System and method for thermal disinfection of a reverse osmosis system

Abstract

System (120) comprising a reverse osmosis system (100) and a hot cleaning system (103) for thermal disinfection of the reverse osmosis system (100), the reverse osmosis system (100) comprising at least one booster pump (112) and a membrane module (114), wherein the reverse osmosis system (100) is hydraulically connected to the hot cleaning system (103) via an inlet line (101), and wherein a return line (106), into which a solenoid valve (105) is connected, leads from the hot cleaning system (103) to the reverse osmosis system (100), and wherein the inlet line (101) is hydraulically connected to the return line (106) by a bypass line (102), into which a bypass valve (104) is connected, which completely releases a flow through the bypass line (102) when the pressure in the inlet line (101) is greater than a holding pressure of the bypass valve (104), wherein the reverse osmosis system (100) has a control unit (107) which carries out the following steps: a) opening the solenoid valve (105) and directing heated water from the hot cleaning system (103) through the return line (106) into the reverse osmosis system (100); b) Checking the disinfection status of the reverse osmosis system (100); c) If a disinfection target of the reverse osmosis system (100) stored in the control unit (107) is reached, close the solenoid valve (105).

Description

[0001] The invention relates to a system and a method for thermal disinfection of a reverse osmosis system.

[0002] Reverse osmosis systems must be disinfected as needed or at regular intervals. This type of disinfection can be achieved thermally by hydraulically connecting the reverse osmosis system to a hot cleaning system. The hot cleaning system functions like a flow heater, heating the water supplied to it from the reverse osmosis system and then pumping this heated water back into the reverse osmosis system.

[0003] In known methods for disinfecting a reverse osmosis system, the reverse osmosis system and the hot cleaning system are connected. Each system has a control unit that exchanges basic commands (hot cleaning mode active, hot cleaning system requires permeate, i.e., filtered water, etc.). Since both systems each have a control unit, these commands or requests are evaluated independently, and the corresponding actions are performed.

[0004] The process and success monitoring of thermal disinfection are also carried out independently by both systems, or rather their control units. This means that the disinfection goal or success criteria of a reverse osmosis system may be different from those of a hot cleaning system.

[0005] In the example above, the disinfection target could be a combination of time and a minimum temperature. However, this means that the hot cleaning system is not compatible, or only with considerable effort, with reverse osmosis systems that use an A0 value as a success measure. Furthermore, some form of data transmission must always be available between the reverse osmosis system and the hot cleaning device.

[0006] WO 2022 / 008481 A1 discloses a thermal disinfection system and method for performing a thermal disinfection process for fluid lines of a medical device. The thermal disinfection process comprises the steps of receiving a temperature signal from a temperature sensor, determining a measured temperature value of the fluid within the hydraulic circuit, receiving a pressure signal from a pressure sensor, determining a measured local atmospheric pressure value, and controlling a heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value.

[0007] The invention is based on the object of providing an improved system and method for disinfecting a reverse osmosis system that overcomes the disadvantages of the prior art. In particular, thermal disinfection of the reverse osmosis system should be possible without the two systems having to communicate with each other via signaling.

[0008] With regard to the system, this object is achieved by a system having the features of claim 1. The system comprises a reverse osmosis system and a hot cleaning system, the reverse osmosis system comprising at least one pressure booster pump and a membrane module, wherein the reverse osmosis system is hydraulically connected to the hot cleaning system via an inlet line, and wherein a return line, into which a solenoid valve is connected, leads from the hot cleaning system to the reverse osmosis system, and wherein the inlet line is hydraulically connected to the return line by a bypass line, into which a bypass valve is connected, which completely releases a flow through the bypass line when the pressure in the inlet line is greater than a holding pressure of the bypass valve, wherein the reverse osmosis system has a control unit which performs the following steps: a) Opening the solenoid valve and directing heated water from the hot cleaning system through the return line into the reverse osmosis system; b) Checking the disinfection status of the reverse osmosis system; c) If a disinfection target of the reverse osmosis system stored in the control unit is reached, close the solenoid valve.

[0009] Advantageous embodiments of the invention are the subject of the subclaims.

[0010] The invention is based on the consideration that disinfection targets of the two systems or other components, such as a consumer connected to a ring line, can be defined differently and can also be achieved at different times.

[0011] As has now been recognized, a simultaneously complete and energy-saving disinfection of the reverse osmosis system can be achieved by the reverse osmosis system independently monitoring the achievement of its specified disinfection target and automatically stopping the pumping of water into the hot cleaning system when this target is reached.

[0012] The disinfection status of the reverse osmosis system is advantageously calculated, preferably iteratively, using temperatures repeatedly measured at at least one location in the reverse osmosis system and the duration of the hot cleaning. The temperature is preferably measured at several locations in the reverse osmosis system, in particular at regular intervals between 100 ms and 300 ms, in particular every 200 ms. If the temperature is measured at only one location in the reverse osmosis system, it is preferably measured at the coldest location during the process, so that the successful and complete disinfection of the entire reverse osmosis system can be ensured.

[0013] Advantageously, the holding pressure of the bypass valve is set such that during step a), only a volume flow that is less than or equal to a predetermined volume flow threshold flows through the bypass line. In this way, only a low volume flow is maintained through the bypass line while the reverse osmosis system is disinfected using the heated water. Particularly preferably, no (i.e., the volume flow threshold is zero) or only a minimal volume flow is passed through the bypass line during phase a), and only actively flows through during phase c).

[0014] This has the advantage that water extracted from the ring main is directly replenished via the hydraulic connection, without any communication or action required. Furthermore, no excess energy is required to continue supplying the already disinfected reverse osmosis system with hot water.

[0015] In a preferred embodiment, at least one ring line with at least one connected consumer is hydraulically connected to the hot cleaning system, with heated water being pumped through the ring line and supplied to the respective consumer. In this way, the thermal disinfection of consumers can take place at least partially simultaneously with the thermal disinfection of the reverse osmosis system.

[0016] The disinfection target stored in the reverse osmosis system's control unit preferably uses an A0 value as a success control according to DIN EN 15883. The A0 value is defined by the usual definition: 1 A0 = 1 second exposure time at 80°C. It serves as a benchmark for the destruction of microorganisms in moist heat processes. An A0 value is preferably specified for the disinfection target, which in the case of reverse osmosis systems is 600 or higher.

[0017] The A0 value is calculated iteratively by summing products from the respective time step and a power of ten, where the exponent is given by the difference between the currently measured temperature and 80°C divided by a z-value. The z-value is fixed for the respective microorganism and in this case is 10°C.

[0018] An A0 value of at least 600 required for reverse osmosis systems can be achieved, for example, by disinfection at a temperature of 80°C for 10 minutes or by disinfection for 100 minutes at 70°C.

[0019] In a first preferred embodiment, the bypass valve is designed as an overflow valve. The holding pressure of the bypass valve is configured such that it allows permeate flow through the bypass line when the pressure in the supply line for hot cleaning is greater than the holding pressure of the overflow valve. In this way, circulation of the permeate is enabled when the solenoid valve in the return line is closed after completion of thermal disinfection and upon reaching the predetermined disinfection target of the reverse osmosis system. The overflow valve preferably has a spring by which the holding pressure is adjusted. The spring is preferably designed such that it loses spring force as the temperature rises. This ensures an additional reduction in the pump speed of the pressure booster pump of the reverse osmosis system.

[0020] In another preferred embodiment, the bypass valve is designed as a solenoid valve. It is signal-connected to the control unit and closed during thermal disinfection of the reverse osmosis system. It is opened by the control unit when the specified disinfection target of the reverse osmosis system has been reached after the thermal disinfection has been completed.

[0021] With regard to the method, the above-mentioned object is achieved according to the invention by the steps of specifying a disinfection target of the reverse osmosis system, checking the disinfection status of the reverse osmosis system, and when the specified disinfection target of the reverse osmosis system is reached, stopping the pumping of heated water through the return line and pumping the heated water from the supply line via a bypass line into the return line.

[0022] Checking the disinfection status of the reverse osmosis system is preferably carried out iteratively or at regular intervals. The disinfection target is achieved when the disinfection status of the reverse osmosis system corresponds to the defined disinfection target.

[0023] Advantageously, during the conveyance of heated water through the return line through the bypass line, only a volume flow of heated water is conveyed which is lower than a predetermined volume flow threshold value or no volume flow at all.

[0024] In a preferred embodiment, heated water is pumped through a ring pipeline connected to the hot cleaning system. In this way, in addition to the ring pipeline, consumers connected to the ring pipeline at outlets can also be thermally disinfected.

[0025] Advantageously, heated water is provided to at least one consumer connected to the ring line, wherein the provided flow rate of liquid is replenished by a pressure booster pump of the reverse osmosis system.

[0026] The disinfection target of the reverse osmosis system is preferably defined using the A0 value.

[0027] The advantages of the invention lie in the fact that during thermal disinfection of the reverse osmosis system, the two systems require little or no data transmission. In a sense, an economy circuit is provided for the thermal disinfection of a reverse osmosis system, since only the disinfection target of the reverse osmosis system is taken into account, and the reverse osmosis system only needs to be rinsed with heated water until this target is reached. Furthermore, after the reverse osmosis system has been disinfected, consumers can continue to be supplied with heated water. This is energetically advantageous, since heat loss (via the reverse osmosis system) is lower, thus making the overall process more efficient. Different disinfection targets can be achieved for the ring line and the reverse osmosis system.

[0028] However, the process can also be used if the two systems are connected and exchange data. This data exchange can be used for status messages (start of hot cleaning, achievement of the disinfection target, etc.) as well as for exchanging parameter sets and operating data.

[0029] An embodiment of the invention is explained in more detail below with reference to a drawing. In this highly schematic representation: Fig. 1 a system consisting of a reverse osmosis system and a hot cleaning system; Fig. 2 an exemplary diagram of a pump speed as a function of time; and Fig. 3 a flow diagram of a method for thermal disinfection of a reverse osmosis system in a preferred embodiment.

[0030] Identical parts are provided with the same reference numerals in all figures.

[0031] In Fig. Figure 1 shows a preferred embodiment of a reverse osmosis system 100 and a hot cleaning system 103. The reverse osmosis system 100 is hydraulically connected to the downstream hot cleaning system 103 via a supply line 101. The reverse osmosis system 100 and the hot cleaning system 103 form a system 120.

[0032] A hydraulic return line 106 leads from the hot cleaning system 103 to the reverse osmosis system 100. A solenoid valve 105 is connected to the return line 106. The hot cleaning system 103 acts like a continuous flow heater, which in Fig. 1 is represented by a dashed line 110. The liquid which is conveyed from the reverse osmosis system 100 through the inlet line 101 into the hot cleaning system 103 is heated therein before being conveyed through the return line 106 into the reverse osmosis system 100.

[0033] The reverse osmosis system 100 has a booster pump 112 and at least one membrane module 114, which divides the liquid stream to be filtered into permeate and concentrate in a known manner.

[0034] The reverse osmosis system 100 has a control unit 107 in which a desired or predefined disinfection target is stored. The disinfection target of the reverse osmosis system stored in the control unit 107 of the reverse osmosis system preferably uses an A0 value as a success control.

[0035] The two lines 101, 106 are hydraulically connected to each other via a bypass line 102, into which an overflow valve 104 is connected. Permeate only flows through the bypass line 102 when the pressure in the supply line 101 to the hot cleaning system 103 is greater than the holding pressure of the overflow valve 104. This can be the case, for example, when the control unit 107 closes the solenoid valve 105 in the return line 106 to the reverse osmosis system 100.

[0036] Optionally, a ring line 108 with a number of consumers 109 (e.g., dialysis machines) can be connected to the hot cleaning system 103. These consumers 109 can draw hot water from the ring line 108 to disinfect themselves thermally or chemothermically.

[0037] The hot cleaning system 103 has its own pump, which circulates the water in the ring line 108. For the duration of the active hot cleaning of the reverse osmosis system 100, the solenoid valve 105 is open. The holding pressure of the overflow valve 104 is set such that no or only a very low volume flow flows through the bypass line 102. This supplies the reverse osmosis system 100 with hot water from the hot cleaning system 103 via the return line 106. As soon as the reverse osmosis system 100 has reached its disinfection target, the control unit 107 closes the solenoid valve 105. As a result, no hot water is fed back into the reverse osmosis system 100. The hot cleaning system 103 can thus save heating energy because the reverse osmosis system 100 no longer consumes hot water.

[0038] If, in the meantime, at least one consumer 109 draws water from the connected ring line 108, the volume is automatically replenished via the reverse osmosis system 100 through the supply line 101. This occurs due to the changing pressure conditions caused by the missing volume within the hot cleaning system 103 and the connected ring line 108. Thus, the reverse osmosis system 100 also cools down over time and requires less active cooling at a later time. This is due, on the one hand, to the decoupling of the hot water supply from the hot cleaning system 103 and, on the other hand, to the replacement of the volume drawn by consumer 109 with colder process inlet water / soft water.

[0039] If the reverse osmosis system 100 has controlled actuators, such as booster pumps and / or circulation pumps, energy consumption can also be reduced, as the hot water no longer needs to be circulated within the reverse osmosis system 100 and the permeate production only needs to replace the consumed volume. This ensures a reduction in the pump speed, as is the case, for example, in Fig. 2 is shown.

[0040] In the Fig. In the diagram shown in Figure 2, the time in seconds is shown on an x-axis 200 and the pump speed in revolutions per minute of a regulated booster pump 112 of the reverse osmosis system 100 is shown on a y-axis 202. A curve 204 represents the pump speed. In a first time period 206, during which heated water is pumped through the return line 106 into the reverse osmosis system 100, the pump speed slowly decreases over time until it is reduced by approximately half at the beginning of a second time period 208, in which the pumping of heated water into the reverse osmosis system 100 is terminated, in order to maintain only a basic circulation in the reverse osmosis system 100. The temporal decrease in the pump speed during the active hot cleaning in the first time period 206 is caused by the decreasing resistance of the at least one membrane module 114.

[0041] A particularly advantageous feature of this design is the decreasing holding pressure of the overflow valve 104 as the temperature rises. This is because the holding pressure of the overflow valve 104 is adjusted by a spring, which loses spring force as the temperature rises. This further reduces the pump speed of the reverse osmosis system 100.

[0042] Due to the illustrated structure and the described method, no communication is necessary between the reverse osmosis system 100, the hot cleaning system 103, and the consumer 109 to perform a hot cleaning. Likewise, different disinfection targets can be achieved between the reverse osmosis system 100 and the remaining system components (103, 108, 109), as long as the disinfection target of the reverse osmosis system 100 is reached earlier.

[0043] In Fig.Figure 3 shows a method for thermal disinfection of a reverse osmosis system 100 as a flowchart. In a first method step 300, a disinfection target for the reverse osmosis system 100 is specified, which in this case uses an A0 value as a success control. In a subsequent method step 302, water is pumped from the reverse osmosis system 100 through a supply line 101 into a hot cleaning system 103, where it is heated. The heated water from the hot cleaning system 103 is pumped in parallel through a return line 106 into the reverse osmosis system 100.

[0044] A decision 304 checks whether the specified disinfection target has already been achieved. If this is not the case, the method branches back to method step 302. Otherwise, a method step 306 is executed, in which the pumping of heated water through the return line 106 is terminated and the heated water is pumped from the supply line 101 via a bypass line 102 into the return line 106. List of reference symbols 100 reverse osmosis system 101 Inlet line 102 Bypass line 103 Hot cleaning system 104 Overflow valve 105 Solenoid valve 106 Return line 107 Control unit 108 ring line 109 consumers 110 Line 112 Booster pump 114 Membrane module 120 systems 200 x-axis 202 y-axis 204 Curve 206 first chronological section 208 second chronological section 300 process steps 302 Process step 304 Decision 306 Process step QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2022 / 008481 A1

[0006]

Claims

[1] System (120) comprising a reverse osmosis system (100) and a hot cleaning system (103) for thermal disinfection of the reverse osmosis system (100), the reverse osmosis system (100) comprising at least one booster pump (112) and a membrane module (114), wherein the reverse osmosis system (100) is hydraulically connected to the hot cleaning system (103) via an inlet line (101), and wherein a return line (106), into which a solenoid valve (105) is connected, leads from the hot cleaning system (103) to the reverse osmosis system (100), and wherein the inlet line (101) is hydraulically connected to the return line (106) by a bypass line (102), into which a bypass valve (104) is connected, which completely releases a flow through the bypass line (102) when the pressure in the inlet line (101) is greater than a holding pressure of the bypass valve (104), characterized by , that the reverse osmosis system (100) has a control unit (107) which carries out the following steps: a) opening the solenoid valve (105) and directing heated water from the hot cleaning system (103) through the return line (106) into the reverse osmosis system (100); b) Checking the disinfection status of the reverse osmosis system (100); c) If a disinfection target of the reverse osmosis system (100) stored in the control unit (107) is reached, close the solenoid valve (105). [2] System (120) according to claim 1, wherein the holding pressure of the bypass valve (104) is set such that during step a) only a volume flow that is less than or equal to a predetermined volume flow threshold value flows through the bypass line (102). [3] System (120) according to claim 1 or 2, wherein a ring line (108) with at least one consumer (109) connected thereto is hydraulically connected to the hot cleaning system (103), and wherein hot water is conveyed through the ring line (108) and is made available to the respective consumer (109). [4] System (120) according to one of claims 1 to 3, wherein the disinfection target of the reverse osmosis system (100) stored in the control unit (107) uses an A0 value as a success control. [5] System (120) according to one of claims 1 to 4, wherein the bypass valve (104) is designed as an overflow valve. [6] System (120) according to one of claims 1 to 4, wherein the bypass valve (104) is designed as a solenoid valve. [7] Method for the thermal disinfection of a reverse osmosis system (100), wherein water is conveyed from the reverse osmosis system (100) through a feed line (101) into a hot cleaning system (103) and heated there, and wherein the heated water is conveyed from the hot cleaning system (103) through a return line (106) into the reverse osmosis system (100), characterized by the steps • Specifying a disinfection target for the reverse osmosis system (100); • Check the disinfection status of the reverse osmosis system (100); • when the specified disinfection target of the reverse osmosis system (100) is reached, the pumping of heated water through the return line (106) is stopped and the heated water is pumped from the supply line (106) via a bypass line (102) into the return line (101). [8] Method according to claim 7, wherein during the conveyance of heated water through the return line (106) through the bypass line (102) only a volume flow of heated water is conveyed which is less than or equal to a predetermined volume flow threshold value. [9] Method according to claim 8, wherein heated water is conveyed through a ring line (108) connected to the hot cleaning system (103). [10] Method according to claim 9, wherein heated water is provided to at least one consumer (109) connected to the ring line (108), and wherein the provided flow rate is fed in by a booster pump of the reverse osmosis system (100).

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