Device and method for producing pure water with high quality requirements, such as pure water for pharmaceutical applications

Abstract

The present invention relates to a line system (100) which can be operated in a normal mode and in a cleaning mode, comprising: an annular pipeline (3) having a main pipeline (10), an annular pipeline feed (70) and an annular pipeline return (80), and preferably at least one secondary pipeline (20); a flow-reducing element; at least one pressure compensation container (60) and / or at least one pump (62), wherein the annular pipeline feed (70) can be connected to an outlet (91) of a water treatment system (90), and the annular pipeline return (80) can be connected to an inlet (41) of a storage tank (40), wherein the storage tank (40) is located at the inlet (92) of the water treatment system and wherein the line system (100) comprises a bypass pipeline (50) in order to enable the annular pipeline feed (70) to be connected to the storage tank (40); and the pressure compensation container (60) is arranged in the annular pipeline return (80).

Description

[0001] Device and method for producing pure water with high quality requirements, such as pure water for pharmaceutical applications.

[0002] Technical field of the invention

[0003] The present invention relates to a piping system through which pure water is supplied, in particular for pharmaceutical applications, e.g., for dialysis. However, the invention also relates to other applications where high demands are placed on the quality of the pure water, such as drinking water, water in chip manufacturing, etc. Therefore, the piping system must be cleaned regularly. The piping system according to the invention is characterized in that, during normal operation, the water flows through the piping system in a main flow direction, and during cleaning operation, it flows in a counter-flow direction. Since the counter-flow of the water can be pulsed, the cleaning of the piping system is particularly effective. The method for cleaning the piping system is therefore also part of the present invention.

[0004] The piping system according to the invention comprises a ring pipeline with a ring pipeline supply, a ring pipeline return, a main pipeline, and a withdrawal point for purified water, particularly for pharmaceutical applications, as well as preferably with at least one secondary pipeline, a flow-reducing element, at least one pressure equalization tank, and / or at least one pump; wherein the ring pipeline supply is connectable to an outlet of a water treatment plant and the ring pipeline return is connectable to an inlet of a storage tank; wherein the storage tank is located at the inlet of the water treatment plant. The piping system according to the invention is characterized in that it comprises a bypass pipeline to enable the connection of the ring pipeline supply to the storage tank; and the at least one pressure equalization tank and / or the at least one pump is / are arranged in the ring pipeline return.The respective connections can be shut off using appropriate valves.

[0005] The bypass pipeline, which is used in the cleaning operation of the pipeline system, allows the flow through the pipeline system for cleaning.

[0006] Furthermore, another object of the invention is a device for the production of pure water, in particular for pharmaceutical applications, which includes the piping system according to the invention.

[0007] State of the art

[0008] A known system, as shown in Fig. 1, involves connecting a ring main to a water treatment plant such that the ring main's supply line is connected to the outlet of the water treatment plant and the ring main's return line is connected to the inlet of a storage tank at the water treatment plant's inlet via two lines. One line in the ring main's return line is lockable.

[0009] During cleaning of the ring main, the valve at the inlet of the buffer tank is briefly opened and closed. This causes the water contained in at least one pressure equalization tank located in the ring main's supply line to be fed through the ring main in pulses, thus cleaning it. It has been shown that this type of cleaning is insufficient. The available differential pressure is also lower, since the ring main's return line already operates at a lower pressure, and the differential pressure is further reduced (e.g., from 4 bar to 0 bar) by the open pressure-maintaining valve (V2) and the opening of VI. (See Figs. 8a and 8b) Furthermore, there is a risk that the pressure equalization tank may be damaged, and contaminated water, instead of clean water, could then be unknowingly fed into the pharmaceutical piping system for an extended period of time through the pressure equalization tank located in the supply line.

[0010] The object of the present invention is therefore to provide a piping system that can be cleaned more efficiently and offers maximum safety in normal operation.

[0011] Summary of the invention

[0012] This problem is solved by a piping system that can be operated in normal operation and in cleaning operation, and a) a ring pipeline through which water can flow in a main flow direction in normal operation and in a counter-flow direction in cleaning operation, wherein the ring pipeline (3) comprises a main pipeline and at least one outlet for purified water, in particular for pharmaceutical applications, wherein the ring pipeline comprises a ring pipeline supply and a ring pipeline return; and b) a flow-reducing element; and c) at least one pressure equalization tank and / or at least one pump; wherein the ring pipeline supply of the ring pipeline can be connected to an outlet of a water treatment plant and shut off by a first valve;wherein the return line of the ring pipeline can be connected to an inlet of a storage tank, and wherein the storage tank is located at the inlet of the water treatment plant.

[0013] The inventive piping system is characterized by the fact that

[0014] - the piping system includes a bypass pipeline with a second lockable valve, through which the annular pipeline supply line of the annular pipeline can be connected to the storage tank;

[0015] - which includes at least one pressure equalization tank and / or at least one pump in the return loop of the ring pipeline;

[0016] - the flow reducing element is arranged in the return loop of the ring pipeline and in the main flow direction after the pressure equalization tank or the pump, wherein in normal operation the first valve is open towards the outlet of the water treatment plant and the second valve of the bypass pipeline is closed; while in cleaning operation the first valve is closed towards the outlet of the water treatment plant and the third valve is open.

[0017] The extraction point for the purified water, particularly for pharmaceutical applications, can be located at any point along the ring main. It can also be located, for example, on a preferably existing lateral pipe. Multiple extraction points are also possible. In one embodiment of the piping system according to the invention, several lateral pipes are present, with an extraction point located on each lateral pipe.

[0018] In an alternative embodiment of the piping system according to the invention, the first and second valves are replaced by a corresponding three-way valve.

[0019] In an alternative embodiment of the piping system according to the invention, the first valve is designed as a check valve and then automatically shuts off the ring pipe supply line.

[0020] The flow-reducing element can be formed by a constriction, a throttle, an orifice, a third valve, or a pressure-reducing valve. The third valve can be lockable or non-lockable. The third valve can also be a pressure-reducing valve, which can be lockable or non-lockable. In a preferred embodiment of the piping system according to the invention, the flow-reducing element is formed by a combination of a lockable third valve and a pressure-reducing valve.

[0021] Under normal operating conditions, the water fed into the storage tank at the inlet of the water treatment plant flows through the water treatment plant, where it is purified. From the outlet of the water treatment plant, the purified water then flows into the annular supply line of the ring main and can then be distributed via the main line to the preferably present at least one branch line, from where it can be drawn off, for example, at its point of use for pharmaceutical purposes, such as for a dialysis machine. Any water not drawn off flows from there into the annular return line and from there back into the storage tank. To compensate for pressure fluctuations in the pipelines, at least one pressure equalization tank is located in the annular return line.Instead of or in addition to at least one pressure equalization tank, the ring pipe return line can also include at least one pump. The size of the at least one pressure equalization tank is specifically adapted to the ring pipe size. In a preferred embodiment, the at least one pressure equalization tank has a capacity of at least 0.01 liters, preferably from 0.01 to 100 liters. Instead of or in addition to a pump, the ring pipe return line can also include a pressure relief valve.

[0022] The present invention also includes an embodiment in which there is no pressure equalization tank in the annular pipe return line, but instead a pump. Preferably, this embodiment has an additional fourth valve that opens and closes while the pump is running. In an alternative embodiment, a pressure equalization tank is also provided, which can also be located at a different location than in the annular pipe return line. In this case, however, it must be ensured that the "cleaning water" is not stagnant or of lower quality.

[0023] Under normal operating conditions, the second valve of the bypass pipeline is closed and the first valve at the outlet of the water treatment plant is open, meaning that the connection to the outlet of the water treatment plant is open and the connection to the bypass pipeline is closed. If present, the third lockable valve for the storage tank is also open.

[0024] During cleaning operation, the second valve opens, thus opening the connection to the bypass pipeline, and closes the connection to the outlet of the water treatment plant. If the first valve is designed as a check valve, the ring main supply line is automatically shut off. If present, the third lockable valve for the storage tank is also closed.

[0025] The second valve can be located at the ring main supply side of the bypass pipeline, at the storage tank side of the bypass pipeline, or at any point along the bypass pipeline.

[0026] If, during cleaning operations, the second valve of the bypass pipeline is briefly opened at regular intervals, this leads to a pressure drop in the ring main supply line and thus to at least partial emptying of the at least one expansion tank, as long as the expansion tank is not empty. To prevent the expansion tank from emptying completely, the second valve is preferably closed by a pressure monitoring system as soon as a certain amount of water in the expansion tank falls below a certain threshold. Closing the second valve of the bypass pipeline causes pressure to build up again in the ring main return line, which then drops when the valve opens. The cleaning intervals are usually determined by the operator of the pipeline system and / or by the company that receives the treated water.Since at least one pressure equalization tank is located on the return line of the ring main, the water flows through the ring main in the opposite direction of flow. This makes the removal of any deposits present in the main flow direction, and thus the cleaning of the ring main, particularly efficient. This process cleans not only the main line and the supply and return lines of the ring main, but also any existing branch line.

[0027] If the first and second valves are replaced by a corresponding three-way valve, it is normally set so that the connection to the outlet of the water treatment plant is open and the connection to the bypass pipeline is closed. Additionally, if present, the third lockable valve for the storage tank is open during normal operation.

[0028] During cleaning operation, the three-way valve is set so that the connection to the outlet of the water treatment plant is closed and the connection to the bypass pipeline is open. Additionally, if present, the third lockable valve for the storage tank is closed.

[0029] If, during cleaning operation, the three-way valve to the bypass pipeline is briefly opened at regular intervals, this causes a pressure drop in the line and thus at least a partial emptying of the at least one expansion tank. Since the at least one expansion tank is located on the return line of the ring main, the water flows in the opposite direction through the ring main. This makes the removal of any deposits present in the main flow direction and thus the cleaning of the ring main particularly efficient. This process cleans not only the main line and the supply and return lines of the ring main, but also the at least one bypass line.

[0030] Therefore, a further object of the invention is a method for cleaning the piping system according to the invention, wherein the method comprises the following steps: i) closing the connection between the outlet of the water treatment plant and the annular supply line of the annular pipeline and opening the bypass pipeline by appropriately positioning the first and second valves or the three-way valve; ii) flushing the annular pipeline and the bypass pipeline in the counterflow direction with at least a part of the water located in a pressure equalization tank by opening the second lockable valve of the bypass pipeline towards the storage tank of the water treatment plant.

[0031] If a third lockable valve is present leading to the storage tank of the water treatment plant, this is also closed in step i).

[0032] In this process, the ring main and the bypass main are automatically flushed in the opposite direction by a portion of the water contained in at least one pressure equalization tank when the second lockable valve of the bypass main to the water treatment plant's storage tank is opened. This process can be repeated as often as necessary (until the pressure equalization tank is empty) and is preferably carried out after supply operation and / or before the next supply operation or a renewed short-term pressure build-up. The frequency depends on the operator's individual requirements. In a preferred embodiment, the closing and reopening of the second valve of the bypass main to the water treatment plant's storage tank occurs briefly and thus in a pulsed manner. This type of flushing of the piping system is also referred to as pulse flushing.The inventive piping system can therefore be operated in a pulsed counterflow mode. The normal and / or cleaning and / or pulsed counterflow modes of the inventive piping system can be automated and thus performed automatically.

[0033] After cleaning the pipe system, it is advantageous to flush the main pipeline and, if present, at least one secondary pipeline with fresh, clean water within a few minutes, restoring the normal flow direction. This technique achieves improved clean water quality (reduced germ and endotoxin levels) and thus better patient health. Furthermore, this technique eliminates the need for costly and energy-intensive hot water disinfection, or at least reduces its duration and frequency.

[0034] Therefore, in a further preferred embodiment, the method includes the additional step iii): iii) Flushing the ring pipeline and the bypass pipeline in the main flow direction with pure water for pharmaceutical applications.

[0035] Further preferred embodiments of the piping system according to the invention are described below. In one embodiment of the piping system according to the invention, the ring main contains at least one branched lateral pipe forming a bypass. Preferably, the at least one outlet for purified water, particularly for pharmaceutical applications, is connected to the lateral pipe.

[0036] In a further preferred embodiment, the piping system according to the invention comprises a sensor with which the pressure difference or flow velocity of the water in the piping system can be measured and / or controlled. Preferably, the sensor is designed as a pressure sensor.

[0037] In a further embodiment, the piping system according to the invention comprises at least one pump, which is arranged in the main flow direction upstream or downstream of the at least one pressure equalization tank. The pump can not only be additionally present, but can also replace the at least one pressure equalization tank.

[0038] A further object of the invention is a device for producing pure water for pharmaceutical applications, which comprises the piping system according to the invention, as well as a storage tank and a water treatment plant with an outlet to the piping system according to the invention, wherein the storage tank is located at the inlet of the water treatment plant.

[0039] Such water treatment plants are already known from the prior art, for example from EP 3 372 302 or EP 2 723 693. In a preferred embodiment of the device according to the invention, the water treatment plant comprises at least one, advantageously two, preferably three reverse osmosis systems.

[0040] Brief description of the drawings

[0041] Fig. 1 shows a device for the production of pure water for pharmaceutical applications according to the prior art.

[0042] Figs. 2-8 show devices according to the invention for the production of pure water for pharmaceutical applications.

[0043] Description of a device according to the state of the art

[0044] In the prior art device 2000 shown in Figure 1, the piping system 100 is connected to the outlet 91 of the water treatment plant and to the inlet of the storage tank 40 at two points. The piping system 100 comprises a ring main 3 with a main pipe 10 and two branch pipes 20, 20', each with a draw-off point 30, 30'. Here, the draw-off points 30, 30' are for the purified water produced in the device 2000, for example, dialysis machines D, D'. The ring main supply 70, which includes a pressure equalization tank 60, is connected to the outlet 91 of the water treatment plant and can be shut off via a valve VI. The ring main return 80 is connected to the inlet 41 of the storage tank via both the valve VI and the pressure-maintaining valve V2. The water treatment plant 90 has two reverse osmosis systems 4 and 5 and is connected back to the storage tank 40.In normal operation, valve V2 is open and the purified water produced in the water treatment plant 90 flows via its outlet 91 and the pressure equalization tank 60 into the main pipeline 10 and the secondary lines 20 and 20' and then back into the storage tank via the ring pipeline return 80.

[0045] During cleaning, valve V2 remains open and valve VI is opened. Briefly opening and closing valve VI causes the water in the pressure equalization tank 60 to perform a pulse flush of the piping system 100 in the main flow direction 1. The piping system 100 cannot be flushed in the opposite direction. Since the pressure at the return line of the ring main is lower due to the open valve V2 than in the supply line of the ring main, only a small differential pressure and thus a weak pulse flush can occur.

[0046] Preferred embodiments of the invention

[0047] In the device 1000 according to the invention shown in Figure 2, the piping system 100, which can be operated in normal operation and in cleaning operation, is connected to a storage tank 40 and a water treatment plant 90 such that the annular pipe supply line 70 of its annular pipe is connected to an outlet 91 of the water treatment plant and can be shut off by a first valve 52-1, and that the annular pipe return line 80 of its annular pipe is connected to a first inlet 41 of the storage tank and can be shut off by a third valve 48, and also includes a pressure-maintaining valve 61. The first valve 52-1 can also be designed as a check valve and then automatically shuts off the annular pipe supply line 70.In addition to the ring main supply line 70 and the ring main return line 80, the ring main 3 comprises a main line 10 and at least one, here two, branched-off secondary line(s) 20, 20' forming a bypass, to which at least one outlet 30, 30' for purified water, particularly for pharmaceutical applications, can be connected. The ring main 3 is designed to carry water in a main flow direction 1 during normal operation and in a counter-flow direction 2 during cleaning operation. The piping system 100 also includes a pressure equalization tank 60, which is located in the ring main return line 80 of the ring main. The storage tank 40 is located at the inlet 92 of the water treatment plant. The inventive piping system 100 is characterized by the fact that it comprises a bypass pipeline 50 through which the annular pipeline supply line 70 of the annular pipeline is connected to the storage tank 40.The bypass pipeline 50 includes a second valve 52-2, which enables the opening and closing of the connection between bypass pipeline 50 and the ring pipeline supply line 70 of the ring pipeline.

[0048] In normal operation, the second valve 52-2 is closed, while valves 48 and 52-1 are open. During cleaning, the situation is reversed: valves 48 and 52-1 are closed, and the second valve 52-2 is opened. If, during cleaning, the second valve 52-2 of the bypass pipeline to the storage tank 40 is briefly opened, this causes a pressure drop in the annular supply line 70 and thus at least partial emptying of the pressure equalization tank 60 with a nearly constant pressure differential, as long as the pressure equalization tank 60 is not completely empty. To prevent this, the valve 52-2 is preferably closed by a pressure monitoring system before the pressure equalization tank is completely empty. Closing the second valve 52-2 restores pressure in the annular supply line 70.Opening the second valve 52-2 then leads to a pressure drop and a counterflow of water. Preferably, the valve 52-2 is opened and closed multiple times during cleaning to generate multiple counterflow pulses. Since the pressure equalization tank 60 is located on the return line 80 of the ring main, the water flows counterflow 2 through the ring main 3. This makes the removal of any deposits present in the main flow direction 1, and thus the cleaning of the ring main 3, particularly efficient. This process cleans not only the main line 10 and the supply and return lines 70 and 80 of the ring main, but also the two secondary lines 20 and 20'.

[0049] Fig. 3 shows an alternative embodiment of the device 1000 according to the invention, in which the first valve 52-1 and the second valve 52-2 are replaced by a corresponding three-way valve 52.

[0050] Fig. 4 shows an alternative embodiment of the device 1000 according to the invention, in which an additional pump 62 is used to increase the pressure differential. The pump 62 can be used in addition to or instead of the pressure equalization tank for flushing the lines.

[0051] In normal operation, the second valve 52-2 is closed, while the two valves 48 and 52-1 are open. In cleaning mode, it is exactly the opposite: Valves 48 and 52-1 are closed and the second valve 52-2 is open.

[0052] If, during cleaning operation, the second valve 52-2 of the bypass pipeline to the storage tank 40 is briefly opened, this causes a pressure drop in the line and thus a partial emptying of the pressure equalization tank 60. Since the pressure equalization tank 60 is located on the return line 80 of the ring pipeline, the water flows in the opposite direction 2 through the ring pipeline 3. This makes the removal of any deposits present in the main flow direction 1 and thus the cleaning of the ring pipeline 3 particularly efficient. This process cleans not only the main line 10 and the supply and return lines 70 and 80 of the ring pipeline, but also the two secondary lines 20 and 20'. The pump 62 serves as an additional boost for the pressure equalization tank.

[0053] The alternative embodiment of the device according to the invention shown in Fig. 5 has a further line 53 with a fourth valve 58, which opens and closes as soon as the pump is running. This enables counter-circulation by the pump. During cleaning operation, both line 53 and the bypass pipe 50 are subjected to flow in the opposite direction (2-2 and 2-1, respectively).

[0054] The alternative embodiment of the device 1000 according to the invention shown in Fig. 6 differs from the embodiment of the device 1000 according to the invention shown in Fig. 5 in that it does not have a pressure equalization tank 60 in the ring pipe return 80.

[0055] The alternative embodiment of the device 1000 shown in Fig. 7 differs from the embodiment of the device 1000 shown in Fig. 2 in that it does not have any secondary pipes 20, 20' in the ring pipe 3, and the at least one extraction point 30 for pure water for pharmaceutical applications is connected to the main pipe 10.

[0056] Fig. 8a shows a piping system 100 of the device 1000 according to the invention in normal operation, with the ring pipe 3 being flowed through in the main flow direction 1. Fig. 8b shows the same piping system 100 in cleaning operation. By first building up pressure through the pressure equalization tank and closing the valves 48, 52-1 and 52-2, a high uniform pressure is achieved in the entire piping system 100. By subsequently opening the valve 52-2, the pressure is then released in the opposite flow direction 2 in the pipe supply line 70.

[0057] Reference symbol list

[0058] 1000 Device according to the invention

[0059] 2000 device according to the state of the art

[0060] 100 pipeline system

[0061] 1 Main flow direction of the ring pipeline 3

[0062] 2 Counterflow direction of the ring pipeline 3

[0063] 3 Ring pipeline

[0064] 4, 5 Reverse osmosis system

[0065] 10 Main pipeline

[0066] 20, 20' secondary pipeline

[0067] 30, 30' sampling point

[0068] 40 feed tank

[0069] 41 First inlet of the feed tank 40

[0070] 42 second inlet of the feed tank 40

[0071] 48 third valve for the first inlet 41 of the feed tank 40

[0072] 50 Bypass pipeline 51 Ring pipeline supply side end of the bypass pipeline

[0073] 50

[0074] 52 Three-way valve of the bypass pipeline 50

[0075] 52-1 first valve at the outlet of the water treatment plant 90 52-2 second valve of the bypass pipeline

[0076] 53 Management

[0077] 54 End of bypass pipeline on the feed tank side 50

[0078] 58 fourth valve

[0079] 60 Pressure equalization tank 61 Pressure holding valve

[0080] 62 Pump

[0081] 70 Ring pipe supply

[0082] 80 Ring pipe return

[0083] 90 Water treatment plant 91 Outlet of the water treatment plant

[0084] 92 Inlet of the water treatment plant

[0085] VI, V2 valves

[0086] D, D' Dialysis machine

Claims

Patent claims 1. A piping system (100) that can be operated in normal operation and in cleaning operation, comprising: a) a ring pipeline (3) through which water can flow in a main flow direction (1) in normal operation and in a counter-flow direction (2) in cleaning operation, wherein the ring pipeline (3) comprises a main pipeline (10) and at least one outlet (30) for purified water, in particular for pharmaceutical applications, wherein the ring pipeline (3) comprises a ring pipeline supply (70) and a ring pipeline return (80); and b) a flow reducing element; and c) at least one pressure equalization tank (60) and / or at least one pump (62);wherein the annular pipeline supply (70) of the annular pipeline is connectable to an outlet (91) of a water treatment plant (90) and can be shut off by a first valve (52-1), wherein the annular pipeline return (80) of the annular pipeline is connectable to a first inlet (41) of a storage tank (40), and wherein the storage tank (40) is located at the inlet (92) of the water treatment plant, characterized in that the pipeline system (100) comprises a bypass pipeline (50) with a second shut-off valve (52-2) through which the annular pipeline supply (70) of the annular pipeline can be connected to the storage tank (40), and that the at least one pressure equalization vessel (60) and / or the at least one pump is arranged in the annular pipeline return (80) of the annular pipeline; that the flow reducing element is arranged in the ring pipe return (80) of the ring pipe and in the main flow direction after the pressure equalization tank or the pump, wherein in normal operation the first valve (52-1 ) is open towards the outlet (91 ) of the water treatment plant and the second valve (52-2) of the bypass pipe is closed, while in cleaning operation the first valve (52-1 ) towards the outlet (91 ) of the water treatment plant is closed and the second valve (52-2) is open.

2. Conduit system (100) according to claim 1 , characterized in that the ring pipeline (3) contains at least one branched secondary pipeline (20) forming a bypass, to which the at least one withdrawal point (30) for purified water for pharmaceutical applications is connected.

3. Conduit system (100) according to claim 1 or claim 2, characterized in that the flow-reducing element (81 ) is formed by a constriction, a throttle, an orifice, a third valve (48) or a pressure-holding valve (61 ).

4. Piping system (100) according to claim 3, characterized in that the third valve (48) is lockable.

5. Piping system according to claim 3, wherein the third valve (48) is not lockable.

6. Piping system (100) according to one of claims 3 to 5, wherein the third valve (48) and the pressure holding valve (61) form a combined valve.

7. Piping system (100) according to one of claims 1 to 6, characterized in that the first valve (52-1 ) and the second valve (52-2) are replaced by a corresponding three-way valve (52).

8. Piping system (100) according to one of claims 1 to 8, characterized in that the first valve (52-1 ) is designed as a check valve and automatically shuts off the annular pipe supply (70).

9. Piping system (100) according to one of claims 1 to 8, characterized in that the piping system (100) comprises at least one sensor, preferably at least one pressure sensor, with which the pressure difference or flow velocity of the water in the piping system (100) can be measured and / or controlled.

10. Piping system (100) according to one of claims 1 to 9, characterized in that the second valve (52-2) of the bypass pipeline or the three-way valve (52) can be momentarily opened and closed, so that the piping system (100) can be operated in pulse mode.

12. Conduit system (100) according to one of claims 1 to 1 1 , characterized in that the conduit system (100) can be operated in an automatic normal and / or cleaning and / or pulse operation.

13. Piping system (100) according to one of claims 1 to 12, characterized in that the capacity of the at least one pressure equalization vessel (60) is at least 0.01 liters, preferably 0.01 to 100 liters.

14. Device (1000) for producing pure water for pharmaceutical applications, comprising the piping system (100) according to one of claims 1 to 13, as well as a storage tank (40) and a water treatment plant (90) with an outlet (91) to the piping system (100), wherein the storage tank (40) is located at the inlet (92) of the water treatment plant.

15. Device according to claim 14, characterized in that the water treatment plant (90) comprises at least one, advantageously two, preferably three reverse osmosis systems.

16. Method for cleaning the piping system (100) according to any one of claims 1 to 13, the method comprising the following steps: i) closing the connection between the outlet (91) of the water treatment plant and the annular supply line (70) of the annular pipeline and opening the bypass pipeline (50) by appropriately positioning the first valve (52-1) and the second valve (52-2) or the three-way valve (52); ii) flushing the annular pipeline (3) in the counterflow direction (2) with a portion of the water located in the at least one pressure equalization tank (60) by opening the second lockable valve (52-2) or the three-way valve (52) towards the storage tank of the water treatment plant.

17. Method according to claim 16, characterized in that the flushing is carried out in pulses by briefly closing and reopening the second lockable valve (52-2) or the three-way valve. Valve (52) to the storage tank (40) of the water treatment plant.

18. Method according to one of claims 16 or 17, wherein the piping system (100) comprises a water treatment plant and wherein the water treatment plant remains in operation or is restarted for re-pressure build-up.

19. Method according to one of claims 16 to 18, characterized in that the method comprises the additional step iii): iii) Flushing the ring pipeline (3) in the main flow direction (1 ) with pure water for pharmaceutical applications.

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