CN117361777A - Be applied to low pressure high-efficient nanofiltration device in ultrapure water preparation - Google Patents

Abstract

The invention provides a low-pressure high-efficiency nanofiltration device applied to ultrapure water preparation, and relates to the technical field of ultrapure water preparation. The low-pressure high-efficiency nanofiltration device comprises a base, a first filtration frame, a second filtration frame and a mounting ring, wherein the middle part of the upper surface of the base is fixedly connected with three support frames respectively, the front end of the upper surface of the base is fixedly connected with a first mounting frame, and the rear end of the upper surface of the base is fixedly connected with a second mounting frame. The invention provides a low-pressure high-efficiency nanofiltration device applied to ultrapure water preparation, which greatly increases the filtration area in unit time by carrying out shunt filtration on water to be filtered, improves the filtration efficiency, simultaneously evenly distributes the load of each filter screen by the shunt filtration, avoids the premature blockage of a certain filter screen due to overlarge load, greatly prolongs the service life of the filter screen and simultaneously achieves the aim of reducing the running cost.

Description

A low-pressure and high-efficiency nanofiltration device used in ultrapure water preparation

Technical field

The invention relates to the technical field of ultrapure water preparation, specifically a low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water.

Background technique

Ultrapure water is highly purified water that has been rigorously treated and purified and contains virtually no appreciable impurities and ions. The preparation of ultrapure water mainly uses a series of physical, chemical and biological treatment technologies to remove dissolved substances, ions, microorganisms and suspended particles in the water. Ultrapure water preparation is a method used to remove dissolved impurities and ions in the water. In the process of high-purity water treatment, low-pressure and high-efficiency nanofiltration devices are mostly needed in the process of preparing ultrapure water. The low-pressure and high-efficiency nanofiltration device is a membrane separation technology that uses nanofiltration membranes to filter and separate water to remove contaminants in the water. Impurities such as suspended solids, colloidal particles, bacteria and most dissolved ions.

In the process of ultrapure water preparation, multi-stage filtration is usually used, in which low-pressure and high-efficiency nanofiltration devices are often used for the final precision filtration. Its core is a nanofiltration membrane, which has a smaller pore size and can effectively intercept most microorganisms, dissolved organic matter and ions. This ensures that the quality of ultrapure water reaches the required high purity requirements. In addition, the advantages of low-pressure high-efficiency nanofiltration devices include low energy consumption, high filtration efficiency and smaller equipment footprint.

However, most of the traditional low-pressure and high-efficiency nanofiltration devices are not convenient for diverting filtration of the sewage to be treated, thus reducing the filtering area per unit time and reducing the filtration efficiency. At the same time, it is difficult to evenly distribute the load of each filter, which can easily lead to A certain filter is clogged prematurely due to excessive load, which reduces the service life of the filter. At the same time, most traditional low-pressure and high-efficiency nanofiltration devices are inconvenient for staff to disassemble multiple filters. If one of them needs to be maintained or replaced, A filter is inconvenient to handle alone, which can easily affect the normal operation of the entire filtration system and increase downtime. For this reason, technical improvements are urgently needed.

Contents of the invention

(1) Technical problems solved

In view of the shortcomings of the existing technology, the present invention provides a low-pressure high-efficiency nanofiltration device used in the preparation of ultrapure water, which solves the problems of low filtration efficiency and low filtration area of the filter screen per unit time of the traditional low-pressure high-efficiency nanofiltration device. , which solves the problem that traditional low-pressure and high-efficiency nanofiltration devices are inconvenient for staff to disassemble a certain filter, which in turn causes inconvenience to staff in replacing and cleaning the filter.

(2) Technical solutions

In order to achieve the above objects, the present invention is realized through the following technical solutions: a low-pressure and high-efficiency nanofiltration device used in ultrapure water preparation, including a base, a first filter frame, a second filter frame and a mounting ring. Three supporting frames are fixedly connected to the middle part of the surface. The front end of the upper surface of the base is fixedly connected to a first mounting frame. The rear end of the upper surface of the base is fixedly connected to a second mounting frame. The outer wall of the front end of the second mounting frame A positioning circular groove is provided in the middle, and a filter outer barrel is provided in the middle of the first mounting frame and the second mounting frame;

The inner wall of the filter barrel is provided with a plurality of placement slots, and the side walls of the filter barrel are provided with a plurality of connecting pipes. The connecting pipes extend to the inside of the placement slots. The body of the connecting pipe A plurality of water spray heads are fixedly connected to each other, a plurality of limiting covers are fixedly connected to the inner wall of the filter outer barrel, a plurality of limiting blocks are fixedly connected to the outer wall of the first filter frame, and the limiting blocks are fixedly connected to Both are snap-fitted with the limit cover, the side walls of the first filter frame are fixedly connected with multiple coarse filter layers, and the side walls of the second filter frame are fixedly connected with multiple activated carbon filter layers;

The inner wall of the rear end of the filter outer barrel is fixedly connected with a first support ring, and the outer wall of the front end of the first support ring is fixedly connected with a plurality of support rods. One end of the support rods close to the center of the filter outer bucket is provided with a third support ring. A sliding groove, the outer wall of the rear end of the mounting ring is fixedly connected with a plurality of mounting sleeves, and a second sliding groove is provided at one end of the mounting sleeves close to the center of the filter outer barrel. The mounting sleeves are all set on the support rods. The outer wall of the installation sleeve is fixedly connected with a medium-sized filter layer, the inner wall of the rear end of the filter outer barrel is fixedly connected with a second support ring, and the interior of the second support ring is snap-fitted with a third filter frame. A plurality of sliding plates are fixedly connected to the outer wall of the third filter frame, and a plurality of third sliding grooves are provided on the upper surface of the mounting ring. The sliding plates are located between the first sliding groove, the second sliding groove and the second sliding groove. The interior of the third sliding groove is slidingly connected. The side walls of the third filter frame are fixedly connected with multiple precision filter layers. The inner wall of the third filter frame is fixedly connected with a nanofiltration layer. The inner wall of the nanofiltration layer is fixedly connected. The fixed connection has an ion exchange layer;

Through the above technical solution, the water to be filtered is diverted and filtered, which greatly increases the filtering area per unit time and improves the filtration efficiency. At the same time, the diverted filtration can evenly distribute the load of each filter, avoiding the need for a certain filter. Premature clogging due to excessive load greatly extends the service life of the filter and also achieves the purpose of reducing operating costs.

Preferably, a positioning cover is fixedly connected to the center of the inner wall of the rear end of the filter barrel. The outer wall of the positioning cover is provided with positioning semi-arc grooves. The inner wall of the rear end of the third filter frame is fixedly connected to a plurality of positioning covers. column, and the positioning columns are snap-fitted with the positioning half-arc groove.

Through the above technical solution and snap fit, the third filter frame can be more stable and less likely to shake when installed.

Preferably, the upper end of the support frame is provided with a support arc-shaped groove, and the bottom surface of the support arc-shaped groove is rotatably connected with a plurality of balls, and the balls are all slidingly connected with the lower surface of the filter outer barrel.

Through the above technical solution, the installation of the filter barrel can be made more convenient and stable through the use of balls.

Preferably, a water outlet seat is fixedly connected to the middle part of the outer wall of the rear end of the filter outer barrel. The rear end of the filter outer barrel is fixedly connected to the second mounting frame through bolts. The rear end of the water outlet seat penetrates the second mounting frame and is Extending to the outside of the second mounting frame, the front end of the filter barrel is fixedly connected to the first mounting frame through bolts.

Through the above technical solution, the filter outer barrel can be quickly fixed to the first mounting bracket and the second mounting bracket through bolted connection.

Preferably, the outer wall of the second filter frame is provided with a plurality of long limit slots, and the outer wall of the first filter frame is fixedly connected with a plurality of long limit rods, and the long limit rods are all in position. Long slotted internal sliding connection.

Preferably, the outer wall of the second support ring is fixedly connected to the inner wall of the first support ring.

Preferably, the outer wall of the front end of the filter barrel is fixedly connected with a sealing cover through bolts, the sealing cover, the outer wall of the front end of the sealing cover is fixedly connected with a water inlet seat, and a water collection chamber is provided inside the sealing cover. A shunt ring is fixedly connected to the edge of the water collection chamber, and a plurality of shunt holes are provided on the side walls of the shunt ring.

Preferably, a plurality of water injection heads are provided at the edge of the sealing cover, and the rear ends of the water injection heads are fixedly connected with water injection nozzles.

(3) Beneficial effects

The invention provides a low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water. Have the following

Beneficial effects:

1. The present invention provides a low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water. Compared with the existing low-pressure and high-efficiency nanofiltration device, the low-pressure and high-efficiency nanofiltration device greatly increases the filtering efficiency by dividing the water to be filtered. The filtration area per unit time improves the filtration efficiency. At the same time, the split filtration can evenly distribute the load of each filter to avoid premature blockage of a certain filter due to excessive load, which greatly extends the service life of the filter. At the same time, the purpose of reducing operating costs is also achieved.

2. The present invention provides a low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water. Compared with the existing low-pressure and high-efficiency nanofiltration device, the low-pressure and high-efficiency nanofiltration device can separate multiple filters. If maintenance is required, Or replace one of the filters, which can be processed separately without affecting the normal operation of the entire filtration system. This can improve the convenience of maintenance and replacement, reduce downtime, and also facilitate the disassembly and cleaning of the staff. Convenience for practical use by staff.

3. The present invention provides a low-pressure high-efficiency nanofiltration device used in the preparation of ultrapure water. Compared with the existing low-pressure high-efficiency nanofiltration device, the low-pressure high-efficiency nanofiltration device has a compact and reasonable overall structure, high filtration efficiency, and good filtration effect. The operating cost is low and it is convenient for staff to disassemble and clean a single filter rack.

Description of the drawings

Figure 1 is a schematic diagram of the main structure of the present invention;

Figure 2 is a schematic structural diagram of the support frame, the first mounting frame and the second mounting frame of the present invention;

Figure 3 is a schematic structural diagram of the filter outer barrel of the present invention;

Figure 4 is a schematic structural diagram of the first filter frame of the present invention;

Figure 5 is a schematic structural diagram of the second filter frame of the present invention;

Figure 6 is a schematic structural diagram of the first support ring and support rod of the present invention;

Figure 7 is a schematic structural diagram of the support rod, first sliding groove, mounting ring and mounting sleeve of the present invention;

Figure 8 is a schematic structural diagram of the second support ring and the third filter frame of the present invention;

Figure 9 is a schematic structural diagram of the third filter frame, precision filter layer, sliding plate, nanofiltration layer and ion exchange layer of the present invention;

Figure 10 is a schematic structural diagram of the sliding plate, mounting ring and mounting sleeve of the present invention;

Figure 11 is a partial structural schematic diagram of the support rod, installation sleeve and third filter frame of the present invention;

Figure 12 is a schematic structural diagram of the filter outer barrel, positioning cover and positioning half arc groove of the present invention;

Figure 13 is a schematic structural diagram of the sealing cover, water inlet seat and water injection nozzle of the present invention;

Figure 14 is a schematic structural diagram of the water collection chamber, diverter ring, diverter hole and water injection head of the present invention;

Figure 15 is a schematic structural diagram of one side of the filter barrel of the present invention.

Among them, 1. Base; 2. Support frame; 3. Support arc groove; 4. Ball; 5. First mounting frame; 6. Second mounting frame; 7. Positioning circular groove; 8. Water outlet seat; 9. Filter outer barrel; 10. Placement slot; 11. Connecting pipe; 12. Water spray head; 13. Limiting cover; 14. First filter frame; 15. Limiting block; 16. Coarse filter layer; 17. Limiting length Rod; 18. Second filter frame; 19. Long limit slot; 20. Activated carbon filter layer; 21. First support ring; 22. Support rod; 23. First sliding groove; 24. Installation ring; 25. Installation sleeve ; 26. Second sliding groove; 27. Medium filter layer; 28. Second support ring; 29. Third filter frame; 30. Precision filter layer; 31. Sliding plate; 32. Nanofiltration layer; 33. Ion exchange layer ; 34. Positioning column; 35. Third sliding groove; 36. Positioning cover; 37. Positioning half-arc groove; 38. Sealing cover; 39. Water inlet seat; 40. Water collection chamber; 41. Diverter ring; 42. Diverter hole; 43, water injection head; 44, water injection nozzle.

Implementation

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

As shown in Figures 1-15, the embodiment of the present invention provides a low-pressure and high-efficiency nanofiltration device used in ultrapure water preparation, including a base 1, a first filter frame 14, a second filter frame 18 and a mounting ring 24. The base There are three supporting brackets 2 fixedly connected to the middle part of the upper surface of 1. The front end of the upper surface of base 1 is fixedly connected to a first mounting bracket 5. The rear end of the upper surface of base 1 is fixedly connected to a second mounting bracket 6. The second mounting bracket 6 A positioning circular groove 7 is provided in the middle of the outer wall of the front end. A filter outer barrel 9 is provided in the middle of the first mounting bracket 5 and the second mounting bracket 6. A supporting arc-shaped groove 3 is provided at the upper end of the supporting frame 2 to support the arc shape. The bottom surface of the groove 3 is rotatably connected with a plurality of balls 4, and the balls 4 are all slidingly connected to the lower surface of the filter barrel 9. The balls 4 can make the installation of the filter barrel 9 more convenient and stable;

The inner wall of the filter outer barrel 9 is provided with a plurality of placement slots 10, and the side walls of the filter outer barrel 9 are provided with a plurality of connecting pipes 11. The connecting pipes 11 all extend to the inside of the placing slots 10, and the bodies of the connecting pipes 11 are evenly spaced. A plurality of water spray heads 12 are fixedly connected, a plurality of limit covers 13 are fixedly connected to the inner wall of the filter outer barrel 9, a plurality of limit blocks 15 are fixedly connected to the outer wall of the first filter frame 14, and the limit blocks 15 are fixedly connected to each other. Snap-fitted with the limiting cover 13, the side walls of the first filter frame 14 are fixedly connected with a plurality of coarse filter layers 16, and the side walls of the second filter frame 18 are fixedly connected with a plurality of activated carbon filter layers 20;

The inner wall of the rear end of the filter outer barrel 9 is fixedly connected with a first support ring 21. The outer wall of the front end of the first support ring 21 is fixedly connected with a plurality of support rods 22. One end of the support rods 22 close to the center of the filter outer bucket 9 is provided with a first support ring 21. A sliding groove 23 and a plurality of installation sleeves 25 are fixedly connected to the outer wall of the rear end of the installation ring 24. The installation sleeves 25 are provided with a second sliding groove 26 at one end close to the center of the filter outer barrel 9. The installation sleeves 25 are all set on the support. The outer wall of the rod 22 and the outer wall of the installation sleeve 25 are fixedly connected with a medium filter layer 27. The inner wall of the rear end of the filter outer barrel 9 is fixedly connected with a second support ring 28. The interior of the second support ring 28 is snap-fitted with a third filter frame. 29. A plurality of sliding plates 31 are fixedly connected to the outer walls of the third filter frame 29, and a plurality of third sliding grooves 35 are provided on the upper surface of the mounting ring 24. The sliding plates 31 are located between the first sliding groove 23 and the second sliding groove 35. The groove 26 and the third sliding groove 35 are slidingly connected internally. The side walls of the third filter frame 29 are fixedly connected with a plurality of precision filter layers 30. The inner wall of the third filter frame 29 is fixedly connected with a nanofiltration layer 32. The nanofiltration layer The inner wall of 32 is fixedly connected with an ion exchange layer 33, and the center of the inner wall of the rear end of the filter outer barrel 9 is fixedly connected with a positioning cover 36. The outer walls of the positioning cover 36 are provided with positioning semi-arc grooves 37. They are all fixedly connected with a plurality of positioning posts 34, and the positioning posts 34 are snap-fitted with the positioning half-arc grooves 37. Through snap-fitting, the third filter frame 29 can be more stable and less likely to shake when the installation is completed;

By diverting the water to be filtered, the filtering area per unit time is greatly increased and the filtration efficiency is improved. At the same time, the diverted filtration can evenly distribute the load of each filter to prevent a certain filter from being damaged due to excessive load. Premature clogging greatly extends the service life of the filter and also achieves the purpose of reducing operating costs.

The middle part of the outer wall of the rear end of the filter outer barrel 9 is fixedly connected with a water outlet seat 8. The rear end of the filter outer barrel 9 is fixedly connected with the second mounting frame 6 by bolts. The rear end of the water outlet seat 8 penetrates the second mounting frame 6 and extends to the second mounting frame 6. On the outside of the second mounting bracket 6, the front end of the filter outer barrel 9 is fixedly connected to the first mounting bracket 5 through bolts. Through the bolted connection, the filter outer barrel 9 can be quickly fixed to the first mounting bracket 5 and the second mounting bracket 6. The outer walls of the second filter frame 18 are each provided with a plurality of long limiting slots 19 , and the outer walls of the first filter frame 14 are fixedly connected with a plurality of long limiting rods 17 . The long limiting rods 17 are located between the long limiting slots 19 Internal sliding connection, the outer wall of the second support ring 28 is fixedly connected to the inner wall of the first support ring 21, the outer wall of the front end of the filter barrel 9 is fixedly connected with a sealing cover 38 through bolts, the sealing cover 38, the outer wall of the front end of the sealing cover 38 is fixedly connected There is a water inlet seat 39, and a water collection chamber 40 is provided inside the sealing cover 38. A diverter ring 41 is fixedly connected to the edge of the water collection chamber 40, and a plurality of diverter holes 42 are provided on the side walls of the diverter ring 41. The sealing cover 38 A plurality of water injection heads 43 are provided at the edges of the water injection heads 43 , and water injection nozzles 44 are fixedly connected to the rear ends of the water injection heads 43 .

Working principle: When installing the low-pressure and high-efficiency nanofiltration device, first insert the filter outer barrel 9 through the first installation frame 5. At this time, the filter outer barrel 9 slides on the upper end of the support frame 2 until it is inserted into the inside of the positioning circular groove 7. At this time, the filter outer barrel 9 is fixed to the first mounting frame 5 and the second mounting frame 6 through bolts. At this time, the first filter frame 14 is inserted into the inside of the filter outer barrel 9. At this time, the limiting block 15 is inserted into the limiting cover. 13, then insert the second filter frame 18. At this time, the long limit rod 17 slides inside the long limit groove 19. At this time, the installation sleeve 25 is set on the outer wall of the support rod 22 through the installation ring 24. At this time, the first sliding groove 23, the second sliding groove 26 and the third sliding groove 35 are on the same horizontal line. Then insert the third filter frame 29 into the inside of the filter barrel 9. At this time, the sliding plate 31 is in the first sliding groove 23. , the interior of the second sliding groove 26 and the third sliding groove 35 slides and limits the third filter frame 29, and then the sealing cover 38 is fixed to the front end of the filter outer barrel 9 through bolts. At this time, the low-pressure and high-efficiency nanofiltration device When starting to use, put the water to be filtered into the water collecting chamber 40 through the water inlet seat 39. At this time, the water to be filtered enters the inside of the water injection head 43 through the diverter ring 41 and the diverter hole 42. At this time, the water to be filtered passes through the water injection nozzle 44. A batch of water enters the inside of the connecting pipe 11, and then sprays out evenly toward the inside of the filter barrel 9 through multiple water spray heads 12. The water to be filtered can be preliminarily filtered through the coarse filter layer 16 to remove larger impurities and At the same time, the coarse filter layer 16 is provided with multiple uniform filtrations that can achieve multi-directional uniform filtration. The activated carbon filter layer 20 can filter and reduce organic solutes, residual chlorine and odor substances in the water, and then through the medium filter layer 27 and The precision filtration layer 30 can be used to remove tiny particles, colloids, bacteria, etc. At the same time, the nanofiltration layer 32 uses nanofiltration membrane as the filter medium, which can remove smaller particles, ions, organic matter, viruses, bacteria, etc., while the ion exchange layer 33 Ion exchange resin is used to remove ionic pollutants in the water, such as hardness ions and metal ions, and the finally filtered water is discharged outward through the water outlet seat 8 .

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

Claims (8)

1. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water, including a base (1), a first filter frame (14), a second filter frame (18), and a mounting ring (24), and is characterized by: Three supporting frames (2) are fixedly connected to the middle part of the upper surface of the base (1), and a first mounting frame (5) is fixedly connected to the front end of the upper surface of the base (1). A second mounting bracket (6) is fixedly connected to the rear end of the second mounting bracket (6). A positioning circular groove (7) is provided in the middle of the outer wall of the front end of the second mounting bracket (6). The first mounting bracket (5) and the second mounting bracket are The middle part of the frame (6) is equipped with a filter outer barrel (9); The inner wall of the filter outer barrel (9) is provided with a plurality of placement slots (10), and the side walls of the filter outer barrel (9) are provided with a plurality of connecting pipes (11). The connecting pipes (11) All extend to the inside of the placement tank (10), the tube body of the connecting pipe (11) is fixedly connected with a plurality of water spray heads (12), and the inner wall of the filter outer barrel (9) is fixedly connected with a plurality of water spray heads (12). Limiting cover (13), the outer wall of the first filter frame (14) is fixedly connected with a plurality of limiting blocks (15), and the limiting blocks (15) are snap-fitted with the limiting cover (13) , the side walls of the first filter frame (14) are fixedly connected with multiple coarse filter layers (16), and the side walls of the second filter frame (18) are fixedly connected with multiple activated carbon filter layers (20) ; A first support ring (21) is fixedly connected to the inner wall of the rear end of the filter outer barrel (9), and a plurality of support rods (22) are fixedly connected to the outer wall of the front end of the first support ring (21). The support rods (22) A first sliding groove (23) is provided at one end close to the center of the filter barrel (9), and a plurality of installation sleeves (25) are fixedly connected to the outer wall of the rear end of the installation ring (24). A second sliding groove (26) is provided at one end of the sleeve (25) close to the center of the filter outer barrel (9). The installation sleeve (25) is sleeved on the outer wall of the support rod (22). The installation sleeve (25) is 25) are fixedly connected to the medium-sized filter layer (27), and the inner wall of the rear end of the filter outer barrel (9) is fixedly connected to a second support ring (28), and the interior of the second support ring (28) is snap-fitted It is equipped with a third filter frame (29). The outer walls of the third filter frame (29) are fixedly connected with a plurality of sliding plates (31). The upper surface of the mounting ring (24) is provided with a plurality of third filter frames (29). Sliding groove (35), the sliding plates (31) are all slidingly connected inside the first sliding groove (23), the second sliding groove (26) and the third sliding groove (35), and the third filter frame ( A plurality of precision filter layers (30) are fixedly connected to the side walls of 29), a nanofiltration layer (32) is fixedly connected to the inner wall of the third filter frame (29), and the inner wall of the nanofiltration layer (32) is fixed Attached is an ion exchange layer (33). 2. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 1, characterized in that: a positioning cover (36) is fixedly connected to the center of the inner wall of the rear end of the filter outer barrel (9). ), the outer wall of the positioning cover (36) is provided with positioning semi-arc grooves (37), and the inner wall of the rear end of the third filter frame (29) is fixedly connected with a plurality of positioning posts (34). The positioning posts (34) are all snap-fitted with the positioning half-arc groove (37). 3. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 1, characterized in that: the upper ends of the support frames (2) are provided with support arc grooves (3), so A plurality of balls (4) are rotatably connected to the bottom surface of the supporting arc-shaped groove (3), and the balls (4) are slidingly connected to the lower surface of the filter outer barrel (9). 4. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 1, characterized in that: a water outlet seat (8) is fixedly connected to the middle part of the outer wall of the rear end of the filter outer barrel (9). , the rear end of the filter outer barrel (9) is fixedly connected to the second mounting bracket (6) through bolts, and the rear end of the water outlet seat (8) penetrates the second mounting bracket (6) and extends to the second mounting bracket (6), the front end of the filter outer barrel (9) is fixedly connected to the first mounting bracket (5) through bolts. 5. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 1, characterized in that: the outer wall of the second filter frame (18) is provided with a plurality of long limit slots ( 19), the outer wall of the first filter frame (14) is fixedly connected with a plurality of long limiting rods (17), and the long limiting rods (17) are all slidingly connected inside the long limiting groove (19). . 6. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 1, characterized in that: the outer wall of the second support ring (28) and the inner wall of the first support ring (21) Fixed connection. 7. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 1, characterized in that: the outer wall of the front end of the filter outer barrel (9) is connected with a sealing cover (38) through bolts. , the sealing cover (38), the outer wall of the front end of the sealing cover (38) is fixedly connected with a water inlet seat (39), and a water collection chamber (40) is provided inside the sealing cover (38). A shunt ring (41) is fixedly connected to the edge of the water chamber (40), and a plurality of shunt holes (42) are provided on the side walls of the shunt ring (41). 8. A low-pressure and high-efficiency nanofiltration device used in the preparation of ultrapure water according to claim 7, characterized in that: multiple water injection heads (43) are provided at the edges of the sealing cover (38), The rear ends of the water injection heads (43) are fixedly connected with water injection nozzles (44).