Reverse osmosis membrane filter element and water purifier

Abstract

The invention relates to the technical field of water purification equipment, particularly provides a reverse osmosis membrane filter element and a water purifier, and aims to solve the problems that the amount of waste water generated after raw water of an existing water purifier passes through a reverse osmosis membrane is large, namely, the purification-waste ratio is low, and the waste water discharge amount is too large, so that unnecessary waste of water resources is caused. In order to achieve the purpose, the reverse osmosis membrane filter element comprises a first filter element and a second filter element, the first filter element is nested on the outer side of the second filter element and is detachably connected with the second filter element, and wastewater generated by filtration of the first filter element is subjected to secondary filtration through the second filter element and then is discharged from a wastewater port. According to the reverse osmosis membrane filter element designed by the invention, wastewater generated after raw water is filtered by the first filter element is filtered again by the second filter element, and a part of pure water is generated again, so that the wastewater discharge is reduced, the wastewater ratio is increased, the purpose of double filtration is realized, and the waste of water resources is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of water purification equipment, and specifically provides a reverse osmosis membrane filter element and a water purifier. Background Art

[0002] Generally, water purifiers combine different types of filter elements in a composite way to improve the water purification effect. With the development of technology, the mainstream water purifiers on the market currently use reverse osmosis technology. The filter element configuration is generally a PP cotton filter element combined with a pre-activated carbon filter element, a reverse osmosis membrane filter element, and a post-activated carbon filter element. The raw water first passes through the pre-filter element, and then the concentrated water (also called wastewater) produced after passing through the reverse osmosis membrane is discharged, and the filtered clean water passes through the post-filter element for re-filtration to form pure water.

[0003] In the above description, the amount of wastewater generated after the raw water passes through the reverse osmosis membrane filter is large, that is, the net waste ratio is low, and the excessive wastewater discharge causes unnecessary waste of water resources.

[0004] Therefore, the present invention needs to provide a new reverse osmosis membrane filter element and a water purifier to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve the above technical problem, that is, to solve the problem that the amount of wastewater generated by the existing water purifier after the raw water passes through the reverse osmosis membrane is large, that is, the net waste ratio is low, and the excessive wastewater discharge causes unnecessary waste of water resources.

[0006] To this end, in a first aspect, the present invention provides a reverse osmosis membrane filter element, comprising a first filter element and a second filter element, wherein the first filter element is nested on the outside of the second filter element and the two elements are detachably connected to each other, and a first wastewater flow channel of the first filter element is connected to a raw water inlet of the second filter element, so that the first filter element can filter the wastewater generated by filtering the raw water through the second filter element before discharging it.

[0007] When the above technical solution is adopted, the wastewater generated after the raw water is filtered by the first filter element is filtered again by the second filter element to produce a portion of pure water again, thereby reducing the amount of wastewater discharged, improving the wastewater ratio, achieving the purpose of dual filtration, and reducing the waste of water resources; and the first filter element and the second filter element can be disassembled, and the filter element with serious membrane pollution can be replaced in a targeted manner without the need for overall replacement, thereby reducing the user's cost of use.

[0008] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, the first filter element includes a first outer shell, an end cover and a first membrane assembly, the first membrane assembly includes a first central tube and a first membrane assembly, the first membrane assembly is wound on the first central tube, the end cover is connected to the first outer shell to encapsulate the first membrane assembly inside the first outer shell, and the second filter element is encapsulated inside the first central tube, and the wastewater generated after filtration by the first filter element enters the second filter element through the wastewater inlet of the first central tube.

[0009] When the above technical solution is adopted, the wastewater generated by the first filter element enters the second filter element through the wastewater inlet of the first central tube, thereby realizing the connection between the wastewater of the first filter element and the second filter element, thereby achieving the purpose of double filtration. Moreover, the second filter element is arranged in the first central tube, which is beneficial to reducing the overall volume of the reverse osmosis membrane filter element and reducing space occupancy.

[0010] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, there is a gap between the first membrane assembly and the inner side wall of the first outer shell to form a raw water flow channel, there is a gap between the first membrane assembly and the bottom wall inside the first outer shell to form a first wastewater flow channel, the first wastewater flow channel is connected to the wastewater inlet of the first center tube, a plurality of first water holes are provided on the outer peripheral wall of the first center tube, there is a gap between the inner side wall of the first center tube and the second filter element to form a first pure water flow channel, and the pure water generated after the raw water is filtered by the first membrane assembly enters the first pure water flow channel through the first water holes.

[0011] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, one end of the first central tube is provided with a mounting port for allowing the second filter element to pass through, and the other end of the first central tube is provided with the wastewater inlet, and the diameter of the wastewater inlet is smaller than the outer diameter of the second filter element.

[0012] When the above technical solution is adopted, the second filter element is installed into the first center tube through the installation port. Since the diameter of the wastewater inlet is smaller than the outer diameter of the second filter element, the second filter element abuts against the bottom end of the first center tube after installation. In this way, the second filter element can be fixed in the first center tube in combination with the end cover.

[0013] In a specific embodiment of the above reverse osmosis membrane filter element, a sealing cover plate is sleeved on the outer side of one end of the first central tube having the installation port to cover the end of the adjacent first membrane assembly so that raw water can directly enter the raw water flow channel.

[0014] When the above technical solution is adopted, the sealing cover plate covers the end of the first membrane assembly close to the end cover, so that the raw water directly enters the raw water flow channel, avoiding the raw water entering the membrane of the first membrane assembly when it first enters and failing to achieve the required filtering effect.

[0015] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, the second filter element includes a second outer shell and a second membrane assembly, the second outer shell is encapsulated in the first central tube through the end cover, the second membrane assembly is arranged in the second outer shell, the second membrane assembly includes a second central tube and a second membrane assembly, the second membrane assembly is wound on the second central tube, the interior of the second central tube is divided into two cavities that are not connected to each other, and the outer peripheral wall of the second central tube is provided with a plurality of second water holes that are distributed circumferentially and connected to the cavity close to the end cover.

[0016] When the above technical solution is adopted, the interior of the second central tube is divided into two cavities in order to separate the waste water from the filtered pure water, so that only the pure water filtered by the second membrane assembly can flow through the interior of the second central tube.

[0017] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, a gap is formed between the second membrane assembly and the second outer shell to form a second wastewater flow channel, a cavity near the end cover inside the second center tube forms a second pure water flow channel, and a first sealing ring is fixed between the outer peripheral wall of the second membrane assembly near the bottom wall of the first outer shell and the second outer shell to prevent wastewater entering from the wastewater inlet from directly entering the second wastewater flow channel.

[0018] When the above technical solution is adopted, the first sealing ring can separate the raw water of the second module assembly (i.e., the wastewater filtered by the first filter element) from the wastewater generated after filtration by the second membrane assembly, preventing the raw water from directly entering the second wastewater flow channel and flowing out without being filtered, thereby ensuring the filtering effect.

[0019] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, both ends of the second shell respectively extend outward with diversion holes, and a second sealing ring is provided on the outer peripheral wall of the diversion hole, one of the diversion holes is inserted into the wastewater inlet and the wastewater inlet and the diversion hole are sealed by the second sealing ring, and one end of the second center tube passes through the other diversion hole, so that a partial second wastewater flow channel is formed between the other diversion hole and the end of the second center tube.

[0020] In a specific embodiment of the above-mentioned reverse osmosis membrane filter element, the end cover is provided with a raw water inlet, a first pure water outlet, a second pure water outlet and a waste water outlet, the raw water inlet is connected to the raw water flow channel, the first pure water outlet is connected to the first pure water flow channel, the second pure water outlet is connected to the second pure water flow channel, and the waste water outlet is connected to the second waste water flow channel.

[0021] In a second aspect, the present invention further provides a water purifier, on which is installed a reverse osmosis membrane filter element as described in any one of the above technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0023] Figure 1 This is an overall appearance diagram of the reverse osmosis membrane filter element provided by the present invention;

[0024] Figure 2 It is an overall exploded view of the reverse osmosis membrane filter element provided by the present invention;

[0025] Figure 3 is an overall cross-sectional view of the reverse osmosis membrane filter element provided by the present invention;

[0026] Figure 4 is a schematic structural diagram of the first membrane module;

[0027] Figure 5 is a cross-sectional view of the first filter element;

[0028] Figure 6 This is the external structure diagram of the second filter element;

[0029] Figure 7 is a cross-sectional view of the second filter element;

[0030] Figure 8 It is a schematic diagram of the flow direction of each flow channel;

[0031] Fig. 9 is a schematic diagram of the expansion of the first membrane module;

[0032] Fig.10 Schematic diagram of the expansion of the second membrane module.

[0033] List of reference numerals:

[0034] 1. Second filter element; 11. Second housing; 12. Second membrane assembly; 121. Second diaphragm assembly; 122. Second center tube; 2. First filter element; 21. End cover; 211. Raw water inlet; 212. First pure water outlet; 213. Second pure water outlet; 214. Waste water outlet; 22. First housing; 23. First membrane assembly; 231. First center tube; 232. First diaphragm assembly; 3. Sealing cover; 4. Guide hole; 5. Separation block; 6. First sealing ring; 7. First water hole; 8. Waste water inlet; 9. First waste water flow channel; 10. Raw water flow channel; 101. First pure water flow channel; 102. Second waste water flow channel; 103. Second pure water flow channel; 104. Back side; 105. Front side. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not used to limit the scope of protection of the present invention. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0036] It should be noted that in the description of the present invention, the terms "upper", "lower", "inner", "outer", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the relevant devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, ordinal numbers "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Based on the technical problem described in the background technology, the existing water purifier has a large amount of wastewater generated after the raw water passes through the reverse osmosis membrane, that is, the net waste ratio is low, and the excessive wastewater discharge causes unnecessary waste of water resources.

[0039] To solve the above technical problems, see Figure 1-3 The present invention provides a reverse osmosis membrane filter element, which includes a first filter element 2 and a second filter element 1. The first filter element 2 is nested outside the second filter element 1 and is detachably connected to each other. The first wastewater flow channel of the first filter element is connected to the raw water inlet of the second filter element, so that the wastewater (also called concentrated water) generated by the first filter element 2 is filtered and then discharged after passing through the second filter element 1. By filtering the wastewater generated by the first filter element 2 again, a part of pure water can be generated again, which reduces the wastewater discharge and helps to avoid the waste of water resources.

[0040] In one embodiment, see Figure 3-5The first filter element 2 includes a first shell 22, an end cover 21 and a first membrane assembly 23. The first membrane assembly 23 includes a first central tube 231 and a first diaphragm assembly 232. The first diaphragm assembly 232 is wound on the first central tube 231. The end cover 21 is connected to the first shell 22 to encapsulate the first membrane assembly 23 inside the first shell 22, and to encapsulate the second filter element 1 inside the first central tube 231. The wastewater generated after filtration by the first filter element 2 enters the second filter element 1 through the wastewater inlet 8 of the first central tube 231.

[0041] Specifically, the first diaphragm assembly 232 is in an unfolded state, folded along the front side 105 of the diaphragm, the wastewater diversion net and the clean water diversion net are placed on the front side 105 and the back side 104 of the diaphragm respectively, and after being neatly stacked, the back side 104 of the diaphragm is sealed with glue, and the glue sealing position forms a U-shape with the opening facing the first central tube 231, and the glue sealing position on the front side 105 of the diaphragm is glued and sealed along the long side direction of the diaphragm, and then rolled up in the same direction to form the first membrane assembly 23, and the glued position is Fig. 9 The end cover 21 and the first housing 22 can be disassembled to facilitate replacement of the internal membrane assembly.

[0042] In the above embodiment, the wastewater generated by the first filter element 2 enters the second filter element 1 through the wastewater inlet 8 of the first central tube 231, thereby realizing the connection between the wastewater of the first filter element 2 and the second filter element 1, thereby achieving the purpose of double filtration, and the second filter element 1 is arranged in the first central tube 231, which is beneficial to reducing the overall volume of the reverse osmosis membrane filter element and reducing space occupancy.

[0043] In one embodiment, see Figure 8 There is a gap between the first membrane assembly 23 and the inner wall of the first outer shell 22 to form a raw water flow channel 10, there is a gap between the first membrane assembly 23 and the bottom wall inside the first outer shell 22 to form a first wastewater flow channel 9, the first wastewater flow channel 9 is connected to the wastewater inlet 8 of the first center tube 231, a plurality of first water holes 7 are provided on the outer peripheral wall of the first center tube 231, there is a gap between the inner wall of the first center tube 231 and the second filter element 1 to form a first pure water flow channel 101, and the pure water generated after the raw water is filtered by the first membrane assembly 23 enters the first pure water flow channel 101 through the first water holes 7.

[0044] Specifically, an annular protrusion extends outward from the inner wall of the first outer shell 22 near the bottom of the first outer shell 22. When the first membrane assembly 23 is placed on the inner side of the first outer shell 22, its outer peripheral wall rests on the annular protrusion. In this way, after the raw water enters the raw water flow channel 10, the annular protrusion can block the raw water from flowing into the first wastewater flow channel 9, so that the raw water flows in a direction perpendicular to the first center tube 231, ensuring that the raw water can be well filtered.

[0045] In addition, a plurality of circumferentially distributed support blocks are fixed on the bottom wall of the first housing 22, and the bottom end of the first membrane assembly 23 is against the support blocks so that there is a gap between the first membrane assembly 23 and the bottom wall of the first housing 22, and a first wastewater flow channel 9 is formed between adjacent support blocks. Specifically, a groove is provided on the bottom wall of the first housing 22, and the support blocks are fixed on the bottom wall of the first housing 22 outside the groove, so that the gaps between adjacent support blocks and the groove form the first wastewater flow channel 9, so that the wastewater converges into the groove and easily enters the second filter element 1.

[0046] In the above embodiment, a first water hole 7 is provided on the outer peripheral wall of the first central tube 231, so that the pure water generated after filtering the raw water enters the gap between the first central tube 231 and the second filter element 1 through the first water hole 7, thereby achieving the purpose of discharging the pure water through the first pure water channel 101.

[0047] In one embodiment, one end of the first central tube 231 is provided with a mounting port for passing the second filter element 1 , and the other end of the first central tube 231 is provided with a wastewater inlet 8 , the diameter of which is smaller than the outer diameter of the second filter element 1 .

[0048] In the above embodiment, the second filter element 1 is installed into the first center tube 231 through the installation port. Since the diameter of the wastewater inlet 8 is smaller than the outer diameter of the second filter element 1, the second filter element 1 abuts against the bottom end of the first center tube 231 after being installed. In this way, the second filter element 1 can be fixed in the first center tube 231 in combination with the end cover 21.

[0049] In one embodiment, a sealing cover plate 3 is sleeved on the outer side of one end of the first central tube 231 provided with the installation opening to cover the end of the adjacent first membrane assembly 23 so that the raw water can directly enter the raw water flow channel 10 .

[0050] Specifically, a third sealing ring is installed on the outer peripheral wall of the installation port for sealing with the end cover 21, and a sealing cover plate 3 is added to cover the end of the first membrane assembly 23 close to the end cover 21 to prevent the raw water from entering the membrane of the first membrane assembly 23 when it starts to enter and failing to achieve the required filtering effect. In this way, the raw water can only flow along the raw water flow channel 10 after entering, and the third sealing ring serves the purpose of isolating the pure water from the raw water.

[0051] In one embodiment, see Figure 3 , Figure 6 and Figure 7The second filter element 1 includes a second outer shell 11 and a second membrane assembly 12. The second outer shell 11 is encapsulated in the first central tube 231 through the end cover 21. The second membrane assembly 12 is arranged in the second outer shell 11. The second membrane assembly 12 includes a second central tube 122 and a second diaphragm assembly 121. The second diaphragm assembly 121 is wound on the second central tube 122. The interior of the second central tube 122 is divided into two cavities that are not connected to each other. A plurality of second water holes distributed circumferentially and connected to the cavity near the end cover 21 are provided on the outer peripheral wall of the second central tube 122.

[0052] Specifically, a partition block 5 is fixed inside the second central tube 122 to divide the interior of the second central tube 122 into two cavities, in order to separate the wastewater from the filtered pure water, so that only the pure water filtered by the second membrane assembly 12 can flow through the second central tube 122. Of course, it can be understood that the partition block 5 can also be fixed at the end of the second central tube 122 near the wastewater inlet 8, which is also within the scope of protection of the present invention. The wastewater formed after filtration by the first filter element 2 enters the second membrane assembly 12 for filtration, and the pure water generated after filtration enters one of the cavities through the second water hole and is discharged.

[0053] In addition, the second diaphragm assembly 121 is in an unfolded state, folded along the front side 105 of the diaphragm, the wastewater diversion net and the clean water diversion net are placed on the front side 105 and the back side 104 of the diaphragm respectively, and glue is applied after being neatly stacked. A U-shape with an opening toward the first central tube 231 is formed at the glue sealing position on the back side 104 of the diaphragm, and glue is applied along the short side direction of the diaphragm at the glue sealing position on the front side 105 of the diaphragm, and then rolled up in the same direction to form the first membrane assembly 23, and the glue application position is Fig.10 The shaded area shown in .

[0054] In one embodiment, see Figure 8 There is a gap between the second membrane assembly 12 and the second outer shell 11 to form a second wastewater flow channel 102, and the cavity inside the second center tube 122 near the end cover 21 forms a second pure water flow channel 103. A first sealing ring 6 is fixed between the outer peripheral wall of the second membrane assembly 12 near the bottom wall of the first outer shell 22 and the second outer shell 11 to prevent the wastewater entering from the wastewater inlet 8 from directly entering the second wastewater flow channel 102.

[0055] In the above embodiment, the first sealing ring 6 can separate the raw water of the second module assembly (i.e., the wastewater filtered by the first filter element 2) from the wastewater generated after filtration by the second membrane assembly 12, thereby preventing the raw water from directly entering the second wastewater flow channel 102 and flowing out without being filtered, thereby ensuring the filtering effect.

[0056] In one embodiment, both ends of the second shell 11 respectively extend outward with guide holes 4, and a second sealing ring is provided on the outer peripheral wall of the guide hole 4. One of the guide holes 4 is inserted into the wastewater inlet 8 and the wastewater inlet 8 and the guide hole 4 are sealed by the second sealing ring to separate the wastewater inlet 8 from the first pure water flow channel 101. The guide hole 4 is the raw water inlet of the second filter element, and one end of the second center tube 122 passes through the other guide hole 4, so that a part of the second wastewater flow channel 102 is formed between the other guide hole 4 and the end of the second center tube 122.

[0057] Specifically, the second housing 11 is formed by aligning and splicing two half housings, so that the second membrane assembly 12 can be encapsulated in the second housing 11 .

[0058] In one embodiment, a raw water inlet 211, a first pure water outlet 212, a second pure water outlet 213 and a waste water outlet 214 are provided on the end cover 21. The raw water inlet 211 is connected to the raw water channel 10, the first pure water outlet 212 is connected to the first pure water channel 101, the second pure water outlet 213 is connected to the second pure water channel 103, and the waste water outlet 214 is connected to the second waste water channel 102.

[0059] Specifically, a first annular ring, a second annular ring and a third annular ring are fixed on the top wall inside the end cover 21 in sequence from the inside to the outside along the radial direction. The first annular ring is sleeved on the end of the second center tube 122, and a fourth sealing ring is arranged between the end and the first annular ring for sealing to separate the second pure water flow channel 103 from the second waste water flow channel 102. A second pure water outlet 213 is connected to the top of the end cover 21 and the corresponding part of the inside of the second annular ring; the second annular ring is sleeved on the outside of the guide hole 4 of the second shell 11 close to the end cover 21 and is connected to the second waste water flow channel 102. The second wastewater channel 102 is sealed by a second sealing ring to separate the first pure water channel 101, and the wastewater outlet 214 is connected to the interior of the second annular ring; the third annular ring is sleeved on the outside of the installation port of the first center tube 231, and is sealed by a third sealing ring to separate the first pure water channel 101 from the raw water channel 10, and the first pure water outlet 212 is connected to the interior of the third annular ring; the gap between the side wall of the end cover 21 and the third annular ring is connected to the raw water channel 10 for introducing raw water entering from the raw water inlet 211.

[0060] In addition, after the end cover 21 is connected to the first shell 22, the third annular ring on the end cover 21 applies pressure to the sealing cover plate 3 to fix it, and the second annular ring fixes the second shell 11 in the first center tube 231, thereby realizing the function of fixing the first module assembly and the second filter element 1 through the connection between the end cover 21 and the first shell 22.

[0061] The working principle of the present invention is explained in the direction of the arrow shown in Figure 8. Raw water enters the raw water flow channel 10 through the raw water input port 211, and is filtered in a direction perpendicular to the center line of the first central tube 231 during the flow process. The pure water produced after filtration is discharged through the first pure water flow channel 101 and the first pure water outlet 212, and the waste water produced after filtration by the first filter element 2 flows into the first waste water flow channel 9, and then enters the second central tube 122 through the waste water inlet 8 and the guide hole 4 along the flow channel in the center line direction to be filtered through the second membrane assembly 12, and the filtered pure water enters the second pure water flow channel 103 through the second water hole and is discharged through the second pure water outlet 213, and the waste water produced by filtration is discharged through the second waste water flow channel 102 and the waste water outlet 214, thereby realizing secondary filtration of the waste water.

[0062] In a second aspect, the present invention further provides a water purifier, on which is installed a reverse osmosis membrane filter element as described in any one of the above technical solutions.

[0063] In the above-mentioned various embodiments and various expanded implementation methods, the wastewater generated after the raw water is filtered through the first filter element is filtered again through the second filter element to produce a portion of pure water again, thereby reducing the amount of wastewater discharged, improving the wastewater ratio, achieving the purpose of dual filtration, and reducing the waste of water resources; and the first filter element and the second filter element can be disassembled, and the filter element with serious membrane pollution can be replaced in a targeted manner without the need for overall replacement, thereby reducing user usage costs.

[0064] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A reverse osmosis membrane filter element, characterized in that: The reverse osmosis membrane filter element includes a first filter element and a second filter element. The first filter element is nested on the outside of the second filter element and is detachably connected to each other. The first wastewater flow channel of the first filter element is connected to the raw water inlet of the second filter element, so that the first filter element can filter the wastewater generated by the raw water filtration through the second filter element before discharging it.

2. The reverse osmosis membrane filter element according to claim 1, characterized in that: The first filter element includes a first shell, an end cover and a first membrane assembly, the first membrane assembly includes a first center tube and a first membrane assembly assembly, the first membrane assembly is wound on the first center tube, the end cover is connected to the first shell to encapsulate the first membrane assembly inside the first shell, and the second filter element is encapsulated inside the first center tube, and the wastewater generated after filtration by the first filter element enters the second filter element through the wastewater inlet of the first center tube.

3. The reverse osmosis membrane filter element according to claim 2, characterized in that: There is a gap between the first membrane assembly and the inner side wall of the first shell to form a raw water flow channel, there is a gap between the first membrane assembly and the bottom wall inside the first shell to form a first wastewater flow channel, the first wastewater flow channel is connected to the wastewater inlet of the first center tube, a plurality of first water holes are provided on the outer peripheral wall of the first center tube, there is a gap between the inner side wall of the first center tube and the second filter element to form a first pure water flow channel, and the pure water generated after the raw water is filtered by the first membrane assembly enters the first pure water flow channel through the first water holes.

4. The reverse osmosis membrane filter element according to claim 2, characterized in that: One end of the first central tube is provided with a mounting port for allowing the second filter element to pass through, and the other end of the first central tube is provided with the wastewater inlet, and the diameter of the wastewater inlet is smaller than the outer diameter of the second filter element.

5. The reverse osmosis membrane filter element according to claim 3, characterized in that: A sealing cover plate is sleeved on the outer side of one end of the first central tube provided with the installation opening to cover the end of the first membrane assembly adjacent thereto so that raw water can directly enter the raw water flow channel.

6. The reverse osmosis membrane filter element according to claim 3, characterized in that: The second filter element includes a second outer shell and a second membrane assembly, the second outer shell is encapsulated in the first central tube through the end cover, the second membrane assembly is arranged in the second outer shell, the second membrane assembly includes a second central tube and a second diaphragm assembly, the second diaphragm assembly is wound on the second central tube, the interior of the second central tube is divided into two cavities that are not connected to each other, and the outer peripheral wall of the second central tube is provided with a plurality of second water holes that are distributed circumferentially and connected to the cavity close to the end cover.

7. The reverse osmosis membrane filter element according to claim 6, characterized in that: There is a gap between the second membrane assembly and the second outer shell to form a second wastewater flow channel, and the cavity inside the second center tube near the end cover forms a second pure water flow channel. A first sealing ring is fixed between the outer peripheral wall of the second membrane assembly near the bottom wall of the first outer shell and the second outer shell to prevent wastewater entering from the wastewater inlet from directly entering the second wastewater flow channel.

8. The reverse osmosis membrane filter element according to claim 7, characterized in that: Both ends of the second shell are respectively provided with guide holes extending outward, and the outer peripheral walls of the guide holes are provided with second sealing rings, one of the guide holes is inserted into the wastewater inlet and the wastewater inlet and the guide hole are sealed by the second sealing ring, and one end of the second center tube passes through the other guide hole, so that a partial second wastewater flow channel is formed between the other guide hole and the end of the second center tube.

9. The reverse osmosis membrane filter element according to claim 7, characterized in that: The end cover is provided with a raw water inlet, a first pure water outlet, a second pure water outlet and a waste water outlet. The raw water inlet is connected to the raw water flow channel, the first pure water outlet is connected to the first pure water flow channel, the second pure water outlet is connected to the second pure water flow channel, and the waste water outlet is connected to the second waste water flow channel.

10. A water purifier, characterized in that: The water purifier is installed with a reverse osmosis membrane filter element as described in any one of claims 1 to 9.

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