A reverse osmosis membrane filter cartridge, a water purification device and a control method thereof

Abstract

The application discloses a kind of reverse osmosis membrane filter element, water purification equipment and its control method, reverse osmosis membrane filter element includes membrane shell, center tube, reverse osmosis membrane, elastic component and adapter, elastic component is arranged in center tube, when normal water preparation, pure water is gathered from the membrane pure water outlet of the pipe wall of center tube and flows out through the pure water outlet of the end of center tube, when closing faucet, booster pump continues to run until reaching set water pressure, elastic component is compressed and generates elastic force, continue to generate pure water is stored in center tube, when shutdown, elastic force reversely drives elastic component to move, and pure water in center tube is reversely pressed into reverse osmosis membrane, and raw water in membrane, concentrated water is discharged through concentrated water port, not only reduce the TDS value of first cup water when water preparation again, also have the advantages that structure is simple, small, low in cost and water consumption is less.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water purification, in particular, relates to a reverse osmosis membrane filter core, a water purification device and a control method thereof. BACKGROUND

[0002] With the increasing environmental pollution and water pollution, people's drinking water health has been seriously threatened. The RO (reverse osmosis) water purification technology is a good way to obtain pure water because it can remove various harmful impurities, heavy metals, viruses, bacteria and the like in water with high efficiency and thorough removal.

[0003] However, due to the characteristics of the RO membrane itself, the water before the membrane and the water after the membrane tend to approach through ion diffusion TSD after standing for a period of time, resulting in a high TDS of the first cup of pure water. In the prior art, in order to reduce the TDS value of the first cup of pure water, the following methods are usually used: 1. storing the raw water or the prepared pure water in a storage tank to clean the RO filter core with the water in the storage tank; 2. cleaning the RO filter core with the water filtered by an auxiliary filter core; 3. starting the filter core for a period of time before using the water purifier to prepare water, and discharging the water with a high TDS value first.

[0004] In the above methods, the cost of the water purification device is increased, the product size is too large, or the waiting time of the user is increased, which are not conducive to the promotion of the product. SUMMARY

[0005] The purpose of the present application is to provide a reverse osmosis membrane filter core, a water purification device and a control method thereof. An elastic component is arranged in the center pipe of the reverse osmosis membrane filter core. The pure water stored in the center pipe after the faucet is closed is backwashed to the reverse osmosis membrane by pressure driving, and the raw water and the concentrated water are replaced. The problem of high TDS value of the first cup of pure water is solved by the reverse osmosis filter core with simple structure, low cost and small water consumption.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] A reverse osmosis membrane filter core is provided, comprising: a membrane shell; a center pipe arranged in the membrane shell, one end of which is blocked and the other end of which is open to form a pure water outlet; a membrane pure water outlet is formed on the pipe wall of the center pipe; a reverse osmosis membrane is arranged around the center pipe, two end faces of the reverse osmosis membrane form a raw water inlet end face and a concentrated water outlet end face respectively, and a raw water cavity is formed between the circumferential surface of the reverse osmosis membrane and the membrane shell; further comprising: an elastic component installed in the center pipe, one end of which is fixed to the blocked end of the center pipe; the membrane pure water outlet is formed on the pipe wall of the non-elastic component containing part; an adapter is composed of a coaxial first sleeve and a circular ring part, the circular ring part abuts against the concentrated water outlet end face of the reverse osmosis membrane, and the first sleeve is sleeved outside the center pipe to form a concentrated water outlet passage between the first sleeve and the outer wall of the center pipe.

[0008] Further, the elastic component has a length greater than or equal to half of the length of the central tube.

[0009] Further, the elastic component comprises a spring fixed at one end of the blocking end of the central tube and a piston connected to the other end of the spring.

[0010] Further, the elastic component is a rubber capsule pre-filled with gas.

[0011] Further, the adapter further comprises a second sleeve vertically sleeved on the circumferential surface of the reverse osmosis membrane.

[0012] Further, the reverse osmosis membrane filter core further comprises a membrane cover provided with a raw water hole, a concentrated water hole and a pure water hole, the raw water hole being in communication with the raw water cavity, the concentrated water hole being in communication with the concentrated water outlet channel, and the pure water hole being in communication with the pure water outlet.

[0013] Further, a first limiting structure is arranged on the wall of the central tube above the membrane pure water outlet, for limiting the maximum stroke of the elastic component.

[0014] Further, a second limiting structure is extended from the position of the membrane shell opposite to the blocking end of the central tube, and the blocking end of the central tube is limited in the second limiting structure.

[0015] The application provides a water purification device comprising the reverse osmosis membrane filter core.

[0016] The application provides a control method of the water purification device, wherein a pressure switch is arranged at the pure water outlet of the water purification device, the method comprising: controlling the booster pump to continue running when the faucet of the water purification device is closed; receiving the detection signal of the pressure switch to determine the water pressure of the pure water outlet; and closing the booster pump when the water pressure reaches the set water pressure.

[0017] Compared with the prior art, the reverse osmosis membrane filter core, the water purification device and the control method thereof have the following advantages and positive effects: the elastic component is arranged in the central tube of the reverse osmosis membrane filter core, the pure water is collected from the membrane pure water outlet arranged on the wall of the central tube and flows out from the pure water outlet at the end of the central tube when normal water is produced, the booster pump continues to run until the set water pressure is reached when the faucet is closed, the elastic component is compressed and generates elastic force, so that the pure water produced continuously is stored in the central tube, the storage amount of the pure water is increased, and the elastic force reversely drives the elastic component to move when the machine is stopped, so that the pure water in the central tube is reversely pressed into the reverse osmosis membrane through the membrane pure water outlet, the raw water and the concentrated water in the membrane are discharged through the concentrated water outlet, and the TDS value of the pure water is not greatly affected even if the raw water in front of the membrane permeates to the back of the membrane during the shutdown of the machine, so that the effect of reducing the TDS value of the first cup of water when water is produced again is achieved.

[0018] Further, the length of the elastic assembly is set to be greater than or equal to half of the length of the central tube, the longer the length, the more pure water is back-flushed from the reverse osmosis membrane, the better the flushing effect on the reverse osmosis membrane, and the less pure water remains after shutdown, which makes the pure water flowing out after the next start mostly newly prepared pure water, so that the influence of the pure water permeated from the raw water during shutdown on the TDS value can be ignored.

[0019] Further, compared with the prior art of adding a storage tank and an auxiliary filter element, the reverse osmosis filter element has the advantages of simple structure, small size and low cost, and has the advantage of small water consumption compared with the prior art of discharging water with a high TDS value first after starting for a period of time.

[0020] Other features and advantages of the present application will become more apparent after reading the detailed description of the embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Water production state diagram of the reverse osmosis membrane filter element proposed in the present application;

[0022] Figure 2 Water stop state diagram of the reverse osmosis membrane filter element proposed in the present application;

[0023] Figure 3 Back-flushing state diagram of the reverse osmosis membrane filter element proposed in the present application;

[0024] Figure 4 Structure diagram of the adapter in the reverse osmosis membrane filter element proposed in the present application;

[0025] Figure 5 Structure diagram of the raw water channel, the concentrated water outlet channel and the pure water outlet in the reverse osmosis membrane filter element proposed in the present application

[0026] Figure 6 Structure diagram of the membrane cover in the reverse osmosis membrane filter element proposed in the present application;

[0027] Figure 7 Another structure diagram of the membrane cover in the reverse osmosis membrane filter element proposed in the present application;

[0028] Figure 8 Architecture diagram of the water purification equipment proposed in the present application;

[0029] Figure 9 Flowchart of the water purification equipment control method proposed in the present application. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a thorough understanding of the present application. The present embodiments are described as examples only, and it is contemplated that the application has applicability outside the specific embodiments described herein.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0033] The present application aims to provide a reverse osmosis membrane filter element, which is provided with an elastic assembly in the center tube of the reverse osmosis membrane filter element, and the pure water stored in the center tube after the faucet is closed by pressure driving is used to backwash the reverse osmosis membrane, and the raw water and concentrated water are replaced, so that the problem of high TDS value of the first cup of pure water is solved by the reverse osmosis filter element with simple structure, low cost and small water consumption.

[0034] As shown in Figures 1 to 3 The reverse osmosis membrane filter element provided by the present application comprises a membrane shell 1, a center tube 2, a reverse osmosis membrane 3, an elastic assembly 4 and an adapter 5.

[0035] The center tube 2 is arranged in the membrane shell 1, one end of which is blocked, and the other end of which is open to form a pure water outlet 21, and a membrane pure water outlet 22 is formed on the wall of the center tube 2.

[0036] The reverse osmosis membrane 3 is arranged around the center tube 2, and two end faces of the reverse osmosis membrane 3 form a raw water inlet end face 31 and a concentrated water outlet end face 32, respectively, and a circumferential surface of the reverse osmosis membrane 3 and the membrane shell 1 form a raw water cavity 6, which is in the shape of a circular ring in cross section; the blocked end of the center tube 2 is higher than the raw water inlet end face 31 of the reverse osmosis membrane 3, and a cavity 61 is formed between the raw water inlet end face 31 and the inside of the membrane shell 1, which is in communication with the raw water cavity 6 to form a complete raw water passage; the open end of the center tube 2 extends out of the concentrated water outlet end face 32 of the reverse osmosis membrane 3.

[0037] A second limiting structure 11 is extended in the position opposite to the blocked end of the center tube 2 in the inside of the membrane shell 1, and the blocked end of the center tube 2 is limited in the second limiting structure 11 to prevent the center tube 2 from being inclined and / or misaligned.

[0038] The elastic assembly 4 is installed in the center tube 2, one end of which is fixed to the blocked end of the center tube 2; and the membrane pure water outlet 22 is formed on the wall of the center tube 2 in the part not accommodating the elastic assembly 4.

[0039] As shown in Figure 4 The adapter 5 is composed of a coaxial first sleeve 51 and a circular ring part 52, and the first sleeve 51 is connected to the circular ring part 52. Figure 1As shown, the circular ring part 52 abuts against the concentrated water outlet end surface 32 of the reverse osmosis membrane 3, and the first sleeve 51 is sleeved on the outer periphery of the central pipe 2 to form the concentrated water outlet channel 8 between the outer wall of the central pipe 2 and the inner wall of the membrane shell 1, and to form the raw water channel 7 between the outer wall of the central pipe 2 and the inner wall of the membrane shell 1. Figure 5 As shown, the pure water outlet 21, the concentrated water outlet channel 8 and the raw water channel 7 are in a circular ring distribution structure with different radii.

[0040] In some embodiments of the present application, the adapter 5 further comprises a second sleeve 53 with a vertical circular ring part 52 sleeved on the circumferential surface of the reverse osmosis membrane 3; the second sleeve 53 limits the reverse osmosis membrane 3.

[0041] Based on the reverse osmosis membrane filter element proposed above, when water production starts, the raw water flows to the cavity 61 through the raw water channel 7 and the raw water cavity 6, reaches the raw water inlet end surface 31 of the reverse osmosis membrane 3, enters the reverse osmosis membrane 3 from the raw water inlet end surface 31, the reverse osmosis membrane 3 filters the raw water, the pure water formed flows into the central pipe 2 from the membrane pure water outlet 22, and then flows out through the pure water outlet 21; the concentrated water filtered by the reverse osmosis membrane 3 flows into the concentrated water outlet channel 8 from the concentrated water outlet end surface 32 of the reverse osmosis membrane 3.

[0042] When the faucet of the water purification device is closed, the booster pump of the water purification device is controlled to continue running for a certain period of time or continues running for a certain period of time under the action of inertia, during which the pure water produced by the reverse osmosis membrane 3 stays in the central pipe 2 and squeezes the elastic assembly 4 because it cannot flow out.

[0043] After the elastic assembly 4 is squeezed to meet certain conditions, for example, the water pressure reaches a set value or is squeezed to the maximum compression stroke, the booster pump of the water purification device is stopped, and after the water production is stopped, the pure water in the central pipe 2 is pushed by the reverse force of the elastic assembly 4, flows back to the reverse osmosis membrane 3 from the membrane pure water outlet 22, and then the concentrated water and the raw water in the reverse osmosis membrane 3 are pressed out from the concentrated water outlet end surface 32, so as to realize the reverse flushing of the reverse osmosis membrane 3, and the reverse osmosis membrane 3 is soaked in pure water.

[0044] In some embodiments of the present application, the length of the elastic assembly 4 is designed to be greater than or equal to half of the length of the central pipe, and higher than the concentrated water outlet end surface 32 of the reverse osmosis membrane 3, and the membrane pure water outlet 22 is arranged on the wall of the central pipe between the end of the elastic assembly 4 and the concentrated water outlet end surface 32 of the reverse osmosis membrane 3, and a first limiting structure is arranged on the wall of the central pipe above the membrane pure water outlet 22 to limit the maximum stroke of the elastic assembly 4.

[0045] The longer the elastic component 4 is, the greater the degree of deformation after being squeezed. The more pure water is stored in the central tube after shutdown, the better the flushing effect on the reverse osmosis membrane 3, and the less pure water remains after shutdown. This means that most of the pure water flowing out when restarting is newly prepared pure water, and the impact of the pure water that permeates with the raw water during shutdown on the TDS value can be ignored.

[0046] In this invention, the elastic component 4 can be as follows: Figures 1 to 3 The assembly shown consists of a spring 41 and a piston 42, wherein one end of the spring 41 is fixed to the sealing end of the central tube 2, and the other end, i.e. the end, is connected to the piston 42.

[0047] The elastic component 4 can be a capsule pre-filled with a certain amount of gas. After the tap is turned off, the pure water prepared enters the central tube 3 and squeezes the capsule. After the booster pump stops, the pure water is squeezed into the reverse osmosis membrane 3 by the reverse tension of the capsule, and the reverse osmosis membrane 3 is backwashed, so that the reverse osmosis membrane 3 is soaked in pure water.

[0048] However, it is not limited to the embodiments of the present invention. It can be achieved by any component that can achieve sealing and form reverse elasticity or pressure. The overall length of the elastic component 4 is greater than or equal to half the length of the central tube 2, so as to ensure that the elastic force generated when it is compressed is sufficient to back-pressure the pure water back onto the reverse osmosis membrane 3.

[0049] like Figure 6 and Figure 7 As shown, the reverse osmosis membrane filter element proposed in this invention also includes a membrane cover 9 for sealing the open end of the membrane housing 1; the membrane cover is provided with a raw water hole 91, a concentrate hole 92 and a pure water hole 93. Based on the water circuit transfer structure, the raw water hole 91 can be connected to the raw water chamber 6, the concentrate outlet 92 can be connected to the concentrate outlet channel 8, and the pure water hole 93 can be connected to the pure water outlet 21.

[0050] The reverse osmosis membrane filter element proposed in this invention has the advantages of simple structure, small size and low cost compared with the existing technology of adding storage tanks and auxiliary filter elements. Compared with the existing filter element method of discharging water with high TDS value first after a period of time, it also has the advantage of low water consumption.

[0051] The following is combined Figures 1 to 3 as well as Figure 8 The working principle of the reverse osmosis membrane filter element proposed in this invention is described in detail.

[0052] The reverse osmosis membrane filter element proposed in this invention is applied to, for example... Figure 8 The water purification device shown includes a pre-filter 91, an inlet valve 92, a booster pump 93, the aforementioned reverse osmosis membrane filter, a wastewater valve 94, a one-way valve 95, a pressure switch 96, a post-filter 97, and a faucet 98.

[0053] Based on this water purification equipment, its control method is proposed, such as... Figure 9 As shown.

[0054] Step S91: When the tap of the water purifier is closed, control the booster pump to continue running.

[0055] like Figure 1 As shown, during normal water production, when the faucet 98 is turned on, the controller of the water purification equipment detects the pressure change of the pressure switch 96 and opens the inlet valve 92. The raw water enters the pre-filter 91 from the inlet pipe for primary filtration. The filtered purified water is then pressurized into the reverse osmosis membrane filter by the booster pump 93.

[0056] The purified water filtered by the pre-filter 91, which is also the raw water of the reverse osmosis membrane filter (hereinafter referred to as raw water), moves along the raw water channel 7 and the raw water chamber 6 towards the sealed end of the central tube 2, enters the cavity 61, and then enters the reverse osmosis membrane 3 from the raw water inlet end face 31. After being filtered by the reverse osmosis membrane 3, the pure water is collected from the membrane pure water outlet 22 opened on the tube wall of the central tube 2 and flows out through the pure water outlet 21 at the end of the central tube 2, so that the user obtains the prepared pure water; the concentrated water enters the concentrated water outlet channel 8 from the concentrated water outlet end face 32 of the reverse osmosis membrane 3, the wastewater valve 94 is opened, and the concentrated water is discharged from the wastewater pipeline; during this period, the elastic component 4 is in the natural state and the end is in position A.

[0057] When the tap 98 of the water purifier is turned off, the pure water outlet 22 is closed, and the booster pump 93 continues to operate.

[0058] Step S92: Receive the detection signal from the pressure switch to determine the water pressure at the pure water outlet.

[0059] During continuous operation of booster pump 93, raw water continues to enter the reverse osmosis membrane filter element. The reverse osmosis membrane 3 continues to filter pure water. The pure water produced cannot flow out of the pure water outlet passage and accumulates in the central tube 2, squeezing the elastic component 4. Under the action of water pressure, the elastic component 4 is compressed, and the pure water is stored in the space created by the compression of the elastic component 4 in the central tube 2. Figure 2 As shown.

[0060] During the compression of the elastic component 4, the water pressure in the pure water outlet passage gradually increases. The present invention continuously detects the pressure signal of the pressure switch 96 and determines the water pressure at the pure water outlet of the water purification equipment based on the pressure signal.

[0061] Step S93: When the water pressure reaches the set water pressure, turn off the booster pump.

[0062] like Figure 3 As shown, when the water pressure reaches the set water pressure, the elastic component 4 is compressed until position B, the booster pump 93 is turned off, and pure water is stored in the central pipe 2.

[0063] After the water purification device is stopped, the elastic component 4 drives the pure water in the center pipe 2 to be reversely pressed into the reverse osmosis membrane 3 through the pure water outlet 22 of the membrane, and the raw water and concentrated water in the reverse osmosis membrane 3 are discharged from the concentrated water outlet end surface 31 until the elastic component 4 returns to the natural state without elastic force, the pressure drop in the reverse osmosis membrane 3 is zero, and the elastic component 4 returns to the position A.

[0064] It can be seen that the reverse osmosis membrane filter element provided in the application can discharge the raw water and concentrated water in the reverse osmosis membrane through the backflow of the pure water stored in the center pipe 2 after the water purification device is stopped, thereby reducing the TDS value of the first cup of water when water is prepared again. Compared with the existing technology of adding a storage tank and an auxiliary filter element, the reverse osmosis membrane filter element has the advantages of simple structure, small size and low cost. Compared with the existing filter element which discharges water with a high TDS value first after starting for a period of time, the reverse osmosis membrane filter element has the advantage of small water consumption.

[0065] Of course, the application is not limited to the embodiments provided in the application. In actual application, the booster pump 93 can continue to operate for a period of time based on inertia after the faucet 98 is closed. Therefore, the control mode of controlling the booster pump 93 to continue to operate after the faucet 98 is closed and detecting the pressure signal of the pressure switch 96, and then controlling the booster pump 93 to stop operating when the water pressure reaches the set water pressure can be omitted, and a simple mode of preparing pure water based on the inertial operation of the booster pump and storing the pure water in the center pipe 2 can be used.

[0066] Specifically, in step S91, when the faucet of the water purification device is closed, the booster pump 93 is also closed immediately according to the existing control means, and steps S92 and S93 are omitted.

[0067] After the booster pump 93 is closed, the booster pump 93 continues to operate based on inertia. During the operation, the pure water prepared by the reverse osmosis membrane filter element is stored in the center pipe 2 and presses the elastic component 4. After the inertial operation of the booster pump 93 stops, the stored pure water is reversely pressed into the reverse osmosis membrane 3 under the action of the elastic force of the elastic component 4, the reverse osmosis membrane 3 is reversely flushed, and finally immersed in the pure water.

[0068] The mode of reversely flushing the reverse osmosis membrane based on the inertial operation of the booster pump can estimate the water preparation amount according to the duration of the inertial operation of the booster pump, and then estimate the occupied space of the pure water prepared during the inertial operation in the center pipe, so as to determine the length and / or compression performance of the elastic component 4, so that the elastic component 4 can meet the condition of reverse flushing after the inertial operation of the booster pump stops.

[0069] The reverse osmosis membrane filter element, water purification equipment and control method thereof have the following advantages: the elastic assembly is arranged in the center pipe of the reverse osmosis membrane filter element; when normal water is produced, pure water is collected from the membrane pure water outlet arranged on the pipe wall of the center pipe and flows out through the pure water outlet at the end of the center pipe; when the faucet is closed, the booster pump continues to operate until the set water pressure is reached, the elastic assembly is compressed and generates elastic force, so that the continuously produced pure water is stored in the center pipe, the storage amount of the pure water is increased, and after shutdown, the elastic force reversely drives the elastic assembly to move, the pure water in the center pipe is reversely pressed into the reverse osmosis membrane through the membrane pure water outlet, and the raw water and concentrated water in the membrane are discharged through the concentrated water outlet; during shutdown, even if the raw water before the membrane penetrates to the back of the membrane, the influence on the TDS value of the pure water is small, and the effect of reducing the TDS value of the first cup of water when water is produced again is achieved.

[0070] It should be pointed out that the above description is not a limitation of the present application, and the present application is not limited to the above examples only. Changes, modifications, additions or replacements made by ordinary skilled in the art within the essential scope of the present application shall also fall within the protection scope of the present application.

Claims

1. A reverse osmosis membrane filter cartridge, comprising: a membrane shell; a center tube arranged in the membrane shell, one end of which is closed and the other end of which is open to form a pure water outlet; a membrane pure water outlet is formed on the wall of the center tube; a reverse osmosis membrane arranged around the center tube, two end faces of which form a raw water inlet end face and a concentrated water outlet end face respectively, and a raw water cavity is formed between the circumferential surface of the reverse osmosis membrane and the membrane shell; characterized in that further comprising: a elastic component installed in the center tube, one end of which is fixed to the closed end of the center tube; the membrane pure water outlet is formed on the wall of the non-elastic component containing part of the center tube; the length and / or compression performance of the elastic component are determined according to the estimation of the water production during the inertial operation of the booster pump, so as to meet the conditions of reverse flushing after the inertial operation of the booster pump stops; an adapter composed of a coaxial first sleeve and a circular ring part, the circular ring part abuts against the concentrated water outlet end face of the reverse osmosis membrane, and the first sleeve is sleeved on the periphery of the center tube to form a concentrated water outlet channel between the first sleeve and the outer wall of the center tube; when producing water, pure water is collected from the membrane pure water outlet formed on the wall of the center tube and flows out through the pure water outlet at the end of the center tube; when the faucet is closed, the booster pump continues to operate until the set water pressure is reached, the elastic component is compressed and generates elastic force, so that the continuously produced pure water is stored in the center tube; after shutdown, the elastic force reversely drives the elastic component to move, and the pure water in the center tube is reversely pressed into the reverse osmosis membrane through the membrane pure water outlet, and the raw water and concentrated water in the membrane are discharged through the concentrated water outlet.

2. The reverse osmosis membrane cartridge of claim 1, wherein, The length of the elastic component is greater than or equal to half the length of the center tube.

3. The reverse osmosis membrane cartridge of claim 1, wherein, The elastic component comprises: a spring fixed to the closed end of the center tube; a piston connected to the end of the spring.

4. The reverse osmosis membrane cartridge of claim 1, wherein, The elastic component is a rubber capsule pre-filled with gas.

5. The reverse osmosis membrane cartridge of claim 1, wherein, The adapter further comprises: a second sleeve vertically sleeved on the circumferential surface of the reverse osmosis membrane.

6. The reverse osmosis membrane cartridge of claim 1, wherein, The reverse osmosis membrane filter cartridge further comprises: a membrane cover provided with a raw water hole, a concentrated water hole and a pure water hole; the raw water hole is in communication with the raw water cavity; the concentrated water hole is in communication with the concentrated water outlet channel; and the pure water hole is in communication with the pure water outlet.

7. The reverse osmosis membrane cartridge of claim 1, wherein, A first limiting structure is arranged on the wall of the center tube above the membrane pure water outlet, for limiting the maximum stroke of the elastic component.

8. The reverse osmosis membrane cartridge of claim 1, wherein, A second limiting structure is extended from the position inside the membrane shell opposite to the closed end of the center tube, and the closed end of the center tube is limited in the second limiting structure.

9. Water purification apparatus, characterized in that A reverse osmosis membrane filter cartridge according to any one of claims 1-8. 10.A control method of a water purification device, applied to the water purification device of claim 9, wherein a pressure switch is installed at the pure water outlet end of the water purification device; the method comprising: characterized in that controlling the booster pump to continue operating when the faucet of the water purification device is closed; receiving the detection signal of the pressure switch to determine the water pressure of the pure water outlet end; turning off the booster pump when the water pressure reaches the set water pressure. ​

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