A spiral reverse osmosis membrane element and a preparation process thereof

Abstract

The application relates to a spiral reverse osmosis membrane element and a preparation process thereof, and relates to the technical field of water treatment and membrane separation. The spiral guide rib with a trapezoidal section is integrally formed on a water inlet screen of the membrane element, the rib is in abutment with a membrane sheet in a winding state to form a three-dimensional spiral flow path, and a toughening and reinforcing glue is punctiformly arranged at an interlayer interface. The preparation process comprises the steps of membrane bag preparation, screen hot-pressing forming, winding and synchronous following glue dispensing and curing. A three-axis linear module is matched with an intermittent glue coating mechanism, precise following and lifting avoidance of a point coating head to a variable-diameter membrane roll are realized through a cam disc group driving structure, dynamic glue injection is realized in winding, and synchronous local heating and shaping are realized. The application improves the anti-pollution performance and structural stability of the membrane element, solves the winding glue dispensing interference problem, and improves the production efficiency and product yield.

Description

Technical Field

[0001] This application relates to the technical field of water treatment and membrane separation, and in particular to a spiral reverse osmosis membrane element and its preparation process. Background Technology

[0002] Spiral reverse osmosis membrane elements are the core separation units of reverse osmosis water treatment systems. Their basic structure typically includes a central product water pipe, a membrane bag wound around the outer periphery of the central product water pipe, and a feed water separator. The separation performance and service life of reverse osmosis membrane elements are closely related to their internal flow channel structure design, interlayer bonding strength, and manufacturing process level.

[0003] Currently, Chinese patent application number CN201921883577.6 discloses a spiral reverse osmosis membrane element, which includes a reverse osmosis membrane element, a sealing ring fixedly connected to the left side of the outer surface of the reverse osmosis membrane element, a water collection pipe fixedly connected to the middle of the inner cavity of the reverse osmosis membrane element, a heat insulation layer fixedly connected to the left side of the outer surface of the water collection pipe, a water inlet at the front left end of the reverse osmosis membrane element, a fixing device movably installed on the upper part of the outer surface of the reverse osmosis membrane element, a rotating rod movably connected to the right end of the reverse osmosis membrane element, and fixing columns movably connected to both the upper and lower parts of the outer surface of the reverse osmosis membrane element. In this technical solution, the threads on the left and right sides of the outer surface of the rotating shaft are reverse threads, facilitating cleaning of the inside of the reverse osmosis membrane element. The heat insulation layer prevents damage to the water collection pipe due to low winter temperatures. By incorporating the reverse osmosis membrane element, filter screen, reverse osmosis membrane, and isolation screen, the water purification effect can be improved.

[0004] However, the feed screens of existing reverse osmosis membrane elements are mostly conventional diamond-shaped mesh structures, which have limited guiding effect on the fluid, thick boundary layers on the membrane surface, significant concentration polarization, and insufficient anti-fouling ability. Furthermore, under high-pressure operation, slippage or bulging can easily occur between the membrane bag and the feed screen layers, affecting structural stability. In addition, during the interlayer reinforcement injection process in the winding process, existing equipment cannot accurately follow the surface position of the variable diameter membrane roll, which can easily interfere with the membrane roll, causing scratches or uneven coating on the membrane sheet, resulting in low production efficiency and yield. Summary of the Invention

[0005] The purpose of this application is to provide a spiral reverse osmosis membrane element and its preparation process to solve the problems in the prior art.

[0006] In a first aspect, this application provides a spiral reverse osmosis membrane element, which adopts the following technical solution: it includes a central permeate pipe, which is inserted into the shell. At least one membrane bag and at least one inlet screen are wound around the outer circumferential surface of the central permeate pipe. The membrane bag is formed by bonding two reverse osmosis membrane sheets together with sealant on three of their edges. Its opening edge is in fluid communication with the water collection hole of the central permeate pipe. A permeate flow channel cloth is provided inside the membrane bag. The feed water separator is woven from polymer filaments of a first thickness. Multiple spiral flow-guiding ribs of a second thickness, made of polymer material, are integrally formed on its upper and / or lower surfaces along the winding direction, with the second thickness being less than the first thickness. These spiral flow-guiding ribs abut against the surface of the reverse osmosis membrane when the membrane element is wound, guiding the feed water to flow in a spiral path within the channels between the membrane bags. Toughening and reinforcing adhesive is provided at the interlayer interface points between the membrane bags and the feed water separator. The cross-sectional shape of the spiral flow-guiding ribs is trapezoidal, and the height of the spiral flow-guiding ribs is 0.3 to 0.8 times the thickness of the feed water separator.

[0007] By adopting the above technical solution, the influent forms a forced spiral flow within the flow channel, effectively disrupting the concentration boundary layer on the membrane surface, enhancing turbulence, and significantly improving the membrane element's antifouling ability and separation efficiency. Simultaneously, the toughening and reinforcing adhesive dotted at the interlayer interface enhances the overall rigidity and operational reliability of the winding structure, preventing membrane bag bulging and interlayer slippage under high pressure, and extending the membrane element's service life. Furthermore, the trapezoidal cross-section facilitates demolding during hot pressing, and the narrower contact surface at the top reduces the friction area with the membrane. At the same time, the rib height ensures effective flow guidance and turbulence enhancement while avoiding excessive compression of the effective flow channel cross-section, which could lead to a significant increase in influent pressure drop.

[0008] Preferably, the spiral guide rib has a spiral angle of 10 to 45 degrees relative to the longitudinal edge of the inlet mesh, and the distance between two adjacent spiral guide ribs is 8 mm to 15 mm; the inlet mesh is a biaxially oriented polypropylene mesh, and the spiral guide rib is formed into an integral structure with the inlet mesh by a hot-pressing molding process.

[0009] By adopting the above technical solution, it is ensured that the ribs will not fall off under long-term high-pressure scouring; at the same time, while improving the anti-fouling performance, a low inlet flow resistance is maintained.

[0010] Preferably, the sealant is a photothermal dual-curing polyurethane acrylate adhesive, and the width of the adhesive line formed on the three edges of the membrane bag is 8-15 mm. The adhesive line has a recessed portion at the position corresponding to the spiral guide rib of the water inlet mesh, which is complementary to the shape of the spiral guide rib, so as to enhance the interlayer bonding stability after winding.

[0011] By adopting the above technical solution, the winding operation is convenient, and the subsequent heat curing ensures a high-strength bonding and sealing effect; the complementary fit between the concave and convex parts formed by the adhesive line and the spiral guide ribs makes the interlayer bonding of the winding more compact.

[0012] Secondly, this application also provides a process for preparing a spiral reverse osmosis membrane element, which includes the following steps: S1. Provide reverse osmosis membrane sheets, place two reverse osmosis membrane sheets opposite each other, place the product water flow channel cloth in the middle, and use a precision glue coating device to apply photothermal dual-curing sealant along three edges, and form a membrane bag with open edges after preliminary ultraviolet curing. S2. Multiple spiral guide ribs are integrally formed on at least one side of a woven biaxially oriented polypropylene mesh substrate by hot pressing to obtain a water inlet mesh. S3. Using a winding and curing device, align and fix the opening edge of the membrane bag with the water collection hole of the central water pipe. Under the action of the winding driving force, wind the membrane bag and the water inlet screen together onto the central water pipe. S4. During the winding process, a dispensing unit dynamically injects toughening and reinforcing adhesive into the interlayer interface between the membrane bag and the water inlet mesh along a preset path. At the same time, the dispensing unit locally heats the outer layer of the membrane element that has just been wound to accelerate the deep curing of the sealant and the setting of the toughening and reinforcing adhesive. S5. Perform overall thermosetting treatment and end trimming on the wound membrane element preform, and then assemble it into the shell to obtain the spiral reverse osmosis membrane element.

[0013] By adopting the above technical solution, the production steps are simplified and the manufacturing efficiency is improved. Furthermore, the precise injection of toughening and reinforcing adhesive and local heating and shaping are carried out simultaneously during the winding process, which not only enhances the structural strength of the membrane element but also shortens the overall curing cycle, ensuring the dimensional consistency and performance stability of the product.

[0014] Preferably, the toughening and reinforcing adhesive is an epoxy resin-rubber particle composite adhesive, and its injection amount is 0.05-0.2 g / m.

[0015] By adopting the above technical solution, it has both high bonding strength and flexibility, which can effectively absorb stress impact during operation, meet the interlayer reinforcement requirements, and avoid excessive glue clogging the water inlet channel.

[0016] Preferably, the dispensing unit includes a Z-axis linear module, an X-axis linear module is connected to the front movable end of the Z-axis linear module, a Y-axis linear module is connected to the top movable end of the X-axis linear module, and an intermittent dispensing mechanism is installed on the top movable end of the Y-axis linear module, one end of which is connected to an external glue source.

[0017] By adopting the above technical solution, a motion platform for the dispensing unit is built using a three-axis linear module, enabling the intermittent dispensing mechanism to move freely and be precisely positioned in three-dimensional space, thereby following the constantly changing film roll radius and interface position during the winding process in real time.

[0018] Preferably, the intermittent adhesive application mechanism includes a pad whose bottom side is fastened to the top moving end of the Y-axis linear module. A carrier is horizontally and vertically fixed to the left rear side of the pad, and a drive structure is installed at the angle between the pad and the carrier. A spring is installed on the left front part of the carrier, and the front side of the spring abuts against the drive structure. A slide plate is connected to the left end of the drive structure, and the middle right side of the slide plate is inserted into the left side of the slide block. The right side of the slide block is fixed to the carrier, and a spot coating structure is fastened to the left side of the slide plate.

[0019] By adopting the above technical solution, stable reciprocating drive of the dot coating structure in the winding tangential direction is achieved, resulting in a compact structure and high guiding accuracy.

[0020] Preferably, the drive structure includes a base plate fixedly connected to the bottom of the angle between the pad and the carrier. A first motor and a second motor are respectively locked and fixed to the front and rear sides of the bottom of the base plate. The top output end of the first motor is connected to a lead screw. An internal threaded sleeve is threaded to the upper part of the outer surface of the lead screw, and the bottom of the lead screw passes through and rotates inside the base plate. The internal threaded sleeve is embedded in the front side of the support block. An arc-shaped opening is provided at the rear of the support block, and a cam disk assembly is rotatably connected to the inner side of the arc-shaped opening. A key rod is provided through the cam disk assembly. The top ends of the lead screw and the key rod are rotatably connected to the pad, and the rear of the pad is fixed to the carrier. The bottom of the key rod is connected to the top output end of the second motor. A roller is connected to the left side of the cam disk assembly. The roller is rotatably connected to the inner side of the right end of the hook rod, and a support is rotatably connected to the bend of the hook rod. The rear side of the support is fixed to the carrier. A push rod is rotatably connected to the left end of the hook rod, and the end of the push rod away from the hook rod is connected to the slide plate.

[0021] By adopting the above technical solution, the drive structure controls the axial lifting and lowering of the cam disk assembly by the first motor to select the working cam plate, and the second motor drives the cam disk assembly to rotate. Through the lever transmission chain composed of the cam profile, roller, hook rod and push rod, the rotational motion is converted into the linear reciprocating motion of the slide plate, realizing the adjustability of the dispensing stroke amplitude and the flexible switching between dispensing and avoidance actions.

[0022] Preferably, the cam disk assembly is composed of multiple cams whose maximum radial dimension increases sequentially from top to bottom, and the multiple cams are flush on one side and extend outward sequentially from top to bottom on the other side.

[0023] By adopting the above technical solution, different cam plates with different lifting strokes can be switched to work simply by adjusting the lifting height of the cam plate assembly. This allows for rapid changes in the reciprocating stroke of the slide plate without replacing mechanical parts, thus meeting the different stroke requirements of dispensing and large-scale lifting and avoidance actions.

[0024] Preferably, the dot coating structure includes a vertical plate that is fastened to the right side of the slide plate, and a positioning frame is locked and fixed on both the front and rear sides of the left side of the vertical plate. A sleeve is provided inside the two positioning frames, and a glue dispensing head is provided through the inner side of the two sleeves. A hot air module is locked and fixed inside the two positioning frames, and the front side of the glue dispensing head is connected to an external glue source end through a pipe.

[0025] By adopting the above technical solution, the freshly applied adhesive dots can be immediately shaped with hot air while the adhesive is being applied, effectively preventing the adhesive from flowing or deforming during subsequent winding and extrusion. This ensures the shape and positional accuracy of the toughening and reinforcing adhesive dots, thereby improving the regularity of the internal structure of the membrane element and its operational reliability.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. The spiral reverse osmosis membrane element provided in this application, by integrally forming multiple trapezoidal cross-section spiral guiding ribs on the feed water mesh, and having the ribs abut against the surface of the reverse osmosis membrane in the wound state, can force the formation of a three-dimensional spiral flow path in the feed water channel between the membrane bags. This structure can effectively destroy the concentration boundary layer on the membrane surface, enhance the turbulence of the fluid, significantly reduce concentration polarization and the tendency of suspended solids to deposit on the membrane surface, thereby greatly improving the antifouling performance and long-term operational stability of the membrane element; at the same time, the complementary fit between the spiral guiding ribs and the membrane bag sealing adhesive line further enhances the bonding reliability and structural integrity between the wound layers, effectively preventing interlayer slippage or membrane bag bulging under high pressure conditions, and extending the service life of the membrane element.

[0027] 2. In terms of the manufacturing process, this application adopts a photothermal dual-curing sealant combined with a process route of simultaneous heating during UV pre-curing and winding. This not only ensures the forming accuracy of the membrane bag and the convenience of the winding operation, but also allows the sealant to gradually reach the required bonding strength during the winding process, shortening the post-curing time and improving production efficiency. Furthermore, during the winding process, toughening and reinforcing adhesive is injected in dots, with the adhesive dots distributed along the extension path of the spiral guide ribs. This not only enhances the bonding force and deformation resistance between the membrane bag and the water inlet mesh layer, but also avoids continuous blockage of the water inlet channel, maintaining good hydraulic conductivity.

[0028] 3. The preparation process of this application is equipped with a dispensing unit with three-axis linear linkage and intermittent dispensing function. Through the drive structure and multi-stage cam disk assembly, the dispensing head can accurately follow the membrane roll interface according to the real-time change of the winding radius, and can flexibly switch between dispensing and avoidance states. This solves the problems of interference, scratches and adhesive splashing caused by the increase of membrane roll radius and surface undulation in traditional winding dispensing processes, and significantly improves the automation level, product consistency and yield of membrane element manufacturing process. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the membrane element structure of this application; Figure 2 This is a schematic diagram of the connection between the membrane bag and the inlet screen in this application; Figure 3 This is a schematic diagram of the connection between the inlet baffle and the spiral guide ribs in this application; Figure 4 This is a schematic diagram of the dispensing unit of this application; Figure 5 This is a schematic diagram of the intermittent glue application mechanism of this application; Figure 6 This is a schematic diagram of the driving structure of this application; Figure 7 This is a schematic diagram of the dot-painted structure of this application; Figure 8 This is a schematic diagram of applying sealant to a reverse osmosis membrane using a precision coating device.

[0030] Explanation of reference numerals in the attached diagram: 1. Central permeate pipe; 2. Membrane bag; 3. Inlet filter; 4. Outer shell; 5. Toughening and reinforcing adhesive; 21. Reverse osmosis membrane; 22. Sealant; 23. Permeate flow channel fabric; 31. Spiral guide ribs; 6. Z-axis linear module; 7. X-axis linear module; 8. Y-axis linear module; 9. Intermittent adhesive application mechanism; 91. Pad; 92. Carrier; 93. Drive structure; 94. Spring; 95. Slide plate; 96. Slide seat; 97. 7. Dot coating structure; 931. Base plate; 932. First motor; 933. Second motor; 934. Lead screw; 935. Internal threaded sleeve; 936. Support block; 937. Cam plate assembly; 938. Key rod; 939. Pad block; 9310. Roller; 9311. Hook rod; 9312. Support; 9313. Push rod; 971. Vertical plate; 972. Positioning frame; 973. Sleeve; 974. Dispensing head; 975. Air-heating module. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1 -Appendix Figure 8 This application will be described in further detail below.

[0032] Implementation 1: A spiral reverse osmosis membrane element.

[0033] Please see Figures 1 to 3 This embodiment provides a spiral reverse osmosis membrane element, including a central permeate pipe 1, which is inserted into the housing 4. At least one membrane bag 2 and at least one inlet water separator 3 are wound around the outer circumference of the central permeate pipe 1. The membrane bag 2 and the inlet water separator 3 are alternately stacked and wound into a cylindrical shape, and the whole is placed inside the housing 4.

[0034] The membrane bag 2 is formed by bonding two reverse osmosis membrane sheets 21 together with sealant 22 on three sides; the central permeate pipe 1 is a circular pipe with multiple radial water collection holes, which is used to collect the permeate water that has passed through the reverse osmosis membrane sheets 21 and lead it out of the membrane element; the opening edge of the membrane bag 2 is in fluid communication with the water collection hole of the central permeate pipe 1; a flexible permeate flow channel cloth 23 with a flow guiding function is sandwiched inside the membrane bag 2, which is used to smoothly guide the permeate water to the central permeate pipe 1.

[0035] The inlet screen 3 is woven from polymer filaments with a first thickness (i.e., the overall thickness of the inlet screen 3). Its upper and / or lower surfaces are integrally formed with multiple spiral flow guiding ribs 31 made of polymer material with a second thickness along the winding direction. The second thickness, i.e., the height of the spiral flow guiding ribs 31, is less than the first thickness of the inlet screen 3. When the membrane element is wound, the multiple spiral flow guiding ribs 31 abut against the surface of the reverse osmosis membrane 21, thereby supporting multiple spiral fluid channels in the flow channel between the membrane bags 2, guiding the inlet water to flow in a spiral path in the flow channel.

[0036] In this embodiment, the cross-sectional shape of the spiral guide rib 31 is preferably trapezoidal. The trapezoidal structure, being narrower at the top and wider at the bottom, facilitates demolding during hot pressing, and the narrower contact surface at the top reduces the friction area with the diaphragm. Furthermore, the height of the spiral guide rib 31 is 0.3 to 0.8 times the thickness of the inlet mesh 3, for example, 0.5 times. If the height is too small, the guiding and turbulence enhancement effects will be insignificant; if the height is too large, it will excessively compress the effective flow channel cross-section, increasing the inlet pressure drop. The top width of the trapezoidal cross-section is 1 / 3 to 1 / 2 of the bottom width.

[0037] Specifically, the spiral guide ribs 31 have a spiral angle of 10 to 45 degrees relative to the longitudinal edge of the inlet mesh 3, preferably 25 degrees; the spacing between two adjacent spiral guide ribs 31 is 8 mm to 15 mm, preferably 10 mm; the substrate of the inlet mesh 3 is preferably made of biaxially oriented polypropylene mesh, which has good chemical stability and mechanical strength; the spiral guide ribs 31 are formed into an integral structure with the substrate of the inlet mesh 3 through a hot pressing molding process, ensuring that the ribs will not fall off under the scouring of high-pressure water flow.

[0038] The sealant 22 is preferably a photothermal dual-curing polyurethane acrylate adhesive, which can quickly surface dry and set under ultraviolet light, facilitating winding operations; it can deeply cross-link during subsequent thermal curing, providing high-strength adhesion; the width of the adhesive line formed on the three edges of the membrane bag 2 is 8-15 mm; in particular, at the position corresponding to the spiral guide rib 31 of the water inlet mesh 3, the adhesive line naturally forms a recessed part that complements the shape of the spiral guide rib 31 under the action of winding pressure. This concave-convex structure significantly enhances the bonding stability and shear resistance between adjacent membrane bag layers after winding.

[0039] In addition, at the interlayer interface between the membrane bag 2 and the inlet mesh 3, multiple toughening and reinforcing adhesive points 5 are arranged along the winding direction. The toughening and reinforcing adhesive 5 is preferably an epoxy resin-rubber particle composite adhesive, with an injection amount of 0.05-0.2 g / m. It can not only further enhance the interlayer bonding force and prevent the membrane bag from bulging during operation, but its dotted distribution also avoids the formation of a continuous flow barrier and does not affect the normal flow of inlet water in the flow channel.

[0040] Example 2: A process for preparing a spiral reverse osmosis membrane element.

[0041] This embodiment provides a process for preparing a spiral reverse osmosis membrane element as described in Example 1, comprising the following steps S1 to S5.

[0042] Step S1: Preparation of membrane bag 2.

[0043] Provide a roll of reverse osmosis membrane sheets 21, place two reverse osmosis membrane sheets 21 opposite each other, and place the permeate flow channel cloth 23 between them, then, as... Figure 8 As shown, a precision adhesive applicator is used to evenly apply a photothermal dual-curing sealant 22 along the three edges. After the sealant is applied, an ultraviolet light source is immediately used to pre-cur the sealant line, so that its surface is shaped and has a certain bonding strength, thereby forming a semi-finished film bag 2 with three sealed sides and one open side.

[0044] Step S2: Preparation of inlet screen 3.

[0045] A pre-woven biaxially oriented polypropylene mesh substrate is provided. A pair of heating rollers with spiral groove patterns on their surfaces are used to hot press the mesh substrate. The spiral groove pattern has a preset spiral angle relative to the axis of the heating rollers. During the hot pressing process, molten polypropylene material is quantitatively supplied into the spiral groove pattern through an extruder. After cooling, multiple spiral guide ribs 31 are integrally formed on the surface of the mesh substrate to obtain the water inlet mesh 3. By changing the heating rollers with different spiral groove patterns, the spiral angle and spacing of the ribs can be easily adjusted.

[0046] Step S3: Winding preparation and initial winding.

[0047] Using a winding and curing device, firstly, precisely align the opening edge of the membrane bag 2 obtained in step S1 with the water collection hole on the central water production pipe 1, and pre-fix it using clamps or tape; then load the water inlet mesh 3 obtained in step S2 and the pre-fixed membrane bag 2 onto the feeding mechanism of the device, start the device, and under tension control, alternately stack the membrane bag 2 and the water inlet mesh 3, and wind them together onto the central water production pipe 1.

[0048] Step S4: Simultaneously follow the dispensing and curing.

[0049] During the winding process, the dispensing unit mounted on the equipment is activated and performs the following operations: The dispensing unit dynamically injects toughening and reinforcing adhesive 5 into the interlayer interface between the membrane bag 2 and the inlet mesh 3 along a preset path. This preset path preferably matches the extension path of the spiral guide ribs 31 on the inlet mesh 3 to ensure that the adhesive dots are distributed near the rib support positions that require the most reinforcement. At the same time, the heating module integrated in the dispensing unit locally heats the outer layer of the membrane element that has just been wound, with the temperature controlled between 80°C and 120°C. This local heating has two functions: first, it accelerates the deep thermal curing of the membrane bag edge sealant 22; second, it allows the injected toughening and reinforcing adhesive 5 to quickly set, preventing it from being squeezed and flowing during subsequent winding.

[0050] To achieve the aforementioned precise and interference-free synchronous operation, this process employs a dispensing unit with a specific structure, which will be discussed below. Figures 4 to 7 Its detailed structure and operating principle are explained.

[0051] like Figure 4 As shown, the dispensing unit includes a Z-axis linear module 6, an X-axis linear module 7, a Y-axis linear module 8, and an intermittent dispensing mechanism 9. The Z-axis linear module 6 is vertically mounted on the equipment frame, and its front moving end is connected to the X-axis linear module 7 for driving subsequent components to move along the Z-axis (i.e., the vertical direction). The top moving end of the X-axis linear module 7 is connected to the Y-axis linear module 8 for driving subsequent components to move along the X-axis (i.e., parallel to the central water pipe axis). The top moving end of the Y-axis linear module 8 is equipped with the intermittent dispensing mechanism 9 for driving the mechanism to move along the Y-axis (i.e., the horizontal radial direction perpendicular to the central water pipe axis). Through the linkage of the three linear modules, the intermittent dispensing mechanism 9 can be driven to any coordinate in the workspace to follow the variable diameter winding contact wire.

[0052] like Figures 5 to 7As shown, the intermittent glue application mechanism 9 includes a pad 91 whose bottom side is fastened to the top moving end of the Y-axis linear module 8; a carrier 92 is horizontally and vertically fixed to the left rear side of the pad 91, and the carrier 92 is L-shaped; a drive structure 93 is installed in the space formed by the pad 91 and the carrier 92; a spring 94 is installed on the left front part of the carrier 92, and the front side of the spring 94 abuts against a movable part of the drive structure 93 to provide a reset spring force; a slide plate 95 is connected to the left end of the drive structure 93, and the middle right side of the slide plate 95 is inserted into the left side of the slide block 96. The right side of the slide block 96 is fixed to the carrier 92, so that the slide plate 95 can move precisely in a straight line along the slide block 96 under the drive of the drive structure 93; a spot coating structure 97 is fastened to the left side of the slide plate 95.

[0053] The drive structure 93 includes a base plate 931 fixedly connected to the bottom of the included angle position of the pad 91 and the carrier 92. A first motor 932 and a second motor 933 are respectively locked and fixed on the front and rear sides of the bottom of the base plate 931. The top output end of the first motor 932 is connected to the lead screw 934. The upper part of the outer surface of the lead screw 934 is threaded with an internal thread sleeve 935, and the bottom of the lead screw 934 passes through and rotates inside the base plate 931. The internal thread sleeve 935 is embedded and fixed inside the front side of a support block 936. The rear part of the support block 936 has an arc-shaped opening, and the inner side of the arc-shaped opening is rotatably connected to a cam disk assembly 937 through a bearing. A key rod 938 is provided through the center of the cam disk assembly 937. The key rod 938 and the cam disk assembly 937 are circumferentially fixed and axially slidingly fitted through a spline or guide key.

[0054] The top ends of the lead screw 934 and key rod 938 are rotatably connected to a pad 939, and the rear of the pad 939 is fixed to the carrier 92, providing stable support for the top of the transmission component; the bottom of the key rod 938 is connected to the top output end of the second motor 933; the left contour surface of the cam disk assembly 937 is always in contact with a roller 9310; the roller 9310 is rotatably connected to the inner side of the right end of the hook rod 9311, and the turning point of the hook rod 9311 is rotatably connected to a support 9312 by a pin, and the rear side of the support 9312 is fixed to the carrier 92, thus forming a lever fulcrum; the left end of the hook rod 9311 is rotatably connected to a push rod 9313 by a pin, and the end of the push rod 9313 away from the hook rod 9311 is connected to the slide plate 95.

[0055] The working process of the drive structure 93 is as follows: The first motor 932 rotates, driving the lead screw 934 to rotate, which in turn drives the support block 936 and the cam disk assembly 937 mounted on it to move up and down along the axial direction of the lead screw 934 through the internal threaded sleeve 935. Since the cam disk assembly 937 is connected to the second motor 933 through the key rod 938, it can still maintain the transmission relationship with the second motor 933 during the lifting process. The second motor 933 rotates, driving the cam disk assembly 937 to rotate through the key rod 938. The rotation of the cam disk assembly 937 will periodically push the roller 9310 through its changing contour radius, causing the hook rod 9311 to swing around the support 9312. The swing of the hook rod 9311 is converted into the linear reciprocating motion of the slide plate 95 along the slide block 96 through the push rod 9313, which finally drives the dot coating structure 97 to move back and forth.

[0056] In this embodiment, the cam disk assembly 937 is composed of multiple cams whose maximum radial dimension increases sequentially from top to bottom. One side of each cam is flush with the other, while the other side extends outwards sequentially from top to bottom, forming a stepped shape. This allows the cam disk assembly 937 to be raised and lowered by the first motor 932, enabling the selection of cams with different profile sizes to contact the roller 9310, thereby precisely adjusting the reciprocating stroke of the slide plate 95. For example, when a smaller dispensing motion is required, the cam disk assembly 937 is raised to engage the smaller upper cam; when a larger avoidance and lifting motion is required, the cam disk assembly 937 is lowered to engage the larger lower cam. Combined with the coordinated control of the first motor 932 and the second motor 933, complex dispensing and lifting motions can be achieved.

[0057] In addition, the dot coating structure 97 includes a vertical plate 971 that is fastened to the right side of the slide plate 95. A positioning frame 972 is locked and fixed on both the front and rear sides of the left side of the vertical plate 971. A retainer 973 is provided inside the two positioning frames 972. A glue dispensing head 974 is clamped and fixed through the two retainers 973. The glue dispensing head 974 is connected to an external glue source (such as a precision metering pump) through a flexible tube. A heat pump module 975 is also locked and fixed inside the two positioning frames 972. The heat pump module 975 integrates a heating wire and a fan. Its air outlet faces the area below the tip of the glue dispensing head 974.

[0058] During step S4, the control system drives the X-axis and Y-axis linear modules based on real-time feedback of the winding radius to ensure that the dispensing head 974 of the dispensing structure 97 is always aligned with the target position of the water inlet screen 3 (e.g., the side or back of the spiral guide rib 31). The Z-axis linear module is used for initial tool setting height adjustment. When dispensing is required, the drive structure 93 pushes the dispensing head 974 forward slightly, and the adhesive is squeezed out and adhered to the interlayer. In path sections where dispensing is not required or interference may occur, the drive structure 93 quickly pulls the dispensing head 974 back, while the Y-axis linear module cooperates to make radial retraction, thereby achieving interference-free dynamic operation. At the same time, the hot air module 975 continuously blows hot air to heat and shape the newly dispensed area in real time.

[0059] Step S5; Post-processing and assembly.

[0060] The wound membrane element preform is placed in an oven for overall heat curing treatment, so that the sealant 22 and the toughening and reinforcing adhesive 5 are completely cured and cross-linked to achieve the final bonding strength. After curing, the two ends of the membrane element are trimmed and chamfered, and accessories such as sealing rings are installed. Finally, the whole thing is pushed into the shell 4 to complete the manufacturing of the spiral reverse osmosis membrane element.

[0061] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A fabrication process for a spiral reverse osmosis membrane element, characterized in that, Includes the following steps: S1. Provide reverse osmosis membrane (21), place two reverse osmosis membranes (21) opposite each other, place a product water flow channel cloth (23) in the middle, and use a precision glue applicator to apply photothermal dual-curing sealant (22) along the three edges, and form a membrane bag (2) with an open edge after preliminary ultraviolet curing. S2. Multiple spiral guide ribs (31) are integrally formed on at least one side of the woven biaxially oriented polypropylene mesh substrate by hot pressing molding process to obtain the water inlet mesh (3). S3. Using a winding and curing device, align and fix the opening edge of the membrane bag (2) with the water collection hole of the central water pipe (1). Under the action of the winding driving force, wind the membrane bag (2) and the water inlet mesh (3) together onto the central water pipe (1). S4. During the winding process, a dispensing unit dynamically injects toughening and reinforcing adhesive (5) into the interlayer interface between the membrane bag (2) and the water inlet mesh (3) along a preset path. At the same time, the dispensing unit locally heats the outer layer of the membrane element that has just been wound to accelerate the deep curing of the sealant (22) and the shaping of the toughening and reinforcing adhesive (5). S5. Perform overall thermosetting treatment and end trimming on the wound membrane element preform, and then assemble it into the shell (4) to obtain the spiral reverse osmosis membrane element. The dispensing unit includes a Z-axis linear module (6), an X-axis linear module (7) connected to the front moving end of the Z-axis linear module (6), a Y-axis linear module (8) connected to the top moving end of the X-axis linear module (7), and an intermittent dispensing mechanism (9) installed on the top moving end of the Y-axis linear module (8). One end of the intermittent dispensing mechanism (9) is connected to an external glue source. The intermittent glue application mechanism (9) includes a pad (91) whose bottom side is fastened to the top moving end of the Y-axis linear module (8). A carrier (92) is horizontally and vertically fixed on the left rear side of the pad (91). A drive structure (93) is installed at the angle between the pad (91) and the carrier (92). A spring (94) is installed on the left front part of the carrier (92). The front side of the spring (94) abuts against the drive structure (93). A slide plate (95) is connected to the left end of the drive structure (93). The middle right side of the slide plate (95) is inserted into the left side of the slide block (96). The right side of the slide block (96) is fixed to the carrier (92). A spot coating structure (97) is fastened to the left side of the slide plate (95).

2. The fabrication process of a spiral reverse osmosis membrane element according to claim 1, characterized in that: The drive structure (93) includes a base plate (931) fixedly connected to the bottom of the angle between the pad (91) and the carrier (92). A first motor (932) and a second motor (933) are respectively locked and fixed to the front and rear sides of the bottom of the base plate (931). The top output end of the first motor (932) is connected to the lead screw (934). The upper part of the outer surface of the lead screw (934) is threaded with an internal thread sleeve (935), and the bottom of the lead screw (934) rotates through the inside of the base plate (931). The internal thread sleeve (935) is embedded in the front side of the support block (936). The rear part of the support block (936) has an arc-shaped opening, and a cam disk assembly (937) is rotatably connected to the inner side of the arc-shaped opening. A key is provided through the inside of the cam disk assembly (937). The top ends of the rod (938), the lead screw (934), and the key rod (938) are rotatably connected to the pad (939), and the rear of the pad (939) is fixed to the carrier (92). The bottom of the key rod (938) is connected to the top output end of the second motor (933). The left side of the cam disk assembly (937) is connected to a roller (9310), which is rotatably connected to the inner side of the right end of the hook rod (9311). The hook rod (9311) is rotatably connected to a support (9312) at the turning point. The rear side of the support (9312) is fixed to the carrier (92). The left end of the hook rod (9311) is rotatably connected to a push rod (9313), and the end of the push rod (9313) away from the hook rod (9311) is connected to the slide plate (95).

3. The fabrication process of a spiral reverse osmosis membrane element according to claim 2, characterized in that: The cam disk assembly (937) is composed of multiple cams whose maximum radial dimension increases sequentially from top to bottom, with one side of each cam being flush with the other side extending outward sequentially from top to bottom.

4. The fabrication process of a spiral reverse osmosis membrane element according to claim 1, characterized in that: The dot coating structure (97) includes a vertical plate (971) that is fastened to the right side of the slide plate (95). A positioning frame (972) is locked and fixed on both the front and rear sides of the left side of the vertical plate (971). A sleeve (973) is provided inside the two positioning frames (972). A glue outlet (974) is provided through the inside of the two sleeves (973). A hot air module (975) is locked and fixed inside the two positioning frames (972). The front side of the glue outlet (974) is connected to an external glue source end through a pipe.

5. The reverse osmosis membrane element prepared according to the preparation process of the spiral reverse osmosis membrane element according to claim 1 includes a central permeate pipe (1), the central permeate pipe (1) is inserted into the shell (4), at least one membrane bag (2) and at least one inlet screen (3) are wound around the outer circumferential surface of the central permeate pipe (1), the membrane bag (2) is formed by bonding two reverse osmosis membrane sheets (21) on its three edges with sealant (22), its opening edge is in fluid communication with the water collection hole of the central permeate pipe (1), and a permeate flow channel cloth (23) is provided inside the membrane bag (2). Its features are: The inlet mesh (3) is woven from polymer filaments of a first thickness. Its upper and / or lower surfaces are integrally formed with multiple spiral guide ribs (31) of polymer material of a second thickness along the winding direction, and the second thickness is less than the first thickness. The multiple spiral guide ribs (31) abut against the surface of the reverse osmosis membrane (21) in the winding state of the membrane element, and are used to guide the inlet water to flow in a spiral path in the flow channel between the membrane bags (2). The interlayer interface arrangement points of the membrane bags (2) and the inlet mesh (3) are provided with toughening and reinforcing adhesive (5). The cross-sectional shape of the spiral guide ribs (31) is trapezoidal, and the height of the spiral guide ribs (31) is 0.3 to 0.8 times the thickness of the inlet mesh (3).

6. The reverse osmosis membrane element according to claim 5, characterized in that: The spiral guide rib (31) has a spiral angle of 10 to 45 degrees relative to the longitudinal edge of the water inlet mesh (3), and the distance between two adjacent spiral guide ribs (31) is 8 mm to 15 mm; the water inlet mesh (3) is a biaxially stretched polypropylene mesh, and the spiral guide rib (31) is formed into an integral structure with the water inlet mesh (3) by hot pressing molding process.

7. The reverse osmosis membrane element according to claim 5, characterized in that: The sealant (22) is a photothermal dual-curing polyurethane acrylate adhesive. The width of the adhesive line formed on the three edges of the membrane bag (2) is 8-15 mm. The adhesive line forms a recessed part at the position corresponding to the spiral guide rib (31) of the water inlet mesh (3) that is complementary to the shape of the spiral guide rib (31) to enhance the interlayer bonding stability after winding.

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