Water purification device and method for controlling at least one fluid characteristic in a water purification device

Abstract

To provide a water purifier, a peritoneal dialysis system equipped with the water purifier, and a method for controlling at least one fluid property in the water purifier.SOLUTION: A water purifier 300 includes a reverse osmosis device 301, a reverse osmosis pump 450, a recirculation path 375, a water purification path 371, a heater 302, a temperature sensor 303, and a control unit 112. The peritoneal dialysis system includes: the water purifier; and a peritoneal dialysis (PD) cycler arranged and configured to use PD fluid during PD treatment, in which the PD fluid is mixed using product water from the water purifier. The method of controlling fluid properties includes detecting at least one fluid property of purified water in the water purification path based on the at least one detected fluid property, and adjusting a flow rate of water in the recirculation path to meet one or more predetermined criteria of the purified water in the water purification path.SELECTED DRAWING: Figure 4a

Description

Technical Field

[0001] The present disclosure relates to a water purification device and a corresponding method for controlling at least one fluid property in the water purification device. The present disclosure also relates to a computer program and a computer program product for implementing this method.

Background Art

[0002] In the treatment of patients suffering from acute or chronic renal failure, dialysis therapy is used. The three general categories of dialysis therapy are hemodialysis (HD), peritoneal dialysis (PD), and continuous renal replacement therapy (CRRT).

[0003] In hemodialysis, the patient's blood is purified by a passage through an artificial kidney in an extracorporeal membrane system incorporated in a dialyzer. Blood treatment includes extracorporeal circulation through a semipermeable membrane (dialyzer) that circulates the patient's blood on one side of the membrane and an exchanger, and circulates a dialysate containing the main electrolytes of the blood at a concentration close to that in the blood of a healthy person on the other side. Further, a pressure difference is created between the two compartments of the dialyzer separated by the semipermeable membrane, and as a result, a small amount of plasma fluid passes through the membrane by ultrafiltration and enters the compartment containing the dialysate.

[0004] CRRT is used as an alternative therapy for patients whose condition is too severe or unstable for standard hemodialysis. This is similar to hemodialysis and utilizes a semipermeable membrane for diffusion and some degree of convection. However, it is a slower blood treatment than hemodialysis and may proceed continuously for several hours to several days.

[0005] In peritoneal dialysis, dialysate is infused into the patient's abdominal cavity. This cavity is lined by the peritoneum, which is highly vascularized. Metabolic products are removed from the patient's blood by diffusing across the peritoneum into the dialysate. Excess fluid, i.e., water, is also removed by osmosis induced by hypertonic dialysate. To maintain the patient's body fluid volume and composition within appropriate limits through these two processes of diffusion and osmotic ultrafiltration, it is necessary to remove an appropriate amount of solute metabolic products and fluid.

[0006] There are various types of peritoneal dialysis therapies, such as continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD), including tidal APD, continuous flow peritoneal dialysis (CFPD), etc.

[0007] CAPD is a manual dialysis treatment. The patient manually connects an implanted catheter to the drain and drains the used dialysate from the abdominal cavity. Then, the patient connects the catheter to a new bag of dialysate and infuses the new dialysate into the patient through the catheter. The patient disconnects the catheter from the fresh dialysate bag, allowing the dialysate to remain in the abdominal cavity where the transfer of waste, toxins, and excess water occurs.

[0008] Automated peritoneal dialysis (APD) is similar to CAPD in that the dialysis treatment includes drain, fill, and dwell cycles. However, APD devices typically perform the cycles automatically while the patient is asleep. The APD device liberates the patient from having to perform the treatment cycles manually and from having to carry supplies during the day. The APD device is fluidly connected to an implanted catheter, a source or bag of fresh dialysate, and a liquid drain. The APD device pumps fresh dialysate from the dialysate source into the patient's peritoneal cavity through the catheter, where the dialysate dwells, allowing for the transfer of waste, toxins, and excess water. The APD device drains the used dialysate from the peritoneal cavity through the catheter into the drain. As in the manual process, drain, fill, and dwell cycles occur several times during APD. A "last fill" often occurs at the end of CAPD and APD, which remains in the patient's peritoneal cavity until the next treatment.

[0009] Both CAPD and APD are batch systems that drain used dialysate to a drain. A tidal system is a modified batch system. In tidal, instead of removing all the liquid from the patient over a longer period, a portion of the liquid is removed and replaced after a short period of time.

[0010] A continuous flow or CFPD system cleans or regenerates used dialysate instead of discarding it. CFPD systems are generally more complex than batch systems.

[0011] CAPD, APD (including tidal), and CFPD systems can use a pumping cassette. The pumping cassette typically includes a flexible membrane that mechanically moves back and forth to draw and push dialysate in and out of the cassette.

[0012] In one form of peritoneal dialysis, a cycler is used to infuse and drain dialysis fluid. This form of treatment may be performed automatically during the night while the patient is asleep. The cycler measures the amount of fluid infused and the amount removed to calculate net fluid removal. The treatment procedure typically begins with an initial drain cycle to empty the peritoneal cavity of used dialysis fluid. The cycler then performs a series of fill cycles, dwell cycles, and drain cycles, typically ending with a fill cycle.

[0013] Peritoneal dialysis generally requires large volumes of dialysis fluid. Typically, for each application, or exchange, a given patient will infuse 2 to 3 liters of dialysis fluid into the peritoneal cavity. The dialysis fluid is left to dwell for approximately 1 to 3 hours, at which point it is drained and replaced with fresh dialysis fluid. Typically, such exchanges are performed 4 times per day. Thus, each patient requires approximately 8 to 20 liters of dialysis fluid per day, 7 days a week, 365 days a year.

[0014] Dialysis fluid has conventionally been provided in sealed container bags for use in the above treatment and is made ready for use. For example, peritoneal dialysis is typically performed using bags containing three different concentrations of glucose. These bags are delivered to the patient's home as 1-liter to 6-liter bags with different glucose concentrations. The normal daily consumption is about 8 to 20 liters of PD dialysis fluid. The liquid is placed in a sterile bag of up to 6 liters in size, packed in a box, and delivered to the patient's home for use, for example, monthly. The boxes of liquid are cumbersome and heavy for PD patients to handle and can consume substantial space in the home. Also, the bags and boxes generate waste that is processed in relatively large quantities on a weekly or monthly basis.

[0015] Based on the above, several problems become apparent. Shipping and storing large volumes of liquid requires space consumption. Further, using multiple pre-filled bags generates waste in the form of empty containers and packaging.

[0016] Accordingly, a subsystem for the entire peritoneal dialysis (PD) system for creating a dialysis solution at the point of use, e.g., in a PD device, is required.

[0017] The PD dialysate is delivered directly to the patient's abdominal cavity. Accordingly, the PD fluid requires a sterilization level suitable for introduction into the patient's peritoneum. Correspondingly, typically prior to delivery to the point of use, usually the patient's home, the PD dialysate is premixed and sterilized.

[0018] Also, in hemodialysis and CRRT, a system for creating a dialysis solution at the point of use, e.g., a hemodialysis device or a CRRT device, is accordingly required.

[0019] In some embodiments, the overall system for hemodialysis, PD, or CRRT includes three main components, namely, a dialysis device, a water purifier, and a water supply set that operates with both the dialysis device and the water purifier. The dialysis device is, for example, a PD cycler, a hemodialysis device, or a CRRT device. The dialysis device prepares and concentrates the dialysis solution from water purified by the water purifier.

[0020] The water purifier produces purified water from, for example, tap water, at the time of use of the purified water. SUMMARY OF THE INVENTION

[0021] Under certain circumstances, it is desirable to deliver a product water flow of a certain magnitude. For example, it is possible to deliver a timely fixed amount of purified water or to overcome the pressure drop caused by a filter disposed downstream of the water purification device. However, the hardware of the water purification device and the filter may deteriorate over time. For example, a sterilization-grade filter can be blocked by bacteria and endotoxins and possibly other substances. This can affect the product water flow from the water purification device. As a result, the processing capacity for a given pressure will decline over time. Thus, the amount of purified water produced by the water purification device may be uncertain. Accordingly, one objective of the disclosure is to control the characteristics of the product water flow, for example, to maintain a constant (or fairly constant) flow rate or pressure. Another objective is to keep the operating points (e.g., pressure, temperature, or flow rate) of the components within the water purification device within a certain range.

[0022] These objects and others are at least partially achieved by the apparatus and methods according to the independent claims and by the embodiments of the dependent claims.

[0023] According to a first aspect, the disclosure relates to a water purification apparatus for producing purified water. The water purification apparatus includes a reverse osmosis (RO) apparatus, an RO pump, a recirculation path, a purified water path, a purified water path, a control device, at least one detector, and a control unit. The reverse osmosis (RO) apparatus is arranged to produce a purified water stream, and the RO apparatus includes a supply port including a supply port arranged to receive feed water and a purified water outlet, and the RO pump is arranged to send feed water to the supply port. Further, a recirculation path is arranged to recirculate a portion of the purified water stream from a first point downstream of the RO apparatus to a second point upstream of the RO apparatus, and a purified water flow path is arranged to convey purified water from the purified water outlet to a product water port. The purified water path includes a product water path arranged downstream of the recirculation path for conveying product water to the product water port. The control unit is configured to control the control device to adjust the flow rate of the purified water in the recirculation path based on the fluid characteristics detected by at least one detector. At least one detector is arranged to detect the product fluid characteristics of the product water in the product water path. Also, the control unit is configured to control the control device to control the production fluid characteristics of the product water in the product water path to meet one or more predetermined product water criteria based on the production fluid characteristics detected by at least one detector. At least one detector includes a flow rate sensor, and the product fluid characteristics detected by the flow rate sensor are the flow rate of the product water in the production water flow path. Also, one or more predetermined product water criteria include that the flow rate of the product water in the product water path corresponds to a predetermined flow rate.

[0024] Accordingly, one or more fluid characteristics in the purified water path of the water purification apparatus can be controlled. More specifically, the one or more product fluid characteristics of the product water of the dialysis apparatus can be controlled such that the desired product fluid characteristics are maintained throughout production and also, for example, during start-up and shutdown. Here, the desired flow rate of the product water can be maintained over time.

[0025] According to some embodiments, at least one detector comprises a pressure sensor, the product fluid characteristic detected by the pressure sensor is the pressure of the fluid in the product water path, and one or more predetermined product water standards include that the pressure of the product water in the product water path remains below a predetermined upper pressure level and / or the pressure of the product water in the product water path corresponds to a predetermined pressure. Accordingly, the pressure of the product water in the product water path can be controlled to remain within a desired range for optimal operation. Thus, it is possible to avoid components from being damaged or deteriorated due to the pressure in the product water path being too high.

[0026] According to some embodiments, at least one filter is arranged to filter the product water flowing through the product water path, and the predetermined upper pressure level corresponds to the pressure tolerance level of at least one filter or any other component arranged in the product water path.

[0027] Since water is sent through the filter, bacteria and endotoxins, other substances may possibly reduce the permeability of the filter arranged in relation to the product water path. This means that the processing capacity for a certain pressure will decrease over time. By using the proposed method, the pressure of the product water in the product water path can be increased up to the maximum allowable level to compensate for such behavior.

[0028] According to some embodiments, the control unit is configured to activate an alarm function in response to a change in at least one product fluid characteristic detected by at least one detector. Thus, it is possible to warn the operator or the patient if a suspected error is detected.

[0029] According to some embodiments, the control unit is configured to control the control device to obtain a predetermined flow rate through the product water port during a predetermined time period in order to produce a predetermined amount of water. Thus, the dialysis device can produce the amount of product required. The required amount is typically from 0.5 to 400 liters, for example 1, 2, 5, 10, 20, 50, 70, 90, 150, 200 or 300 liters.

[0030] According to some embodiments, the water purification device includes a heater arranged to heat the product water flowing in the product water path. Thus, the dialysis device can produce product water at the required temperature. The heater can also be used to control the temperature of the RO membrane of the RO device.

[0031] According to some embodiments, the water purification device comprises a temperature sensor arranged to measure the water temperature in the water purification path downstream of the heater. According to these embodiments, the control unit is configured to control the control device to control the temperature of the water flowing through the RO membrane of the RO device based on the temperature detected by the temperature sensor. Thus, the temperature of the RO membrane can be kept fairly constant, which would be desirable for operation.

[0032] According to some embodiments, the water purification device includes a tank arranged to receive water from an external water source and supply water to the supply port.

[0033] According to some embodiments, the water purification device includes a polisher arranged downstream of the recirculation circuit in the water purification path. For example, the polisher includes an electro-deionization device (EDI).

[0034] According to some embodiments, the water purification device includes a permeate path arranged to convey the purified water from the purified water outlet of the RO device to the inlet of the polisher.

[0035] According to some embodiments, the product water path is arranged to convey the purified water from the outlet of the polisher to the product water port.

[0036] According to a second aspect, the disclosure relates to a corresponding method for controlling at least one fluid property in a water purification device that produces purified water. The water purification device includes a reverse osmosis device (RO device), produces a purified water stream, and includes a recirculation path arranged to recirculate a portion of the purified water stream from a point downstream of the RO device to a point upstream of the RO device. The method includes detecting at least one fluid property of the purified water in the purified water path, including detecting at least one fluid property of the purified water in the product water path of the purified water path, where the product water path is arranged downstream of the recirculation path, and detecting the flow characteristics of the product water in the purified water path, including adjusting the flow rate of the water in the recirculation path to meet one or more predetermined criteria for the purified water in the purified water path. The method includes detecting the flow characteristics of the product water in the product water path of the product water path. The at least one product fluid property includes the flow rate of the product water in the product water path, and the one or more predetermined product water criteria include that the flow rate of the water in the product water path corresponds to a predetermined flow rate.

[0037] Thus, as described above, the product fluid properties can be controlled to meet certain criteria defined, for example, by the manufacturer or the user. Therefore, water production can be more effective, and dialysis treatment can be safe. This method also makes it possible to change the product water flow rate smaller and more quickly, only when adjusting the pump appearance frequency used to supply water to the RO device.

[0038] According to some embodiments, the method includes estimating the amount of product water produced during a production time period based on the duration of the production time period and estimating the corresponding flow rate of the purified water detected during the production time period. The ability to control the pressure makes it possible to avoid the high pressure in the product water path that may cause damage in the worst case.

[0039] According to some embodiments, the method includes triggering a predetermined action when the amount reaches a predetermined production amount. For example, an alert signal or an action (e.g., a message sent to a dialysis device) may be triggered when the required volume has been produced.

[0040] According to some embodiments, at least one production fluid characteristic includes the pressure within the product water path, and one or more predetermined product water criteria include that the pressure of the product water within the product water path remains below a predetermined upper pressure level.

[0041] According to some embodiments, the method includes measuring the water temperature within the purified water path downstream of a heater disposed within the purified water path. According to these embodiments, the adjustment then includes adjusting the flow rate of the water within the recirculation path such that the temperature of the water flowing through the RO membrane of the RO device meets a predetermined temperature criterion based on the temperature detected by the temperature sensor.

[0042] Thereby, the temperature range of the water entering the RO membrane will be less dependent on the incoming water temperature and the ambient temperature since the return flow rate of the heated purified water is available and can increase the water temperature within the tank. As a result, the filtration behavior of the membrane will be more stable.

[0043] According to some embodiments, the method includes continuously performing the detection and adjustment while the water purification device is producing purified water.

[0044] According to some embodiments, the method includes activating an alarm function in response to a change in at least one detected product fluid characteristic. Thus, the proposed method according to these embodiments also enables the water purifier to detect sudden changes in pressure such as a filter breakage that means a lower pressure drop, thereby a lower pressure and an increased flow rate in the product water path. Alternatively, if a leak occurs between the water purifier and the filter, it results in a pressure drop and the alarm sounds.

[0045] According to some embodiments, the predetermined upper pressure level corresponds to the pressure tolerance level of at least one filter arranged to filter product water downstream of the product water path or any other component arranged within the product water path or within a predetermined distance from the purified water path.

[0046] According to some embodiments, the control includes controlling the fluid characteristics of the product water to obtain a predetermined flow rate during a predetermined time period to produce a predetermined amount of water. Further, the water purifier may continue to send the required amount to the dialysis device even if communication with the dialysis device is lost. The predetermined amount is typically 0.5 to 400 liters.

[0047] According to some embodiments, the method includes controlling the temperature of the product water flowing within the product water path.

[0048] According to some embodiments, a polisher is arranged downstream of the recirculation circuit in the purified water stream, and then the product water path is arranged to convey the product water from the outlet of the polisher to the product water port.

[0049] According to a third aspect, the disclosure relates to a computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the methods described above and below.

[0050] According to a fourth aspect, the disclosure relates to a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to perform the methods described above and below.

Brief Description of the Drawings

[0051] Embodiments of the present invention will be described in more detail with reference to the accompanying drawings which illustrate examples of embodiments of the present invention shown below.

Figure 1

Figure 2

Figure 3

Figure 4a

Figure 4b

Figure 5

Figure 6

DETAILED DESCRIPTION OF THE INVENTION

[0052] For example, when using a water purification device such as a point-of-care, it would be desirable to be able to control the flow rate of purified water, i.e., product water. If the flow rate of the product water is constant or at least known, the amount of water produced during a certain production time can be predicted.

[0053] Generally, it is desirable to produce the desired amount of product water as quickly as possible. However, if the product water flow rate is too high, the water pressure in the water purification device may be too high, which may damage the fluid system and other hardware within or related to the water purification device. Furthermore, if the product water flow rate or pressure is too high, for example, the filter in a dedicated line set arranged to supply product water to a dialysis device may be damaged, which may cause a risk of bacteria and endotoxins reaching the patient.

[0054] Accordingly, the proposed method proposes a method for controlling the product water flow rate from a water purification device based on one or more product water fluid characteristics or parameters such as the flow rate, pressure, or temperature of the product water in the product water path. The control is implemented, for example, using an electrically controlled proportional valve in the recirculation path of the water purification device. The electrically controllable valve can also be used to control other fluid characteristics of the purified water such as pressure or temperature.

[0055] To better understand the proposed method, a water purification device capable of implementing the proposed method will be described below as part of a peritoneal dialysis system. However, the proposed technology can also be implemented in other types of dialysis systems, for example, in a water purification device used to produce purified water in a hemodialysis or CRRT system, for use in the production of dialysis fluid used in hemodialysis, or for use in a CRRT treatment implemented by the system at the point of care or at the time of use.

[0056] Reference is now made to the drawings, and in particular to FIG. 1, which illustrates a peritoneal dialysis system having a point of use for dialysate production by system 10a. System 10a includes a cycler 20 and a water purification device 300. Cyclers suitable for cycler 20 include, for example, the Amia® or HomeChoice® cyclers commercially available from Baxter International Inc., and it is understood that those cyclers require updated programming to perform and use the point of use of the dialysate produced according to system 10a. For this purpose, cycler 20 includes a control unit 22 having at least one processor and at least one memory. Control unit 22 further includes a wired or wireless transceiver for transmitting and receiving information to and from water purification device 300. Water purification device 300 also includes a control unit 112 having at least one processor and at least one memory. Control unit 112 further includes a wired or wireless transceiver for transmitting and receiving information to and from control unit 22 of cycler 20. Wired communication may be via, for example, an Ethernet connection. Wireless communication can be performed via any of Bluetooth®, WiFi™, Zigbee®, Z-Wave®, wireless Universal Serial Bus (“USBus”), or infrared protocol, or via other suitable wireless communication technologies. Control unit 22 includes a computer program including instructions that, when executed by control unit 22, cause control unit 22 and the water purification device to execute any one or more of the methods and programs according to any one of the embodiments disclosed herein. These instructions can be stored on a portable memory device, such as a USB memory, a portable computer, or a similar computer-readable medium, and loaded into control unit 22.

[0057] The cycler 20 includes a housing 24 that holds a device programmed via a control unit 22 to prepare fresh dialysate at the time of use, deliver the freshly prepared dialysate to patient P, allow the dialysate to dwell within patient P, and then deliver the used dialysate to drain. In FIG. 1, the water purification device 300 includes a first drain path 384 that leads to a drain 339 which can be a housing drain or a drain container. The device programmed via the control unit 22 to prepare fresh dialysate at the time of use includes (i) one or more positive pressure reservoirs, (ii) one or more negative pressure reservoirs, (iii) a compressor and a vacuum pump under the control of the control unit 22 for providing positive and negative pressures to be stored in the one or more positive and negative pressure reservoirs, or a single pump that creates both positive and negative pressures under the control of the control unit 22, (iv) a plurality of pneumatic valve chambers for sending positive and negative pressures to a plurality of fluid valve chambers, (v) a plurality of pneumatic pump chambers for sending positive and negative pressures to a plurality of fluid pump chambers, (vi) a plurality of electrically actuated solenoid pneumatic valves under the control of the control unit 22 and positioned between the plurality of pneumatic valve chambers and the plurality of fluid valve chambers, (vii) a plurality of electrically actuated variable pneumatic valves under the control of the control unit 22 and positioned between the plurality of pneumatic pump chambers, (viii) in one embodiment a heater under the control of the control unit 22 for heating the dialysate as it is being mixed, and (viii) an occluder 26 under the control of the control unit 22 for closing off the patient and the drain line in the event of an alarm and other situations, but is not limited thereto..

[0058] In one embodiment, the plurality of pneumatic valve chambers and the plurality of pneumatic pump chambers are located on the front or surface of the housing 24 of the cycler 20. The heater is located within the housing 24 and in some embodiments includes a heating coil that contacts a heating pan located at the top of the housing 24 under a heating lid (not seen in FIG. 1).

[0059] The cycler 20 of FIG. 1 also includes a user interface 30. The control unit 22 of one embodiment includes a video controller, which may have its own processing and memory for interacting with the main control processing and memory of the control unit 22. The user interface 30 includes a video monitor 32, which can operate with a touch screen overlay placed on the video monitor 32 to input commands to the control unit 22 via the user interface 30. The user interface 30 can also include one or more electromechanical input devices such as membrane switches or other buttons.

[0060] The water purification device 300 of FIG. 4 also includes a user interface 120. Next, the control unit 112 of the water purification device 300 can include a video controller, which can have its own processing and memory for interacting with the main control processing and memory of the control unit 112. The user interface 120 includes a video monitor 122, which can also operate with a touch screen overlay placed on the video monitor 122 to input commands to the control unit 112. The user interface 120 can also include one or more electromechanical input devices such as membrane switches or other buttons. The control unit 112 can further include an audio control unit for playing audio files such as alarms or alert sounds in one or more speakers 124 of the water purification device 300.

[0061] With additional reference to FIG. 2, a disposable set 40 is shown. The disposable set 40 is also shown in FIG. 1 and is coupled to the cycler 20 to move liquid within the disposable set 40 and mix dialysate, for example, as discussed herein. The disposable set 40 in the illustrated embodiment includes a disposable cassette 42, which may include a planar rigid plastic piece covered on one or both sides by a flexible membrane. The membrane crimped to the housing 24 of the cycler 20 forms pump and valve membranes. FIG. 2 shows that the disposable cassette 42 includes a fluid pump chamber 44 that operates with a pneumatic pump chamber located in the housing 24 of the cycler 20 and a fluid valve chamber 46 that operates with a pneumatic valve chamber located in the housing 24 of the cycler 20.

[0062] FIGS. 1 and 2 show that the disposable set 40 includes a patient line 50 that extends from a patient line port of the cassette 42 and terminates at a patient line connector 52. FIG. 1 shows that the patient line connector 52 connects to a patient transfer set 54, which in turn connects to a dwell catheter located within the peritoneal cavity of patient P. The disposable set 40 includes a drain line 56 that extends from a drain line port of the cassette 42 and terminates at a drain line connector 58. FIG. 1 shows that the drain line connector 58 is removably connected to a drain port 118 of the water purification device 300 to receive used dialysate from the cycler 20.

[0063] Figures 1 and 2 further illustrate that the disposable set 40 includes a heater / mixing line 60 that extends from the heater / mixing line port of the cassette 42 and terminates at a heater / mixing bag 62, which will be described later. The disposable set 40 includes an upstream water line segment 64a that extends to the water inlet of the water accumulator 66 for water. The downstream water line segment 64b extends from the water outlet 66b of the water accumulator 66 for water to the cassette 42. In the illustrated embodiment, the upstream water line segment 64a begins at the water line connector 68 and is located upstream from the water accumulator 66 for water. FIG. 1 shows that the water line connector 68 is removably connected to the product water port 128 of the water purifier 110.

[0064] The water purification device 300 outputs purified water and water suitable for, for example, peritoneal dialysis ("WFPD"). WFPD is water suitable for making dialysate to be delivered to the abdominal cavity of the patient P, and is, for example, dialysis water or water for injection.

[0065] In one embodiment, the sterilization grade filter 70a is disposed upstream from the downstream sterilization grade filter 70b. Filters 70a and 70b can be disposed in the water line segment 64a upstream of the water accumulator 66 for water. The sterilized sterilization grade filters 70a and 70b may be through filters without a waste line. The pore size of the sterilization filter may be less than one micron, such as 0.1 or 0.2 micron, for example. Suitable sterilization grade filters 70a and 70b may be, for example, Pall IV-5 or GVS Speedflow filters, or filters provided by the person in charge of the present disclosure. In an alternative embodiment, only one or more than two sterilization grade filters are disposed in the water line segment 64a upstream of the water accumulator 66. One or more sterilization grade filters can be disposed near the water accumulator 66 so that the disposable set 40 is easily foldable. In a further alternative embodiment, there is no sterilization grade filter in the water line segment 64a. The sterile sterilization grade filter can be replaced, for example, by one or several ultrafiltration filters located in the product water path of the water purification device 300.

[0066] FIG. 2 further shows that the last bag or sample line 72 may be provided to extend from the last bag or sample port of the cassette 42. The last bag or sample line 72 terminates at a connector 74 that can be connected to the combined connector of the last filling bag of the pre-mixed dialysate, or a sample bag or other sample collection container. The last bag or sample line 72 and the connector 74 may alternatively be used for a third type of concentrate, if desired.

[0067] FIGS. 1 and 2 show that the disposable set 40 includes a first concentrate line 76 that extends from the first concentrate port of the cassette 42 and terminates at the first cassette concentrate connector 80a. The second concentrate line 78 extends from the second concentrate port of the cassette 42 and terminates at the second cassette concentrate connector 82a.

[0068] Figure 1 shows that the first concentration container 84a holds the first, for example, glucose concentrate, which is sent from the container 84a through the container line 86 to the first container concentration connector 80b, which is coupled to the first cassette concentration connector 80a. The second concentration container 84b holds the second, for example, buffer solution, concentrate, which is sent from the container 84b through the container line 88 to the second container concentration connector 82b and connected to the second cassette concentration connector 82a.

[0069] To initiate treatment, the patient P typically loads the cassette 42 into the cycler and, in a random or specified order, (i) places the heater / mixing bag 62 on the cycler 20, (ii) connects the upstream water line segment to the product water port of the water purification device 300, (iii) connects the drain line 56 of the water purification device 300 to the drain port 118, (iv) connects the first cassette concentration connector 80a to the first container concentration connector 80a, and (v) connects the second cassette concentration connector 82a to the second container concentration connector 82b. At this point, the patient connector 52 is still capped. When fresh dialysate is prepared and verified, the patient line 50 is primed with fresh dialysate, after which the patient P can connect the patient line connector 52 to the treatment transfer set 54. Each of the above steps may be graphically illustrated on the video monitor 32 and / or provided via voice guidance from the speaker 34.

[0070] Here, the water purification device 300 will be described in more detail.

[0071] Figure 3 is a schematic diagram of the functional parts of the water purification device 300, including a pretreatment module 160, a reverse osmosis (RO) module 170, and a post-treatment module 180. The water purification device 300 includes an inlet 399 for supplying water from a water source 398, for example, tap water, to the water purification device 300 for water purification. The incoming water from the water source is supplied to the pretreatment module 160 through the inlet 399.

[0072] Pretreatment module The pretreatment module 160 treats the incoming water with a particle filter and a bed of activated carbon.

[0073] The particle filter is arranged to remove particles such as clay, sediment, and silicon from the incoming water. The particle filter is arranged to prohibit particles of micrometer size, optionally also larger endotoxin molecules, from entering the incoming water.

[0074] The bed of activated carbon is arranged to remove chlorine and chlorine-containing compositions from the incoming water and to absorb toxic substances and pesticides. In one embodiment, the bed of activated carbon is arranged to remove one or more of hypochlorite, chloramine, and chlorine. In a further embodiment, the bed of activated carbon is also arranged to reduce the organic compounds (total organic carbon, TOC) containing pesticides in the incoming water.

[0075] In some embodiments, the particle filter and the bed of activated carbon are integrated into a single consumable. For example, the consumable is replaced at predetermined intervals depending on the incoming water quality. For example, the quality of the incoming water is inspected and determined by a qualified person before the water purification device 300 is first used at the time of care.

[0076] Optionally, the pretreatment module 160 comprises an ion exchange device for protecting devices placed downstream, such as a reverse osmosis (RO) membrane and a polishing agent.

[0077] Thus, the pretreatment unit 160 filters the incoming water and supplies the pretreated water to the RO unit 170 located downstream.

[0078] RO module The RO module 170 removes impurities such as microorganisms, pyrogens, and ionic substances from the pretreated water that has been filtered by reverse osmosis. The pretreated water is pressurized by a pump and forced through the RO membrane to overcome the osmotic pressure. The RO membrane is, for example, a semipermeable membrane. As a result, the flow of the pretreated water, called the feed water, is divided into a drain flow and a permeate flow. In one embodiment, the waste water can be passed through one or both of the first waste path and the second waste path. The first waste path discards the water that returns to the feed water path of the RO pump for being fed back to the RO device again. The recycled waste water increases the supply flow to the RO-device and obtains a sufficient flow rate to pass through the waste side of the RO-membrane to minimize scaling and fouling of the RO-membrane. The second waste path leads to discard the drain. Thereby, the concentration level on the waste side becomes low enough to obtain the appropriate and required permeate concentration. When the supply water has a low solute content, a part of the drain flow can also be refluxed to the inlet side of the RO membrane, thereby increasing the water efficiency of the water purification device 300.

[0079] In this way, the RO section 170 treats the pretreated water and sends the permeate water downstream to the post-treatment module 180.

[0080] Post-treatment module The post-treatment module 180 polishes the permeate water in order to further remove ions from the permeate water. The permeate water is polished using a polisher such as an electro-deionization (EDI) device or a mixed bed filter device.

[0081] The EDI device utilizes electro-deionization to remove ions from the permeated water such as aluminum, lead, cadmium, chromium, sodium and / or potassium that have permeated through the RO membrane. The EDI device uses electricity, ion exchange membranes and resins to deionize the permeated water and separate the dissolved ions, i.e., impurities, from the permeated water. The EDI device produces polished water, and the EDI device polishes it to a purity level higher than the purity level of the permeated water. The EDI device has an antibacterial effect on the product water, and in particular, the amount of bacteria and endotoxins in the water can be reduced by the electric field in the EDI device. In one embodiment, the EDI device has a capacity to produce 70 - 210 ml / min of product water. Therefore, the capacity of the EDI device sets the limit of the flow rate of the produced water.

[0082] The mixed bed filter device includes a column or container having a mixed bed ion exchange material.

[0083] In this specification, the polished water, also referred to as product water, is then ready to be delivered from the product water port 128 of the water purification device 300 to the point of use of the product water. The product water is suitable for dialysis, i.e., dialysis water. In one embodiment, the product water is water for injection. In one embodiment, a disposable set 40 including a water line 56 is disposed in the water purification device 300 for transporting the product water to the point of use. Optionally, the water purification device 300 is provided with a drain port 118. In one exemplary embodiment, the drain port 118 is used to receive liquid, for example, from a PD patient via a drain line 64, for further conveyance to the drain 339 of the water purification device 300 via a first drain path 384 within the water purification device 300. As a further option, the drain port 118 receives a sample of the prepared mixed solution for further conveyance to a conductivity sensor disposed, for example, in the first drain path 384 within the water purification device 300. The disposable set 40 has sterilized sterilization filters 70a, 70b disposed therein for filtering the product water from the water purification device 300 and ensuring the quality of the product water as water for injection.

[0084] In this way, the product water collected in the storage bag 66 passed through one or more sterilization grade filters of the disposable set 40 in order to remove bacteria and endotoxins, that is, to produce sterile product water. According to one embodiment, the sterilization grade filter is redundant.

[0085] By collecting sterile product water in the storage bag 66, the water purification device 300 and the cycler 20 are separated with respect to pressure, so that as a result, the high pressure required to push water through the sterile sterilization grade filter does not affect the cycler 20.

[0086] The control unit 112 of the water purification device 300 is arranged to set the water purification device 300 to different operating states, such as standby, connection, idle, operation, and maintenance. The water purification device 300 is arranged to act on commands from the cycler 20.

[0087] When not in use but powered on, the water purification device 300 is set to the standby state.

[0088] In standby, the water purification device 300 waits for a connection or maintenance command.

[0089] The main steps of different states are described. For example, steps performed for risk reduction, such as comparison of flow sensors, tests such as no leakage in the flow path, are omitted.

[0090] Connection state During the connection state, the system tests the sensors, checks the EDI device, and confirms that the system is ready when a command to proceed to the idle state is received. The connection state can include, for example, flushing of certain components within the pre-treatment section 160.

[0091] The patient is also generally required to take a sample of the incoming water at a sampling port located after the pretreatment module 160. What is being checked in this sample is that the levels of chlorite, chloramine, and chlorine-containing chlorine are below the acceptable levels.

[0092] When all steps of the connection state are executed, the system is ready.

[0093] Idle state In this state, the water purification device 300 is waiting for either a return fluid conductivity measurement (when testing newly prepared dialysis fluid) or a new supply product water request from the cycler 20.

[0094] In this state, the water purification device 300 can prepare itself to deliver product water. Then, instead of sending the product water out from the product port 128, the water purification device 300 recirculates the product water to the tank 350 until the product water obtains a stable conductivity level, and the RO device operates at the desired operating point for the RO device 301.

[0095] The water purification device 300 occasionally recirculates the water path to minimize the startup time of the water production stage.

[0096] The idle state can also include, for example, flushing certain components within the pretreatment module 160.

[0097] Operating state In the operating state, the water purification device 300 supplies product water (e.g., the volume required by the cycler 20) to the accumulation bag 66 of the disposable set.

[0098] The proposed technology will be described in more detail with reference to FIGS. 4a, 4b, and 5.

[0099] Figure 4a shows a water purification device 300 including an RO device 301. It should be noted that Figure 4a is only a conceptual diagram and illustrates only the parts related to the proposed technology of the water purification device 300. In connection with Figure 6, a more detailed illustration of an exemplary water purification device 300 and its operation is provided.

[0100] The water purification device 300 in Figure 4a consists of an RO device 301, a tank 350, an RO pump 450, a water supply path 390, a recirculation path 375, a purified water path 371, a control device 305a, a temperature sensor 303, a pressure sensor 308, a flow sensor 309, a heater 302, a flow sensor 380, a product water port 128, and a control unit 112.

[0101] The RO device 301 is arranged to produce a purified water stream and a waste stream. More specifically, the RO device 301 includes an RO membrane 324, a supply port 301a, a purified water outlet 301b, and a waste outlet 301c. The RO membrane 324 separates the supply port 301a and the waste outlet 301c from the purified water outlet 301b. The waste stream is directed into the first waste path 385b and / or the drain 339 of the water purification device 300. The first waste path 385b is fluidly connected to the waste outlet 301c and the water supply path 390.

[0102] The water supply path 390 is arranged to convey supply water to the supply port 301a. The water supply path 390 is fluidly connected to the supply port 301a.

[0103] The tank 350 is arranged in the water supply path 390 for collecting water. More specifically, the tank 350 is arranged to receive water from an external water source and supply water to the supply port 301a. According to some embodiments, the tank 350 is optional, which is indicated by the dashed line in Figure 4a.

[0104] The RO pump 450 is disposed within the water supply path 390 and delivers the water supply to the supply port 301a. The RO pump 450 is disposed downstream of the tank 350 (if present). The RO pump 450 is configured to be controlled to a constant pump speed corresponding to a constant flow rate of the permeate water flow. Since the permeability of the RO membrane 324 increases as the temperature of the supply water rises, the relationship between the pump speed and the flow rate depends on the temperature of the water supplied to the supply port 301a and thus the temperature of the RO membrane 324.

[0105] The product water port 128 is arranged to supply product water to, for example, a dialysis device via a dedicated line set. A sterilization grade filter (not shown) is typically located downstream of the product water port 128 on a line set outside the water purification device 300.

[0106] The recirculation path 375 is arranged to recirculate a portion of the purified water flow from a first point downstream of the RO device 301 to a second point upstream of the RO device 301. More specifically, the recirculation path 375 is arranged to circulate the heated purified water from a point downstream of the RO device 301 to the water supply path 390 inside the water purification device 300. In the example of FIG. 4a, the purified water is recirculated to the tank 350 and supplied again to the supply port 301a of the RO device 301. However, the purified water may be directly recirculated to the water pipe upstream of the RO pump 450.

[0107] The purified water path 371 is fluidly connected to the purified water outlet 301b and the product water outlet 128. The purified water path 371 is configured to convey purified water from the purified water outlet 301b to the product water outlet 128. The purified water path 371 includes a permeate water path 371a and a product water path 371c. Here, the product water path refers to a part of the purified water path 371 closest to the product water outlet 128, where the fluid characteristics such as pressure and flow rate are the same (or similar) as those of the product water outlet 128.

[0108] The heater 302 is arranged to heat the product water flowing within the product water path 371c. The heater 302 is, for example, a heater arranged to heat the purified water produced by the RO device 301. Further, in the embodiment of FIG. 4a, the purified water leaving the RO device 301 also passes through the flow sensor 410 and the temperature sensor 303 included in the permeate water path 371a.

[0109] The purified water path 371 includes a polisher 306, for example, an electro-deionization (EDI) device. Alternatively, the polisher 306 is a mixed bed filter device. The polisher 306 is arranged downstream of the recirculation circuit 374 within the purified water path 371. Thus, the polisher 306 is arranged in the purified water path 371 downstream of the point where the recirculation path 375 is connected to the purified water path. The polisher 306 is fluidly connected to the permeate water path 371a and the product water path 371c. In other words, according to some embodiments, the permeate water path 371a is arranged to convey purified water from the purified water outlet 301b of the RO device 301 to the inlet of the polisher 306, and the product water path 371c is arranged to convey purified water from the outlet of the polisher 306 to the product water outlet 128.

[0110] This disclosure is based on the insight that fluid characteristics such as the pressure or flow rate of product water within the product water path 371c can be controlled by controlling the portion of the permeate flow produced by an RO device that is recirculated to the supply port 301a. To enable such control, a control device 305a, such as an electrically controllable valve, is arranged. In other words, the control device 305a is arranged to regulate the flow rate of purified water within the recirculation path 375. According to some embodiments, the control device 305a is configured to receive control data and regulate the proportion of the permeate flow that is recirculated based on the control data. The control data may be an electrical signal (analog or digital). The control device 305a is typically a flow control device such as a proportional valve. A proportional valve is typically electrically controlled. However, a mechanical proportional valve can also be used. In one embodiment, the control device 305a is a pump, for example, a positive displacement pump such as a volumetric pump or a piston pump.

[0111] As described above, the proposed approach enables the control of at least one fluid characteristic, such as the flow rate or pressure within the product water path 371c, when operating a water purification device. According to some embodiments, the proposed technique enables the control of other characteristics, such as the temperature of the RO membrane 324 or the operating point of the RO device, for example, permeate fluid characteristics. To enable such control, it is necessary to measure the relevant fluid characteristic(s) or at least detect or estimate them in some way. Accordingly, at least one detector is arranged to detect the fluid characteristics of the purified water within the purified water path 371.

[0112] According to some embodiments, at least one detector is arranged to detect the product fluid characteristics of the product water within the product water path 371c. The at least one detector can be implemented in a plurality of ways. According to some embodiments, the at least one detector is configured to provide product fluid characteristic data that defines at least one product fluid characteristic. According to some embodiments, the control is based on permeate fluid characteristics, such as other characteristics such as the temperature of the purified water flow within the permeate water path 371a.

[0113] In FIG. 4a, at least one detector is the flow rate sensor 309 and the pressure sensor 308. And the product fluid property measured by the flow rate sensor 309 is the flow rate of the product water in the product water path 371c. The product fluid property detected by the pressure sensor 308 is the pressure in the product water path 371c. Further, the temperature sensor 303 is arranged to measure the temperature of the purified water in the permeate water path 371a downstream of the heater 302.

[0114] The control unit 112 typically includes one or more microprocessors 1122 and / or one or more circuits such as application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), etc.

[0115] The control unit 112 may also include at least one memory 1123 such as a non - transient storage medium (e.g., hard drive, flash memory, optical disk, etc.) and / or a volatile storage device (e.g., dynamic random access memory (DRAM), etc.).

[0116] The control unit 112 further comprises an interface 1121 configured to enable communication with other components of the water purification device 300 (e.g., sending control data and receiving sensor data), in particular enabling communication with the control device 305a and at least one detector, such as the pressure sensor 308 and / or the flow rate sensor 309.

[0117] The control unit 112 is configured to have the functions of the water purification device 300. In particular, the control unit 112 includes the methods described in connection with FIG. 6 and is configured to implement all embodiments of the proposed technology described herein. To achieve this, the control unit 112 is configured to receive fluid characteristic data from at least one detector and transmit control data to the control device 305a. More specifically, the control unit 112 controls the control device 305a to adjust the flow rate of the purified water in the recirculation path 375 so as to meet one or more predetermined criteria of the purified water in the purified water path 371, for example, based on the fluid characteristics detected by at least one detector. The fluid characteristics are measured, for example, by any sensor in the purified water path 371.

[0118] According to some embodiments, the control unit 112 is configured to control the control device 305a to control the product fluid characteristics of the product water in the product water path 371c so as to meet one or more predetermined product water criteria based on the fluid characteristics detected by at least one detector, such as the pressure sensor 308 and / or the flow rate sensor 309. In other words, the control unit 112 is configured to control the flow rate of the water in the recirculation path 375 to meet one or more criteria, such as obtaining a certain fluid characteristic, for example, a certain pressure or flow rate, in the product water flow.

[0119] As described above, different product fluid characteristics can be controlled. Therefore, the determination criteria for the product water may include one or more regulatory conditions. Here are some examples. It should be understood that these can be used alone or in combination. In the simplest form, at least one determination criterion for the product water includes only one condition.

[0120] In the first example, the goal of control is to achieve a constant product water flow rate. The control criterion will then attempt to maintain a constant product water flow rate through the product water port 128. The flow rate through the product water port 128 is typically the same (or at least approximately the same) as the entire product water path 371c. Thus, according to some embodiments, the predetermined criterion includes that the flow rate of the product water in the product water path 371c corresponds to a predetermined flow rate, such as 150 ml / min or 250 ml / min. If a constant flow rate of product water can be obtained, it is easy to estimate how much time it takes to produce a certain amount of product water.

[0121] For example, the water purification device 300 can be controlled to produce product water having a constant product water flow rate during a predetermined time period. In other words, according to some embodiments, the control circuit is configured to control the control device 305a to obtain a predetermined flow rate through the product water port 128 during a predetermined time period in order to produce a predetermined amount of water. The predetermined amount is, for example, 0.5 to 400 liters. The predetermined amount can correspond to the amount required for one or several dialysis treatments. For example, the water purification device 300 can be controlled to produce 0.5, 1, 2, 5, 10, 20, 50, 70, 90, 150, 200, 250, 300 or 400 liters of purified water.

[0122] In the second example, the goal of control is to achieve a limited or controlled product water pressure. The pressure of the product water in the product water path 371c typically should not exceed the maximum allowable level. The maximum allowable level is, for example, to ensure that the hardware such as the filter inside or associated with the water purification device or polisher 306 is not damaged. In other words, according to some embodiments, the predetermined upper pressure level corresponds to the pressure tolerance level of at least one filter (e.g., a sterilization grade filter) or any other component arranged in the product water path 371c. Thus, according to some embodiments, the predetermined criterion includes that the pressure of the product water in the product water path 371c remains below the predetermined upper pressure level.

[0123] Typical implementations of the specified criteria can include, for example, controlling the control device 305a to attempt to obtain a predetermined flow rate of product water in the product water path 371c as long as the pressure of the product water in the product water path 371c remains below a predetermined upper pressure level. When the pressure reaches the predetermined upper pressure level, the control device 305a instead controls the control device to maintain the pressure at that level even if the flow rate of the product water in the product water path falls below the predetermined flow rate.

[0124] As described above, the processing capacity for a given product water pressure will decrease over time. By controlling how much of the permeate is recirculated within the recirculation path 375, the product water pressure can be continuously increased to compensate for such behavior. In other words, according to some embodiments, a given product water criterion includes the pressure of the product water in the product water path 371c corresponding to a pressure level. The pressure level in the product water path 371c can correspond, for example, to the expected processing capacity through the product water port 128 and thus can change (typically increase) over time.

[0125] In a third example, the goal of control is, for example, to maintain a constant operating point of one or more hardware components within the water purification device 300, such as the RO device 301 (which is considered to be at least partially included in the permeate path 371a) or the polisher 306, within the permeate path 371a or the polisher water path 371b (FIG. 6). The operating point is, for example, a constant pressure, a constant flow rate, or a constant temperature. Next, an operating point criterion is typically formulated to keep the operating point within a certain interval.

[0126] For example, the flow rate or water pressure in the permeate path 371a directly downstream of the RO device 306 is measured (or estimated) using the flow rate sensor 410. In principle, any detector in either the permeate path 371a or the polisher water path 371b may be used.

[0127] Next, the permeate fluid characteristics such as the pressure in the RO device (particularly the transmembrane pressure of the RO membrane) or the flow rate passing through the polisher 306 can be controlled using the control device 305a.

[0128] In other words, according to some embodiments, the control unit 112 controls the control device 305a to control the permeate fluid characteristics of the permeate water in the permeate water path 371a (for example, to meet the operating point criteria of the RO membrane 324 or the polisher 306) based on the permeate fluid characteristics detected by at least one detector, such as the temperature sensor 302 or the flow rate sensor 410, so as to meet one or more predetermined permeate water criteria.

[0129] In a fourth example, the goal is to keep the operating temperature of the RO membrane 324 of the water purification device 300 at a constant temperature, for example, independent of the temperature of the influent water supplied through the inlet 399 (FIG. 3) or the ambient temperature. Since the operating characteristics such as the processing capacity and purification characteristics of the RO membrane 324 typically depend on the temperature of the RO membrane 324, constant temperature is generally desirable. By keeping the temperature of the water passing through the RO membrane 324 constant, a constant operating temperature of the RO membrane can be achieved. The temperature of the water passing through the RO membrane 324 is (at least basically) the same as the temperature of the purified water in the permeate water path 371a directly downstream of the RO device 301, that is, upstream of the heater 302. This temperature depends on several factors such as the temperature of the inlet water supplied to the inlet port 399 (FIG. 3), the proportion of the heated water recirculated in the recirculation path 375, and the temperature of the recirculated water, that is, the temperature of the purified water after the heater.

[0130] The relationship between the temperature of the purified water before the heater 302 and the temperature of the purified water after the heater 302 can be calculated using thermodynamics and the following equation.

[0131]

Equation

[0132] In the formula, P is the output (in watts) of the heater 302, Q is the flow rate [l / s] passing through the heater 302 (which is the same as the flow rate passing through the RO membrane 324), T2 is the temperature of the purified water downstream of the heater 302, and T_RO is the temperature upstream of the heater 302 (i.e., the temperature of the water passing through the RO membrane 324). Therefore, ΔT is the temperature difference between the water upstream of the heater 302 and the water downstream of the heater 302, i.e., ΔT = T2 - T_RO. Further, cp is the specific heat capacity of water. Specific heat capacity or heat capacity is a measurable physical quantity and is equal to the ratio of the heat added to (or removed from) an object that causes a temperature change. The specific heat capacity of water is 4.19 kJ / K. For example, when the flow rate Q passing through the RO membrane 324 is 210 ml / min (i.e., 0.0035 l / s), the temperature of the purified water T2 in the permeate water path is 85°C, and the heating output P is 200 W, the temperature obtained by the RO membrane is estimated as follows.

[0133] [Number]

[0134] The temperature T2 of the purified water in the permeate water path 371a may be measured using the temperature sensor 303. Thus, since the output P of the heater 302 and the flow rate Q passing through the RO membrane 324 are known, the temperature of the RO membrane 324, or rather the temperature of the water passing through the RO membrane 324, can be estimated from the measured temperature T2 of the purified water in the permeate water path.

[0135] For example, if a change in the temperature T2 of the purified water in the permeate water path 371a is detected while the output of the heater 302 and the flow rate Q passing through the heater are kept constant, it indicates that the temperature of the feed water passing through the RO membrane 324 has changed due to, for example, a change in the temperature of the influent water or a change in the ambient temperature.

[0136] One way to achieve the goal of maintaining a constant is, next, to adjust the output P supplied by the heater (i.e., to control the temperature of the recirculating water), or to vary the flow rate Q through the heater 302 in response to a measured change in the temperature T2 of the purified water in the permeate path 371a. The flow rate Q of the water flowing through the heater 302 (and the RO membrane 324) can be controlled by varying the pump frequency of the RO pump 450. However, in some embodiments, it is desirable to use one pump frequency for each batch of water.

[0137] Another way to achieve the goal of maintaining T_RO constant is to vary the amount of heated water recirculated in the recirculation path 375. For example, if more heated water is recirculated, the temperature of the water in the tank 350 will rise. This will then raise the temperature of the feed water supplied through the feed port 301a, and as a result, the temperature T_RO of the water passing through the RO membrane 324 will also rise.

[0138] From the above, the temperature T_RO of the water passing through the RO membrane 324 can be estimated from the measured temperature T2 of the purified water in the permeate path 371a using Equation 1. Then, by controlling the control device 305a to adjust the ratio of the permeate flow recirculated in the recirculation path, the temperature T_RO of the water passing through the RO membrane 324 can be kept constant. For example, the ratio of the permeate flow recirculated in the recirculation path may be continuously adjusted so that the estimated temperature T_RO of the water passing through the RO membrane 324 is kept constant.

[0139] In other words, according to some embodiments, the control unit 112 is configured to control the control device 305a to control the temperature T_RO of the water flowing through the RO membrane 324 based on the temperature detected by the temperature sensor 303. Typically, the control unit 112 is configured to control the control device 305a to control the temperature T_RO so that a predetermined temperature criterion is met. The criterion includes, for example, that the temperature T_RO of the water flowing through the RO membrane 324 is maintained within a predetermined interval.

[0140] Thus, the control device 305a can be controlled to keep the temperature of the water after the RO membrane 324 within a predetermined temperature or within a predetermined temperature range.

[0141] The third and fourth embodiments can be used in combination with the above-described embodiments and can correspond to the criteria of the product water intended to control the product fluid characteristics of the product water in the product water path 371c. Next, for optimal control, it is necessary to combine different criteria regarding pressure, flow rate, and temperature (for example, prioritization and weighting).

[0142] In an alternative embodiment, these (third and fourth) embodiments are independent of the above-described embodiments. Then, the control unit 112 is not configured to control the control device 305a to control the product fluid characteristics of the product water in the product water path 371c to meet one or more predetermined product water criteria (at least not simultaneously). Instead, based on the temperature detected by the temperature sensor 303, for example, only the control device 305a may be configured to control the temperature of the water flowing through the RO membrane 324.

[0143] According to some embodiments, the control unit is configured to activate an alarm function in response to a change in at least one product fluid characteristic detected by at least one detector, such as the pressure sensor 308 and / or the flow rate sensor 309. For example, in order to minimize the risk of exceeding a predetermined upper pressure level, the control unit 112 may be configured to trigger an alarm when the pressure measured by the pressure sensor exceeds the predetermined upper pressure level.

[0144] The alarm is triggered in response to a significant or sudden pressure drop or the like, which will serve as an indicator of a malfunction. For example, breakthrough in a filter such as a sterilization-grade filter can cause a pressure drop, thereby potentially causing a pressure drop and an increase in flow rate of the product water in the product water path 371c. Since these events are inconsistent, the control unit 112 may be likely to issue an alarm in such a situation.

[0145] In another example, a leak from the system between the water purification device 300 and the sterilization-grade filters 70a, 70b will result in a decrease in the pressure of the product water in the product water path 371c. The leak would also be a severe error that should trigger an alarm.

[0146] In other words, according to some embodiments, the control unit 112 is configured to activate an alarm function in response to a pressure change measured by the pressure sensor 308 and / or a flow rate change measured by the flow rate sensor 309.

[0147] FIG. 4b shows the functions of the control unit 112 of the water purification device 300 according to an embodiment. In this example, the control unit includes a cascade control arrangement including a flow rate controller 112a and a pressure controller 112b. In a cascade control arrangement, there are two (or more) controllers, and the output of one of the controllers drives the setpoint of another controller.

[0148] In this example, the flow rate controller 112a drives the setpoint of the pressure controller 112b to obtain a predetermined flow rate of the product water in the product water path 371c. In other words, the flow rate controller 112a compares the flow rate of the product water in the product water path 371c measured by the flow rate sensor 309 with a reference flow rate f ref , for example, 200 ml / min, and generates first control data d 1 for the pressure controller 112b.

[0149] The pressure controller 112b sequentially drives the control device 305a so that the flow rate matches the setpoint required by the flow rate controller 112a as long as the pressure does not exceed a predetermined pressure level, for example, 300 kPa. In other words, the pressure controller 112b compares the pressure of the product water in the product water path 301c measured by the pressure sensor 308 with the first control data d 1 and generates second control data d 2 . Next, the pressure controller 112b controls the control device 305a using the second control data d 2 .

[0150] A controller (flow controller 112a in the above example) that drives a setpoint is called a primary, outer, or master controller. A controller that receives a setpoint (pressure controller 112b in the example) is called a secondary, inner, or slave controller. The control loop frequency of the inner loop can typically be higher than that of the outer loop. For example, the control loop frequency of the pressure controller 112b is 10 Hz.

[0151] Here, with reference to the flowchart of FIG. 5 and exemplary embodiments of other figures, a corresponding method for controlling at least one fluid characteristic within a water purification apparatus 300 that produces purified water will be described.

[0152] Typically, this method is performed by the control unit 112 of the water purification apparatus 300. The method may be implemented as program code and stored in the memory 1123 within the control unit 112. Thus, the steps of the method can be defined within a computer program that includes instructions, which, when the program is executed by a computer, such as the control unit 112, cause the computer to execute the method. Accordingly, the steps of the method can also be defined within a computer-readable medium, such as a removable memory like a USB memory stick. The computer-readable medium then includes instructions that, when executed by a computer, cause the computer to execute the method.

[0153] In a typical scenario, the method is implemented when the water purification apparatus is in an operating state and the purification apparatus supplies product water to, for example, a dialysis apparatus. However, it should be recognized that the proposed method may be implemented in a connected or idle state when product water is not being delivered, or alternatively, may be recirculated within an additional recirculation path 381 as described in FIG. 6.

[0154] The method includes a step S1 of detecting at least one fluid characteristic of the purified water in the purified water path 371.

[0155] According to some embodiments, the detecting step S1 includes detecting at least one product fluid characteristic of the product water in the product water path 371c of the purified water path 371. As described above (FIG. 4a), the product water path 371c is disposed downstream of the recirculation path 375. This step implies that product fluid characteristics such as the pressure and flow rate of the product water in the product water path are measured. Typically, the corresponding sensors 308, 309 produce sensor data provided to the control unit 112 that executes the method.

[0156] The method further includes a step S2 of adjusting the flow rate of the water in the recirculation path 375 so as to meet one or more predetermined criteria of the purified water in the purified water path 371 based on at least one detected fluid characteristic.

[0157] According to some embodiments, the adjusting step S2 includes adjusting the flow rate of the water in the recirculation path 375 so as to meet one or more predetermined product water criteria of the product water in the product water path 371c based on at least one detected product fluid characteristic. In other words, the flow rate of the water in the recirculation path 375 is adjusted to control a certain type of product fluid characteristic.

[0158] Alternatively, the adjusting step S2 includes adjusting the flow rate of the water in the recirculation path 375 so as to meet one or more predetermined infiltration water criteria of the infiltration water in the infiltration water path 371a based on at least one detected production fluid characteristic. An example of the infiltration water criterion is that the infiltration water has a certain pressure or temperature.

[0159] For example, the flow rate of the water in the recirculation path 375 is adjusted so that the flow rate of the product water in the product water path 371c is constant or within a predetermined interval. In other words, according to some embodiments, at least one product fluid characteristic includes the flow rate of the product water in the product water path 371c, and at that time, the predetermined product water criterion includes that the flow rate of the product water in the product water path 371c corresponds to a predetermined flow rate.

[0160] In another example, the flow rate of water in the recirculation path 375 is adjusted so that the pressure of the product water in the product water path 371c does not exceed a threshold value. In other words, according to some embodiments, at least one product fluid characteristic includes the pressure of the product water in the product water path 371c. Next, a predetermined product water standard includes that the pressure of the product water in the product water path 371c remains below a predetermined upper pressure level.

[0161] The detecting step S1 and the adjusting step S2 are usually continuously performed in the operating state. Therefore, all changes detected by at least one detector, such as the pressure sensor 308 and the flow rate sensor 309, can trigger the adjusting step S2. In other words, the method includes continuously executing the detecting step S1 and the adjusting step S2 while the water purification device 300 is producing purified water. The predetermined upper pressure level corresponds to, for example, the pressure tolerance level of at least one filter arranged to filter the product water flowing through the product water path 371c, or other arbitrary components arranged within or at a predetermined distance from the product water path 371c.

[0162] According to some embodiments, the method includes a step S3 of activating an alarm function in response to a change in at least one product fluid characteristic. In other words, if a certain change, such as a rapid increase or decrease in pressure, is revealed by detection, this can be regarded as an indicator of a potential error, as exemplified above in relation to FIG. 4a. In such a situation, an alarm function that alerts the user about the potential error may be triggered. The alarm may be a sound, a flashing light, or a text message sent or displayed to the user.

[0163] In some cases, it may be desirable to produce product water at a constant temperature. The temperature is required, for example, by a dialysis apparatus that requires the water purification device 300 to deliver purified water. Thereafter, the temperature of the product water can be appropriately controlled. Accordingly, according to some embodiments, the method includes step S4 of controlling the temperature of the product water flowing within the product water path 371c. This can be done by heating using the heater 302. The temperature can be set to virtually anything, but the range may be limited to 20 to 35°C.

[0164] When the flow rate of the product water is continuously detected, since the amount corresponds to the integrated value of the flow rate, it is also possible to calculate the amount of water that has passed through the product water path 371c. According to some embodiments, the control includes step S5 of estimating the amount of product water produced during a production time period based on the duration of the production time period and the corresponding flow rate of the purified water detected between the production time zones. The production time zone will typically correspond to the time from when production is started until production ends, or, if production is in progress, i.e., if production has not ended, the time up to the present.

[0165] In a second scenario, i.e., when production is in progress, when a desired amount of product water has been produced, a predetermined action such as an alarm or notification can be triggered. The desired amount can be specified, for example, by the user and entered via the user interface. In other words, according to some embodiments, the method includes step S6 of causing a predetermined action when the amount reaches a certain production amount. Actions that can be considered include stopping production, notifying the attached dialysis apparatus, sounding an alarm, etc.

[0166] According to some embodiments, the control includes controlling the fluid characteristics of the purified water passing through the product water port 128 in order to obtain a predetermined flow rate during a predetermined time period to produce a predetermined amount of water. The predetermined amount is, for example, 0.5 to 400 liters. The predetermined amount may correspond, for example, to the amount required for a single dialysis treatment or to the amount required for multiple treatments.

[0167] As described above, it is considered desirable to keep the operating temperature of the RO membrane 324 fairly constant. Thus, according to some embodiments, the method includes measuring the water temperature in the purified water path 371 downstream of the heater 302 disposed in the purified water path. And the adjusting step S2 includes adjusting the flow rate of the water in the recirculation path such that the temperature T_RO of the water flowing through the RO membrane 324 meets a predetermined temperature criterion based on the temperature detected by the temperature sensor 303. As described above, in some embodiments, the adjustment can be performed in this way in combination with or independently of other embodiments described herein.

[0168] FIG. 6 shows in more detail an example of the water purification apparatus 300 according to some embodiments. In other embodiments, the water purification apparatus 300 can include fewer or more components or modules.

[0169] The water purification device 300 in FIG. 6 receives water from a water source 398 such as a portable or potable water sustainable supply source from a patient's home (FIG. 3). In various embodiments, the water purification device 300 can be installed in a room accessible to the water source 398 to provide WFPD to the cycler 20 as discussed herein. The water is optionally filtered using a particle prefilter 334 to remove dirt and sediment before being delivered to the water purification device 300. The water enters the water purification device 300 through a water inlet 333. As described above, the water purification device 300 includes a pretreatment unit 160, an RO unit 170, and a post-treatment module 180. The pretreatment module 160 includes a particle filter and an activated carbon filter, i.e., an activated carbon bed, to further remove contaminants and impurities. The particle filter and the activated carbon filter are embodied in a filter package 331. The filter package 331 is a disposable package. The pretreatment module 160 includes an inlet valve 332 and a constant flow device 330 upstream of the filter package 331. The inlet valve 332 controls the supply water inflow under the control of the control unit 112. The constant flow device 330 provides that the water pressure is above the minimum pressure for the inlet valve 332 and provides a constant flow rate to the tank 350.

[0170] Furthermore, the pretreatment module 160 includes a sampling valve 329 with a sampling port outlet 329a, a tank valve 328, a pretreatment conductivity sensor 327, and a feed water temperature sensor 326 downstream of the filter package 331. The sampling port outlet 329a enables sampling of the feed water, for example, to test chlorine levels. The tank valve 328 controls the flow of the filtered supply water to the tank 350. The pretreatment conductivity sensor 327 monitors the conductivity of the filtered feed water, and the feed water temperature sensor 326 monitors the temperature of the filtered feed water. For example, the temperature of the filtered feed water is required to calibrate the conductivity measurement of the filtered feed water. The described components are included in the feed water path 390. The feed water path 390 is connected to the water inlet 333 and ends at the tank 350. The inlet valve 332 and the tank valve 328 are configured to be controlled by the control unit 112 of the water purification device 300. Water softening in the pretreatment module 160 can be alternatively or additionally achieved using lime softening, ion exchange resins, or antiscalants such as polyphosphates known in the art. The filter package 331 is not required and may not be present in some embodiments and it should be recognized as such.

[0171] As described above, the RO module 170 consists of a tank 350, an RO pump 450, and an RO device 301. The RO device 301 has already been described in detail with reference to FIG. 4a and for further explanation, reference is made to that description. The filtered (or unfiltered) supply water enters the tank 350, for example, from the top of the tank 350. The feed water accumulates in the tank 350 and is sent by the RO pump 450 to the inlet 301a of the RO device 301 (see FIGS. 5 - 7).

[0172] The tank 350 is provided with empty, low, and high level switches 350a, 350b, 350c. The computer program operating on the control unit 112 of the water purification device 300 is configured to control the opening and closing of the inlet valve 332 and the tank valve 328 that are opened during the filling of the tank 350. When the water level in the tank 350 activates its high level switch 350c connected to the control unit 112, it closes. The inlet valve 332 opens again when the water level drops below the low level switch 350b of the tank 350, tripping the low level switch connected to the control unit 112. If the water level in the tank 350 is too high, the excess water is discharged, for example, to the tray 420 or the drain 339 via the tank air vent line 325 and the tank vent 335 (overflow connection). The tank vent 335 is accessible from outside the water purification device 300. The tank vent 335 may be closed, for example, during the transportation of the water purification device 300, so that the water in the tank 350 flows into the tray 420 and prevents the water from flowing out of the water purification device 300.

[0173] The control unit 112 is configured to stop the pumping function of the RO pump 450 when the empty level switch 350a in the tank 350 detects an empty or critically low water level. The RO pump 450 is configured to provide the water flow and pressure required for the reverse osmosis process performed in the RO device 301. For example, as described above with reference to FIG. 4a, the RO device 301 filters water and supplies purified water to its permeate outlet 301b. The water leaving the RO device 301 at the drain outlet 301c is discarded (it may be fed back to the RO pump 450 to save water consumption or alternatively pumped to the drain 339).

[0174] The purified water exiting the RO device 301 is conveyed within the purified water path 371 in the purified water device 300 before being output via the product water port 128. The purified water path 371 consists of a permeate path 371a, a polisher water path 371b, and a product water path 371c (as shown in Figure 4a). The polisher 306 may bypass via a bypass path 371d. The bypass path 371d is connected to the water path upstream of the polisher 306, here the EDI device, and the water path downstream of the EDI device. The purified water leaving the RO device 301 passes through a flow rate sensor 410, a heater 302, and a permeation temperature sensor 303 included in the permeate path 371a. The flow rate sensor 410 monitors the flow rate of the purified water leaving the RO device 301. The heater 302 heats under the control of the control unit 112 and is the purified water leaving the RO device 301. The permeation temperature sensor 303 monitors the temperature of the purified water leaving the RO device 301 directly downstream of the heater 302. An additional conductivity sensor 304 monitors the conductivity of the purified water leaving the RO device 301.

[0175] Downstream of the heater 302, the permeation temperature sensor 303, and the conductivity sensor 304, the purified water enters the post-treatment module 180 via the polisher water path 371b. The post-treatment module 180 includes a polisher 306. The three-way valve 305c is controlled by the control unit 112 and is arranged to selectively direct the purified water flow either to the polisher 306 or to a bypass path 371d for bypassing the polisher 306. The polisher 306 device is configured to produce product water. The product channel valve 307 adjusts the flow rate of the product water in the product water path 371c from the polisher 306. The concentrate path 377c is arranged to return the liquid from the polisher 306 to the tank 350.

[0176] Product water is passed through the product water port 128 and further through the water lines 64 (64a, 64b) of the disposable set 40 connected thereto, and is conveyed to the care site. The disposable set 40 includes two sterilizing filters 70a, 70b. The sterilizing filters 70a, 70b filter the product water exiting the product water port outlet 128 into sterilized product water suitable for injection. According to some alternative embodiments, those filters are removed, or the number of filters is less than or equal to 2 or more than that.

[0177] The drain port 118 defines a first drain path 384 to the drain 339. The drain line 56 of the disposable set 40 is connected to the drain port 118 to pass water such as the used PD fluid from the drain port 118 to the drain 339. Here, the first drain path 384 embodies a part of the cycler drain path existing inside the water purification device 300. The first drain path 384 includes a conductivity sensor 336, a drain path temperature sensor 315, and a drain line valve 341. The conductivity sensor 336 is configured to measure the conductivity of the water in the drain path. The temperature sensor 315 is arranged to measure the temperature of the water in the first drain path 384. The drain line valve 341 is under the control of the control unit 112 and is arranged to adjust the flow rate in the first drain path 384 via the conductivity sensor 336. The first drain path 384 further includes a bypass path 384a arranged to bypass the conductivity sensor 336, the drain path temperature sensor 315, and the drain line valve 341. The bypass path 384a includes a valve 340. The valve 340 is arranged to regulate the flow through the bypass path 384a.

[0178] As shown in FIG. 4a, the control device 305a is arranged at a point downstream of the heater 302, the penetration temperature sensor 303, and the additional conductivity sensor 304 to control the flow rate of purified water in the recirculation path 375 and is configured to return to the tank 350. The product water pressure sensor 308 is arranged to monitor the pressure of the product water in the product water path 301c downstream of the polisher 306. As shown in FIG. 4a, the flow rate sensor 309 is arranged to monitor the flow rate of the product water downstream of the polisher 306. The pressure and flow rate of the product water are supplied to the control unit 112. The control unit 112 is configured to control the operation of the control device 305a. More specifically, the control unit is configured to adjust the flow rate of the water in the recirculation path 375 based on the pressure and flow rate of the product water in order to control the flow rate of the product water to a desired flow rate and the pressure of the product water to a desired pressure. The control device 305a is, for example, an electric flow control valve configured to finely adjust the flow rate of the water in the recirculation path 375.

[0179] The product water valve 305d is arranged to control, under the control of the control unit 112, whether the flow rate of the product goes to the product water port 128 or returns to the tank 350 via the additional recirculation path 381. The discharge valve 396 is arranged to control the flow rate of the water in the additional recirculation path 381. The additional recirculation path 381 is fluidly connected to the product water path 371c via the air trap chamber 319. The product water conductivity sensor 312 is arranged to monitor the conductivity of the product water upstream of the air trap chamber 319. The product water temperature sensor 313 is configured to monitor the temperature of the product water upstream of the air trap chamber 319.

[0180] In operation, a portion of the wastewater exiting the RO device 301 via the fluid path 385a passes through the auxiliary steady flow device 318, which provides a steady flow of the discarded water to a three-way valve 305b (e.g., a three-way solenoid valve) under the control of the control unit 112. The remaining portion of the discarded water returns to the RO pump 450 via a valve 320 (e.g., a manual needle valve) in the first waste path 385b. The three-way valve 305b is configured to selectively switch the discarded water either to the drain 339, or back to the tank 350 via the second drain path 388, or back to the tank 350 via the second drainage path 389. The bypass path 385f is arranged to bypass the auxiliary steady flow device 318. The flow control device 321 is arranged to control the flow rate within the bypass path 385f under the control of the control device 112.

[0181] When the treatment is complete, the water purification device 300 prepares for the disconnection of the disposable line set 40 (e.g., in response to a message received by the cycler 20), covers the product water port 128 and the drain port 118 from the outside, and at the same time closes a lid (not shown) that connects the product water port 128 and the drain port 118 via the path 401a, allowing the heated fluid to flow from the product water port 128 into the drain port 118 and further into the drain 339 via the first drain path 384.

[0182] All meters and sensors described in connection with the water purification device 300 of FIG. 6 are in some embodiments configured to send corresponding signals to the control unit 112.

[0183] To protect the components of the water purification device 300 as much as possible, enhance reliability, and prevent the growth of bacteria, the water purification device 300 provides hardware and programs for cleaning.

[0184] The water purification device 300 also includes a container 392 containing a microbial growth inhibitor. The microbial growth inhibitor is used to prepare a cleaning solution such as citric acid and is introduced into the water passage in some embodiments. As shown, the container 392 is in fluid communication with an inlet 392a of the water purification device 300. In FIG. 6, line 382 connects the container 392 to the water passage of the water purification device 300. Alternatively, the container 392 may be connected via a line (not shown) that leads directly to a disposable cassette 42 operated by the cycler 20, may be connected to the water line 64, or may be connected to the drain line 56.

[0185] Agents that inhibit microbiological growth within container 392 may be suitable physiologically safe acids such as citric acid, citric acid, lactic acid, acetic acid, or hydrochloric acid (or combinations thereof). In one embodiment, container 392 contains citric acid, citrate or a derivative thereof. It is noted that container 392 may also include additives provided together with the acid (such as together with citric acid). Chemical inlet 392a is located, for example, at the front of water purification device 300. A presence sensor (not shown, for example a light sensor) is arranged to sense when container 392 is connected to chemical inlet 392a. A three-way valve 317 under the control of control unit 112 is arranged at chemical inlet 392a to open towards a second pump, which is chemical injection pump 316, and towards tank 350. Chemical injection pump 316 is arranged to supply a disinfecting solution to tank 350. The light sensor is arranged to detect whether a source of cleaning or disinfecting solution is connected or not. If container 392 is removed or not detected by the light sensor, chemical injection pump 316 stops or is not activated and three-way valve 317 closes towards chemical inlet 392a. The three-way valve 317 under the control of control unit 112 can also be used to recirculate water and disinfectant from and to tank 350 during the chemical disinfection, cleaning and / or rinsing phases. Chemical injection pump 316 and valve 310 are arranged within a path 379 that fluidly connects three-way valve 317 and product water path 371c. Valve 310 is arranged to control the flow within path 379.

[0186] In an example of a more detailed disinfection stage, when chemical disinfection is initiated, the level in tank 350 is adjusted to a level just above the low level switch 350b. The control unit 112 starts and operates the RO pump 450 until the empty level switch 350a indicates the presence of air. Next, the RO pump 450 is stopped and the inlet valve 332 is opened. The inlet valve 332 remains open until the empty level switch 350a indicates the presence of water. Thereafter, the chemical injection pump 316 is run until a preset amount of chemical substance solution is inserted into tank 350. When the level in tank 350 reaches a predetermined level, the three-way valve 317 opens the drain 339. The RO pump 450 can operate in two directions to circulate the water in the flow path during the chemical intake stage, creating a turbulent flow and increasing the disinfection time and contact. At the end of the intake stage, the waste bypass valve 321 is opened and the three-way valve 305b is actuated to open the second drain path 388 to drain to the drain 339 and drain the water level in tank 350 to its low level at the low level switch 350b.

[0187] The described pretreatment module 160, RO module 170, and post-treatment module 180 are enclosed inside a single water purification cabinet 110a, except for a filter package 331 that is removably disposed, for example, hingedly, outside the single water purification cabinet 110a. Thereafter, the filter package 331 can be replaced when it is consumed. In an alternative embodiment, the modules can be arranged in separate units. As described above, the purified water is sent from the water purification device 300 to the disposable set 40 via the water line 64. Referring to FIG. 1, the water line 64 supplies the purified water to the water port 282 of the cassette 42 of the disposable set 40. The water line 64 is, in one embodiment, a flexible tube having a first end connected to the product water port 128 of the water purification device 300 and a second end connected to the water port 282 of the cycler 20. The water line 64 is at least 2 meters in length and, in one embodiment, can be longer than 4 meters. The water line 64 allows the water purification device 300 to be installed in a room having an available water source, while the cycler 20 can be installed in a different room where the patient resides, such as a bedroom. The water line 64 can accordingly be as long as necessary to connect the water purification device 300 to the cycler 20.

[0188] FIG. 6 also shows that the disposable set 40 includes a configuration of a drain line 56 arranged to direct water, such as used dialysate, to the drain 339 of the water purification device 300. The drain line 56 is, for example, a tube having a first end connected to the cassette 42 of the cycler 20 and a second end including a drain line connector 58 (FIG. 1) connected to the drain port 118 of the water purification device 300. The drain line 56 may alternatively be flexible and may be longer than 2 meters and, in some embodiments exceeding 4 meters, as long as necessary to connect between the water purification device 300 and the cycler 20. The water line 64 and the drain line 56 in the illustrated embodiment run parallel using a dual lumen tube. Also, the water purification device 300 and the cycler 20 can be arranged in proximity such that the same two-line waterway including the water line 64 and the drain line 56 is, for example, less than 0.5 meters. Further, the water line 64 and the drain line 56 can be separate while the dual lumen water line 64 and the drain line 56 are illustrated.

[0189] The water tray 420 is disposed under the water purification device 300. A liquid sensor 370 is disposed at the bottom of the water tray 420 to detect leakage from the water purification device 300.

[0190] The present disclosure is not limited to the above preferred embodiments. Various alternatives, modifications, and equivalents may be used. Accordingly, the above embodiments should not be regarded as limiting the scope of the disclosure defined by the appended claims.

Claims

1. A water purification device (300), which is a reverse osmosis device (301) configured to produce purified water, the reverse osmosis device (301) including a supply port (301a) and a purified water outlet (301b) arranged to receive supply water, a reverse osmosis pump (450) configured to send the supply water to the supply port (301a), a recirculation path (375) configured to recirculate a part of the purified water from a first point downstream of the reverse osmosis device (301) to a second point upstream of the reverse osmosis device (301), a purified water path (371) configured to convey the purified water from the purified water outlet (301b) to a destination, the purified water path (371) including (i) a permeate water path (371a) arranged upstream of the recirculation path (375) and (ii) a product water path (371c) arranged downstream of the recirculation path (375) to convey the product water to the destination, and the permeate water path (371a) being branched into the recirculation path (375) and the product water path (371c) at the first point, a heater (302) arranged downstream of the reverse osmosis device (301) to heat the purified water flowing in the purified water path (371), a temperature sensor (303) arranged to measure the temperature of the purified water downstream of the heater (302), a control unit (112) configured to control the temperature of the supply water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) based on the temperature detected by the temperature sensor (303), the control unit (112) being configured to control the flow rate through the heater (302), control the reverse osmosis pump (450), and control the temperature of the water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) based on the temperature detected by the temperature sensor (303), The water purification device (300) comprising the above.

2. The water purification device (300) according to claim 1, wherein the heater (302) is arranged in the permeate water path (371a).

3. The water purification device (300) according to claim 1 or 2, wherein the control unit (112) is configured to control the heater (302) so as to control the temperature of the supply water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) based on the temperature detected by the temperature sensor (303).

4. A water purification device (300) according to any one of claims 1 to 3, comprising a control device (305a) configured to control a flow rate within the recirculation path (375), wherein the control unit (112) is configured to control the control device (305a) to control the temperature of the water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) based on the temperature detected by the temperature sensor (303).

5. A water purification device (300) according to any one of claims 1 to 4, comprising a flow rate sensor (410) configured to detect a flow rate of purified water within the permeate path (371a).

6. The water purification device (300) according to claim 5, wherein the temperature of the reverse osmosis membrane (324) of the reverse osmosis device (301) is determined based on a function of the temperature measured by the temperature sensor (303), the output to the heater (302), and the flow rate of the water passing through the reverse osmosis membrane (324) measured by the flow rate sensor (410).

7. The water purification device (300) according to claim 5 or 6, wherein the control unit (112) is configured to control the reverse osmosis pump (450) to a certain pump speed corresponding to a certain flow rate of purified water passing through the permeate path (371a).

8. A water purification device (300) according to any one of claims 1 to 7, wherein the control unit (112) is configured to control the temperature of the supply water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) to a constant temperature.

9. A peritoneal dialysis system, A water purification device, A reverse osmosis device (301) configured to produce purified water, the reverse osmosis device (301) including a supply port (301a) and a purified water outlet (301b) arranged to receive supply water, A reverse osmosis pump (450) configured to send supply water to the supply port (301a), A recirculation path (375) configured to recirculate a part of the purified water from a first point downstream of the reverse osmosis device (301) to a second point upstream of the reverse osmosis device (301), A purified water path (371) configured to convey purified water from the purified water outlet (301b) to a destination, comprising: (i) a permeate path (371a) disposed upstream of the recirculation path (375); and (ii) a product water path (371c) disposed downstream of the recirculation path (375) to convey product water to the destination. The permeate path (371a) branches into the recirculation path (375) and the product water path (371c) at the first point. Purified water path (371). A heater (302) disposed downstream of the reverse osmosis device (301) to heat the purified water flowing in the purified water path (371). A temperature sensor (303) disposed to measure the temperature of the purified water downstream of the heater (302). A control unit (112) configured to control the temperature of the supply water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301), control the flow rate through the heater (302), and control the reverse osmosis pump (450) based on the temperature detected by the temperature sensor (303). A purified water device including the above. A peritoneal dialysis (PD) cycler, arranged and configured to use PD fluid during PD treatment, the PD fluid being mixed using product water from the purified water device (300). PD cycler. A peritoneal dialysis system comprising the above.

10. A method for controlling at least one fluid characteristic in a purified water device, the purified water device comprising a reverse osmosis device (301) configured to produce purified water and a recirculation path (375) configured to recirculate a portion of the purified water from a first point downstream of the reverse osmosis device (301) to a second point upstream of the reverse osmosis device (301). The method includes Configuring the purified water path (371) to include (i) a permeate path (371a) disposed upstream of the recirculation path (375) and (ii) a product water path (371c) disposed downstream of the recirculation path (375). Dividing the permeate path (371a) into the recirculation path (375) and the product water path (371c) at the first point. Using a heater (302) disposed downstream of the reverse osmosis device (301) to heat the purified water flowing in the purified water path (371). Measuring the temperature of the purified water downstream of the heater (302) with a temperature sensor (303). Based on the temperature detected by the temperature sensor (303), controlling the temperature of the feed water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301); Based on the temperature detected by the temperature sensor (303), controlling the flow rate through the heater (302) and controlling the reverse osmosis pump (450) so as to control the temperature of the water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301); A method including the at least one fluid property including the temperature of the water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301).

11. The method according to claim 10, including controlling the heater (302) so as to control the temperature of the feed water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) based on the temperature detected by the temperature sensor (303).

12. The method according to claim 10 or 11, including controlling a control device (305a) configured to control the flow rate in the recirculation path (375) so as to control the temperature of the water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) based on the temperature detected by the temperature sensor (303).

13. The method according to any one of claims 10 to 12, including detecting the flow rate of the purified water in the permeate path (371a) using a flow rate sensor (410).

14. The method according to claim 13, including determining the temperature of the reverse osmosis membrane (324) of the reverse osmosis device (301) based on a function of the temperature measured by the temperature sensor (303), the output to the heater (302), and the flow rate of the water flowing through the reverse osmosis membrane (324) measured by the flow rate sensor (410).

15. The method according to claim 13 or 14, including controlling the reverse osmosis pump (450) to a certain pump speed corresponding to a certain flow rate of the purified water through the permeate path (371a).

16. The method according to any one of claims 10 to 15, including controlling the temperature of the feed water flowing through the reverse osmosis membrane (324) of the reverse osmosis device (301) to a constant temperature.

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