A production equipment for composite pipes

Abstract

The present invention provides a production device for composite pipes, belonging to the field of composite pipe technology. It solves the problems of low dimensional accuracy and uneven wall thickness in the process of producing composite pipes in the prior art. The production device for composite pipes includes a forming mold, a vacuum sizing box and an air plug. The forming mold includes an outer mold sleeve and a core mold arranged in the outer mold sleeve. A forming cavity is formed between the core mold and the outer mold sleeve. The pipe inlet of the vacuum sizing box is directly opposite to the discharge port of the outer mold sleeve. The air plug is connected to the core mold by a pull rope and can be moved into the vacuum sizing box. A flexible sealing sheet is provided on the air plug. The edge of the sealing sheet is circular and the diameter is larger than the outer diameter of the core mold. An air inlet passage is provided in the core mold, and the air outlet of the air inlet passage is located on the end face of the core mold near one end of the vacuum sizing box. The present invention can ensure that the composite pipe has high dimensional accuracy, good wall thickness uniformity and low stress.

Description

Technical Field

[0001] The invention belongs to the technical field of composite pipes and relates to production equipment for composite pipes. Background Art

[0002] With the continuous expansion of cities and the continued exploitation of oil and natural gas, the demand for transportation pipelines is increasing. Traditional steel pipelines, with their poor corrosion resistance and difficulty in handling, are no longer suitable for current needs. Fiber-reinforced composite pipes are widely used due to their low density, high strength, and excellent mechanical properties, including good processability, chemical stability, and heat resistance.

[0003] Existing fiber-reinforced composite pipes usually consist of three layers from the inside out: an inner layer, a reinforcement layer, and an outer layer. In terms of manufacturing principle, the pipe blank is first extruded through an extruder, and then the reinforcing fibers are wound around the surface of the pipe blank through a winding machine and bonded with an adhesive to form a reinforced fiber composite pipe.

[0004] For example, a patent document discloses a fiber mesh tape wrapped reinforced composite pipe and its preparation process and equipment (application number: CN201210502640.3). This equipment first extrudes the resin raw material through a core pipe extruder and a core pipe extrusion die, and then sizing it in a pre-vacuum spray sizing box to produce a core pipe. Under the traction of the pre-traction machine, the core pipe is successively wrapped and reinforced by a first winding machine and a second winding machine. The core pipe then passes through a post-heating box, a post-coating extruder, and a post-coating die. The coating die extrude and coat the outer layer of the pipe on the outer surface of the wrapped pipe, and finally sizing it in a post-vacuum spray sizing box to form the pipe product. This device has the following shortcomings: First, the device extrudes a core tube before wrapping a reinforcement layer on the core tube surface. Due to the very thin thickness of the reinforcing fiber, the bonding layer formed by the fiber wrapping on the core tube surface is very small. At the same time, the sequential winding of the fiber layers often results in limited bonding strength in the contact area between the fibers, resulting in weak interlayer bonding and limited effect on improving the quality of the composite pipe, especially its strength. In addition, when sizing the composite pipe, the device relies on the negative pressure generated by the vacuum sizing box to expand and deform the pipe, so that it adheres closely to the inner wall of the sizing sleeve to achieve sizing. This method can meet the sizing accuracy requirements for some thin pipes or pipes with lower strength requirements. However, when sizing thicker pipes wrapped with reinforcing material, this method is prone to insufficient fit between the pipe and the sizing sleeve, resulting in a series of problems such as low dimensional accuracy and low wall thickness uniformity. Summary of the Invention

[0005] The purpose of the present invention is to address the above-mentioned problems in the existing technology and propose a production equipment for composite pipes. The technical problem solved by the present invention is: how to make the manufactured composite pipes have high dimensional accuracy and good wall thickness uniformity.

[0006] The objectives of the present invention can be achieved through the following technical solutions: a production equipment for composite pipes, comprising a forming mold and a vacuum sizing box, the forming mold comprising an outer mold sleeve and a core mold arranged in the outer mold sleeve, a forming cavity is formed between the core mold and the outer mold sleeve, the pipe inlet of the vacuum sizing box is directly opposite to the discharge port of the outer mold sleeve, and is characterized in that the production equipment also includes an air plug, which is connected to the core mold by a pull rope and can be moved into the vacuum sizing box, and a flexible sealing sheet is provided on the air plug, the edge of the sealing sheet is circular and the diameter is larger than the outer diameter of the core mold, an air inlet passage is provided in the core mold and the air outlet of the air inlet passage is located on the end face of the core mold close to one end of the vacuum sizing box.

[0007] During production, the composite pipe is pulled from the forming cavity of the mold by a traction machine and then enters the vacuum sizing chamber through the pipe inlet. The air plug remains inside the composite pipe. The composite pipe is pulled out of the mold along the outer wall of the core mold, and the inner diameter of the composite pipe is consistent with the outer wall of the core mold. The air plug is equipped with a flexible sealing sheet. The diameter of the sealing sheet is larger than the outer diameter of the core mold and, therefore, the inner diameter of the composite pipe. This allows the sealing sheet to deform when it contacts the inner wall of the composite pipe, thereby sealing the inner hole of the composite pipe.

[0008] Since the air outlet of the air inlet passage is located on the end face of the core mold close to the vacuum sizing box, the gas discharged from the air outlet will enter the interior of the composite pipe, thereby forming an internal squeeze on the inner cavity of the composite pipe. At the same time, the pull rope of the air plug will straighten, allowing the air plug to enter the vacuum sizing box. In this way, the composite pipe is subjected to both the external suction force of the negative pressure in the vacuum sizing box and the internal squeeze of the high-pressure gas inside the composite pipe, so that the composite pipe can fit well on the sizing sleeve of the vacuum sizing box, ensuring that the composite pipe has high dimensional accuracy, good wall thickness uniformity and low stress.

[0009] In addition, the air plug is connected to the core mold by a pull rope. Therefore, during the startup of the equipment, the air plug can be first removed from the vacuum sizing box, thereby ensuring that the reinforcing fiber can pass through the vacuum sizing box and be connected to the traction machine, and the reinforcing fiber is compounded at the forming mold to form a composite pipe. In this way, the reinforcing fiber is pulled and moved by the traction machine, so that the finished pipe can be continuously pulled forward; more importantly, since the air plug enters the vacuum sizing box when the pull rope is extended, the air plug can enter a deeper position in the vacuum sizing box, and the air plug is far away from the forming mold, which can increase the pressure holding length of the composite pipe, greatly strengthening the internal gas extrusion effect on the composite pipe, and making the composite pipe fit well on the sizing sleeve of the vacuum sizing box, so that the dimensional accuracy of the composite pipe is high.

[0010] In the above-mentioned composite pipe production equipment, the end of the core mold close to the vacuum sizing box is the rear end of the core mold, and the air inlet passage includes a ventilation groove provided on the rear end surface of the core mold and an air storage cavity located inside the core mold and connected to the ventilation groove. The air plug can be embedded in the ventilation groove and seal the ventilation groove. Before the equipment is turned on, the air plug can be placed in the ventilation groove and positioned by the ventilation groove. During the normal production process of the equipment, as the composite pipe is continuously pulled out of the molding cavity by the traction machine, the gas in the ventilation groove has the effect of pushing the air plug outward, so that the air plug can automatically move out of the ventilation groove and straighten the pull rope. The position of the air plug is pre-positioned by the ventilation groove, so that the air plug will not tilt in the composite pipe, ensuring the sealing effect of the air plug and preventing the sizing effect from being affected by the tilt of the air plug.

[0011] In the aforementioned composite pipe production equipment, the gas plug includes a connecting shaft on which two aforementioned sealing plates are spaced apart along its length. Both sealing plates are annular and have equal outer diameters. These two sealing plates form a double seal, enhancing the gas plug's sealing effectiveness. Furthermore, both sealing plates contact the inner wall of the composite pipe, ensuring excellent stability and preventing tilting. The sealing plates maintain high concentricity with the composite pipe, allowing the gas plug to effectively support the inner wall of the composite pipe, thereby ensuring high dimensional accuracy and uniform wall thickness of the composite pipe.

[0012] In the above-mentioned production equipment of the composite pipe, the ventilation groove is in the shape of a circular hole and is arranged coaxially with the core mold. One of the two sealing plates is located in the middle of the connecting shaft and is clamped by two small clips, and the other sealing plate is located at one end of the connecting shaft. The other end of the connecting shaft is connected to the pull rope. The sealing plate located at one end of the connecting shaft is clamped by a small clip and a large clip and the large clip is located on the side of the sealing plate facing away from the other sealing plate. The outer diameter of the large clip is equal to or approximately equal to the diameter of the ventilation groove, and the outer diameter of each small clip is smaller than the diameter of the ventilation groove.

[0013] The arrangement of the small and large clips ensures that the sealing piece can be clamped and stably installed on the connecting shaft. After the gas enters the composite pipe, it will first be blocked by the sealing piece in the middle of the connecting shaft. At this time, even if some gas passes through the gap between the sealing piece and the inner wall of the composite pipe, the sealing piece at one end of the connecting shaft can provide a second blockage. Moreover, due to the large size of the large clip, the amount of deformation of the sealing piece is limited, so the sealing ring has a stronger sealing ability, thereby improving the internal squeezing effect of the composite pipe by the gas, and then making the composite pipe fit well on the sizing sleeve of the vacuum sizing box, ensuring the high dimensional accuracy and good wall thickness uniformity of the composite pipe.

[0014] In the composite pipe production equipment described above, the draw rope is a steel wire rope. A first tether hole is defined at the other end of the connecting shaft. A connecting plate is fixedly attached to the inner wall of the air storage chamber, and a second tether hole is defined in the connecting plate. The ends of the draw rope are connected to the first and second tether holes, respectively. Steel wire ropes are low-cost and high-strength. By connecting the ends of the draw rope to the first and second tether holes, respectively, the draw rope connection is more convenient.

[0015] In the above-mentioned composite pipe production equipment, the production equipment also includes an outer tube, one end of which extends into the outer mold sleeve, and an annular cavity facing the molding cavity is formed between the outer peripheral wall of the outer tube and the inner peripheral wall of the outer mold sleeve. An air inlet pipe connected to the air storage cavity is also provided in the outer tube.

[0016] The forming cavity within the mold is designed to allow the molten material to flow through, forming a tube with the desired cross-sectional shape. This production equipment incorporates an outer tube. During manufacturing, a continuous stream of reinforcing fibers is wound around the outer wall of the outer tube using an existing fiber winding device, such as a bobbin winder. Since an annular cavity, directly facing the forming cavity, is formed between the outer tube and the outer mold sleeve, the reinforcing fibers, driven by a traction machine, continuously pass through the forming cavity, intersecting and compounding with the molten material within it. Ultimately, a fiber-reinforced composite tube emerges from the mold.

[0017] Obviously, the production principle of the present invention is completely different from that of the existing equipment. The present invention does not first extrude the tube blank through an extruder and then use a winding machine to wrap the reinforcing fibers on the surface of the tube blank. Instead, the molten material and continuous reinforcing fibers are formed into a composite pipe in one step in the molding mold. In this way, the molten material can be compatible and infiltrated with the reinforcing fibers in the molding mold, so the bonding effect is better and the strength is higher. There is no problem of weak interlayer bonding causing the pipe strength to weaken in the composite pipe produced by the existing equipment.

[0018] Because the composite pipe is formed using the aforementioned one-step process, when it enters the vacuum sizing chamber for sizing, the reinforced fiber layer within the composite pipe requires a greater deformation force than pure PE or PVC pipe. The present invention's internal extrusion combined with external vacuum sizing structure, combined with a long-term pressure-maintaining process within the composite pipe, meets this deformation force requirement. This one-step composite pipe exhibits not only high strength, but also high dimensional accuracy and uniform wall thickness.

[0019] In the above-mentioned composite pipe production equipment, an inner tube for supplying molten material into the molding cavity is passed through the outer tube. A heat conductor in a straight cylindrical shape and sleeved on the outer peripheral wall of the inner tube is also provided in the outer tube. A heating element is provided on the heat conductor. A plurality of slots extending along the length direction are provided on the outer peripheral wall of the heat conductor. The plurality of slots are arranged in sequence along the circumference of the heat conductor. A temperature regulating component made of a heat-conducting material is detachably inserted in the slot, and the temperature regulating component is in contact with the outer peripheral wall of the outer tube.

[0020] When in use, according to the required heating temperature of the outer tube, the heat conduction area between the heat conductor and the outer tube can be adjusted by increasing or decreasing the number of temperature regulating members in the slots on the heat conductor. When the number of temperature regulating members in the slots is increased, the heat conduction area between the heat conductor and the outer tube becomes larger, so that the heating element on the heat conductor can transfer more heat to the outer tube through the heat conductor in the same period of time, and the heating temperature of the outer tube becomes higher. Conversely, when the number of temperature regulating members in the slots is reduced, the heat conduction area between the heat conductor and the outer tube becomes smaller, so that the heating element on the heat conductor can transfer less heat to the outer tube through the heat conductor in the same period of time, and the heating temperature of the outer tube becomes lower. At the same time, Whether the number of temperature regulating parts in the several slots of the pipe increases or decreases, the heat conduction area between the heat conductor and the inner pipe remains unchanged, so that the heat conducted to the inner pipe and the outer pipe by the heating element through the same heat conductor can be different, thereby realizing differentiated heat transmission of the heating structure of the fiber composite pipe forming equipment, that is, the temperature of the inner pipe can be maintained at 180-250 degrees, and the temperature of the outer pipe can be maintained at 120-180 degrees, so as to heat the reinforcing fiber wrapped on the surface of the outer pipe, and at the same time keep the thermoplastic plastic in the inner pipe in a fluid state, thereby improving the bonding quality of the reinforcing fiber and the PE melt, thereby improving the molding quality of the fiber composite pipe molding equipment and the strength of the composite pipe.

[0021] In the aforementioned composite pipe production equipment, the slot has an arcuate cross-section, the thermostat is a straight strip with an arcuate surface that mates with the inner circumferential wall of the outer tube, and at least one end of the slot penetrates the end face of the heat conductor. The slot's arcuate cross-section minimizes the area of ​​the heat conductor near the inner tube that is removed due to the slot, thereby meeting and maintaining the required higher temperature of the inner tube. At least one end of the slot penetrates the heat conductor to form an opening for inserting the thermostat, facilitating its installation and removal.

[0022] In the aforementioned composite pipe production equipment, the heat conductor has a central hole through which the inner tube passes and abuts against the outer circumferential wall of the inner tube. The heating elements comprise a plurality of heating tubes arranged along the length of the heat conductor, and the heating tubes are evenly spaced along the circumference of the heat conductor. This structure allows heat from the heating elements to be more evenly transferred to the inner and outer circumferential walls of the heat conductor, thereby achieving more uniform heat distribution across the surfaces of the inner and outer tubes, thereby improving the molding quality of the fiber composite pipe molding equipment.

[0023] The composite pipe production equipment described above also includes an extruder, a support frame, and a winding machine. These are arranged in a straight line, one after the other, along with a forming die and a vacuum sizing chamber. The outer pipe passes through the winding machine and is connected to the support frame. One end of the inner pipe is connected to the extruder. The molten PE material extruded by the extruder is transported through the inner pipe to the forming die for composite bonding with the reinforcing fiber.

[0024] Compared with the existing technology, the production equipment of the composite pipe has the following advantages:

[0025] 1. The production principle of the present invention is completely different from that of existing equipment. In the present invention, instead of first extruding a tube blank through an extruder and then winding the reinforcing fibers onto the surface of the tube blank through a winding machine, the molten material and continuous reinforcing fibers are formed into a composite pipe in a single step within a forming mold. In this way, the molten material can be compatible and infiltrated with the reinforcing fibers within the forming mold, resulting in a better bonding effect and higher strength. The problem of weak interlayer bonding causing weakened pipe strength, which exists in composite pipes produced by existing equipment, does not exist.

[0026] 2. In the present invention, the gas discharged from the gas outlet will enter the interior of the composite pipe, thereby forming an internal squeeze on the inner cavity of the composite pipe. At the same time, the pull rope of the gas plug will straighten, allowing the gas plug to enter the vacuum sizing box. In this way, the composite pipe is subjected to both the external suction force of the negative pressure in the vacuum sizing box and the internal squeezing effect of the high-pressure gas inside the composite pipe, so that the composite pipe can fit well on the sizing sleeve of the vacuum sizing box, ensuring that the composite pipe has high dimensional accuracy, good wall thickness uniformity, and low stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of this production equipment.

[0028] Figure 2 It is a partial cross-sectional view of this production equipment.

[0029] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0030] Figure 4 This is a cross-sectional view of the forming mold part of this production equipment.

[0031] Figure 5 yes Figure 4 Enlarged view of point B in the middle.

[0032] Figure 6 This is a cross-sectional view of the forming die and outer tube in this production equipment.

[0033] Figure 7 It is a structural diagram of the air plug in this production equipment.

[0034] Figure 8 It is a schematic cross-sectional view of the outer tube portion in the second embodiment.

[0035] Figure 9 It is a schematic end view of the heat conductor, heating element and temperature regulating component in the second embodiment.

[0036] In the figure, 1. vacuum sizing box; 1a. pipeline inlet; 1b. sizing sleeve; 2. forming mold; 21. outer mold sleeve; 211. discharge port; 22. core mold; 23. forming cavity; 3. air plug; 31. sealing plate; 32. connecting shaft; 33. small clip; 34. large clip; 35. tether hole 1; 4. pull rope; 5. air inlet passage; 51. air outlet; 52. ventilation groove; 53. air storage cavity; 6. connecting plate; 61. tether hole 2; 7. outer tube; 8. annular cavity; 9. air inlet pipe; 10. inner tube; 11. heat conductor; 111. slot; 112. center hole; 12. heating element; 13. temperature regulating component; 14. extruder; 15. support frame; 16. winding machine; 17. traction machine; 18. composite pipe. DETAILED DESCRIPTION

[0037] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0038] Example 1

[0039] like Figure 1 As shown, the production equipment of the composite pipe includes an extruder 14, a support frame 15, a winding machine 16, a forming mold 2, a vacuum sizing box 1 and a traction machine 17 arranged in sequence along a straight line.

[0040] like Figure 2 and Figure 3As shown, the production equipment also includes an outer tube 7 and an air plug 3. The forming mold 2 includes an outer mold sleeve 21 and a core mold 22 disposed within the outer mold sleeve 21. A forming cavity 23 is formed between the core mold 22 and the outer mold sleeve 21. The pipe inlet 1a of the vacuum calibrating box 1 is directly opposite the discharge port 211 of the outer mold sleeve 21. The air plug 3 is connected to the core mold 22 via a pull rope 4 and can be moved into the vacuum calibrating box 1. The air plug 3 is provided with a flexible sealing sheet 31. The edge of the sealing sheet 31 is circular and its diameter is larger than the outer diameter of the core mold 22. The core mold 22 has an air inlet passage 5, and the air outlet 51 of the air inlet passage 5 is located on the end surface of the core mold 22 near the vacuum calibrating box 1.

[0041] Combine Figures 4 to 6 As shown, an inner tube 10 is inserted into the outer tube 7 for supplying molten material into the molding cavity 23. One end of the inner tube 10 is connected to the extruder 14, and the other end extends into the molding die 2. One end of the outer tube 7 extends from the feed port of the outer mold sleeve 21 into the outer mold sleeve 21. An annular cavity 8 is formed between the outer circumferential wall of the outer tube 7 and the inner circumferential wall of the outer mold sleeve 21, facing the molding cavity 23. The other end of the outer tube 7 passes through the winding machine 16 and is connected to the support frame 15. The outer tube 7 is also provided with an air inlet pipe 9 connected to the air storage chamber 53. The molding cavity 23 in the molding die 2 is used to allow the molten material to flow through, so that a pipe with a desired cross-sectional shape is formed in the molding cavity 23. This production equipment is provided with an outer tube 7. During manufacturing, a continuous stream of reinforcing fibers is wound around the outer circumferential wall of the outer tube 7 using an existing fiber winding device, such as a winding machine 16. Since an annular cavity 8 is formed between the outer tube 7 and the outer mold sleeve 21, directly opposite the molding cavity 23, the reinforcing fibers continuously pass through the molding cavity 23 under the action of the traction machine 17, intersecting and compounding with the molten material within the molding cavity 23, ultimately forming a fiber-reinforced composite tube that extends from the molding die 2. Gas discharged from the gas outlet 51 enters the interior of the composite tube 18, thereby exerting internal pressure on the inner cavity of the composite tube 18. Simultaneously, the pull cord 4 of the gas plug 3 straightens, allowing the gas plug 3 to enter the vacuum sizing chamber 1. In this way, the composite tube is subjected to both the external suction force of the negative pressure within the vacuum sizing chamber 1 and the internal pressure of the high-pressure gas within the composite tube 18. This allows the composite tube 18 to fit snugly against the sizing sleeve 1b of the vacuum sizing chamber 1, ensuring high dimensional accuracy, uniform wall thickness, and low stress on the composite tube 18.

[0042] During the equipment manufacturing process, Figure 2 As shown, the vacuum calibrating box 1 and the forming mold 2 are close together. The vacuum calibrating box 1 can be moved. When the air plug 3 needs to be placed, the vacuum calibrating box 1 can be moved in the direction away from the forming mold 2 so that there is a gap between the vacuum calibrating box 1 and the forming mold 2 for the air plug 3 to be installed.

[0043] Further, such as Figure 2 、 Figure 4 and Figure 5 As shown, the end of the core mold 22 closest to the vacuum calibrating box 1 is the rear end of the core mold 22. The air inlet passage 5 includes a vent groove 52 provided on the rear end surface of the core mold 22 and an air storage chamber 53 located inside the core mold 22 and connected to the vent groove 52. The air plug 3 can be inserted into the vent groove 52 to seal the vent groove 52. Before the equipment is turned on, the air plug 3 can be placed in the vent groove 52 and positioned by the vent groove 52.

[0044] like Figure 5 and Figure 7 As shown, the air plug 3 includes a connecting shaft 32, on which two sealing sheets 31 are spaced apart along its length. Both sealing sheets 31 are annular and have equal outer diameters. The vent groove 52 is circular and coaxial with the core mold 22. One of the two sealing sheets 31 is located in the middle of the connecting shaft 32 and is clamped by two small clips 33. The other sealing sheet 31 is located at one end of the connecting shaft 32. The other end of the connecting shaft 32 is connected to the pull rope 4. The sealing sheet 31 at one end of the connecting shaft 32 is clamped by a small clip 33 and a large clip 34. The large clip 34 is located on the side of the sealing sheet 31 facing away from the other sealing sheet 31. The outer diameter of the large clip 34 is equal to or approximately equal to the diameter of the vent groove 52. The outer diameter of each small clip 33 is smaller than the diameter of the vent groove 52. The pull rope 4 is a steel wire rope, and a tether hole 35 is provided at the other end of the connecting shaft 32. A connecting piece 6 is fixedly connected to the inner wall of the air storage chamber 53, and a tether hole 2 61 is provided on the connecting piece 6. The two ends of the pull rope 4 are respectively connected to the tether hole 35 and the tether hole 35.

[0045] Example 2

[0046] As a further optimization of the first embodiment, Figure 8 and Figure 9As shown, the outer tube 7 is further provided with a straight cylindrical heat conductor 11 that is sleeved on the outer circumferential wall of the inner tube 10. A heating element 12 is mounted on the heat conductor 11. The outer circumferential wall of the heat conductor 11 is provided with a plurality of slots 111 extending along its length. These slots 111 are arranged sequentially along the circumference of the heat conductor 11. A thermostat 13 made of a heat-conducting material is removably inserted into each slot 111 and contacts the outer circumferential wall of the outer tube 7. The slots 111 have an arc-shaped cross-section, and the thermostat 13 is a straight bar with an arc-shaped surface that mates with the inner circumferential wall of the outer tube 7. At least one end of the slot 111 passes through the end face of the heat conductor 11. The heat conductor 11 has a central hole 112 for the inner tube 10 to pass through and abuts against the outer peripheral wall of the inner tube 10. The heating elements 12 are a plurality of heating tubes arranged along the length direction of the heat conductor 11. The plurality of heating tubes are evenly arranged along the circumference of the heat conductor 11.

[0047] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

[0048] Although this article frequently uses terms such as 1. vacuum sizing box; 1a. pipe inlet; 1b. sizing sleeve; 2. molding die; 21. outer mold sleeve; 211. discharge port; 22. core mold; 23. molding cavity; 3. air plug; 31. sealing plate; 32. connecting shaft; 33. small clip; 34. large clip; 35. tether hole one; 4. pull rope; 5. air inlet passage; 51. air outlet; 52. ventilation groove; 53. air storage cavity; 6. connecting plate; 61. tether hole two; 7. outer tube; 8. annular cavity; 9. air inlet pipe; 10. inner tube; 11. heat conductor; 111. slot; 112. center hole; 12. heating element; 13. temperature control component; 14. extruder; 15. support frame; 16. winding machine; 17. traction machine; 18. composite pipe, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; any additional limitation construed in them would be contrary to the spirit of the present invention.

Claims

1. A production device for a composite pipe, comprising a vacuum sizing box (1) and a forming mold (2), wherein the forming mold (2) comprises an outer mold sleeve (21) and a core mold (22) arranged in the outer mold sleeve (21), a forming cavity (23) is formed between the core mold (22) and the outer mold sleeve (21), and a pipe inlet (1a) of the vacuum sizing box (1) is directly opposite to a discharge port (211) of the outer mold sleeve (21), characterized in that: The production equipment also includes an air plug (3), which is connected to the core mold (22) through a pull rope (4) and can be moved into the vacuum sizing box (1). The air plug (3) is provided with a flexible sealing sheet (31), the edge of the sealing sheet (31) is circular and the diameter is larger than the outer diameter of the core mold (22), the core mold (22) has an air inlet passage (5), and the air outlet (51) of the air inlet passage (5) is located near the core mold (22). On the end surface of one end of the empty sizing box (1), the end of the core mold (22) close to the vacuum sizing box (1) is the rear end of the core mold (22), the air inlet passage (5) includes a vent groove (52) provided on the rear end surface of the core mold (22) and an air storage cavity (53) located inside the core mold (22) and communicating with the vent groove (52), the air plug (3) can be embedded in the vent groove (52) and seal the vent groove (52), and the air plug (3) includes a connecting shaft ( 32), the connecting shaft (32) is provided with two sealing sheets (31) spaced apart along its length direction, the two sealing sheets (31) are both annular and have equal outer diameters, the vent groove (52) is in the shape of a circular hole and is coaxially arranged with the core mold (22), one of the two sealing sheets (31) is located in the middle of the connecting shaft (32) and is clamped by two small clamps (33), and the other sealing sheet (31) is located at the middle of the connecting shaft (32) One end of the connecting shaft (32) is connected to the drawstring (4), and the other end of the connecting shaft (32) is connected to the drawstring (4). The sealing sheet (31) at one end of the connecting shaft (32) is clamped by a small clamp (33) and a large clamp (34), and the large clamp (34) is located on the side of the sealing sheet (31) facing away from the other sealing sheet (31). The outer diameter of the large clamp (34) is equal to or approximately equal to the diameter of the ventilation groove (52), and the outer diameter of each small clamp (33) is smaller than the diameter of the ventilation groove (52).

2. The production equipment of the composite pipe according to claim 1, characterized in that: The pull rope (4) is a steel wire rope, and a tether hole (35) is provided at the other end of the connecting shaft (32). A connecting piece (6) is fixedly connected to the inner wall of the air storage chamber (53), and a tether hole (61) is provided on the connecting piece (6). The two ends of the pull rope (4) are respectively connected to the tether hole (35) and the tether hole (35).

3. The production equipment of the composite pipe according to claim 1 or 2, characterized in that: The production equipment further comprises an outer tube (7), one end of which extends into the outer mold sleeve (21), and an annular cavity (8) which is directly opposite to the molding cavity (23) is formed between the outer peripheral wall of the outer tube (7) and the inner peripheral wall of the outer mold sleeve (21), and an air inlet pipe (9) which is connected to the air storage cavity (53) is also provided in the outer tube (7).

4. The production equipment of the composite pipe according to claim 3, characterized in that: An inner tube (10) for supplying molten material into the molding cavity (23) is provided in the outer tube (7). A heat conductor (11) in a straight cylindrical shape and sleeved on the outer peripheral wall of the inner tube (10) is also provided in the outer tube (7). A heating element (12) is provided on the heat conductor (11). A plurality of slots (111) extending along the length direction of the heat conductor (11) are provided on the outer peripheral wall. The plurality of slots (111) are arranged in sequence along the circumference of the heat conductor (11). A temperature regulating member (13) made of a heat-conducting material is detachably inserted in the slot (111). The temperature regulating member (13) is in contact with the outer peripheral wall of the outer tube (7).

5. The production equipment of the composite pipe according to claim 4, characterized in that: The cross section of the slot (111) is arc-shaped, the temperature regulating element (13) is straight and has an arc surface that fits the inner circumferential wall of the outer tube (7), and at least one end of the slot (111) passes through the end surface of the heat conductor (11).

6. The production equipment of the composite pipe according to claim 5, characterized in that: The heat conductor (11) has a central hole (112) for the inner tube (10) to pass through and abutting against the outer peripheral wall of the inner tube (10); the heating element (12) is a plurality of heating tubes arranged along the length direction of the heat conductor (11); and the plurality of heating tubes are evenly arranged along the circumference of the heat conductor (11).

7. The production equipment of the composite pipe according to claim 4, characterized in that: The production equipment further comprises an extruder (14), a support frame (15), and a winding machine (16); the extruder (14), the support frame (15), the winding machine (16), the forming die (2), and the vacuum sizing box (1) are arranged in sequence along a straight line; the outer tube (7) passes through the winding machine (16) and is connected to the support frame (15); and one end of the inner tube (10) is connected to the extruder (14).

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