Membrane element, preparation method thereof, filter element and water purifier

Abstract

The present invention discloses a membrane element, comprising a base layer, a loose support layer and a thin film layer laid in sequence, wherein a plurality of water-permeable protrusions are provided on the side of the base layer facing the thin film layer and the side of the loose support layer facing away from the base layer; the protrusions on the base layer are located on the surface of the membrane element, and can separate two adjacent layers of membrane elements when the membrane element is wound around the central tube to form an axial water flow path. This membrane element replaces the traditional water inlet screen and water production screen with the protrusions on its own surface. The protrusions retain the permeability (water permeability), which not only increases the membrane area to a certain extent, but also achieves the effect of reducing the gap between the diaphragms and reducing the water flow resistance, greatly reducing the pressure drop and the occurrence of particle capture, and improving the service life of the membrane element. The present invention proposes a method for preparing a membrane element. The present invention also proposes a filter element and a water purifier. The use of the above-mentioned membrane element greatly improves the water production and water production rate of the membrane element.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane elements, and in particular to a membrane element and a preparation method thereof, a filter element and a water purifier. Background Art

[0002] Currently, conventional membrane element cartridges, such as reverse osmosis (RO) membrane cartridges, are constructed by wrapping RO membrane sheets, inlet screens, and product screens around a central tube. The inlet screens form a laminated structure with the RO membrane sheets, separating adjacent sheets through the inlet screens to create a flow path for fluid to flow axially through the membrane element. The product screens are used to divert fluid from the membranes to the central tube, allowing fluid to permeate the RO membranes and flow through the product screens into the central tube. While this screen is necessary to maintain open and uniform axial flow between the laminated structure, it also creates flow restriction and pressure drop within the axial flow path. Because conventional RO membranes utilize both inlet and product screens, both of which are grid-like structures laid flat between the two membrane sheets, water must penetrate the screens to form a path. Consequently, the screens restrict water flow within the flow path and create contact areas with the membrane, increasing pressure drop. This can lead to biological growth, scale formation, and significant particle capture at the screens, accelerating membrane fouling. At the same time, due to various limitations such as water flow resistance, processing and material properties, the thickness of the water inlet screen and the water production screen is limited and cannot be thinner, resulting in a waste of space and reduced water production efficiency.

[0003] Therefore, it is necessary to further improve and upgrade the membrane elements in view of the defects of the above-mentioned prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a membrane element and its preparation method, filter element and water purifier to solve the problem that the partition structure of the above-mentioned traditional membrane elements will restrict the water flow in the flow channel and form an area in contact with the membrane, thereby increasing the pressure drop and accelerating membrane fouling.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a membrane element, comprising a base layer, a loose support layer and a thin film layer laid in sequence, wherein a plurality of water-permeable protrusions are provided on the side of the base layer facing the thin film layer and on the side of the loose support layer facing away from the base layer; wherein the protrusions provided on the side of the base layer facing the thin film layer can separate two adjacent layers of the membrane elements when the membrane element is wound around a central tube, so as to form an axial water flow path.

[0007] Optionally, the membrane element is a reverse osmosis membrane or a nanofiltration membrane.

[0008] Optionally, when the membrane element is a reverse osmosis membrane, the base layer is a polyester non-woven fabric base layer, the loose support layer is a polysulfone support layer, and the film layer is a polyacrylamide layer.

[0009] Optionally, when the membrane element is a nanofiltration membrane, the base layer is a polyester non-woven fabric base layer, the loose support layer is a polysulfone support layer, and the thin film layer is a polyamide layer.

[0010] Optionally, the loose supporting layer and the film layer are laid on both sides of the base layer from inside to outside; and a plurality of protrusions are provided on both sides of the base layer and on a side of any one of the loose supporting layers facing away from the base layer.

[0011] Optionally, the protrusions are dot-shaped protrusions, and a plurality of the dot-shaped protrusions on the base layer and a plurality of the dot-shaped protrusions on the loose support layer are arranged in a dot matrix structure;

[0012] Alternatively, the protrusions are discontinuous linear protrusions, and a plurality of the discontinuous linear protrusions on the base layer and a plurality of the discontinuous linear protrusions on the loose support layer are arranged in a linear array structure;

[0013] Alternatively, the protrusions are a combination of dot-shaped protrusions and discontinuous linear protrusions, and the plurality of protrusions on the base layer and the plurality of protrusions on the loose supporting layer are arranged in a dot-line matrix structure.

[0014] Optionally, the protrusions are continuous line protrusions, and the plurality of continuous line protrusions on the base layer and the plurality of continuous line protrusions on the loose support layer are arranged in a line matrix structure.

[0015] Optionally, the continuous line protrusions are straight line protrusions and / or wavy line protrusions.

[0016] Optionally, the protrusion height is smaller than the thickness of the water inlet screen and the water production screen.

[0017] At the same time, the present invention proposes a preparation method based on the above membrane element, comprising:

[0018] Directly composite-processing the thin film layer, the loose support layer having the protrusions, and the base layer having the protrusions to form the membrane element;

[0019] Alternatively, after the base layer and the loose support layer are composite-processed to form a combination, the protrusions are processed on the combination; and then the combination with the protrusions is composite-processed with the thin film layer to form the membrane element;

[0020] Alternatively, after the base layer, the loose support layer and the thin film layer are compositely processed to form a membrane element preform, the protrusions are processed on the membrane element preform to form the membrane element.

[0021] At the same time, the present invention proposes a filter element, comprising a central tube and the membrane element as described above, wherein the membrane element is wound around the outer circumference of the central tube to form a rolled laminated structure.

[0022] At the same time, the present invention provides a water purifier, including a filter element, wherein the filter element includes the membrane element as described above.

[0023] Compared with the prior art, the present invention has achieved the following technical effects:

[0024] The membrane element proposed in the present invention includes a base layer, a loose support layer and a thin film layer laid in sequence, and a plurality of water-permeable protrusions are provided on the side of the base layer facing the thin film layer and the side of the loose support layer facing away from the base layer; the protrusions on the base layer are located on the surface of the membrane element, and can separate the two adjacent membrane elements when the membrane element is wound around the central tube to form an axial water flow path. This membrane element replaces the traditional water inlet screen and water production screen with the protrusions on its own surface. The protrusion structure retains permeability (water permeability), which not only increases the membrane area to a certain extent, but also achieves the effect of reducing the gap between the membrane sheets and reducing the water flow resistance. Therefore, the protrusion is an open passage and does not form a closed space, which greatly reduces the pressure drop and the occurrence of particle capture, and increases the service life of the membrane element. It is suitable for reverse osmosis or nanofiltration. In summary, the present invention solves the problem that the screen structure existing in traditional membrane elements will restrict water flow in the flow channel and form an area in contact with the membrane, thereby increasing the pressure drop and accelerating membrane fouling.

[0025] In the membrane element of the present invention, the height of the protrusion is less than the thickness of the water inlet screen and the water production screen in the traditional diaphragm. When the membrane element is arranged in a roll-type laminated arrangement, the gap between the membranes can be reduced, which can meet the water flow path for normal operation of the membrane. At the same time, under the same pressure conditions, the diaphragm gap is reduced, the water flow path is reduced, and the water flow rate is increased. During operation, the water flow will have a flushing effect on the membrane surface, which will effectively increase the service life of the membrane element. In addition, due to the water inlet screen and the water production screen, the gap between two adjacent membranes in the traditional membrane element is relatively large. However, the height of the protrusion in the present invention is less than the thickness of the water inlet screen and the water production screen in the traditional diaphragm, and the gap between the membranes is reduced. With the same volume of membrane element, the present invention can be wound with more turns of membrane element, thereby increasing the surface area of the membrane element and improving the water production of the membrane element.

[0026] The preparation method of the membrane element proposed in the present invention does not directly spray, print or deposit protrusions on the surface of the membrane element. If the protrusions are set by spraying, printing or depositing, the attachments on the membrane surface will occupy the surface area of the membrane element and reduce the area of the membrane element. The present invention directly processes the protrusions on the diaphragm, that is, the protrusions and the diaphragm are integrally formed without adding any additional substances. The surface area of the membrane element is not affected. On the contrary, the protrusions are still permeable, which will increase the membrane area to a certain extent and improve the water production efficiency of the membrane element.

[0027] The filter element and water purifier proposed in the present invention, using the above-mentioned membrane element, can greatly improve the water production and water production rate of the membrane element, and at the same time can improve the anti-fouling and clogging ability of the membrane itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic structural diagram of a membrane element disclosed in an embodiment of the present invention;

[0030] Figure 2 A schematic cross-sectional view of a membrane element disclosed in an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the installation structure of the membrane element disclosed in an embodiment of the present invention;

[0032] Figure 4 A schematic structural diagram of a membrane element based on a lattice protrusion structure disclosed in an embodiment of the present invention;

[0033] Figure 5 、 Figure 6 and Figure 7 Schematic diagrams of the structures of three different types of membrane elements based on linear array protrusion structures disclosed in the embodiments of the present invention;

[0034] Figure 8 A schematic structural diagram of a membrane element based on a point and line array convex structure disclosed in an embodiment of the present invention;

[0035] Figure 9 A schematic structural diagram of a membrane element based on a linear protrusion array structure disclosed in an embodiment of the present invention;

[0036] Figure 10 This is a schematic structural diagram of a membrane element based on a wavy line protrusion array structure disclosed in an embodiment of the present invention.

[0037] Wherein, the accompanying drawings are marked as follows:

[0038] 100. Membrane element;

[0039] 1. Grassroots;

[0040] 2. Loose support layer;

[0041] 3. Thin film layer;

[0042] 4. Raised; 41. Point-shaped raised; 42. Intermittent linear raised; 43. Continuous linear raised;

[0043] 200. Center tube. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] One of the purposes of the present invention is to provide a membrane element to solve the problem that the spacer structure of traditional membrane elements restricts water flow in the flow channel and forms an area in contact with the membrane, thereby increasing pressure drop and accelerating membrane fouling.

[0046] Another object of the present invention is to provide a preparation method based on the above membrane element.

[0047] Another object of the present invention is to provide a filter element comprising the above membrane element.

[0048] Another object of the present invention is to provide a water purifier comprising a filter element having the above-mentioned membrane element.

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] like Figures 1 to 4As shown, this embodiment provides a membrane element 100 comprising a base layer 1, a loose support layer 2, and a thin film layer 3, which are laid in sequence. The base layer 1, facing the thin film layer 3, and the loose support layer 2, facing away from the base layer 1, are both provided with a plurality of water-permeable protrusions 4. The protrusions 4 provided on the side of the base layer 1 facing the thin film layer 3 can separate two adjacent membrane elements 100 when the membrane element 100 is wound around the central tube 200, thereby forming an axial water flow path. The thin film layer 3 is the functional layer that actually performs the separation function and is generally configured as an ultra-thin film structure with a thickness of approximately 0.2 μm (micrometers).

[0052] In this embodiment, the protrusions 4 are preferably configured as dot-shaped protrusions 41. The dot-shaped protrusions 41 on the base layer 1 and the dot-shaped protrusions 41 on the loose support layer 2 are arranged in a lattice structure. The lattice structure can be a linear matrix, thereby forming a linear matrix of protrusions on the surface of the membrane element 100. The membrane element 100 having this linear matrix of protrusions is wound around the central tube 200 to form a rolled laminate structure. The linear matrix of protrusions replaces the traditional membrane element water inlet and water production spacers, separating two adjacent membrane elements 100, providing the membrane element 100 with the required strength, while also forming a water flow path between the membrane elements 100.

[0053] like Figure 2 As shown, both sides of the base layer 1 are laid with a loose support layer 2 and a thin film layer 3 from the inside out. A number of dot-shaped protrusions 41 are provided on both sides of the base layer 1 and on the side of any loose support layer 2 facing away from the base layer 1. This forms a linear matrix of protrusions on both sides of the membrane element 100, giving the membrane element 100 a bidirectional linear matrix protrusion structure. The provision of a bidirectional linear matrix protrusion structure can further enhance the structural strength and membrane contact area of the membrane element 100 when the roll-to-roll laminate structure is formed, thereby increasing the water production and water production rate of the membrane element 100.

[0054] In this embodiment, the dot-shaped protrusions 41 may be cylindrical, prismatic, or other dot-shaped structures. Specific linear matrix methods are numerous, and simple adjustments to the matrix size or matrix method are all within the scope of protection of this technical solution.

[0055] In this embodiment, the linear matrix protrusions on the surface of the membrane element 100, on the one hand, serve to separate two adjacent membrane elements 100, and on the other hand, serve as a water flow guide path. The linear matrix protrusions of different shapes can change the water flow path in the membrane element 100, extend the water flow path, and increase the residence time of the water flow on the membrane surface.

[0056] In this embodiment, the height of the dot-shaped protrusions 41 is less than the thickness of conventional inlet and outlet screens, while still providing sufficient water flow for normal membrane operation. Therefore, under the same pressure conditions, the membrane gap is reduced, the water flow path is reduced, and the water flow velocity is increased. During operation, the water flow has a flushing effect on the membrane surface, thereby extending the service life of the membrane element 100.

[0057] In this embodiment, the membrane element 100 can be configured as a reverse osmosis membrane or a nanofiltration membrane based on the material. For example, when the membrane element 100 is used as a reverse osmosis membrane (RO), its base layer 1 is preferably a polyester non-woven fabric base layer, the loose support layer 2 is preferably a polysulfone support layer, and the thin film layer 3 is preferably a polyacrylamide layer. When the membrane element 100 is used as a nanofiltration membrane (NF), its base layer 1 is preferably a polyester non-woven fabric base layer, the loose support layer 2 is preferably a polysulfone support layer, and the thin film layer 3 is preferably a polyamide layer. Generally, the thickness of the thin film layer 3 is smaller than that of the thin film layer 3 in the reverse osmosis membrane. Both reverse osmosis membranes and nanofiltration membranes are existing filtration membrane elements. The main differences between the two are different filtration accuracy, different desalination rates, and different proportions of "wastewater" generated, which will not be elaborated here.

[0058] Conventional membrane elements have uniform thicknesses across their layers, resulting in a uniform overall thickness of the processed membrane element. The membrane element of this embodiment adjusts the local thickness (i.e., protrusions 4) of its base layer 1 and loose support layer 2 to provide the base layer 1 and loose support layer 2 with a linear matrix protrusion structure, thereby achieving the effect of having a linear matrix protrusion structure on both sides of the membrane element. The membrane element 100 provided in this embodiment, having a surface having linear matrix protrusions, replaces the traditional inlet and water production screens with linear matrix protrusions composed of dot-shaped protrusions 41 on its surface, thereby achieving the effect of reducing the diaphragm gap and lowering water flow resistance. Not only does the water production of the membrane element 100 increase significantly, but the overall membrane volume remains unchanged, resulting in minimal or no change in the amount of raw water, thereby increasing the water production rate of the membrane element.

[0059] Furthermore, conventional membrane elements utilize both inlet and outlet screens, both of which are grid-like structures laid flat between the two membrane layers. Water must penetrate the screens to form a path, restricting flow within the flow channel and increasing pressure drop. Furthermore, the screens can lead to biological growth, scale formation, and significant particle capture, accelerating membrane fouling. However, the linear matrix protrusions in this embodiment form open pathways, rather than enclosed spaces. This significantly minimizes pressure drop and particle capture, thereby extending the lifespan of the membrane element.

[0060] In addition, due to the water inlet spacer and the water production spacer, the gap between two adjacent membranes in the traditional membrane element is relatively large. For the membrane element with the same volume, the present embodiment can wind more turns of the membrane element 100, thereby increasing the surface area of the membrane element 100 and improving the water production of the membrane element 100.

[0061] Example 2

[0062] like Figures 5 to 7 As shown, this embodiment provides a membrane element 100 having a linear matrix of protrusions on its surface. The only difference between this embodiment and the first embodiment is that the protrusions 4 are provided as discontinuous linear protrusions 42. That is, the linear matrix protrusions are a linear array structure composed of discontinuous linear protrusions 42. The remaining structures and functions of the membrane element 100 are the same as those in the first embodiment and are not further described here.

[0063] In this embodiment, the intermittent linear protrusions 42 are linear protrusions, which can be as follows: Figure 5 The inclined arrangement shown can also be as shown Figure 6 intermittent linear projections 42 may also be broken line projections or curved projections, such as Figure 7 Shown is a linear matrix formed by the arrangement of broken line protrusions.

[0064] Compared to the linear matrix of dot-shaped protrusions 41 in Example 1, the linear matrix of protrusions formed by discontinuous linear protrusions 42 forms a larger membrane area and guides water flow through the membrane element 100 in a different manner. The different shapes of the linear matrix of protrusions can change the flow path within the membrane element 100, extending the flow path and increasing the residence time of water on the membrane surface.

[0065] Example 3

[0066] like Figure 8 As shown, this embodiment provides a membrane element 100 having a linear matrix of protrusions on its surface. The only difference between this embodiment and the first and second embodiments is that the protrusions 4 are a combination of dot-shaped protrusions 41 and discontinuous linear protrusions 42. That is, the linear matrix of protrusions forms a dot-line matrix structure composed of dot-shaped protrusions 41 and discontinuous linear protrusions 42. The remaining structures and functions of membrane element 100 are the same as those in the first embodiment and are not further described here.

[0067] In this embodiment, the dot-shaped protrusions 41 and the discontinuous linear protrusions 42 can be arranged as follows: Figure 6 The arrangement shown forms a dot-line matrix structure. Compared to the linear matrix of projections based on dot-shaped projections 41 in Example 1 and the linear matrix of projections based on discontinuous linear projections 42 in Example 2, this dot-line matrix structure guides the water flow path within the membrane element 100 in a more chaotic manner, further extending the water flow's residence time within the membrane element 100 and increasing water production. The different shapes of the linear matrix projections can alter the water flow path within the membrane element 100, extending the water flow path and increasing the water flow's residence time on the membrane surface.

[0068] Example 4

[0069] like Figure 9 and Figure 10 As shown, this embodiment provides a membrane element 100 having a linear matrix of protrusions on its surface. The only difference between this embodiment and the second embodiment is that the protrusions 4 are continuous linear protrusions 43. That is, the linear matrix protrusions are a linear matrix structure composed of continuous linear protrusions 43. The remaining structures and functions of the membrane element 100 are the same as those of the first embodiment and are not further described here.

[0070] In this embodiment, the continuous line protrusions 43 can be straight line protrusions, wavy line protrusions, or a mixture of the two. Compared with the linear matrix protrusions composed of discontinuous protrusions in the first and second embodiments, the linear matrix protrusions composed of the continuous line protrusions 43 guide the water flow in the membrane element 100 in a directional manner. A fixed water flow guiding path is formed between any two adjacent continuous line protrusions 43, such as Figure 9 As shown, the straight continuous line protrusion 43 is tilted to form a water flow path rotating around the membrane on the wound membrane element 100; Figure 10 As shown, the water flow path formed between the wavy, continuous linear protrusions 43 exhibits an S-shaped undulating and swirling pattern. Both the aforementioned circumferential flow path and the S-shaped undulating and swirling flow path help extend the water's residence time within the membrane element 100, increasing both water production and efficiency. The different shapes of the linear matrix protrusions can alter the water flow path within the membrane element 100, extending the flow path and increasing the water's residence time on the membrane surface.

[0071] Example 5

[0072] This embodiment provides a method for preparing a membrane element 100 based on any one of Examples 1 to 4. The composite layers of the membrane element 100 are the same as those of conventional membrane elements, with a base layer 1 in the middle, a loose support layer 2 on the outside of the base layer 1, and a thin film layer 3 on the outside of the loose support layer 2. Unlike conventional membrane elements, which are flat membranes with no surface structure, the membrane element 100 of this embodiment has a linear matrix protrusion structure on its surface. This linear matrix protrusion can be formed in a variety of ways:

[0073] The first method is to directly composite the thin film layer 3, the loose support layer 2 having protrusions 4 (or linear matrix protrusions), and the base layer 1 having protrusions 4 (or linear matrix protrusions) to form the membrane element 100;

[0074] The second method is to composite the base layer 1 and the loose support layer 2 to form an assembly, and then process the protrusions 4 (or linear matrix protrusions) on the assembly by rolling or molding; then, the assembly with the protrusions 4 (or linear matrix protrusions) is composited with the thin film layer 3 to form the membrane element 100;

[0075] The third method is to compositely process the base layer 1, the loose support layer 2 and the thin film layer 3 to form a membrane element 100 preform, and then process protrusions 4 (or linear matrix protrusions) on the membrane element 100 preform by rolling or molding to form the membrane element 100.

[0076] The preparation method of the membrane element 100 proposed in this embodiment can be to directly use a base layer 1 having linear matrix protrusions and a loose support layer 2; it can also be achieved by rolling each layer separately during production, and the base layer 1 and loose support layer 2 can be rolled and then attached to the thin film layer 3, or the three layers can be rolled together after the three layers are composited. Compared with directly spraying, printing, or depositing linear matrix protrusions on the surface of the membrane element, the attachments on the membrane surface through spraying, printing, or deposition will occupy the surface area of the membrane element, reducing the area of the membrane element. In this embodiment, the processing is performed directly on the membrane sheet without adding any additional substances. The surface area of the membrane element 100 is not affected. On the contrary, the protrusions on the membrane surface still have permeability, which increases the membrane area to a certain extent.

[0077] In actual operation, there are many different specific molding methods. This example is only used as a detailed explanation. The molding solutions obtained by adjusting its principles or processing methods are all within the protection scope of this technical solution.

[0078] Example 6

[0079] This embodiment provides a filter element, including a central tube 200 and any one of the membrane elements 100 described in Embodiments 1 to 4. The membrane element 100 is wound around the outer periphery of the central tube 200 to form a rolled laminated structure.

[0080] The filter element proposed in this embodiment uses the above-mentioned membrane element 100, which can greatly improve the water production and water production rate of the membrane element, and at the same time improve the anti-fouling and anti-clogging ability of the membrane itself.

[0081] Example 7

[0082] This embodiment provides a water purifier, including a filter element having any one of the membrane elements 100 according to the first to fourth embodiments.

[0083] The water purifier proposed in this embodiment uses the above-mentioned membrane element 100, which can greatly improve the water production and water production rate of the membrane element, and at the same time improve the anti-fouling and anti-clogging ability of the membrane itself.

[0084] In summary, the new membrane element 100 proposed in this technical solution is a membrane element with high flux, high water production rate, and resistance to fouling and clogging. By changing the diaphragm processing technology, the surface of the membrane presents a linear matrix raised structure, and the linear matrix raised structure on the surface of the diaphragm replaces the original water inlet screen and water production screen, thereby reducing the gap between the diaphragms, thereby increasing the membrane area and achieving the effect of increasing water production. At the same time, since there is no screen blocking between the diaphragms, the gap between the diaphragms is smaller, thereby increasing the water flow rate between the diaphragms, making it have a flushing effect during the water production process, reducing the time for impurities in the raw water to settle, achieving the effect of anti-fouling and clogging, and increasing the service life of the membrane.

[0085] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description. It is intended that all changes that fall within the meaning and range of equivalents of the claims be included in the present invention, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0086] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A membrane element, characterized in that: It comprises a base layer, a loose support layer and a film layer laid in sequence, wherein a side of the base layer facing the film layer and a side of the loose support layer facing away from the base layer are both provided with a plurality of water-permeable protrusions, and the protrusion height is less than the thickness of the water inlet spacer and the water production spacer; wherein the protrusions provided on the side of the base layer facing the film layer can separate two adjacent layers of the membrane elements when the membrane elements are wound around the central tube to form an axial water flow path; wherein the loose support layer and the film layer are laid from the inside to the outside on both sides of the base layer; the plurality of protrusions are provided on both sides of the base layer and on the side of any one of the loose support layers facing away from the base layer; the film layer and the surface of the loose support layer provided with the protrusions are in contact with each other; The protrusions are continuous line protrusions, and the continuous line protrusions on the base layer and the continuous line protrusions on the loose support layer are arranged in a line matrix structure; the linear continuous line protrusions are arranged obliquely; Alternatively, the protrusions are a combination of point-like protrusions and discontinuous linear protrusions, and the several protrusions on the base layer and the several protrusions on the loose support layer are arranged in a dot-line matrix structure; the protrusions include multiple groups of first discontinuous linear protrusions, multiple groups of second discontinuous linear protrusions and multiple groups of point-like protrusions, each group of the first discontinuous linear protrusions includes multiple first linear protrusions extending along the length direction of the membrane element and inclined to one side of the width direction of the membrane element, each group of the second discontinuous linear protrusions includes multiple first linear protrusions extending along the length direction of the membrane element and inclined to the other side of the width direction of the membrane element A second linear protrusion inclined on one side, each group of the point protrusions includes a plurality of point protrusions extending along the length direction of the membrane element, one point protrusion is arranged between two adjacent first linear protrusions of each group of the first discontinuous linear protrusions, and one point protrusion is arranged between two adjacent second linear protrusions of each group of the second discontinuous linear protrusions, a gap is left between each first linear protrusion and each second linear protrusion, and each first linear protrusion of each group of the first discontinuous linear protrusions and each second linear protrusion of the adjacent second discontinuous linear protrusions are staggered.

2. The membrane element according to claim 1, characterized in that The membrane element is a reverse osmosis membrane or a nanofiltration membrane.

3. The membrane element according to claim 1, characterized in that The continuous line protrusions are straight line protrusions and / or wavy line protrusions.

4. A method for preparing a membrane element according to any one of claims 1 to 3, characterized in that: include: Directly composite-processing the thin film layer, the loose support layer having the protrusions, and the base layer having the protrusions to form the membrane element; Alternatively, the base layer and the loose support layer are composite-processed to form a combination, and then the protrusions are processed on the combination; Then, the assembly with the protrusions and the thin film layer are composite-processed to form the membrane element; Alternatively, after the base layer, the loose support layer and the thin film layer are compositely processed to form a membrane element preform, the protrusions are processed on the membrane element preform to form the membrane element.

5. A filter element, characterized in that: The invention comprises a central tube and the membrane element according to any one of claims 1 to 3, wherein the membrane element is wound around the outer periphery of the central tube to form a rolled laminated structure.

6. A water purifier, comprising a filter element, characterized in that: The filter element comprises the membrane element according to any one of claims 1 to 3.

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