Pipe extruder for producing PE water pipes

Abstract

The present application relates to the technical field of pipe extrusion molding, in particular to a pipe extruder for producing PE water pipes, which comprises an extrusion host and a sizing sleeve arranged downstream of the extrusion outlet, and a supporting transition piece arranged between the two, the supporting transition piece comprising a supporting pipe ring forming a pipe blank passage inside; the upstream end of the pipe blank passage forms a die separation expansion section, the downstream end of the die separation expansion section forms an annular flange portion protruding inward, the annular flange portion successively forms an upstream inclined surface, a circular arc top portion and a downstream inclined surface provided with a plurality of air outlet slots; a plurality of partitioned air cavities are arranged in the pipe wall of the supporting pipe ring, the partitioned air cavities are connected to an external air source through an air inlet throttling structure, and are connected to corresponding air outlet slots through independent air outlet pipelines, and an air pressure detection sensor is arranged in each partitioned air cavity; the present application uses the air discharged from the air outlet slots to support the hot pipe blank, and identifies the radial deviation of the pipe blank according to the pressure change of each partitioned air cavity, so as to reduce the scratching, adhesion and surface damage of the pipe blank before entering the sizing sleeve.

Description

Technical Field

[0001] This invention relates to the field of pipe extrusion molding technology, and more particularly to a pipe extruder for producing PE water pipes. Background Technology

[0002] Polyethylene water pipes are plastic pipes made primarily of polyethylene resin. They are characterized by corrosion resistance, light weight, and ease of connection, and are widely used in building water supply, municipal water supply, and agricultural irrigation. They are typically produced using a continuous extrusion process.

[0003] Pipe extruders used to produce PE water pipes typically include an extruder main unit, a die head, a sizing and cooling device, and a traction device. During production, polyethylene raw materials are conveyed and plasticized in the extruder main unit and then enter the die head. They are continuously extruded from the annular extrusion port of the die head to form a hot pipe blank. After passing through the transition area between the extrusion port and the sizing sleeve, the pipe blank enters the sizing sleeve. Then, with the help of vacuum sizing, cooling, and traction, the pipe is formed.

[0004] Because the tube blank that has just left the extrusion port is still in a soft state with a high temperature and has not yet been shaped, and there is an interval between the extrusion port and the sizing sleeve for the tube blank to expand and be transported after leaving the die, the tube blank is prone to sagging or radial displacement before entering the sizing sleeve. This can cause the tube blank to rub against or stick to the surrounding structure of the transition area, or prevent the tube blank from accurately aligning with the inlet of the sizing sleeve, thereby affecting the surface quality of the pipe and the subsequent sizing effect. Summary of the Invention

[0005] The main objective of this invention is to provide a pipe extruder for producing PE water pipes, in order to solve the technical problem in the prior art that hot pipe blanks are prone to sagging or radial displacement between the extrusion port and the sizing sleeve, which leads to scraping, adhesion and difficulty in timely identification of the radial displacement position.

[0006] To achieve the above objectives, the present invention provides a pipe extruder for producing PE water pipes, including an extrusion host, a sizing sleeve provided downstream of the extrusion port of the extrusion host, a support transition member provided between the extrusion port and the sizing sleeve, the support transition member including a support tube ring, one end of the support tube ring being connected to the extrusion port, and a tube blank channel for tube blank to pass through being formed inside the support tube ring.

[0007] One end of the tube blank channel connected to the extrusion port forms a die-off expansion section. An inwardly protruding annular flange is formed at the downstream end of the die-off expansion section. The annular flange forms an upstream slope, an arc top, and a downstream slope in sequence along the tube blank conveying direction. The downstream slope has multiple air outlet slits.

[0008] Multiple circumferentially spaced and isolated partitioned air chambers are provided inside the pipe wall of the bearing ring. Each partitioned air chamber has an air inlet throttling device that is connected to an external air source. Each partitioned air chamber is connected to the corresponding air outlet through an independent air outlet pipeline. A pressure detection sensor is also provided in each partitioned air chamber.

[0009] Furthermore, the vent seam extends in an arc shape along the circumference of the annular flange, and the opening of the vent seam is located on the downstream slope near the top of the arc.

[0010] Furthermore, the upstream end of the mold expansion section is connected to the extrusion port, and its inner diameter gradually increases from the upstream end to the downstream end.

[0011] Furthermore, a plurality of supporting roller groups corresponding to the positions of the air outlet seams are provided circumferentially at the top of the arc, and part of the outer peripheral surface of each supporting roller group protrudes into the tube blank channel.

[0012] Furthermore, a cavity is formed within the tube wall of the supporting tube ring and radially outward from the top of the arc, encircling the tube blank channel, and the supporting roller assembly is embedded in this cavity.

[0013] Furthermore, the cavity is also provided with a plurality of scraping parts corresponding to the supporting roller assembly, and the scraping part of the scraping part contacts the outer peripheral surface of the corresponding supporting roller located in the cavity.

[0014] At the bottom of the cavity, there is also a discharge port that extends to the outside of the support ring.

[0015] Furthermore, the end of the bearing ring away from the extrusion port is axially spaced from the sizing sleeve, and a deflector corresponding to the air outlet slit is provided circumferentially on the inner wall of the downstream end of the billet channel;

[0016] The deflecting guide includes a connecting plate, a straight section, and an inclined section connected in sequence. The connecting plate is connected to the inner wall of the tube blank channel. The straight section is connected to the connecting plate and extends upstream of the tube blank channel. The inclined section is connected to one end of the straight section and is inclined towards the inner wall of the tube blank channel in the upstream direction. The free end of the inclined section is spaced from the inner wall of the tube blank channel.

[0017] A return air zone is formed between the straight section and the inclined section and the inner wall of the tube blank channel.

[0018] Furthermore, the wall surface of the straight section facing the return air zone is provided with a semi-conical guide section, the tip of the semi-conical guide section facing the free end of the inclined section, and its conical surface gradually extends to both sides of the circumferential direction of the return air zone along the tube blank conveying direction, so as to guide the airflow entering the return air zone from one side of the free end of the inclined section to both sides for discharge.

[0019] Furthermore, it also includes a frame, and the sizing sleeve is mounted on the frame via a displacement adjustment assembly, the displacement adjustment assembly being able to drive the sizing sleeve to move radially;

[0020] The displacement adjustment components are electrically connected to the air pressure detection sensors respectively, and are used to adjust the radial position of the sizing sleeve according to the detection signals of each air pressure detection sensor.

[0021] Furthermore, the displacement adjustment assembly includes a first radial drive member and a second radial drive member with driving directions perpendicular to each other. The first radial drive member is mounted on the frame, and the second radial drive member is disposed on the drive portion of the first radial drive member. The sizing sleeve is connected to the drive portion of the second radial drive member.

[0022] Compared with the prior art, the beneficial effects that the present invention can achieve include at least the following:

[0023] 1. The present invention provides a support ring between the extrusion port and the sizing sleeve, and uses the die-off expansion section to provide space for the radial expansion of the tube blank after it leaves the die. The support gas is output to the outer wall of the tube blank through the gas outlet slit on the downstream slope of the annular flange, thereby reducing the scraping, adhesion and surface damage of the hot tube blank caused by sagging or radial displacement.

[0024] 2. The present invention uses mutually isolated partitioned air chambers and independent air outlet pipelines to convert the gap changes between the tube blank and the air outlets at different circumferential positions into corresponding air pressure changes, so as to identify the radial offset of the tube blank. The displacement adjustment component drives the sizing sleeve to move radially, so that the inlet position of the sizing sleeve is adapted to the actual conveying position of the tube blank.

[0025] 3. The present invention provides a set of supporting rollers at the top of the arc of the annular flange, so that the tube blank with large offset forms a support mode with rolling contact as the main method, thereby reducing the dragging effect caused by relative sliding; at the same time, the scraping parts and the impurity discharge port in the cavity clean the residual material on the surface of the supporting rollers, so as to maintain the rotation state of the supporting rollers.

[0026] 4. The present invention uses a deflecting guide to direct the supporting gas flowing to the downstream end of the tube blank channel into the return air zone and turn it to the circumferential side for discharge, thereby reducing the situation where the gas flows to the sizing sleeve inlet in a concentrated manner. The semi-conical guide section is used to guide the gas to both sides of the return air zone, thereby reducing the impact of downstream pressure changes on the exhaust state of the outlet seam and the results of zoned air pressure detection. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale.

[0028] Figure 1 This is a schematic diagram of the overall structure of the extruder provided in Embodiment 1 of the present invention;

[0029] Figure 2 This is a front view of the extruder provided in Embodiment 1 of the present invention;

[0030] Figure 3 This is a partial cross-sectional view of the bearing ring provided in Embodiment 1 of the present invention;

[0031] Figure 4 This is a partially enlarged structural schematic diagram of the supporting roller provided in Embodiment 1 of the present invention;

[0032] Figure 5 This is a partial cross-sectional view of the bearing tube ring provided in Embodiment 1 of the present invention, formed by extrusion molding of the tube blank;

[0033] Figure 6 This is a schematic diagram of the structure of the deflector provided in Embodiment 1 of the present invention;

[0034] Figure 7 This is a schematic diagram of a preferred embodiment of the scraper provided in Embodiment 2 of the present invention.

[0035] In the above figures, the reference numerals are as follows: 1. Extrusion host; 11. Extrusion port; 2. Sizing sleeve; 3. Supporting transition piece; 31. Supporting tube ring; 311. Billet channel; 312. Annular flange; 313. Air outlet; 32. Zoned air chamber; 321. Air inlet throttling piece; 322. Air pressure detection sensor; 33. Supporting roller assembly; 331. Triggering protrusion; 332. Receiving part; 34. Scraper; 341. Fixing part; 342. Elastic connection part; 343. Scraper; 35. Reversing guide piece; 351. Connecting plate; 352. Straight part; 353. Inclined part; 354. Semi-conical guide piece; 4. Frame; 41. First radial drive piece; 42. Second radial drive piece; 5. Billet.

[0036] The realization of the objective, functional features and advantages of the present invention will be further explained below with reference to the embodiments and the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] Furthermore, if the embodiments of the present invention involve descriptions using terms such as "first," "second," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Moreover, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0041] Example 1:

[0042] It should be noted that during the PE pipe extrusion molding process, after the molten pipe blank 5 is extruded from the extrusion port 11, its outer diameter expands to a certain extent compared to the extrusion due to the inherent expansion characteristics of the polymer melt after extrusion. Therefore, existing extruders usually need to maintain a certain transition gap between the extrusion port 11 and the sizing sleeve 2 to accommodate the expansion of the pipe blank 5 after extrusion and to isolate the interference of the high temperature of the die on the sizing section. However, the pipe blank 5 in this transition gap is at a high temperature and has not yet been shaped. Moreover, this area lacks support for the pipe blank 5, and the pipe blank 5 is in a suspended state. It is prone to sagging due to its own weight, or radial displacement due to extrusion and traction fluctuations. This can lead to rubbing or adhesion with the surrounding mechanisms in the transition area, or make it difficult for the pipe blank 5 to maintain coaxiality with the sizing sleeve 2 when it enters the sizing sleeve 2, ultimately affecting the surface quality of the pipe and the sizing molding effect.

[0043] Therefore, this embodiment provides a pipe extruder for producing PE water pipes. Specifically, it utilizes a support transition member 3 with a die expansion section and a special air outlet 313 set between the extrusion port 11 and the sizing sleeve 2, in conjunction with the internal partitioned air chamber 32 and air pressure detection sensor 322 to monitor the air pressure signal in real time. This solves the technical problem in conventional extrusion production that it is difficult to provide non-destructive flexible support and position monitoring for the high-temperature soft pipe blank 5, which leads to easy damage to the surface of the extruded pipe and uncontrollable molding quality.

[0044] It should also be noted that in this embodiment, upstream and downstream refer to the conveying direction of the tube blank 5. That is, the side closer to the extrusion port 11 of the extruder 1 is upstream, and the side closer to the sizing sleeve 2 is downstream. The radial direction refers to the direction perpendicular to the axis of the tube blank channel 311, and the circumferential direction refers to the direction around the axis of the tube blank channel 311.

[0045] For an example, please refer to Figure 1 and Figure 2As shown, the extruder structure proposed in this embodiment includes an extrusion host 1, which is used to complete the feeding, conveying, plasticizing, and extrusion of polyethylene raw materials. It can adopt an existing single-screw plastic extrusion structure and includes a barrel, an extrusion screw rotatably disposed in the barrel, a hopper disposed on the feed side of the barrel, a heating section disposed along the barrel, and an extrusion port 11 located at the discharge end of the barrel. A sizing sleeve 2 is provided downstream of the extrusion port 11 of the extrusion host 1. The sizing sleeve 2 is used to receive the tube blank 5 conveyed downstream from the extrusion port 11. A support transition member 3 is provided between the extrusion port 11 and the sizing sleeve 2. The support transition member 3 includes... The support ring 31 can be formed by processing heat-resistant metal material. Its upstream end is provided with a connecting flange adapted to the extruder head and is detachably connected by fasteners. A heat-resistant seal can be provided between the connecting flange and the extrusion port 11. One end of the support ring 31 is connected to the extrusion port 11, and its interior is connected along the conveying direction of the tube blank 5 to form a tube blank channel 311. The tube blank channel 311 is used to accommodate the tube blank 5 that has just left the extrusion port 11 and to provide continuous internal passage space for the tube blank 5 to move towards the sizing sleeve 2. The axis of the tube blank channel 311 can be basically coincident with the axis of the extrusion port 11 in the initial installation state of the equipment.

[0046] Further integration Figure 3 and Figure 4 It can be seen that a die-off expansion section is formed at one end of the tube blank channel 311 connected to the extrusion port 11. The die-off expansion section is used to accommodate the radial expansion generated after the tube blank 5 leaves the extrusion port 11. At the downstream end of the die-off expansion section, there is an annular flange portion 312 protruding into the tube blank channel 311. The annular flange portion 312 forms an upstream slope, a circular arc top, and a downstream slope in sequence along the tube blank 5 conveying direction. The upstream slope is used to form a continuous transition between the die-off expansion section and the circular arc top. The circular arc top constitutes the annular flange portion 312 with the greatest degree of protrusion towards the axis of the tube blank channel 311. The part adopts an arc-shaped structure without sharp corners to reduce the possibility of the flange edge scratching the tube blank 5 when the tube blank 5 undergoes a large radial displacement. The downstream slope extends from the top of the arc to the downstream side of the tube blank channel 311 and provides an outlet position for the supporting gas to enter the space between the outer wall of the tube blank 5 and the inner wall of the supporting ring 31. That is, multiple air outlet slits 313 are opened on the downstream slope. Each air outlet slit 313 is arranged at intervals along the circumference of the annular flange 312 and corresponds to different circumferential positions on the outer circumference of the tube blank 5, so that the supporting gas can be discharged into the tube blank channel 311 from different directions and act on the outer wall of the tube blank 5.

[0047] The pipe wall of the support ring 31 is also provided with a plurality of circumferentially spaced and mutually isolated partitioned air chambers 32. Each partitioned air chamber 32 corresponds to a circumferential region of the billet channel 311. Adjacent partitioned air chambers 32 are separated by solid cavity walls, so that pressure changes in one partitioned air chamber 32 will not be directly transmitted to the adjacent partitioned air chambers 32 through the inside of the support ring 31. For example, four partitioned air chambers 32 can be set and correspond to the upper side, lower side, left side and right side of the billet channel 311 respectively. When the diameter of the billet 5 is large or it is necessary to further distinguish the inclination direction, six or eight partitioned air chambers 32 can also be set circumferentially. Each partitioned air chamber 32 corresponds to an air outlet slit 313, and the two are set in the same circumferential order.

[0048] Each of the partitioned air chambers 32 is connected to an external air source (such as an air compressor or a compressed air supply network at the production site) through an intake throttling structure. The intake throttling structure is used to limit the gas flow rate from the external air source into the corresponding partitioned air chamber 32, so that the partitioned air chamber 32 forms an internal pressure that is affected by both the intake volume and the exhaust resistance of the corresponding exhaust slit 313 under continuous air supply. The intake throttling structure can be an intake throttling orifice with a fixed flow area, or it can be an intake throttling valve that can adjust the effective flow area. When an intake throttling valve is used, an independent intake throttling valve is set on the air supply branch of each partitioned air chamber 32. The intake throttling valve can be a needle valve or a miniature gas flow regulating valve. Each partitioned air chamber 32 is connected to the corresponding exhaust slit 313 through an independent exhaust pipeline, so that each partitioned air chamber 32 forms an independent exhaust path, and the change in exhaust resistance at the corresponding circumferential position can be reflected in the internal pressure of the corresponding partitioned air chamber 32.

[0049] Each of the partitioned air chambers 32 is also provided with a pressure detection sensor 322. The pressure detection sensor 322 is used to detect the pressure inside the air chamber 32 of its partition and outputs a pressure detection signal corresponding to each circumferential position, so as to determine whether the tube blank 5 is moving closer to a certain circumferential position.

[0050] For example, the type of air pressure detection sensor 322 can be a commercially available thin-film pressure sensor, piezoresistive pressure sensor or ceramic capacitive pressure sensor. Each air pressure detection sensor 322 is arranged in a one-to-one correspondence with each partition air cavity 32 along the circumference of the support ring 31. The sensor body is fixed to the inner surface of the radial outer cavity wall of the corresponding partition air cavity 32, and its pressure detection end faces the inside of the partition air cavity 32. The signal wire is led out to the outside of the support ring 31 through the sealed wire hole opened on the tube wall of the support ring 31.

[0051] For example, in a specific production process, when the gas output from the external air source (such as compressed air that has been filtered, degreased and pressure stabilized) enters the corresponding partitioned air chamber 32 through each air intake throttling device 321, it is then transported to the corresponding air outlet 313 by each independent air outlet pipeline, and discharged from the air outlet 313 into the space between the downstream inclined surface and the outer wall of the tube blank 5 and discharged downstream along the conveying direction of the tube blank 5; when the tube blank 5 is within the allowable center range of the tube blank channel 311, exhaust gaps are maintained between the outer wall of the tube blank 5 and the air outlet 313 at each circumferential position and the adjacent inner wall. Each partitioned air chamber 32 maintains the corresponding working pressure during continuous air intake and exhaust. The gas discharged from the lower side of the tube blank 5 forms an upward supporting effect on the tube blank 5, and the gas discharged from the other circumferential positions is used to limit the tube blank 5 from continuing to approach the inner wall of the corresponding support tube ring 31.

[0052] When the tube blank 5 shifts to a certain circumferential position due to its own weight or changes in the extrusion conveying state, the local exhaust gap between the outer wall of the tube blank 5 and the exhaust slit 313 at that position decreases accordingly. At this time, the resistance to the gas being discharged from the exhaust slit 313 increases to a certain extent. As the external air source continues to supply air to the corresponding partition air chamber 32 through the air inlet throttling device 321, the pressure inside the partition air chamber 32 will increase relative to when the tube blank 5 is in the center. At the same time, the exhaust gap on the side of the tube blank 5 that is shifted in the opposite direction increases relatively, and the pressure change trend inside the corresponding partition air chamber 32 is different from that on the side closer to the tube blank 5. By comparing the detection results of the air pressure detection sensor 322 at different circumferential positions, it can be determined that the tube blank 5 has shifted to the circumferential position corresponding to the increase in pressure.

[0053] It is also understandable that the detection process of this scheme uses the change in the gap between the outer wall of the tube blank 5 and the air outlet 313 to change the exhaust resistance of the corresponding air outlet path. Therefore, the air pressure detection sensor 322 does not need to be in direct contact with the hot tube blank 5, nor does it need to set identification marks on the surface of the tube blank 5. Thus, it can detect the radial position status of the tube blank 5 during continuous extrusion and conveying, ensuring that the detection results are not affected by other factors (such as the temperature of the hot tube blank 5).

[0054] Based on this, this embodiment utilizes the supporting gas discharged from each air outlet 313 to support the hot tube blank 5 in sections, so that the tube blank 5 usually maintains a distance from the fixed inner wall of the supporting tube ring 31 when passing through the area where the annular flange portion 312 is located, thereby reducing the possibility of the tube blank 5 being scratched, stuck, and damaged on the surface due to sagging or displacement before entering the sizing sleeve 2; in addition, each section of air chamber 32 is isolated from each other and is connected to the corresponding air outlet 313 through an independent air outlet pipeline, so that the gap changes generated by the tube blank 5 at different circumferential positions can form mutually distinguishable air pressure detection results, thereby identifying the radial displacement direction of the tube blank 5 while supporting it, and providing a detection basis for subsequent adjustment of the relative position between the tube blank 5 and the inlet of the sizing sleeve 2.

[0055] In this embodiment, to further optimize the stability of airflow supporting the soft tube blank 5, for example, the air outlet 313 extends in an arc shape along the circumference of the annular flange 312, and the opening of the air outlet 313 is selectively arranged on the downstream inclined surface and close to the top of the arc; and multiple arc-shaped air outlets 313 are adjacent to each other in the circumference, together forming a strip-shaped air outlet array around the outer periphery of the tube blank 5 inside the tube blank channel 311.

[0056] During the actual transport of the tube blank 5, the supporting gas delivered by the partitioned air chamber 32 reaches the corresponding air outlet 313 through an independent air outlet pipeline, and is discharged into the gap between the downstream inclined surface and the outer wall of the tube blank 5 along the circumferential length occupied by the arc-shaped seam. This allows the gas to be distributed and act on the outer wall of the tube blank 5 within the corresponding circumferential section and discharged downstream along the transport direction of the tube blank 5, so as to achieve the uniform application of the supporting airflow lifting force to the outer wall of the tube blank 5. Since the air outlet 313 is located near the top of the arc, its air outlet position is adjacent to the annular flange 312. In the area protruding significantly into the tube blank channel 311, as the tube blank 5 approaches this circumferential position, the local exhaust gap formed between the outer wall of the tube blank 5 and the exhaust vent 313 decreases, thereby reducing the effective exhaust area of ​​the exhaust vent 313. This increases the exhaust resistance of the corresponding exhaust path, which in turn increases the pressure inside the corresponding partitioned air chamber 32 and creates a pressure difference with other partitioned air chambers 32 in the circumferential position. This facilitates the timely identification of the radial offset of the tube blank 5 by the air pressure detection sensor 322.

[0057] In this embodiment, as Figure 3 and Figure 5 As shown, the upstream end of the mold expansion section is connected to the extrusion port 11, and its inner diameter gradually increases from the upstream end to the downstream end.

[0058] For example, the extrusion expansion section can be a gradually expanding cavity with a conical or smooth arc surface on the inner wall. Its upstream inner wall is smoothly connected to the outer periphery of the extrusion port 11, and its downstream end is connected to the upstream inclined surface of the annular flange 312. When the tube blank 5 leaves the extrusion port 11 and generates radial expansion, the gradually increasing cavity space can provide a corresponding passage allowance for the change of the outer diameter of the tube blank 5, reduce the situation where the tube blank 5 contacts the cavity wall in advance during the expansion process, and allow the tube blank 5 to continue to be transported to the area where the annular flange 312 is located. The degree of expansion of the extrusion expansion section can be set according to the size of the extrusion port 11, the tube specifications, and the expected expansion amount of the tube blank 5.

[0059] It should be noted that when the extrusion or traction state of the tube blank 5 fluctuates briefly, the tube blank 5 may still experience a large instantaneous sag or radial displacement in the gas support area and further approach the annular flange portion 312.

[0060] Therefore, in order to reduce the direct sliding contact between the tube blank 5 and the fixed surface of the annular flange 312, in this embodiment, a plurality of rotatable support roller groups 33 are arranged circumferentially at intervals along the top of the arc. Each support roller group 33 is located in the same circumferential section of the tube blank channel 311 as the corresponding air outlet 313, so as to provide rolling support for the offset tube blank 5 on the basis of gas support.

[0061] Optionally, each support roller group 33 may include one or more support rollers. Each support roller is rotatably mounted at a corresponding position on the top of the arc via a roller shaft. The roller shaft extends tangentially along the corresponding position of the annular flange 312, so that the rolling direction of the contact part between the support roller and the tube blank 5 is basically consistent with the conveying direction of the tube blank 5. Part of the outer peripheral surface of the support roller protrudes into the tube blank channel 311 and is closer to the axis of the tube blank channel 311 than the fixed surface at the top of the arc, so that when the tube blank 5 deviates significantly to the corresponding circumferential position, it can contact the support roller first.

[0062] When the radial offset of the tube blank 5 has not reached the point where its outer wall contacts the supporting roller, a corresponding gap is maintained between the outer wall of the tube blank 5 and the supporting roller. At this time, the supporting roller group 33 will not participate in continuous bearing (that is, it will not contact the outside of the tube blank 5).

[0063] When the outer wall of the tube blank 5 comes into contact with the support roller at the corresponding circumferential position due to sag or radial displacement, the tube blank 5 drives the support roller to rotate during downstream transport. This changes the continuous sliding friction between the tube blank 5 and the support part to rolling contact. The support roller group 33 not only restricts the tube blank 5 from continuing to approach the support ring 31 to fix the inner wall, but also reduces the relative sliding distance and frictional resistance between the outer wall of the tube blank 5 and the support part, and reduces the dragging effect of contact support on the surface of the soft tube blank 5.

[0064] Based on the above embodiments, further, as Figure 4 As shown, in order to provide installation space for the supporting rollers and their roller shafts at the corresponding position at the top of the arc, a cavity is formed in the tube wall of the supporting tube ring 31 and on the radially outer side of the top of the arc, surrounding the tube blank channel 311. The cavity extends continuously along the circumference of the supporting tube ring 31, and each supporting roller group 33 is respectively embedded and installed in the cavity according to its circumferential position.

[0065] Understandably, the roller body, roller shaft, and mounting base for supporting the roller shaft of the supporting roller assembly 33 are all located in the cavity. The two ends of the roller shaft are respectively supported by the corresponding mounting bases, so that only part of the outer peripheral surface of the supporting roller passes through the cavity and over the top of the arc, and protrudes into the tube blank channel 311, thereby realizing the rotational installation of the supporting roller assembly 33 without significantly occupying the passage space of the tube blank 5.

[0066] Furthermore, to prevent unintended communication between the cavity and the partitioned air chambers 32 or independent air outlet pipes, which could lead to cross-contamination of gases at different circumferential positions and affect the independent detection of pressure changes in each partitioned air chamber 32, the cavity and each partitioned air chamber 32 are separated from each other by the solid cavity wall inside the support ring 31. The independent air outlet pipe can bypass the cavity from one axial side or pass through the cavity area in the form of a closed channel, so that the cavity setting does not affect the mutual isolation between each partitioned air chamber 32 and its air outlet path. Thus, the cavity surrounding the tube blank channel 311 can provide corresponding embedding space for the support roller assemblies 33 at different circumferential positions and keep each support roller in the required protruding position and rotation state.

[0067] It is understandable that when the tube blank 5 deviates significantly and comes into contact with the supporting roller, a small amount of polyethylene residue may adhere to the outer circumference of the supporting roller due to the high temperature of the tube blank 5. At this time, the attached residue may be transferred to the outside of the supporting roller as it comes into contact with the supporting roller and gradually accumulate, thereby affecting the rotation state of the supporting roller and its contact state with the tube blank 5.

[0068] Therefore, as a preferred embodiment of this example, in Figure 4 As shown in the figure, a plurality of scraping members 34 corresponding to the supporting roller assembly 33 are provided inside the cavity, and the scraping part of the scraping member 34 contacts the outer peripheral surface of the corresponding supporting roller located in the cavity.

[0069] At the bottom of the cavity, there is also a discharge port that extends to the outside of the support ring 31.

[0070] For example, each scraper 34 can be fixed to the inner wall of the cavity or to the mounting base of the support roller assembly 33, with its scraping portion extending to and in contact with the outer peripheral surface of the corresponding support roller located in the cavity.

[0071] Furthermore, the scraper 34 can be made of a heat-resistant metal scraper with a certain degree of elasticity or a wear-resistant scraper strip. Its scraping part covers the effective contact width of the supporting roller along the roller axis, and the cutting edge of the scraping part faces the side opposite to the movement direction of the outer peripheral surface of the supporting roller at the contact position. At the same time, the extension direction of the scraping part forms an acute angle with the tangent of the outer peripheral surface of the roller at the contact position, for example, an angle of 30° to 60°. In this way, when the supporting roller rotates with the conveying of the billet 5, the residual material attached to the outer peripheral surface of the roller reaches the scraping part along the movement direction of the outer peripheral surface of the roller, and is separated from the outer peripheral surface of the roller by the blocking effect of the scraping cutting edge, thereby reducing the continuous accumulation of residual material on the surface of the supporting roller and reducing the impact of residual material on the rotation of the supporting roller and subsequent contact support.

[0072] Based on this, as a further preferred embodiment of this example, a brush is also provided at the opening gap formed between the opening through which the supporting roller passes through the top of the arc and the supporting roller, and the bristles of the brush are in contact with the outer peripheral surface of the supporting roller (not shown in the figure), so that the residual material that moves toward the opening gap as the supporting roller rotates is blocked and peeled off by the brush, thereby reducing the situation where residual material adheres and accumulates in the opening gap and affects the rotation state of the supporting roller.

[0073] Accordingly, since the cavity surrounds the billet channel 311 circumferentially along the support ring 31, its bottom refers to the lowest circumferential region located below the billet channel 311 in the normal installation position of the support ring 31, and the discharge port is located in the lowest circumferential region and extends to the outside of the support ring 31; thus, the residual material separated by the scraper 34 can fall along the inside of the cavity to the lowest circumferential region under the action of gravity and collect at the discharge port, so as to clean the residual material in the cavity after the machine stops.

[0074] Alternatively, a sealing cover can be detachably installed at the outer end of the discharge port. The sealing cover keeps the equipment closed during normal operation. After the machine is stopped, the sealing cover is removed, and the suction pipe of the industrial vacuum cleaner is connected to the discharge port. The residual material that cannot be discharged by itself is removed by negative pressure suction. If necessary, a cleaning brush that extends into the discharge port can also be used to clean the adhering residual material.

[0075] In some embodiments, the end of the bearing ring 31 away from the extrusion port 11 is axially spaced from the sizing sleeve 2, and a deflector 35 corresponding to the air outlet 313 is provided circumferentially on the inner wall of the downstream end of the billet channel 311.

[0076] like Figure 6As shown, the deflecting guide 35 includes a connecting plate 351, a straight portion 352, and an inclined portion 353 connected in sequence. The connecting plate 351 is connected to the inner wall of the tube blank channel 311. The straight portion 352 is connected to the connecting plate 351 and extends upstream of the tube blank channel 311. The inclined portion 353 is connected to one end of the straight portion 352 and is inclined towards the inner wall of the tube blank channel 311 gradually in the upstream direction of the tube blank channel 311. The free end of the inclined portion 353 is spaced from the inner wall of the tube blank channel 311.

[0077] A return air zone is formed between the straight portion 352 and the inclined portion 353 and the inner wall of the tube blank channel 311.

[0078] Understandably, in the lateral cross-section formed along the axis of the tube blank channel 311, the connecting plate 351 is generally U-shaped. One end of the plate is connected to the inner wall of the downstream end of the tube blank channel 311, and bends from the inner wall toward the radially inner side of the tube blank channel 311 and then folds back to the upstream direction. The other end of the plate is connected to the straight part 352, thereby making the straight part 352 and the inner wall of the tube blank channel 311 radially spaced apart, and forming the downstream closed end of the return air zone between them.

[0079] Furthermore, to avoid adverse effects of the reversing guide 35 on the extrusion of the tube blank 5, the radial distance between the connecting plates 351 of the oppositely arranged reversing guide 35 is at least greater than the radial distance between the exposed outer peripheral surfaces of the oppositely arranged support rollers. Since the exposed outer peripheral surface of the support roller is the innermost radial limit boundary that the outer wall of the tube blank 5 can reach when it undergoes a large radial offset, and the connecting plate 351 and the straight part 352 and inclined part 353 connected to it are all located radially outside this limit boundary, even if the tube blank 5 offsets to contact the support roller, there is still a clearance between the side of the reversing guide 35 facing the tube blank 5 and the outer wall of the tube blank 5, thereby avoiding interference or dragging effects of the reversing guide 35 on the conveying and extrusion molding of the tube blank 5.

[0080] By setting the deflecting guide 35, part of the supporting gas flowing along the outer wall of the tube blank 5 to the downstream end of the tube blank channel 311 can enter the return air zone through the gap at the free end of the inclined part 353 and be discharged from the circumferential side of the return air zone, so as to reduce the situation where the supporting gas continues to concentrate and flow axially towards the inlet of the sizing sleeve 2. At the same time, the axial gap between the supporting tube ring 31 and the sizing sleeve 2 provides corresponding space for the gas to be discharged outward.

[0081] Specifically, the downstream end of the return air zone is closed by the connecting plate 351, and its upstream end is connected to the tube blank channel 311 through the gap between the free end of the inclined part 353 and the inner wall of the tube blank channel 311, and its side remains open in the circumferential direction; multiple deflecting guides 35 are arranged at intervals along the circumferential direction of the tube blank channel 311, and a circumferential exhaust interval is formed between adjacent deflecting guides 35. The deflecting guides 35 can be segmented guides integrally formed with the support tube ring 31, or they can be heat-resistant guide plates fixedly installed on the inner wall of the tube blank channel 311. The side facing the tube blank 5 remains smooth and maintains a distance from the outer wall of the tube blank 5 within the allowable conveying position range.

[0082] When the supporting gas flows along the outer wall of the tube blank 5 to the downstream end of the tube blank channel 311, some of the gas enters the return air zone through the gap between the free end of the inclined part 353 and the inner wall of the tube blank channel 311, and flows downstream along the return air zone. When the gas reaches the location of the connecting plate 351, its path of continued axial flow is restricted by the connecting plate 351, and then diffuses to the circumferential side of the return air zone, and flows out through the circumferential exhaust gap between the adjacent deflecting guides 35, and then is discharged to the outside through the axial gap between the supporting tube ring 31 and the sizing sleeve 2.

[0083] Furthermore, since the gap at the free end of the inclined section 353, the return air zone, and the circumferential exhaust gap together form an airflow path that has turned and has lateral discharge conditions, when the airflow pressure near the inlet of the sizing sleeve 2 changes briefly, the pressure change needs to pass through the axial gap between the bearing ring 31 and the sizing sleeve 2, the circumferential exhaust gap, the return air zone, and the gap at the free end of the inclined section 353 to be transmitted to the area where the exhaust seam 313 is located. During the transmission process, the airflow changes direction and is discharged outward, which helps to reduce the direct interference of the pressure fluctuation near the inlet of the sizing sleeve 2 on the exhaust state of the exhaust seam 313, so that the air pressure detection results of each partition air chamber 32 can more accurately reflect the change of exhaust gap between the outer wall of the tube blank 5 and the corresponding exhaust seam 313.

[0084] In a further preferred embodiment, a semi-conical guide section 354 may also be provided on the wall surface of the straight portion 352 facing the return air zone. The tip of the semi-conical guide section 354 faces the free end of the inclined portion 353, and its conical surface gradually extends to both circumferential sides of the return air zone along the conveying direction of the tube blank 5. Figure 6 As shown in the diagram, the airflow entering the return air zone from the free end of the inclined portion 353 is directed to both sides for discharge.

[0085] For example, the outline of the semi-conical guide section is equivalent to a half-body structure formed by splitting a cone along a plane containing its axis. The side where the split plane is located is fixed to the wall of the straight section 352 facing the return air zone. The exposed cone surface protrudes into the return air zone, and the axis of the semi-conical guide section can be basically parallel to the axis of the tube blank channel 311. The cone tip is located on the side near the free end of the inclined section 353. The circumferential width of the semi-conical guide section gradually increases along the tube blank 5 conveying direction. The two sides of its cone surface face the two open sides of the return air zone in the circumferential direction. The semi-conical guide section can be integrally formed with the straight section 352, or a heat-resistant guide block fixed to the wall of the straight section 352 can be used. The cone tip can also be rounded to allow the airflow to flow more smoothly along the cone surface to both sides.

[0086] When the supporting gas enters the return air zone through the gap between the free end of the inclined section 353 and the inner wall of the tube blank channel 311, the gas first flows towards the tip of the semi-conical guide section. As it continues to flow downstream, it is guided by the gradually expanding conical surface, deflecting outwards along the conical surface from both sides of the tip. Subsequently, it is discharged through the circumferential sides of the return air zone and the circumferential exhaust gap between adjacent deflector guides 35. Thus, the semi-conical guide section can provide a clear lateral flow path for the gas entering the return air zone, reducing the situation where the gas concentrates its flow towards the connecting plate 351 and experiences local stagnation or disordered backflow at the downstream end of the return air zone. This makes it easier for the gas in the return air zone to leak out to both sides circumferentially and helps to reduce the impact of local pressure fluctuations in the return air zone on the exhaust state of the upstream outlet 313.

[0087] Furthermore, the gas discharged from both sides of the return air zone can diffuse to the adjacent circumferential area of ​​the outer periphery of the tube blank 5 through the circumferential exhaust interval. When this part of the gas passes over the outer surface of the tube blank 5 at the downstream end of the tube blank channel 311, it can form an auxiliary circumferential purging effect, so as to drive the small residues or impurities that are not firmly attached to the outer surface of the tube blank 5 to migrate outward, reducing the situation where the residues or impurities enter the sizing sleeve 2 with the tube blank 5. Therefore, the semi-conical guide section can not only make the gas in the return air zone discharge to both sides along a relatively clear path, but also expand the range of action of the discharged gas in the outer periphery of the tube blank 5.

[0088] In some embodiments, the pipe extruder further includes a frame 4, and the sizing sleeve 2 is mounted on the frame 4 via a displacement adjustment assembly, the displacement adjustment assembly being able to drive the sizing sleeve 2 to move radially;

[0089] The displacement adjustment components are electrically connected to the air pressure detection sensors 322 respectively, and are used to adjust the radial position of the sizing sleeve 2 according to the detection signals of each air pressure detection sensor 322.

[0090] It should be understood that the frame 4 is used to provide an installation base for the sizing sleeve 2 and the displacement adjustment assembly. It can be a profile bracket or a plate support frame fixed on the base of the pipe extrusion production line. The radial movement of the sizing sleeve 2 means that it can be adjusted in a radial plane perpendicular to the conveying direction of the tube blank 5 to change the position of the inlet center of the sizing sleeve 2 relative to the axis of the support tube ring 31. The displacement adjustment assembly can be equipped with a control unit. The signal output terminals of each air pressure detection sensor 322 are electrically connected to the signal input terminal of the control unit, and the control output terminal of the control unit is electrically connected to the radial drive part of the displacement adjustment assembly.

[0091] In the specific production process, the control unit receives the air pressure detection signal corresponding to each partition air chamber 32, and determines the offset orientation of the tube blank 5 in the radial plane based on the relationship that the pressure inside the corresponding partition air chamber 32 increases when the tube blank 5 approaches a certain air outlet 313.

[0092] For example, when the tube blank 5 is within the allowable center range, the reference pressure corresponding to each partition air chamber 32 can be recorded. Then, the real-time detection value of each air pressure detection sensor 322 is compared with the corresponding reference pressure. When the pressure increase at a certain circumferential position exceeds that of its opposite side, it can be determined that the tube blank 5 has shifted to that circumferential position. Based on this, the control unit controls the displacement adjustment component to drive the sizing sleeve 2 to move toward the identified offset direction, so that the inlet center of the sizing sleeve 2 moves closer to the current conveying position of the tube blank 5. The amount of movement of the sizing sleeve 2 can be determined according to the pre-calibrated correspondence between the pressure change and the radial offset of the tube blank 5.

[0093] Furthermore, the displacement adjustment assembly includes a first radial drive member 41 and a second radial drive member 42. The driving directions of the first radial drive member 41 and the second radial drive member 42 are both perpendicular to the axis of the tube blank channel 311, and their driving directions are perpendicular to each other. The first radial drive member 41 is mounted on the frame 4, and the second radial drive member 42 is disposed on the driving part of the first radial drive member 41. The sizing sleeve 2 is connected to the driving part of the second radial drive member 42. That is, the first radial drive member 41 and the second radial drive member 42 are respectively used to drive the sizing sleeve 2 to move in two mutually perpendicular directions in the radial adjustment plane perpendicular to the axis of the tube blank channel 311.

[0094] For example, the first radial drive 41 includes a first radial guide rail fixedly mounted on the frame 4 and a first movable seat that can move along the first radial guide rail. The main body of the second radial drive 42 is fixedly mounted on the first movable seat and includes a second radial guide rail and a second movable seat that can move along the second radial guide rail. The sizing sleeve 2 is fixed to the second movable seat by a mounting seat. The extension directions of the first radial guide rail and the second radial guide rail are both perpendicular to the axis of the billet channel 311 and are perpendicular to each other. When the first radial drive 41 is activated, the first movable seat drives the second radial drive 42 and the sizing sleeve 2 to move together along the first radial guide rail. When the second radial drive 42 is activated, the second movable seat drives the sizing sleeve 2 to move relative to the first movable seat along the second radial guide rail, thereby allowing the displacements in the two radial directions to be superimposed.

[0095] The first radial drive 41 and the second radial drive 42 can be servo electric cylinders, lead screw linear modules or other drive structures that can output controlled linear displacement. The guide part of each radial drive is used to bear the load of the sizing sleeve 2 and the corresponding mounting structure, and to keep the axis of the sizing sleeve 2 basically parallel to the axis of the billet channel 311 during radial movement. When one of the radial drive components is set in the vertical direction, the radial drive component can also be configured with a lead screw transmission structure or braking mechanism with self-locking capability to reduce the positional change of the sizing sleeve 2 due to its own gravity in the state of shutdown or power failure.

[0096] For example, in the normal installation posture where the axis of the tube blank channel 311 extends horizontally, the driving direction of the first radial drive 41 can be set to the horizontal direction perpendicular to the conveying direction of the tube blank 5, and the driving direction of the second radial drive 42 can be set to the vertical direction. The control unit determines the moving direction and amount of the first radial drive 41 based on the pressure difference of the partitioned air chambers 32 on the left and right sides of the tube blank 5, and determines the moving direction and amount of the second radial drive 42 based on the pressure difference of the partitioned air chambers 32 on the upper and lower sides of the tube blank 5. When the tube blank 5 is offset in only one radial direction, the corresponding radial drive is controlled to move. When the tube blank 5 has offset components in two radial directions at the same time, the two radial drives are controlled to move simultaneously or sequentially, so that the sizing sleeve 2 reaches the position in the radial adjustment plane corresponding to the current conveying position of the tube blank 5.

[0097] Thus, the first radial drive member 41 and the second radial drive member 42 essentially form a superimposed two-dimensional linear adjustment structure, which allows the sizing sleeve 2 to change the inlet center position in the radial plane without rotation, and cooperates with the tube blank 5 offset direction identified by each air pressure detection sensor 322, so that the inlet of the sizing sleeve 2 can be adjusted accordingly according to the actual conveying position of the tube blank 5, thereby reducing the situation of local contact or uneven pressure between the tube blank 5 and the inlet of the sizing sleeve 2 when it is offset.

[0098] Example 2:

[0099] Based on Embodiment 1, this embodiment further improves the structure of the scraping component 34. Specifically, the scraping component 34 includes a fixing part 341, an elastic connecting part 342, and a scraping part 343 connected in sequence. The fixing part 341 is installed on the inner wall of the cavity or the mounting seat of the supporting roller assembly 33. Under the pre-pressure of the elastic connecting part 342, the scraping part 343 keeps in contact with the outer peripheral surface of the supporting roller located in the cavity. A plurality of triggering protrusions 331 are provided on one end face of the supporting roller located in the cavity. The elastic connecting part 342 or the fixing part 341 is provided with a receiving part 332 extending into the rotation trajectory of the triggering protrusions 331.

[0100] When the supporting roller rotates, several trigger protrusions 331 rotate with the supporting roller and periodically push the receiving part 332. After the trigger protrusions 331 pass the receiving part 332, the elastic connecting part 342 drives the scraping part 343 to spring back to its original position.

[0101] As Figure 7 As shown, Figure 7 Figure (a) shows the state when the receiving portion 332 of the scraper 34 is not in contact with the triggering protrusion 331 of the supporting roller, while Figure 7 Figure (b) shows the state when the receiving part 332 contacts the trigger protrusion 331. For example, the trigger protrusion 331 can be a cylindrical trigger pin, with the axis of each trigger pin being basically parallel to the axis of the supporting roller, and protruding axially from one end face of the supporting roller located in the cavity. The protruding end is rounded or chamfered. Several trigger pins are evenly distributed circumferentially along the same circular rotation trajectory. For example, three are set and are circumferentially spaced about 120° apart. The radius of the rotation trajectory can be 0.5 to 0.8 times the radius of the supporting roller, so that each trigger pin pushes the receiving part once in turn when the supporting roller rotates once. The pushing frequency increases exponentially with the number of trigger pins. The receiving part 332 can be a lever extending from the elastic connecting part 342 toward the end face of the supporting roller. The upper edge of the end of the lever forms a sloping surface that is inclined toward the trigger pin and extends into the rotation trajectory. When the trigger pin sweeps along the rotation trajectory to the sloping surface, it rises along the sloping surface, causing the elastic connecting part 342 to gradually deflect and store energy. After passing the end of the lever, it suddenly disengages from the sloping surface, and the elastic connecting part 342 then drives the scraping part 343 to spring back to its original position. Further, the diameter of the trigger pin can be 6-10 mm, and its axial protrusion height is based on reliably overlapping with the sloping surface in the axial direction, for example, 8-12 mm. The maximum deflection of the elastic connecting part 342 after being pushed, that is, the pushing stroke, can be 1-3 mm, so that the scraping part 343 can obtain the elastic vibration required for the falling while not detaching too much from the outer circumference of the roller, thus affecting the scraping effect.

[0102] Therefore, while maintaining contact with the outer circumferential surface of the supporting roller, the scraping part 343 can generate a small-amplitude periodic elastic displacement with the rotation of the supporting roller, causing the residual material attached to the edge of the scraping part to be vibrated and fall into the cavity, thereby reducing the situation where the residual material continues to accumulate in the scraping part and re-attach to the supporting roller; and this periodic elastic displacement is triggered by the rotation of the supporting roller itself. When the tube blank 5 contacts the supporting roller and drives it to rotate faster, the operating frequency of the scraping part 343 also increases accordingly, so that the vibration action of the scraping part 34 can change with the actual working state of the supporting roller without the need to set up a separate drive mechanism.

[0103] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0104] Furthermore, it should be noted that the accompanying drawings in this specification are intended to schematically illustrate the structural principles and connection relationships of the present invention. To more clearly present the internal minute features and their operational logic, the shapes, sizes, or proportions of some structures may be appropriately exaggerated or distorted in the drawings, and are mainly shown using line drawing. Therefore, the drawings are only used to assist in understanding the technical solutions of the present invention and should not be regarded as a strict limitation on the actual product size proportions or specific appearance shape of the present invention. The actual dimensions and proportional relationships of each component should be based on the actual manufacturing process and application requirements. However, the positional relationships, connection methods, and operational coordination logic between the components shown in the drawings are clear and accurate.

Claims

1. A pipe extruder for producing PE water pipes, comprising an extrusion main unit, wherein a sizing sleeve is provided downstream of the extrusion port of the extrusion main unit, characterized in that, A support transition member is provided between the extrusion port and the sizing sleeve. The support transition member includes a support tube ring. One end of the support tube ring is connected to the extrusion port, and a tube blank channel for the tube blank to pass through is formed inside it. One end of the tube blank channel connected to the extrusion port forms a die-off expansion section. An inwardly protruding annular flange is formed at the downstream end of the die-off expansion section. The annular flange forms an upstream slope, an arc top, and a downstream slope in sequence along the tube blank conveying direction. The downstream slope has multiple air outlet slits. Multiple circumferentially spaced and isolated partitioned air chambers are provided inside the pipe wall of the bearing ring. Each partitioned air chamber has an air inlet throttling device that is connected to an external air source. Each partitioned air chamber is connected to the corresponding air outlet through an independent air outlet pipeline. A pressure detection sensor is also provided in each partitioned air chamber.

2. The pipe extruder for producing PE water pipes as described in claim 1, characterized in that, The vent seam extends in an arc shape along the circumference of the annular flange, and the opening of the vent seam is located on the downstream slope near the top of the arc.

3. The pipe extruder for producing PE water pipes as described in claim 1, characterized in that, The upstream end of the mold expansion section is connected to the extrusion port, and its inner diameter gradually increases from the upstream end to the downstream end.

4. The pipe extruder for producing PE water pipes as described in claim 1, characterized in that, Multiple sets of supporting rollers, corresponding to the positions of the air outlet seams, are provided circumferentially at the top of the arc, with a portion of the outer circumferential surface of each set of supporting rollers protruding into the tube blank channel.

5. A pipe extruder for producing PE water pipes as described in claim 4, characterized in that, A cavity is formed inside the tube wall of the supporting tube ring and radially outside the top of the arc, surrounding the tube blank channel. The supporting roller assembly is embedded in this cavity.

6. The pipe extruder for producing PE water pipes as described in claim 5, characterized in that, The cavity is also provided with a plurality of scraping parts corresponding to the support roller assembly, and the scraping part of the scraping part contacts the outer peripheral surface of the corresponding support roller located in the cavity. At the bottom of the cavity, there is also a discharge port that extends to the outside of the support ring.

7. The pipe extruder for producing PE water pipes as described in claim 1, characterized in that, The end of the bearing ring away from the extrusion port is axially spaced from the sizing sleeve, and a deflector corresponding to the air outlet slit is provided circumferentially on the inner wall of the downstream end of the billet channel. The deflecting guide includes a connecting plate, a straight section, and an inclined section connected in sequence. The connecting plate is connected to the inner wall of the tube blank channel. The straight section is connected to the connecting plate and extends upstream of the tube blank channel. The inclined section is connected to one end of the straight section and is inclined towards the inner wall of the tube blank channel in the upstream direction. The free end of the inclined section is spaced from the inner wall of the tube blank channel. A return air zone is formed between the straight section and the inclined section and the inner wall of the tube blank channel.

8. A pipe extruder for producing PE water pipes as described in claim 7, characterized in that, The straight section has a semi-conical guide section on the wall facing the return air zone. The tip of the semi-conical guide section faces the free end of the inclined section, and its conical surface gradually extends to both sides of the circumferential direction of the return air zone along the tube blank conveying direction, so as to guide the airflow entering the return air zone from the free end of the inclined section to both sides for discharge.

9. A pipe extruder for producing PE water pipes as described in claim 1, characterized in that, It also includes a frame, and the sizing sleeve is mounted on the frame via a displacement adjustment assembly, which can drive the sizing sleeve to move radially; The displacement adjustment components are electrically connected to the air pressure detection sensors respectively, and are used to adjust the radial position of the sizing sleeve according to the detection signals of each air pressure detection sensor.

10. A pipe extruder for producing PE water pipes as described in claim 9, characterized in that, The displacement adjustment assembly includes a first radial drive member and a second radial drive member with driving directions perpendicular to each other. The first radial drive member is mounted on the frame, and the second radial drive member is disposed on the drive part of the first radial drive member. The sizing sleeve is connected to the drive part of the second radial drive member.

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