Hollow membrane filtering device
By designing a spiral-shaped channel formed by the inner and outer wires of the spiral-set inner and outer wires in the hollow membrane filtration device, the obstacle and shear force of the protection net to the biological fluid are reduced, and the flow of the protection net to the biological fluid in the prior art is solved. The barriers and shearing force problems improve filtration efficiency and stability of membrane wire.
Patent Information
- Application Number
- CN202323275500.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-02
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2033-12-02
AI Technical Summary
The protective net of the existing hollow membrane filtration device will hinder and shear force the flow of biological fluid, resulting in damage to the active ingredients.
Design a protective net, the inner and outer wires are arranged along the axial direction of the hollow film bundle, forming a spiral inner and outer channel, reducing obstacles to biological fluid, and forming a flat net through the interweaving of the inner and outer wires. reduces shear force.
It effectively reduces the obstacles of the protection network to the flow of biological fluid during the passage of biological fluid, reduces the damage of the active components in biological fluid by shear force, and improves the stability of the hollow film bundle, avoiding positional misalignment and turbulence.
Smart Images
Figure CN222151566U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of filtering equipment, in particular to a hollow membrane filtering device. Background Art
[0002] Biological products such as antibodies, growth factors and antibiotics used in the pharmaceutical field are obtained by culturing, inducing and expressing human, animal, plant and microbial cells through artificial intervention. However, since biological products are produced by biological cells, the product composition is complex and it is difficult to meet the use requirements of biomedicine. Therefore, it is necessary to separate and purify biological liquids containing biological macromolecules such as antibodies and viruses; the most commonly used separation and purification method is membrane separation, because membrane separation technology has high separation efficiency, low energy consumption, can be carried out at room temperature, and has a high recovery rate of biological products. Traditional filtration processes often adopt a dead-end form. Since biological macromolecules are doped with cell fragments or some sticky cell metabolites, it is easy to form scale on the membrane surface, resulting in blockage of membrane pores, thereby reducing the filtration performance of the membrane. Therefore, in order to reduce the blockage of membrane pores, tangential flow filtration has been widely used.
[0003] When a hollow membrane filtration device using tangential flow filtration is filtering biological fluid, the pressure changes and the flow of the biological fluid itself will cause the hollow membrane fibers in the hollow membrane bundle to shake. In order to protect the hollow membrane fibers, a protective net needs to be installed outside the hollow membrane bundle. However, the added protective net will hinder the flow of the biological fluid, generate shear force on the biological fluid, and destroy the effective ingredients in the biological fluid. Utility Model Content
[0004] In order to overcome the shortcomings of the protective net in the existing hollow membrane filtration device that the flow of biological liquid is hindered, the shear force on the biological liquid is generated, and the effective components in the biological liquid are destroyed, the utility model provides a hollow membrane filtration device, which reduces the obstruction of the protective net to the flow of the biological liquid, reduces the shear force on the biological liquid, and thus reduces the destruction of the effective components in the biological liquid by the shear force.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] A hollow membrane filtration device comprises a hollow membrane bundle, a hollow tube and a protective net, wherein the hollow tube comprises an inner cavity parallel to the axial direction of the hollow membrane bundle, a tube wall surrounding the inner cavity, a port and a side opening arranged on the tube wall, the hollow membrane bundle is arranged in the inner cavity, a cavity is arranged between the hollow membrane bundle and the inner wall of the inner cavity, the feed liquid in the cavity flows along the axial direction of the hollow membrane bundle, the hollow membrane bundle comprises a plurality of axially extending hollow membrane filaments, the protective net circumferentially surrounds the outside of the hollow membrane bundle and extends along the axial direction of the hollow membrane bundle, the protective net comprises a plurality of inner filaments spirally arranged along the axial direction of the hollow membrane bundle and a plurality of outer filaments spirally arranged along the axial direction of the hollow membrane bundle, the outer filaments are arranged on the outside of the inner filaments, a spiral inner channel is formed between adjacent inner filaments, a spiral outer channel is formed between adjacent outer filaments, and the inner filaments and the outer filaments are interwoven to form a mesh through which the feed liquid flows radially.
[0007] In the above technical scheme, the protective net includes inner wires and outer wires outside the inner wires which are independently arranged, wherein the mesh of the protective net is formed by interweaving the inner wires and the outer wires, and the interweaving is realized by embedding at least a part of the inner wires and the outer wires with each other, and the formed protective net surrounds the hollow membrane bundle, and the inner wires and the outer wires are independently arranged and interwoven with each other, so that the mesh surface is relatively smoother, and the membrane wires are prevented from being damaged, thereby having a binding and protective effect on the hollow membrane bundle, and at the same time, the inner wires and the outer wires of the protective net are both spirally arranged relative to the axial direction of the hollow membrane bundle and interwoven to form mesh holes, so that the inner wires and the outer wires at the mesh holes are inclined relative to the flow path of the hollow membrane bundle, and when the biological liquid shuttles between the mesh holes along the axial direction or radial direction of the hollow membrane bundle, it can flow along the inclined flow path, and has a diversion effect; at the same time, Since the inner and outer wires are arranged relative to the axial spiral of the hollow membrane bundle to form a spiral inner channel and a spiral outer channel, and the inner and outer wires are arranged in layers, the biological liquid can flow along the spiral inner channel and the spiral outer channel, and the biological liquid is not easily obstructed by the outer wires when flowing in the spiral inner channel, and the biological liquid is not easily obstructed by the inner wires when flowing in the spiral outer channel, thereby reducing the obstruction of the protective net to the flow of the biological liquid, reducing the shear force on the biological liquid, and thus reducing the damage to the effective ingredients in the biological liquid by the shear force; in addition, after the inner and outer wires of the protective net are arranged relative to the axial spiral of the hollow membrane bundle, when the hollow membrane bundle moves or deforms, the inner cylinder is also easy to move or deform synchronously with the tilt direction, avoiding damage or turbulence caused by the position misalignment between the inner cylinder and the hollow membrane bundle.
[0008] Preferably, the helix angle of the inner wire is in the range of 20°-60°, and the helix angle of the outer wire is in the range of 20°-60°.
[0009] In the above technical scheme, in the present invention, the helix angle refers to the acute angle between the tangent of the spiral line of the cylindrical protective net and the straight generatrix of the cylindrical surface passing through the tangent point; the size of the helix angle affects the inclination angle of the spiral inner channel and the spiral outer channel relative to the axial direction, as well as the number of interlacing points of the inner and outer wires. The inclination angle of the spiral inner channel and the spiral outer channel relative to the axial direction is too large, which will cause the angle area between the inner and outer channels and the axial flow of the feed liquid to be perpendicular, which is not conducive to the flow of the feed liquid, and will cause the shear force on the biological feed liquid to increase. The inclination angle of the spiral inner channel and the spiral outer channel relative to the axial direction is too small, and the length of the wire between each interlacing point is too long, which will cause the interlacing points of the inner and outer wires to be too few, so that the connection strength of the protective net and its binding effect on the hollow membrane bundle are weakened, and the protective effect of the protective net on the hollow membrane wire is reduced, causing the hollow membrane wire to shake easily. Therefore, it is necessary to control the helix angle of the inner and outer wires within a certain range, and reduce the shear force on the biological feed liquid as much as possible under the premise of satisfying the connection strength of the protective net and the binding effect on the hollow membrane bundle.
[0010] Preferably, the hand direction of the inner thread is opposite to that of the outer thread; or, the hand direction of the inner thread is the same as that of the outer thread, and the helix angle of the inner thread is greater than that of the outer thread; or, the hand direction of the inner thread is the same as that of the outer thread, and the helix angle of the inner thread is smaller than that of the outer thread.
[0011] The above three schemes can make the mesh formed by the rotation direction of the inner wire and the outer wire interweaving, while satisfying the connection strength of the protective net and the binding effect on the hollow membrane bundle, reduce the shear force on the biological liquid as much as possible.
[0012] Preferably, the distance between any two adjacent outer threads is equal and is d1, and the distance between any two adjacent inner threads is equal and is d2, d1=d2.
[0013] In the above technical solution, the mesh formed by the interweaving of the inner and outer wires is a parallelogram and the size of each mesh is the same, so that the protective net can restrain the hollow membrane bundle more evenly, and the meshes of the same size can keep the flow of the biological liquid relatively stable.
[0014] Preferably, the inner wire and the outer wire are fixed by interlacing points. The solution can fix the inner wire and the outer wire into an integrated structure, thereby increasing the binding effect of the protective net.
[0015] Preferably, the radial thickness of the protective net is H, the hole area of the mesh is S, and H / S=0.08-0.18.
[0016] In the above technical solution, the increase in the thickness of the protective net increases its corresponding mechanical strength, which will increase its protective effect on the hollow membrane filaments. However, if the thickness of the protective net is too large, the flow rate of the protective net will decrease. Increasing the hole area of the mesh can increase the flow rate of the protective net, but if the hole area is too large, the protective effect of the protective net will decrease. Therefore, it is necessary to set the radial thickness of the protective net and the hole area of the mesh within the above range to meet the protective effect of the protective net on the hollow membrane filaments and ensure the flow rate of the protective net at the same time.
[0017] Preferably, the opening ratio of the protection net is 30%-90%.
[0018] In the above technical solution, the larger the opening rate of the protective net, the greater the flow efficiency of the mesh, and the smaller the opening rate of the protective net, the better the restraint protection effect of the protective net. When the opening rate of the protective net is 30%-90%, the flow efficiency and the restraint protection effect of the mesh can be taken into account.
[0019] Preferably, the protection net is flexible so that the protection net can always fit the hollow membrane fibers when the hollow membrane fibers move radially.
[0020] In the above technical scheme, when the hollow membrane filtration device filters the biological liquid, due to the change in water pressure and the flow of the biological liquid, the hollow membrane bundle in the protective net will expand, contract and shake to a certain extent. The protective net is flexible, so that the protective net can always fit the hollow membrane filaments as the hollow membrane filaments move radially, thereby fitting, binding and protecting the hollow membrane filaments to achieve better protection effect.
[0021] Preferably, the hollow membrane bundle comprises a filtering portion and a potting portion arranged at opposite ends of the filtering portion, and the protective net comprises an embedding portion embedded in the potting portion and a protective portion arranged between the two embedding portions.
[0022] In the above technical solution, the protection part can restrain the hollow membrane filaments to prevent the hollow membrane filaments from shaking too much and affecting the life of the hollow membrane filaments; at the same time, the embedded part can fix the end of the protection net and the hollow membrane bundle as a whole.
[0023] Preferably, one end of the embedded portion away from the protecting portion is arranged in the potting portion.
[0024] In the above technical scheme, the embedded part is arranged in the potting part to fix the two ends of the protective net, increase the binding effect of the protective net, and enable the protective net to play a better binding and protective role; and the protective net can be sleeved on the outside of the hollow membrane bundle before the potting part is formed. When the potting part is formed, the embedded part can be fixed to the potting part after the potting material is solidified. There is no need to set other fixing structures, and the processing is more convenient.
[0025] In summary, the present invention includes at least one of the following beneficial technical effects:
[0026] 1. The inner wire and the outer wire are arranged relative to the axial spiral of the hollow membrane bundle to form a spiral inner channel and a spiral outer channel, and the inner wire and the outer wire are arranged in layers, the biological liquid can flow along the spiral inner channel and the spiral outer channel, the biological liquid is not easily obstructed by the outer wire when flowing in the spiral inner channel, and the biological liquid is not easily obstructed by the inner wire when flowing in the spiral outer channel, thereby reducing the obstruction of the protective net to the flow of the biological liquid, reducing the shear force on the biological liquid, and thus reducing the damage of the shear force to the effective components in the biological liquid.
[0027] 2. After the inner and outer threads of the protective net are arranged relative to the axial spiral of the hollow membrane bundle, when the hollow membrane bundle moves or deforms, the inner cylinder is also easy to move or deform synchronously with the tilt direction, avoiding damage or turbulence caused by the position misalignment between the inner cylinder and the hollow membrane bundle.
[0028] 3. The protection net is flexible, so that the protection net can always fit the hollow membrane fibers when the hollow membrane fibers move radially, thereby fitting, restraining and protecting the hollow membrane fibers to achieve better protection effect.
[0029] 4. The embedded part is arranged in the potting part to fix the two ends of the protective net, increase the binding effect of the protective net, and make the protective net play a better binding and protective role. The protective net can be sleeved on the outside of the hollow membrane bundle before the potting part is formed. When the potting part is formed, the embedded part can be fixed to the potting part after the potting material is solidified. No other fixing structure is required, and the processing is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 This is a schematic diagram of the overall structure of the utility model Figure 1 ;
[0031] Figure 2 This is a schematic diagram of the overall structure of the utility model Figure 2 ;
[0032] Figure 3 This is a schematic diagram of the structure of the protective net in the utility model. Figure 1 ;
[0033] Figure 4 It is a top view of the protective net in the utility model;
[0034] Figure 5 It is the front view of the protective net in the utility model.
[0035] In the figure: hollow membrane bundle 100, filtering part 110, potting part 120, hollow tube 200, inner cavity 201, tube wall 202, port 203, side opening 204, cavity 205, protective net 300, inner wire 301, outer wire 302, spiral inner channel 303, spiral outer channel 304, mesh 305. DETAILED DESCRIPTION
[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0037] Embodiment 1:
[0038] like Figures 1 to 5 As shown, a hollow membrane filtration device includes a hollow membrane bundle 100, a hollow tube 200 and a protective net 300, wherein the hollow tube 200 includes an inner cavity 201 parallel to the axial direction of the hollow membrane bundle 100, a tube wall 202 surrounding the inner cavity 201, a port 203 and a side opening 204 arranged on the tube wall 202, the hollow membrane bundle 100 is arranged in the inner cavity 201, a cavity 205 is arranged between the hollow membrane bundle 100 and the inner wall of the inner cavity 201, and the feed liquid in the cavity 205 flows along the axial direction of the hollow membrane bundle 100, and the hollow membrane bundle 100 includes a plurality of axially extending hollow Membrane wire, the protective net 300 circumferentially surrounds the outside of the hollow membrane bundle 100 and extends along the axial direction of the hollow membrane bundle 100, and is characterized in that the protective net 300 includes a plurality of inner wires 301 arranged along the axial spiral of the hollow membrane bundle 100 and a plurality of outer wires 302 arranged along the axial spiral of the hollow membrane bundle 100, the outer wires 302 are arranged on the outside of the inner wires 301, a spiral inner channel 303 is formed between adjacent inner wires 301, a spiral outer channel 304 is formed between adjacent outer wires 302, and the inner wires 301 and the outer wires 302 are interwoven to form a mesh 305 for radial flow of feed liquid.
[0039] In the present application, the biological liquid to be screened and graded is called the stock solution, the biological liquid that passes through the membrane wall of the hollow membrane filament is called the filtrate, and the biological liquid that is blocked by the membrane wall of the hollow membrane filament and does not pass through the membrane wall of the hollow membrane filament is called the retentate. The above-mentioned hollow membrane filtration device can adopt an internal pressure filtration mode or an external pressure filtration mode when filtering the biological liquid. When the internal pressure filtration mode is adopted, the biological liquid enters the hollow membrane filament from one end of the hollow tube 200, and the filtered stock solution is filtered through the fiber membrane wall of the filter part 110 to become the filtrate and enter the cavity 205, and flows along the cavity 205 to the side opening 204, and then flows out of the hollow membrane filtration device through the side opening 204, and the impurities filtered and retained in the hollow membrane filament can be discharged from the hollow membrane filament through the other end of the hollow membrane filament, and discharged from the hollow membrane filtration device. In some hollow membrane filtration devices, the hollow membrane filaments are open at only one end, and the other end is a non-enclosed structure. Then, the filtered stock solution enters the hollow membrane filaments from the open end, and the filtrate retained in the hollow membrane filaments can be discharged from the open end of the hollow membrane filaments by regular backwashing. When the external pressure filtration mode is adopted, the filtered stock solution enters the cavity 205 from the side opening 204, and the filtered stock solution flows along the axis to the entire cavity 205. The biological material liquid in the cavity 205 is filtered by the fiber membrane wall of the hollow membrane filament and becomes the filtrate, which enters the hollow membrane filament and flows along the axial direction of the hollow membrane filament to the outside of the hollow membrane bundle 100, and flows out of the hollow membrane filtration device. The filtrate retained in the cavity 205 can pass through the side opening 204 on another hollow tube 200. The cavity 205. In some hollow membrane filtration devices, only one side opening 204 is provided on the hollow tube 200, and the retentate retained by filtration in the cavity 205 can be discharged from the side opening 204 by regular backwashing. For ease of understanding, the following content of this application will be described in the internal pressure filtration mode.
[0040] In the above technical solution, the protective net 300 can surround the hollow membrane bundle 100, and has a binding and protective effect on the hollow membrane bundle 100. At the same time, the inner wire 301 and the outer wire 302 of the protective net 300 are both spirally arranged relative to the axial direction of the hollow membrane bundle 100 and intertwined to form a mesh 305, so that the inner wire 301 and the outer wire 302 at the mesh 305 are inclined relative to the flow path of the hollow membrane bundle 100. When the biological fluid shuttles between the meshes 305 along the axial or radial direction of the hollow membrane bundle 100, it can flow along the inclined flow path, which has a diversion effect; at the same time, because the inner wire 301 and the outer wire 302 are both spirally arranged relative to the axial direction of the hollow membrane bundle 100 to form a spiral inner channel 303 and a spiral outer channel 304, and the inner wire 301 and the outer wire 302 The layered arrangement allows the biological fluid to flow along the spiral inner channel 303 and the spiral outer channel 304. The biological fluid is not easily obstructed by the outer wire 302 when flowing in the spiral inner channel 303, and is not easily obstructed by the inner wire 301 when flowing in the spiral outer channel 304, thereby reducing the obstruction of the protective net 300 to the circulation of the biological fluid and reducing the shear force on the biological fluid, thereby reducing the damage of the shear force to the effective ingredients in the biological fluid. In addition, after the inner wire 301 and the outer wire 302 of the protective net 300 are arranged in an axial spiral relative to the hollow membrane bundle 100, when the hollow membrane bundle 100 moves or deforms, the inner cylinder is also easily moved or deformed synchronously with the tilt direction, thereby avoiding damage or turbulence caused by the position misalignment between the inner cylinder and the hollow membrane bundle 100.
[0041] Specifically, the protective net 300 is flexible so that the protective net 300 can always fit the hollow membrane filaments when the hollow membrane filaments move radially. When the hollow membrane filtration device is filtering the biological liquid, due to the change in water pressure and the flow of the biological liquid, the hollow membrane bundle 100 in the protective net 300 will expand, shrink and shake to a certain extent. The protective net 300 is flexible, so that the protective net 300 can always fit the hollow membrane filaments when the hollow membrane filaments move radially, and the hollow membrane filaments are fitted, bound and protected to achieve a better protection effect.
[0042] Preferably, the hollow membrane bundle 100 includes a filter portion 110 and a potting portion 120 disposed at opposite ends of the filter portion 110, and the protective net 300 includes an embedded portion embedded in the potting portion 120 and a protective portion disposed between the two embedded portions, and one end of the embedded portion away from the protective portion is disposed in the potting portion 120. In the above technical solution, the protective portion can restrain the hollow membrane filaments to prevent the hollow membrane filaments from shaking too much, thereby affecting the life of the hollow membrane filaments. The embedded portion can fix the end of the protective net 300 and the hollow membrane bundle 100 as a whole. The embedded portion is disposed in the potting portion 120 to fix the two ends of the protective net 300, increase the restraining effect of the protective net 300, and enable the protective net 300 to play a better restraining and protective role. Moreover, the protective net 300 can be sleeved on the outside of the hollow membrane bundle before the potting part 120 is formed. When the potting part 120 is formed, the embedded part can be fixed to the potting part 120 after the potting material is solidified. There is no need to set up other fixing structures, and the processing is more convenient.
[0043] Specifically, the helical angle of the inner wire 301 is in the range of 20°-60°, and the helical angle of the outer wire 302 is in the range of 20°-60°. In the above technical solution, the size of the helical angle affects the inclination angle of the spiral inner channel 303 and the spiral outer channel 304 relative to the axial direction, as well as the number of interlacing points of the inner wire 301 and the outer wire 302. If the inclination angle of the spiral inner channel 303 and the spiral outer channel 304 relative to the axial direction is too large, it is not conducive to the flow, and will cause the shear force on the biological liquid to increase. If the inclination angle of the spiral inner channel 303 and the spiral outer channel 304 relative to the axial direction is too small, it will lead to too few interlacing points of the inner wire 301 and the outer wire 302, which will weaken the connection strength of the protective net 300 and its binding effect on the hollow membrane bundle 100, resulting in a decrease in its protective effect on the hollow membrane bundle 100. Therefore, it is necessary to control the helical angles of the inner wire 301 and the outer wire 302 within a certain range, and to reduce the shear force on the biological fluid as much as possible while satisfying the connection strength of the protective net 300 and the binding effect on the hollow membrane bundle 100 therein.
[0044] Preferably, the rotation direction of the inner wire 301 is opposite to that of the outer wire 302, and the inner wire 301 and the outer wire 302 are fixed by an interlacing point. The distance between any two adjacent outer wires 302 is equal and the distance is d1, and the distance between any two adjacent inner wires 301 is equal and the distance is d2, d1=d2. The above technical scheme makes the rotation direction of the inner wire 301 interweave with the outer wire 302 to form a mesh 305, and the inner wire 301 and the outer wire 302 are fixed into an integral structure, increasing the binding effect of the protective net 300, and at the same time, the mesh 305 formed by the interweaving of the inner wire 301 and the outer wire 302 is a parallelogram and the size of each mesh 305 is the same, so that the protective net 300 can restrain the hollow membrane bundle 100 more evenly, and the mesh 305 of the same size can keep the flow of the biological liquid relatively stable.
[0045] Preferably, the radial thickness of the protective net 300 is H, the hole area of the mesh 305 is S, and H / S=0.03-0.18. The opening rate of the protective net 300 is 30%-90%; wherein the opening rate refers to the percentage of the total area of the mesh 305 to the total area of the protective net, and the opening rate can be calculated according to GB / T 17492-2019. The larger the opening rate of the protective net 300, the greater the circulation efficiency of the mesh 305, and the smaller the opening rate of the protective net 300, the better the restraint effect of the protective net 300; therefore, when the opening rate of the protective net 300 is 30%-90%, the circulation efficiency and restraint effect of the mesh 305 can be taken into account.
[0046] It is understandable that in another embodiment, the inner thread 301 has the same hand direction as the outer thread 302, and the helix angle of the inner thread 301 is greater than the helix angle of the outer thread 302. The above solution enables the hand direction of the inner thread 301 to be interwoven with the outer thread 302 to form the mesh 305.
[0047] It can be understood that in another embodiment, the inner thread 301 has the same hand direction as the outer thread 302, and the helix angle of the inner thread 301 is smaller than the helix angle of the outer thread 302. The above scheme enables the hand direction of the inner thread 301 to be interwoven with the outer thread 302 to form a mesh 305, and the shear force on the biological fluid can be reduced as much as possible under the premise of satisfying the connection strength of the protective net 300 and the binding effect on the hollow membrane bundle 100 therein.
Claims
1. A hollow membrane filtration device, comprising a hollow membrane bundle, a hollow tube and a protective net, wherein the hollow tube comprises an inner cavity parallel to the axial direction of the hollow membrane bundle, a tube wall surrounding the inner cavity, a port and a side opening arranged on the tube wall, the hollow membrane bundle is arranged in the inner cavity, a cavity is arranged between the hollow membrane bundle and the inner wall of the inner cavity, and the feed liquid in the cavity flows along the axial direction of the hollow membrane bundle, the hollow membrane bundle comprises a plurality of axially extending hollow membrane filaments, the protective net circumferentially surrounds the outer side of the hollow membrane bundle and extends along the axial direction of the hollow membrane bundle, and is characterized in that: The protective net includes a plurality of inner wires arranged in an axial spiral along the hollow membrane bundle and a plurality of outer wires arranged in an axial spiral along the hollow membrane bundle. The outer wires are arranged on the outside of the inner wires, and a spiral inner channel is formed between adjacent inner wires, and a spiral outer channel is formed between adjacent outer wires. The inner wires and the outer wires are interwoven to form mesh holes for radial flow of feed liquid.
2. A hollow membrane filtration device according to claim 1, characterized in that: The helix angle of the inner wire is in the range of 20°-60°, and the helix angle of the outer wire is in the range of 20°-60°.
3. A hollow membrane filtration device according to claim 1, characterized in that: The hand direction of the inner thread is opposite to that of the outer thread; or, the hand direction of the inner thread is the same as that of the outer thread, and the helix angle of the inner thread is greater than that of the outer thread; or, the hand direction of the inner thread is the same as that of the outer thread, and the helix angle of the inner thread is less than that of the outer thread.
4. A hollow membrane filtration device according to claim 1, characterized in that: The distance between any two adjacent outer wires is equal and the distance is d1, and the distance between any two adjacent inner wires is equal and the distance is d2, d1=d2.
5. A hollow membrane filtration device according to claim 1, characterized in that: The inner wire and the outer wire are fixed via interlacing points.
6. A hollow membrane filtration device according to claim 1, characterized in that: The opening rate of the protection net is 30%-90%.
7. A hollow membrane filtration device according to claim 1, characterized in that: The protection net is flexible so that the protection net can always fit the hollow membrane fibers when the hollow membrane fibers move radially.
8. A hollow membrane filtration device according to claim 1, characterized in that: The hollow membrane bundle comprises a filtering part and a potting part arranged at two opposite ends of the filtering part, and the protective net comprises an embedding part embedded in the potting part and a protective part arranged between the two embedding parts.
9. A hollow membrane filtration device according to claim 8, characterized in that: One end of the embedded portion away from the protecting portion is arranged in the potting portion.