390.

[0250] The hot water production state may have a timeout, for example, one hour or longer, after which the controller 6034 may transition the system 6000 to standby. This timeout may be used regardless of whether the system 6000 is in self-sanitizing mode or point-of-use hot water production mode.

[0251] 98, in the standby state, the system 6000 may be kept up to a certain temperature and ready to transition to producing purified water. Thus, the amount of time required to initiate production of purified water may be minimized. The standby state may be an intermediate state that the controller 6034 transitions the system 6000 into while waiting for a mode or state command from a point-of-use device or system (e.g., medical system 6004 of FIG. 3).

[0252] As shown in FIG. 98, a standby state may be entered at block 7412. In the standby state, the motor of the compressor 6064 (see, e.g., FIG. 3) may be turned off and the bearing feed pump may not operate. These may be turned off or disabled at block 7414. Additionally, the source proportioning valves 6050A, B (see, e.g., FIG. 3) to the purifier 6010 may be typically closed to maintain the water level in the purifier 6010. This may also be done at block 7414. At block 7416, the controller 6034 may control the heater to keep the water in the purifier 6010 at or within a target temperature (e.g., 111°C). The controller 6034 may also control the vent valve to maintain the low-pressure steam temperature target. A timer may be incremented at block 7417.

[0253] At block 7418, if the evaporator water level is below the threshold, the cooling valve gating the source flow to the electronics box 6046 may be closed. At block 7422, the source proportioning valves 6050A,B to the purifier 6010 may be opened to raise the evaporator water level to the target level. This may be done, for example, as described with respect to FIG. 86. If the evaporator water level is not below the threshold at block 7418, the controller 6034 may transition the system 6000 to the next state at block 7426 if the timer has incremented above the threshold at block 7424. Otherwise, the controller may return to block 7416.

[0254] The timer threshold may be a predetermined amount of downtime between two therapies in embodiments where the point-of-use device is a medical system 6004 (see, e.g., FIG. 3). In other embodiments, the controller 6034 does not automatically transition the system 6000 based on a timer; instead, the controller 6034 may transition when it receives a mode change request from the point-of-use device or system. The next state may be a normal purified water production state.

[0255] Referring now to FIG. 99 , an exemplary flowchart 6390 is shown detailing several operations that may be performed to control the liquid level in the system 6000. According to the flowchart 6390, the liquid level may be controlled to intentionally change over time in a predefined manner. Flow assessment may be performed by monitoring this intentional manipulation of the level in the output from a level sensing assembly that monitors the liquid level. If the intentional change is not reflected in the data collected from the level sensing assembly, it may be inferred that a blockage, pump problem, valve actuation problem, or similar condition may exist, and an error may be generated. The liquid level may additionally be controlled to a particular level setting, if desired, by moving away from intentional manipulation of the liquid level. In some embodiments, the controller 6034 (see, e.g., FIG. 2 ) may switch between an intentional level change mode and a level maintenance mode based on a predetermined basis.

[0256] The volume containing the liquid level to be maintained may be in fluid communication with a reservoir containing a level sensing assembly. The reservoir containing the level sensing assembly may be fluidly connected to and laterally disposed relative to the liquid volume to be controlled. The reservoir containing the level sensing assembly may be disposed such that, at least during a specific first state of operation of the purifier 6010, a portion of the reservoir is level with any point within a controllable or expected range of liquid level values. In some embodiments, the reservoir with the level sensing assembly may be disposed laterally, but have an inlet above the expected range of liquid level values ​​during a specific second state of operation of the purifier 6010. During the second state, liquid within the volume of the reservoir in which the level sensing assembly is disposed may boil or splash out of its expected range and enter the inlet.

[0257] In some embodiments, a level sensor may control the level of liquid in two fluidly connected volumes. For example, the level sensor may directly control the volume of liquid in a first volume in which the sensor is located and indirectly control the level of liquid in a second volume in fluid communication with the first volume (e.g., to an acceptable or expected operating level range, not necessarily an exact volumetric level). The first volume may include at least some points (e.g., an inlet from the second volume to the first volume) that are above the acceptable operating level range of liquid in the second volume. In certain operating conditions, such as the first condition described above, the expected ranges may differ, resulting in the liquid level in the second volume rising to at least the inlet of the first volume. In such situations, the level sensor may directly control the level of liquid in both the first and second volumes. This may occur, for example, when the purifier 6010 is first filled after start-up.

[0258] In a particular example, the measured liquid level may be the liquid level in the evaporator 6060 of the clarifier 6010. The level sensing assembly may be located in the blowdown reservoir (see, e.g., FIGS. 12-16, 63, and 66). Alternatively, the controlled liquid level may be the liquid level in the condenser 6076 of the clarifier 6010. The level sensing assembly may be located in the product reservoir 6012 (see, e.g., FIG. 37). In other embodiments, the level sensing assembly may be located in the evaporator reservoir (see, e.g., FIG. 59). In embodiments in which the level sensor measures two liquid levels, one directly and one indirectly, the directly sensed liquid level may be the liquid level in the blowdown reservoir 6014 (see, e.g., FIG. 2). The water level in the steam chest 6072 (see, e.g., FIG. 2) may be indirectly sensed via the liquid level sensed in the blowdown reservoir 601.

[0259] By way of example, flowchart 6390 is described assuming that the sensed water level begins above a minimum threshold and the outlet to the reservoir is opened to lower the water level. As shown, the controller 6034 of system 6000 (see, e.g., FIG. 2 ) may check the water level indicated by the water level sensing assembly on a predetermined basis at block 6392. This may be on a periodic, preset basis (e.g., at fixed time-based intervals) or, possibly additionally or alternatively, in response to the occurrence of one or more predetermined events (e.g., valve actuation, such as actuation of a source valve). At block 6394, the controller 6034 may determine whether the water level is below (or in some examples at or below) the minimum water level threshold. While the threshold described in connection with FIG. 99 is described as a percentage of the maximum water level of the expected or controllable range of water level, this need not be the case in all embodiments. The minimum water level or threshold may be a value between 40 and 50% (e.g., 47.5%) in some particular embodiments. In some other embodiments, the minimum water level may be between 30 and 40% (eg, 35%).

[0260] If the water level is at or below a minimum threshold, an outlet valve from the reservoir containing the water level sensing assembly may be actuated to a closed state by the controller 6034 at block 6396. The controller 6034 may also set a target water level at block 6396. The target water level may be set to a minimum water level, for example. The controller 6034 may check the water level on a predetermined basis at block 6398.

[0261] If the target is equal to or greater than the minimum target but less than the maximum target at block 6400, the target may be adjusted by the controller 6034 at block 6402. The maximum target may, in one example, be between 90% and 100% (e.g., 95%) of the reservoir volume. In this example, the target is adjusted upward according to a formula. The specific formula shown sets the new target equal to the following: Target current *t*rate

[0262] Here, Target current where ' is the current target value, 't' is the amount of time until the next water level sensing assembly level check, and rate is the desired amount of liquid per unit time to transfer to the reservoir containing the water level sensing assembly. This rate may be preset or may vary depending on the current state of the system 6000 (e.g., standby, water production, disinfection, etc.). In the context of a blowdown reservoir, this rate may be the concentrate production rate, which may be varied by changing the duty cycle of one or more source input valves. This rate may thus determine the amount of raw fluid entering the source input of the clarifier 6010. A fluid input control loop (see, e.g., FIGS. 100-101C) executed by the controller 6034 may regulate the operation of these valves.

[0263] The controller 6034 may check the water level from the water level sensor assembly on a predetermined basis at block 6404. If the water level is greater than or equal to the maximum water level at block 6406, the outlet valve to the reservoir may be opened and the target may be adjusted downward at block 6408. In this example, the target water level may be set to the minimum water level by the controller 6034 at block 6408. The maximum water level used may be equal to or below the maximum target water level. The maximum water level may be between 50 and 60% (e.g., 52.5%) or between 45 and 55% (e.g., 50%). Alternatively, the maximum water level may be between 4 and 20 percentage points greater than the minimum threshold.

[0264] At block 6410, if blocks 6392-6408 of flowchart 6390 have not been repeated a predetermined number of times, flowchart 6390 may return to block 6392 and repeat. This repetition may establish a cyclical rise and fall in the level of the liquid being controlled. This cyclical rise and fall may create a waveform that is generally sawtooth in nature when plotted over time. The period and shape of this waveform in the context of blowdown reservoir 6014 may depend on the concentrate production rate created by the fluid input command. In some embodiments, the predetermined number of repetitions may be one repetition. If blocks 6392-6408 have been repeated at least a predetermined number of times at block 6410, controller 6034 may check for the presence of an expected pattern (e.g., a sawtooth rise and fall) at block 6412. Assuming a waveform is present, the shape and period of the waveform may be verified against a nominal waveform expected for the current operating parameters (e.g., concentrate production). The nominal waveform may be determined empirically. If a pattern is detected as expected at block 6414, the flowchart 6390 may return to block 6392 and repeat. If a pattern is determined not to be present at block 6414, the controller 6034 may generate an error at block 6416.

[0265] In some embodiments, additional logic may be used, for example, to prevent the blowdown reservoir 6014 from draining in certain scenarios. The controller 6034 may, for example, inhibit the drain valve from opening if the fill level of the blowdown reservoir 6014 is below a certain amount. If the blowdown reservoir 6014 is empty or nearly empty, the drain valve of the blowdown reservoir 6014 may be inhibited from opening. Additionally, the controller 6034 may prevent the drain valve of the blowdown reservoir 6014 from opening if the pressure in the steam chest 6072 (e.g., as determined from a signal from sensor 6066 in FIG. 2 ) is below a predetermined value. Similarly, if the pressure exceeds a predetermined value and the water level in the blowdown reservoir 6014 exceeds a predetermined limit (e.g., the reservoir is full to the brim), the controller 6034 may disable the control loop and actuate the drain valve for the blowdown reservoir 6014 to an open position.

[0266] The controller 6034 may also track the amount of time that the drain valve to the blowdown reservoir 6014, for example, has been in an open position. If the drain valve to the blowdown reservoir 6014 remains open for more than a predetermined amount of time, an error may be generated at block 6416. The predetermined amount of time may be, for example, between 2 and 7 minutes (e.g., 5 minutes). The controller 6034 may also generate a notification if the reservoir has been draining for more than a second predetermined amount of time. The second predetermined amount of time may be less than the first amount of time. In some embodiments, the second predetermined amount of time may be between 1 and 3 minutes (e.g., 2 minutes).

[0267] The controller 6034 may also track the amount of time it takes for a reservoir, such as the blowdown reservoir 6014, to fill. For example, if the drain valve of the blowdown reservoir 6014 is closed and the water level in the blowdown reservoir 6014 is below the target level for more than a predetermined time limit, an error may be generated at block 6416. The predetermined amount of fill time may be, for example, between 5 and 15 minutes (e.g., 10 minutes). Alternatively, the predetermined amount of fill time may be at least twice the first predetermined amount of drain time. The controller 6034 may monitor for this additional fill time only when the system 6000 is in a particular operating state. For example, during a start-up state for hot water production (e.g., for disinfecting the medical system 6004), the controller 6034 may not generate an error if the predetermined amount of fill time is exceeded. Alternatively, a second predetermined amount of fill time greater than the first predetermined amount of fill time may be used in such operating state. If the blowdown reservoir water level sensor 6074 returns a value greater than a predetermined value designated as the maximum fill level, the controller 6034 may actuate the source valve supplying fluid to the purifier 6010 to a closed state.

[0268] 100-101C, several control diagrams 6420, 7020 are shown detailing exemplary control systems. These control systems may be used to control the temperature of one or more process streams in the system 6000 to a respective target temperature or temperature range by varying the flow rate of the input raw fluid through multiple process stream heat exchangers 6008A,B (see, e.g., FIG. 3). A controller 6034 (see, e.g., FIG. 2) may collect temperature data of at least one process stream exiting the multiple heat exchangers 6008A,B and use that data to divide the mass flow rate or total amount of incoming raw fluid between the heat exchangers 6008A,B. Because the input raw fluid is cooler than the output stream of the clarifier 6010, increasing the amount of input raw fluid flowing through the heat exchangers 6008A,B will lower the temperature of the process stream exiting the heat exchangers 6008A,B.

[0269] These control diagrams 6420, 7020 may be implemented, for example, in a system 6000 (see, e.g., FIG. 3) that produces purified product water for a destination system, such as a medical system 6004. The destination system may generate a temperature demand, which is provided as a target temperature or temperature range for the product process stream output from the system 6000, or this target temperature may be determined by the controller 6034, for example, in response to temperature measurements of the incoming raw fluid (see, e.g., FIG. 129). The product water may be controlled to a target temperature or temperature range by modifying the flow rate of raw water through the product and blowdown heat exchangers 6008A,B (see, e.g., FIGS. 6-9 or 56 and 57). In some examples, the temperature of the blowdown exiting the clarifier 6010 may be controlled to a target temperature in a similar manner to allow heat to be efficiently recovered by the system 6000 and reduce overall power consumption.

[0270] The illustrated control diagrams 6420, 7020 each include a fluid input control system or loop 6422 and a flow split control system or loop 6424. The fluid input control loop 6422 may control the total amount of raw water passing through the heat exchangers 6008A, B and entering the clarifier 6010. To do this, the fluid input control loop 6422 may adjust the total or accumulated amount of time that the source input valves are open over a given time interval. The flow split control system or loop 6424 may control the proportion of raw water that is directed through each of the heat exchangers 6008A, B. In other words, the flow split control loop 6424 may control the proportion of the total amount of open time (output by the fluid input control loop 6422) to be allocated to each individual source input valve.

[0271] With particular reference to the fluid input control loop 6422 of FIG. 100, a set point may be established based at least in part on a target blowdown level in the steam chest 6072 of the purifier 6010. A target level calculator 6426 may determine the target blowdown level in a manner similar to that described above in connection with FIG. 99 or below in connection with FIG. 104. This target level may be passed to a summer 6428. A current blowdown level, determined from data provided by the blowdown level sensor 6074, may also be provided to the summer 6428. The adders described herein, including adder 6428, combine their various inputs into an output, and the use of the word "adder" anywhere in this specification should not be interpreted to mean that only addition must be performed.

[0272] The difference between the current blowdown level and the target blowdown level may be determined in summer 6428. This output, or error value, may be passed to a PID controller 6430, which outputs a source duty cycle command 6432. The source duty cycle command 6432 may adjust the total or aggregate flow rate of source fluid into the system 6000. It should be noted that the gains used for the proportional, integral, and derivative terms of the PID controller 6430 may vary depending on the embodiment, and at least one may be set to zero in some cases (e.g., the derivative term).

[0273] In some embodiments, the fluid input control loop 6422 may receive data from a heater control loop (not shown in FIG. 100). For example, the fluid control loop 6422 may receive a duty cycle command issued to the heating element 6054. In response to the heating element duty cycle command, the fluid control loop 6422 may adjust its output. If the heating element duty cycle is above a predetermined threshold, the source duty cycle command 6432 may be attenuated. For example, if the heating element duty cycle is above a predetermined threshold (e.g., 100% duty cycle), the source duty cycle command 6432 may be set to zero or a fraction of the source duty cycle command 6432 generated from the fluid input control loop 6422. This may help avoid sudden cooling of the evaporator 6060 of the purifier 6010. Alternatively or additionally, the compressor speed may be increased upward as the heater duty cycle command increases.

[0274] With reference to the flow split control system 6424, the set points may be established based at least in part on a temperature request provided by the medical system 6004. This temperature request may vary depending on the operating mode or state of the medical system 6004. The medical system 6004 may have a first operating mode, a low temperature operating mode, and a second operating mode, a high temperature operating mode. The low temperature mode may be a therapy mode that generates a temperature request around or slightly below normal human body temperature (e.g., 20-30°C). The high temperature mode may be a disinfection mode that generates a temperature request at a temperature sufficient to cause disinfection of target components of the medical system 6004. The high temperature mode may be used for self-disinfection of the system 6000. The disinfection mode temperature requirement may depend on the intended contact time of the delivered product water and may be, for example, at least 60°C, but below the boiling point (e.g., 96°C). Alternatively, the destination system may set a production mode for the system 6000 instead of sending a specific temperature setpoint. The system 6000 may control the temperature to a setpoint or range defined for that mode. The system 6000 may also control the temperature to a setpoint or range defined for the state used by the controller 6034 in that particular mode. The various modes and states are described in detail elsewhere herein. The same source 6002 (see, e.g., FIG. 3) may be used in the low temperature mode and the high temperature mode. This source may be a fluid source whose temperature is not controlled. In some embodiments, the system 6000 may optionally draw from a hot water source (e.g., a residential hot water tank), particularly in the high temperature mode.

[0275] The temperature demand, along with the product or condensate output temperature determined from data provided by product output sensor 6082E, may be passed to summer 6436, which determines the difference between the two. The output of summer 6436 may then be passed to temperature PID controller 6438 to generate an output. It should be noted that the gains associated with the proportional, integral, and derivative terms of PID controller 6438 may vary depending on the embodiment. As with source PID controller 6430 (and all other PID controllers described herein), at least one of the gains for this PID controller may be set to zero (e.g., the derivative term).

[0276] At least one disturbance monitor 6440 may also be included in some embodiments. The disturbance monitor may provide data related to the monitored disturbance to a feed forward controller 6442. The feed forward controller 6442 may generate a disturbance compensation output that is passed to a summer 6444. If multiple disturbances are monitored, each disturbance may be associated with its own feed forward controller. Multiple compensation outputs from multiple feed forward controllers may be combined in a feed forward summer (not shown) before the combined compensation output is provided to the summer 6444. Alternatively, the feed forward controller 6442 may be based on a rough estimate of what the heat exchanger command should be. This rough estimate may be determined empirically. In such a case, the feed forward controller 6442 may enable the flow split control system 6424 to make adjustments more quickly to reach the target temperature under certain conditions. For example, such a feed-forward term may help the flow split control system 6424 quickly achieve a desired temperature set point after start-up.

[0277] The output of the temperature PID controller 6438 and the disturbance compensation output may be summed together in summer 6444 to generate a heat exchanger command 6446. The heat exchanger (HX) command 6446 may then be used to calculate the amount of incoming raw water to flow through each of the heat exchangers 6008A, B. In this exemplary embodiment, the heat exchanger command 6446 may be multiplied by the source duty cycle command 6432 in a product generator 6448. The resulting product may be used as a blowdown heat exchanger command 6450 (referenced as return HX in FIG. 100). The blowdown heat exchanger command 6450 may be subtracted from the original source duty cycle command in summer 6452 to obtain a product heat exchanger command 6454. The blowdown and product heat exchanger commands 6450, 6454 may be used to control the blowdown proportioning valve 6050B and the product proportioning valve 6050A, respectively. Through this proportioning, the temperature of the product water produced for the medical system 6004 and exiting the product heat exchanger 6008A may be controlled to meet temperature demands. When no product water is flowing through the product heat exchanger, all of the raw water may be sent through the blowdown heat exchanger. Alternatively, in some embodiments, a small percentage of the raw water may continue to flow through the product heat exchanger 6008A.

[0278] Referring now to the exemplary control diagram 7020 shown in FIGS. 101A-C, the fluid input control loop 6422 may be a multi-mode control loop. In such an embodiment, the fluid input control loop 6422 may output multiple interim values ​​for the source duty cycle command. These values ​​may then be used to determine a single source duty cycle command 7050. This single source duty cycle command 7050 may be a blended command made up of two or more of the interim values. When such a blended command is used, the contribution of each interim command to the single source duty cycle command may be weighted. For example, a first interim command of 30% may be added to a second interim command of 70% to arrive at the single source duty cycle command 7050. The percentages may be changed during operation based on changes in operating conditions or modes, sensor data, communications from a point-of-use system, etc. The controller 6034 of the system 6000 may use one of the tentative commands as the single source duty cycle command 7050, and none of the other tentative commands affect the single source duty cycle command 7050. In other words, 100% of one tentative command and zero% of the other command may be added together to generate the single source duty cycle command 7050.

[0279] In some embodiments, the number of interim source command duty cycles may equal the number of modes or states in which the purifier 6010 may produce purified water. For example, the controller 6034 may produce purified water in a high temperature mode (e.g., for disinfection of the medical system 6004 or the system 6000 itself) and in a normal mode. In such an embodiment, as shown in FIG. 101A, the fluid input control loop 6422 may output interim values ​​for each of these production modes. While two are described in connection with FIG. 101A, a greater number of interim commands may be generated in other embodiments.

[0280] As shown, a set point or source duty cycle command 7050 for the fluid input control loop 6422 may be established based in part on a target blowdown rate from the clarifier 6010. A target rate calculator 7022 may determine the target blowdown rate (as further described in connection with FIG. 104). In other embodiments, the target rate may be a predetermined value. This target rate may be passed to a summer 7023. A current blowdown rate 7024, determined from data provided by the blowdown level sensor 6074, may also be provided to the summer 7023 (as further described in connection with FIGS. 102-103). In the summer 7023, a difference between the current blowdown rate 7024 and the target blowdown rate may be determined. This output, or error value, may be passed to a PID controller 7025, which outputs a first tentative source duty cycle command to a summer 7026. It should be noted that the gains used for the proportional, integral, and derivative terms of the PID controller 7025 may vary depending on the embodiment, and at least one may be set to zero in some cases (e.g., the derivative term).

[0281] In some embodiments, the PID controller 7025 may modify its output value based on a feed-forward term before passing the first interim duty cycle command to the summer 7026. This feed-forward term may be based on the amount of the source duty cycle command pre-allocated to recover heat from the blowdown passing through the blowdown heat exchanger 6008B. For example, the pre-allocated source duty cycle command for the source blowdown proportioning valve 6050B may be subtracted from the output value of the PID controller 7025, and the result may be passed to the summer 7026. In some embodiments, a minimum amount of incoming raw water may be required to flow through the blowdown heat exchanger 6008B, and the blowdown temperature may be controlled to a predetermined range by modifying the amount of raw water flowing through the blowdown heat exchanger 6008B (see, for example, FIG. 132). The feed forward term may pre-allocate a portion of the source duty cycle command generated by the PID controller 7025 to ensure a minimum amount of source flow through the blowdown heat exchanger 6008B, allocating a certain amount of duty cycle to achieve control to the desired temperature. If the electronics box 6064 (see, e.g., FIG. 3) can be cooled by the incoming raw water directed to the blowdown heat exchanger 6008B (see, e.g., FIG. 131), the feed forward term may similarly pre-allocate a portion of the incoming raw water for this purpose.

[0282] In one embodiment, as shown in FIG. 101A , the fluid input control loop 6422 may also generate a second interim source duty cycle command. This second interim source duty cycle command may be based in part on a target blowdown rate for hot water production. A target hot water production blowdown rate calculator 7052 may determine the target rate. Alternatively, the target blowdown rate for this mode may be a predetermined value. This target rate may be passed to a summer 7054. The current blowdown rate 7024 may also be provided to the summer 7054. The summer 7054 may determine the difference between the current blowdown rate and the target. This output, or error value, may be passed to a high temperature production PID controller 7056, which provides an output to a summer 7058. It should be noted that the gains used for the proportional, integral, and derivative terms of the high temperature production PID controller 7056 may vary depending on the embodiment, and at least one may be set to zero in some cases (e.g., the derivative term).

[0283] The second tentative source duty cycle command may be based in part on a target evaporator water level during hot water production. The evaporator target water level 7060 may be a predetermined value in some embodiments. This target water level may be provided to a summer 7064. A current evaporator water level 7062, determined from data provided by the evaporator water level sensor 6073 (see, for example, FIG. 3 ), may also be provided to the summer 7064. The summer 7064 may determine the difference between the current evaporator water level 7062 and the target water level 7060. This output, or error value, may be provided to an evaporator controller 7066, which provides an output to a summer 7058. The summer 7058 may combine the output of the evaporator controller 7066 with the output of the hot water production PID controller 7056 into a second tentative source duty cycle command, which may be provided to a summer 7036.

[0284] In some embodiments, the evaporator controller 7066 may be a PID controller. It should be noted that the gains used for the proportional, integral, and derivative terms of the evaporator controller 7066 may vary depending on the embodiment, and at least one may be set to zero in some cases. The evaporator controller 7066 may be primarily a derivative controller. In some embodiments, the evaporator controller 7066 may be a PD controller in which the gain for the P term is significantly smaller (e.g., by one to two orders of magnitude or more) than the gain for the D term. The target evaporator water level may also be used to generate a first tentative source duty cycle command (not shown), as described immediately above.

[0285] In some embodiments, the fluid input control loop 6422 may also receive data from the heater control loop. For example, the fluid control loop 6422 may receive a target sump temperature 7028 and a current sump temperature 7030 and provide them to a summer 7032, which determines the difference between their values. Depending on the value of the target sump temperature 7028, the current sump temperature 7030, and / or the difference, the fluid control loop 6422 may adjust its output. The decision to make an adjustment may be made by the controller 6034, for example, as described in connection with FIGS. 105A-B. If an adjustment is made, the sump regulator controller 7034 may generate an adjustment output based on the input from the summer 7032. The sump regulator controller 7034 may be a PID loop. Depending on the embodiment, the gains for one or more of the terms in the PID loop may be set to zero. For example, the sump regulator controller 7034 may set the gains of the integral and derivative terms to zero. In such an embodiment, the sump regulator controller 7034 may act as a P controller. The output from the sump regulator controller 7034 may be provided to two summers 7036, 7026.

[0286] Additionally, in some embodiments, the fluid input control loop 6422 may also receive data from the compressor motor control loop. For example, the fluid control loop 6422 may receive a target low-pressure steam temperature 7038 and a current low-pressure steam temperature 7040. These values ​​may be provided to a summer 7042, which determines the difference between the values. Depending on the target low-pressure steam temperature 7038, the current low-pressure steam temperature 7040, and / or the value of the difference, the fluid control loop 6422 may adjust its output. The decision to make an adjustment may be made by the controller 6034, for example, as described in connection with FIGS. 105A-B. If an adjustment is made, a low-pressure steam regulator controller 7044 may generate an adjustment output based on the input from the summer 7042. The low-pressure steam regulator controller 7044 may be a PID loop. Depending on the embodiment, the gain for one or more of the terms in the PID loop may be set to zero. For example, the low pressure steam regulator controller 7044 may set the gains of the integral and derivative terms to zero. In such an embodiment, the low pressure steam regulator controller 7044 may act as a P controller. The output from the low pressure steam regulator controller 7044 may be provided to two summers 7036, 7026. Any adjustments from the sump regulator controller 7034 and the low pressure steam regulator controller 7044 may be used to modify first and second interim duty cycle commands in summers 7026 and 7036, respectively. After the adjustments, if any, are made, the interim duty cycle commands may be provided to a slider 7048.

[0287] The slider 7048 may allow the source duty cycle command 7050 output from the source input control loop 6422 to be a mix of the different tentative source commands generated by the source input control loop 6422. The slider 7048 may also allow one of the tentative source duty cycle commands to be ignored. For example, when the system 6000 is in a high temperature purified water production mode or state, the first tentative source duty cycle command may have little, if any, effect on the source duty cycle command 7050. Similarly, when the system 6000 is in a normal purified water production mode or state, the second tentative source duty cycle command may have little, if any, effect on the source duty cycle command 7050. During the transition between the two modes or states, the slider 7048 may slowly adjust the command from purely or primarily one of the tentative duty cycle commands to purely or primarily the other of the tentative duty cycle commands. This adjustment may be based, for example, on a predetermined increment per frame. A similar slider 7018 (see FIG. 101C) may be used for the tentative source proportioning command for the product heat exchanger 6008A.

[0288] Using the example of a tentative source command for a high temperature mode or state and a tentative source command for a normal mode or state, the controller 6034 may determine a high temperature ratio and a normal ratio for use by the slider 7048. The tentative source command may then be multiplied by the respective ratios and then added together to determine the source duty cycle command 7050. When in normal mode, the high temperature mode ratio may be zero. When in high temperature mode, the normal mode ratio may be zero. During a transition from one mode to another, the ratio of the new mode may be incremented according to the change rate limit, and the ratio of the old mode may be decremented according to that limit. This may continue, in some examples, until the ratio of the new mode has been incremented to 100% and the ratio of the old mode has been decremented to 0%.

[0289] With reference to the flow split control system 6424, the set point may be established based, at least in part, on a temperature request or production mode setting provided from a point-of-use system, such as the medical system 6004. This temperature request or production mode setting may vary depending on the operating mode or state of the medical system 6004. The controller 6034 of the system 6000 may determine a target temperature 7068 from the temperature request or production mode setting 7065. The target temperature may, in one example, be determined as described in connection with FIG. 129.

[0290] At block 7069, if the system 6000 is currently in normal water production mode, the target temperature 7068, along with a product or condensate output temperature 7070 determined from data provided by a product output sensor (e.g., one or more of sensors 6082A-D of FIG. 3), may be passed to a summer 7072, which determines the difference between the two. The output of summer 7072 may then be passed to a temperature PID controller 7074 to generate an output. It should be noted that the gains associated with the proportional, integral, and derivative terms of the temperature PID controller 7074 may vary depending on the embodiment. At least one of the gains for the temperature PID controller 7074 may be set to zero (e.g., the derivative term).

[0291] The output of the temperature PID controller 7074 may be limited to minimum and maximum values ​​in limiter 7076 to generate a product heat exchanger command 7078. At block 7080, if the system 6000 is in a normal production mode or state, the product heat exchanger command may be subtracted from the total source duty cycle command 7050 in summer 7082. The remaining portion of the source duty cycle command 7050 or the commanded source flow may be assigned to a blowdown heat exchanger command 7084. The output of summer 7082 may be limited to minimum and maximum values ​​by limiter 7086 before being set as the blowdown heat exchanger command 7084.

[0292] In some embodiments, as shown in FIG. 101C, some amount of source duty cycle command may be pre-allocated for the blowdown heat exchanger 6008B. This may allow for more heat recovery and more efficient cooling of the electronics box 6046 in the system 6000, among other things. Further explanation is provided above and in connection with FIG. 132. This pre-allocated command may be added to the output of adder 7082 in block 7083. The output of block 7083 may be limited to minimum and maximum values ​​by limiter 7086 before being set as the blowdown heat exchanger command 7084.

[0293] When the system 6000 is in a hot water production mode or state, the total source command duty cycle 7050 or commanded source flow may be assigned (after restriction by restrictor 7086) to the blowdown heat exchanger command 7084. The product heat exchanger command 7078 may be independent of the source input control loop 6422. A restrictor 7077 for the product heat exchanger command 7078 in a hot water production mode or state may limit the product heat exchanger command to a low value (e.g., less than 5%, or in some embodiments, 2% duty cycle) to prevent additional incoming raw fluid (in addition to that required by the source input control loop 6422) from having a problematic effect on the control of the blowdown rate.

[0294] In some embodiments, as shown in Figure 101C, the target temperature 7071 may be passed along with the product or condensate output temperature 7070 to a summer 7073, where the difference between the two is determined. The output of summer 7073 may then be passed to a high temperature PID controller 7075 to generate an output. It should be noted that the gains associated with the proportional, integral, and derivative terms of high temperature PID controller 7075 may vary depending on the embodiment. At least one of the gains for the high temperature PID controller 7075 may be set to zero (e.g., the derivative term). A limiter 7077 for the product heat exchanger command 7078 in the high temperature production mode or state may limit the product heat exchanger command in a similar manner as described above. A slider 7081 such as that described in connection with FIG. 101A may be used to facilitate a smooth transition of the product heat exchanger command 7082 as the system 6000 moves from a normal temperature water production state to a hot water temperature production state.

[0295] The blowdown and product heat exchanger commands 7078, 7084 may be used to control the blowdown proportioning valve 6050B and the product proportioning valve 6050A (see, e.g., FIG. 3), respectively. Through this proportioning, the temperature of the product water produced for the medical system 6004 and exiting the product heat exchanger 6008A may be controlled to a temperature target.

[0296] 102, a flowchart 6820 is shown detailing some example operations that may be performed to determine the fill rate of a reservoir and control the outlet valve to the reservoir. In an embodiment, the reservoir may be the blowdown reservoir 6014 (see, for example, FIG. 3) of the system 6000. The flowchart 6820 is described as starting with the sensed reservoir water level at a minimum level immediately after the reservoir finishes draining.

[0297] As shown, at block 6822, the controller 6034 (see, e.g., FIG. 3 ) may set the minimum water level value as the current water level value. The water level value may be read from a reservoir level sensor, such as blowdown level sensor 6074 if the reservoir is blowdown reservoir 6014. At block 6824, the controller 6034 may check the liquid level in the reservoir. This may occur on a predetermined basis, for example, every second or every number of seconds. At block 6826, if the liquid level is below the minimum value set at block 6822, the flowchart 6820 may return to block 6822 and set the minimum value as the current water level. If the water level is above the minimum water level at block 6826, a timer may be incremented at block 6828. If the timer has not incremented above the threshold at block 6830, the controller 6034 may continue checking the liquid level and return to block 6824. If the timer increments above the threshold value at block 6830, the controller 6034 may determine the fill rate of the reservoir at block 6832. Depending on the embodiment, the threshold may be predetermined and may be 0.025 to 2 seconds or thereabouts (e.g., 0.5 seconds). The rate may be determined by determining the difference between a value related to the previous level and the current level in the reservoir. This difference may then be converted to a rate using the time elapsed since the previous level value was collected. The fill rate value may be prohibited from falling below zero. If the fill rate value falls below zero, the fill rate value may be reset to zero. The fill rate may be passed to a filter at block 6834. The filter may be a low-pass filter.

[0298] If the storage tank is filling at block 6836, and if the storage tank fill rate is greater than or equal to the maximum fill value at block 6838, the storage tank outlet valve may be opened at block 6840. The storage tank may then be drained. The inlet source valve may be closed if the outlet to the storage tank is open. If the system is producing hot water, the valve controlling the flow of incoming raw water through the product heat exchanger to the purifier 6010 may be commanded to close. Alternatively, the valve may be opened at a low duty cycle, which may be less than 10% (e.g., 2% or 5% or less). The maximum fill value may be the same as the maximum threshold described above in connection with FIG. 99 above. As the storage tank drains, the water level in the storage tank may be che...

Claims

1. 1. A distillation device comprising: a raw fluid input; a compressor that receives source steam and delivers compressed steam; A purifier, an evaporator in fluid communication with the raw fluid input, the evaporator converting a portion of the received raw fluid into vapor; a purifier comprising a condenser that receives compressed vapor from the compressor and converts the compressed vapor into a product liquid; a heat exchanger in fluid communication with the raw fluid input; The heat exchanger is an outer tube having an outer diameter; at least one inner tube located within and generally aligned with said outer tube; a terminator at each end of the heat exchanger, a first terminator in fluid contact with the raw fluid input and a second terminator in fluid contact with the purifier; The terminator is a first port in fluid communication with the outer tube, the first port having a first port structure, the first port structure sealing against the outer tube, the first port structure having at least one opening for receiving the at least one inner tube; a second port in fluid communication with the at least one inner tube, the second port having a second port structure, the second port structure including at least one opening for receiving the at least one inner tube; a first seal within the at least one opening of the first port structure; and a second seal within the at least one opening of the second port structure; and a housing connecting the first port structure and the second port structure; The housing comprises: a chamber in fluid communication with an exterior of the at least one inner tube between the first seal and the second seal; a leak port in fluid communication with the chamber and the ambient environment. Distillation device.

2. the first port structure: a thin ring having an inward protrusion, the inner diameter of the inward protrusion being greater than the outer diameter of the outer tube; a tapered ring adjacent to and concentric with said thin ring, said tapered ring having an inwardly tapering surface; a threaded element engaging the housing and contacting the thin ring; Rotating the threaded element forces the thin ring against the inwardly tapering surface, thereby forcing the inward projection into contact with the outer diameter of the outer tube. The distillation device of claim 1 .

3. the first port structure further comprising an O-ring adjacent the tapered ring and located on the opposite side of the tapered ring from the thin ring, the O-ring forming a radial seal on the outer diameter of the outer tube. The distillation device of claim 2 .

4. the terminator further comprising a threaded element securing the second port structure to the housing, the second port structure being unfixed to the housing and rotatable on a longitudinal axis of the housing; The distillation device of claim 1 .

5. 1. A distillation device comprising: a raw fluid input; a compressor that receives source steam and delivers compressed steam; A purifier, an evaporator in fluid communication with the raw fluid input, the evaporator converting a portion of the received raw fluid into vapor; a purifier comprising a condenser that receives compressed vapor from the compressor and converts the compressed vapor into a product liquid; a heat exchanger in fluid communication with the raw fluid input; The heat exchanger comprises: an outer tube having an outer diameter; at least one inner tube located within and generally aligned with said outer tube; a terminator at each end of the heat exchanger, a first terminator in fluid contact with the raw fluid input and a second terminator in fluid contact with the purifier; The terminator is a first port in fluid communication with the outer tube, the first port having a first port structure, the first port structure comprising: a toothed thin ring having inward projections, the inner diameter of the inward projections being greater than the outer diameter of the outer tube; a tapered ring adjacent said ring and having an inwardly tapering surface; a first port including a threaded element engaging a housing and contacting the toothed thin ring, and an O-ring adjacent to and positioned on the opposite side of the tapered ring from the thin ring, forming a radial seal on the outer diameter of the outer tube; a second port in fluid communication with the at least one inner tube, the second port having a second port structure, the second port structure including at least one opening for receiving the at least one inner tube; the housing connecting the first port structure and the second port structure, wherein rotation of the threaded element of the first port structure forces the toothed thin ring against the inwardly tapering surface, thereby forcing the inward protrusion into contact with the outer diameter of the outer tube. Distillation device.

6. The terminator is a first seal within at least one opening of the first port structure; a second seal within the at least one opening of the second port structure; and Furthermore, the housing includes a chamber in fluid communication with the at least one inner tube between the first seal and the second seal, and a leak port in fluid communication with the chamber and an ambient environment. The distillation device of claim 5.

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