Manufacturing method of flexible tubular membrane

Abstract

The invention discloses a manufacturing method of a flexible tubular membrane, which reliably improves the welding stability and further improves the use stability of the flexible tubular membrane. Two sets of ultrasonic welding heads are arranged on the peripheral area of a center guide rod in advance, and the method comprises the following steps that S1, the center guide rod is wrapped with a strip-shaped filter screen through a material conveying device; s2, covering the periphery of the central guide rod with the strip-shaped filter screen to form an overlapped part; s3, the two sets of ultrasonic welding heads are pressed on the areas on the two sides of the width position of the overlapped part through pressure, the width pressing areas, corresponding to the two ultrasonic welding heads, of the same overlapped part are not overlapped, and a gap is reserved; and S4, the two sets of ultrasonic welding heads are kept still, the overlapped parts are linearly output along with the formed flexible tubular membrane, the overlapped parts sequentially or simultaneously pass through the mutual pressing positions of the two sets of ultrasonic welding heads and the center guide rod, and after contact, the overlapped parts form two parallel welding seams due to ultrasonic welding high-speed friction.

Description

Technical Field

[0001] The invention relates to the technical field of tubular membrane production, in particular to a method for producing a flexible tubular membrane. Background Art

[0002] Ultrasonic welding is a common process in the manufacture of tubular ultrafiltration membranes. During ultrasonic welding, the ultrasonic generator generates high-frequency electrical signals, which are converted into high-frequency mechanical vibrations through the transducer. These vibrations are transmitted to the welding head through the horn. The welding head is in direct contact with the material to be welded, concentrating the vibration energy in the welding area.

[0003] The ultrasonic welding process starts with cleaning and positioning. After the surface of the material to be welded is cleaned and fixed, the ultrasonic energy is transmitted to the welding head through the transducer and the horn. The welding head concentrates the mechanical vibration energy on the contact surface, generates friction heat through high-frequency vibration, and melts the contact surface. In this process, the welding head applies appropriate pressure to make the molten materials fully contact and combine. After stopping the vibration, the pressure is maintained for a period of time, and the molten material is cooled and solidified to form a high-strength welded joint. The whole process ensures the efficient and reliable connection between the tubular membrane and the pipeline.

[0004] In the process of tubular membrane welding in the prior art, the core operating parameters include: welding frequency, energy, weld width, welding pressure, cooling after welding, welding speed, etc. Generally speaking, the yield of ultrasonic welding can reach about 95%. Such a yield is already a very high level for general production. However, for membrane filtration systems, especially tubular systems, under normal conditions, a columnar membrane contains hundreds of tubular membranes. As long as one is damaged, the entire columnar membrane system will shut down.

[0005] The existing flexible tubular membrane is welded by ultrasonic welding with a single welding head. The specific manufacturing method is shown in FIG. Figure 1 and Figure 2 , the specific manufacturing process is as follows:

[0006] S1, the strip filter is wrapped around the central guide rod through the feeder;

[0007] S2, the strip filter is wrapped around the outer periphery of the central guide rod to form an overlapping part;

[0008] S3, a single ultrasonic horn is pressed against the overlapping portion;

[0009] S4. The ultrasonic welding head remains stationary. As the center guide rod moves, the overlapping parts sequentially pass through the position where the welding head and the center guide rod press against each other. After contact, the overlapping parts form a weld due to the high-speed friction of ultrasonic welding.

[0010] The length of flexible tubular membranes that need to be welded is relatively long. Considering that the materials commonly used in flexible tubular membranes are thinner, have a wider melting point range, and weaker material strength than traditional tubular ultrafiltration membranes, ultrasonic welding is more difficult. When the weld is kept at a larger width, it is easy to cause over-welding (referring to the local excessive welding energy, causing the material to melt and burn through) or leaking welding (caused by low energy, insufficient welding strength, false welding or desoldering).

[0011] Therefore, it is urgent to develop a manufacturing method for a flexible tubular membrane, so as to reliably improve the welding stability, and then improve the use stability of the flexible tubular membrane. Summary of the invention

[0012] In view of the above problems, the present invention provides a method for manufacturing a flexible tubular membrane, which can reliably improve welding stability and further improve the use stability of the flexible tubular membrane.

[0013] A method for manufacturing a flexible tubular membrane, characterized in that two groups of ultrasonic horns are pre-arranged on the peripheral area of ​​a central guide rod, and comprises the following steps:

[0014] S1, the strip filter is wrapped around the central guide rod through the feeder;

[0015] S2, the strip filter is wrapped around the outer periphery of the central guide rod to form an overlapping part, and the width of the overlapping part is 1.5 to 13 mm;

[0016] S3, the two sets of ultrasonic welding heads are pressed on the two side areas of the width position of the overlapping part, and the width pressing areas of the same overlapping part corresponding to the two ultrasonic welding heads do not overlap and there is a gap between them;

[0017] S4. The two sets of ultrasonic welding heads remain stationary, and the overlapping parts follow the linear output of the flexible tubular membrane that has been formed at the rear end. The overlapping parts pass through the position where the two sets of ultrasonic welding heads and the central guide rod press each other sequentially or simultaneously. After contact, the overlapping parts form two parallel welds due to the high-speed friction of ultrasonic welding.

[0018] It is further characterized by:

[0019] The preferred width of the overlapping portion in step S2 is 1.5 to 5 mm;

[0020] The two sets of ultrasonic welding heads are the same ultrasonic welding heads, and the pressures applied by the two sets of ultrasonic welding heads on the filter screen surface are the same;

[0021] The weld width formed by each set of ultrasonic welding heads is 1 to 4 mm, preferably 1.5 to 3 mm, and more preferably 2 mm ± 10%;

[0022] The spacing between the two sets of welds is 0.5 to 5 mm, and the preferred spacing is 1 to 2 mm;

[0023] The linear output of the formed flexible tubular film at the rear end is driven by a servo winder for linear output;

[0024] In step S3, the two sets of ultrasonic welding heads are forced to move perpendicular to the outer periphery of the central guide rod at the corresponding position and pressed to different areas of the width position of the overlapping part, ensuring that the pressing force is perpendicular to the corresponding position of the outer periphery of the central guide rod, so that the subsequent weld is stable and reliable;

[0025] When the strip filter is wrapped around the central guide rod, the central guide rod rotates clockwise or counterclockwise at a preset speed. In step S4, the ultrasonic welding head remains stationary. With the rotation of the central guide rod and the linear output of the flexible tubular membrane formed at the rear end, the overlapping parts finally form two parallel welds, each of which is a spiral structure.

[0026] When the strip filter is wrapped around the central guide rod, the two sets of ultrasonic welding heads are located at the same position in the length direction of the central guide rod and arranged on both sides of the same overlapping part; or the two sets of welding heads are staggered in the length direction of the central guide rod;

[0027] When the strip filter is longitudinally wrapped around the central guide rod, the central guide rod does not rotate. In step S4, the ultrasonic welding head remains stationary. As the flexible tubular membrane formed at the rear end is output in a straight line, the overlapping parts eventually form two parallel welds, each of which is a straight line structure.

[0028] When the strip filter is longitudinally wrapped around the central guide rod, the two sets of ultrasonic welding heads are located at the same position in the length direction of the central guide rod and arranged on both sides of the same overlapping part; or the two sets of welding heads are staggered in the length direction of the central guide rod.

[0029] After adopting the above technical solution, the yield rate of a single weld is 95%, and the comprehensive yield rate of two welds reaches 99.75%, which reliably improves the welding stability and further improves the use stability of the flexible tubular membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The first method for manufacturing a flexible tubular membrane in the prior art;

[0031] Figure 2 The second method for manufacturing a flexible tubular membrane in the prior art;

[0032] Figure 3 It is a schematic diagram of a method for manufacturing a flexible tubular membrane according to specific embodiments 1 and 2 of the present invention;

[0033] Figure 4 It is a schematic diagram of a method for manufacturing a flexible tubular membrane according to a third specific embodiment of the present invention;

[0034] The names corresponding to the serial numbers in the figure are as follows:

[0035] Central guide rod 10, filter screen 20, overlapping portion 21;

[0036] First welding head 1, second welding head 2, first welding seam 3, second welding seam 4. DETAILED DESCRIPTION

[0037] A method for manufacturing a flexible tubular membrane, see Figure 3 and Figure 4 , two groups of ultrasonic welding heads are arranged in advance on the peripheral area of ​​the central guide rod 10, the two groups of ultrasonic welding heads are specifically a first welding head 1 and a second welding head 2, which includes the following steps:

[0038] S1, the strip filter 20 is covered on the central guide rod 10 through the feeder;

[0039] S2, the strip filter 20 is wrapped around the outer periphery of the central guide rod 10 to form an overlapping portion, and the width of the overlapping portion 21 is 1.5-13 mm;

[0040] S3, the first welding head 1 and the second welding head 2 are pressed on the two side areas of the width position of the overlapping part 21, and the width pressing areas of the first welding head 1 and the second welding head 2 corresponding to the same overlapping part 21 do not overlap and leave a gap;

[0041] S4, the first welding head 1 and the second welding head 2 remain stationary, and the overlapping part 21 follows the linear output of the flexible tubular membrane that has been formed at the rear end. The overlapping part 21 passes through the mutual pressure positions of the first welding head 1, the second welding head 2 and the center guide rod 10 sequentially or simultaneously. After contact, the overlapping part 21 forms two parallel welds due to the high-speed friction of ultrasonic welding. The two welds are specifically the first weld 3 and the second weld 4.

[0042] In specific implementation: the first welding head 1 and the second welding head 2 are the same ultrasonic welding heads, and the pressure applied by the first welding head 1 and the second welding head 2 to the surface of the filter screen 20 is the same; the width of the weld formed by the first welding head 1 and the second welding head 2 is 1 to 4 mm; the spacing between the first welding seam 3 and the second welding seam 4 is 0.5 to 5 mm;

[0043] In step S3, the two sets of ultrasonic welding heads are forced to move perpendicular to the outer periphery of the central guide rod at the corresponding position and pressed to different areas of the width position of the overlapping part, ensuring that the pressing force is perpendicular to the corresponding position of the outer periphery of the central guide rod, so that the subsequent weld is stable and reliable;

[0044] The linear output of the formed flexible tubular film at the rear end is driven by a servo winder for linear output.

[0045] In the first specific embodiment, the diameter of the central guide rod is 15 mm, the filter screen 20 is made of nylon polymer material and has a strip structure with a width of 30 mm; a double-weld head ultrasonic welding machine is used, and the two weld heads are staggered in the length direction of the weld, the first weld head is aligned with the left side of the overlapping part and the left side of the central guide rod located in the upper area, and the second weld head is aligned with the right side of the overlapping part and the right side of the central guide rod located in the lower area;

[0046] S1. The central guide rod rotates clockwise, and the strip filter 20 is wrapped around the central guide rod 10 through the feeder; the winding angle (the acute angle formed by the film and the metal conduit) is 60 degrees;

[0047] S2, the strip filter 20 is wrapped around the outer periphery of the central guide rod 10 to form an overlapping portion, and the width of the overlapping portion 21 is 6 mm;

[0048] S3, the first welding head 1 and the second welding head 2 are pressed on the two side areas of the width position of the overlapping part 21, and the width pressing areas of the first welding head 1 and the second welding head 2 corresponding to the same overlapping part 21 do not overlap and leave a gap;

[0049] S4, the first welding head 1 and the second welding head 2 remain stationary, turn on the low-temperature cooling device, set the temperature to 25 degrees Celsius, set the frequency of the first welding head 1 and the second welding head 2 to 35Hz, the welding energy to 350KJ, the welding pressure to 0.4MPa, and the welding speed to 1500mm / min, turn on the ultrasonic welder for welding, and as the center guide rod 10 rotates, the overlapping part 21 passes through the position where the first welding head 1, the second welding head 2 and the center guide rod 10 press against each other in sequence along the center guide tube. After contact, the overlapping part 21 forms two parallel welds due to the high-speed friction of ultrasonic welding. The two welds are specifically the first weld 3 and the second weld 4, and each weld is a spiral structure.

[0050] In the first specific embodiment, after the machine has been running for 10 minutes and is stable, the weld width is measured to be 2 mm ± 0.1 mm, and the width of the interval between the welds is 2 mm ± 0.2 mm.

[0051] Specific Example 1: Weld 200 meters of flexible tubular membrane, and evenly sample and test the breaking strength of 400 welds. The test method is: use an electronic tensile gauge, fix it at a vertical distance of 20 mm above and below the weld, apply vertical tension to the weld when the weld is horizontal, and record the tension when both welds are torn. Good welding is defined as a weld breaking strength > 80N. The test found that there was 1 sample with a breaking strength < 80N, and the yield rate was 99.75%.

[0052] Comparative Example 1: Under the same operating parameters, a single welding head was used for welding, and the filter mesh was sampled so that the overlap width was 2.5mm and the weld width was 2mm±0.1mm. Welding was 200 meters, and 400 welds were sampled for testing. The breaking strength was defined as the tensile force when a single weld was torn. It was found that the breaking strength was <80N for 18 samples, accounting for 95.5%.

[0053] In the second specific embodiment, the diameter of the central guide rod is 15 mm, the filter screen 20 is made of nylon polymer material and has a strip structure with a width of 20 mm; a double-weld head ultrasonic welding machine is used, and the two weld heads are staggered in the length direction of the weld, the first weld head is aligned with the left side of the overlapping part and the left side of the central guide rod located in the upper area, and the second weld head is aligned with the right side of the overlapping part and the right side of the central guide rod located in the lower area;

[0054] S1. The central guide rod rotates clockwise, and the strip filter 20 is wrapped around the central guide rod 10 through the feeder; the winding angle (the acute angle formed by the film and the metal conduit) is 30 degrees;

[0055] S2, the strip filter 20 is wrapped around the outer periphery of the central guide rod 10 to form an overlapping portion, and the width of the overlapping portion 21 is 5 mm;

[0056] S3, the first welding head 1 and the second welding head 2 are pressed on the two side areas of the width position of the overlapping part 21, and the width pressing areas of the first welding head 1 and the second welding head 2 corresponding to the same overlapping part 21 do not overlap and leave a gap;

[0057] S4, the first welding head 1 and the second welding head 2 remain stationary, turn on the low-temperature cooling device, set the temperature to 25 degrees Celsius, set the frequency of the first welding head 1 and the second welding head 2 to 35Hz, the welding energy to 350KJ, the welding pressure to 0.4MPa, and the welding speed to 1500mm / min, turn on the ultrasonic welder for welding, and as the center guide rod 10 rotates, the overlapping part 21 passes through the position where the first welding head 1, the second welding head 2 and the center guide rod 10 press against each other in sequence along the center guide tube. After contact, the overlapping part 21 forms two parallel welds due to the high-speed friction of ultrasonic welding. The two welds are specifically the first weld 3 and the second weld 4, and each weld is a spiral structure.

[0058] In the second specific embodiment, after the machine has been running for 10 minutes and is stable, the weld width is measured to be 2 mm ± 0.1 mm, and the width of the interval between the welds is 1 mm ± 0.2 mm.

[0059] Specific Example 2: Weld 100 meters of flexible tubular membrane, and evenly sample and test the breaking strength of 100 welds. The test method is: use an electronic tensile gauge, fix it at a vertical distance of 20 mm above and below the weld, apply vertical tension to the weld when the weld is horizontal, and record the tension when both welds are torn. Good welding is defined as a weld breaking strength > 80N. The test found that there were 0 samples with a breaking strength < 80N, and the yield rate was 100%.

[0060] Comparative Example 2: Under the same operating parameters, a single welding head was used for welding, and the filter mesh was sampled so that the overlap width was 2.5mm and the weld width was 2mm±0.1mm. Welding was 100 meters, and 100 welds were sampled for testing. The breaking strength was defined as the tensile force when a single weld was torn. It was found that the breaking strength was <80N for 6 samples, accounting for 94%.

[0061] In the specific embodiment 3, the diameter of the central guide rod is 15 mm, the filter screen 20 is made of nylon polymer material and has a strip structure with a width of 20 mm; a double-weld head ultrasonic welding machine is used, and the two weld heads are arranged on both sides of the longitudinal direction of the weld;

[0062] S1, the strip filter 20 is longitudinally wrapped on the central guide rod 10 through the feeder;

[0063] S2, the strip filter 20 is longitudinally wrapped around the outer periphery of the central guide rod 10 to form an overlapping portion, and the width of the overlapping portion 21 is 6 mm;

[0064] S3, the first welding head 1 and the second welding head 2 are pressed on the two side areas of the width position of the overlapping part 21, and the width pressing areas of the first welding head 1 and the second welding head 2 corresponding to the same overlapping part 21 do not overlap and leave a gap;

[0065] S4, the first welding head 1 and the second welding head 2 remain stationary, turn on the low-temperature cooling device, set the temperature to 25 degrees Celsius, set the frequency of the first welding head 1 and the second welding head 2 to 35Hz, the welding energy to 350KJ, the welding pressure to 0.4MPa, and the welding speed to 1500mm / min, turn on the ultrasonic welder for welding, and as the servo winder pulls the material, the overlapping part 21 passes through the position where the first welding head 1, the second welding head 2 and the center guide rod 10 press against each other along the central conduit. After contact, the overlapping part 21 forms two parallel welds due to the high-speed friction of ultrasonic welding. The two welds are specifically the first weld 3 and the second weld 4, and each weld is a straight line structure.

[0066] In the specific embodiment 3, after the machine has been running for 10 minutes and is stable, the weld width is measured to be 2 mm ± 0.1 mm, and the width of the interval between the welds is 2 mm ± 0.2 mm.

[0067] Specific Example 3: Weld 200 meters of flexible tubular membrane, and evenly sample and test the breaking strength of 200 welds. The test method is: use an electronic tensile gauge, fix it at a vertical distance of 20 mm above and below the weld, apply vertical tension to the weld when the weld is horizontal, and record the tension when both welds are torn. Good welding is defined as a weld breaking strength > 80N. The test found that there were 0 samples with a breaking strength < 80N, and the yield rate was 100%.

[0068] Comparative case: Under the same operating parameters, a single welding head was used for welding. The filter mesh was sampled so that the overlap width was 2.5mm and the weld width was 2mm±0.1mm. Welding was 200 meters, and 200 welds were sampled for testing. The breaking strength was defined as the tensile force when a single weld was torn. It was found that the breaking strength was <80N for 10 samples, accounting for 95%.

[0069] After using two welds to produce the flexible tubular membrane, the comprehensive weld yield reaches 99.75%, which reliably improves the welding stability and further improves the use stability of the flexible tubular membrane.

[0070] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0071] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for manufacturing a flexible tubular membrane, characterized in that: Two groups of ultrasonic welding heads are arranged in advance on the peripheral area of ​​the central guide rod, which includes the following steps: S1, the strip filter is wrapped around the central guide rod through the feeder; S2, the strip filter is wrapped around the outer periphery of the central guide rod to form an overlapping part, and the width of the overlapping part is 1.5 to 13 mm; S3, the two sets of ultrasonic welding heads are pressed on the two side areas of the width position of the overlapping part, and the width pressing areas of the same overlapping part corresponding to the two ultrasonic welding heads do not overlap and there is a gap between them; S4. The two sets of ultrasonic welding heads remain stationary, and the overlapping parts follow the linear output of the flexible tubular membrane that has been formed at the rear end. The overlapping parts pass through the position where the two sets of ultrasonic welding heads and the central guide rod press each other sequentially or simultaneously. After contact, the overlapping parts form two parallel welds due to the high-speed friction of ultrasonic welding.

2. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: The two groups of ultrasonic horns are identical ultrasonic horns, and the pressures applied by the two groups of ultrasonic horns to the surface of the filter screen are identical.

3. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: The width of the weld formed by each set of ultrasonic welding heads is 1 to 4 mm.

4. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: The spacing between two sets of welds is 0.5 to 5 mm.

5. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: The linear output of the formed flexible tubular film at the rear end is driven by a servo winder for linear output.

6. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: In step S3, the two sets of ultrasonic welding heads are forced to move, perpendicular to the outer periphery of the central guide rod at the corresponding position and pressed to different areas of the width position of the overlapping part, ensuring that the pressing force is perpendicular to the corresponding position of the outer periphery of the central guide rod, so that subsequent welds are stable and reliable.

7. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: When the strip filter is wrapped around the central guide rod, the central guide rod rotates clockwise or counterclockwise at a preset speed. In step S4, the ultrasonic welding head remains stationary. With the rotation of the central guide rod and the linear output of the flexible tubular membrane formed at the rear end, the overlapping parts eventually form two parallel welds, each of which is a spiral structure.

8. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: When the strip filter is wrapped around the central guide rod, the two sets of ultrasonic welding heads are located at the same position in the length direction of the central guide rod and arranged on both sides of the same overlapping part; or the two sets of welding heads are staggered in the length direction of the central guide rod.

9. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: When the strip filter is longitudinally wrapped around the central guide rod, the central guide rod does not rotate. In step S4, the ultrasonic welding head remains stationary. As the flexible tubular membrane formed at the rear end is output in a straight line, the overlapping parts eventually form two parallel welds, each of which is a straight line structure.

10. The method for manufacturing a flexible tubular membrane according to claim 1, characterized in that: When the strip filter is longitudinally wrapped around the central guide rod, the two sets of ultrasonic welding heads are located at the same position in the length direction of the central guide rod and arranged on both sides of the same overlapping part; or the two sets of welding heads are staggered in the length direction of the central guide rod.

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