A PE pipe forming device and process with biaxial orientation

Abstract

The present invention relates to the technical field of plastic pipe forming, and specifically relates to a PE pipe forming device and process with biaxial orientation, including a first end body fixedly connected to one end of a middle body and a second end body arranged at the other end of the middle body; a ventilation pipe is fixedly arranged on the first end body along the axial direction of the first end body, a first sealing sleeve for supporting the pipe is sleeved outside the ventilation pipe, the first sealing sleeve is made of a high-temperature resistant elastic material, an expansion cavity is formed between the inner ring side of the first sealing sleeve and the outer wall of the ventilation pipe, and a plurality of ventilation openings communicating with the expansion cavity are arranged on the side wall of the ventilation pipe. The present invention avoids the situation of hot air overflow, ensures both the extrusion force of the first sealing sleeve on the pipe and reduces the energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic pipe forming, and particularly to a forming device and process for PE pipes with biaxial orientation. Background Art

[0002] At present, when preparing biaxially oriented plastic pipes, the pipes are axially stretched by a tractor and radially expanded by expanding parts such as conical parts. However, since the two steps are carried out separately, the preparation cycle is long and the production efficiency is low. At the same time, the introduction of expanding parts such as conical parts will cause friction with the pipe blank, affecting the appearance quality and mechanical properties of the final product.

[0003] Chinese Patent Publication No. CN112848245B discloses a forming die for biaxially oriented plastic pipes, including: a first end body, a middle body, a second end body, a limit block, a fixing block, and a ventilation pipe; the first end body, the middle body, and the second end body are respectively provided with inner cavities along the axis, the first end body, the middle body, and the second end body are detachably connected in sequence along the axis, and the inner cavities communicate with each other in sequence. The diameter of the inner cavity of the middle body is larger than the diameters of the inner cavities of the first end body and the second end body; one end of the limit block is detachably connected to the end of the first end body away from the middle body, and the other end of the limit block extends into the inner cavity of the first end body and has a gap with the inner side wall of the first end body; one end of the fixing block is connected to the end of the second end body away from the middle body, and the other end of the fixing block extends into the inner cavity of the second end body; the ventilation pipe passes through the fixing block and extends into the inner cavity, a plug is provided at one end of the ventilation pipe located in the inner cavity, and a plurality of ventilation holes are provided on the side wall of the ventilation pipe.

[0004] The above solution combines the axial orientation process and the radial orientation process, and completes the forming of biaxially oriented PE pipes through one device. However, when axially orienting and stretching the PE pipes, there is a lack of fixed clamping devices at both ends of the PE pipes. Thus, when axially orienting the PE pipes, the pipes are prone to slipping. At the same time, when radially orienting the pipes, the heated pipes are easily squeezed into the exhaust holes under the action of air pressure, and the exhaust holes are easily blocked after forming and separation. In addition, when radially orienting the pipes, the pipes are radially expanded by inflating, but the gas filled into the inner ring side of the pipes easily overflows from the pipe ends, resulting in a decrease in the expansion rate of the pipes, and at the same time, there is also uneven deformation during the radial orientation of the pipes, thereby affecting the performance of the formed biaxially oriented PE pipes. Summary of the Invention

[0005] To solve the above problems, a forming device and process for PE pipes with biaxial orientation are provided. By sleeving a first sealing sleeve on the ventilation pipe and making the first sealing sleeve made of a high-temperature resistant elastic material, during the forming process, hot air is filled into the forming cavity through the heating unit, and at the same time, the ventilation pipe fills hot air into the expansion cavity through the ventilation ports, so that the inside and outside of the pipe are heated simultaneously. And as the hot air continuously fills the expansion cavity, the expansion cavity continuously expands and squeezes the inner ring side of the pipe, making the diameter of the pipe gradually increase. During this process, the expansion cavity is always in a sealed state, and the hot air in the expansion cavity will not overflow into the forming cavity, avoiding the situation of hot air overflow in the expansion cavity, which not only ensures the extrusion force of the first sealing sleeve on the pipe but also reduces the energy consumption.

[0006] To solve the problems of the prior art, the present invention provides a forming device for PE pipes with biaxial orientation, including a first end body fixedly connected to one end of the middle body and a second end body arranged at the other end of the middle body; a ventilation pipe is fixedly arranged on the first end body along the axis direction of the first end body, and a first sealing sleeve for supporting the pipe is sleeved outside the ventilation pipe. The first sealing sleeve is made of a high-temperature resistant elastic material. The inner ring side of the first sealing sleeve and the outer wall of the ventilation pipe form an expansion cavity, and a plurality of ventilation ports communicating with the expansion cavity are opened on the side wall of the ventilation pipe.

[0007] Preferably, a forming cavity is formed after the first end body, the middle body and the second end body are closed. The forming device further includes a heating unit for heating the forming cavity. The heating unit includes an air inlet opened on the first end body and an air outlet opened on the second end body. The air inlet fills hot air into the forming cavity and discharges it from the air outlet.

[0008] Preferably, an air heater is arranged on one side of the middle body. The air heater has an input end and an output end. The air inlet and the air outlet are respectively connected to the output end and the input end of the air heater. A switch valve and a pressure relief valve are arranged on the upper part of the air heater.

[0009] Preferably, ventilation frames are arranged at both the air inlet and the air outlet. Plugging blocks are slidably arranged on the ventilation frames along the thickness direction of the ventilation frames. When the two plugging blocks rise to the highest position, they can respectively block the air inlet and the air outlet.

[0010] Preferably, a translation column is horizontally movably arranged in the ventilation pipe. A plurality of racks parallel to the extending direction of the translation column are evenly arranged around the translation column on the translation column. A plurality of gears meshing with the racks are rotatably arranged on one side of each rack along the extending direction of the rack. The gears are rotatably arranged on the ventilation ports. A fixing plate is fixedly arranged on the inner ring side wall of the first sealing sleeve. A sliding block is horizontally slidably arranged on the fixing plate. A connecting rod is arranged between the sliding block and the gear. The connecting rod is fixedly connected to the gear and is hinged to the sliding block.

[0011] Preferably, a support shaft is horizontally arranged in the ventilation pipe, the translation column is slidably arranged on the support shaft, an annular ventilation groove is formed between the translation column and the inner wall of the ventilation pipe, and an air pump is arranged at the end of the ventilation pipe.

[0012] Preferably, the middle body includes a first sliding sleeve and a second sliding sleeve. The first sliding sleeve is fixedly connected to the first end body. An extension ring is fixedly arranged at one end of the first sliding sleeve. A collar is fixedly arranged at the end of the second sliding sleeve. The collar is sleeved on the periphery of the extension ring and is slidably matched with the extension ring.

[0013] Preferably, an annular second sealing sleeve is arranged on the inner ring side of the extension ring. The two ends of the second sealing sleeve are respectively fixedly connected to the first sliding sleeve and the second sliding sleeve. The second sealing sleeve is made of a high-temperature resistant elastic material.

[0014] Preferably, an annular groove is formed between the second sealing sleeve and the collar. The extension ring is slidably arranged in the annular groove. A valve body communicating with the annular groove is arranged on the collar. When the extension ring slides out of the annular groove, the valve body injects water into the annular groove.

[0015] The present invention also relates to a forming process for a PE pipe with biaxial orientation. A forming device for a PE pipe with biaxial orientation is adopted, and the specific process is as follows:

[0016] S1. Place the pipe on the ventilation pipe, and then close the end of the second end body with the end of the middle body. The first end body, the middle body and the second end body form a forming cavity.

[0017] S2. Start the heating unit and heat the pipe in the forming cavity. The hot air flows in the forming cavity.

[0018] S3. The ventilation pipe inflates the expansion cavity through the ventilation port. The first sealing sleeve extrudes the inner ring of the pipe, so that the pipe expands in the radial direction, and the middle body drives the pipe to elongate in the axial direction along the horizontal direction.

[0019] The beneficial effects of the present invention compared with the prior art are as follows:

[0020] 1. By sleeving the first sealing sleeve on the ventilation pipe and making the first sealing sleeve made of a high-temperature resistant elastic material, during the forming process, the heating unit fills the forming cavity with hot air, and at the same time the ventilation pipe fills the expansion cavity with hot air through the ventilation port, so that the pipe is heated inside and outside at the same time. And as the hot air is continuously filled into the expansion cavity, the expansion cavity expands continuously and extrudes the inner ring side of the pipe, so that the diameter of the pipe gradually becomes larger. During this process, the expansion cavity is always in a sealed state, and the hot air in the expansion cavity will not overflow into the forming cavity, avoiding the situation of the hot air in the expansion cavity overflowing. This not only ensures the extrusion force of the first sealing sleeve on the pipe, but also reduces the energy consumption.

[0021] 2. By respectively arranging an air inlet and an air outlet on the first end body and the second end body, hot air is filled into the forming cavity through the air inlet, and at the same time, the air in the forming cavity is discharged through the air outlet, so that the hot air flows in the forming cavity. Meanwhile, the inflation cavity is filled with hot air through the air pipe, enabling the pipe to be heated on both sides, accelerating the heating speed of the pipe. By arranging a pressure relief valve on the air heater, when the inflation cavity gradually expands under the inflation action of the air pipe, the inflation cavity gradually enlarges, the forming cavity is gradually squeezed, and the volume in the forming cavity becomes smaller and smaller. During this process, the air squeezed in the forming cavity is discharged through the pressure relief valve arranged on the air heater, ensuring that while the pipe is heated on both sides, the pipe can also be normally radially oriented. At the same time, by arranging blocking blocks on the air inlet and the air outlet, the situation that the material of the pipe blocks the air inlet or the air outlet is avoided. Brief Description of the Drawings

[0022] Figure 1 is a three-dimensional schematic diagram of a PE pipe forming device with biaxial orientation according to the present invention.

[0023] Figure 2 is a side view of a PE pipe forming device with biaxial orientation according to the present invention when a pipe fitting before processing is placed inside.

[0024] Figure 3 is a sectional schematic diagram at A-A in a PE pipe forming device with biaxial orientation according to the present invention. Figure 2 in the [device].

[0025] Figure 4 is a sectional three-dimensional schematic diagram of a PE pipe forming device with biaxial orientation according to the present invention.

[0026] Figure 5 is a [description related to a certain part] in a PE pipe forming device with biaxial orientation according to the present invention. Figure 4 is a partially enlarged schematic diagram at B in the [device].

[0027] Figure 6 is a [description related to a certain part] in a PE pipe forming device with biaxial orientation according to the present invention. Figure 4 is a partially enlarged schematic diagram at C in the [device].

[0028] Figure 7 is a sectional three-dimensional schematic diagram of a PE pipe forming device with biaxial orientation according to the present invention when the pipe processing is completed.

[0029] Figure 8 is a [description related to a certain part] in a PE pipe forming device with biaxial orientation according to the present invention. Figure 7 is a partially enlarged schematic diagram at D in the [device].

[0030] Figure 9 is a [description related to a certain part] in a PE pipe forming device with biaxial orientation according to the present invention.Figure 7 Partial enlarged schematic view at position E.

[0031] Figure 10 It is a Figure 7 Partial enlarged schematic view at position F.

[0032] Figure 11 It is a three-dimensional schematic view of a biaxially oriented PE pipe forming device of the present invention after removing the second sliding sleeve and the heating unit.

[0033] The reference numerals in the figure are:

[0034] 1. First end body; 11. Vent pipe; 111. Vent hole; 12. First sealing sleeve; 13. Hydraulic jaw; 14. Translation column; 141. Rack; 15. Gear; 16. Link; 17. Fixed plate; 18. Slide block; 19. Support shaft; 191. Air pump; 2. Middle body; 21. First sliding sleeve; 211. Extension ring; 22. Second sliding sleeve; 221. Collar; 23. Driving unit; 231. Linear driver; 232. Rangefinder; 24. Second sealing sleeve; 25. Valve body; 3. Second end body; 4. Pipe; 5. Heating unit; 51. Inflation port; 52. Air outlet; 53. Air heater; 54. Switch valve; 55. Pressure relief valve; 56. Ventilation frame; 57. Plugging block. Detailed implementation manners

[0035] In order to further understand the features, technical means, specific purposes and functions achieved by the present invention, the present invention will be further described in detail below with reference to the drawings and specific implementation manners.

[0036] Refer to Figures 1-3 , Figure 7 and Figure 11 : A biaxially oriented PE pipe forming device, comprising a first end body 1 fixedly connected to one end of a middle body 2 and a second end body 3 provided at the other end of the middle body 2; a vent pipe 11 is fixedly provided on the first end body 1 along the axis direction of the first end body 1, a first sealing sleeve 12 for supporting a plurality of pipes 4 is sleeved outside the vent pipe 11, the first sealing sleeve 12 is made of a high-temperature resistant elastic material, an expansion cavity is formed between the inner ring side of the first sealing sleeve 12 and the outer wall of the vent pipe 11, and a plurality of vent holes 111 communicating with the expansion cavity are opened on the side wall of the vent pipe 11.

[0037] In the process of processing the biaxially oriented PE pipe 4, it is necessary to orient the pipe 4 in the radial direction and the axial direction, so that the diameter of the pipe 4 becomes larger and the length becomes longer. The traditional forming method usually needs to be divided into two steps, including radial orientation and axial orientation. When orienting, the pipe 4 needs to be heated. If radial orientation is carried out, the heated pipe 4 needs to be stretched along its radial direction, so that the diameter of the pipe 4 gradually becomes larger; if axial orientation is carried out, the heated pipe 4 needs to be stretched along its axial direction, so that the length of the pipe 4 becomes longer. Therefore, it needs to be processed in two processes, and the processing efficiency is relatively low. In order to improve the efficiency, in the prior art, a device combining radial orientation and axial orientation has been designed. For example, Chinese Patent Publication No. CN112848245B discloses a biaxially oriented plastic pipe forming die. The above patent jointly forms a forming cavity for forming the pipe 4 by a detachable first end body 1, a middle body 2 and a second end body 3, and the length of the middle body 2 in the horizontal direction can be telescoped. An air pipe 11 for supporting the pipe 4 is arranged on the first end body 1. When carrying out the forming operation, the pipe 4 is placed on the air pipe 11, and then the first end body 1, the middle body 2 and the second end body 3 are connected together to form the forming cavity. Subsequently, the air pipe 11 starts to fill the inner ring side of the pipe 4 with high-temperature gas, so that the gas can heat the pipe 4 and at the same time increase the air pressure on one side of the inner ring of the pipe 4, so that the pipe 4 gradually expands. At the same time, the middle body 2 that can be telescoped in the horizontal direction performs axial orientation on the pipe 4, so as to complete the forming process of the biaxially oriented PE pipe 4. However, there is a problem in the above process, that is, there must be a gap between the inner ring of the pipe 4 and the outer wall of the air pipe 11, resulting in air leakage during the inflation process, and a large amount of heated gas escapes. This not only causes the forming rate of the pipe 4 to be slower, but also the large amount of leaked gas will result in higher energy consumption.

[0038] In order to avoid the above situation, the structure of the existing forming device is further optimized, so that the forming rate of the pipe 4 during radial orientation forming is increased, and the continuously overflowing and dissipating heated air can be avoided, reducing the energy consumption. The specific structure and working steps of the forming device are as follows:

[0039] Hydraulic jaws 13 for clamping the ends of the pipe 4 are provided on both the first end body 1 and the second end body 3. The hydraulic jaws 13 are hydraulically driven. During the forming operation, the pipe 4 is inserted from the end of the middle body 2 so that the pipe 4 is sleeved on the ventilation pipe 11. Subsequently, the second end body 3 is closed with the middle body 2. At this time, the first end body 1, the middle body 2, and the second end body 3 together form a forming cavity. The forming device further includes a heating unit 5 for heating the forming cavity. The heating unit 5 can fill the heated air into the forming cavity. In this way, the pipe 4 provided on the ventilation pipe 11 can be heated by the hot air. Subsequently, the ventilation pipe 11 inflates the expansion cavity through the ventilation port 111. Thus, the air pressure in the expansion cavity continuously increases, and the first sealing sleeve 12 squeezes the inner wall of the pipe 4 under the action of the air pressure, so that the diameter of the pipe 4 gradually becomes larger during the extrusion process. Since the middle body 2 can stretch horizontally, and during the forming process, both ends of the pipe 4 will be clamped by the hydraulic jaws 13 in the first end body 1 and the second end body 3 respectively. When the middle body 2 stretches, the first end body 1 and the second end body 3 clamp the pipe 4 and stretch it, realizing that the pipe 4 can be axially oriented while being radially oriented, improving the forming efficiency. And because the present invention covers the first sealing sleeve 12 outside the ventilation pipe 11, the expansion cavity formed by the inner ring side wall of the first sealing sleeve 12 and the ventilation pipe 11 is in a sealed state, avoiding air leakage during the inflation of the expansion cavity, and also avoiding the loss of a large amount of hot air due to air leakage, reducing energy consumption. It should be noted that the air filled into the expansion cavity is also hot air, so that the pipe 4 can be formed faster. The first sealing sleeve 12 can be made of high-temperature resistant elastic materials such as fluororubber and thermoplastic vulcanized rubber.

[0040] By sleeving the first sealing sleeve 12 on the ventilation pipe 11 and making the first sealing sleeve 12 made of high-temperature resistant elastic materials, during forming, the heating unit 5 fills the hot air into the forming cavity, and at the same time the ventilation pipe 11 flushes the hot air into the expansion cavity through the ventilation port 111, so that the inside and outside of the pipe 4 are heated simultaneously. And as the hot air is continuously filled into the expansion cavity, the expansion cavity continuously expands and squeezes the inner ring side of the pipe 4, making the diameter of the pipe 4 gradually become larger. During this process, the expansion cavity is always in a sealed state, and the hot air in the expansion cavity will not overflow into the forming cavity, avoiding the situation of hot air overflow in the expansion cavity, ensuring both the extrusion force of the first sealing sleeve 12 on the pipe 4 and reducing the energy consumption.

[0041] Refer to Figure 3 、 Figure 4 and Figure 7: After the first end body 1, the middle body 2, and the second end body 3 are closed, a forming cavity is formed. The forming device further includes a heating unit 5 for heating the forming cavity. The heating unit 5 includes an air inlet 51 opened on the first end body 1 and an air outlet 52 opened on the second end body 3. The air inlet 51 fills hot air into the forming cavity and discharges it from the air outlet 52.

[0042] In the prior art, when heating the pipe 4, only a single-sided heating method is used to heat the pipe 4, that is, hot air is filled into the inner ring side of the pipe 4 through the ventilation pipe 11, so that while the hot air heats the pipe 4, it can also extrude the pipe 4. However, the heating speed is relatively slow, and the deformation speed of the pipe 4 is also relatively slow. To avoid the above situation, an air inlet 51 and an air outlet 52 are respectively arranged on the first end body 1 and the second end body 3, so that the air inlet 51 fills hot air into the forming cavity, and at the same time the air outlet 52 discharges the air in the forming cavity, enabling the hot air to flow in the forming cavity. At the same time, the ventilation pipe 11 fills hot air into the expansion cavity, causing the pipe 4 to be heated on both sides and accelerating the heating speed of the pipe 4.

[0043] Refer to Figure 1 : An air heater 53 is arranged on one side of the middle body 2. The air heater 53 has an input end and an output end. The air inlet 51 and the air outlet 52 are respectively connected to the output end and the input end of the air heater 53. A switch valve 54 and a pressure relief valve 55 are arranged on the upper part of the air heater 53.

[0044] During the forming process, the expansion cavity gradually expands under the inflation action of the ventilation pipe 11. Thus, the expansion cavity gradually enlarges, the forming cavity is gradually squeezed, and the volume of the forming cavity will become smaller and smaller. During this process, the air squeezed in the forming cavity is discharged through the pressure relief valve 55 arranged on the air heater 53, and at this time the switch valve 54 is in the closed state, ensuring that while the pipe 4 is heated on both sides, the pipe 4 can also be normally radially oriented. When the forming is completed, the ventilation pipe 11 discharges air in the reverse direction, and at this time the switch valve 54 is opened, and external air can rush into the air heater 53.

[0045] Refer to Figure 8 : Ventilation frames 56 are arranged at both the air inlet 51 and the air outlet 52. Plug blocks 57 are slidably arranged on the ventilation frames 56 along the thickness direction of the ventilation frames 56. When the two plug blocks 57 rise to the highest position, they can respectively block the air inlet 51 and the air outlet 52.

[0046] When the ventilation pipe 11 inflates the expansion cavity, the first sealing sleeve 12 squeezes the inner ring side wall of the pipe 4 and gradually increases the diameter of the pipe 4. Since the pipe 4 is heated and softened, blocking blocks 57 are arranged at the air inlet 51 and the air outlet 52 to prevent part of the material of the pipe 4 from being squeezed into the air inlet 51 and the air outlet 52 when the first sealing sleeve 12 radially orients the pipe 4. When the formed pipe 4 is taken out subsequently, it is easy for the material to block the air inlet 51 and the air outlet 52. However, after the blocking blocks 57 are arranged on the air inlet 51 and the air outlet 52, when the pipe 4 expands to the air inlet 51 or the air outlet 52, the blocking block 57 will be pushed into the air inlet 51 or the air outlet 52 by the pipe 4. In this way, the softened pipe 4 cannot be squeezed into the air inlet 51 or the air outlet 52, avoiding the situation where the material of the pipe 4 blocks the air inlet 51 or the air outlet 52.

[0047] Refer to Figure 5 、 Figure 6 and Figure 9 : A translation column 14 is horizontally movably arranged in the ventilation pipe 11. A plurality of racks 141 parallel to the extending direction of the translation column 14 are evenly arranged around the translation column 14 on the translation column 14. A plurality of gears 15 meshing with the racks 141 are rotatably arranged on one side of each rack 141 along the extending direction of the rack 141. The gears 15 are rotatably arranged on the ventilation ports 111. A fixing plate 17 is fixedly arranged on the inner ring side wall of the first sealing sleeve 12. A sliding block 18 is horizontally slidably arranged on the fixing plate 17. A connecting rod 16 is arranged between the sliding block 18 and the gear 15. The connecting rod 16 is fixedly connected with the gear 15, and the connecting rod 16 is hinged with the sliding block 18.

[0048] When the ventilation pipe 11 inflates the expansion cavity, the first sealing sleeve 12 gradually expands. At this time, the fixing plate 17 fixedly arranged on the first sealing sleeve 12 moves synchronously with the first sealing sleeve 12. The fixing plate 17 drives the connecting rod 16 to rotate through the sliding block 18, and further makes the gear 15 fixedly connected with the connecting rod 16 rotate. Since all the gears 15 mesh with the racks 141 on the translation column 14, all the gears 15 are in a synchronous rotation state, ensuring the uniformity of the outer side of the first sealing sleeve 12 during expansion, and further ensuring the uniformity of the pipe 4 during the radial orientation process.

[0049] Refer to Figure 5 : A support shaft 19 is horizontally arranged in the ventilation pipe 11. The translation column 14 is slidably arranged on the support shaft 19. An annular ventilation groove exists between the translation column 14 and the inner wall of the ventilation pipe 11. An air pump 191 is arranged at the end of the ventilation pipe 11.

[0050] Through the guidance of the support shaft 19 for the translation column 14, the translation column 14 can stably slide along the horizontal direction.

[0051] Refer toFigure 7 and Figure 10 : The middle body 2 includes a first sliding sleeve 21 and a second sliding sleeve 22. The first sliding sleeve 21 is fixedly connected to the first end body 1. An extension ring 211 is fixedly provided at one end of the first sliding sleeve 21. A collar 221 is fixedly provided at the end of the second sliding sleeve 22. The collar 221 is sleeved on the periphery of the extension ring 211 and is in sliding fit with the extension ring 211.

[0052] A driving unit 23 for driving the relative movement of the two is arranged between the first sliding sleeve 21 and the second sliding sleeve 22. The driving unit 23 includes a linear driver 231 and a rangefinder 232. The linear driver 231 is horizontally arranged on the first sliding sleeve 21 or the second sliding sleeve 22. If the linear driver 231 is arranged on the first sliding sleeve 21, the output end of the linear driver 231 is fixedly connected to the second sliding sleeve 22. If the linear driver 231 is arranged on the second sliding sleeve 22, its output end is fixedly connected to the first sliding sleeve 21. The rangefinder 232 is horizontally arranged on the first sliding sleeve 21 or the second sliding sleeve 22. When the rangefinder 232 is arranged on the first sliding sleeve 21, the end of the rangefinder 232 is horizontally oriented towards the second sliding sleeve 22. Similarly, when the rangefinder 232 is arranged on the second sliding sleeve 22, the end of the rangefinder 232 is horizontally oriented towards the first sliding sleeve 21. The rangefinder 232 is used to measure the length after the first sliding sleeve 21 and the second sliding sleeve 22 are stretched. When the first sliding sleeve 21 and the second sliding sleeve 22 are extended to a specified length, they stop moving.

[0053] Refer to Figure 10 : A ring-shaped second sealing sleeve 24 is arranged on the inner ring side of the extension ring 211. Both ends of the second sealing sleeve 24 are fixedly connected to the first sliding sleeve 21 and the second sliding sleeve 22 respectively. The second sealing sleeve 24 is made of a high-temperature resistant elastic material.

[0054] By arranging the second sealing sleeve 24 between the first sliding sleeve 21 and the second sliding sleeve 22, when the first sliding sleeve 21 and the second sliding sleeve 22 slide relative to each other, the gap that appears at the adjacent ends of the first sliding sleeve 21 and the second sliding sleeve 22 can be blocked by the second sealing sleeve 24, preventing the pipe 4 from being squeezed into the gap during the radial orientation process, resulting in deformation of the finally formed pipe 4.

[0055] Refer to Figure 10 : An annular groove is formed between the second sealing sleeve 24 and the collar 221. The extension ring 211 is slidably arranged in the annular groove. A valve body 25 communicating with the annular groove is arranged on the collar 221. When the extension ring 211 slides out of the annular groove, the valve body 25 injects water into the annular groove.

[0056] When the extension ring 211 slides out of the annular groove, a negative pressure is generated in the annular groove. At this time, the valve body 25 opens, and water flows through the valve body 25 into the annular groove. When the first sliding sleeve 21 and the second sliding sleeve 22 stop moving, the radial orientation of the pipe 4 has not ended, that is, at this time, the pipe 4 has not yet contacted the inner ring side wall of the first sliding sleeve 21 and the inner ring side wall of the second sliding sleeve 22. Subsequently, the valve body 25 closes. When the pipe 4 continues to expand, the water in the annular groove provides support for the pipe 4, preventing the pipe 4 from deforming the second sealing sleeve 24 during the expansion process and avoiding deformation of the pipe 4 after molding.

[0057] Refer to Figures 1-11 : The present invention also relates to a forming process for a PE pipe with biaxial orientation, using a forming device for a PE pipe with biaxial orientation. The specific process is as follows:

[0058] S1. Place the pipe 4 on the ventilation pipe 11, and then close the end of the second end body 3 with the end of the middle body 2. The first end body 1, the middle body 2, and the second end body 3 form a forming cavity;

[0059] S2. The heating unit 5 is started and heats the pipe 4 in the forming cavity, and hot air flows in the forming cavity;

[0060] S3. The ventilation pipe 11 inflates the expansion cavity through the ventilation port 111, and the first sealing sleeve 12 squeezes the inner ring of the pipe 4, causing the pipe 4 to expand in the radial direction, and the middle body 2 drives the pipe 4 to elongate in the axial direction along the horizontal direction.

[0061] Working principle: When carrying out the forming operation, the pipe 4 is inserted from the end of the middle body 2 so that the pipe 4 is sleeved on the ventilation pipe 11. Subsequently, the second end body 3 is closed with the middle body 2. At this time, the first end body 1, the middle body 2 and the second end body 3 jointly form a forming cavity. The forming device further includes a heating unit 5 for heating the forming cavity. The heating unit 5 can fill the heated air into the forming cavity. In this way, the pipe 4 arranged on the ventilation pipe 11 can be heated by the hot air. Subsequently, the ventilation pipe 11 inflates the expansion cavity through the ventilation port 111. In this way, the air pressure in the expansion cavity continuously rises, and the first sealing sleeve 12 squeezes the inner wall of the pipe 4 under the action of the air pressure, so that the diameter of the pipe 4 gradually becomes larger during the extrusion process. Since the middle body 2 can expand and contract in the horizontal direction, and during the forming process, both ends of the pipe 4 will be clamped by the hydraulic jaws 13 in the first end body 1 and the second end body 3 respectively. When the middle body 2 stretches, the first end body 1 and the second end body 3 clamp and stretch the pipe 4, realizing that the pipe 4 can be axially oriented while being radially oriented, improving the forming efficiency. And because the present invention covers the first sealing sleeve 12 outside the ventilation pipe 11, the expansion cavity formed by the inner ring side wall of the first sealing sleeve 12 and the ventilation pipe 11 is in a sealed state, avoiding air leakage during the inflation of the expansion cavity, and also avoiding the loss of a large amount of hot air due to air leakage, reducing energy consumption. It should be noted that the air filled into the expansion cavity is also hot air, so that the pipe 4 can be formed faster. The first sealing sleeve 12 can be made of high-temperature resistant elastic materials such as fluororubber and thermoplastic vulcanized rubber.

[0062] The above embodiments only represent one or several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A PE pipe forming device with biaxial orientation, comprising a first end body (1) fixedly connected to one end of a middle body (2) and a second end body (3) arranged at the other end of the middle body (2); It is characterized in that A ventilation pipe (11) is fixedly arranged on the first end body (1) along the axis direction of the first end body (1). A first sealing sleeve (12) for supporting a pipe (4) is sleeved outside the ventilation pipe (11). The first sealing sleeve (12) is made of a high-temperature resistant elastic material. An expansion cavity is formed between the inner ring side of the first sealing sleeve (12) and the outer wall of the ventilation pipe (11). A plurality of ventilation openings (111) communicating with the expansion cavity are arranged on the side wall of the ventilation pipe (11); A forming cavity is formed after the first end body (1), the middle body (2) and the second end body (3) are closed. The forming device further comprises a heating unit (5) for heating the forming cavity. The heating unit (5) comprises an air inlet (51) arranged on the first end body (1) and an air outlet (52) arranged on the second end body (3). The air inlet (51) fills hot air into the forming cavity and discharges it from the air outlet (52); An air heater (53) is arranged on one side of the middle body (2). The air heater (53) has an input end and an output end. The air inlet (51) and the air outlet (52) are respectively connected to the output end and the input end of the air heater (53). A switching valve (54) and a pressure relief valve (55) are arranged on the upper part of the air heater (53); Ventilation frames (56) are arranged at both the air inlet (51) and the air outlet (52). A blocking block (57) is slidably arranged on the ventilation frame (56) along the thickness direction of the ventilation frame (56). When the two blocking blocks (57) rise to the highest position, they can block the air inlet (51) and the air outlet (52) respectively.

2. The forming device for PE pipes with biaxial orientation according to claim 1, characterized in that, A translation column (14) is horizontally movably arranged in the ventilation pipe (11). A plurality of racks (141) parallel to the extending direction of the translation column (14) are uniformly arranged around the translation column (14) on the translation column (14). A plurality of gears (15) meshing with the rack (141) are rotatably arranged on one side of each rack (141) along the extending direction of the rack (141). The gears (15) are rotatably arranged on the ventilation openings (111). A fixing plate (17) is fixedly arranged on the inner ring side wall of the first sealing sleeve (12). A sliding block (18) is horizontally slidably arranged on the fixing plate (17). A connecting rod (16) is arranged between the sliding block (18) and the gear (15). The connecting rod (16) is fixedly connected to the gear (15), and the connecting rod (16) is hinged to the sliding block (18).

3. The PE pipe forming device with biaxial orientation according to claim 2, characterized in that, A support shaft (19) is horizontally arranged in the ventilation pipe (11). The translation column (14) is slidably arranged on the support shaft (19). An annular ventilation groove exists between the translation column (14) and the inner wall of the ventilation pipe (11). An air pump (191) is arranged at the end of the ventilation pipe (11).

4. A PE pipe forming device with biaxial orientation according to claim 1, characterized in that, The middle body (2) includes a first sliding sleeve (21) and a second sliding sleeve (22). The first sliding sleeve (21) is fixedly connected to the first end body (1). An extension ring (211) is fixedly arranged at one end of the first sliding sleeve (21). A collar (221) is fixedly arranged at the end of the second sliding sleeve (22). The collar (221) is sleeved on the periphery of the extension ring (211) and is in sliding fit with the extension ring (211).

5. A PE pipe forming device with biaxial orientation according to claim 4, characterized in that, A ring-shaped second sealing sleeve (24) is arranged on the inner ring side of the extension ring (211). Two ends of the second sealing sleeve (24) are respectively fixedly connected to the first sliding sleeve (21) and the second sliding sleeve (22). The second sealing sleeve (24) is made of a high-temperature resistant elastic material.

6. The forming device for a PE pipe with biaxial orientation according to claim 5, characterized in that, An annular groove is formed between the second sealing sleeve (24) and the collar (221). The extension ring (211) is slidably arranged in the annular groove. A valve body (25) communicating with the annular groove is arranged on the collar (221). When the extension ring (211) slides out of the annular groove, the valve body (25) injects water into the annular groove.

7. A forming process for a PE pipe with biaxial orientation, which uses a forming device for a PE pipe with biaxial orientation described in any one of claims 1-6, characterized in that, The specific process is as follows: S1. Place the pipe (4) on the ventilation pipe (11), and then close the end of the second end body (3) with the middle body (2). The first end body (1), the middle body (2) and the second end body (3) form a molding cavity. S2. Heat the pipe (4) in the molding cavity, and the hot air flows in the molding cavity. S3. The ventilation pipe (11) inflates the expansion cavity through the ventilation port (111). The first sealing sleeve (12) extrudes the inner ring of the pipe (4), so that the pipe (4) expands in the radial direction, and the middle body (2) drives the pipe (4) to elongate in the axial direction along the horizontal direction.

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