A ceramic membrane tube inner wall uniform coating device and coating method

Abstract

The application discloses a kind of ceramic membrane tube inner wall uniform coating device and coating method, belong to membrane material preparation technical field.The device integrates liquid tank (2), stirring system (3), membrane tube positioning chamber (4), servo drive system (5) and hot air system (6).Wherein servo drive system (5) is reciprocated up and down by driving liquid tank (2), realizes the lifting and speed control of membrane tube inner coating solution, liquid tank (2) is connected inside membrane tube (7) by hose (8) to keep pressure balance, and hot air system (6) realizes the rapid drying of membrane in membrane tube.The application is by the synergistic effect of "stirring-lift-drying", makes coating solution form uniform liquid film on the inner wall of membrane tube, solves the problem of uneven coating thickness, poor adhesion and low drying efficiency in traditional coating method.The device is suitable for various specifications of membrane tube, greatly improves the coating quality and production efficiency of membrane tube, and is suitable for large-scale preparation of membrane module.

Description

Technical Field

[0001] This invention relates to the field of membrane material preparation technology, and in particular to a uniform coating device and coating method for the inner wall of a ceramic membrane tube. Background Technology

[0002] With increasingly stringent environmental requirements and expanding application scenarios, the market is placing higher demands on membrane performance and manufacturing processes. This requires not only improved core performance characteristics such as separation accuracy and permeate flux, but also greener, more scalable manufacturing processes while controlling costs. Inner membrane coating is a core step in membrane fabrication, directly determining membrane performance and lifespan: the uniformity of the coating layer directly impacts separation efficiency, membrane lifespan, and permeate flux.

[0003] CN219923507U discloses a tubular membrane coating apparatus, including a scraper and a rotary conveying device. The scraper is placed inside a support tube and conforms to the side wall of the support tube. The scraper has a cavity, one end is closed, and the other end is open and connected to the external supply of casting liquid. The side wall has an outlet hole communicating with the cavity. A thickness control ring is also included. The rotary conveying device drives the support tube to rotate around its axis and advance along its length. This tubular membrane coating apparatus, due to its casting coating method, ensures the uniformity and consistency of the coating layer, but imposes stringent requirements on the roundness and concentricity of the support tube.

[0004] CN118045737A discloses a membrane tube inner wall coating device, including a base frame, a liquid supply mechanism, a storage and circulation mechanism, a pressing mechanism, and a rotating mechanism. A liquid tank is provided on the upper part of the base frame, and a liquid supply system is provided on one side of the liquid tank. The pressing mechanism and the rotating mechanism are located to the right of the liquid supply system. The pressing mechanism adjusts the height of the sealing head, and the sealing heads on both sides fix the membrane tube to the coating position. After the rotating mechanism clamps the membrane tube, the liquid in the liquid tank is sprayed through the bottom supply system. After the liquid supply is completed, the upper sealing head of the pressing mechanism opens, draining the liquid into the liquid tank. The rotating mechanism rotates the membrane tube, draining the liquid from the other end, avoiding excessively thick coating on one side due to single-sided drainage and improving the uniformity of the coating thickness. However, the liquid in the storage and circulation mechanism cannot be stirred, which can easily lead to agglomeration and sedimentation, resulting in uneven membrane layers on the inner wall of the membrane tube.

[0005] In summary, existing technologies generally suffer from the following core defects: (1) Traditional spraying and dip coating methods cannot guarantee uniform coating thickness on the inner wall, and local over-thickness or missed coating is likely to occur; (2) The coating solution is prone to uneven concentration and particle sedimentation, resulting in poor membrane adhesion and insufficient density; (3) The drying speed is slow, and it cannot efficiently adapt to single or multi-channel membrane tubes of different specifications, resulting in poor versatility; (4) The equipment has low integration and is cumbersome to operate, making it difficult to achieve continuous and large-scale production. These problems limit the large-scale preparation of high-performance membrane tubes and cannot meet the high requirements of membrane modules in environmental protection, chemical industry and other fields.

[0006] To address the shortcomings of the existing technology, this invention provides a membrane tube inner wall coating device that integrates servo drive, active stirring, lifting coating, and rapid drying, aiming to achieve uniform and controllable coating of the membrane tube inner wall, thereby improving coating quality and production efficiency. Summary of the Invention

[0007] This invention discloses a uniform coating device and method for the inner wall of a ceramic membrane tube, aiming to achieve uniform coating of the inner wall of the membrane tube and meet the needs of large-scale preparation of high-performance membrane modules. To achieve the above objective, this invention adopts the following technical solution: The technical solution of the present invention is as follows: A device for uniformly coating the inner wall of a ceramic membrane tube includes: a support, a liquid tank, a stirring system, a membrane tube positioning chamber, a servo drive system, and a hot air system.

[0008] The support includes a support platform, a high vertical support rod and a low vertical support rod. The high vertical support rod is equipped with a clamping device and a lifting rail. The clamping device is used to clamp and fix the liquid tank, and the lifting rail allows the liquid tank to move up and down along the high vertical support rod. A magnetic rotor is placed inside the liquid tank, and an outlet is set on the lower edge of one side of the liquid tank.

[0009] The stirring system is embedded in the support platform of the bracket and is located directly below the liquid tank.

[0010] The membrane tube positioning chamber is fixed to a low vertical support rod. The membrane tube positioning chamber has upper and lower chambers for fixing the membrane tube. The lower chamber of the membrane tube positioning chamber is higher than the upper edge of the feed tank. The height of the high vertical support rod is higher than the upper chamber of the membrane tube positioning chamber by the height of the feed tank, ensuring that the feed tank can deliver the coating liquid to the top of the membrane tube. The outlet of the feed tank is connected to the lower part of the lower chamber through a hose. The upper chamber of the membrane tube positioning chamber has a hollow through-structure to discharge air from the membrane tube and ensure that the coating liquid level rises smoothly.

[0011] The servo drive system is located on the support platform and is connected to the material tank for transmission.

[0012] The hot air system is located on the support platform and is connected to the upper chamber of the membrane tube positioning chamber via a hot air pipe.

[0013] The volume of the feed tank is greater than that of the membrane tube, and its upper end has an open structure.

[0014] An inclined iron mesh is provided at the outlet of the liquid tank. The angle between the iron mesh and the bottom of the liquid tank is 15-45°. This is used to filter impurities in the coating liquid and prevent the magnetic rotor from clogging the outlet.

[0015] The low vertical support rod has two long vertical grooves along its body. A slider is installed in the groove. The slider is fastened and loosened to the left and right sides of the upper chamber with screws, so as to realize the upper chamber moving up and down along the low vertical support rod to adapt to membrane tubes of different lengths.

[0016] The upper chamber, lower chamber and membrane tube contact end face are each provided with annular elastic sealing rings. After the upper chamber is pressed down, the sealing rings are squeezed and sealed with the membrane tube end face.

[0017] The servo drive system adopts closed-loop control, with a position control accuracy of ±0.01mm and an adjustable range of 5~500mm / min for the lifting and moving speed of the liquid tank.

[0018] The coating method based on the above-mentioned uniform coating device for the inner wall of ceramic membrane tube includes multiple processes such as membrane tube positioning, homogenous stirring of coating liquid, uniform speed lifting and dipping coating, and hot air in-situ drying. The specific operation steps are as follows: Step 1: Loosen the locking screw at the slider and slide the upper chamber upward along the vertical groove of the low vertical support rod; place the ceramic membrane tube to be coated into the lower chamber, slide the upper chamber downward to press the two ends of the membrane tube, tighten the screw to lock the height, and rely on the annular elastic sealing ring to complete the end sealing; pour the prepared coating solution into the material tank and put in the magnetic rotor, turn on the stirring system to stir the coating solution evenly, stirring speed 500-1500 rpm, stirring time 0.5-10 min; Step 2: Start the servo drive system and control the liquid tank to rise at a speed of 5~500mm / min. The coating liquid enters the membrane tube channel through the hose and is pulled upward. Under the lifting action, the coating liquid is evenly spread on the inner wall of the membrane tube. When the horizontal height of the bottom of the liquid tank is level with the top of the membrane tube, stop rising. After waiting for 10-600s, the servo drive system controls the liquid tank to move downward at a speed of 5~500mm / min to the starting position.

[0019] Step 3: Connect the hot air pipe to the membrane tube positioning chamber, turn on the hot air system, adjust the hot air pressure to 1.05~1.5 bar and the hot air temperature to 50~200℃, and blow into the membrane tube for 0.5~5 minutes to dry the inner surface of the membrane tube. Repeat steps 1-3 above to re-dip and dry the membrane tube until the number of coatings meets the preset requirements. Then remove the membrane tube to complete the coating process.

[0020] Compared with the prior art, the present invention has the following significant advantages: (1) Excellent coating thickness uniformity, thickness fluctuation ≤ ±3%; (2) Strong coating adhesion and high density, which can meet the use requirements under harsh working conditions; (3) Adaptable to a variety of membrane tube sizes, with strong versatility; (4) High device integration, convenient operation, and can realize continuous production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the device for uniformly coating the inner wall of the membrane tube.

[0022] Figure 2 This is a schematic diagram of the membrane tube positioning chamber.

[0023] Figure 3 This is a cross-sectional view of the membrane tube positioning chamber.

[0024] Figure 4 This is a magnified view of a portion of the upper chamber and the sliding block of the low vertical support rod groove.

[0025] 1. Support; 2. Feed tank; 3. Stirring system; 4. Membrane tube positioning chamber; 5. Servo drive system; 6. Hot air system; 7. Membrane tube; 8. Flexible hose; 9. Magnetic rotor; 10. Iron mesh; 11. Hot air duct; 12. Annular elastic sealing ring; 1A. High vertical support rod; 1B. Low vertical support rod; 4A. Upper chamber; 4B. Lower chamber; 13. Slider; 14. Screw. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0027] A device for uniformly coating the inner wall of a ceramic membrane tube includes: a support 1, a liquid tank 2, a stirring system 3, a membrane tube positioning chamber 4, a servo drive system 5, and a hot air system 6.

[0028] The support 1 includes a support platform, a high vertical support rod 1A and a low vertical support rod 1B. The high vertical support rod 1A is equipped with a clamping device and a lifting rail. The clamping device is used to clamp and fix the liquid tank 2. The lifting rail allows the liquid tank 2 to move up and down along the high vertical support rod 1A. A magnetic rotor 9 is placed inside the liquid tank 2. An outlet is provided on the lower edge of one side of the liquid tank 2.

[0029] The stirring system 3 is embedded in the support platform of the support 1 and is located directly below the liquid tank 2.

[0030] The membrane tube positioning chamber 4 is fixed to the low vertical support rod 1B. The membrane tube positioning chamber 4 has two chambers, 4A and 4B, for fixing the membrane tube 7. The lower chamber 4B of the membrane tube positioning chamber 4 is higher than the upper edge of the liquid tank 2. The height of the high vertical support rod 1A is higher than the upper chamber 4A of the membrane tube positioning chamber 4 by the height of the liquid tank 2, ensuring that the liquid tank 2 can deliver the coating liquid to the top of the membrane tube 7. The outlet of the liquid tank 2 is connected to the lower part of the lower chamber 4B through a hose 8. The upper chamber 4A of the membrane tube positioning chamber 4 is a hollow through-structure to discharge the air in the membrane tube 7, ensuring that the coating liquid level rises smoothly.

[0031] The servo drive system 5 is located on the support platform and is connected to the liquid tank 2 via a transmission.

[0032] The hot air system 6 is located on the support platform and is connected to the upper chamber 4A of the membrane tube positioning chamber 4 through the hot air pipe 11.

[0033] The volume of the feed tank 2 is greater than that of the membrane tube 7, and its upper end has an open structure.

[0034] An inclined iron mesh 10 is provided at the outlet of the liquid tank 2. The angle between the iron mesh 10 and the bottom of the liquid tank 2 is 15~45°. This is used to filter impurities in the coating liquid and prevent the magnetic rotor 9 from clogging the outlet.

[0035] The low vertical support rod 1B has two long vertical sliding grooves along its body. Each groove is equipped with a pair of sliders 13. The sliders 13 are locked or released by screws 14, thereby enabling the upper chamber 4A to move up and down along the low vertical support rod 1B to accommodate membrane tubes 7 of different lengths.

[0036] The upper chamber 4A, lower chamber 4B, and membrane tube 7 are all provided with annular elastic sealing rings 12 at their contact surfaces.

[0037] The position control accuracy of the servo drive system 5 is ±0.01mm, and the adjustable range of the lifting and moving speed of the liquid tank 2 is 5~500mm / min. Example 1

[0038] This embodiment takes the coating of the inner wall of a single-channel ceramic membrane tube as an example, and the specific steps are as follows: 1. Loosen the locking screws 14 on both sides of the slider 13, and slide the upper chamber 4A upward along the vertical groove of the low vertical support rod 1B; place the single-channel ceramic membrane tube 7 with a length of 1500mm and an inner diameter of 40mm in the lower chamber 4B, slide the upper chamber 4A downward to press the two ends of the membrane tube, tighten the locking screws to fix the height, and complete the sealing and fixing by relying on the end face sealing ring 12.

[0039] 2. Pour the prepared coating solution into the liquid tank 2 and place the magnetic rotor 9 in it; turn on the stirring system 3 and drive the magnetic rotor 9 to rotate through magnetic coupling. Control the speed to 800 rpm and the stirring time to 5 min to make the coating solution evenly mixed.

[0040] 3. Turn on the servo drive system 5 and control the liquid tank 2 to lift upward at a speed of 50 mm / min. Under the lifting action, the coating liquid is evenly spread on the inner wall of the membrane tube 7. When the bottom of the liquid tank 2 is level with the top of the membrane tube 7, stop rising. After waiting for 30 seconds, the servo drive system 5 controls the liquid tank 2 to move downward at a speed of 50 mm / min to the starting position.

[0041] 4. Connect the hot air pipe 11 to the top of the upper chamber 4A of the membrane tube positioning, turn on the hot air system 6, adjust the hot air pressure to 1.2 bar and the hot air temperature to 100°C, and blow into the ceramic membrane tube 7 for 2 minutes to quickly dry the membrane layer on the inner wall of the membrane tube 7.

[0042] 5. Repeat steps 2 to 4 above to re-dip-coat and dry the ceramic membrane tube 7. Coat it 3 times to ensure that the membrane thickness meets the design requirements. Remove the ceramic membrane tube 7 to obtain a ceramic membrane tube 7 with a uniform inner wall coating.

[0043] Testing revealed that the ceramic membrane tube prepared in this embodiment had a uniform inner wall coating thickness with a thickness fluctuation of ±2.5%. Example 2

[0044] This embodiment takes the coating of the inner wall of a seven-channel ceramic membrane tube as an example, and the specific steps are as follows: 1. Loosen the locking screws 14 on both sides of the slider 13, and slide the upper chamber 4A upward along the vertical groove of the low vertical support rod 1B; place the seven-channel ceramic membrane tube 7 with a length of 200mm and an inner diameter of 10mm in the lower chamber 4B, slide the upper chamber 4A downward to press the two ends of the membrane tube, tighten the locking screws to fix the height, and complete the sealing and fixing by relying on the end face sealing ring 12.

[0045] 2. Pour the coating liquid into the liquid tank 2, place the magnetic rotor 9 inside, set the stirring system 3 to 1200 rpm, and stir for 8 minutes to eliminate powder sedimentation.

[0046] 3. Turn on the servo drive system 5 and set the lifting speed to 30mm / min. Control the liquid tank 2 to rise at a uniform speed to the top of the membrane tube 7, let it stand for 120s to soak, and then fall back to the initial position at the same speed.

[0047] 4. Connect the hot air pipe 11 to the top of the upper chamber 4A of the membrane tube positioning chamber, set the hot air pressure to 1.5 bar and the hot air temperature to 120°C, and continue blowing for 3 minutes to complete the drying. Remove the ceramic membrane tube 7 to obtain a ceramic membrane tube 7 with a uniform inner wall coating.

[0048] Test results: The coating thickness on the inner wall of the membrane tube fluctuated by ±1.9%, and the coating thickness of each channel in the multi-channel system was consistent, with no localized missing coating or material accumulation defects.

Claims

1. A device for uniformly coating the inner wall of a ceramic membrane tube, characterized in that, include: Support (1), feed tank (2), stirring system (3), membrane tube positioning chamber (4), servo drive system (5), hot air system (6); The support (1) includes a support platform, a high vertical support rod (1A) and a low vertical support rod (1B). The high vertical support rod (1A) is equipped with a clamping device and a lifting rail. The clamping device is used to clamp and fix the liquid tank (2). The lifting rail allows the liquid tank (2) to move up and down along the high vertical support rod (1A). A magnetic rotor (9) is placed inside the liquid tank (2). An outlet is provided on the lower edge of one side of the liquid tank (2). The stirring system (3) is embedded in the support platform of the support (1) and is located directly below the liquid tank (2); The membrane tube positioning chamber (4) is fixed on the low vertical support rod (1B). The membrane tube positioning chamber (4) has two chambers (4A, 4B) for fixing the membrane tube (7). The lower chamber (4B) of the membrane tube positioning chamber (4) is higher than the upper edge of the liquid tank (2). The height of the high vertical support rod (1A) is higher than the upper chamber (4A) of the membrane tube positioning chamber (4) by the height of the liquid tank (2), ensuring that the liquid tank (2) delivers the coating liquid to the top of the membrane tube (7). The outlet of the liquid tank (2) is connected to the lower part of the lower chamber (4B) through the hose (8). The upper chamber (4A) of the membrane tube positioning chamber (4) is a hollow through structure, used to discharge the air in the membrane tube (7) and ensure that the coating liquid level rises smoothly. The servo drive system (5) is located on the support platform and is connected to the liquid tank (2) for transmission. The hot air system (6) is located on the support platform and is connected to the upper chamber (4A) of the membrane tube positioning chamber (4) through the hot air pipe (11).

2. The ceramic membrane tube inner wall uniform coating device according to claim 1, characterized in that: The volume of the liquid tank (2) is greater than that of the membrane tube (7), and its upper end is an open structure.

3. The ceramic membrane tube inner wall uniform coating device according to claim 1, characterized in that: An inclined iron mesh (10) is provided at the outlet of the liquid tank (2). The angle between the iron mesh (10) and the bottom of the liquid tank (2) is 15~45°. It is used to filter impurities in the coating liquid and at the same time prevent the magnetic rotor (9) from blocking the outlet.

4. The ceramic membrane tube inner wall uniform coating device according to claim 1, characterized in that: The low vertical support rod (1B) has two vertical long sliding grooves along its body. Each groove is equipped with a pair of sliders (13). The sliders (13) are locked or released by screws (14) so ​​that the upper chamber (4A) can move up and down along the low vertical support rod (1B) to adapt to membrane tubes (7) of different lengths.

5. The uniform coating device for the inner wall of a ceramic membrane tube according to claim 1, characterized in that: The upper chamber (4A), lower chamber (4B) and membrane tube (7) are all provided with annular elastic sealing rings (12) at their contact surfaces.

6. The ceramic membrane tube inner wall uniform coating device according to claim 1, characterized in that: The position control accuracy of the servo drive system (5) is ±0.01mm, and the lifting and moving speed of the liquid tank (2) is 5~500mm / min.

7. A method for coating the inner wall of a ceramic membrane tube using the uniform coating apparatus according to any one of claims 1-6, characterized in that, The details are as follows: Step 1: Loosen the locking screw (14) at the slider (13), slide the upper chamber (4A) upward along the vertical groove of the low vertical support rod (1B); put the ceramic membrane tube (7) to be coated into the lower chamber (4B), slide the upper chamber downward to press the two ends of the membrane tube, tighten the screw (14), and complete the end sealing by relying on the annular elastic sealing ring (12); fix the membrane tube (7) to be coated vertically in the membrane tube positioning chamber (4), pour the prepared coating liquid into the material tank (2) and put in the magnetic rotor (9), turn on the stirring system (3) to stir the coating liquid evenly, the stirring speed is 500-1500 rpm, and the stirring time is 0.5-10 min; Step 2: Start the servo drive system (5) and control the liquid tank (2) to rise at a speed of 5~500mm / min. The coating liquid enters the membrane tube (7) channel through the hose (8) and is pulled upward. Under the pulling action, the coating liquid is evenly spread on the inner wall of the membrane tube (7). When the horizontal height of the bottom of the liquid tank (2) is level with the top of the membrane tube (7), stop rising. After waiting for 10-600s, the servo drive system (5) controls the liquid tank (2) to move downward to the starting position at a speed of 5~500mm / min. Step 3: Connect the hot air pipe (11) to the upper chamber (4A) of the membrane tube positioning chamber (4), turn on the hot air system (6), adjust the hot air pressure to 1.05~1.5 bar and the hot air temperature to 50~200℃, and blow into the membrane tube (7) for 0.5~5 min to dry the inner surface of the membrane tube (7); Repeat steps 1-3 above to re-dip and dry the membrane tube until the number of coatings meets the preset requirements. Then remove the membrane tube to complete the coating process.

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