Casting process of hollow fiber membrane module

Abstract

The invention relates to a casting process for a liquid outlet end of a hollow fiber membrane module, provides an improved process and designs a special glue distributor aiming at an end sealing process of a common hollow fiber membrane module, improves a rotary glue filling process of a hollow fiber membrane through the distributor, and improves the production yield and the production efficiency of the hollow fiber membrane. And the cost of the production process is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of membrane separation, and in particular to a casting process flow of a hollow fiber membrane component. Background Art

[0002] Hollow fiber membrane separation technology is a high-tech technology widely used in water purification, liquid separation / purification / concentration. Due to the large specific surface area of ​​hollow fiber membrane materials, relatively small absolute volume and mass, simple application conditions, good filtration efficiency, and low material cost, it has very wide applications in the field of membrane separation technology, and is widely used in medicine, fine chemicals, environmental protection, drinking water treatment and other fields.

[0003] In the common water treatment industry, hollow fiber membranes play an important role. The core of most water filtration components in the industry is hollow fiber membranes, which use the excellent interception ability brought by small pore size to filter out particles of a certain size in the water through physical interception. Common hollow fiber membranes are divided into two types according to the direction of pressure during filtration: internal pressure membrane and external pressure membrane. According to the different locations of water outlet, they are divided into: pressure membrane assembly and immersed membrane assembly. Driven by pressure, smaller particles in the raw water, such as water molecules and ions, can pass through the membrane pores to the other side, while larger particles, such as bacteria, colloids, large impurities, and polymers, cannot pass through the membrane pores, thereby achieving the interception effect. The filtration process can be carried out at room temperature.

[0004] In the civilian water purifier industry, hollow fiber membranes are difficult to put into practical use because of their relatively low production yield and production efficiency. In the production process of hollow fiber membranes, the commonly used polyurethane resin will produce a large number of bubbles in the glue layer during the curing process due to its hydrophilicity, resulting in unqualified products. Secondly, the common production process can only produce 1-2 at a time, and when producing multiple at the same time, it is difficult to ensure that the amount of glue poured into each ultrafiltration membrane component is similar. Summary of the invention

[0006] The purpose of the present invention is to provide a casting process for a hollow fiber membrane assembly, which can improve the quality of the membrane assembly glue filling and sealing, improve the accuracy and uniformity of the glue filling through a special jig, reduce the manufacturing cost, and use supporting equipment to improve production efficiency and production yield.

[0007] To achieve the above-mentioned purpose of the invention: a set of casting equipment for hollow fiber membrane components, including: a membrane bundle and a membrane shell, a liquid inlet end fixture connected to the membrane shell, a membrane thread sealing machine, a membrane tube shearing machine, a special glue dispenser, a horizontal centrifugal platform, a polyurethane potting resin for end sealing, and one or more isocyanate curing agents.

[0008] A casting process for a hollow fiber membrane, characterized in that: a membrane bundle is placed in a membrane shell, and the membrane bundle is characterized in that: after the membrane bundle is folded in half, the membrane hole end is tied and fixed. The membrane hole end of the membrane bundle is heated and sealed with a sealing machine, and after sealing, a glue inlet fixture is installed at the membrane hole end, and the glue inlet fixture is characterized in that: an annular groove is provided on the inner wall of the glue inlet fixture, and a snowflake-shaped flow channel is provided at the bottom, the membrane hole end of the membrane bundle is close to the flow channel, and a glue inlet pipe A is provided outward along the flow channel, and the inner diameter of the glue inlet fixture is slightly larger than the outer diameter of the membrane shell. After fixing the glue inlet fixture, the membrane shell equipped with the membrane bundle is fixed on a separate annular groove on a horizontal centrifugal platform, and the annular groove is characterized in that: the inner diameter of the groove is slightly larger than the outer diameter of the membrane shell. Then, the glue inlet pipe of the glue dispenser is inserted into the glue inlet mold. The glue dispenser is characterized in that: a downward hemispherical container is provided at each of the four corners, and a glue inlet pipe B extends from the lower end of the container. The outer diameter of the glue inlet pipe B is equivalent to the inner diameter of the glue inlet pipe A. The glue dispenser is fixed by four positioning columns on a horizontal centrifugal platform, and then the resin is poured in and centrifuged, and then left to stand for a period of time until it is completely cured, and the excess resin at the membrane hole end is cut to expose the membrane hole.

[0009] In the above technical solution, both ends of the membrane tube are completely hollowed out, a plurality of water inlet holes are opened on the top of the tube, an annular protrusion is provided near the bottom of the tube, and a square protrusion positioning block is provided in the middle of the membrane tube.

[0010] In the above technical solution, an annular groove is provided on the inner wall of the glue inlet mold, a snowflake-shaped glue flow channel is provided at the bottom, and a glue inlet short tube A extends along the flow channel to the outside of the mold, and the annular groove is slightly smaller than the outer diameter of the annular protrusion on the above-mentioned membrane tube.

[0011] In the above technical solution, the glue dispenser is characterized in that: it is cross-shaped as a whole, with a round hole on the top, a sealed cover installed on the round hole, and downward hemispherical containers are respectively provided on the four corners of the tool, and a glue inlet pipe B extends from the lower end of the container. The outer diameter of the glue outlet pipe B is equivalent to the inner diameter of the above-mentioned glue inlet pipe A, and positioning rings are provided at the four corners of the distribution tool.

[0012] In the above technical solution, the sealed cover is provided with two interfaces, and the two interfaces are respectively connected to two fluid pipelines, one pipeline is used to transmit glue liquid, and the other pipeline is used to transmit nitrogen.

[0013] In the above technical solution, the difference between the outer diameter of the annular groove and the outer diameter of the annular protrusion is preferably 0.2 mm.

[0014] In the above technical solution, the center of the horizontal centrifugal platform is hollowed out and provided with an annular transmission structure, and a plurality of separate annular slots are provided along the four symmetrical directions of the center circle, with several slots in each direction, the inner diameter of the slot is slightly larger than the outer diameter of the membrane tube, and a plurality of positioning columns are symmetrically distributed around the center circle.

[0015] In the above technical solution, the number of annular slots is preferably 12, and preferably 3 in each direction.

[0016] In the above technical solution, the number of positioning columns is preferably 4.

[0017] A casting process for a hollow fiber membrane, characterized in that the method specifically comprises the following steps: (1) Folding the hollow fiber membrane into a bundle, bundling the membrane hole ends, using a sealing machine to cut the membrane filaments neatly, and then sealing the holes at high temperature to obtain a semi-finished membrane bundle; (2) Place the semi-finished membrane bundle in the membrane shell, with the membrane hole end protruding out of the membrane shell. The protruding length needs to just touch the bottom of the glue inlet jig. Then press the glue inlet jig toward the bottom of the membrane tube until the annular groove inside the jig matches the annular protrusion on the membrane tube, and fix the jig to the bottom of the membrane tube. (3) Inject the polyurethane resin component A and the isocyanate curing agent component B into two constant temperature stirring tanks respectively, and continue stirring at 20-30°C to ensure that the components are uniform and at a constant temperature; (4) Pour a certain ratio of A / B components into the same stirring tank, stir at 25-30°C, stop stirring after 3 minutes, start the vacuum degassing device until the bubbles disappear, and prepare the end-capping glue solution for use; (5) Match the square positioning block on the membrane shell with the square groove inside the annular groove, so that the membrane shell lies flat on the annular groove of the horizontal centrifugal platform, with the glue inlet fixture facing outward, and rotate the movable side C of the annular groove until the magnet is completely immersed in the funnel-shaped groove on the fixed side, then position the glue dispenser according to the positioning column, insert the glue inlet pipe B into the glue inlet pipe A, and press it to the bottom; (6) After fixing the membrane tube, put the airtight cover connected to the fluid pipeline on the glue dispenser, and then pour the glue into the glue dispenser through the flow channel. After pouring the glue, slowly introduce nitrogen, and then start the centrifugal platform at a speed of 500-1000rpm. Centrifuge for 15-20 minutes and then stop. Let it stand for 30-60 minutes and wait for the curing degree to reach the standard; (7) Cut off the excess resin at the bottom of the membrane shell together with the glue inlet tool to expose the membrane pores, leaving the membrane pores open to obtain the liquid outlet end of the membrane assembly.

[0017] Preferably, the sealing temperature in step (1) is 300-400°C, and the sealing time is 5-10s.

[0018] Preferably, the polyurethane glue in step (3) is a room temperature curing glue.

[0019] Preferably, the composite modified polyurethane component A and the isocyanate curing agent component B are mixed in a weight ratio of 100:80-100. The components A and B are respectively composed of the following weight ratios: Polyurethane potting compound component A: Polyurethane: 85%-100%; Active diluent: 0-10%; Isocyanate curing agent component B: Isocyanate curing agent: 90%-100%; Functional additives: 0-10%;

[0020] Preferably, in step (3), the curing agent is an isocyanate curing agent, and one or more diluents selected from toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate are selected.

[0021] Preferably, the inactive diluent or the active diluent is selected.

[0022] The present invention adopts a high-speed centrifugal production method, which allows the membrane filaments and glue to always contact the bottom of the glue inlet fixture under the effect of centrifugal action, so that the glue and the membrane pore ends are always in a close contact state, and the centrifugal time also ensures that the glue covers all gaps between the membrane filaments. Therefore, polyurethane can completely seal the membrane pore ends, improving the yield of the finished product.

[0023] The horizontal centrifugal platform of the present invention is equipped with multiple sets of fixed slots, which can simultaneously perform end sealing of multiple membrane components, greatly improving production efficiency.

[0024] The functional design of the membrane tube, the glue inlet fixture, the glue dispenser, and the horizontal centrifugal platform of the present invention is relatively simple, so the construction difficulty is lower, and the production cost is reduced.

[0025] The glue dispenser of the present invention completely empties the liquid in the dispenser through a pressurizing device, thereby greatly increasing the service life of the dispenser.

[0026] In summary, the advantages of the present invention are: 1. During centrifugation, the glue and the membrane pores are always in close contact, which can ensure that the polyurethane completely seals the membrane pores. At the same time, higher sealing efficiency and increased centrifugal speed can minimize the bubbles generated during polyurethane curing, thereby avoiding the possibility of leakage in the finished product and improving the appearance of the finished product. Improve the yield of the finished product. 2. The multiple sets of separate annular slots and glue dispensers on the centrifugal platform can cast multiple membrane components at the same time, which can greatly improve production efficiency. 3. The supporting equipment of the present invention is simple in design and easier to build, thus reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an exploded diagram of the product process. Figure 2 It is a schematic side section diagram of the membrane shell.

[0028] Figure 3 It is a side cross-sectional schematic diagram of the glue inlet mold.

[0029] Figure 4 It is a top view schematic diagram of the glue inlet mold.

[0030] Figure 5 is a top view schematic diagram of a glue dispenser.

[0031] Figure 6 is a side cross-sectional schematic diagram of a glue dispenser.

[0032] Figure 7 Schematic diagram of a centrifugal platform from top view.

[0033] Figure 8 It is a schematic diagram of the main view of the separated annular slot.

[0034] In the following figure: 1-raw water inlet hole, 2-membrane shell positioning block, 3-fixed ring, 4-glue inlet pipe A, 5-fixed groove, 6-glue flow channel, 7-stop block, 8-glue leakage hole, 9-positioning ring, 10-sealed cover, 11-glue pipeline, 12-nitrogen pipeline, 13-glue dispenser shell, 14-hemispherical container, 15-glue inlet pipe B, 16-female stop, 17-annular slot movable side, 18-annular slot positioning groove, 19-movable side rotating shaft, 20-movable side neodymium magnet, 21-centrifugal platform positioning column, 22-annular slot fixed side, 23-rotating shaft fixed base, 24-rubidium magnet fixed base. DETAILED DESCRIPTION

[0035] The following is through the attached Figure 1-8 The technical features and application advantages of the present invention are further described in detail in combination with specific implementation methods.

[0036] Example 1: Reference Figure 2-Figure 8 , a set of hollow fiber membrane casting equipment, the membrane bundle is loaded into Figure 2 The membrane shell protrudes a small amount from the bottom of the membrane shell, and then Figure 3-4The glue inlet fixture shown in the figure is fixed to the bottom of the membrane shell, 3-fixed circular ring is combined with 5-fixed groove, then 2-membrane shell positioning block is combined with 18-annular card slot positioning groove, then 20-movable side neodymium magnet is inserted into 24-neodymium magnet fixed base, then 15-glue inlet pipe B is inserted into 4-glue inlet pipe A; 21-centrifugal platform positioning column is inserted into 13-positioning ring, and the glue distributor is installed, then 10-sealed cover is covered on 16-female stop, a certain amount of glue is poured from 11-glue liquid pipeline, the centrifugal platform is started to rotate, and nitrogen is slowly poured from 12-nitrogen pipeline. The glue begins to gather in 14-hemispherical container and flows down from 8-glue leakage hole into the membrane shell.

[0037] The edge of the sealing cover is Teflon-plated.

[0038] Embodiment 2: According to the equipment description of the ultrafiltration membrane assembly casting process in Example 1, the following implementation steps are specifically included: (1) The hollow fiber membrane is folded into a bundle and the membrane hole ends are bundled. The membrane filaments are first cut neatly using a sealing machine, and then the holes are sealed at high temperature to obtain a semi-finished membrane bundle. (2) Place the semi-finished membrane filament bundle in the membrane shell, with the membrane hole end protruding out of the membrane shell. The protruding length needs to just touch the bottom of the glue inlet jig. Then press the glue inlet jig toward the bottom of the membrane tube until the annular groove inside the jig cooperates with the annular protrusion on the membrane tube, and fix the jig to the bottom of the membrane tube. (3) Inject the polyurethane resin component A and the isocyanate curing agent component B into two constant temperature stirring tanks respectively, and continue stirring at 20-30°C to ensure that the components are uniform and at a constant temperature. (4) Pour a certain ratio of A / B components into the same stirring tank, stir at 25-30°C, stop stirring after 3 minutes, start the vacuum degassing device until the bubbles disappear, and prepare the end-capping glue solution for use. (5) Match the square positioning block on the membrane shell with the square groove inside the annular groove, so that the membrane shell lies flat on the annular groove of the horizontal centrifugal platform, with the glue inlet fixture facing outward, and rotate the movable side C of the annular groove until the magnet is completely immersed in the funnel-shaped groove on the fixed side. Then position the glue dispenser according to the positioning column, insert the glue inlet pipe B into the glue inlet pipe A, and press it to the bottom. (6) After fixing the membrane tube, put the airtight cover connected to the fluid pipeline on the glue dispenser, and then pour the glue into the glue dispenser through the flow channel. After pouring the glue, slowly introduce nitrogen, and then start the centrifugal platform with a speed of 500-1000rpm. Stop after centrifugation for 15-20 minutes and let it stand for 30-60 minutes to wait for the curing degree to reach the standard. (7) Cut off the excess resin at the bottom of the membrane shell together with the glue inlet tool to expose the membrane pores, leaving the membrane pores open to obtain the liquid outlet end of the membrane assembly.

[0039] In step (1), the sealing temperature is 300-400°C and the sealing time is 5-10s.

[0040] In step (2), since the diameter difference between the annular groove inside the glue inlet mold and the annular protrusion on the membrane tube is small, the glue inlet mold can be effectively avoided from falling off during centrifugation and the glue liquid can be prevented from splashing.

[0041] In step (3), the weight ratio of the polyurethane resin component A to the curing agent component B is 100:90.

[0042] In step (3), the diluent is selected from small molecule epoxy resin.

[0043] In step (3), the curing agent is mainly HDI and HMDI mixed in a ratio of 50:40.

[0044] In step (3), the weight ratio of the diluent to component A is 100:3.

[0045] In step (6), the centrifugal platform speed is 800 rpm, the centrifugal time is 15 minutes, and the cutting is performed after standing for 40 minutes.

[0046] The purpose of the embodiments listed above is only to explain the usefulness of the present invention in more detail, and it is not to limit the scope of application of the present invention. For technicians in the relevant fields, various changes or modifications can be made on the basis of this invention, but all equivalent modifications and improvements should be included in the protection scope of the present invention.

Claims

1. A casting process for a hollow fiber membrane module, characterized in that The membrane bundle is placed in a membrane shell, and the membrane bundle is characterized in that: after the membrane bundle is folded in half, the membrane hole end is tied and fixed, the membrane hole end of the membrane bundle is heated and sealed with a sealing machine, and a glue inlet fixture is installed at the membrane hole end after sealing. The glue inlet fixture is characterized in that: an annular groove is provided on the inner wall of the glue inlet fixture, and a snowflake-shaped flow channel is provided at the bottom. The membrane hole end of the membrane bundle is tightly attached to the bottom of the glue inlet fixture, and a glue inlet pipe A is provided outward along the flow channel, and the inner diameter of the glue inlet fixture is slightly larger than the outer diameter of the membrane shell. After fixing the glue inlet jig, fix the membrane shell with the membrane bundle on the separate annular groove on the horizontal centrifugal platform. The annular groove is characterized in that the inner diameter of the groove is slightly larger than the outer diameter of the membrane shell. Then, insert the glue inlet pipe of the glue dispenser into the glue inlet jig. The glue dispenser is characterized in that four glue inlet pipes B extend from the four corners, and the outer diameter of the glue inlet pipe B is equivalent to the inner diameter of the glue inlet pipe A. The glue dispenser is fixed by four positioning columns on the horizontal centrifugal platform. Then, the resin is poured in and centrifuged, and then it is left to stand for a period of time to be completely cured. The excess resin at the membrane hole end is cut to expose the membrane hole.

2. The membrane tube according to claim 1, characterized in that The membrane tube is hollow inside, with both ends not sealed, multiple water inlet holes opened on the top of the tube, an annular protrusion near the bottom of the tube, and a square protrusion positioning block in the middle of the membrane tube.

3. The glue inlet mold according to claim 1, characterized in that An annular groove is provided on the inner wall, a snowflake-shaped glue flow channel is provided at the bottom, and a glue inlet short tube A extends along the flow channel to the outside of the mold, and the annular groove is slightly smaller than the outer diameter of the annular protrusion on the above-mentioned membrane tube.

4. The glue dispenser according to claim 1, characterized in that The overall shape is a cross, with a round hole on the top, a sealed cover installed on the round hole, and downward hemispherical containers are provided on the four corners of the jig. A rubber inlet pipe B extends from the lower end of the container. The outer diameter of the rubber outlet pipe B is equivalent to the inner diameter of the above-mentioned rubber inlet pipe A. Positioning rings are provided at the four corners of the distribution jig.

5. According to the sealed cover described in claim 4, two interfaces are provided on the cover, and the two interfaces are respectively connected to two fluid pipelines, one pipeline is used to transmit glue liquid, and the other pipeline is used to transmit nitrogen.

6. The horizontal centrifugal platform according to claim 1, characterized in that The center of the platform is hollowed out with an annular transmission structure, and twelve separate annular slots are provided along the four symmetrical directions of the center circle, with three slots in each direction, and the inner diameter of the slot is slightly larger than the outer diameter of the membrane tube.

7. The positioning column according to claim 1, characterized in that ,The four positioning columns are symmetrically distributed around the center circle of the centrifugal platform, and their outer diameters are equivalent to the positioning ring on the glue dispenser.

8. The split annular slot according to claim 5, characterized in that The card slot is divided into a movable side C and a fixed side D. A single-axis rotating structure is provided at one end of the movable side, and a cylindrical neodymium magnet is installed at the other end. A square groove is provided inside the fixed side, and the bottom is screwed on the centrifugal platform. A cylindrical groove is provided at the corresponding position of one end of the fixed side.

9. The fixed side square groove according to claim 6, characterized in that : The size of the groove is equivalent to the square raised positioning block on the outer wall of the membrane tube, and there is only one slot with a square groove in each direction.

10. The hollow fiber membrane filling process according to any one of claims 1 to 9, characterized in that : The following steps are involved: (1) Folding the hollow fiber membrane into a bundle, bundling the membrane hole ends, using a sealing machine to cut the membrane filaments neatly, and then sealing the holes at high temperature to obtain a semi-finished membrane bundle; (2) Place the semi-finished membrane bundle in the membrane shell, with the membrane hole end protruding out of the membrane shell. The protruding length needs to just touch the bottom of the glue inlet jig. Then press the glue inlet jig toward the bottom of the membrane tube until the annular groove inside the jig matches the annular protrusion on the membrane tube, and fix the jig to the bottom of the membrane tube. (3) Inject the polyurethane resin component A and the isocyanate curing agent component B into two constant temperature stirring tanks respectively, and continue stirring at 20-30°C to ensure that the components are uniform and at a constant temperature; (4) Pour a certain proportion of A / B components into the same stirring tank, stir at 25-30°C, stop stirring after 3 minutes, start the vacuum degassing device until the bubbles disappear, and prepare the glue solution for use; (5) Match the square positioning block on the membrane shell with the square groove inside the annular groove, so that the membrane shell lies flat on the annular groove of the horizontal centrifugal platform, with the glue inlet fixture facing outward, and rotate the movable side C of the annular groove until the magnet is completely immersed in the funnel-shaped groove on the fixed side, then position the glue dispenser according to the positioning column, insert the glue inlet pipe B into the glue inlet pipe A, and press it to the bottom; (6) After fixing the membrane tube, put the airtight cover connected to the fluid pipeline on the glue dispenser, and then pour the glue into the glue dispenser through the flow channel. After pouring the glue, slowly introduce nitrogen, and then start the centrifugal platform at a speed of 500-1000rpm. Centrifuge for 15-20 minutes and then stop. Let it stand for 30-60 minutes and wait for the curing degree to reach the standard; (7) Cut off the excess resin at the bottom of the membrane shell together with the glue inlet tool to expose the membrane pores, leaving the membrane pores open to obtain the liquid outlet end of the membrane assembly.

11. The filling process according to claim 8, characterized in that The polyurethane glue used in step (3) is a room temperature curing glue.

12. According to the filling process described in claim 8, the component A / B used in step (3) is characterized by being composed of a composite modified polyurethane component A and an isocyanate curing agent component B mixed in a weight ratio of 100:80-100, wherein the components A and B are respectively composed of the following raw materials: Polyurethane potting compound component A: Polyurethane: 85%-100%; Active diluent: 0-10%; Isocyanate curing agent component B: Isocyanate curing agent: 90%-100%; Functional additives: 0-10%; In addition, the above polyurethane potting glue has the following characteristics after mixing: at room temperature 25°C, after the A / B components are evenly mixed, the viscosity is 400-700cps, and the hardness after curing is 90-99 Shore A.

13. The curing agent component B according to claim 11, characterized in that : A mixture of one or more compounds selected from isocyanate curing agents, polyamides, aliphatic diols, and phenols in any proportion.

14. The diluent according to claim 11, characterized in that :Choose an inactive diluent or an active diluent.

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