Apparatus and Method for Preparing Gradient Multilayer Composite Corrugated Pipes

Abstract

This invention relates to an apparatus and method for preparing gradient multilayer composite corrugated pipes. The apparatus includes a lower end plate, a left mold, a right mold, a connecting pipe, a cooling device, and a raw material tank. The left and right molds form a cavity for forming the corrugated pipe. The raw material tank contains liquid composite material. The cooling device is installed on the outer surfaces of the left and right molds. The raw material tank is connected to the cavity via the connecting pipe, and a liquid pump is installed inside the cavity. The left and right molds are fixed to the lower end plate, which is connected to a motor that drives its rotation. When the lower end plate rotates, it drives the left and right molds to rotate, and the composite material is introduced into the cavity, completing the centrifugal forming process. This invention simplifies the corrugated pipe forming apparatus while improving the surface density of the product, enhancing the tensile and shear strength of the corrugated pipe, improving the forming accuracy of the corrugated pipe, and expanding the practical applications of the corrugated pipe, making it more suitable for high-requirement applications in aviation, aerospace, and other fields.

Description

Technical Field

[0001] This invention relates to the field of precision manufacturing of composite materials, and more specifically, to an apparatus and method for preparing gradient multilayer composite corrugated pipes. Background Technology

[0002] A bellows is a tubular elastic sensing element made of foldable corrugated sheets connected along the folding and stretching direction. It is manufactured from two types of materials: metal bellows and composite material bellows. Metal bellows serve functions such as protecting circuits from deformation, damping vibrations, and transporting fluids, and are widely used in aerospace, automotive, chemical, and instrumentation industries. Composite material bellows, due to their non-conductive properties, good compressive strength, corrosion and wear resistance, and excellent aging resistance, are often used in cable protection, conveying rocket propellants, mechanical equipment, automation control, automotive, and aerospace fields.

[0003] The traditional manufacturing method for composite corrugated pipes is extrusion molding, where molten raw material is extruded from a die and bonded to the die to form a profile with the same shape as the die. However, this traditional production method has the following disadvantages in actual production:

[0004] 1. Extruded products have poor surface density. Because the extrusion molding process involves squeezing the raw material through a die, it cannot guarantee excellent surface properties and may produce problems such as air bubbles, which seriously affect the quality of the product itself. This problem has a significant impact on the use of the product, especially when it is used in high-precision and high-requirement fields such as aerospace and automation control.

[0005] 2. Extrusion molding equipment is relatively complex. Extrusion molding equipment includes an extrusion unit and a die. The extrusion process requires corresponding mechanical mechanisms, making it quite complex. In actual production, the more complex the equipment, the greater the likelihood of malfunctions, which reduces production efficiency and impacts economic benefits.

[0006] 3. Adjusting the wall thickness of extruded products is quite difficult. The method for controlling wall thickness in extrusion molding is through the gaps created in the mold. Once the mold is determined, changing the wall thickness becomes very troublesome.

[0007] 4. Extruded products have lower precision. Because the pushing force of the extrusion device and the extrusion between the raw material and the die are not on the same horizontal plane during extrusion molding, the product will have lower precision during the molding process. This has a serious impact on industries with high precision requirements.

[0008] 5. Impurities in the raw materials of extruded products can affect product performance. During the extrusion molding process, the raw material is directly shaped through a mold after being extruded. However, after the raw material is heated and melted, impurities and other components such as water vapor may be mixed in, which will seriously affect the product's strength, rigidity, and other properties. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide an apparatus and method for preparing gradient multilayer composite corrugated pipes, which simplifies the corrugated pipe forming device, while improving the surface density of the product and enhancing the performance of the corrugated pipe.

[0010] The technical solution adopted by this invention to solve its technical problem is as follows: a gradient multilayer composite material corrugated pipe preparation device is constructed, including a lower end plate, a left mold, a right mold, a connecting pipe, a cooling device, and a raw material box. The left mold and the right mold form a cavity for forming the corrugated pipe. The raw material box contains liquid composite material. The cooling device is provided on the outer surface of the left mold and the right mold. The raw material box is connected to the cavity through the connecting pipe. A liquid pump is provided in the cavity. The left mold and the right mold are fixed on the lower end plate. The lower end plate is connected to a motor that drives its rotation. When the lower end plate rotates, it drives the left mold and the right mold to rotate. The composite material is introduced into the cavity to complete the centrifugal forming.

[0011] According to the above scheme, the left mold and the right mold are provided with straight wall area and curved surface area. The surface of the straight wall area and the curved surface area are treated differently by etching process, so that the arithmetic mean deviation Ra of the surface of the straight wall area and the curved surface area is proportional to the linear velocity, so as to ensure that the raw material liquid is uniformly attached to the mold when rotating, thereby realizing the uniform wall thickness distribution of composite material pipe.

[0012] The surface roughness formula obtained for the central angle of the curved surface is 0-90°:

[0013]

[0014] The surface roughness formula obtained from a central angle of 90-180° on a curved surface is as follows:

[0015]

[0016] Where r is the radius of the inner circle of the cavity, α is the central angle, and δ is the roughness coefficient.

[0017] According to the above scheme, the raw material box is equipped with a heating device for hot-melting composite materials.

[0018] According to the above scheme, a filter is provided on the connecting pipe.

[0019] According to the above scheme, the left mold and the right mold are fixed in the groove of the lower end plate, and the left mold and the right mold are connected by bolts.

[0020] This invention also provides a method for preparing a gradient multilayer composite corrugated pipe, utilizing the aforementioned gradient multilayer composite corrugated pipe preparation apparatus. The preparation method includes the following steps:

[0021] S1. The composite material raw material is heated in the raw material box to melt the composite material into a liquid;

[0022] S2. Transfer the raw materials into the mold cavity through the connecting pipe;

[0023] S3. The motor drives the lower end plate to rotate. Through centrifugal process, combined with the change in surface roughness of the cavity, the raw material is made to fit into the cavity, and the corrugated tube with irregular cross section is formed.

[0024] S4. After the irregular cross-section corrugated pipe in step S3 is formed, the cooling device is activated to lower the temperature and the composite material is cured.

[0025] S5. Grind the wall of the cured corrugated pipe and smooth the outer surface.

[0026] The apparatus and method for preparing gradient multilayer composite corrugated pipes according to the present invention have the following beneficial effects:

[0027] 1. This invention can filter out impurities present after the raw material is melted by using a filter on the connecting pipe, ensuring the purity of the raw material and preventing impurities from affecting the product performance during subsequent forming processes.

[0028] 2. The device of the present invention has a simple structure and a concise forming process, which avoids the high error rate of parts caused by complex devices. In actual production, the simplicity of the device can improve production efficiency and reduce problems caused by part failures.

[0029] 3. The products formed by the device of this invention have high surface density and precision. The main forming method used by this device is high-speed rotation. Through a centrifugal process, the raw material is brought into contact with the mold, and then solidified by a rapid cooling device. At high speeds of rotation, the raw material can be tightly bonded to the mold, ensuring production precision and surface density, reducing the generation of problems such as bubbles, and better meeting the high requirements of practical applications such as aerospace.

[0030] 4. The wall thickness of the product formed by the device of this invention can be easily adjusted. Traditional forming devices require changing the mold to alter the wall thickness of the corrugated pipe, which is cumbersome and inefficient. This device allows for control of the amount of raw material flowing into the mold by controlling the pump's on / off switch, thus changing the wall thickness. Furthermore, the mold surface can be treated with an etching process to ensure that the liquid raw material adheres evenly to the wall surface during rotation, guaranteeing uniform pipe wall thickness.

[0031] 5. The device of the present invention can be disassembled from the left mold and the right mold, assembled to the bottom, and formed into corrugated pipes of arbitrary length, which is convenient for application in many actual production scenarios.

[0032] 6. The device of the present invention can realize multi-layer corrugated pipes of different materials by changing the raw material box. Gradient materials can enhance the performance of corrugated pipes and expand the application range of corrugated pipes. Attached Figure Description

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0034] Figure 1 This is a schematic diagram of the structure of the gradient multilayer composite material corrugated pipe preparation device of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of a multi-layer composite corrugated pipe;

[0036] Figure 3 This is a flowchart of the method for preparing gradient multilayer composite corrugated pipes according to the present invention;

[0037] Figure 4 This is a fluid simulation diagram of the preparation process of the gradient multilayer composite corrugated pipe of the present invention;

[0038] Figure 5 These are schematic diagrams of the surface roughness in two embodiments. Detailed Implementation

[0039] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0040] like Figure 1 As shown, the gradient multilayer composite corrugated pipe manufacturing apparatus of the present invention includes a left mold 5, a right mold 4, a lower end plate 7, a cooling device 6, a connecting pipe 2, and a raw material tank 1. The upper surface of the lower end plate 7 has a groove, in which the left mold 5 and the right mold 4 are fixed. The raw material tank is connected to the mold via the connecting pipe 2. The cooling device 6 is located on the outer surface of the left mold 5 and the right mold 4. The left mold 5 and the right mold 4 form a molding cavity.

[0041] The raw material tank 1 can be heated at high temperatures to melt the composite material. A liquid pump inside the raw material tank 1 transports the melted liquid to the mold cavity through connecting pipe 2. A filter 3 is installed on connecting pipe 2 to filter water vapor and impurities, ensuring the purity of the raw material. The raw material tank 1 can be fitted with different materials to create multi-layer corrugated pipes made of various materials.

[0042] The left mold 5 and right mold 4 are made of 40Cr steel and require carbonitriding and surface hardening treatment. The bellows structure is as follows: Figure 2As shown, the left mold 5 and the right mold 4 are respectively set with straight wall area and curved surface area. According to the ratio of the outer diameter to the inner diameter of the pipe, the surfaces of the straight wall area and the curved surface area are treated differently by etching process, so that the arithmetic mean deviation Ra of the two surfaces is proportional to the linear velocity, ensuring that the raw material liquid can be evenly attached to the mold when rotating, thereby achieving uniform wall thickness of the pipe.

[0043] Based on this method, the surface roughness formula obtained for central angles of 0-90° is as follows:

[0044]

[0045] The surface roughness formula obtained from a central angle of 90-180° on a curved surface is as follows:

[0046]

[0047] Where r is the radius of the inner circle of the cavity, α is the central angle, and δ is the roughness coefficient.

[0048] Both the left mold 5 and the right mold 4 are fixed in the groove of the lower end plate 7 and connected by bolts. Both the left mold 5 and the right mold 4 can rotate with the lower end plate 7. The lower end plate 7 includes a turntable motor and a rotating shaft, which can rotate at high speed, simultaneously driving the left mold 5 and the right mold 4 to rotate, completing the centrifugal forming process. The groove of the lower end plate 7 can connect with the left mold 5 and the right mold 4 to form longer corrugated tubes, and the length of the corrugated tube can be controlled according to the actual use.

[0049] This device achieves gradient material forming of composite corrugated pipes by centrifugally rotating one or more raw materials to fully conform them to a mold. Furthermore, by controlling the surface roughness of the mold, it ensures uniform wall thickness in the corrugated pipe. This invention simplifies the corrugated pipe forming device while improving the surface density of the product, enhancing the tensile and shear strength of the corrugated pipe, increasing the forming accuracy, and expanding the practical applications of corrugated pipes, making them more suitable for demanding applications in aerospace and other fields.

[0050] like Figure 3 As shown, the present invention also provides a method for preparing a gradient multilayer composite corrugated pipe. Using the aforementioned gradient multilayer composite corrugated pipe preparation apparatus, the preparation method includes the following steps:

[0051] S1. The raw materials are heated in the raw material box by a heat source to melt the composite material into a liquid.

[0052] S2. Transfer the raw materials to the mold cavity through the connecting pipe.

[0053] S3. The lower end plate motor drives the shaft to rotate at high speed. Through centrifugal processing, the raw material is bonded to the mold to form a corrugated pipe with an irregular cross-section. The simulation results of the corrugated pipe fluid domain are as follows: Figure 4As shown.

[0054] S4. When the forming step is completed, the cooling device is activated to lower the temperature, and the composite material is cured to complete the forming.

[0055] S5. Grind the wall of the formed corrugated pipe and smooth the outer surface.

[0056] Example 1:

[0057] Forming of 1.8mm thick composite material corrugated pipe:

[0058] High-density polyethylene (HDPE) is selected as the material. After hot-melting, it is fed into the raw material tank and thoroughly stirred. Following thorough stirring, an 80LG50-20x2 liquid pump is used to pump the raw material into the mold cavity through a connecting pipe. The material passes through a filter along the way; a degassing filter is selected to degas and filter solid impurities from the liquid, removing impurities from the liquid polyethylene.

[0059] The left and right molds are made of 40Cr steel, undergoing carbonitriding and surface hardening. The large diameter of the mold cavity is 200mm, and the small diameter is 180mm, with a large diameter to small diameter ratio of 10 / 9. The left and right molds are then etched to achieve a Ra coefficient of 10 / 9 for both the straight-walled and curved-surface areas, with a minimum Ra value of 0.2 for the curved-surface areas and a roughness coefficient of 0.02. Figure 5 As shown, the surface roughness can be finely adjusted according to the process during actual production.

[0060] Both the left and right molds are fixed in the grooves of the lower end plate and are connected by bolts. Both the left and right molds can rotate with the lower end plate.

[0061] The mold is connected to the lower base plate via six M6 bolts. The lower base plate houses an ACM13030M2E-51-B six-pole motor with a rotation speed of 1000 rpm. When material is injected into the cavity, the motor starts, driving the mold to rotate at high speed via a shaft. This high-speed rotation lasts for 25 minutes, controlling the corrugated pipe wall thickness at 1.8 mm. After 20 minutes, the cooling system is activated. Cooling then continues while the high-speed rotation continues. Rotation stops after 25 minutes, completing the molding process. The mold is then removed, yielding a composite material corrugated pipe with an irregular cross-section.

[0062] Example 2:

[0063] 3mm wall thickness composite material corrugated pipe forming:

[0064] High-density polyethylene (HDPE) is selected as the material. After hot-melting, it is fed into a raw material tank and thoroughly stirred. Following thorough stirring, a 65DL32-15x4 liquid pump is used to pump the raw material into the mold cavity through a connecting pipe. The material passes through a filter along the way; a degassing filter is selected to degas and filter solid impurities from the liquid, removing impurities from the liquid polyethylene.

[0065] The left and right molds are made of 40Cr steel, undergoing carbonitriding and surface hardening. The large diameter of the mold cavity is 500mm, and the small diameter is 460mm, with a large diameter to small diameter ratio of 25 / 23. The left and right molds are then processed using etching, with a minimum Ra value of 0.4 and a roughness coefficient of 0.018 for the curved surface area. The surface roughness of the mold is adjusted according to the curve shown in the figure below. Figure 5 As shown, the surface roughness can be finely adjusted according to the process during actual production.

[0066] Both the left and right molds are fixed in the grooves of the lower end plate and are connected by bolts. Both the left and right molds can rotate with the lower end plate.

[0067] The mold is connected to the lower base plate via six M6 bolts. The lower base plate houses a Y315M-4 four-pole motor with a rotation speed of 1500 r / min. When material is injected into the cavity, the motor starts, driving the mold to rotate at high speed via a shaft. This high-speed rotation lasts for 70 minutes, with the corrugated pipe wall thickness controlled at 3 mm. After 59 minutes, the cooling system is activated. Cooling then continues while the high-speed rotation continues. Rotation stops after 70 minutes, completing the molding process. The mold is then removed, yielding a composite material corrugated pipe with an irregular cross-section.

[0068] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A device for preparing gradient multilayer composite corrugated pipes, characterized in that, The device includes a lower end plate, a left mold, a right mold, a connecting pipe, a cooling device, and a raw material box. The left and right molds form a cavity for forming a corrugated pipe. The raw material box contains liquid composite material. The cooling device is installed on the outer surface of the left and right molds. The raw material box is connected to the cavity through the connecting pipe. A liquid pump is installed in the cavity. The left and right molds are fixed on the lower end plate. The lower end plate is connected to a motor that drives its rotation. When the lower end plate rotates, it drives the left and right molds to rotate. The composite material is introduced into the cavity to complete the centrifugal forming. The left and right molds are provided with straight wall areas and curved surface areas. The surfaces of the straight wall areas and curved surface areas are treated differently by etching process, so that the arithmetic mean deviation Ra of the surface of the straight wall areas and curved surface areas is proportional to the linear velocity, ensuring that the raw material liquid is uniformly attached to the mold when rotating, thereby achieving uniform wall thickness distribution of composite material pipes. The surface roughness formula obtained for the central angle of the curved surface is 0-90°: The surface roughness formula obtained from a central angle of 90-180° on a curved surface is as follows: Where r is the radius of the inner circle of the cavity. For the central angle, This is the roughness coefficient.

2. The apparatus for preparing gradient multilayer composite corrugated pipes according to claim 1, characterized in that, The raw material box is equipped with a heating device for hot-melting composite materials.

3. The apparatus for preparing gradient multilayer composite corrugated pipes according to claim 1, characterized in that, The connecting pipe is equipped with a filter.

4. The apparatus for preparing gradient multilayer composite corrugated pipes according to claim 1, characterized in that, The left and right molds are fixed in the grooves of the lower end plate and are connected by bolts.

5. A method for preparing a gradient multilayer composite corrugated pipe, characterized in that, The fabrication method using the gradient multilayer composite corrugated pipe fabrication apparatus of claim 1 includes the following steps: S1. The composite material raw material is heated in the raw material box to melt the composite material into a liquid; S2. Transfer the raw materials into the mold cavity through the connecting pipe; S3. The motor drives the lower end plate to rotate. Through centrifugal process, combined with the change in surface roughness of the cavity, the raw material is made to fit into the cavity, and the corrugated tube with irregular cross section is formed. S4. After the irregular cross-section corrugated pipe in step S3 is formed, the cooling device is activated to lower the temperature and the composite material is cured. S5. Grind the wall of the cured corrugated pipe and smooth the outer surface.

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