High-pressure alkali-resistant spiral wound membrane module

Abstract

This utility model relates to a high-pressure alkali-resistant spiral wound membrane module, comprising: a central tube, a winding assembly, end caps, and fiberglass. The central tube has a through hole communicating with its interior. The winding assembly is wound around the outer circumference of the central tube with its axis as the axis. The winding assembly includes a membrane bag and an inlet screen stacked and connected in the thickness direction. The interior of the membrane bag communicates with the through hole. The membrane bag includes a membrane sheet and a product screen. The membrane sheet is folded and includes a first part and a second part arranged opposite to each other. The first part is connected to the second part. The product screen is located between the first part and the second part and is connected to the first part and / or the second part. Two end caps are provided, each sleeved on both ends of the central tube and covering the axial ends of the winding assembly. The end caps have water passage holes that cooperate with the inlet screen. Fiberglass is wound around the outside of the winding assembly.

Description

Technical Field

[0001] This utility model relates to the field of functional spiral wound membrane modules, and more specifically, to a high-pressure alkali-resistant spiral wound membrane module. Background Technology

[0002] Alkali-resistant spiral wound membrane modules are spiral wound membrane elements made of alkali-resistant materials. They are used to treat industrial wastewater containing alkaline substances, raising the alkali concentration in the wastewater to the required level for the process. This allows the wastewater to be directly reused in relevant processes, avoiding the significant waste of raw materials caused by direct discharge of alkaline wastewater and significantly reducing the procurement cost of fresh alkali. Specifically, large amounts of alkaline wastewater are generated in industries such as hemicellulose, chemical pharmaceuticals, food processing, mining, metallurgy, and battery energy. When alkali-resistant spiral wound membrane modules are used in these industries, they need to be operated under different pressure conditions.

[0003] Currently, the ideal operating pressure for alkali-resistant spiral wound membrane modules mainly used in the market is around 15-25 bar, which can ensure stable operation in the semi-fiber industry where alkali recovery pressure requirements are not high. However, when these alkali-resistant spiral wound membrane modules are used in other industries with operating pressures above 30 bar, their lifespan will be greatly shortened. Especially in scenarios with operating pressures of 40-50 bar, the lifespan of alkali-resistant spiral wound membrane modules is short, requiring frequent replacement, which increases the cost pressure on enterprises.

[0004] Therefore, how to develop an alkali-resistant spiral wound membrane module that can operate stably for a long time in high-pressure environments has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0005] The purpose of this invention is to provide a high-pressure alkali-resistant spiral wound membrane module that can operate stably for a long time in high-pressure environments.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0007] This utility model provides a high-pressure alkali-resistant spiral wound membrane module, comprising: a central tube with a through hole communicating with the interior of the central tube; a winding assembly wound around the outer periphery of the central tube with the axis of the central tube as the axis, the winding assembly including a membrane bag and an inlet screen stacked and connected in the thickness direction, the interior of the membrane bag communicating with the through hole, the membrane bag including a membrane sheet and a product screen, the membrane sheet being folded and including a first part and a second part disposed opposite to each other, the first part being connected to the second part, the product screen being located between the first part and the second part and connected to the first part and / or the second part; two end caps, the two end caps respectively sleeved on both ends of the central tube and respectively covering the two ends of the winding assembly located in the axial direction, the end caps having water passage holes that cooperate with the inlet screen; and fiberglass wound around the winding assembly.

[0008] In some embodiments of this application, the water production net is made of PP, with a radial stiffness of 180-220, a weft stiffness of 130-170, a warp and weft density of 60+50 or more, a warp and weft elongation of 1.3-1.7, and a thickness of 14-16 mil.

[0009] In some embodiments of this application, the radial stiffness of the water production network is 200, the latitudinal stiffness is 150, the warp and weft density is above 65+55, and the warp and weft elongation rate is 1.5.

[0010] In some embodiments of this application, two adhesive lines are formed between the first part and the second part and are bonded together with adhesive, and the two adhesive lines are arranged at intervals along the axial direction of the central tube. The water production mesh is located between the two adhesive lines and is bonded to the first part and / or the second part respectively by adhesive. The bonding points of the water production mesh are located at both ends of the adhesive lines and extend from one adhesive line to the other adhesive line.

[0011] In some embodiments of this application, the number of membrane bags is several, and the several membrane bags are arranged sequentially in the thickness direction of the winding assembly, and a water inlet net is provided between each pair of adjacent membrane bags; the water inlet net is bonded to the first part of the membrane sheet of one of the membrane bags and / or the second part of the membrane sheet of another membrane bag by adhesive, and the bonding points of the water inlet net are located on both sides of the central tube in the axial direction and extend in the circumferential direction of the central tube.

[0012] In some embodiments of this application, a snap-fit ​​structure is formed between the end cap and the central tube. The snap-fit ​​structure includes a matching slot and a snap block, and the slot and the snap block are bonded together with adhesive.

[0013] In some embodiments of this application, the slot is formed on the outer peripheral wall of the central tube, the slot is arranged around the outer periphery of the central tube, and the depth of the slot gradually decreases from the side of the central tube away from the winding assembly to the side closer to the winding assembly; the block is protruding on the inner peripheral wall of the end cap, the block is arranged around the inner periphery of the end cap, the shape of the block is adapted to the slot, and the thickness of the block gradually decreases from the side of the end cap away from the winding assembly to the side closer to the winding assembly.

[0014] In some embodiments of this application, the action of winding the winding assembly includes a winding action and a secondary pressing action.

[0015] In some embodiments of this application, the membrane is an alkali-resistant nanofiltration membrane, the membrane is made of PP material with a molecular weight of 100-1000 kDa and an elastic modulus of 0.8-3.0 GPa.

[0016] In some embodiments of this application, the thickness of the inlet mesh is 34mil-65mil.

[0017] As can be seen from the above technical solution, the embodiments of this utility model have at least the following advantages and positive effects: In this embodiment of the high-pressure alkali-resistant spiral wound membrane module, raw water enters the winding module through a water passage on one end cap and flows along the inlet water network to act evenly on the surface of the membrane. During this process, the membrane is used to prevent most alkali ions and other large molecular impurities from passing through, thereby separating the raw water into concentrated water that does not permeate the membrane and permeate that enters the membrane bag. Specifically, the concentrated water is discharged from a water passage on the other end cap, while the permeate flows along the wound permeate network and eventually flows into the central tube, thus completing the alkali recovery.

[0018] Because there are connections between the membrane bag and the inlet water network, between the first and second parts of the membrane sheet, and between the product water network and the membrane sheet, the various components in the winding assembly can support each other, thus giving the winding assembly itself a certain degree of structural stability and reliability. Furthermore, the two end caps covering the axial ends of the winding assembly restrict movement and reduce the possibility of it loosening under high-pressure impact, thereby ensuring the structural integrity of the spiral wound membrane assembly under high-pressure environments. Moreover, fiberglass has excellent properties such as high strength, high modulus, and corrosion resistance; wrapping fiberglass around the winding assembly significantly enhances the overall structural strength of the spiral wound membrane assembly, enabling it to withstand higher pressures. Therefore, the high-pressure alkali-resistant spiral wound membrane assembly of this embodiment can operate stably for a long time in high-pressure environments. Attached Figure Description

[0019] The various objectives, features, and advantages of this invention will become more apparent from the following detailed description of preferred embodiments in conjunction with the accompanying drawings. The drawings are merely illustrative illustrations of the invention and are not necessarily drawn to scale. In the drawings, the same reference numerals always denote the same or similar parts. Wherein: Figure 1 This is a schematic diagram of a high-pressure alkali-resistant spiral wound membrane assembly according to an exemplary embodiment.

[0020] Figure 2 yes Figure 1 A sectional view.

[0021] Figure 3 yes Figure 2 A schematic diagram of its decomposed structure.

[0022] Figure 4 yes Figure 2 A schematic diagram of the exploded structure of the membrane bag.

[0023] The annotations in the attached figures are explained as follows: 1. Central tube; 11. Slot; 12. Through hole; 2. Winding assembly; 21. Membrane bag; 211. Membrane sheet; 2111. First part; 2112. Second part; 212. Product water mesh; 22. Inlet water mesh; 23. Adhesive thread; 3. End cap; 31. Water passage hole; 32. Locking block; 33. Deep groove edging structure; 4. Fiberglass. Detailed Implementation

[0024] Although the present invention can be readily embodied in various forms, only some specific embodiments are shown in the accompanying drawings and will be described in detail in this specification. It is understood that this specification should be regarded as an exemplary illustration of the principles of the present invention and is not intended to limit the present invention to what is described herein.

[0025] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present invention, and does not imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0026] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various elements of this invention are relative rather than absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the descriptions of the positions of these elements change, these directional indications also change accordingly.

[0027] Please see Figure 1 and Figure 2 The high-pressure alkali-resistant spiral wound membrane module provided in one embodiment of this utility model mainly includes a central tube 1, a winding assembly 2, an end cap 3, and a fiberglass 4. The central tube 1 has a through hole 12, which communicates with the interior of the central tube 1. The winding assembly 2 is wound around the outer periphery of the central tube 1 with the axis of the central tube 1 as the axis. The winding assembly 2 includes a membrane bag 21 and an inlet water net 22 that are stacked and connected in the thickness direction. The interior of the membrane bag 21 communicates with the through hole 12. The membrane bag 21 includes a membrane sheet 211 and a product water net 212. The membrane sheet 211 is folded and includes a first part 2111 and a second part 2112 that are arranged opposite to each other. The first part 2111 and the second part 2112 are connected. The product water net 212 is located between the first part 2111 and the second part 2112 and is connected to the first part 2111 and the second part 2112 respectively. Two end caps 3 are provided. The two end caps 3 are respectively sleeved on both ends of the central tube 1 and respectively cover the two ends of the winding assembly 2 located in the axial direction. The end caps 3 are provided with water passage holes 31 that cooperate with the water inlet net 22. Fiberglass 4 is wound around the winding assembly 2.

[0028] In this embodiment of the high-pressure alkali-resistant spiral wound membrane module, raw water enters the winding assembly 2 from a water passage 31 on one end cap 3 and flows along the water inlet mesh 22 to act evenly on the surface of the membrane sheet 211. During this process, the membrane sheet 211 is used to prevent most alkali ions and other large molecular impurities from passing through, so as to separate the raw water into concentrated water that does not permeate through the membrane sheet 211 and permeate that permeates through the membrane sheet 211 and enters the membrane bag 21. Specifically, the concentrated water is discharged from the water passage 31 on the other end cap 3, while the permeate flows along the wound product water mesh 212 and finally flows into the interior of the central tube 1, thereby completing the alkali recovery.

[0029] Because there are connections between the membrane bag 21 and the inlet water network 22, between the first part 2111 and the second part 2112 of the membrane sheet 211, and between the product water network 212 and the membrane sheet 211, the various components in the winding assembly 2 can support each other, thus giving the winding assembly 2 itself a certain degree of structural stability and reliability. Furthermore, the two end caps 3 respectively cover the two ends of the winding assembly 2 located in the axial direction, which can restrict the movement of the winding assembly 2 and reduce the possibility of the winding assembly 2 loosening under high pressure impact, thereby ensuring the structural integrity of the spiral wound membrane assembly under high pressure environment. Furthermore, the fiberglass 4 has excellent properties such as high strength, high modulus, and corrosion resistance. Wrapping the winding assembly 2 with fiberglass 4 can significantly enhance the overall structural strength of the spiral wound membrane assembly, enabling it to withstand higher pressures. Therefore, the high-pressure alkali-resistant spiral wound membrane assembly of this embodiment can operate stably for a long time in high-pressure environments.

[0030] In a specific embodiment, the water production net 212 is made of PP, with a radial stiffness of 180-220, a weft stiffness of 130-170, a warp and weft density of 60+50 or more, a warp and weft elongation of 1.3-1.7, and a thickness of 14-16mil.

[0031] In this embodiment, the radial stiffness of the water production network 212 is 200, the latitudinal stiffness is 150, the warp and weft density is above 65+55, and the warp and weft elongation rate is 1.5.

[0032] Specifically, the high radial and latitudinal stiffness of the water production net 212 ensures that it maintains a relatively stable structure in different directions. The high warp and weft density enhances the overall strength and stability of the water production net 212 and provides better support for the diaphragm 211. The appropriate elongation gives the water production net 212 a certain elastic deformation capacity when subjected to high pressure, which can buffer some of the pressure. The appropriate thickness ensures that the water production net 212 has a certain strength without increasing the resistance to water flow due to excessive thickness. Thus, the various parameters of the water production net 212 give it good stability and reliability under high pressure.

[0033] It should be noted that conventional alkali-resistant spiral wound membrane modules use ordinary PP permeate mesh 212. PP material itself is relatively soft, and once the pressure rises above 30 bar, under the frequent flushing action of feed water at a certain alkali pressure and temperature, end face deformation will occur, further stretching and deforming the permeate mesh 212, thereby damaging the membrane 211 and causing a serious decrease in the overall efficiency and performance of the spiral wound membrane module. Therefore, the above embodiments provide specific indicators of a specially made PP permeate mesh 212 to illustrate that using it to replace the conventional PP permeate mesh 212 has a stronger high-pressure resistance.

[0034] Please see Figure 4 , Figure 4 The centrally located dashed line represents the fold line of the diaphragm 211, while the other dashed lines represent the adhesive traces for bonding the water production mesh 212. In a specific embodiment, two adhesive lines 23 are formed between the first part 2111 and the second part 2112, and are bonded together by adhesive. The two adhesive lines 23 are spaced apart along the axial direction of the central tube 1. The water production mesh 212 is located between the two adhesive lines 23 and is bonded to the first part 2111 and / or the second part 2112 by adhesive. The bonding points of the water production mesh 212 are located at both ends of the adhesive lines 23 and extend from one adhesive line 23 to the other.

[0035] The first part 2111 and the second part 2112, as well as the permeate mesh 212 and the membrane 211, are connected by adhesive bonding, which features reliable connection, convenient operation, and simple structure. Specifically, the arrangement of the adhesive joints of the permeate mesh 212 reduces the possibility of end-face deformation of the permeate mesh 212 under the flushing of the permeate, thereby effectively preventing the permeate mesh 212 from being stretched and deformed, ensuring the structural stability of the membrane bag 21, and enabling the membrane bag 21 structure to be used in high-pressure scenarios.

[0036] Please see Figure 2 and Figure 3 , Figure 3 The dotted lines in the figure represent the adhesive traces for bonding the water inlet mesh 22. In a specific embodiment, there are several membrane bags 21 arranged sequentially in the thickness direction of the winding assembly 2, and a water inlet mesh 22 is provided between each pair of adjacent membrane bags 21. The water inlet mesh 22 is bonded to the first part 2111 of the membrane sheet 211 of one membrane bag 21 and / or the second part 2112 of the membrane sheet 211 of another membrane bag 21 by adhesive. The bonding points of the water inlet mesh 22 are located on both sides of the central tube 1 in the axial direction and extend in the circumferential direction of the central tube 1.

[0037] Several membrane bags 21 are arranged sequentially along the thickness direction, greatly increasing the effective filtration area of ​​the membrane module and improving the treatment efficiency of alkali recovery. Furthermore, each pair of adjacent membrane bags 21 is connected by an inlet screen 22, ensuring that each membrane bag 21 can fully contact the raw water, thus improving the utilization rate of the membrane bags 21 and further enhancing the treatment efficiency of alkali recovery. Adhesive bonding forms a strong connection between the inlet screen 22 and the membrane bags 21, preventing relative displacement or detachment, thereby further ensuring the stability of the winding assembly 2. Specifically, the arrangement of the adhesive joints of the inlet screen 22 reduces the possibility of end-face deformation under the scouring of raw water, effectively preventing the inlet screen 22 from being stretched and deformed, thereby improving the overall structural stability and reliability of the winding assembly 2.

[0038] Please see Figure 2 and Figure 3 In a specific embodiment, a snap-fit ​​structure is formed between the end cap 3 and the central tube 1. The snap-fit ​​mechanism includes a matching slot 11 and a locking block 32, which are bonded together with adhesive. The engagement between the slot 11 and the locking block 32 increases the contact area between the end cap 3 and the central tube 1. The combination of the slot 11 and the locking block 32 and the adhesive bonding enhances the connection stability and reliability between the end cap 3 and the central tube 1.

[0039] It is conceivable that a snap-fit ​​structure is formed between the end cap 3 and the central tube 1. The snap-fit ​​mechanism includes a snap-fit ​​groove 11 and a snap-fit ​​block 32. The snap-fit ​​groove 11 can be located on the central tube 1 and the snap-fit ​​block 32 can be located on the end cap 3, or the snap-fit ​​groove 11 can be located on the end cap 3 and the snap-fit ​​block 32 can be located on the central tube 1.

[0040] In a specific embodiment, a slot 11 is formed on the outer peripheral wall of the central tube 1, and the slot 11 is arranged around the outer periphery of the central tube 1. The depth of the slot 11 gradually decreases from the side of the central tube 1 away from the winding assembly 2 to the side closer to the winding assembly 2. A locking block 32 is protruding on the inner peripheral wall of the end cap 3, and the locking block 32 is arranged around the inner periphery of the end cap 3. The shape of the locking block 32 is adapted to the slot 11, and the thickness of the locking block 32 gradually decreases from the side of the end cap 3 away from the winding assembly 2 to the side closer to the winding assembly 2.

[0041] During installation, align the thinner end of the locking block 32 with the end of the central tube 1, and push the end cap 3 inward. The action of pushing the end cap 3 inward causes the thinner part of the locking block 32 to align with the deeper part of the slot 11. Continue pushing the end cap 3 inward until the locking block 32 is fully aligned with the slot 11. At this time, the locking block 32 falls into the slot 11 and is engaged with the locking block 32. The part of the central tube 1 located on both sides of the slot 11 in the axial direction forms a step that restricts the locking block 32 from leaving the slot 11, thereby further improving the stability and reliability of the connection.

[0042] Please see Figure 1 In the above embodiments, the outer peripheral wall of the end cap 3 is provided with a deep groove edging structure 33 arranged around its outer periphery, thereby improving the structural stability of the end cap 3 structure.

[0043] In a specific embodiment, the winding assembly 2's operation includes a winding action and a secondary tightening action. The secondary tightening action is performed after the winding action, which can eliminate the minute gaps existing between the winding assembly 2 and the central tube 1, as well as inside the winding assembly 2, thereby enhancing the tightness of the spiral wound film assembly and improving the overall structural stability.

[0044] In a specific embodiment, membrane 211 is an alkali-resistant nanofiltration membrane 211, made of PP material with a molecular weight of 100-1000 kDa and an elastic modulus of 0.8-3.0 GPa. The molecular weight cutoff of membrane 211 is 100-1000 kDa, specifically 100 kDa, 150 kDa, 200 kDa, 250 kDa, 500 kDa, 750 kDa, 1000 kDa, or any value between them. The elastic modulus is 0.8-3 GPa, specifically 0.8 GPa, 0.9 GPa, 1.0 GPa, 1.5 GPa, 2.0 GPa, 3.0 GPa, or any value between them.

[0045] In a specific embodiment, the thickness of the inlet mesh 22 is 34mil-65mil. Specifically, it can be 34mil, 35mil, 40mil, 50mil, 60mil, 65mil, or any value between them.

[0046] In the above embodiments, the central tube 1 is a thickened pressure-resistant type, the wall thickness of the central tube 1 is 5-10mm, the through hole 12 is circular, and its diameter is 2.8-3.5mm. In the preferred embodiment, the wall thickness of the central tube 1 is 6.6mm, and the diameter of the through hole 12 is 3.2mm.

[0047] In the above embodiments, the fiberglass 4 is formed by wrapping fiberglass and adhesive around the winding assembly 2.

[0048] To verify that the high-pressure alkali-resistant spiral wound membrane module of this invention can operate stably for a long time in high-pressure environments, two sets of comparative embodiments are provided below. Stability tests under different operating pressure conditions are conducted to verify its pressure resistance stability. The specific details are as follows: Example 1: This embodiment of the high-pressure alkali-resistant spiral wound membrane module includes a total of 18 membrane bags 21. The membrane sheets 211 are alkali-resistant nanofiltration membrane sheets 211 with a thickness of 0.2-0.25 mm. The permeate mesh 212 is made of PP permeate mesh 212 with a thickness of 12-14 mil. The feed mesh 22 is made of PP material with a thickness of 34 mil, and is obtained by rolling through the following steps: S1. Place the alkali-resistant nanofiltration membrane 211 on the membrane 211 cutting machine and cut it into membrane 211 with a length of 1900-1960mm. Fold the cut alkali-resistant nanofiltration membrane 211 in half with the non-woven fabric side facing each other. At the same time, apply glue to the inside of the membrane 211 adhesive line 23. Then place a PP water production net 212 with a width of 950-980mm in the middle to obtain a membrane bag 21.

[0049] S2. Insert a PP water inlet mesh 22 between the membrane bags 21, and then use epoxy resin glue to wrap and bond all the membrane bags 21 to the PSU / PP central tube 1.

[0050] S3. Install PP end caps 3 on both ends of the polysulfone antibacterial central tube 1 and wrap it with fiberglass 4 to obtain a spiral wound membrane assembly.

[0051] Example 2: This embodiment of the high-pressure alkali-resistant spiral wound membrane module includes a total of 15 membrane bags 21. The membrane sheets 211 are alkali-resistant nanofiltration membrane sheets 211 with a thickness of 0.2-0.25 mm. The permeate mesh 212 is made of PP permeate mesh 212 with a thickness of 12-14 mil. The flow guide grid is made of PP material with a thickness of 46 mil, and is obtained by rolling through the following steps: S1. Place the alkali-resistant nanofiltration membrane 211 on the membrane 211 cutting machine and cut it into membrane 211 with a length of 1900-1960mm. Fold the cut alkali-resistant nanofiltration membrane 211 in half with the non-woven fabric side facing each other. At the same time, apply glue to the inside of the membrane 211 adhesive line 23. Then place a PP water production net 212 with a width of 950-980mm in the middle to obtain a membrane bag 21.

[0052] S2. Insert a PP water inlet mesh 22 between the membrane bags 21, and then use epoxy resin glue to wrap and bond all the membrane bags 21 to the PSU / PP central tube 1.

[0053] S3. Install PP end caps 3 on both ends of the polysulfone antibacterial central tube 1 and wrap it with fiberglass 4 to obtain a spiral wound membrane assembly.

[0054] Test example: In this test example, the magnesium sulfate test method in the national standard document GB / T 34242-2017 "Test Methods for Nanofiltration Membranes" was used, which requires a magnesium sulfate test solution of 2000±20 mg / L, a pressure of 10-60, a pH value of 7.5±0.5, a recovery rate of 8±1%, and a desalination rate (MgSO4) of 98.5% or higher. The results are shown in Table 1.

[0055] Table 1. Performance of High-Pressure Alkali-Resistant Spiral Wound Membrane Modules

[0056] The test results show that when the high-pressure alkali-resistant spiral wound membrane modules provided in Examples 1 and 2 are used to treat magnesium sulfate solution, the high-pressure alkali-resistant spiral wound membrane modules in the two examples show no deformation after running for 0.5 hours in an environment with an operating pressure of 15-30 bar, no deformation and slight deformation after running for 48 hours in an environment with an operating pressure of 40 bar and 50 bar, respectively. After running for one month in an environment with an operating pressure of 60 bar, they can continue to operate stably with only slight deformation. Therefore, the test results show that the high-pressure alkali-resistant spiral wound membrane module of this utility model can operate stably for a long time in scenarios with high operating pressure.

[0057] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A high-pressure alkali-resistant spiral wound membrane module, characterized in that, include: The central tube has a through hole that connects to the interior of the central tube. A winding assembly is wound around the outer periphery of the central tube with the axis of the central tube as the axis. The winding assembly includes a membrane bag and an inlet water net stacked and connected in the thickness direction. The interior of the membrane bag communicates with the through hole. The membrane bag includes a membrane sheet and a product water net. The membrane sheet is folded and includes a first part and a second part disposed opposite to each other. The first part is connected to the second part. The product water net is located between the first part and the second part and is connected to the first part and / or the second part. Two end caps are provided, which are respectively fitted onto the two ends of the central tube and respectively cover the two ends of the winding assembly located in the axial direction. The end caps are provided with water passage holes that cooperate with the water inlet screen. Fiberglass is wound around the outside of the winding assembly.

2. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, The water production net is made of PP, with a radial stiffness of 180-220, a weft stiffness of 130-170, a warp and weft density of 60+50 or more, a warp and weft elongation of 1.3-1.7, and a thickness of 14-16mil.

3. The high-pressure alkali-resistant spiral wound membrane module according to claim 2, characterized in that, The radial stiffness of the water production network is 200, the latitudinal stiffness is 150, the warp and weft density is above 65+55, and the warp and weft extension rate is 1.

5.

4. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, Two adhesive lines are formed between the first part and the second part and are bonded together with adhesive, and the two adhesive lines are arranged at intervals along the axial direction of the central tube. The water production mesh is located between the two adhesive lines and is bonded to the first part and / or the second part respectively by adhesive. The bonding points of the water production mesh are located at both ends of the adhesive lines and extend from one adhesive line to the other adhesive line.

5. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, The number of membrane bags is several, and the several membrane bags are arranged sequentially in the thickness direction of the winding assembly, and the water inlet net is provided between each pair of adjacent membrane bags in each group; The inlet mesh is bonded to a first portion of the membrane sheet of one of the membrane bags and / or a second portion of the membrane sheet of the other membrane bag by adhesive. The bonding points of the inlet mesh are located on both sides of the central tube in the axial direction and extend in the circumferential direction of the central tube.

6. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, A snap-fit ​​structure is formed between the end cap and the central tube. The snap-fit ​​structure includes a matching slot and a snap block, and the slot and the snap block are bonded together with adhesive.

7. The high-pressure alkali-resistant spiral wound membrane module according to claim 6, characterized in that, The slot is formed on the outer peripheral wall of the central tube. The slot is arranged around the outer periphery of the central tube. The depth of the slot gradually decreases from the side of the central tube away from the winding assembly to the side closer to the winding assembly. The end cap has a protruding locking block on its inner peripheral wall. The locking block is arranged around the inner periphery of the end cap. The shape of the locking block is adapted to the locking groove, and the thickness of the locking block gradually decreases from the side of the end cap away from the winding assembly to the side closer to the winding assembly.

8. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, The action of winding the winding assembly includes a winding action and a secondary clamping action.

9. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, The membrane is an alkali-resistant nanofiltration membrane made of PP material with a molecular weight of 100-1000 kDa and an elastic modulus of 0.8-3.0 GPa.

10. The high-pressure alkali-resistant spiral wound membrane module according to claim 1, characterized in that, The thickness of the inlet mesh is 34mil-65mil.

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