A low pressure membrane method for seawater desalination device and method

Abstract

The application belongs to the technical field of seawater desalination equipment, and particularly relates to a low-pressure membrane method seawater desalination device and method, which comprises a water pump and a desalination device in conductive connection; a water pumping pipe is arranged on the input end of the water pump; the output end of the water pump is in conductive connection with the desalination device; the desalination device comprises a shell, a membrane cylinder and an anti-corrosion and moisture-retention mechanism; the moisture-retention plate, the water storage layer and the chemical agent adding device are arranged, the moisture-retention plate and the water storage layer are attached to the membrane cylinder by the change of the water pressure in the desalination cavity after the seawater desalination device is used, the addition of the chemical agent forms an antibacterial and anti-corrosion environment on the surface of the membrane cylinder, the water absorbed by the water storage layer can continuously moisten the membrane cylinder, the probability of the reverse osmosis membrane of the membrane cylinder drying and shrinking is reduced, the growth of microorganisms is inhibited, a suitable environment for the preservation of the membrane cylinder is created, and the service life of the membrane cylinder is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of seawater desalination equipment, in particular to a low-pressure membrane method seawater desalination device and method. BACKGROUND

[0002] In the marine environment, there are great difficulties in freshwater resource supply, and the supply points in the open sea area are scarce. Freshwater transportation is high in cost and time-consuming, and is easily affected by weather and sea conditions. Portable seawater desalination devices can directly produce fresh water on site at sea, significantly reducing the dependence on external supplies, so they can be used as a backup solution for freshwater supply.

[0003] Most portable seawater desalination devices use reverse osmosis membranes as the main separation element to separate the solvent and solute in the solution under pressure, thereby achieving rapid desalination of seawater. In actual application, seawater not only contains water resources, but also contains impurities such as algae and microorganisms. Therefore, during the continuous concentration and desalination of seawater, although most of the impurities entering the seawater desalination device are discharged with the concentrated water, some algae or microorganism impurities may adhere to the reverse osmosis membrane and proliferate and decay over time, causing damage to the reverse osmosis membrane and even failure of the seawater desalination device.

[0004] In order to reduce the problems caused by seawater residues in related technologies, a portable seawater desalination device is disclosed in application No. CN2024117979465. The device uses a blocking mechanism to guide the air and seawater in the water inlet pipe, so that the air in the water inlet pipe can be stored in the air storage cavity in advance, thereby utilizing the air in the water inlet pipe to clean the RO membrane. However, in actual application, it is found that only air impact and cleaning of the reverse osmosis membrane can remove some residual impurities and seawater, but some residues remain. In addition, complete removal of moisture from the space where the reverse osmosis membrane is stored can also cause the reverse osmosis membrane to gradually dry during storage. Therefore, the dry reverse osmosis membrane needs to be soaked and rinsed for a long time before it can stably separate seawater, which is inconvenient to use.

[0005] Therefore, the present application provides a low-pressure membrane method seawater desalination device and method to solve the above technical problems. SUMMARY

[0006] In order to make up for the shortcomings of the prior art and solve the above technical problems, the present application provides a low-pressure membrane method seawater desalination device and method.

[0007] The technical scheme adopted by the present application to solve its technical problems is: the low-pressure membrane seawater desalination device comprises a water pump and a desalination device connected in parallel;

[0008] The water pump is provided with a water suction pipe at the input end, and the output end of the water pump is connected in parallel with the desalination device;

[0009] The desalination device comprises a shell, a membrane cartridge and a corrosion and moisture preservation mechanism.

[0010] The shell is a hollow structure, and the membrane cartridge is detachably installed in the shell.

[0011] The shell is provided with a fresh water pipe and a concentrated water pipe at the bottom end.

[0012] The corrosion and moisture preservation mechanism is installed in the desalination cavity.

[0013] The shell is provided with a translation groove, which is uniformly arranged around the circumference of the membrane cartridge.

[0014] The moisture preservation plate is elastically and slidably installed in the translation groove by an elastic member.

[0015] The shell is provided with a medicator.

[0016] Preferably, the elastic member is a combination of an elastic film and a supporting spring.

[0017] Preferably, the medicator is composed of a medicine storage tank, a dosing tube and a communication pipe.

[0018] Preferably, the moisturizing plate is sleeved with a sealing sleeve ring, which is made of elastic rubber material and completely surrounds the outer periphery of the membrane cylinder in the initial state.

[0019] Preferably, the moisturizing plate is hinged by a connecting end and two arc-shaped plates, and the two arc-shaped plates are elastically connected by a tension spring, the elastic force of the tension spring is smaller than that of the supporting spring, and the arc-shaped plates are fixedly installed with scrapers on the sides away from each other.

[0020] Preferably, the shell is detachably fixedly installed with a backflushing tank, the bottom end of the backflushing tank is in conductive connection with the freshwater pipe, and the top end of the backflushing tank is installed with a water outlet pipe.

[0021] Preferably, the backflushing tank is composed of an expansion pipe, and the water outlet pipe is installed with a pressure conductive valve at the conductive position of the backflushing tank.

[0022] Preferably, the shell is installed with a sealing sleeve, which extends into the inner cavity of the membrane cylinder, and the sealing sleeve is composed of a plurality of vertical rods and closure plates.

[0023] The vertical rods are fixedly installed on the shell and extend into the interior of the membrane cylinder, the plurality of vertical rods are uniformly arranged along the circumferential direction of the membrane cylinder, the closure plates are fixedly installed on the vertical rods, the closure plates are composed of elastic metal sheets, and in the initial state, the closure plates are attached to the inner wall of the membrane cylinder and covered by the plurality of closure plates in cooperation with the vertical rods.

[0024] Preferably, the moisturizing plate and the closure plate are in one-to-one correspondence and are designed to be staggered.

[0025] A low-pressure membrane method for seawater desalination, the method comprising the following steps:

[0026] S1: Place the water suction pipe installed with a filter head in seawater, and simultaneously start the water pump, when the water pump is working, continuously pump seawater through the filter head and the water suction pipe into the water pump, and finally pump into the desalination cavity;

[0027] S2: As the seawater in the desalination cavity continues to be pumped in, the water pressure in the desalination cavity increases, under the action of the water pressure, the elastic member moves towards the interior of the translation groove, thereby causing the moisturizing plate to gradually shrink, and the membrane cylinder contacts the seawater in the desalination cavity;

[0028] S3: Under the separation action of the membrane cylinder, the seawater is separated into concentrated water and fresh water, and is discharged through the concentrated water pipe and the fresh water pipe respectively, wherein the water flow in the fresh water pipe is discharged into the backflushing tank, causing the water pressure in the backflushing tank to gradually increase;

[0029] S4: When the water pressure is greater than the opening pressure of the pressure conductive valve, the fresh water is discharged through the water outlet pipe, realizing continuous desalination of seawater.

[0030] The beneficial effects of the present application are as follows:

[0031] 1. The low-pressure membrane method seawater desalination device and method, by setting the moisturizing plate, water storage layer and medicament adding device, after the seawater desalination device is used, the moisturizing plate and the water storage layer are attached to the membrane cylinder by the change of the water pressure in the desalination cavity, and the bacteriostatic and anticorrosive environment is formed on the surface of the membrane cylinder by adding the medicament, the water absorbed in the water storage layer can continuously moisten the membrane cylinder, during the use interval of the seawater desalination device, the probability of the reverse osmosis membrane dry shrinkage of the membrane cylinder is reduced, the growth of microorganisms is inhibited, the suitable environment for the preservation of the membrane cylinder is created, and the service life of the membrane cylinder is prolonged.

[0032] 2. The low-pressure membrane method seawater desalination device and method, by closing the water pump, as the water pressure in the fresh water cavity gradually decreases, the backflushing tank gradually shrinks under the elastic action of itself, the fresh water remaining in the backflushing tank flows into the membrane cylinder, and the membrane cylinder is backflushed, at this time, the fresh water flows from the inside of the membrane cylinder to the desalination cavity, the scraping of the membrane cylinder surface by the scraper is matched, the efficiency of the impurities separating from the membrane cylinder is improved, and the difficulty of creating the suitable preservation environment for the membrane cylinder is further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0033] The present application will be further described below in conjunction with the drawings.

[0034] Figure 1 is a perspective view of the present application;

[0035] Figure 2 is an exploded view of the present application;

[0036] Figure 3 is an exploded view of the desalination device;

[0037] Figure 4 is a split view of the backflushing tank and the water outlet pipe;

[0038] Figure 5 is a process schematic diagram of the membrane cylinder sleeve setting rod and the closing plate;

[0039] Figure 6 is an assembly schematic diagram of the shell and the elastic piece;

[0040] Figure 7 is a split schematic diagram of the moisturizing plate and the sealing sleeve ring, the water storage layer and the scraper;

[0041] Figure 8 is a connection schematic diagram of the moisturizing plate and the quantitative pipe and the communication pipe;

[0042] Figure 9 is an internal schematic diagram of the shell in the initial state;

[0043] Figure 10 is a method flow chart of the present application;

[0044] In the figure: 1, water pump; 11, water suction pipe; 2, shell; 21, membrane cylinder; 22, desalination cavity; 23, fresh water pipe; 24, concentrated water pipe; 25, moisturizing plate; 26, water storage layer; 27, translation groove; 28, elastic membrane; 29, supporting spring; 3, medicine storage tank; 31, metering pipe; 32, communication pipe; 4, sealing ring; 41, tension spring; 42, scraper; 5, backflushing tank; 51, water outlet pipe; 52, pressure conduction valve; 53, vertical rod; 54, closing plate. DETAILED DESCRIPTION

[0045] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.

[0046] As shown in Figures 1 to 10 The low-pressure membrane method seawater desalination device of the present application comprises a water pump 1 and a desalination device connected in parallel. In the present application, the water pump 1 uses different power sources in different embodiments. For example, in an emergency or energy shortage environment, the water pump 1 uses a plunger type water pump driven by manpower. In a ship or a water-based work platform environment, the water pump 1 selects a centrifugal type water pump driven by electricity. Based on this, the low-pressure membrane method seawater desalination device produced by the present application can be divided into multiple models according to the type of the installed water pump 1, and is respectively applied to different working environments.

[0047] The water pump 1 is provided with a water suction pipe 11 at the input end. The water suction pipe 11 is provided with a filter head for filtering impurities at the end away from the water pump 1, which is used for filtering solid impurities in seawater. The output end of the water pump 1 is connected in parallel with the desalination device.

[0048] The desalination device comprises a shell 2, a membrane cylinder 21 and a corrosion and moisturizing mechanism.

[0049] The shell 2 is a hollow structure. The membrane cylinder 21 is detachably installed in the shell 2. The membrane cylinder 21 is a cylindrical structure composed of a reverse osmosis membrane and a support. The desalination cavity 22 is formed between the membrane cylinder 21 and the inner wall of the shell 2.

[0050] The shell 2 is provided with a fresh water pipe 23 and a concentrated water pipe 24 fixedly installed at the bottom end. The fresh water pipe 23 is connected in parallel with the inner cavity of the membrane cylinder 21. The concentrated water pipe 24 is connected in parallel with the desalination cavity 22.

[0051] The corrosion and moisturizing mechanism is installed in the desalination cavity 22. The corrosion and moisturizing mechanism is used for corrosion and moisturizing treatment of the membrane cylinder 21. The corrosion and moisturizing mechanism comprises:

[0052] The moisture plate 25 is elastically slidably installed in the translation groove 27 through an elastic member.

[0053] The water storage layer 26 is fixedly installed on one side of the moisture plate 25 facing the membrane cylinder 21, and is knitted by water-absorbing fiber material. The water-absorbing fiber material has capillary action and the diffusion effect of the medicament in water, so as to facilitate the diffusion of the medicament added to the water storage layer 26, and then change the surface environment of the membrane group by using the diffused medicament to prevent or inhibit the growth of microorganisms.

[0054] The medicament adding device is installed on the shell 2, penetrates the shell 2, and extends to the moisture plate 25. The opening of the medicament adding device is located in the water storage layer 26.

[0055] The elastic member is a combination of an elastic film 28 and a supporting spring 29. The supporting spring 29 is fixedly installed in the translation groove 27, and the elastic film 28 is fixedly installed at the junction of the translation groove 27 and the desalination cavity 22. The elastic film 28 separates the desalination cavity 22 and the translation groove 27. In the initial state, the elastic film 28 protrudes into the desalination cavity 22, and the moisture plate 25 blocks the opening of the concentrated water pipe 24.

[0056] In the research and development of the portable emergency seawater desalination device, due to the limitations of size and energy, the pre-filtering impurity removal precision of the portable emergency seawater desalination device is not high. Therefore, after the seawater desalination device is used, small plant tissues, microorganisms and other impurities are usually left on the surface of the membrane cylinder 21 composed of reverse osmosis membranes. These plant tissues, microorganisms and other impurities left on the surface of the membrane cylinder 21 cannot be completely removed by simple cleaning, and may cause corruption and reproduction over time, which may cause irreversible damage to the membrane cylinder 21. Therefore, the anti-corrosion and moisture-retention structure is arranged to maintain the membrane cylinder 21 and prolong the service life of the membrane cylinder 21.

[0057] Specifically, in the seawater desalination process, the bottom end of the water suction pipe 11 is placed in seawater, and as the water pump 1 continues to suck, the seawater is filtered by the filter head, impurities are removed, and then pumped into the desalination device by the water pump 1. At this time, the solid impurities contained in the seawater are greatly reduced, and the seawater after impurity removal enters the desalination cavity 22 in the desalination device. Under the action of continuous pumping, the water pressure in the desalination cavity 22 increases, and the water pressure uniformly acts on the membrane cylinder 21 and the elastic member. Because the elastic member extends into the desalination cavity 22 in the initial state, the volume of the desalination cavity 22 is small, and under the action of the continuously increasing water pressure, the elastic membrane 28 is deformed towards the translation groove 27, and the supporting spring 29 is compressed and shrunk. Because the moisturizing plate 25 is installed on the elastic member, when the elastic membrane 28 deforms towards the translation groove 27, the moisturizing plate 25 gradually moves away from the membrane cylinder 21 from the state of being attached to the surface of the membrane cylinder 21 in the initial state. In the process of moving the moisturizing plate 25, the opening of the concentrated water pipe 24 gradually communicates with the desalination cavity 22, so that the concentrated water can be discharged from the concentrated water pipe 24. When the moisturizing plate 25 is separated from the membrane cylinder 21, part of the fresh water enters the inner cavity of the membrane cylinder 21 and is discharged into the fresh water pipe 23 along the inner cavity of the membrane cylinder 21, thereby realizing continuous desalination of seawater. When the seawater desalination device stops being used, the water pump 1 stops, the supporting spring 29 gradually recovers from the compressed state, pushes the elastic membrane 28 to extrude into the desalination cavity 22 again, and finally the side of the moisturizing plate 25 installed with the water storage layer 26 is attached to the membrane cylinder 21 again. At the same time, the medicator is used to add an antiseptic agent (in this embodiment, the antiseptic agent is preferably sodium bisulfite) to the water storage layer 26. The agent diffuses in the water storage layer 26 and is attached to the membrane cylinder 21 through the water storage layer 26, thereby realizing moisturizing and antiseptic treatment of the surface of the membrane cylinder 21.

[0058] By setting the moisturizing plate 25, the water storage layer 26 and the medicator, when the seawater desalination device is used, the water pressure in the desalination cavity 22 changes, so that the moisturizing plate 25 and the water storage layer 26 are attached to the membrane cylinder 21. The addition of the agent forms a bacteriostatic and antiseptic environment on the surface of the membrane cylinder 21. At the same time, the water absorbed by the water storage layer 26 can continuously moisturize the membrane cylinder 21. In the interval between the use of the seawater desalination device, the probability of drying and shrinking of the reverse osmosis membrane constituting the membrane cylinder 21 can be reduced, the growth of microorganisms can be inhibited, and a suitable environment for the preservation of the membrane cylinder 21 can be created, thereby prolonging the service life of the membrane cylinder 21.

[0059] As a preferred embodiment of the present application, the medicine feeder is composed of a medicine storage tank 3, a dosing tube 31 and a communication tube 32, the medicine storage tank 3 is detachably mounted on the shell 2, the communication tube 32 is fixedly mounted at one end of the outlet of the medicine storage tank 3 and extends to the water storage layer 26 at the other end, the dosing tube 31 is mounted in the middle of the communication tube 32, the dosing tube 31 is composed of an extension tube, the dosing tube 31 is connected in series in the middle of the communication tube 32 through a one-way valve, the dosing tube 31 is mounted in the translation groove 27, and the two ends of the dosing tube 31 are fixedly connected with the shell 2 and the elastic film 28 respectively, and in the present application, the communication tube 32 is the general term of the pipeline connected from the medicine storage tank 3 to the dosing tube 31 and extending from the dosing tube 31 to the water storage layer 28.

[0060] In order to facilitate the addition of the medicine and realize the quantitative addition of the medicine, in the present application, when the water pressure in the desalination cavity 22 gradually increases, the elastic member is deformed gradually in the direction of the translation groove 27, thereby extruding the dosing tube 31, in the present embodiment, the dosing tube 31 is composed of a tube body and a piston with a rod, when the dosing tube 31 is extruded, the piston with a rod moves to the inside of the tube body, at this time, a negative pressure is formed in the rod cavity of the tube body, under the action of the negative pressure, the medicine in the medicine storage tank 3 is extracted to the rod cavity of the tube body through the communication tube 32, when the water pressure gradually decreases, the dosing tube 31 is reset in the process of resetting of the elastic member, at this time, the piston with a rod moves gradually away from the outside of the tube body, the volume of the rod cavity of the tube body is reduced, thereby causing the medicine to be discharged to the water storage layer 26 through the one-way valve and the communication tube 32 under the action of the pressure, and gradually diffusing in the water storage layer 26 by the capillary action and the penetration action in the water storage layer 26, so as to create a suitable environment for the surface of the membrane cylinder 21 when the water storage layer 26 is attached to the surface of the membrane cylinder 21.

[0061] It should be known that in other embodiments of the present application, the medicine feeder can also be selected in other structures in order to add the medicine to the water storage layer 26 after the seawater desalination device is stopped, meanwhile, the communication tube 32 can also extend and arrange in the water storage layer 26 and cooperate with the multi-opening delivery channel in order to enhance the uniformity of the diffusion of the medicine in the water storage layer 26.

[0062] As a preferred embodiment of the present application, the sealing sleeve ring 4 is mounted on the moisturizing plate 25, the sealing sleeve ring 4 is made of elastic rubber material, and the moisturizing plate 25 completely surrounds the outer circumferential surface of the membrane cylinder 21 in the initial state by cooperating with the sealing sleeve ring 4.

[0063] The moisturizing plate 25 is connected by a connecting end and two arc-shaped plates, wherein the connecting end is fixedly installed on the elastic film 28, and the two arc-shaped plates are hingedly connected to the connecting end, and the two arc-shaped plates are elastically connected by a tension spring 41 located inside the water storage layer 26, when the moisturizing plate 25 is away from the membrane cylinder 21, the two arc-shaped plates are close to each other under the action of the tension spring 41, so that the water storage layer 26 fixed on the arc-shaped plate is deformed by extrusion, and the elastic force of the tension spring 41 is smaller than the elastic force of the supporting spring 29, and the arc-shaped plates are fixedly installed with a scraper 42 on the side away from each other.

[0064] In order to further reduce the probability of corruption and microbial proliferation on the surface of the membrane cylinder 21, and to create a suitable environment for the preservation of the membrane cylinder 21, in the present application, a sealing sleeve 4 is sleeved on the moisturizing plate 25, and the sealing sleeve 4 is evenly laid along the edge of the moisturizing plate 25, when the plurality of moisturizing plates 25 are attached to the surface of the membrane cylinder 21, under the mutual extrusion and adhesion of the sealing sleeve 4, the plurality of moisturizing plates 25 completely surround the outer periphery of the membrane cylinder 21, on the one hand, the completely surrounding form can enhance the adhesion effect of the membrane cylinder 21 and the water storage layer 26, so that the effect of the medicament on the membrane cylinder 21 is more uniform, on the other hand, the completely surrounding form can also effectively reduce the diffusion efficiency of water vapor in the water storage layer 26 to the desalination cavity 22, and delay the rate of water loss in the water storage layer 26, and when the seawater desalination device is started and the water pressure in the desalination cavity 22 gradually increases, the elastic member is retracted into the translation groove 27, at this time, the moisturizing plate 25 gradually moves away from the membrane cylinder 21, the two arc-shaped plates constituting the moisturizing plate 25 are gradually deflected and closed under the pulling of the tension spring 41, and the scraper 42 installed at the end of the arc-shaped plate scrapes the surface of the membrane cylinder 21, thereby achieving the cleaning of the surface of the membrane cylinder 21, and when the seawater desalination device is turned off and the water pressure in the desalination cavity 22 gradually decreases, the elastic member deforms towards the desalination cavity 22, at this time, the moisturizing plate 25 gradually approaches the membrane cylinder 21, the two arc-shaped plates constituting the moisturizing plate 25 gradually open under the obstruction of the membrane cylinder 21, and in the process of opening, the scraper 42 also scrapes the membrane cylinder 21 to remove impurities on the surface of the membrane cylinder 21, therefore, under the action of scraping and cleaning, the adhesion of impurities on the surface of the membrane cylinder 21 can be effectively reduced, and the difficulty of creating a suitable preservation environment on the surface of the membrane cylinder 21 is reduced by adding medicaments.

[0065] As a preferred embodiment of the present application, the shell 2 is detachably fixedly installed with a backflush tank 5, the bottom end of the backflush tank 5 is in communication with the fresh water pipe 23, and the top end of the backflush tank 5 is installed with a water outlet pipe 51.

[0066] The back flushing tank 5 is made of an expandable tube, the water outlet pipe 51 is provided with a pressure conducting valve 52 at the position where the water outlet pipe 51 is communicated with the back flushing tank 5, in the present application, the expandable tube is made of an elastic deformable material, under the action of water pressure, the volume of the back flushing tank 5 is increased until the pressure in the back flushing tank 5 reaches the opening pressure of the pressure conducting valve 52, at this time, fresh water is discharged from the water outlet pipe 51.

[0067] In order to further enhance the cleaning effect of the membrane cylinder 21 and reduce the difficulty of creating a suitable environment for the membrane cylinder 21, the shell 2 is provided with a back flushing tank 5, when the water pressure in the desalination cavity 22 increases, fresh water enters the inner cavity of the membrane cylinder 21 and is discharged through the fresh water pipe 23, under the action of water pressure, the fresh water enters the back flushing tank 5 through the fresh water pipe 23 and the volume of the back flushing tank 5 is expanded until the pressure in the back flushing tank 5 reaches the opening pressure of the pressure conducting valve 52, at this time, fresh water is discharged from the water outlet pipe 51, and when the water pump 1 is turned off, as the water pressure in the fresh water cavity gradually decreases, the back flushing tank 5 gradually shrinks under the action of its own elasticity, forcing the fresh water remaining in the back flushing tank 5 to flow into the membrane cylinder 21 and form a back flushing for the membrane cylinder 21, at this time, the fresh water flows from the inner side of the membrane cylinder 21 to the desalination cavity 22, cooperating with the scraping of the scraping plate 42 on the surface of the membrane cylinder 21, the efficiency of the impurities separating from the membrane cylinder 21 is improved, and the difficulty of creating a suitable storage environment for the membrane cylinder 21 is further reduced.

[0068] As a preferred embodiment of the present application, a sealing sleeve is mounted on the shell 2, the sealing sleeve extends into the inner cavity of the membrane cylinder 21, the sealing sleeve is composed of a plurality of vertical rods 53 and a closing plate 54;

[0069] The vertical rod 53 is fixedly installed on the shell 2, the vertical rod 53 extends into the inner part of the membrane cylinder 21, a plurality of vertical rods 53 are uniformly arranged along the circumferential direction of the membrane cylinder 21, the closing plate 54 is fixedly installed on the vertical rod 53, the closing plate 54 is made of an elastic metal sheet, in the initial state, the closing plate 54 is attached to the inner wall of the membrane cylinder 21, and a plurality of closing plates 54 cover the inner wall of the membrane cylinder 21 in cooperation with the vertical rods 53.

[0070] The moisturizing plate 25 corresponds to the closing plate 54 one by one, and is designed in a staggered manner.

[0071] In actual assembly, the pull rod and the closing plate 54 are first installed in the middle part of the inner cavity of the shell 2, then the membrane cylinder 21 is sleeved on the outside of the plurality of vertical rods 53 and the closing plate 54 through the bottom opening, and finally falls to the bottom of the inner cavity of the shell 2, and is finally detachably fixed and connected with the bottom of the inner cavity of the shell 2. In this embodiment, the membrane cylinder 21 and the bottom of the inner cavity of the shell 2 are connected in a threaded manner, that is, during the installation process, the membrane cylinder 21 is first covered by the vertical rods 53 and the closing plate 54 through the bottom opening, and then the membrane cylinder 21 is screwed, so that the membrane cylinder 21 is fixed with the shell 2 by screwing. When the water pressure in the fresh water cavity increases, the fresh water flows to the fresh water pipe 23 through the membrane cylinder 21, at this time the fresh water impacts the closing plate 54, causing the closing plate 54 to deform towards the axis of the membrane cylinder 21, and when the water pressure in the desalination cavity 22 gradually decreases, the fresh water in the backflushing tank 5 flows back through the fresh water pipe 23. Under the impact of the fresh water and the elasticity of the closing plate 54 itself, the closing plate 54 is attached to the inner wall of the membrane cylinder 21, and the fresh water flows to the membrane cylinder 21 and the water storage layer 26 through the gap of the closing plate 54. Therefore, before the membrane cylinder 21 is completely blocked by the moisturizing plate 25 cooperating with the sealing sleeve ring 4, the fresh water flows into the desalination cavity 22 through the gap of the moisturizing plate 25 after backflushing the membrane cylinder 21, at this time the concentrated water has not been completely discharged, the setting of the closing plate 54 makes the fresh water backflushing rate slower and the backflushing time longer, so as to completely discharge the concentrated water, and after the moisturizing plate 25 cooperates with the sealing sleeve ring 4 to completely block the membrane cylinder 21, at this time the backflushing tank 5 returns to its original state, and the water in the membrane cylinder 21 provides fresh water support for the moisturizing of the membrane cylinder 21 through the gap of the closing plate 54.

[0072] In the present application, when the water pump 1 is started, the water pressure in the fresh water cavity continues to increase, and after the elastic member deforms, the concentrated water pipe 24 opening is opened. Because the drainage efficiency of the concentrated water pipe 24 is less than the pumping efficiency of the water pump 1, the water pressure in the desalination cavity 22 continues to increase, and the fresh water flows through the membrane cylinder 21 and the fresh water pipe 23 under the action of pressure, enters the backflushing tank 5, and causes the backflushing tank 5 to expand, and finally is discharged through the water outlet pipe 51. When the water pump 1 is turned off, the water pressure in the fresh water cavity decreases, at this time the backflushing tank 5 first contracts, part of the fresh water flows back to the fresh water cavity, at this time the concentrated water continues to be discharged, and as the backflushing tank 5 gradually returns to its original state, the elastic member and the moisturizing plate 25 reset to block the membrane cylinder 21, and in this process, the medicament is added to create a suitable environment for the membrane cylinder 21.

[0073] A low-pressure membrane method for seawater desalination, the method comprising the following steps:

[0074] S1: Place the water suction pipe 11 provided with a filter head in seawater, and start the water pump 1 at the same time. When the water pump 1 is working, it continuously sucks seawater through the filter head and the water suction pipe 11 into the water pump 1, and finally pumps it into the desalination cavity 22;

[0075] S2: with the continuous pumping of seawater in the desalination cavity 22, the water pressure in the desalination cavity 22 increases, under the action of water pressure, the elastic member moves to the inside of the translation groove 27, and then the moisturizing plate 25 gradually shrinks, the membrane cylinder 21 is in contact with the seawater in the desalination cavity 22;

[0076] S3: under the separation action of the membrane cylinder 21, the seawater is divided into concentrated water and fresh water, and is discharged by the concentrated water pipe 24 and the fresh water pipe 23 respectively, wherein the water flow in the fresh water pipe 23 is discharged into the backflush tank 5, so that the water pressure in the backflush tank 5 gradually increases;

[0077] S4: when the water pressure is greater than the opening pressure of the pressure conduction valve 52, the fresh water is discharged through the water outlet pipe 51, and the continuous desalination operation of seawater is realized.

[0078] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A low-pressure membrane seawater desalination device, comprising a water pump (1) and a desalinator connected in series; The water pump (1) is provided with a water suction pipe (11) at the input end, and the output end of the water pump (1) is connected in series with the desalinator; characterized in that The desalinator comprises a shell (2), a membrane cylinder (21) and a corrosion and moisture preservation mechanism; The shell (2) is a hollow structure, and the membrane cylinder (21) is detachably installed in the shell (2). The membrane cylinder (21) is a cylindrical structure composed of a reverse osmosis membrane and a support, and a desalination cavity (22) is formed between the membrane cylinder (21) and the inner wall of the shell (2); The shell (2) is provided with a fresh water pipe (23) and a concentrated water pipe (24) fixedly installed at the bottom end. The fresh water pipe (23) is connected in series with the inner cavity of the membrane cylinder (21), and the concentrated water pipe (24) is connected in series with the desalination cavity (22); The corrosion and moisture preservation mechanism is installed in the desalination cavity (22) and is used for corrosion and moisture preservation treatment of the membrane cylinder (21). The corrosion and moisture preservation mechanism comprises: A moisture preservation plate (25) is provided in the shell (2) and is arranged uniformly around the circumference of the membrane cylinder (21). The moisture preservation plate (25) is elastically and slidably installed in the translation groove (27) by an elastic member. A water storage layer (26) is fixedly installed on one side of the moisture preservation plate (25) facing the membrane cylinder (21). The water storage layer (26) is woven from water-absorbing fiber material. A medicine feeder is installed on the shell (2) and penetrates the shell (2) and extends to the moisture preservation plate (25). The opening of the medicine feeder is located inside the water storage layer (26). The elastic member is a combination of an elastic film (28) and a supporting spring (29). The supporting spring (29) is fixedly installed in the translation groove (27), and the elastic film (28) is fixedly installed at the joint of the desalination cavity (22) and the translation groove (27). In the initial state, the elastic film (28) protrudes into the desalination cavity (22), and the moisture preservation plate (25) blocks the opening of the concentrated water pipe (24). The medicine feeder is composed of a medicine storage tank (3), a dosing tube (31) and a communication pipe (32). The medicine storage tank (3) is detachably installed on the shell (2). One end of the communication pipe (32) is fixedly installed at the outlet of the medicine storage tank (3), and the other end extends into the water storage layer (26). The dosing tube (31) is installed in the middle of the communication pipe (32). The dosing tube (31) is composed of an extension tube. The dosing tube (31) is connected in series with the middle of the communication pipe (32) through a one-way valve. The dosing tube (31) is installed in the translation groove (27), and the two ends of the dosing tube (31) are fixedly connected with the shell (2) and the elastic film (28). The moisturizing plate (25) is connected by a connecting end and two arc-shaped plates, wherein the connecting end is fixedly installed on the elastic film (28), and the two arc-shaped plates are hingedly connected to the connecting end; the two arc-shaped plates are elastically connected by a tension spring (41) located inside the water storage layer (26), and the elastic force of the tension spring (41) is smaller than that of the supporting spring (29).

2. A low pressure membrane sea water desalination unit as claimed in claim 1, wherein: A sealing sleeve ring (4) is sleeved and installed on the moisturizing plate (25), and the sealing sleeve ring (4) is made of elastic rubber material; in the initial state, the moisturizing plate (25) and the sealing sleeve ring (4) completely surround the outer circumferential surface of the membrane cylinder (21).

3. A low pressure membrane sea water desalination unit as claimed in claim 2, wherein: The arc-shaped plates are fixedly installed with scrapers (42) on the sides away from each other.

4. A low pressure membrane sea water desalination unit as claimed in claim 3, wherein: The shell (2) is detachably fixedly installed with a backflushing tank (5) at the outside, the bottom end of the backflushing tank (5) is in conductive connection with the fresh water pipe (23), and the top end of the backflushing tank (5) is installed with a water outlet pipe (51).

5. A low pressure membrane sea water desalination unit as claimed in claim 4, wherein: The backflushing tank (5) is composed of an expansion pipe, and the water outlet pipe (51) is installed with a pressure conductive valve (52) at the conductive position of the backflushing tank (5).

6. A low pressure membrane sea water desalination unit as claimed in claim 5, wherein: The shell (2) is installed with a sealing sleeve, which extends into the inner cavity of the membrane cylinder (21), and the sealing sleeve is composed of a plurality of vertical rods (53) and a closing plate (54). The vertical rods (53) are fixedly installed on the shell (2) and extend into the inner part of the membrane cylinder (21), and the plurality of vertical rods (53) are uniformly arranged along the circumferential direction of the membrane cylinder (21); the closing plate (54) is fixedly installed on the vertical rod (53) and is composed of an elastic metal sheet; in the initial state, the closing plate (54) is attached to the inner wall of the membrane cylinder (21), and the plurality of closing plates (54) cover the inner wall of the membrane cylinder (21) in cooperation with the vertical rods (53).

7. A low pressure membrane sea water desalination unit as claimed in claim 6, wherein: The moisturizing plate (25) corresponds to the closing plate (54) one by one and is designed in a staggered manner.

8. A low pressure membrane method of seawater desalination, characterized in that: The method is suitable for the low-pressure membrane seawater desalination device of claim 7, and comprises the following steps: S1: placing the water suction pipe (11) provided with the filter head in seawater and simultaneously starting the water pump (1); when the water pump (1) is working, seawater is continuously sucked into the water pump (1) through the filter head and the water suction pipe (11) and is finally pumped into the desalination cavity (22); S2: as the seawater in the desalination cavity (22) is continuously pumped in, the water pressure in the desalination cavity (22) increases, and under the action of the water pressure, the elastic member moves into the translation groove (27), so that the moisturizing plate (25) gradually shrinks, and the membrane cylinder (21) is in contact with seawater in the desalination cavity (22); S3: under the separation action of the membrane cylinder (21), seawater is separated into concentrated water and fresh water, which are discharged through the concentrated water pipe (24) and the fresh water pipe (23) respectively; the water flow in the fresh water pipe (23) is discharged into the backflushing tank (5), so that the water pressure in the backflushing tank (5) gradually increases; S4: when the water pressure is greater than the opening pressure of the pressure conductive valve (52), fresh water is discharged through the water outlet pipe (51), so that the seawater desalination operation is continuously performed.

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