Water purification equipment and method for controlling at least one fluid property in water purification equipment

Abstract

The present disclosure relates to a water purification device and a method for controlling at least one fluid property in the water purification device. The water purification device includes a reverse osmosis device, i.e., an RO device, for producing a pure water stream. The proposed method includes detecting at least one fluid property of the pure water in the pure water path, and based on the at least one detected fluid property, adjusting the flow rate of the water in the recirculation path to meet one or more predetermined criteria for the pure water in the pure water path. The present disclosure also relates to a computer program and a computer program product for implementing the method.

Description

[0001] This application is a divisional application of the invention patent application of Baxter International Inc. and Baxter Healthcare S.A. (filed on June 13, 2018, with application number 201880040187.4 and invention title "Water purification device and method for controlling at least one fluid property in a water purification device"). Technical Field

[0002] The present disclosure relates to a water purification device and a corresponding method for controlling at least one fluid property in a water purification device. The present disclosure also relates to a computer program and a computer program product for implementing the method. Background Art

[0003] When treating patients with acute or chronic renal insufficiency, dialysis treatment is employed. The three main categories of dialysis treatment are hemodialysis HD, peritoneal dialysis PD, and continuous renal replacement therapy CRRT.

[0004] In hemodialysis, the patient's blood is cleaned by passing through an artificial kidney in an extracorporeal membrane system incorporated in a dialysis machine. Blood treatment involves extracorporeal circulation of blood through a dialyzer (a replacement device with a semipermeable membrane), where the patient's blood circulates on one side of the membrane and dialysate circulates on the other side of the membrane. The dialysate includes the main electrolytes of blood with concentrations close to those of electrolytes in the blood of a healthy subject. Additionally, a pressure difference is created between the two compartments of the dialyzer, which are separated by the semipermeable membrane, such that a portion of the plasma fluid passes through ultrafiltration across the membrane into the compartment containing the dialysis fluid.

[0005] CRRT is used as an alternative treatment for patients who are too ill or unstable for standard hemodialysis. It is similar to hemodialysis and utilizes a semipermeable membrane for diffusion and a certain degree of convection. However, compared to hemodialysis, it is a slower form of blood treatment and may continue for several hours to several days.

[0006] In peritoneal dialysis, the dialysis fluid is injected into the patient's peritoneal cavity. The cavity is lined with a highly vascularized peritoneal membrane. Metabolites are removed from the patient's blood by diffusing across the peritoneal membrane into the dialysis fluid. Excess fluid (i.e., water) is also removed by osmosis caused by a hypertonic dialysis fluid. Through the two processes of diffusion and osmotic ultrafiltration, an appropriate amount of solute metabolites and fluid needs to be removed to keep the patient's body fluid volume and composition within appropriate limits.

[0007] There are various types of peritoneal dialysis treatments, including continuous ambulatory peritoneal dialysis ("CAPD"), automated peritoneal dialysis ("APD") including tidal flow APD, and continuous flow peritoneal dialysis ("CFPD").

[0008] CAPD is a manual dialysis treatment. The patient manually connects an implanted catheter to a drainer, which allows the used dialysate fluid to be drained from the peritoneal cavity. Then, the patient connects the catheter to a bag of fresh dialysate fluid and injects the fresh dialysate fluid through the catheter and into the patient. The patient disconnects the catheter from the fresh dialysate fluid bag and allows the dialysate fluid to remain in the peritoneal cavity, where transfer of waste, toxins, and excess water occurs.

[0009] Automated peritoneal dialysis (“APD”) is similar to CAPD in that the dialysis process includes drain, fill, and dwell cycles. However, the APD machine performs the cycles automatically, usually while the patient is sleeping. The APD machine frees the patient from having to perform the process cycles manually and from having to transport supplies during the day. The APD machine is fluidly connected to an infusion catheter and is fluidly connected to a source or bag of fresh dialysate fluid and a fluid drainer. The APD machine pumps fresh dialysate fluid from the dialysate fluid source through the catheter into the patient's peritoneal cavity and allows the dialysate fluid to dwell in the cavity and allows transfer of waste, toxins, and excess water to occur. The APD machine pumps the used dialysate from the peritoneal cavity through the catheter to the drainer. As in the manual process, several drain, fill, and dwell cycles occur during APD. A “last fill” usually occurs at the end of CAPD and APD and remains in the patient's peritoneal cavity until the next treatment.

[0010] Both CAPD and APD are intermittent systems that send the used dialysate fluid to a drainer. The tidal flow system is a modified intermittent system. Instead of removing all the fluid from the patient over a longer period of time, with tidal flow, part of the fluid is removed and replaced after smaller time increments.

[0011] A continuous flow or CFPD system cleans or regenerates the used dialysate fluid rather than discarding it. CFPD systems are generally more complex than intermittent systems.

[0012] CAPD, APD (including tidal flow), and CFPD systems can employ a pumping cassette. The pumping cassette generally includes a flexible membrane that is mechanically moved to push dialysate fluid into and pull it out of the cassette, respectively.

[0013] In one form of peritoneal dialysis, an automated cycler injects and drains the dialysate fluid. This form of treatment can be performed automatically at night while the patient is asleep. The cycler measures the amount of fluid injected and the amount removed to calculate the net fluid removal. The treatment sequence usually begins with an initial drain cycle to empty the peritoneal cavity of the used dialysate fluid. Then, the cycler performs a series of fill, dwell, and drain cycles, usually ending with a fill cycle.

[0014] Peritoneal dialysis typically requires large amounts of dialysis fluid. Typically, at each application or change, a given patient will instill 2 to 3 liters of dialysis fluid into the peritoneal cavity. The dialysis fluid is allowed to dwell for approximately 1 to 3 hours, at which time it is drained and replaced with fresh dialysis fluid. Typically, four such changes are performed each day. Thus, for each patient, 365 days per year, 7 days per week, approximately 8 to 20 liters of dialysis fluid are required per day.

[0015] Dialysis fluid for the above treatment has traditionally been provided in sealed container bags for use. For example, peritoneal dialysis is typically performed using bags with three different concentrations of glucose. Bags of 1 to 6 liters with different glucose concentrations are delivered to the patient's home. The normal daily consumption is approximately 8 to 20 liters of PD dialysis fluid. The fluid is provided in sterile bags of up to 6 liters in size, and the sterile bags are packed in boxes and delivered, for example, monthly for use in the patient's home. For PD patients, these fluid containers can be cumbersome and awkward to handle, and take up a large amount of space in their homes. The bags and boxes also generate a relatively large amount of waste based on weekly or monthly disposal.

[0016] In view of the above, several problems become apparent. The large amounts of fluid required for transportation and storage take up space. Additionally, the use of multiple pre-filled bags generates waste in the form of empty containers and packaging.

[0017] Accordingly, there is a need for a subsystem for an entire peritoneal dialysis PD system that generates dialysis solution at the point of use (e.g., at a PD machine).

[0018] PD dialysis fluid is delivered directly to the patient's peritoneal cavity. Therefore, PD fluid needs to have a certain level of sterility to be suitable for introduction into the patient's peritoneum. Accordingly, PD dialysis fluid is typically pre-mixed and sterilized before being transported to the location of use (usually the patient's home). <\(

[0019] Additionally, in hemodialysis and CRRT, there is a need for a system that generates dialysis solution at the point of use (e.g., at a hemodialysis machine or a CRRT machine).

[0020] In some embodiments, the entire system for hemodialysis, PD, or CRRT includes three main components, namely, a dialysis machine, a water purifier, and a disposable device that operates with the dialysis machine and the water purifier. The dialysis machine is, for example, a PD cycler, a hemodialysis machine, or a CRRT machine. The dialysis machine prepares and concentrates dialysis fluid using purified water from the water purifier.

[0021] The water purifier produces purified water from, for example, tap water at the point where purified water is used. Summary of the Invention

[0022] In some cases, it is desirable to deliver a product water flow rate of a certain magnitude. For example, in order to be able to deliver a certain amount of purified water in a timely manner, or to overcome the pressure drop caused by a filter located downstream of the water purification device. However, the hardware of the water purification device and the filter may deteriorate over time. For example, a disinfection-grade filter may become blocked by bacteria and endotoxins and possibly other substances. This may affect the product water flow rate from the water purification device. Therefore, the throughput at a constant pressure will decrease over time. Therefore, the amount of purified water produced by the water purification device may be uncertain. Therefore, an object of the present disclosure is to control the properties of the product water flow, for example, to maintain a constant (or reasonably constant) flow rate or pressure. Another object is to keep the operating points (such as pressure, temperature, or flow rate) of the components in the water purification device within a certain range.

[0023] These and other objects are achieved at least in part by the devices and methods according to the independent claims and by the embodiments of the dependent claims.

[0024] According to a first aspect, the present disclosure relates to a water purification device for producing purified water. The water purification device includes a reverse osmosis (RO) device, an RO pump, a recirculation path, a purified water path, a product water path, a control device, at least one detector, and a control unit. The reverse osmosis (RO) device is arranged to produce a purified water flow. The RO device includes a supply inlet arranged to receive feed water and a purified water outlet. The RO pump is arranged to pump the feed water to the supply inlet. In addition, the recirculation path is arranged to recirculate a portion of the purified water flow from a first point (position) downstream of the RO device to a second point upstream of the RO device. The purified water path is arranged to transport the 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 to transport the product water to the product water port. The control unit is configured to control the control device based on the fluid properties detected by the at least one detector to adjust the flow rate of the purified water in the recirculation path. The at least one detector is arranged to detect the product fluid properties of the product water in the product water path. The control unit is also configured to control the control device based on the product fluid properties detected by the at least one detector to control the product fluid properties of the product water in the product water path to meet one or more predetermined product water standards. The at least one detector includes a flow sensor, and the product fluid property detected by the flow sensor is the flow rate of the product water in the product water path. Additionally, the one or more predetermined product water standards include that the flow rate of the product water in the product water path corresponds to a predetermined flow rate.

[0025] Thus, one or several fluid properties in the purified water path of the water purification device can be controlled. More specifically, one or several product fluid properties of the product water in the dialysis machine can be controlled such that the desired product fluid properties are maintained throughout the production process and also during, for example, start-up and shut-down. Here, the desired flow rate of the product water can be maintained over time.

[0026] According to some embodiments, wherein the at least one detector includes a pressure sensor, wherein the product fluid property detected by the pressure sensor is the pressure of the fluid in the product water path, and wherein the one or more predetermined product water standards include that the pressure of the product water in the product water path is kept below a predetermined higher pressure level, and / or the pressure of the product water in the product water path corresponds to a predetermined pressure. Thus, the pressure of the product water in the product water path can be controlled to be maintained within the range desired for optimal operation. Thus, component breakage or deterioration due to excessive pressure in the product water path can be avoided.

[0027] According to some embodiments, the at least one filter is arranged to filter the product water flowing through the product water path, wherein the predetermined higher pressure level corresponds to the pressure tolerance level of the at least one filter or any other component arranged in the product water path.

[0028] When water is pumped through the filter, bacteria and endotoxins and possibly other substances may reduce the permeability of the filter arranged in connection with the product water path. This means that for a given pressure, the throughput will decrease over time. By using the proposed technique, the pressure of the product water in the product water path can be increased up to the maximum allowed level to compensate for this behavior.

[0029] 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 property detected by the at least one detector. Thus, if a suspected error is detected, the operator or patient can be warned.

[0030] According to some embodiments, in order to produce a predetermined amount of water, 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. Thus, the production volume required by the dialysis machine can be produced. The required volume is typically between 0.5 liters and 400 liters, for example, 1, 2, 5, 10, 20, 50, 70, 90, 150, 200 or 300 liters.

[0031] According to some embodiments, the water purification device includes a heater which is arranged to heat the product water flowing in the product water path. Thus, product water having the temperature required by the dialysis machine can be produced. The heater can also be used to control the temperature of the RO membrane of the RO device.

[0032] According to some embodiments, the water purification device includes a temperature sensor arranged to measure the temperature of water downstream of the heater in the purified water path. According to these embodiments, the control unit is configured to control the control device based on the temperature detected by the temperature sensor to control the temperature of the water flowing through the RO membrane of the RO device. Thus, the temperature of the RO membrane can be kept quite constant, which may be desirable for operation.

[0033] According to some embodiments, the water purification device includes a tank arranged to receive water from an external water source and supply the water to the supply inlet.

[0034] According to some embodiments, the water purification device includes a polisher device arranged downstream of the recirculation loop in the purified water path. The polisher device includes, for example, an electro-deionization (EDI) device.

[0035] According to some embodiments, the water purification device includes a permeate water path arranged to transport purified water from the purified water outlet of the RO device to the inlet of the polisher device.

[0036] According to some embodiments, the product water path is arranged to transport purified water from the outlet of the polisher device to the product water port.

[0037] According to a second aspect, the present disclosure relates to a method for controlling at least one fluid property in a water purification device for producing purified water. The water purification device includes: a reverse osmosis device, i.e., an RO device, for producing a purified water stream; and 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, which includes detecting at least one product fluid property of the product water in the product water path of the purified water path, wherein the product water path is arranged downstream of the recirculation path; based on the at least one detected fluid property, 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, which includes based on the at least one detected product fluid property, adjusting the flow rate of the water in the recirculation path to meet one or more predetermined product water criteria for the product water in the product water path. The at least one product fluid property includes the flow rate of the product water in the product water path, wherein the 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.

[0038] Thus, as described above, the product fluid properties can be controlled to meet specific criteria defined, for example, by a manufacturer or a user. As a result, water production can be more efficient and dialysis treatment can be safer. The method is also capable of making smaller and faster changes to the product water flow rate compared to when only the pumping frequency for supplying water to the RO device is adjusted.

[0039] According to some embodiments, the method includes evaluating 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 during the production time period. The possibility of controlling the pressure makes it possible to avoid high pressure in the product water path, which in the worst case could lead to a malfunction.

[0040] According to some embodiments, the method includes triggering a predetermined action when the amount reaches a predetermined production amount. For example, when the required amount has been produced, an alarm signal or action (e.g., sending a message to a dialysis machine) can be triggered.

[0041] According to some embodiments, the at least one product fluid property includes the pressure in the product water path, wherein the one or more predetermined product water criteria include keeping the pressure of the product water in the product water path below a predetermined higher pressure level.

[0042] According to some embodiments, the method includes measuring the temperature of the water downstream of a heater disposed in the purified water path in the purified water path. According to these embodiments, the regulation then includes adjusting the flow rate of the water in the recirculation path based on the temperature detected by the temperature sensor such that the temperature of the water flowing through the RO membrane of the RO device meets a predetermined temperature criterion.

[0043] Thus, the temperature span of the water entering the RO membrane will depend less on the temperature of the inlet water and the ambient temperature because the recirculation of the heated purified water can be used to increase the temperature of the water in the tank. As a result, the filtration behavior of the membrane will be more stable.

[0044] According to some embodiments, the method includes continuously performing detection and regulation while the water purification device produces purified water.

[0045] According to some embodiments, the method includes activating an alarm function in response to a change in at least one detected product fluid property. Thus, the proposed method according to these embodiments also enables the water purifier to detect a sudden change in pressure, such as the breakthrough of a filter, which means a lower pressure drop, thus a lower pressure and an increased flow rate in the product water path. Alternatively, a leak between the water purifier and the filter will also result in a pressure drop, which will cause the alarm to sound.

[0046] According to some embodiments, a predetermined higher pressure level corresponds to the pressure tolerance level of at least one filter, or corresponds to the pressure tolerance level of any other component arranged in the product water path or arranged at a predetermined distance from the product water path, and the at least one filter is arranged to filter the product water downstream of the product water path.

[0047] According to some embodiments, to produce a predetermined amount of water, the control includes controlling the fluid properties of the product water to obtain a predetermined flow rate during a predetermined period of time. In addition, even if communication with the dialysis machine is lost, the water purifier can continue to deliver the required amount to the dialysis machine. The predetermined amount is typically between 0.5 liters and 400 liters.

[0048] According to some embodiments, the method controls the temperature of the product water flowing in the product water path.

[0049] According to some embodiments, the polishing device is arranged downstream of the recirculation loop in the purified water path, and the product water path is then arranged to transport the product water from the outlet of the polishing device to the product water port.

[0050] According to a third aspect, the present disclosure relates to a computer program comprising instructions that, when executed by a computer, cause the computer to perform the methods described above and below.

[0051] According to a fourth aspect, the present disclosure relates to a computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the methods described above and below. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The following will now be described with reference to the accompanying drawings, which are provided by way of non-limiting example, in which:

[0053] Figure 1 is a front view of an embodiment of a PD dialysis system having point-of-care dialysis fluid production using purified water from a water purification device.

[0054] Figure 2 is associated with Figure 1 a front view of an embodiment of a disposable device for use with the system shown in

[0055] Figure 3 is a schematic diagram of some functional components of a water purification device.

[0056] Figure 4a shows a first exemplary embodiment of a water purification device 300 including an RO device 301.

[0057] Figure 4b shows the functions of the control unit of the water purification device 300.

[0058] Figure 5 A flowchart showing a method for use in a dialysis machine.

[0059] Figure 6 An exemplary water purification device is shown in more detail. Detailed Description

[0060] When using a water purification device, for example, at the point of care, it may 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.

[0061] 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 cause damage to the fluid system and other hardware in or connected to the water purification device. In addition, if the product water flow rate or pressure is too high, the filter in the dedicated pipeline device arranged to supply product water to, for example, a dialysis machine may rupture, which may lead to the risk of bacteria and endotoxins reaching the patient.

[0062] Therefore, the proposed technology presents a method for controlling the product water flow rate through a water purification device based on one or more product water properties or parameters, such as the flow rate, pressure, or temperature of the product water in the product water path. This control is achieved, 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 properties of the purified water, such as pressure or temperature.

[0063] To better understand the proposed technology, the water purification device will be described below as part of a peritoneal dialysis system, and the proposed technology can be implemented in this water purification device. However, for producing dialysis fluid to be used in hemodialysis or CRRT treatments to be performed by the system at the point of care or use point, the proposed technology can also be implemented in water purification devices for producing purified water for other types of dialysis systems (such as hemodialysis or CRRT systems).

[0064] Now referring to the drawings, specifically referring to Figure 1 , a peritoneal dialysis system with point-of-use dialysis fluid production is shown by system or HomeChoice Recycling machines, it is understood that those recycling machines need to update the program to execute and use the point-of-use dialysis fluid produced according to system 10a. To this end, the recycling machine 20 includes a control unit 22 having at least one processor and at least one memory. The control unit 22 also includes a wired or wireless transceiver for sending information to and receiving information from the water purification device 300. The water purification device 300 also includes a control unit 112 having at least one processor and at least one memory. The control unit 112 also includes a wired or wireless transceiver for sending information to and receiving information from the control unit 22 of the recycling machine 20. Wired communication can be, for example, via an Ethernet connection. Wireless communication can be via Bluetooth TM , WiFi TM , Zigbee , Z-Wave , any one of wireless universal serial bus ("USB") or infrared protocol, or via any other suitable wireless communication technology. The control unit 22 includes a computer program that includes instructions that, when the program is executed by the control unit 22, cause the control unit 22 and the water purification device to execute any one or several of the methods and programs according to any of the embodiments disclosed herein. The instructions can be stored on a computer-readable medium such as a portable storage device (e.g., USB memory, portable computer, or the like) and loaded into the control unit 22.

[0065] The recycling machine 20 includes a housing 24 that houses equipment programmed via the control unit 22 to prepare fresh dialysis solution at the point of use, pump the freshly prepared dialysis fluid to the patient P, allow the dialysis fluid to dwell within the patient P, and then pump the used dialysis fluid to the drain. At Figure 1In it, the water purification device 300 includes a first discharge path 384 that leads to a discharger 339, which can be a housing discharger or a discharge container. Equipment programmed via the control unit 22 to prepare fresh permeate solution at the point of use may include equipment for a pneumatic pump system, including but not limited to: (i) one or more positive pressure reservoirs, (ii) one or more negative pressure reservoirs, (iii) a compressor and a vacuum pump both under the control of the control unit 22, or a single pump that generates positive and negative pressures under the control of the control unit 22 to provide positive and negative pressures for storage at one or more positive pressure reservoirs and negative pressure reservoirs, (iv) a plurality of pneumatic valve chambers for transmitting positive and negative pressures to a plurality of fluid valve chambers, (v) a plurality of pneumatic pump chambers for transmitting positive and negative pressures to a plurality of fluid pump chambers, (vi) a plurality of electrically actuated on / off electromagnetic pneumatic valves under the control of the control unit 22 located between the plurality of pneumatic valve chambers and the plurality of fluid valve chambers, (vii) a plurality of electrically actuated variable throttle pneumatic valves under the control of the control unit 22 located between the plurality of pneumatic pump chambers and the plurality of fluid pump chambers, (viii) in one embodiment, a heater under the control of the control unit 22 for heating the dialysis fluid when mixing the dialysis fluid, and (viii) a plug 26 under the control of the control unit 22 for closing the patient and discharge lines in case of alarms and other situations.

[0066] In one embodiment, the plurality of pneumatic valve chambers and the plurality of pneumatic pump chambers are located on the front surface or surface of the housing 24 of the circulator 20. The heater is located inside the housing 24 and, in some embodiments, includes a heating coil that contacts a heating plate under a heating cover ( Figure 1 not visible in it) and the heating plate is located at the top of the housing 24.

[0067] Figure 1 The circulator 20 in it further includes a user interface 30. In one embodiment, the control unit 22 includes a video controller that 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 that can operate with a touch screen placed over the video monitor 32 for inputting commands to the control unit 22 via the user interface 30. The user interface 30 may also include one or more electromechanical input devices, such as membrane switches or other buttons.

[0068] Figure 1The water purification device 300 therein further includes a user interface 120. The control unit 112 of the water purification device 300 may then include a video controller, which may 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 may similarly operate with a touch screen placed over the video monitor 122 for inputting commands into the control unit 112. The user interface 120 may also include one or more electromechanical input devices, such as membrane switches or other buttons. The control unit 112 may also include an audio controller for playing sound files, such as alarm or warning sounds, at one or more speakers 124 of the water purification device 300.

[0069] Additionally referring Figure 2 , a disposable device 40 is shown. The disposable device 40 is also shown Figure 1 in which the disposable device 40 cooperates with a cycler 20 to move fluid inside the disposable device 40, for example, to mix dialysis fluid as discussed herein. The disposable device 40 in the illustrated example includes a disposable cartridge 42, which may include a planar rigid plastic sheet covered with a flexible membrane on one or both sides. The membrane pressed against the housing 24 of the cycler 20 forms a pumping and valve membrane. Figure 2 It is shown that the disposable cartridge 42 includes a fluid pump chamber 44 that operates with a pneumatic pump chamber located at the housing 24 of the cycler 20, and a fluid valve chamber 46 that operates with a pneumatic valve chamber located at the housing 24 of the cycler 20.

[0070] Figure 1 and Figure 2 It is shown that the disposable device 40 includes a patient line 50 that extends from a patient line port of the cartridge 42 and terminates at a patient line connector 52. Figure 1 It is shown that the patient line connector 52 is connected to a patient transfer device 54, which in turn is connected to an internal retention cartridge located in the peritoneal cavity of a patient P. The disposable device 40 includes a drain line 56 that extends from a drain line port of the cartridge 42 and terminates at a drain line connector 58. Figure 1 It is shown that the drain line connector 58 is removably connected to a drain port 118 of the water purification device 300 to receive used dialysis fluid from the cycler 20.

[0071] Figure 1 and Figure 2Also shown is that the disposable device 40 includes a heater / mixing line 60 that extends from the heater / mixing line port of the cartridge 42 and terminates at a heater / mixing bag 62, which will be discussed in more detail below. The disposable device 40 includes an upstream water line portion 64a that extends to the water inlet of the reservoir 66. A downstream water line portion 64b extends from the water outlet 66b of the reservoir 66 to the cartridge 42. In the example shown, the upstream water line portion 64a begins at a water line connector 68 and is located upstream of the reservoir 66. Figure 1 Shown is that the water line connector 68 is removably connected to the product water port 128 of the water purifier 110.

[0072] The water purification device 300 outputs pure water and water suitable for, for example, peritoneal dialysis ("WFPD"). WFPD is water suitable for delivering dialysis fluid to the peritoneal cavity of a patient P. WFPD is, for example, water for dialysis or water for injection.

[0073] In one embodiment, a sterilizing grade filter 70a is placed upstream of a sterilizing grade filter 70b. The filters 70a and 70b can be placed in the upstream water line portion 64a of the reservoir 66. The sterilizing grade filters 70a and 70b can be through-type filters without an intercepting line. The pore size for sterilizing the filters can be, for example, less than a micron, such as 0.1 or 0.2 microns. Suitable sterilizing grade filters 70a and 70b can be, for example, Pall IV-5 or GVSSpeedflow filters, or filters provided by the assignee of the present disclosure. In an alternative embodiment, only one or more than two sterilizing grade filters are placed in the upstream water line portion 64a of the reservoir 66. One or several sterilizing grade filters can be arranged close to the reservoir 66 so that the disposable device 40 is easier to fold. In a further alternative embodiment, there is no sterilizing grade filter in the water line portion 64a. The sterilizing 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.

[0074] Figure 2 Also shown is that a last bag or sample line 72 can be provided that extends from the last bag or sample port of the cartridge 42. The last bag or sample line 72 terminates at a connector 74 that can be connected to a mating connector of a pre-mixed last fill bag for dialysis fluid, or to a sample bag or other sample collection container. If desired, the last bag or sample line 72 and the connector 74 can alternatively be used for a third type of concentrate.

[0075] Figure 1 and Figure 2Shown is a disposable device 40 including a first concentrate line 76 that extends from a first concentrate port of the cartridge 42 and terminates at a first cartridge concentrate connector 80a. A second concentrate line 78 extends from a second concentrate port of the cartridge 42 and terminates at a second cartridge concentrate connector 82a.

[0076] Figure 1 Shown is a first concentrate container 84a containing a first concentrate, such as a glucose concentrate, and the first concentrate is pumped from the container 84a through a container line 86 to a first container concentrate connector 80b that mates with the first cartridge concentrate connector 80a. A second concentrate container 84b contains a second concentrate, such as a buffer concentrate, and the second concentrate is pumped from the container 84b through a container line 88 to a second container concentrate connector 82b that mates with the second cartridge concentrate connector 82a.

[0077] To initiate treatment, the patient P typically loads the cartridge 42 into the cycler and, in a random or specified order: (i) places the heater / mixing bag 62 on the cycler 20, (ii) connects an upstream water line section 64a to the product water port 128 of the water purification device 300, (iii) connects the drain line 56 to the drain port 118 of the water purification device 300, (iv) connects the first cartridge concentrate connector 80a to the first container concentrate connector 80b, and (v) connects the second cartridge concentrate connector 82a to the second container concentrate connector 82b. At this point, the patient connector 52 remains covered. Once fresh dialysis fluid is prepared and verified, the patient line 50 is primed with the fresh dialysis fluid, after which the patient P can connect the patient line connector 52 to the transfer device 54 for treatment. Each of the above steps can be graphically shown at the video monitor 32 and / or provided via a voice wizard from the speaker 34.

[0078] The water purification device 300 will now be described in more detail.

[0079] In Figure 3 is a schematic diagram of the functional components of the water purification device 300, and the water purification device 300 includes a pretreatment module 160, a reverse osmosis (RO) module 170, and a post-treatment module 180. The water purification device 300 includes an inlet port 399 for supplying water from a water source 398 (such as tap water) into the water purification device 300 for water purification. The incoming water from the water source is supplied through the inlet port 399 into the pretreatment module 160.

[0080] Preprocessing module

[0081] The pretreatment module 160 processes the influent water using a particle filter and an activated carbon bed.

[0082] The particle filter is arranged to remove particles such as clay, silt, and silica from the influent water. The particle filter is arranged to inhibit micron-sized particles, and optionally also larger endotoxin molecules, from the influent water.

[0083] The activated carbon bed is arranged to remove chlorine and chlorine-containing components from the influent water, and to absorb toxic substances and pesticides. In an exemplary embodiment, the activated carbon bed is arranged to remove one or more of hypochlorite, chloramine, and chlorine. In a further exemplary embodiment, the activated carbon bed is also arranged to reduce the total organic carbon (TOC) of the influent water including pesticides.

[0084] In some embodiments, the particle filter and the activated carbon bed are integrated in a single consumable component. The consumable component is replaced at a predetermined interval, for example, according to the quality of the influent water. For example, before the water purification device 300 is first used at the point of care, the quality of the influent water is inspected and determined by a qualified person.

[0085] Optionally, the pretreatment module 160 includes an ion exchange device for protecting downstream devices such as a reverse osmosis (RO) membrane and a polisher.

[0086] The pretreatment module 160 thus filters the influent water and delivers the pretreated water to the downstream RO module 170.

[0087] RO module

[0088] The RO module 170 removes impurities such as microorganisms, pyrogens, and ionic materials from the filtered water by reverse osmosis through the pretreated water. 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 semi-permeable membrane. Thus, the pretreated water flow, called the feed water, is divided into a retentate flow and a permeate flow. In an exemplary embodiment, the retentate water can pass through one or both of a first retentate path and a second retentate path. The first retentate path recycles the retentate water back to the feed water path of the RO pump so as to be supplied back to the RO device again. The recycled retentate water increases the feed flow rate into the RO device so that a sufficient flow rate passes through the retentate side of the RO membrane, thereby minimizing fouling and scaling of the RO membrane. The second retentate path directs the retentate water to drain. This keeps the concentration level on the retentate side low enough to achieve an appropriate and desired permeate fluid concentration. If the solute content of the feed water is low, a portion of the drain flow can also be diverted back to the inlet side of the RO membrane, thereby increasing the water efficiency of the water purification device 300.

[0089] The RO module 170 thus processes the pretreated water and delivers the permeate water to the downstream post-treatment module 180.

[0090] Postprocessing module

[0091] The post-treatment module 180 polishes the permeate water to further remove ions from the permeate water. A polishing device such as an electrodeionization (EDI) device or a mixed bed filter device is used to polish the permeate water.

[0092] The EDI device uses electrodeionization to remove ions that have permeated into the RO membrane from the permeate water, such as aluminum, lead, cadmium, chromium, sodium, and / or potassium. The EDI device uses electricity, ion exchange membranes, and resins to deionize the permeate water and separate dissolved ions, i.e., impurities, from the permeate water. The EDI device produces polished water, which is polished to a higher purity level than the purity of the permeate water by the EDI device. The EDI device has an antibacterial effect on the product water and can reduce the amount of bacteria and endotoxins in the water due to the electric field in the EDI device. In one embodiment, the EDI device has a water production rate of 70 - 210 ml / min. Therefore, the capacity of the EDI device sets a limit on the flow rate of the product water.

[0093] The mixed bed filter device includes a column or container having a mixed bed ion exchange material.

[0094] The polished water, also referred to herein as product water, is then ready for delivery 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., water for dialysis. In one embodiment, the product water is water for injection. In an exemplary embodiment, a disposable device 40 including a water pipeline 56 is arranged to the water purification device 300 for delivering the product water to the point of use. Optionally, the water purification device 300 includes a discharge port 118. The discharge port 118 is an exemplary embodiment for receiving, for example, used fluid from a PD patient via a discharge pipeline 64 for further transportation via a first discharge path 384 inside the water purification device 300 to the discharger 339 of the water purification device 300. As an alternative, the discharge port 118 receives a sample of a prepared mixed solution for further transmission to a conductivity sensor arranged in the water purification device 300 (e.g., in the first discharge path 384). The disposable device 40 is arranged here with sterile filters 70a, 70b for filtering the product water from the water purification device 300 to ensure the quality of the product water is the same as that of water for injection.

[0095] Therefore, the product water collected in the reservoir bag 66 has passed through one or several sterile filters of the disposable device 40 for removing bacteria and endotoxins (i.e., producing sterile product water). According to one embodiment, the sterile filters are redundant.

[0096] By collecting sterile product water in the reservoir bag 66, the water purification device 300 and the circulation machine 20 are separated in terms of pressure, so that the high pressure required to push water through the sterile disinfection-grade filter does not affect the circulation machine 20.

[0097] The control unit 112 of the water purification device 300 is arranged to set the water purification device 300 to different operating states, for example, standby (STANDBY), connect (CONNECT), idle (IDLE), run (RUN) and maintenance (MAINTENANCE). The water purification device 300 is arranged to act according to commands from the circulation machine 20.

[0098] When the water purification device 300 is set to the standby state when it is powered on but not in use.

[0099] In the standby (STANDBY) state, the water purification device 300 waits for commands to connect (CONNECT) or maintenance (MAINTENANCE).

[0100] The main steps of different states are explained. Steps for reducing risks are omitted, such as taking the comparison of flow sensors and testing that the flow path has no leaks as examples.

[0101] Status CONNECT

[0102] During the state connect (CONNECT), the system tests the sensors and checks the EDI device to see if the system is ready when it receives a command to enter the idle (IDLE) state. The state connect (CONNECT) can also include flushing certain components in, for example, the pretreatment module 160.

[0103] It is usually also required that the patient samples the influent water sample at the sampling port after the pretreatment module 160. What is checked in this sampling is that the level of chlorine (including hypochlorite, chloramine and chlorine) is lower than the permitted level.

[0104] When all steps of the state connect (CONNECT) have been executed, the system is ready to run.

[0105] Status IDLE

[0106] In this state, the water purification device 300 waits for the return of fluid conductivity measurement (when a newly prepared dialysis fluid is to be tested) or waits for a new request for supply product water from the circulation machine 20.

[0107] In this state, the water purification device 300 can prepare to deliver product water by itself. The water purification device 300 then starts to produce product water, but instead of delivering the product water outside the product port 128, the produced product water is recycled to the tank 350 until the product water reaches a stable conductivity level and the RO device is operating at the desired operating point of the RO device 301.

[0108] The water purification device 300 occasionally recirculates the water path to minimize the start-up time of the water production phase.

[0109] The IDLE state may also include flushing certain components in, for example, the pretreatment module 160.

[0110] Status RUN

[0111] In the RUN state, the water purification device 300 supplies product water (e.g., the amount required by the circulator 20) to the disposable device reservoir bag 66.

[0112] Now reference will be made to Figure 4a 、 Figure 4b and Figure 5 to describe the proposed technology in further detail.

[0113] Figure 4a A water purification device 300 including an RO device 301 is shown. It should be noted that Figure 4a is only a conceptual diagram and only shows the parts of the water purification device 300 related to the proposed technology. A more detailed illustration of the exemplary water purification device 300 and its operation is provided Figure 6 provided.

[0114] Figure 4a The water purification device 300 of

[0115] includes an RO device 301, a tank 350, an RO pump 450, a feed water path 390, a recirculation path 375, a pure 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.

[0116] The feed water path 390 is arranged to transport feed water to the supply inlet 301a. The feed water path 390 is fluidly connected to the supply inlet 301a.

[0117] The tank 350 is arranged in the feed water path 390 for collecting water. More specifically, the tank 350 is arranged to receive water from an external water source and supply the water to the supply inlet 301a. According to some embodiments, the tank 350 is optional and is represented by a dashed line in Figure 4a it.

[0118] The RO pump 450 is arranged in the feed water path 390 to pump the feed water to the supply inlet 301a. The RO pump 450 is arranged downstream of the tank 350 (when present). The RO pump 450 is configured to be controlled to a specific pump speed corresponding to a specific flow rate of the permeate water flow. As the permeability of the RO membrane 324 increases with the increase of the feed water temperature, the relationship between the pump speed and the flow rate depends on the temperature of the water supplied to the supply inlet 301a and thus on the temperature of the RO membrane 324.

[0119] The product water port 128 is arranged to supply product water to, for example, a dialysis machine via dedicated plumbing means. A disinfection grade filter (not shown) is typically located in the plumbing means outside the water purification device 300 downstream of the product water port 128.

[0120] The recirculation path 375 is arranged to recirculate a portion of the pure 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 pure water from a point downstream of the RO device 301 to the feed water path 390 inside the water purification device 300. In Figure 4a the example, the pure water is recirculated to the tank 350 and supplied again to the supply inlet 301a of the RO device 301. However, the pure water can alternatively be directly recirculated to the water pipeline upstream of the RO pump 450.

[0121] The pure water path 371 is fluidly connected to the pure water outlet 301b and fluidly connected to the product water port 128. The pure water path 371 is configured to transport pure water from the pure water outlet 301b to the product water port 128. The pure water path 371 includes a permeate water path 371a and a product water path 371c. The product water path herein refers to the portion of the pure water path 371 closest to the product water port 128, where fluid properties such as pressure and flow rate are the same (or similar) to those in the product water port 128.

[0122] The heater 302 is arranged to heat the product water flowing in the product water path 371c. The heater 302 is, for example, a heater arranged to heat the pure water produced by the RO device 301. In addition, inFigure 4a In the example of Figure 4a , the purified water leaving the RO device 301 also passes through a flow sensor 410 and a temperature sensor 303 included in the permeate water path 371a.

[0123] The purified water path 371 includes a polishing device 306, such as an electrodeionization (EDI) device. Optionally, the polishing device 306 is a mixed bed filter device. The polishing device 306 is arranged downstream of the recirculation loop 374 in the purified water path 371. Thus, the polishing device 306 is arranged downstream of the point where the recirculation path 375 in the purified water path 371 is connected to the purified water path. The polishing device 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 transport purified water from the purified water outlet 301b of the RO device 301 to the inlet of the polishing device 306, and the product water path 371c is arranged to transport purified water from the outlet of the polishing device 306 to the product water port 128.

[0124] The present disclosure is based on the insight that by controlling the portion of the permeate flow produced by the RO device that is recirculated to the feed inlet 301a, fluid properties such as pressure or flow rate of the product water in the product water path 371c can be controlled. A control device 305a (such as an electrically controllable valve) is arranged to enable such control. In other words, the control device 305a is arranged to regulate the flow rate of the purified water in the recirculation path 375. According to some embodiments, the control device 305a is configured to receive control data and regulate the proportion of the recirculation of the permeate flow based on the control data. The control data can 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.

[0125] As described above, when operating the water purification device, the proposed technique is capable of controlling at least one fluid property such as flow rate or pressure in the product water path 371c. According to some embodiments, the proposed technique is capable of controlling other properties such as the temperature of the RO membrane 324 or the operating point of the RO device, such as permeate fluid properties. To achieve such control, it is necessary to measure or at least detect or evaluate the relevant fluid property (or properties) in some way. Therefore, at least one detector is arranged to detect the fluid property of the purified water in the purified water path 371.

[0126] According to some embodiments, at least one detector is arranged to detect a product fluid property of product water in the product water path 371c. The at least one detector can be implemented in a variety of ways. According to some embodiments, the at least one detector is configured to provide product fluid property data, thereby defining at least one product fluid property. According to some embodiments, the control is based on other properties, such as the permeate fluid property, for example, the temperature of the pure water flowing in the permeate water path 371a.

[0127] In Figure 4a , the at least one detector is a flow sensor 309 and a pressure sensor 308. Then the product fluid property measured by the flow sensor 309 is the flow rate of the product water in the product water path 371c. The product fluid property measured by the pressure sensor 308 is the pressure in the product water path 371c. Additionally, a temperature sensor 303 is arranged to measure the temperature of the pure water in the permeate water path 371a downstream of the heater 302.

[0128] The control unit 112 generally includes one or more microprocessors 1122 and / or one or more circuits, such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc.

[0129] The control unit 112 may further include at least one memory 1123, such as a non - transitory memory unit (e.g., hard disk drive, flash memory, optical disc, etc.) and / or a volatile storage device (e.g., dynamic random access memory (DRAM)).

[0130] The control unit 112 further includes an interface 1121, which is configured to be able to communicate with other components of the water purification device 300 (e.g., transmit control data to and receive sensor data from the other components). Specifically, the interface 1121 is configured to be able to communicate with the control device 305a and at least one detector (e.g., the pressure sensor 308 and / or the flow sensor 309).

[0131] The control unit 112 is configured as a functional part of the water purification device 300. Specifically, the control unit 112 is configured to implement all embodiments of the proposed techniques described herein, including the Figure 6 described methods. To achieve this, the control unit 112 is configured to receive fluid property data from at least one detector and send control data to the control device 305a. More specifically, the control unit 112 is configured to control the control device 305a based on the fluid properties detected by at least one detector to adjust the flow rate of the pure water in the recirculation path 375, for example, to meet one or more predetermined criteria of the pure water in the pure water path 371. The fluid properties are measured, for example, by any sensor in the pure water path 371.

[0132] According to some embodiments, the control unit 112 is configured to control the control device 305a based on fluid properties detected by at least one detector (e.g., the pressure sensor 308 and / or the flow sensor 309) to control the product fluid properties of the product water in the product water path 371c to meet one or more predetermined product water standards. In other words, the control unit 112 is configured to control the flow rate of the water in the recirculation path 375 so as to meet one or more criteria, such as obtaining a specific fluid property in the product water flow, e.g., a specific pressure or flow rate.

[0133] As described above, different product fluid properties can be controlled. Thus, the product water standards can include one or more adjustment conditions. Some examples will now be given. It must be understood that those examples can be used alone or in combination. In its simplest form, at least one product water standard includes only a single condition.

[0134] In a first example, the goal of the control is to achieve a constant product water flow rate. The control criterion will then be to 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 generally the same (or at least approximately the same) throughout the 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, e.g., 150 ml / min or 250 ml / min. If a constant product water flow rate can be obtained, it is easy to evaluate how long it will take to produce a certain amount of product water.

[0135] For example, the water purification device 300 can be controlled to produce product water at a certain constant product water flow rate during a predetermined period of time. In other words, according to some embodiments, in order to produce a predetermined amount of water, 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 period of time. The predetermined amount is, for example, between 0.5 liters and 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 pure water.

[0136] In a second example, the goal of the control is to achieve a restricted or controlled product water pressure. The pressure of the product water in the product water path 371c should generally not exceed a maximum allowable level. The maximum allowable level will, for example, ensure that hardware (such as filters inside or connected to the water purification device or the polishing unit 306) is not damaged. In other words, according to some embodiments, a predetermined higher pressure level corresponds to the pressure tolerance level of at least one filter (such as a sterilization-grade filter) or any other component arranged in the product water path 371c. Thus, according to some embodiments, the predetermined criterion includes maintaining the pressure of the product water in the product water path 371c below a predetermined higher pressure level.

[0137] A typical implementation of the predetermined criterion may, for example, include controlling the control device 305a to attempt to obtain a predetermined flow rate of the 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 higher pressure level. If the pressure reaches the predetermined higher pressure level, the control device 305a will instead control the control device to maintain the pressure at that level even if the flow rate of the product water in the product water path is lower than the predetermined flow rate.

[0138] As discussed above, for a given product water pressure, the throughput will decrease over time. By controlling how much permeate is recycled in the recycle path 375, the product water pressure can be continuously increased to compensate for this behavior. In other words, according to some embodiments, the predetermined product water criterion includes the pressure of the product water in the product water path 371c corresponding to a pressure level. This pressure level in the product water path 371c may, for example, correspond to the expected throughput through the product water port 128 and may thus vary (usually increase) over time.

[0139] In a third example, the goal of the control is to obtain a specific operating point of one or more hardware components of the water purification device 300 (such as the permeate water path 371a or the polished water path 371b ( Figure 6 ), such as the RO device 301 (which is considered to be at least partially included in the permeate water path 371a) or the polishing unit 306). The operating point is, for example, a certain pressure, a certain flow rate, or a certain temperature. Then, an operating point criterion is generally established to keep the operating point within a certain interval.

[0140] For example, a flow sensor 410 is used to measure (or evaluate) the flow rate or pressure of the water in the permeate water path 371a directly downstream of the RO device 306. In principle, any detector in the permeate water path 371a or the polished water path 371b can be used.

[0141] Then, the control device 305a can be used to control the properties of the permeate fluid, such as the pressure in the RO device (especially the transmembrane pressure of the RO membrane) or the flow rate through the polishing device 306.

[0142] In other words, according to some embodiments, the control unit 112 is configured to control the control device 305a based on the properties of the permeate fluid detected by at least one detector (such as the temperature sensor 303 or the flow sensor 410) to control the properties of the permeate water in the permeate water path 371a (such as meeting the operating point criteria of the RO membrane 324 or the polishing device 306) to meet one or more predetermined permeate water criteria.

[0143] In a fourth example, the goal is to maintain the operating temperature of the RO membrane 324 of the water purification device 300 at a constant temperature independent of, for example, the temperature of the inlet water supplied through the inlet port 399 ( Figure 3 ). Since the operating properties of the RO membrane 324 (such as throughput and purification properties) typically depend on the temperature of the RO membrane 324, a constant temperature is generally desired. The constant operating temperature of the RO membrane can be achieved by keeping the temperature of the water flowing through the RO membrane 324 constant. The temperature T_RO of the water flowing through the RO membrane 324 is (at least substantially) the same as the temperature of the purified water directly downstream of the RO device 301 (i.e., upstream of the heater 302) in the permeate water path 371a. This temperature depends on several factors, such as the temperature of the inlet water supplied to the inlet port 399 ( Figure 3 ), the proportion of the hot water recycled in the recirculation path 375, and the temperature of the recirculated water (i.e., the temperature T2 of the purified water after the heater).

[0144] The relationship between the temperature T_RO of the purified water before the heater 302 and the temperature T2 of the purified water after the heater 302 can be calculated using thermodynamics and the following equation:

[0145] P = Q x cpxΔT → T_RO = T2 – P / (Q x cp) (Equation 1)

[0146] In the formula, P is the power (watts) of the heater 302, Q is the flow rate [l / s] through the heater 302 (which is the same as the flow rate 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 flowing through the RO membrane 324). Thus, ΔT is the temperature difference between the water upstream and downstream of the heater 302, i.e., ΔT = T2 – T_RO. In addition, cp is the specific heat capacity of water. The heat capacity or thermal capacity is a measurable physical quantity that is equal to the ratio of the heat added to (or removed from) an object to the resulting change in temperature. The specific heat capacity of water is 4.19 kJ / K. For example, if the flow rate Q through the RO membrane 324 is 210 ml / min (i.e., 0.0035 l / s) and the temperature T2 of the purified water in the permeate water path is 85 °C and the heating power P is 200 W, then the resulting temperature of the RO membrane will be evaluated as:

[0147] T RO = 85 – 200 / (0.0035 x 4190) = 85 – 13.6 °C = 71.4 °C (Equation 2)

[0148] The temperature T2 of the purified water in the permeate water path 371a can be measured using the temperature sensor 303. Thus, the temperature of the RO membrane 324, or more precisely the temperature of the water flowing through the RO membrane 324, can be evaluated by the measured temperature T2 of the purified water in the permeate water path, since the power of the heater 302 and the flow rate Q through the RO membrane 324 are known.

[0149] For example, if a change in the temperature T2 of the purified water in the permeate water path 371a is detected while the power of the heater 302 and the flow rate Q through the heater remain constant, it indicates that the temperature T_RO of the feed water flowing through the RO membrane 324 has changed due to a change in the temperature of the inlet water or the ambient temperature.

[0150] One way to achieve the goal of keeping T_RO constant is to adjust the power P supplied by the heater (i.e., control the temperature of the recirculating water), or to change 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 water path 371a. The flow rate Q of the water flowing through the heater 302 (and the RO membrane 324) can be controlled by changing the pumping frequency of the RO pump 450. However, in some embodiments, it is desirable to use a single pump frequency for each batch of water.

[0151] Another way to achieve the goal of keeping T_RO constant is to change the amount of hot water recycled in the recycle path 375. For example, if more hot water is recycled, the temperature of the water in tank 350 will increase. This will in turn increase the temperature of the feed water supplied through the feed inlet 301a and thus also increase the temperature T_RO of the water flowing through the RO membrane 324.

[0152] As can be seen from the above, the temperature T_RO of the water flowing through the RO membrane 324 can be evaluated using Equation 1 by the measured temperature T2 of the pure water in the permeate path 371a. Then, based on this evaluation, by controlling the control device 305a to adjust the proportion of the permeate stream recycled in the recycle path, the temperature T_RO of the water flowing through the RO membrane 324 can be kept constant. For example, the proportion of the permeate stream recycled in the recycle path can be continuously adjusted so that the evaluated temperature T_RO of the water flowing through the RO membrane 324 remains constant.

[0153] In other words, according to some embodiments, the control unit 112 is configured to control the control device 305a based on the temperature detected by the temperature sensor 303 to control the temperature T_RO of the water flowing through the RO membrane 324. Generally, the control unit 112 is configured to control the control device 305a to control the temperature T_RO such that a predetermined temperature criterion is satisfied. The criterion includes, for example, keeping the temperature T_RO of the water flowing through the RO membrane 324 within a predetermined interval.

[0154] Therefore, the control device 305a can be controlled to keep the temperature of the water after the RO membrane 324 at a predetermined temperature or within a predetermined temperature interval.

[0155] The third example and the fourth example can be used in combination with the above embodiments and the corresponding product water standards, which are intended to control the product fluid properties of the product water in the product water path 371c. Then, different criteria related to pressure, flow rate, and temperature need to be combined (e.g., prioritize and weight) for optimal control.

[0156] In an alternative embodiment, these (third and fourth) embodiments are independent of the above embodiments. Then, the control unit 112 may then not be configured (at least not simultaneously) to control the control device 305a to control the product fluid properties of the product water in the product water path 371c to meet one or more predetermined product water standards, but instead be configured to control only the control device 305a based on the temperature detected by the temperature sensor 303 to control the temperature of the water flowing through the RO membrane 324.

[0157] 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 property detected by at least one detector (e.g., pressure sensor 308 and / or flow sensor 309). For example, to minimize the risk of exceeding a predetermined higher pressure level, the control unit 112 may be configured to trigger an alarm if the pressure measured by the pressure sensor exceeds the predetermined higher pressure level.

[0158] Alternatively, an alarm may be triggered in response to a significant or sudden pressure drop or the like (which would serve as an indication of a malfunction). For example, breakthrough in a filter such as a sterilization-grade filter may cause a pressure drop and thus a reduced pressure and increased flow rate of the product water in the product water path 371c. Since those events do not match, the control unit 112 may issue an alarm in such a case.

[0159] In another example, a leak in the system between the water purification device 300 and the sterilization-grade filters 70a, 70b will also result in a pressure drop of the product water in the product water path 371c. The leak would also be a serious error for which an alarm should be triggered.

[0160] In other words, according to some embodiments, the control unit 112 is configured to activate an alarm function in response to a change in the pressure measured by the pressure sensor 308 and / or a change in the flow rate measured by the flow sensor 309.

[0161] Figure 4b Shows the function of the control unit 112 of the water purification device 300 according to an example embodiment. In this example, the control unit includes a cascade control arrangement that includes a flow rate controller 112a and a pressure controller 112b. In a cascade control arrangement, there are two (or more) controllers, where the output of one controller drives the set point of the other controller.

[0162] In this example, the flow rate controller 112a drives the set point of the pressure controller 112b to obtain a predetermined flow rate of the product water in the product water path 371c. In other words, based on the flow rate of the product water in the product water path 371c measured by the flow sensor 309 and a reference flow rate $ ％&' (e.g., 200 ml / min), the flow rate controller 112a generates first control data ( ) to the pressure controller 112b.

[0163] The pressure controller 112b in turn drives the control device 305a to match the flow rate to the set point required by the flow rate controller 112a as long as the pressure does not exceed a preset pressure level (e.g., 300 kPa). In other words, the pressure controller 112b is based on the pressure of the product water in the product water path 301c measured by the pressure sensor 308 and the first control data () to generate second control data ( * . The pressure controller 112b then uses the second control data ( * to control the control device 305a.

[0164] The controller that drives the setpoint (the flow rate controller 112a in the above example) is referred to as the main controller, external controller, or master controller. The controller that receives the setpoint (the pressure controller 112b in the above example) is referred to as the auxiliary controller, internal controller, or slave controller. The control loop frequency of the internal loop can typically be higher than that of the external loop. For example, the control loop frequency of the pressure controller 112b is 10 Hz.

[0165] Now, a corresponding method for controlling at least one fluid property in the water purification device 300 for producing purified water will be described with reference to Figure 5 the flowchart of and exemplary embodiments of other figures.

[0166] The method is typically executed in the control unit 112 of the water purification device 300. The method can be implemented as program code and stored in the memory 1123 in the control unit 112. Therefore, the steps of the method can be defined in a computer program, which includes instructions that, when the program is executed by a computer (such as the control unit 112), cause the computer to execute the method. Therefore, the steps of the method can also be defined in a computer-readable medium, such as a removable memory, such as a USB memory stick. Then, the computer-readable medium includes instructions that, when executed by a computer, cause the computer to execute the method.

[0167] Typically, the method is executed when the water purification device is in the state RUN and the water purification device supplies product water to, for example, a dialysis machine. However, it must be understood that when no product water is being delivered but instead recycled in an additional recirculation path 381 as described in Figure 6 , the proposed method can also be executed in the state CONNECT or IDLE.

[0168] The method includes detecting S1 at least one fluid property of the purified water in the purified water path 371.

[0169] According to some embodiments, detecting S1 includes detecting at least one product fluid property of the product water in the product water path 371c of the purified water path 371. As described above ( Figure 4a) The product water path 371c is arranged downstream of the recirculation path 375. This step indicates that the product fluid properties are measured, such as the pressure and flow rate of the product water in the product water path. Typically, the corresponding sensors 308, 309 generate sensor data, and the sensor data is provided to the control unit 112 that executes the method.

[0170] The method further includes: adjusting the flow rate of the water in the recirculation path 375 based on at least one detected fluid property to meet one or more predetermined criteria for the purified water in the purified water path 371.

[0171] According to some embodiments, adjusting S2 includes: adjusting the flow rate of the water in the recirculation path 375 based on at least one detected product fluid property to meet one or more predetermined product water criteria for the product water in the product water path 371c. In other words, to control certain product fluid properties, the flow rate of the water in the recirculation path 375 is adjusted.

[0172] Alternatively, adjusting S2 includes: adjusting the flow rate of the water in the recirculation path 375 based on at least one detected product fluid property to meet one or more predetermined permeate water criteria for the permeate water in the permeate water path 371a. An example of a permeate water criterion is that the permeate water has a specific pressure or temperature.

[0173] For example, the flow rate of the water in the recirculation path 375 is adjusted such 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 property includes the flow rate of the product water in the product water path 371c, and then 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.

[0174] In another example, the flow rate of the water in the recirculation path 375 is adjusted such that the pressure of the product water in the product water path 371c does not exceed a threshold. In other words, according to some embodiments, at least one product fluid property includes the pressure of the product water in the product water path 371c. Then the predetermined product water criterion includes that the pressure of the product water in the product water path 371c remains below a predetermined higher pressure level.

[0175] Detection S1 and regulation S2 are typically continuously performed in the RUN state. Thus, each change detected by at least one detector, such as pressure sensor 308 and flow sensor 309, can trigger regulation S2. In other words, the method includes continuously performing detection S1 and regulation S2 while the water purification device 300 produces pure water. The predetermined higher pressure level corresponds, for example, to the pressure tolerance level of at least one filter arranged to filter the product water flowing through the product water path 371c, or to the pressure tolerance level of any other component arranged in the product water path 371c or arranged at a predetermined distance from the product water path 371c.

[0176] According to some embodiments, the method includes activating the S3 alarm function in response to a change in at least one product fluid property. In other words, if the detection shows a certain change, for example, as exemplified above in the associated Figure 4a shown, a sudden increase or decrease in pressure, which can be considered an indication of a potential error. In such a case, the alarm function can be triggered, which sends an alarm to the user regarding the potential error. The alarm can be a sound, a flashing light, or a text message sent or displayed to the user.

[0177] In some cases, it may be desirable to produce product water having a specific temperature. The temperature is required, for example, in a dialysis machine, where the water purification device 300 is required to deliver pure water to the dialysis machine. Then, the temperature of the product water can be controlled accordingly. Thus, according to some embodiments, the method includes controlling S4 the temperature of the product water flowing in the product water path 371c. This can be done by heating using the heater 302. The temperature can actually be set to any temperature, but the range can be limited to 20°C to 35°C.

[0178] If the flow rate of the product water is continuously detected, it is also possible to calculate how much water has passed through the product water path 371c, since this amount will correspond to the overall flow rate. According to some embodiments, the control includes: evaluating S5 the amount of product water produced during a production period based on the duration of the production period and the corresponding flow rate of the pure water detected during the production period. The production period will typically correspond to the time from when production starts until production ends (or if production is ongoing, i.e., production has not ended, until the current time).

[0179] In a second case, i.e., when production is ongoing, when a desired amount of product water has been produced, a predetermined action such as an alarm or a notification can be triggered. The desired amount can be specified, for example, by the user and input via the user interface. In other words, according to some embodiments, the method includes triggering S6 a predetermined action when the amount reaches a certain production volume. The action can be to stop production, notify the attached dialysis machine, or trigger an alarm.

[0180] According to some embodiments, to produce a predetermined amount of water, control includes controlling the fluid properties of the purified water through the product water port 128 to obtain a predetermined flow rate during a predetermined time period. The predetermined flow rate is, for example, between 0.5 liters and 400 liters. The predetermined amount can, for example, correspond to the volume required for one dialysis treatment or several treatments.

[0181] As described above, it may also be desirable to keep the operating temperature of the RO membrane 324 relatively constant. Thus, according to some embodiments, the method includes:

[0182] Measuring the temperature of the water disposed downstream of the heater 302 in the purified water path 371 in the purified water path. Then, the adjustment S2 includes: based on the temperature detected by the temperature sensor 303, 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. As discussed above, in some embodiments, the adjustment may be performed in this manner in combination with or independently of other embodiments described herein.

[0183] Figure 6 An exemplary implementation of the water purification device 300 according to some embodiments is shown in more detail. In other embodiments, the water purification device 300 may include fewer or more components or modules.

[0184] Figure 6 The water purification device 300 receives water from a water source 398 ( Figure 3 ) that is a continuous source of suitable drinking water or potable water, such as from a patient's home. In various embodiments, the water purification device 300 may be installed in a room where the water source 398 can be accessed to provide WFPD to the recirculator 20 as discussed herein. Optionally, the water is filtered using a particulate pre-filter 334 to remove dirt and sediment before being delivered to the water purification device 300. The water enters the water purification device 300 via the water inlet port 333. As discussed above, the water purification device 300 includes a pretreatment module 160, an RO module 170, and a post-treatment module 180. The pretreatment module 160 includes a particulate filter and an activated carbon filter (i.e., an activated carbon bed) to further remove contaminants and impurities. The particulate 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 inflow of the feed water under the control of the control unit 112. The constant flow device 330 provides a constant flow to the tank 350 provided that the water pressure is above the minimum pressure of the inlet valve 332.

[0185] In addition, the pretreatment module 160 includes, downstream of the filter cartridge 331, a sampling valve 329 having a sampling port outlet 329a, a tank valve 328, a pretreatment conductivity sensor 327, and a feed water temperature sensor 326. The sampling port outlet 329a allows sampling from the feed water to, for example, test the chlorine level. The tank valve 328 controls the flow of filtered feed 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 feed water to be filtered 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 port 333 and terminates in 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. As is known in the art, water softening in the pretreatment module 160 can alternatively or additionally be achieved using lime softening, ion exchange resins, or scale inhibitors such as polyphosphates. It should be understood that in some embodiments, the filter cartridge 331 is not required and may be absent.

[0186] As described above, the RO module 170 includes a tank 350, an RO pump 450, and an RO device 301. The RO device 301 has been described in detail, and reference is made to that description for further illustration. Filtered (or unfiltered) feed water enters the tank 350, for example, from the upper part of the tank 350. The feed water accumulates in the tank 350 and is pumped by the RO pump 450 to the supply inlet 301a of the RO device 301 (see Figure 4a ). Figures 5 - 6 )

[0187] A vacancy switch 350a, a low level switch 350b, and a high level switch 350c are provided in the tank 350 to detect its water level, while a computer program running 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. The inlet valve 332 and the tank valve 328 are open during the filling of the tank 350 and close when the water level in the tank 350 activates its high level switch 350c connected to the control unit 112. When the water level drops below the low level switch 350b in the tank 350, the inlet valve 332 opens again, thus tripping the low level switch connected to the control unit 112. If the water level in the tank 350 rises too high, the excess water is discharged via the tank vent line 325 and the tank vent 335 (overflow connection) to, for example, the tray 420 or the drainer 339. The tank vent 335 can be accessed from outside the water purification device 300. The tank vent 335 can be closed, for example, during the transportation of the water purification device 300, so as to prevent any water in the tank 350 from flowing to the tray 420 and causing water to flow to the outside of the water purification device 300.

[0188] The control unit 112 is configured to stop the RO pump 450 from pumping if the air or critical low water level is detected by the air vacancy switch 350a in the tank 350. The RO pump 450 is configured to provide the water flow rate and pressure required for the reverse osmosis process occurring at the RO device 301. As described previously, for example, with reference to Figure 4a described, the RO device 301 filters water to provide pure water at its permeate water outlet 301b. The retentate water leaving the RO device 301 at the retentate outlet 301c can be supplied back into the RO pump 450 to conserve water consumption or alternatively be pumped to the ejector 339.

[0189] The pure water leaving the RO device 301 is transported in the pure water path 371 inside the water purification device 300 before being output through the product water port 128. The pure water path 371 includes (as Figure 4a shown) a permeate water path 371a, a polished water path 371b, and a product water path 371c. The polishing device 306 can be bypassed via a bypass path 371d. The bypass path 371d is connected to the water path upstream of the polishing device 306 (here an EDI device) and to the water path downstream of the EDI device. The pure water leaving the RO device 301 passes through the flow sensor 410, the heater 302, and the permeate temperature sensor 303 included in the permeate water path 371a. The flow sensor 410 monitors the flow rate of the pure water leaving the RO device 301. Under the control of the control unit 112, the heater 302 heats the pure water leaving the RO device 301. The permeate temperature sensor 303 monitors the temperature of the pure water leaving the RO device 301 directly downstream of the heater 302. Another conductivity sensor 304 monitors the conductivity of the pure water leaving the RO device 301.

[0190] Downstream of the heater 302, the permeate temperature sensor 303, and the conductivity sensor 304, the pure water enters the post-treatment module 180 via the polished water path 371b. The post-treatment module 180 includes a polishing device 306. The three-way valve 305c is arranged to be controlled by the control unit 112 to selectively direct the pure water flow to the polishing device 306 or to the bypass path 371d to bypass the polishing device 306. The polishing device 306 is configured to produce product water. The product channel valve 307 regulates the flow rate of the product water in the product water path 371c from the polishing device 306. The concentrate water path 377c is arranged to return the fluid from the polishing device 306 to the tank 350.

[0191] Product water is delivered to product water port 128 and further to the water conduit 64 (64a, 64b) of the disposable device 40 connected thereto for transportation to the point of care. The disposable device 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 omitted, or the number of filters is less than or greater than two.

[0192] The discharge port 118 defines a first discharge path 384 to the discharger 339. To allow water such as used PD fluid to pass from the discharge port 118 to the discharger 339, the discharge conduit 56 of the disposable device 40 is connected to the discharge port 118. The first discharge path 384 here represents a part of the recirculator discharge path located inside the water purification device 300. The first discharge path 384 includes a conductivity sensor 336, a discharge path temperature sensor 315, and a discharge conduit valve 341. The conductivity sensor 336 is configured to measure the conductivity of the water in the discharge path. The temperature sensor 315 is arranged to measure the temperature of the water in the first discharge path 384. Under the control of the control unit 112, the discharge conduit valve 341 is arranged to regulate the flow rate in the first discharge path 384 via the conductivity sensor 336. The first discharge path 384 further includes a bypass path 384a which is arranged to bypass the conductivity sensor 336, the discharge path temperature sensor 315, and the discharge conduit valve 341. The bypass path 384a includes a valve 340. The valve 340 is arranged to regulate the flow rate through the bypass path 384a.

[0193] As Figure 4a shown in, the control device 305a is configured to control the flow rate of the purified water in the recirculation path 375 which is arranged from a point downstream of the heater 302, the permeate temperature sensor 303, and the additional conductivity sensor 304 to the return 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 fine treatment device 306. As Figure 4a shown in, the flow sensor 309 is arranged to monitor the flow rate of the product water downstream of the fine treatment device 306. The pressure and flow rate of the product water are provided to the control unit 112. The control unit 112 is configured to control the operation of the control device 305a. More specifically, 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 unit is configured to regulate the flow rate of the water in the recirculation path 375 based on the pressure and flow rate of the product water. The control device 305a is, for example, an electric flow control valve which is configured to precisely regulate the flow rate of the water in the recirculation path 375.

[0194] Under the control of the control unit 112, the product water valve 305d is arranged to control the flow of the produced product into the product water port 128 or to return it to the tank 350 via an additional recirculation path 381. The drain 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 gas collection chamber 319. The product water conductivity sensor 312 is arranged to monitor the conductivity of the product water upstream of the gas collection chamber 319. The product water temperature sensor 313 is configured to monitor the temperature of the product water upstream of the gas collection chamber 319.

[0195] In operation, a portion of the reject water leaving the RO device 301 passes through the auxiliary constant flow device 318 via the fluid path 385a, and the auxiliary constant flow device 318 provides a stable reject water flow to the three-way valve 305b (e.g., a three-way solenoid valve) under the control of the control unit 112. The remaining portion of the reject water returns to the RO pump 450 via the valve 320 (e.g., a manual needle valve) in the first reject path 385b. The three-way valve 305b is configured to selectively transfer the reject water to the ejector 339 via the second discharge path 388 or return it to the tank 350, or return the reject water to the tank 350 via the second reject path 389. The bypass path 385f is arranged to bypass the auxiliary constant flow device 318. The flow control device 321 is arranged to control the flow rate in the bypass path 385f under the control of the control device 112.

[0196] When the treatment is completed, the water purification device 300 sets itself to be ready to disconnect from the disposable tubing device 40 (e.g., in response to a message received through the circulator 20), closes the lids (not shown) that externally cover the product water port 128 and the discharge port 118, and at the same time connects the product water port 128 and the discharge port 118 via the path 401a so that the heated fluid can flow out of the product water port 128 and into the discharge port 118 and further flow to the ejector 339 via the first discharge path 384.

[0197] In some embodiments, all the gauges and sensors described in connection with Figure 6 the water purification device 300 therein are configured to send their corresponding signals to the control unit 112.

[0198] To protect the components of the water purification device 300 as much as possible, improve reliability, and prevent bacterial growth, the water purification device 300 provides hardware and programs for cleaning.

[0199] The water purification device 300 further includes a container 392 that contains a microbial growth inhibitor. The microbial growth inhibitor is used to prepare a cleaning solution, such as introducing citric acid into the water path in some embodiments. As shown, the container 392 is in fluid communication with the inlet 392a of the water purification device 300. In Figure 6 , the pipeline 382 connects the container 392 to the water path of the water purification device 300. Alternatively, the container 392 can be connected via a pipeline (not shown) that directly leads to the disposable cartridge 42 operating with the circulation machine 20, or connected to the water pipeline 64, or connected to the discharge pipeline 56.

[0200] The reagent for inhibiting microbial growth in the container 392 can be a suitable physiologically safe acid, such as citric acid, citrate, lactic acid, acetic acid, or hydrochloric acid (or a combination thereof). In one embodiment, the container 392 contains citric acid, citrate, or a derivative thereof. It should be noted that the container 392 can also include additives provided together with the acid, such as with citric acid. The chemical inlet 392a is located, for example, at the front of the water purification device 300. There is a sensor (not shown, such as an optical sensor) arranged to sense when the container 392 is connected to the chemical inlet 392a. Under the control of the control unit 112, the three-way valve 317 at the chemical inlet 392a is arranged to open towards the second pump and the tank 350 that is the chemical suction pump 316. The chemical suction pump 316 is arranged to supply the disinfection solution into the tank 350. The optical sensor is arranged to detect whether the source of the cleaning or disinfection solution is connected or disconnected. If / when the container 392 is removed or not detected by the optical sensor, the chemical suction pump 316 stops or is not activated and the three-way valve 317 closes towards the chemical inlet 392a. Under the control of the control unit 112, the three-way valve 317 can also be used to recycle water and disinfectant from the tank 350 and recycle it back to the tank 350 during the chemical disinfection, cleaning, and / or rinsing phases. The chemical suction pump 316 and the valve 310 are arranged in a path 379 that is in fluid connection with the three-way valve 317 and the product water path 371c. The valve 310 is arranged to control the flow rate in the path 379.

[0201] In a more detailed example of the disinfection phase, when chemical disinfection is initiated, the liquid level in tank 350 is adjusted to a level just above the low level switch 350b. The control unit 112 causes the RO pump 450 to start and run until the air space switch 350a indicates the presence of air. Then, the RO pump 450 stops and the inlet valve 332 opens. The inlet valve 332 remains open until the air space switch 350a indicates water. Then, the chemical suction pump 316 runs until a preset amount of chemical solution is inserted into tank 350. When the liquid level in tank 350 reaches a predetermined level, the three-way valve 317 opens to the ejector 339. The RO pump 450 circulates water in the flow path during the chemical suction phase and can operate in both directions to create turbulence and increase the disinfection time and contact. At the end of the suction phase, the retention bypass valve 321 opens and the three-way valve 305b is actuated to open a second discharge path 388 to the ejector 339 and drain the water level in tank 350 to its low level at the low level switch 350b.

[0202] Except for the filter package 331, the described pretreatment module 160, RO module 170, and post-treatment module 180 are enclosed inside a single water purification cabinet 110a, where the filter package 331 is removably arranged (e.g., hinged) on the outside of the single water purification cabinet 110a. Then, the filter package 331 can be replaced when it is used up. In an alternative embodiment, the modules can be arranged in separate units. As described above, purified water is sent from the water purification device 300 to the disposable device 40 via the water pipeline 64. Refer Figure 1 , the water pipeline 64 supplies purified water to the water port 282 of the cartridge 42 of the disposable device 40. In one embodiment, the water pipeline 64 is a flexible tube, whose first end is connected to the product water port 128 of the water purification device 300 and whose second end is connected to the water port 282 of the circulator 20. The water pipeline 64 can be at least 2 meters long and, in one embodiment, longer than 4 meters. The water pipeline 64 allows the water purification device 300 to be installed in a room with an available water source, while the circulator 20 is located in a different room where the patient is located (e.g., sleeping). The water pipeline 64 can thus be the length required to connect the water purification device 300 to the circulator 20.

[0203] Figure 6 Also shown is that the disposable device 40 includes a discharge pipeline 56, which is configured and arranged to direct water such as used dialysis fluid to the ejector 339 of the water purification device 300. The discharge pipeline 56 is, for example, a tube, whose first end is connected to the cartridge 42 of the circulator 20 and includes a discharge pipeline connector 58( Figure 1) Its second end is connected to the discharge port 118 of the water purification device 300. The discharge pipe 56 can alternatively be a flexible pipe, which can be more than 2 meters long and, in some embodiments, longer than 4 meters. The discharge pipe 56 can be the length required to connect the water purification device 300 and the circulation machine 20. In the illustrated embodiment, the water pipe 64 and the discharge pipe 56 extend in parallel using a double - lumen pipe. It can also be that the water purification device 300 and the circulation machine 20 are placed close to each other such that the same two - pipe water path including the water pipe 64 and the discharge pipe 56 can be, for example, less than 0.5 meters. Additionally, although the double - lumen water pipe 64 and discharge pipe 56 are shown, the water pipe 64 and the discharge pipe 56 can be separate.

[0204] The water tray 420 is located below the water purification device 300. The liquid sensor 370 is arranged at the bottom of the water tray 420 to detect any leakage from the water purification device 300.

[0205] The present disclosure is not limited to the above - preferred embodiments. Various alternatives, modifications, and equivalents can be used. Therefore, the above embodiments should not be regarded as limiting the scope of the present disclosure, which is defined by the appended claims.

Claims

1. A water purification device (300), characterized in that, The water purification device includes: A reverse osmosis device (301) configured to produce purified water, the reverse osmosis device (301) including a supply inlet (301a) positioned to receive feed water and a purified water outlet (301b); A reverse osmosis pump (450) configured to pump the feed water to the supply inlet (301a); 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), A purified water path (371) configured to transport the purified water from the purified water outlet (301b) to a destination, wherein the purified water path (371) includes: (i) a permeate water path (371a) positioned upstream of the recirculation path (375), and (ii) a product water path (371c) positioned downstream of the recirculation path (375) to transport the product water to the destination, wherein the permeate water path (371a) divides into the recirculation path (375) and the product water path (371c) at the first point; A flow sensor (410) configured to detect the flow rate of the purified water in the permeate water path (371a); and A control unit (112) configured to control the reverse osmosis pump (450) to a specific pump rate, the specific pump rate corresponding to a specific flow rate of the purified water through the permeate water path (371a).

2. The water purification device (300) according to claim 1, wherein, The flow sensor (410) is a first flow sensor, and wherein the water purification device (300) includes a second flow sensor (309) configured to detect the flow rate of the product water in the product water path (371c).

3. The water purification device (300) according to claim 1 or 2, further comprising a heater (302), wherein the heater (302) is positioned downstream of the reverse osmosis device (301) to heat the purified water flowing in the purified water path (371).

4. The water purification device (300) according to claim 3, wherein, The water purification device includes a temperature sensor (303) positioned to measure the temperature of the purified water downstream of the heater (302), and wherein the control unit (112) is configured 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).

5. The water purification device (300) according to claim 1 or 2, wherein, The water purification device includes at least one pressure sensor (308) positioned and arranged to detect the pressure of the purified water in the purified water path (371), and wherein the control unit (112) is configured to use the detected pressure to control the pressure of the purified water so as to (i) stay below a predetermined upper pressure level, or (ii) attempt to achieve a predetermined pressure.

6. The water purification device (300) according to claim 1 or 2 further comprises a tank (350) configured to receive water from an external water source and supply feed water to the supply inlet (301a) of the reverse osmosis device (301).

7. The water purification device (300) according to claim 6, wherein, Water from the external water source flows through a filter pack (331) before reaching the tank (350).

8. The water purification device (300) according to claim 6, wherein, A second point upstream of the reverse osmosis device (301) for the recirculation path (375) is provided at the tank (350).

9. The water purification device (300) according to claim 6, wherein, The water purification device includes a vent line (325) extending from the upper part of the tank (350).

10. The water purification device (300) according to claim 1 or 2 further comprises a polishing unit (306) positioned downstream of the reverse osmosis device (301) in the purified water path (371).

11. The water purification device (300) according to claim 10, wherein, The permeate water path (371a) is positioned to transport purified water from the purified water outlet (301b) of the reverse osmosis device (301) to the inlet of the polishing unit (306).

12. The water purification device (300) according to claim 10, wherein, The product water path (371c) is positioned and arranged to transport purified water from the outlet of the polishing unit (306) to the destination.

13. The water purification device (300) according to claim 1 or 2, wherein, The water purification device includes a flow control device (305a) positioned along the recirculation path (375).

14. The water purification device (300) according to claim 1 or 2, wherein, The destination includes a product water port (128).

15. The water purification device (300) according to claim 1 or 2, wherein, The water purification device includes: a detector configured to detect the fluid properties in the product water path (371c), and a flow control device (305a) positioned along the recirculation path (375), wherein the control unit (112) is configured to control the flow control device (305a) based on the fluid properties detected by the detector.

16. The water purification device (300) according to claim 15, wherein, The fluid properties include fluid pressure, fluid flow rate, or fluid temperature.

17. A peritoneal dialysis system, characterized in that, The peritoneal dialysis system includes: A water purification device (300) comprising: A reverse osmosis device (301) configured to produce purified water, the reverse osmosis device (301) including a supply inlet (301a) positioned to receive feed water and a purified water outlet (301b); A reverse osmosis pump (450) configured to pump feed water to the supply inlet (301a); 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), A purified water path (371) configured to transport purified water from the purified water outlet (301b) to a destination, wherein the purified water path (371) includes: (i) a permeate water path (371a) positioned upstream of the recirculation path (375), and (ii) a product water path (371c) positioned downstream of the recirculation path (375) to transport product water to the destination, wherein the permeate water path (371a) branches into the recirculation path (375) and the product water path (371c) at the first point; A flow sensor (410) configured to detect the flow rate of pure water in the permeate water path (371a); and A control unit (112) configured to control the reverse osmosis pump (450) to a specific pump rate corresponding to a specific flow rate of pure water through the permeate water path (371a); and A peritoneal dialysis ("PD") cycler positioned and arranged to use PD fluid during PD treatment, the PD fluid being mixed with product water from the water purification device (300).

18. The peritoneal dialysis system according to claim 17, wherein, The destination includes a product water port (128).

19. A method for controlling at least one fluid property in a water purification device, characterized in that, The water purification device (300) includes: a reverse osmosis device (301) configured to produce pure water, and a recirculation path (375) arranged to recirculate a portion of the pure 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 comprising: Arranging the pure water path (371) to include: (i) a permeate water path (371a) positioned upstream of the recirculation path (375), and (ii) a product water path (371c) positioned downstream of the recirculation path (375); Dividing the permeate water path (371a) into the recirculation path (375) and the product water path (371c) at the first point; and Controlling the reverse osmosis pump (450) to a specific pump rate corresponding to a specific flow rate of pure water through the permeate water path (371a).

20. The method according to claim 19, further comprising evaluating 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 pure water detected during the production time period.

21. The method according to claim 19 or 20, further comprising triggering a predetermined action when the amount reaches a predetermined production amount.

22. The method according to claim 19 or 20, wherein The method includes monitoring at least one pressure sensor (308) positioned and arranged to detect the pressure of pure water in the pure water path (371), and using the detected pressure to control the pressure of the pure water so that (i) it stays below a predetermined upper pressure level, or (ii) it attempts to achieve a predetermined pressure.

23. The method according to claim 19 or 20, wherein The method includes monitoring a temperature sensor (303) positioned to detect the temperature of the pure water, and controlling 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).

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