Electrodialysis membrane stack assembly and water purification system having the same

Abstract

The present invention discloses an electrodialysis membrane stack assembly and a water purification system having the same. The electrodialysis membrane stack assembly includes: an electrodialysis membrane stack, on which a first water inlet, a second water inlet, a purified water outlet and a concentrated water outlet are provided, the first water inlet is communicated with the purified water outlet, and the second water inlet is communicated with the concentrated water outlet; a switching device, which is switchable between a water production state and a flushing state, and the switching device reduces the flow rate entering the first water inlet in the flushing state. The electrodialysis membrane stack assembly according to the embodiments of the present invention has advantages such as high flushing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical appliance manufacturing, and more particularly, to an electrodialysis membrane stack assembly and a water purification system having the electrodialysis membrane stack assembly. Background Art

[0002] In the related art of electrodialysis water purification systems, the membrane stack needs to be flushed, but the flushing efficiency is low and the user waiting time is long. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides an electrodialysis membrane stack assembly, which has the advantages of high flushing efficiency and the like.

[0004] The present invention also provides a water purification system having the electrodialysis membrane stack assembly.

[0005] To achieve the above object, according to an embodiment of the first aspect of the present invention, an electrodialysis membrane stack assembly is provided, which includes: an electrodialysis membrane stack, on which a first water inlet, a second water inlet, a purified water outlet and a concentrated water outlet are provided, the first water inlet is communicated with the purified water outlet, and the second water inlet is communicated with the concentrated water outlet; a switching device, which is switchable between a water production state and a flushing state, and the switching device reduces the flow rate entering the first water inlet in the flushing state.

[0006] The electrodialysis membrane stack assembly according to the embodiment of the present invention has the advantages of high flushing efficiency and the like.

[0007] In addition, the electrodialysis membrane stack assembly according to the above embodiment of the present invention may further have the following additional technical features:

[0008] According to an embodiment of the present invention, the electrodialysis membrane stack assembly further includes: a water inlet pipe communicated with a water source; a first branch pipe connected to the water inlet pipe and the first water inlet; and a second branch pipe connected to the water inlet pipe and the second water inlet.

[0009] According to an embodiment of the present invention, the switching device includes: a first control valve connected to the first branch pipe to control the on-off of the first branch pipe, the first control valve is opened in the water production state of the switching device, and the first control valve is closed in the flushing state of the switching device.

[0010] According to an embodiment of the present invention, the switching device includes: a first control valve connected to the first branch pipe to control the opening degree of the first branch pipe. In the water production state, the first control valve of the switching device is at a first opening degree, and in the flushing state, the first control valve of the switching device is at a second opening degree, and the second opening degree is smaller than the first opening degree.

[0011] According to an embodiment of the present invention, the switching device further includes: a second control valve connected to the second branch pipe to control the on-off of the second branch pipe.

[0012] According to an embodiment of the present invention, both the first control valve and the second control valve are solenoid valves.

[0013] According to an embodiment of the present invention, the electrodialysis membrane stack includes: a membrane group including a cation exchange membrane and an anion exchange membrane arranged oppositely; an electrode group including a positive electrode plate and a negative electrode plate, the positive electrode plate is arranged on one side of the membrane group, and the negative electrode plate is arranged on the other side of the membrane group; a flow guiding plate including a first grid, a second grid and a third grid, the first grid is arranged between the negative electrode plate and the cation exchange membrane, the second grid is arranged between the cation exchange membrane and the anion exchange membrane, and the third grid is arranged between the anion exchange membrane and the positive electrode plate; a first pressing plate and a second pressing plate, the first pressing plate is pressed on the positive electrode plate, and the second pressing plate is pressed on the negative electrode plate.

[0014] According to an embodiment of the present invention, a first insulating partition is provided between the first pressing plate and the positive electrode plate, and a second insulating partition is provided between the second pressing plate and the negative electrode plate.

[0015] According to an embodiment of the present invention, a first flow channel connecting the first water inlet and the purified water outlet and a second flow channel connecting the second water inlet and the concentrated water outlet are formed on the flow guiding plate.

[0016] According to an embodiment of the second aspect of the present invention, a water purification system is provided, and the water purification system includes the electrodialysis membrane stack assembly according to the embodiment of the first aspect of the present invention.

[0017] The water purification system according to the embodiment of the present invention has advantages such as high flushing efficiency by using the electrodialysis membrane stack assembly according to the embodiment of the first aspect of the present invention.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 FIG. 5 is a schematic structural view of an electrodialysis membrane stack assembly according to an embodiment of the present invention.

[0021] Figure 2 FIG. 6 is a schematic structural view of an electrodialysis membrane stack of the electrodialysis membrane stack assembly according to an embodiment of the present invention.

[0022] Figure 3 FIG. 7 is an exploded view of the electrodialysis membrane stack of the electrodialysis membrane stack assembly according to an embodiment of the present invention.

[0023] Figure 4 FIG. 8 is an exploded view of the electrodialysis membrane stack of the electrodialysis membrane stack assembly according to an embodiment of the present invention.

[0024] Reference numerals: electrodialysis membrane stack assembly 1, electrodialysis membrane stack 10, first water inlet 11, second water inlet 12, purified water outlet 13, concentrated water outlet 14, cation exchange membrane 151, anion exchange membrane 152, positive electrode plate 161, negative electrode plate 162, first grid 171, second grid 172, third grid 173, first pressing plate 181, second pressing plate 182, first insulating partition 191, second insulating partition 192, first control valve 21, second control valve 22, water inlet pipe 31, first branch pipe 32, second branch pipe 33, purified water outlet pipe 41, concentrated water outlet pipe 42. Detailed Description of the Embodiments

[0025] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0026] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0027] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The electrodialysis membrane stack assembly 1 according to an embodiment of the present invention will be described below with reference to the drawings.

[0029] As Figures 1-4 shown, the electrodialysis membrane stack assembly 1 according to an embodiment of the present invention includes an electrodialysis membrane stack 10 and a switching device.

[0030] The electrodialysis membrane stack 10 is provided with a first water inlet 11, a second water inlet 12, a purified water outlet 13, and a concentrated water outlet 14. The first water inlet 11 is communicated with the purified water outlet 13, and the second water inlet 12 is communicated with the concentrated water outlet 14. The switching device is switchable between a water production state and a flushing state, and the switching device reduces the flow rate entering the first water inlet 11 in the flushing state.

[0031] Those skilled in the art can understand that "reducing the flow rate entering the first water inlet 11" includes, but is not limited to, reducing the flow rate to 0. In other words, it may include closing the first water inlet 11.

[0032] For example, when the electrodialysis membrane stack assembly 1 is producing water normally, the first water inlet 11 remains fully open to ensure the water production flow rate. When the electrodialysis membrane stack assembly 1 is being flushed, the opening degree of the first water inlet 11 is reduced, thereby reducing the flow rate at the first water inlet 11. At the same time, the flow rate of the second water inlet 12 is increased while the total water inlet volume remains unchanged, improving the flushing efficiency.

[0033] Or when the electrodialysis membrane stack assembly 1 is producing water normally, the first water inlet 11 is opened to ensure the water production flow rate. When the electrodialysis membrane stack assembly 1 is being flushed, the first water inlet 11 is closed to stop the water inlet of the first water inlet 11. At the same time, the flow rate of the second water inlet 12 is increased while the total water inlet volume remains unchanged, improving the flushing efficiency. And since the flushing water does not enter the electrodialysis membrane stack 10 through the first water inlet 11, it can prevent the flushing water from mixing with the purified water that has been prepared in the purified water channel, playing a role in retaining the prepared purified water and avoiding waste of water resources and energy.

[0034] The electrodialysis membrane stack assembly 1 according to the embodiment of the present invention, by setting the electrodialysis membrane stack 10, the electrodialysis membrane stack 10 has a high water recovery rate, is simple to operate, has a long membrane life, can operate at high temperatures, and has a strong resistance to acids and alkalis. It does not require a large amount of pretreatment and post-treatment, and can also facilitate the separation of polyvalent ions.

[0035] The inventors of the present application have found through a large amount of research that in the electrodialysis type purified water system in the related art, when flushing, the water at the water source flushes both the first water inlet 11 and the second water inlet 12 at the same time. Since the water flow rate at the first water inlet 11 is large, the flushing efficiency of the electrodialysis membrane stack assembly 1 is low, increasing the waiting time of the user.

[0036] The electrodialysis membrane stack assembly 1 according to the embodiment of the present invention, by setting the switching device, maintains the water production state when the electrodialysis membrane stack assembly 1 is producing water, thus ensuring the water outlet flow rate of the electrodialysis membrane stack assembly 1 and ensuring the water production efficiency. When the electrodialysis membrane stack assembly 1 is being flushed, it switches to the flushing state, reducing the flow rate at the first water inlet 11, making the water at the water source more concentrated in flushing the second water inlet 12, increasing the flow rate of the second water inlet 12. When the flow rate required for the same flushing effect is reached, the flushing time is reduced, thereby improving the flushing efficiency of the electrodialysis membrane stack assembly 1 and reducing the user's waiting time.

[0037] Therefore, the electrodialysis membrane stack assembly 1 according to the embodiment of the present invention has advantages such as high flushing efficiency.

[0038] Next, the electrodialysis membrane stack assembly 1 according to the specific embodiment of the present invention will be described with reference to the accompanying drawings.

[0039] In some specific embodiments of the present invention, as Figures 1-4 shown, the electrodialysis membrane stack assembly 1 according to the embodiment of the present invention includes an electrodialysis membrane stack 10 and a switching device.

[0040] Specifically, as Figure 1As shown, the electrodialysis membrane stack 10 further includes a water inlet pipe 31, a first branch pipe 32, and a second branch pipe 33. The water inlet pipe 31 is communicated with a water source. The first branch pipe 32 is connected to the water inlet pipe 31 and the first water inlet 11. The second branch pipe 33 is connected to the water inlet pipe 31 and the second water inlet 12. This can facilitate the diversion of water at the water source, so that the raw water enters the first water inlet 11 and the second water inlet 12 respectively.

[0041] In a specific embodiment of the present invention, as Figure 1 shown, the switching device includes a first control valve 21. The first control valve 21 is connected to the first branch pipe 32 to control the opening degree of the first branch pipe 32. When the switching device is in the water production state, the first control valve 21 is in a first opening degree. When the switching device is in the flushing state, the first control valve 21 is in a second opening degree, and the second opening degree is smaller than the first opening degree. This can use the first control valve 21 to reduce the opening degree of the first branch pipe 32 when flushing the electrodialysis membrane stack assembly 1, thereby increasing the flow rate of the second branch pipe 33 and improving the flushing efficiency of the electrodialysis membrane stack assembly 1.

[0042] Specifically, when the electrodialysis membrane stack assembly 1 is producing water normally, the first control valve 21 maintains the maximum opening degree to ensure the water production flow rate. When the electrodialysis membrane stack assembly 1 is being flushed, the opening degree of the first control valve 21 is reduced, thereby reducing the flow rate at the first water inlet 11. At the same time, when the total water inflow remains unchanged, the flow rate of the second water inlet 12 is increased, improving the flushing efficiency.

[0043] In a specific embodiment of the present invention, as Figure 1 shown, the switching device includes a first control valve 21. The first control valve 21 is connected to the first branch pipe 32 to control the on-off of the first branch pipe 32. When the switching device is in the water production state, the first control valve 21 is open. When the switching device is in the flushing state, the first control valve 21 is closed. This can use the first control valve 21 to close the first branch pipe 32 when flushing the electrodialysis membrane stack assembly 1, thereby increasing the flow rate of the second branch pipe 33 and improving the flushing efficiency of the electrodialysis membrane stack assembly 1.

[0044] In addition, since the flushing water does not enter the first water inlet 11 through the first branch pipe 32, the purified water already prepared in the net water flow channel of the electrodialysis membrane stack assembly 1 will not be mixed and replaced by the flushing water, thereby protecting the prepared purified water and reducing the waste of water resources and energy.

[0045] Specifically, when the electrodialysis membrane stack assembly 1 is producing water normally, the first control valve 21 is opened to ensure the water production flow rate. When the electrodialysis membrane stack assembly 1 is being flushed, the first control valve 21 is closed, thereby disconnecting the first branch pipe 32, stopping the water inlet at the first water inlet 11, and at the same time increasing the flow rate of the second water inlet 12 while keeping the total water inlet volume unchanged, improving the flushing efficiency. And since the flushing water does not enter the electrodialysis membrane stack 10 through the first water inlet 11, it can prevent the flushing water from mixing with the purified water already prepared in the purified water channel, serving to retain the prepared purified water and avoid wasting water resources and energy.

[0046] More specifically, as Figure 1 shown, the switching device further includes a second control valve 22. The second control valve 22 is connected to the second branch pipe 33 to control the on-off of the second branch pipe 33. This can further facilitate the control of the water path of the electrodialysis membrane stack assembly 1.

[0047] Of course, the second control valve 22 can also be used to control the opening degree of the second branch pipe 33.

[0048] Optionally, both the first control valve 21 and the second control valve 22 are solenoid valves. This can facilitate the control of the first control valve 21 and the second control valve 22.

[0049] Figures 2-4 Figure 15 shows the electrodialysis membrane stack assembly 1 according to a specific example of the present invention. As Figures 2-4 shown, the electrodialysis membrane stack 10 includes a membrane group, an electrode group, a flow guide plate, a first pressing plate 181, and a second pressing plate 182. The membrane group includes a cation exchange membrane 151 and an anion exchange membrane 152 arranged oppositely. The electrode group includes a positive electrode plate 161 and a negative electrode plate 162. The positive electrode plate 161 is provided on one side of the membrane group, and the negative electrode plate 162 is provided on the other side of the membrane group. The flow guide plate includes a first grid 171, a second grid 172, and a third grid 173. The first grid 171 is provided between the negative electrode plate 162 and the cation exchange membrane 151, the second grid 172 is provided between the cation exchange membrane 151 and the anion exchange membrane 152, and the third grid 173 is provided between the anion exchange membrane 152 and the positive electrode plate 161. The first pressing plate 181 is press-connected to the positive electrode plate 161, and the second pressing plate 182 is press-connected to the negative electrode plate 162. This can facilitate the setting of the electrodialysis membrane stack 10. By press-connecting pressing plates on the sides of the positive electrode plate 161 and the negative electrode plate 162 away from the membrane group respectively, a stable pre-pressure can be continuously applied to the membrane group, the electrode group, and the flow guide plate, ensuring the long-term operation of the electrodialysis membrane stack 10, reducing the risk of water leakage, and improving the reliability of the electrodialysis membrane stack 10.

[0050] Advantageously, as Figures 2-4As shown, a first insulating partition 191 is provided between the first pressing plate 181 and the positive electrode plate 161, and a second insulating partition 192 is provided between the second pressing plate 182 and the negative electrode plate 162. The insulating partitions are used to prevent the positive electrode plate 161 or the negative electrode plate 162 from leaking electricity to the outside during use. By isolating the positive electrode plate 161 and the negative electrode plate 162 from the outside through the insulating partitions, the reliability of the electrodialysis membrane stack 10 is effectively improved.

[0051] Those skilled in the art can understand that the first pressing plate 181 and the second pressing plate 182 can also be set as insulating parts to achieve the insulating effect. Specifically, the first pressing plate 181 and the second pressing plate 182 can be fiber pressing plates. Preferably, they are epoxy resin carbon fiber pressing plates and glass fiber reinforced nylon pressing plates. The fiber pressing plates have a smaller density and lighter weight.

[0052] Specifically, the first pressing plate 181 and the second pressing plate 182 can be connected by bolts and nuts. By tightening the bolts and nuts, it is convenient for the pressing plates to press the membrane stack tightly.

[0053] Specifically, as Figure 3 and Figure 4 shown, a first flow channel communicating the first water inlet 11 and the purified water outlet 13 and a second flow channel communicating the second water inlet 12 and the concentrated water outlet 14 are formed on the flow guiding plate. This can facilitate the formation of the purified water flow channel and the concentrated water flow channel, and facilitate the smooth diversion of the purified water and the concentrated water.

[0054] Specifically, through holes penetrating the thickness are provided on the cation exchange membrane 151, the anion exchange membrane 152, the positive electrode plate 161, the negative electrode plate 162, the first grid 171, the second grid 172, the third grid 173, the first pressing plate 181, the second pressing plate 182, the first insulating partition 191, and the second insulating partition 192. Grid flow channels communicating with their respective through holes are provided on the first grid 171, the second grid 172, and the third grid 173.

[0055] The sizes of the cation exchange membrane 151, the anion exchange membrane 152, the positive electrode plate 161, the negative electrode plate 162, the first grid 171, the second grid 172, and the third grid 173 can be the same and smaller than the sizes of the first pressing plate 181, the second pressing plate 182, the first insulating partition 191, and the second insulating partition 192.

[0056] When the electrodialysis membrane stack 10 works, water enters the electrodialysis membrane stack 10 from the water inlet pipe 31, the first water inlet 11, and the second water inlet 12. After the electrodialysis membrane stack 10 is pressed tightly, the raw water entering the membrane stack flows through the pores and grid flow channels inside the membrane stack.

[0057] Water from the first water inlet 11 can pass through the pore channels and successively pass through the second pressing plate 182, the second insulating partition 192, the first grid 171, and the anion exchange membrane 152 to reach the second grid 172. Raw water cannot directly pass through the anion exchange membrane 152 and the third grid 173, and can only flow downward through the second grid 172 to the bottom holes of the second grid 172, and then successively pass through the anion exchange membrane 152, the third grid 173, the positive electrode plate 161, the first insulating partition 191, and the first pressing plate 181 and flow out through the purified water outlet 13. The water in this water passage is purified water.

[0058] Water from the second water inlet 12 can pass through the pore channels and successively pass through the second pressing plate 182, the second insulating partition 192, the first grid 171, and the anion exchange membrane 152 to reach the second grid 172. Raw water cannot directly pass through the anion exchange membrane 152 and the third grid 173, and can only flow downward through the second grid 172 to the bottom holes of the second grid 172, and then successively pass through the anion exchange membrane 152, the third grid 173, the positive electrode plate 161, the first insulating partition 191, and the first pressing plate 181 and flow out through the concentrated water outlet 14. The water in this water passage is concentrated water.

[0059] In summary, in order to ensure the service life of the electrodialysis membrane stack assembly 1, it is necessary to flush the electrodialysis membrane stack 10. In the electrodialysis type purified water system in the related art, when the electrodialysis membrane stack 10 is flushed, the inlet water flushes both the concentrated water inlet and the fresh water inlet. When the inlet water flow rate is constant, the flushing speed of flushing both pipelines at the same time is slow, and the fresh water that has been obtained in the membrane stack will become tap water with a higher TDS again. In the present invention, the first control valve 21 closes the first branch pipe 32 during flushing, and only flushes the concentrated water side of the second water inlet 12, which improves the cleaning efficiency of the electrodialysis membrane stack 10, and at the same time well retains the separated fresh water in the electrodialysis membrane stack 10.

[0060] Specifically, when the electrodialysis membrane stack assembly 1 is working, both the first control valve 21 and the second control valve 22 are fully opened, and the first water inlet 11 and the second water inlet 12 simultaneously admit water, so that both the fresh water pipeline and the concentrated water pipeline admit water to ensure normal water use by users and concentrated water discharge.

[0061] When the electrodialysis membrane stack assembly 1 is cleaned, first close the first control valve 21, so that the flushing water does not enter the fresh water pipeline, ensuring that it will not be contaminated by tap water during cleaning. The flushing water only flows into the second branch pipe 33 and the second water inlet 12, and only flushes the concentrated water pipeline, flushing out the concentrated water as soon as possible, greatly shortening the cleaning time and improving the cleaning efficiency.

[0062] For example, when the electrodialysis membrane stack assembly 1 is operating, both solenoid valves are opened to ensure the use of fresh water and the discharge of concentrated water. When the membrane stack is being cleaned, there is no voltage on both sides of the electrodialysis membrane stack 10. At this time, the first control valve 21 is closed, the second control valve 22 is turned on, and the influent flow rate is set to 1500 mL / min.

[0063] Experiments show that at 7 seconds, the TDS of the outlet of the concentrated water outlet 14 is the same as the influent TDS of the second influent port 12.

[0064] When using the method of flushing with the first influent port 11 and the second influent port 12 simultaneously, with the total influent flow rate remaining unchanged, it takes about 15 seconds for the TDS of the effluent of the electrodialysis membrane stack 10 to reach the same as the influent TDS.

[0065] Specifically, to ensure the flushing effect and reduce the waiting time for users, the flushing time can be less than or equal to 1 minute.

[0066] The water purification system according to an embodiment of the present invention will be described below. The water purification system according to an embodiment of the present invention includes the electrodialysis membrane stack assembly 1 according to the above embodiment of the present invention.

[0067] The water purification system according to an embodiment of the present invention, by utilizing the electrodialysis membrane stack assembly 1 according to the above embodiment of the present invention, has advantages such as healthy water use and not being prone to bacteria growth.

[0068] Other components and operations of the water purification system according to an embodiment of the present invention are known to those of ordinary skill in the art and will not be described in detail here.

[0069] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0070] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An electrodialysis membrane stack assembly, characterized in that, Comprising: An electrodialysis membrane stack, on which there are a first water inlet, a second water inlet, a purified water outlet and a concentrated water outlet, the first water inlet being communicated with the purified water outlet, and the second water inlet being communicated with the concentrated water outlet; A switching device, which is switchable between a water production state and a flushing state, and the switching device reduces the flow rate into the first water inlet in the flushing state; A water inlet pipe, which is communicated with a water source; A first branch pipe, which is connected to the water inlet pipe and the first water inlet; A second branch pipe, which is connected to the water inlet pipe and the second water inlet; The switching device includes a first control valve and a second control valve. The first control valve is connected to the first branch pipe to control the on-off or opening degree of the first branch pipe, and the second control valve is connected to the second branch pipe to control the on-off of the second branch pipe. The first control valve of the switching device is opened in the water production state, and the first control valve of the switching device is closed or its opening degree is reduced in the flushing state, so as to increase the flow rate of the second water inlet under the condition that the total water inlet amount remains unchanged.

2. The electrodialysis membrane stack assembly according to claim 1, wherein The switching device includes: The first control valve of the switching device is at a first opening degree in the water production state, and the first control valve of the switching device is at a second opening degree in the flushing state, and the second opening degree is smaller than the first opening degree.

3. The electrodialysis membrane stack assembly according to claim 1, wherein Both the first control valve and the second control valve are solenoid valves.

4. The electrodialysis membrane stack assembly according to claim 1, characterized in that The electrodialysis membrane stack includes: A membrane group, which includes a cation exchange membrane and an anion exchange membrane arranged oppositely; An electrode group, which includes a positive electrode plate and a negative electrode plate. The positive electrode plate is arranged on one side of the membrane group, and the negative electrode plate is arranged on the other side of the membrane group; A flow guiding plate, which includes a first grid, a second grid and a third grid. The first grid is arranged between the negative electrode plate and the cation exchange membrane, the second grid is arranged between the cation exchange membrane and the anion exchange membrane, and the third grid is arranged between the anion exchange membrane and the positive electrode plate; A first pressing plate and a second pressing plate, the first pressing plate being pressed on the positive electrode plate, and the second pressing plate being pressed on the negative electrode plate.

5. The electrodialysis membrane stack assembly according to claim 4, wherein, A first insulating partition is arranged between the first pressing plate and the positive electrode plate, and a second insulating partition is arranged between the second pressing plate and the negative electrode plate.

6. The electrodialysis membrane stack assembly according to claim 4, wherein, A first flow channel communicating the first water inlet and the purified water outlet and a second flow channel communicating the second water inlet and the concentrated water outlet are formed on the flow guiding plate.

7. A water purification system, characterized in that, Including the electrodialysis membrane stack assembly according to any one of claims 1-6.

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