CN215365178U

CN215365178U - Water purifier for preventing pure water TDS from rising

Info

Publication number: CN215365178U
Application number: CN202121741062.XU
Authority: CN
Inventors: 汝彬; 韩荣耀
Original assignee: Suzhou Pentair Water Treatment Co ltd
Current assignee: Suzhou Pentair Water Treatment Co ltd
Priority date: 2021-07-29
Filing date: 2021-07-29
Publication date: 2021-12-31
Anticipated expiration: 2031-07-29

Abstract

The utility model relates to a water purifier for preventing pure water TDS from rising, which comprises an RO filter element, a water inlet pipeline, a waste water pipeline, a pure water pipeline and a control valve component, wherein the control valve component comprises a first control valve arranged on the water inlet pipeline and a second control valve arranged on the pure water pipeline; the membrane of the water purifier is washed by the concentrated water in the internal circulation process, so that the membrane load is reduced, and the service life of the membrane is prolonged; the water purifier utilizes the water tank to replace the concentrated water on the concentrated water side, does not increase the consumption of water, avoids the waste of water resources, and is economic and environment-friendly.

Description

Water purifier for preventing pure water TDS from rising

Technical Field

The utility model relates to the field of water purification equipment, in particular to a water purifier for preventing TDS (total dissolved solids) of pure water from rising.

Background

Effluent TDS is the main index of weighing RO purifier filter effect, and the removal rate of RO machine TDS when normal continuous operation can reach more than 90%, and it carries out reverse osmosis phenomenon at normal during operation, and reverse osmosis refers to under certain pressure, and the solvent in the high concentration solution passes through the pellicle, to the phenomenon that low concentration solution shifted, and its realization needs overcome osmotic pressure. However, when the RO machine stops working, TDS in raw water penetrates the RO membrane by forward osmosis, and the concentrated water on the concentrated water side of the RO filter element, which contains TDS (ions and organic matter with high concentration), can slowly diffuse to the pure water side, and the diffusion time starts to appear in more than 5 minutes, and if the diffusion time is long enough, the concentrations on both sides can reach equilibrium. Therefore, through overnight diffusion, the TDS value of the pure water in the pure water side is obviously increased, if more heavy metal ions are contained in the raw water, the heavy metals in the pure water also exceed the standard, and the water quality and the taste are greatly influenced. When the RO machine is changed from the shutdown state to the water production state, the produced pure water is mixed with the transmitted TDS and comes out together. The pure water side water is generally determined by the size of the membrane shell, which causes the TDS value of the first cup of water after the water purifier starts to work again to be higher.

Have among the prior art to add a pure water jar (also called pressure tank) behind the RO membrane, can dilute the TDS that permeates like this, traditional pure water jar is mostly the pressure tank and is implemented through pressure, wherein has accessories such as gasbag, inside breeds bacterial microorganism etc. easily. Some traditional overhead tanks supply first cup of water through storing RO water in the jar, influence the taste, and the bacterium breeds easily for a long time of stewing. Is unsanitary; some traditional pressure tanks are also ejecting the waste water of the RO membrane through the RO water stored in the tank, so that the TDS of the outlet water is low, but the volume of the tank is larger than 1L, the tank occupies space, and then the waste of water resources is caused by direct drainage. In the prior art, some devices only dilute concentrated water in a pure water backflow mode, and adjust the flow rate according to a TDS value after shutdown to adjust the proportion of raw water and pure water entering an RO filter element, so that water is wasted; some equipment regularly washes with the pure water, forces the TDS value of former water end, waste water end the same with the TDS value of pure water end, does so and can lead to more water waste to can lead to the life-span reduction of RO membrane. Therefore, the solutions in the prior art are not economical and environment-friendly.

Disclosure of Invention

An object of the present invention is to provide a water purifier which prevents the TDS of pure water from rising.

In order to achieve the purpose, the utility model adopts the technical scheme that:

a water purifier for preventing pure water TDS from rising comprises an RO filter element, a water inlet pipeline, a waste water pipeline, a pure water pipeline and a control valve component, wherein the water inlet pipeline and the waste water pipeline are communicated with the concentrated water side of an RO membrane in the RO filter element, the pure water pipeline is communicated with the pure water side of the RO membrane in the RO filter element, the control valve component comprises a first control valve arranged on the water inlet pipeline and a second control valve arranged on the pure water pipeline,

the water purifier also comprises a water storage pipeline, a replacement pipeline and a first TDS detection component, wherein the water storage pipeline comprises a water storage water inlet pipe, a water storage water outlet pipe and a replacement water storage component connected between the water storage water inlet pipe and the water storage water outlet pipe, and the water storage water inlet pipe and the water storage water outlet pipe are respectively communicated with the pure water pipeline; one end of the replacement pipeline is communicated with the pure water pipeline at the upstream of the second control valve, the other end of the replacement pipeline is communicated with the water inlet pipeline at the downstream of the first control valve, the first TDS detection component is arranged on the pure water pipeline at the downstream of the communication position of the water storage water outlet pipe and the pure water pipeline,

the control valve assembly further comprises at least one of a third control valve and a fourth control valve and a fifth control valve, the third control valve is arranged on one of the water storage water inlet pipe and the water storage water outlet pipe, the fourth control valve is arranged on the pure water pipeline and a pipe section between the water storage water inlet pipe and the water storage water outlet pipe, and the fifth control valve is arranged on the replacement loop.

Preferably, the third control valve and the fourth control valve are arranged at the same time.

More preferably, the water purifier has a water production state and a replacement state, and in the water production state: the first control valve is opened, the second control valve is opened, one of the third control valve and the fourth control valve is opened, and the fifth control valve is closed; in the replacement state: the first control valve is closed, the second control valve is closed, the third control valve is opened, the fourth control valve is closed, and the fifth control valve is opened.

More preferably, the water production state comprises a first water production state and a second water production state,

when the detection value of the first TDS detection component is smaller than the set value, the water purifier is in a first water production state: the first control valve is opened, the second control valve is opened, the third control valve is opened, the fourth control valve is closed, and the fifth control valve is closed;

when the detection value of the first TDS detection component is larger than or equal to the set value, the water purifier is in a second water production state: the first control valve is opened, the second control valve is opened, the third control valve is closed, the fourth control valve is opened, and the fifth control valve is closed.

Preferably, the water purifier further comprises a control component, and the control component is connected with the first TDS detection component and the control valve component.

Preferably, the third control valve is arranged on the water storage and outlet pipe.

Preferably, the water purifier further comprises a pump body and a pressure protection pipeline, the pump body is arranged on a water inlet pipeline at the downstream of the communication position of the water inlet pipeline and the displacement pipeline, one end of the pressure protection pipeline is communicated with the wastewater pipeline, the other end of the pressure protection pipeline is communicated with the water inlet pipeline, the control valve assembly further comprises a sixth control valve, and the sixth control valve is arranged on the pressure protection pipeline.

Preferably, the water purifier further comprises a front filter element and/or a rear filter element, the front filter element is arranged on the water inlet pipeline at the upstream of the communication position of the water inlet pipeline and the replacement pipeline, and the rear filter element is arranged on the pure water pipeline at the upstream of the communication position of the pure water pipeline and the replacement pipeline.

Preferably, the water purifier further comprises a second TDS detection component, wherein the second TDS detection component is arranged on the water inlet pipeline at the upstream of the communication position of the water inlet pipeline and the replacement pipeline.

Preferably, the control valve assembly further includes at least one of a first check valve, a second check valve and a third check valve, the first check valve is disposed on the pure water pipeline upstream of the communication between the pure water pipeline and the replacement pipeline, the second check valve is disposed on the pure water pipeline downstream of the communication between the pure water pipeline and the replacement pipeline, and the third check valve is disposed on the replacement pipeline.

Preferably, the water purifier further comprises a switch, the switch is arranged on the pure water pipeline downstream of the second control valve, the control valve assembly further comprises a waste water valve, and the waste water valve is arranged on the waste water pipeline.

Due to the application of the technical scheme, compared with the prior art, the utility model has the following advantages:

the utility model solves the problem of high TDS in a period of time after the RO machine is shut down through pure water circulation and replacement, so that the water drunk by a user has no old water; the membrane of the water purifier is washed by the concentrated water in the internal circulation process, so that the membrane load is reduced, and the service life of the membrane is prolonged; the water purifier utilizes the water tank to replace the concentrated water on the concentrated water side, does not increase the consumption of water, avoids the waste of water resources, and is economic and environment-friendly.

Drawings

Fig. 1 is a schematic view of the waterway structure of this embodiment.

In the above drawings: 1. a water inlet pipeline; 2. a pure water line; 3. a waste water line; 41. a water storage and inlet pipe; 42. a water storage and outlet pipe; 43. a replacement water storage member; 5. replacing the pipeline; 6. a pressure protection line; 70. a first control valve; 71. a second control valve; 72. a third control valve; 73. a fourth control valve; 74. a fifth control valve; 75. a sixth control valve; 76. a waste water valve; 77. a first check valve; 78. a second check valve; 79. a third check valve; 81. an RO filter element; 82. a first TDS detection component; 83. a second TDS detection section; 84. a pump body; 85. a front filter element; 86. a post-filter element, 87 and a switch.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in FIG. 1, a water purifier for preventing pure water TDS from rising comprises an RO filter element 81, a water inlet pipeline 1, a waste water pipeline 3, a pure water pipeline 2, a water storage pipeline, a replacement pipeline 5 and a control valve component, wherein the water inlet pipeline 1 is used for connecting a raw water source, the water inlet pipeline 1 and the waste water pipeline 3 are communicated with the concentrated water side of an RO membrane in the RO filter element 81, the pure water pipeline 2 is communicated with the pure water side of the RO membrane in the RO filter element 81, the pure water pipeline 2 is used for providing purified water for a user, two ends of the water storage pipeline are communicated on the pure water pipeline 2, one end of the replacement pipeline 5 is communicated on the pure water pipeline 2 and is positioned at the downstream of the water storage pipeline, and the other end is communicated on the water inlet pipeline 1.

The pure water pipeline 2 is provided with a switch 87, and a user can directly receive healthy water meeting the TDS set value requirement by opening the switch 87. The water storage pipeline comprises a water storage water inlet pipe 41, a water storage water outlet pipe 42 and a replacement water storage part 43 connected between the water storage water inlet pipe 41 and the water storage water outlet pipe 42, and the water storage water inlet pipe 41 and the water storage water outlet pipe 42 are respectively communicated with the pure water pipeline 2. One end of the substitution line 5 communicates with the pure water line 2 upstream of the switch 87, and the other end of the substitution line 5 communicates with the water inlet line 1. The water purifier can select to pass through or directly pass through from the holding pipeline according to the TDS value when making water from pure water pipeline 2, can let the user directly drink the water that satisfies the TDS setting value requirement, water and RO filter core 81 in the water in the holding pipeline through replacement pipeline 5 after system water finishes the dense water side of RO membrane water filtration replacement, reduce dense water side TDS value, avoid shutting down to take place just permeating for a long time and lead to the TDS value of pure water side to rise.

The water purifier further includes a first TDS detecting part 82, a second TDS detecting part 83, and a control part connected to the first TDS detecting part 82, the second TDS detecting part 83, the control valve assembly, and the switch 87. First TDS detects component 82 sets up on the pure water pipeline 2 of retaining outlet pipe 42 and pure water pipeline 2 intercommunication department low reaches, second TDS detects component 83 sets up on the inlet water pipeline 1 of inlet water pipeline 1 and replacement pipeline 5 intercommunication department upper reaches, first TDS detects component 82, the TDS data that second TDS detects component 83 to the control unit feedback detected, the TDS data that the control unit judgement analysis detected, and the switching of each valve is in order to realize the circulation in different waterways in the control valve subassembly. When the user opens or closes the switch 87, the switch 87 sends a command to the control unit to instruct the water purifier to supply water to the outside. The first TDS detecting part 82 is further provided with an NTC element for protecting the circuit.

The control valve assembly includes a first control valve 70, a second control valve 71, a third control valve 72, a fourth control valve 73, a fifth control valve 74 and a waste valve 76. The first control valve 70 is provided on the water inlet line 1 upstream of the second TDS detecting part 83 to control whether or not raw water flows into the RO filter cartridge 81. The second control valve 71 is provided on the plain water line 2 upstream of the switch 87 and downstream of the connection of the plain water line 2 to the substitution line 5, and prevents the flow of water to the switch 87 and to the substitution line 5 when the flow of water to the substitution line 5 is desired. The third control valve 72 is arranged on the water storage and outlet pipe 42, the fourth control valve 73 is arranged on a pipe section between the pure water pipeline 2 and the communication part of the pure water pipeline and the water storage and inlet pipe 41 and the water storage and outlet pipe 42, and whether the water finally flowing out of the pure water pipeline 2 flows through the water storage pipeline before flowing out is controlled through the third control valve 72 and the fourth control valve 73. A fifth control valve 74 is arranged in the displacement line for controlling whether the water in the plain water line 2 flows to the displacement line 5. A waste water valve 76 is provided in the waste water line 3 for controlling whether the waste water produced by the RO cartridge 81 can be discharged from the waste water line 3.

The water purifier still includes the pump body 84, pressure protection pipeline 6, the pump body 84 sets up on water inlet pipe 1 and the replacement pipeline 5 intercommunication department low reaches water inlet pipe 1, the one end and the waste water pipeline 3 of pressure protection pipeline 6 are linked together, the other end and the water inlet pipe 1 intercommunication department of pressure protection pipeline 6 are located between the low reaches of second TDS detection part 83 and the upper reaches of the pump body 84, control valve subassembly still includes sixth control valve 75, sixth control valve 75 sets up on pressure protection pipeline 6. The pump 84 is used to supply pressure to the concentrate side of the RO membrane in the RO cartridge 81 to cause the RO cartridge 81 to perform reverse osmosis to complete filtration. The pressure protection pipeline 6 is equivalent to the shunt before the pump, and plays a role in stabilizing pressure. If the water purifier starts the water production stage, the sixth control valve 75 is closed, the pressure of the inlet water is high, the partial pressure of the split water is not available, and the pressure is increased the longer the RO membrane in the RO cartridge 81 is used. The pressure protection pipeline 6 is a pressure protection system structure behind the pump, the pressure of water inflow can be reduced by opening the sixth control valve 75, the pipeline and the filter element are prevented from bursting due to overhigh pressure, and the system structure is more stable.

The water purifier further includes a pre-filter 85 and a post-filter 86, the pre-filter 85 is disposed on the water inlet line 1 and located upstream of the first control valve 70, and the post-filter 86 is disposed on the pure water line 2 and located upstream of a communication point where the pure water line 2 communicates with the substitution line 5 and downstream of the first TDS detecting member 82. The whole system is purified again before the user takes water, the water of the post-filter element 86 is also purified, and the water drunk by the user has no stale water completely.

The water purifier has a water making state and a replacement state, and is in the water making state: the first control valve 70 is opened, the second control valve 71 is opened, one of the third control valve 72 and the fourth control valve 73 is opened, the fifth control valve 74 is closed, the sixth control valve 75 is opened, and a user can drink water filtered by the RO cartridge 81; in the displaced state: the first control valve 70 is closed, the second control valve 71 is closed, the third control valve 72 is opened, the fourth control valve 73 is closed, the fifth control valve 74 is opened, the sixth control valve 75 is closed, and the water purifier filters the water on the concentrate side of the RO membranes in the replacement water storage unit 43 and the RO filter element 81 to reduce the TDS value thereof.

The water production state comprises a first water production state and a second water production state, and the states are switched by comparing the detection value of the first TDS detection component 82 with a set value, which is determined according to the water quality of different regions, and in the embodiment, the set value is 90.

When the detection value of the first TDS detecting part 82 is less than the set value, the water purifier is in a first water producing state: the first control valve 70 is opened, the second control valve 71 is opened, the third control valve 72 is opened, the fourth control valve 73 is closed, the fifth control valve 74 is closed, and the sixth control valve 75 is opened.

The specific working principle is as follows: the user opens the switch 87 or sends a signal to the control component by other remote control devices, the pump body 84 works, the raw water passes through the front filter element 85, the first control valve 70 is opened, the second TDS detection component 83 detects the TDS value of the inlet water in real time, the inlet water flows through the RO filter element 81, the third control valve 72 is opened, the fourth control valve 73 is closed, the pump body 84 ejects out the pure water in the RO filter element 81, the pure water flows through the replacement water storage component 43 full of the pure water, the outlet water passes through the rear filter element 86, the second control valve 71 is opened, the fifth control valve 74 is closed, the pure water flows out through the faucet, and the user drinks healthy water.

When the detection value of the first TDS detecting part 82 is greater than or equal to the set value, the water purifier is in a second water production state: the first control valve 70 is opened, the second control valve 71 is opened, the third control valve 72 is closed, the fourth control valve 73 is opened, the fifth control valve 74 is closed, and the sixth control valve 75 is opened.

The specific working principle is as follows: the user opens the switch 87 or sends a signal to the control part with other remote control unit, the pump body 84 works, the raw water passes through the leading filter core 85, the first control valve 70 is opened, the second TDS detects the TDS value that the part 83 detects the intaking in real time, the RO filter core 81 flows through, the third control valve 72 is closed, the fourth control valve 73 is opened, the pump body 84 is ejecting with the pure water in the RO filter core 81, the dense water of higher TDS value is accumulated in the water tank, the pure water in the RO filter core 81 directly flows through the trailing filter core 86, the second control valve 71 is opened, the fifth control valve 74 is closed, the pure water flows out through the tap, the user drinks healthy water.

The replacement water storage part 43 can adopt conventional parts such as a water tank, the material can be a PP material or a better environment-friendly material, a more environment-friendly novel material is selected, and secondary pollution can be avoided. The water inlet of the replacement water storage part 43 is connected with the water storage inlet pipe 41, the water outlet is connected with the water storage outlet pipe 42, the water inlet is arranged at the upper part, and the water outlet is arranged at the lower part. The displacement water storage part 43 has a volume equal to the pure water side volume of the RO membrane in the RO filter element 81, so that the displacement effect is good, in this embodiment, the pure water side volume of the RO membrane in the RO filter element 81 is about 250-300 mL, and the displacement water storage part 43 adopts a 250-mL water storage tank, and has no any air bag, leather bag and other accessories, so that the displacement water storage part does not occupy space, and bacteria are not easy to breed. Regularly detecting the internal pollution condition of the replacement water storage part 43, determining the cleaning period and eliminating the internal pollution; the replacement water storage member 43 has an automatic cleaning function.

After the water making is finished, the water making device enters a replacement state, and the specific working principle is as follows: the user closes the switch 87 or other remote control device to send a signal to the control component, the first control valve 70 and the second control valve 71 are closed, the waste water valve 76 is opened, the waste water produced by the RO filter element 81 is directly discharged through the waste water valve 76, the third control valve 72 is opened, the fourth control valve 73 is closed, the fifth control valve 74 is opened, the sixth control valve 75 is closed, the high TDS value concentrated water accumulated in the replacement water storage component 43 passes through the rear filter element 86, enters the replacement pipeline 5 and flows back to the front end of the pump body 84, the pump body 84 provides pressure to enable the concentrated water to be circularly filtered, the waste water is directly discharged, and the pure water enters the replacement water storage component 43 to be stored. The circulation time can be 3-5min, and is controlled by the control part and adjusted according to different raw water qualities and different RO filter elements 81. The membrane of the thick water survey of the RO membrane in the RO filter core 81 is flushed by the thick water in the internal circulation process, so that the burden of the membrane is reduced, and the service life of the membrane is prolonged. This embodiment replaces dense water through replacement water storage part 43 and carries out inside backward flow circulation, effectively reduces the TDS value, can also make the extension of filter core life-span.

The control valve assembly further includes a first check valve 77, a second check valve 78, and a third check valve 79 for ensuring the flow direction of the water path to avoid reverse flow. The first check valve 77 is provided on the pure water line 2 between the upstream of the communication between the pure water line 2 and the replacement line 5 and the downstream of the first TDS detecting part 82, the second check valve 78 is provided on the pure water line 2 between the downstream of the second control valve 71 and the upstream of the switch 87, and the third check valve 79 is provided on the replacement line 5 and the downstream of the fifth control valve 74.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A water purifier for preventing pure water TDS from rising comprises an RO filter element, a water inlet pipeline, a waste water pipeline, a pure water pipeline and a control valve component, wherein the water inlet pipeline and the waste water pipeline are communicated with the concentrated water side of an RO membrane in the RO filter element, the pure water pipeline is communicated with the pure water side of the RO membrane in the RO filter element, and the control valve component comprises a first control valve arranged on the water inlet pipeline and a second control valve arranged on the pure water pipeline, and is characterized in that:

the control valve assembly further comprises at least one of a third control valve and a fourth control valve and a fifth control valve, the third control valve is arranged on one of the water storage water inlet pipe and the water storage water outlet pipe, the fourth control valve is arranged on the pure water pipeline and a pipe section between the water storage water inlet pipe and the water storage water outlet pipe, and the fifth control valve is arranged on the replacement pipeline.

2. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the third control valve and the fourth control valve are arranged at the same time.

3. The water purifier preventing TDS increase of pure water according to claim 2, wherein: the water purifier has a water production state and a replacement state, and is in the water production state: the first control valve is opened, the second control valve is opened, one of the third control valve and the fourth control valve is opened, and the fifth control valve is closed; in the replacement state: the first control valve is closed, the second control valve is closed, the third control valve is opened, the fourth control valve is closed, and the fifth control valve is opened.

4. The water purifier preventing TDS increase of pure water according to claim 3, wherein: the water making state comprises a first water making state and a second water making state,

5. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the water purifier also comprises a control component, and the control component is connected with the first TDS detection component and the control valve component.

6. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the third control valve is arranged on the water storage and outlet pipe.

7. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the water purifier also comprises a pump body and a pressure protection pipeline, wherein the pump body is arranged on a water inlet pipeline at the downstream of the communication position of the water inlet pipeline and the displacement pipeline, one end of the pressure protection pipeline is communicated with the waste water pipeline, the other end of the pressure protection pipeline is communicated with the water inlet pipeline, the control valve component also comprises a sixth control valve, and the sixth control valve is arranged on the pressure protection pipeline.

8. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the water purifier also comprises a preposed filter element and/or a postposition filter element, wherein the preposed filter element is arranged on the water inlet pipeline at the upper stream of the communication position of the water inlet pipeline and the replacement pipeline, and the postposition filter element is arranged on the pure water pipeline at the upper stream of the communication position of the pure water pipeline and the replacement pipeline.

9. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the water purifier still include second TDS detects the part, second TDS detect the part setting be in the inlet line with the replacement pipeline intercommunication on the inlet line of department upper reaches.

10. The water purifier preventing TDS increase of pure water according to claim 1, wherein: the control valve assembly further comprises at least one of a first check valve, a second check valve and a third check valve, wherein the first check valve is arranged on a pure water pipeline at the upstream of the communication position of the pure water pipeline and the replacement pipeline, the second check valve is arranged on a pure water pipeline at the downstream of the communication position of the pure water pipeline and the replacement pipeline, and the third check valve is arranged on the replacement pipeline.