System for manufacturing peroxide crosslinked polyethylene pipes and support mechanism thereof

Abstract

The present application relates to the technical field of manufacturing peroxide cross-linked polyethylene pipe, and discloses a system for manufacturing peroxide cross-linked polyethylene pipe and a supporting mechanism thereof, wherein the supporting mechanism comprises a base, and a supporting roller rotatably connected to the base; a groove for supporting the pipe is arranged on the roller surface of the supporting roller; the groove surrounds a circumference of the roller surface; a plurality of recessed holes are arranged on the groove wall of the groove; the recessed holes are arranged in an array; the aperture of the recessed holes is 0.1 mm; and the density N of the recessed holes is greater than or equal to 100 per cm 2 The recessed holes are used for contacting the protective gas and forming a gas film on the groove wall of the groove. Through the structure, the pipe can be prevented from adhering to the supporting device, the production efficiency is improved, and the quality problem of the pipe is reduced.

Description

Technical Field

[0001] This invention relates to the field of manufacturing peroxide cross-linked polyethylene pipes, and in particular to a system for manufacturing peroxide cross-linked polyethylene pipes and its support structure. Background Technology

[0002] During the cross-linking reaction, the pipe is usually supported by a support roller. The support roller is in direct contact with the pipe, which can easily lead to adhesion between the pipe and the support roller. This prevents the pipe from moving smoothly on the surface of the support roller, affecting the production efficiency of the pipe and making the pipe prone to quality defects. Summary of the Invention

[0003] The purpose of this invention is to provide a system for cross-linked polyethylene pipes and its support mechanism, which can reduce the adhesion between the pipe and the support device, improve production efficiency, and reduce pipe quality problems.

[0004] To achieve the above objectives, the present invention provides a support mechanism for a peroxide cross-linked polyethylene pipe system, comprising:

[0005] Base;

[0006] A support roller, rotatably connected to the base, has grooves on its surface for supporting the pipe. These grooves surround the roller surface, and the groove walls have multiple recessed holes arranged in an array. The diameter of each recessed hole is 0.1 mm, and the density N of the recessed holes is greater than or equal to 100 holes / cm². 2 The recessed hole is used to contact the protective gas and form a gas film on the groove wall.

[0007] In some embodiments:

[0008] The groove wall is also provided with a protective coating, which includes polytetrafluoroethylene.

[0009] In some embodiments:

[0010] The protective coating also includes microcapsules with a diameter ranging from 50 to 100 μm and a wall thickness of 1 to 5 μm, and the interior of the microcapsules is filled with siloxane.

[0011] In some embodiments:

[0012] The capsule wall material of the microcapsule includes dicyclopentadiene.

[0013] In some embodiments:

[0014] The base also includes a seat body and a hydraulic support device. The hydraulic support device is disposed on both sides of the seat body. The hydraulic support device is also provided with a connecting rod. The connecting rod is connected to both sides of the support roller, and the support roller is rotatably connected to the hydraulic support device through the connecting rod.

[0015] In some embodiments:

[0016] The seat body has a receiving cavity with openings at the front and back, the support roller is disposed in the receiving cavity, and the connecting rod passes through the seat body.

[0017] In some embodiments, the support structure of the peroxide cross-linked polyethylene pipe system further includes:

[0018] A pressure sensor, which is disposed inside the support roller, is used to detect the pressure on the support roller;

[0019] The controller is electrically connected to the pressure sensor and the hydraulic support device.

[0020] This invention also provides a system for manufacturing peroxide cross-linked polyethylene pipes, comprising:

[0021] The support structure of the peroxide cross-linked polyethylene pipe system as described above;

[0022] A crosslinking furnace having a crosslinking chamber with openings at the front and back, wherein a support mechanism for the peroxide crosslinked polyethylene pipe system is disposed on at least one side of the crosslinking chamber.

[0023] In some embodiments:

[0024] The crosslinking furnace is provided with a first opening, which is used to introduce protective gas into the crosslinking chamber. The protective gas introduced through the first opening can form a spiral airflow on the pipe, and the spiral airflow forms a gas film on the groove wall.

[0025] In some embodiments:

[0026] The temperature range within the cross-linking chamber is 230℃-250℃.

[0027] This invention provides a system for peroxide cross-linked polyethylene pipes and its support structure. Compared with the prior art, its advantages are as follows:

[0028] The support mechanism of the peroxide cross-linked polyethylene pipe system of the present invention includes a base and a support roller rotatably connected to the base. The support roller is provided with a groove for supporting the pipe, and the groove wall is provided with an array of recessed holes. The recessed holes are used to form an air film on the groove wall. The air film plays an isolation role, which can reduce the direct contact between the groove wall and the pipe, reduce the adhesion of the pipe to the support device, improve production efficiency, and reduce pipe quality problems.

[0029] The peroxide cross-linked polyethylene pipe system of the present invention includes the above-described support mechanism, which can reduce the adhesion between the pipe and the support device, improve production efficiency, and reduce pipe quality problems. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the support mechanism of the peroxide cross-linked polyethylene pipe system according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the support roller structure according to an embodiment of the present invention.

[0032] Figure 3 yes Figure 2 Enlarged diagram of point A in the middle.

[0033] Figure 4 This is a schematic diagram of the crosslinking furnace and support mechanism of the peroxide crosslinked polyethylene pipe system according to an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of the structure of the pipe passing through the cross-linking cavity and the receiving cavity in an embodiment of the present invention.

[0035] In the figure, 100 is the support mechanism; 200 is the cross-linking furnace; 110 is the base; 120 is the support roller; 111 is the seat; 112 is the hydraulic support device; 113 is the connecting rod; 114 is the accommodating cavity; 115 is the second opening; 121 is the groove; 122 is the concave hole; 123 is the protective coating; 210 is the cross-linking cavity; and 220 is the first opening. Detailed Implementation

[0036] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0037] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0040] Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Please refer to Figure 1 The preferred embodiment of the present invention provides a support mechanism 100 for a peroxide cross-linked polyethylene pipe system, comprising: a base 110 and a support roller 120.

[0042] Please follow Figure 2 and Figure 3 The support roller 120 is rotatably connected to the base 110. The roller surface of the support roller 120 is provided with a groove 121 for supporting the pipe. The groove 121 surrounds the circumference of the roller surface, and the groove wall of the groove 121 is provided with a plurality of recesses 122 arranged in an array. The diameter of the recesses 122 is 0.1 mm, and the density N of the recesses 122 is greater than or equal to 100 per cm. 2 The recess 122 is used to contact the protective gas and form a gas film on the groove wall of the groove 121.

[0043] The recess 122 is used to form a gas film on the groove wall. In this embodiment, the protective gas is carbon dioxide gas. The protective gas can be formed by the airflow directly contacting the groove wall of the recess 121, or by being ejected from the recess 122. For the gas to be ejected from the recess 122, a flow channel needs to be provided inside the support roller 120, and the flow channel needs to be connected to the recess 122.

[0044] The air-supported membrane structure provides isolation, reducing direct contact between the tank wall and the pipes, and significantly lowering the risk of adhesion between the pipes and the support device. By avoiding surface damage and production interruptions caused by contact friction and adhesion, it not only improves production efficiency but also effectively reduces quality issues such as surface defects and deformation of the pipes, thereby increasing product yield and ensuring product quality stability.

[0045] The temperature of the protective gas is 40℃-60℃. It can not only form a gas film to provide protection, but also cool the pipe to a certain extent, which helps to stabilize the shape of the pipe.

[0046] The flow rate QL / min of the protective gas and the jet pressure P kPa of the concave orifice 122 satisfy the following:

[0047] P = 0.2Q + 0.5

[0048] In this embodiment, when the protective gas flow rate is 10-15 L / min and the injection pressure is 2.5-3.5 kPa, a continuous gas film can be stably formed, avoiding airflow turbulence.

[0049] To verify the above technical effects, a correlation test was set up to measure the density, pore size, and air film performance of the concave hole 122. The test data and results of the density, pore size, and air film coverage of the concave hole 122 are shown in Table 1.

[0050] The protective gas flow rate is 10 L / min, and the crosslinking temperature is 240℃.

[0051] The distribution of air film on the groove wall is recorded by a high-speed camera to obtain the air film coverage rate, so as to evaluate the air film performance.

[0052] Table 1

[0053]

[0054]

[0055] As shown in Table 1, increasing the diameter leads to accelerated gas diffusion and decreased gas film uniformity. This is especially true when the pore density is ≥100 pores / cm³. 2 When the orifice diameter is 0.1mm, the air film coverage is ≥95% and the spray pressure is stable.

[0056] In some embodiments, a protective coating 123 is also provided on the groove wall of the groove 121, the protective coating 123 comprising polytetrafluoroethylene.

[0057] Polytetrafluoroethylene (PTFE) has a low coefficient of friction, which makes the surface of the groove 121 smooth and reduces the adhesion between the groove wall and the pipe. At the same time, PTFE is non-stick, which makes it difficult for the pipe to adhere to the groove wall of the groove 121, thus reducing the adhesion between the groove wall and the pipe.

[0058] To verify the above technical effects, a comparative test was conducted on the traditional support roller without recesses and protective coatings in the prior art and the support mechanism of this embodiment.

[0059] The cross-linking furnace temperature is 240℃, the protective gas is CO2 with a flow rate of 10L / min, the pipe running speed is 2m / min, and the protective coating is a polytetrafluoroethylene coating.

[0060] Table 2 shows the experimental data and results.

[0061] Table 2

[0062] Pipe adhesion rate (times / hour) 8.2 0.3 Surface defect rate (%) 12.5 1.2 Number of production interruptions (per shift) 6 0

[0063] As shown in Table 2, the adhesion of the support mechanism in this embodiment is reduced, the surface defect rate is also smaller, which improves production efficiency and reduces quality problems of the pipe.

[0064] The protective coating 123 also includes microcapsules with a diameter ranging from 50 to 100 μm and a wall thickness of 1 to 5 μm. The interior of the microcapsules is filled with siloxane.

[0065] When the protective coating 123 is damaged, the microcapsules rupture due to friction or other means. The siloxane inside the microcapsules acts as a repair agent, exhibiting good flowability and adhesion, flowing to the damaged area of ​​the protective coating 123 to repair the coating. The siloxane can react with polytetrafluoroethylene to form chemical bonds, thus firmly adhering to the protective coating 123 and restoring the coating's anti-stick properties.

[0066] In this way, the damaged areas of the protective coating 123 can be automatically repaired, reducing the possibility of the pipe being scratched, while increasing the service life of the protective coating 123 and reducing the maintenance frequency of the support mechanism 100.

[0067] The capsule wall material of the microcapsule includes dicyclopentadiene, which melts in the temperature range of 150℃-180℃. The cross-linking reaction of the tube is usually in the range of 230℃-250℃. Therefore, the temperature of the tube can be used to rupture the microcapsule and repair the protective coating 123.

[0068] The thickness of the capsule wall is controlled within the range of 1-5 μm, the complete rupture temperature is 170-185℃, and the rupture rate is ≥90% in the 250℃ high temperature test. This ensures that the microcapsules rupture reliably at the cross-linking temperature and avoids the delay in the release of the repair agent due to excessively thick capsule walls.

[0069] To verify whether the microcapsules could rupture spontaneously, an experiment was conducted.

[0070] The capsule wall material is dicyclopentadiene (DCPD), and the core material is siloxane. Microcapsules were prepared via interfacial polymerization. The monomer concentration of DCPD was adjusted within the range of 5%-20%, and reaction times ranged from 1-4 hours to obtain samples with varying capsule wall thicknesses.

[0071] The microcapsules were frozen and fractured using a scanning electron microscope, then sputtered with gold, and cross-sectional images were taken. The capsule wall thickness was measured. At least 50 samples were measured and the average value was taken. The capsule wall thickness of these samples was measured to be 1-10 μm. The diameter of the microcapsules was measured to be 50-100 μm using a laser particle size analyzer.

[0072] The thermal response of the microcapsules was tested by differential scanning calorimetry using a TA Instruments Q200 instrument. The softening initiation temperature T of the capsule wall was obtained under conditions of a heating rate of 10℃ / min, a nitrogen atmosphere, and a temperature range of 25-300℃. onset and complete rupture temperature T peak .

[0073] The microcapsules were placed in a 250°C oven for 10 minutes, and the rupture rate was observed using an optical microscope to conduct a high-temperature rupture test.

[0074] For the test method of siloxane coverage (%):

[0075] Sample preparation: Scratches are artificially created on the surface of the protective coating, such as scratches with a length of 10 mm and a depth of 50 μm. The sample is placed in a crosslinking furnace and run for 1 hour at a crosslinking chamber temperature of 240 °C to cause the microcapsules to rupture and release siloxane.

[0076] Surface treatment: After cooling, clean the repaired area with anhydrous ethanol to remove unreacted siloxane residue.

[0077] Microscopic observation: The surface morphology of the repaired area was analyzed using scanning electron microscopy (SEM) or confocal laser microscopy. The distribution of characteristic peaks of silicon or siloxanes was detected by energy dispersive spectroscopy (EDS) or Raman spectroscopy to locate the repaired area.

[0078] Image analysis: Using image processing software such as ImageJ, the repaired area is binarized, and the percentage of the area covered by siloxane to the total scratch area is calculated using the following formula:

[0079]

[0080] For the testing method of the friction coefficient after repair:

[0081] Sample preparation: Using the same sample preparation method as the siloxane coverage test, prepare a scratched and repaired coating sample.

[0082] Friction test: A ball-disc friction tester, such as UMT TriboLab, was used with a 6mm diameter carbide ball as the grinding pair, a normal load of 5N was applied, the sliding speed was 0.1m / s, the sliding distance was 10mm, and a linear reciprocating friction test was carried out at room temperature.

[0083] Data acquisition: Record the dynamic friction coefficient curve during the friction process, and take the average value of the stable stage as the friction coefficient after repair.

[0084] Repeated validation: Each sample should be tested at least 3 times, and the arithmetic mean should be taken to ensure data reliability.

[0085] Please refer to Table 3 for the experimental data and results.

[0086] Table 3

[0087]

[0088]

[0089] As shown in Table 3, when the capsule wall thickness is ≤5.8μm, T peak The fracture rate is ≥90% at ≤185℃ and 250℃.

[0090] When the capsule wall thickness is >8μm, T peak When the temperature approaches or exceeds 200°C, the cracking rate decreases significantly (<70%).

[0091] When the capsule wall thickness is ≤5μm, the siloxane coverage is ≥85%, and the repair effect is significant.

[0092] Therefore, when the thickness of the capsule wall is controlled within the range of 1-5 μm, the rupture rate is relatively high, which facilitates the repair of the protective coating 123.

[0093] To verify the repair effect of the microcapsule on the protective coating 123, an experiment was conducted.

[0094] Control group: Polytetrafluoroethylene coating without microcapsules.

[0095] Experimental group: Polytetrafluoroethylene coating containing microcapsules (capsule wall thickness 3μm).

[0096] Test method: The coating was artificially scratched (scratch length 10mm, depth 50μm), and the coating was run in a crosslinking furnace for 1 hour (240℃). The repair effect was tested after cooling.

[0097] Please refer to Table 4 for the test results.

[0098] Table 4

[0099]

[0100]

[0101] As shown in Table 4, the siloxanes released after the microcapsule rupture can effectively repair the protective coating 123.

[0102] In some embodiments, the base 110 further includes a seat body 111 and a hydraulic support device 112. The hydraulic support device 112 is disposed on both sides of the seat body 111. The hydraulic support device 112 is also provided with a connecting rod 113. The connecting rod 113 is connected to both sides of the support roller 120, and the support roller 120 is rotatably connected to the hydraulic support device 112 through the connecting rod 113.

[0103] The hydraulic support device 112 can adjust the support force of the support roller 120. Through this structure, the support roller 120 can stably support the pipe.

[0104] The seat 111 has a receiving cavity 114 with front and rear openings, the support roller 120 is disposed in the receiving cavity 114, and the connecting rod 113 passes through the seat 111.

[0105] The pipe passes through the receiving cavity 114 and is supported by the support roller 120. The seat body 111 is also provided with a clearance channel, through which the connecting rod 113 passes through the clearance channel and passes through the seat body 111, so that one end of the connecting rod 113 is outside the receiving cavity 114 and connected to the hydraulic support device 112, and the other end of the connecting rod 113 is inside the receiving cavity 114 and connected to the support roller 120.

[0106] The support mechanism 100 of the peroxide cross-linked polyethylene pipe system also includes: a pressure sensor and a controller. The pressure sensor is installed inside the support roller 120 and is used to detect the pressure on the support roller 120. The controller is connected to the pressure sensor and the hydraulic support device 112.

[0107] The pressure sensor can detect the pressure exerted by the pipe on the support roller 120. The pressure sensor can be installed at the contact point between the support roller 120 and the pipe, or inside the support roller 120 near the contact point. The pressure sensor detects the real-time pressure and feeds it back to the controller, which can convert it into the amount of pipe sag and control the hydraulic support device 112 to adjust the support force to prevent the pipe from collapsing due to its own weight.

[0108] Please refer to Figure 4 and Figure 5 This embodiment also provides a system for manufacturing peroxide cross-linked polyethylene pipes, including: the support mechanism 100 and the cross-linking furnace 200 described above. The cross-linking furnace 200 has a cross-linking cavity 210 with front and rear openings, and the support mechanism 100 of the peroxide cross-linked polyethylene pipe system is disposed on at least one side of the cross-linking cavity 210.

[0109] In this embodiment, multiple cross-linking furnaces 200 are configured, and each cross-linking furnace 200 has a support mechanism 100 on both sides to provide better support for the pipe. In addition, the receiving cavity 114 of the support mechanism 100 is connected to the cross-linking cavity 210.

[0110] The crosslinking furnace 200 is provided with a first opening 220, which is used to introduce protective gas into the crosslinking chamber 210. The protective gas introduced into the first opening 220 can form a spiral airflow on the pipe, and the spiral airflow forms a gas film on the groove wall of the groove 121.

[0111] The protective gas is carbon dioxide. The protective gas blown into the crosslinking chamber 210 from the first opening 220 forms a spiral airflow on the pipe surface. This spiral airflow continuously washes over the pipe surface, carrying away any oxygen present and preventing incomplete decomposition or other side reactions of the peroxides during the crosslinking process due to oxygen interference. Furthermore, it helps to uniformly measure the temperature of the pipe surface, making the crosslinking reaction more uniform. In addition, the spiral airflow forms an air film on the surface of the support roller 120 as it passes through the groove wall.

[0112] Preferably, the first opening 220 can be tilted at an angle between 30° and 45°, allowing the airflow to form a spiral motion along the pipe axis.

[0113] The protective gas flow rate ranges from 5 m / s to 8 m / s.

[0114] To verify the performance of the air film formed by the spiral airflow on the surface of the tank wall, an experiment was conducted.

[0115] A 50mm pipe was used, the protective gas flow rate was 6m / s, the protective gas flow angle was 40°, the temperature inside the cross-linking chamber 210 was 240℃, and the spiral gas pitch and gas film thickness were detected by a particle image velocimeter (PIV) and an infrared thermal imager.

[0116] Spiral airflow pitch (mm): the ratio to the pipe diameter.

[0117] Air film thickness (mm): The temperature gradient is detected by the infrared thermal imager, and the air film thickness is deduced from it.

[0118] Please refer to Table 5 for the test results.

[0119] Table 5

[0120] Crosslinking cavity inlet 75±2 0.08±0.01 ±2.5 support roller groove 75±3 0.10±0.02 ±3.0 Crosslinking cavity outlet 74±2 0.07±0.01 ±2.8

[0121] As shown in Table 5, for the gas film formed by the spiral airflow, the spiral airflow pitch is stable, the gas film thickness is 0.07-0.10 mm, and the temperature fluctuation range is no more than 3℃, which meets the uniformity requirements.

[0122] The base 111 is also provided with a second opening 115, which allows at least a portion of the protective gas to flow out.

[0123] The temperature range within the cross-linking chamber 210 is 230℃-250℃. Within this temperature range, the pipe material can undergo a cross-linking reaction, and the pipe material will also be heated. When the protective coating 123 is damaged, the temperature of the pipe material can be used to rupture the microcapsules and repair the protective coating.

[0124] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A support mechanism for a peroxide cross-linked polyethylene pipe system, characterized in that, include: Base; A support roller, rotatably connected to the base, has grooves on its surface for supporting the pipe. These grooves surround the roller surface, and the groove walls have multiple recessed holes arranged in an array. The diameter of each recessed hole is 0.1 mm, and the density N of the recessed holes is greater than or equal to 100 holes / cm². 2 The recessed hole is used to contact the protective gas and form a gas film on the groove wall; The groove wall is also provided with a protective coating, which includes polytetrafluoroethylene; The protective coating also includes microcapsules with a diameter ranging from 50 to 100 μm and a wall thickness of 1 to 5 μm, and the interior of the microcapsules is filled with siloxane.

2. The support mechanism of the peroxide cross-linked polyethylene pipe system according to claim 1, characterized in that: The capsule wall material of the microcapsule includes dicyclopentadiene.

3. The support mechanism of the peroxide cross-linked polyethylene pipe system according to claim 1, characterized in that: The base also includes a seat body and a hydraulic support device. The hydraulic support device is disposed on both sides of the seat body. The hydraulic support device is also provided with a connecting rod. The connecting rod is connected to both sides of the support roller, and the support roller is rotatably connected to the hydraulic support device through the connecting rod.

4. The support mechanism of the peroxide cross-linked polyethylene pipe system according to claim 3, characterized in that: The seat body has a receiving cavity with openings at the front and back, the support roller is disposed in the receiving cavity, and the connecting rod passes through the seat body.

5. The support mechanism of the peroxide cross-linked polyethylene pipe system according to claim 3, characterized in that, Also includes: A pressure sensor, which is disposed inside the support roller, is used to detect the pressure on the support roller; The controller is electrically connected to the pressure sensor and the hydraulic support device.

6. A system for manufacturing peroxide cross-linked polyethylene pipes, characterized in that, include: The support structure of the peroxide cross-linked polyethylene pipe system as described in any one of claims 1-5; A crosslinking furnace having a crosslinking chamber with openings at the front and back, wherein a support mechanism for the peroxide crosslinked polyethylene pipe system is disposed on at least one side of the crosslinking chamber.

7. The system for manufacturing peroxide cross-linked polyethylene pipes according to claim 6, characterized in that: The crosslinking furnace is provided with a first opening, which is used to introduce protective gas into the crosslinking chamber. The protective gas introduced through the first opening can form a spiral airflow on the pipe, and the spiral airflow forms a gas film on the groove wall.

8. The system for manufacturing peroxide cross-linked polyethylene pipe according to claim 6, characterized in that: The temperature range within the cross-linking chamber is 230℃-250℃.

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