cpvc large diameter pipe diameter adjustment device

Abstract

The present invention belongs to the technical field of pipe diameter adjustment, and discloses a caliber adjustment device for large-diameter CPVC pipe fittings, including a rotating bracket and a plurality of groups of expansion dies uniformly slidably mounted on the rotating bracket through an adjustable mounting frame, each group of the expansion dies includes two rollers with parallel rolling cut surfaces, and a guide rail 2 is also installed on the side of the rotating bracket facing the pipe fitting; the adjustable mounting frame includes a slider slidably mounted on the guide rail 2 and a cantilever fixed on the slider. The present invention clamps the inner and outer walls of the pipe fitting by two rollers, and the two rollers adjust the length by a limiter 2 connected between the two cantilevers, thereby achieving rolling clamping of pipe diameters of different pipe mouth thicknesses. And the expansion die as a whole can adjust the distance in the radial direction of the pipe fitting along with the adjustable mounting frame, thereby achieving the adjustment of the pipe diameter expansion amplitude. The adaptation and caliber adjustment work of pipe fittings of different calibers can be performed by only adjusting the radial displacement of the adjustable mounting frame along the pipe fitting.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe diameter adjustment, in particular to a CPPVC large-diameter pipe diameter adjustment device. Background Art

[0002] Due to its advantages such as heat resistance, corrosion resistance and low cost, CPVC pipe diameter is widely used in cable and pipeline laying and other fields. And CPVC pipe fittings can change the inner diameter of the pipe fitting mouth according to the needs of the project due to its excellent flexibility and thermoplastic properties, for docking purposes. The current caliber adjustment method for such large-diameter pipe fittings usually adopts mechanical adjustment method or hot die adjustment method. The mechanical adjustment method is to use a roller to directly expand or reduce the diameter without heating. This adjustment method requires precise adjustment of the force of the pipe fitting, and the operation accuracy is required to be high. The heating die adjustment method is to heat the expansion die to soften the pipe mouth, so that it is more convenient to adjust it. Or use boiling water to heat the pipe mouth to soften the texture of the pipe mouth. However, in the above scheme, basically the caliber adjustment of the pipe mouth requires the die head to be customized and needs to be replaced when used. Especially for the caliber adjustment of large-diameter pipe fittings, the diameter expansion amplitude of the device itself cannot be adjusted as the caliber of the pipe fitting changes, or it cannot be adaptively adjusted as the thickness of the pipe wall. The device is not universal enough.

[0003] Therefore, the present application proposes a diameter adjustment device for large-diameter CPVC pipe fittings to overcome the above-mentioned defects. Summary of the invention

[0004] In order to solve the problems raised in the above background technology, the present invention provides a caliber adjustment device for large-caliber cpvc pipe fittings.

[0005] To achieve the above object, the present invention provides the following technical solutions: a caliber adjustment device for large-caliber cpvc pipe fittings, comprising a rotating bracket and a plurality of groups of diameter-expanding dies uniformly slidably mounted on the rotating bracket through an adjustable mounting bracket, each group of the diameter-expanding dies comprising two rollers with parallel rolling cut surfaces, and a second guide rail is also mounted on the side of the rotating bracket facing the pipe fitting;

[0006] The adjustable mounting frame includes a slider slidably mounted on the second guide rail and a cantilever fixed on the slider, and the adjustable mounting frame also includes a guide rod, one end of which is fixedly connected to a mounting block of one of the diameter expansion die heads, and a mounting block of another diameter expansion die head in the same group is slidably connected to the guide rod;

[0007] Two diameter expansion dies in the same group are respectively installed on a cantilever and the two cantilevers are fixedly connected by a second limiting member and the distance between them can be adjusted. The diameter expansion dies are hinged on the cantilever.

[0008] Preferably, the expansion die head and the adjustable mounting frame are respectively provided with three groups, and two adjacent groups of adjustable mounting frames are connected by a telescopic connecting rod and form an equilateral triangle structure with each adjustable mounting frame as a vertex. The telescopic connecting rod is composed of a sleeve and a sleeve rod that are movably sleeved.

[0009] Preferably, the rotating bracket further comprises a guide rail 1 arranged on the back, a rack slidably mounted on the guide rail 1, a gear mounted on the rotating bracket and meshingly connected with the rack, and a transmission member coaxially connected with the gear;

[0010] The rack is fixedly connected to a sliding block of one set of adjustable mounting frames through a connecting piece.

[0011] Preferably, the transmission member is detachably mounted with a torque member, the torque member is composed of an external knob, an internal spring and a rotating shaft drivingly connected thereto, the rotating shaft is spline-connected to the axis of the transmission member;

[0012] At least two types of torsion members are provided, and the elastic torsion directions of the spring torsion springs inside the two types of torsion members are clockwise and counterclockwise respectively.

[0013] Preferably, both ends of the guide rail 1 are equipped with a limiting member 1 for limiting the maximum displacement distance of the rack on the guide rail 1.

[0014] Preferably, the rotating bracket further comprises a damping rod arranged thereon, the telescopic end of the damping rod is connected to the rack, and the extension direction of the telescopic end of the damping rod is consistent with the displacement direction of the rack.

[0015] Preferably, the aperture adjustment device further comprises a driving frame and an angle adjustment structure, wherein the driving frame comprises a mounting seat and a spindle mounted on the mounting seat, and further comprises a fixed sleeve and a movable sleeve, wherein the fixed sleeve is fixed to the mounting seat and thus relatively fixed in position on the spindle, and the movable sleeve is slidably sleeved on the spindle;

[0016] The angle adjustment mechanism comprises a connecting rod 1 and a connecting rod 2, the two ends of the connecting rod 2 are respectively hinged to the diameter expansion die head and the connecting rod 1, the middle part of the connecting rod 2 is hinged to the slider, and the bottom end of the connecting rod 1 is hinged to the moving sleeve.

[0017] Preferably, the fixed sleeve and the movable sleeve are connected by an electric telescopic rod and the distance between them can be adjusted.

[0018] Preferably, the caliber adjustment device also includes a fixed frame, a power supply slip ring is arranged on the fixed frame, the fixed frame is fixedly connected to the mounting seat and does not rotate with the main shaft, a brush is arranged on the rotating bracket and is slidably connected to the power supply slip ring, a heater is installed on the expansion die head, and the heater is electrically connected to the brush, and the heater is provided with heating wires on both sides of the pipe.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides two rollers in each group of expansion die heads, the two rollers are clamped on the inner and outer walls of the pipe fitting, and the lengths of the two rollers are adjusted by a stopper connected between two cantilevers, thereby achieving rolling clamping of pipe diameters with different pipe opening thicknesses, thereby improving its applicability. The adjustment method is simple and stable. The expansion die head as a whole can adjust the distance in the radial direction of the pipe fitting along with the adjustable mounting frame, thereby achieving the adjustment of the pipe diameter expansion amplitude. Only by adjusting the radial displacement of the adjustable mounting frame along the pipe fitting, the adaptation and caliber adjustment of pipe fittings with different calibers can be performed.

[0021] The spring in the torsion piece is applied with elastic potential energy by twisting the knob on it in advance, and then its rotating shaft is docked with the axis of the transmission part, so that it can drive the axis of the transmission part to rotate, so that the rack moves along the guide rail. That is, the expansion die head can move along the radial direction of the pipe mouth, and the expansion die head can achieve the effect of reducing and expanding the diameter. In addition, a damping rod is set to maintain a uniform displacement rate, control the force balance, and avoid damage to the pipe fittings caused by uneven caliber adjustment pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention;

[0023] Figure 2 It is a perspective structural schematic diagram of the present invention;

[0024] Figure 3 It is a back view of the rotating bracket of the present invention;

[0025] Figure 4 It is a front view of the rotating bracket of the present invention;

[0026] Figure 5 It is a schematic diagram of the layout of the rotating support, the diameter expansion die, the heater and the triangular connection mechanism of the present invention;

[0027] Figure 6 It is a schematic diagram of the transmission structure on the rotating bracket of the present invention;

[0028] Figure 7 A schematic diagram of an embodiment of the present invention in which a damping rod is added.

[0029] In the figure: 100, rotating bracket; 101, torque member; 102, rack; 103, gear; 104, guide rail one; 1041, limit member one; 105, transmission member; 106, guide rail two; 107, damping rod; 200, expansion die; 201, mounting block; 300, adjustable mounting frame; 301, slider; 302, cantilever; 303, guide rod; 304, limit member two; 400, fixed frame; 401, power supply slip ring; 500, heater; 600, telescopic connecting rod; 701, connecting rod one; 702, connecting rod two; 801, mounting seat; 802, main shaft; 803, fixed sleeve; 804, movable sleeve; 805, electric telescopic rod. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] like Figures 1 to 7 As shown, the present invention provides a caliber adjustment device for large-caliber cpvc pipe fittings, comprising a rotating bracket 100 and a plurality of groups of diameter-expanding dies 200 uniformly slidably mounted on the rotating bracket 100 through an adjustable mounting bracket 300, each group of diameter-expanding dies 200 comprises two rollers with rolling cut surfaces arranged in parallel, and a guide rail 2 106 is also mounted on the side of the rotating bracket 100 facing the pipe fitting;

[0032] The adjustable mounting frame 300 includes a slider 301 slidably mounted on the guide rail 106 and a cantilever 302 fixedly mounted on the slider 301. The adjustable mounting frame 300 also includes a guide rod 303, one end of which is fixedly connected to the mounting block 201 of one of the diameter expansion die heads 200, and the mounting block 201 of another diameter expansion die head 200 in the same group is slidably connected to the guide rod 303;

[0033] The two diameter expansion dies 200 of the same group are respectively installed on a cantilever 302 , and the two cantilevers 302 are fixedly connected by a second limiting member 304 and the distance between them can be adjusted. The diameter expansion die 200 is hinged on the cantilever 302 .

[0034] Each set of expansion die heads 200 is respectively provided with two rollers, which are located on the inner and outer sides of the pipe fitting in a clamping posture, and the two rollers are adjusted in length by a limiter 2 304 connected between the two cantilevers 302. The limiter 2 304 is composed of a stud and a nut, and is used to adjust the distance between the two cantilevers 302, that is, the parallel distance of the cross-sections between the rollers. In this way, the rolling clamping of pipe diameters with different pipe mouth thicknesses is achieved, thereby improving its applicability. And the adjustment method is simple and stable. The extension direction of the guide rail 2 106 is the radial direction of the pipe fitting, perpendicular to the central axis of the pipe fitting. The expansion die head 200 as a whole can adjust the distance in the radial direction of the pipe fitting along with the adjustable mounting frame 300, thereby achieving the adjustment of the expansion amplitude of the pipe diameter.

[0035] like Figure 3 As shown, three groups of expansion die heads 200 and adjustable mounting frames 300 are provided correspondingly, and two adjacent groups of adjustable mounting frames 300 are connected by telescopic connecting rods 600 and form an equilateral triangle structure with each adjustable mounting frame 300 as a vertex. The telescopic connecting rod 600 is composed of a sleeve and a sleeve rod that are movably sleeved.

[0036] The two ends of the telescopic connecting rod 600 are fixedly connected to the adjustable mounting frame 300 to keep the angles of the equilateral triangle unchanged. The main purpose of this arrangement is that when one set of adjustable mounting frames 300 moves along the guide rail 2 106, the other two sets can move synchronously with the displacement of one of the vertices of the equilateral triangle structure. Therefore, when expanding the pipe diameter, only one of the adjustable mounting frames 300 needs to be adjusted to slide along the pipe diameter direction to synchronously adjust the remaining adjustable mounting frames 300, eliminating the process of adjusting each adjustable mounting frame 300 separately, avoiding the error caused by separate adjustment, improving the accuracy and reducing the difficulty of adjustment.

[0037] like Figure 1-Figure 3 As shown, the rotating bracket 100 further includes a guide rail 104 disposed on the back, a rack 102 slidably mounted on the guide rail 104, a gear 103 mounted on the rotating bracket 100 and meshingly connected to the rack 102, and a transmission member 105 coaxially connected to the gear 103;

[0038] The rack 102 is fixedly connected to the slider 301 of one set of adjustable mounting brackets 300 via a connecting piece.

[0039] The guide rail 104 points in the radial direction of the pipe, and the rack 102 slides linearly on the guide rail 104, and the rack 102 is connected to the adjustable mounting frame 300 through a connecting piece, so that the adjustable mounting frame 300 is driven to move synchronously along the radial direction of the pipe during the sliding process of the rack 102, so that the diameter expansion die 200 expands the pipe diameter. The rack 102 only needs to be connected to one set of adjustable mounting frames 300, and the other sets of adjustable mounting frames 300 can be synchronously moved through the equilateral triangle configuration formed by the telescopic connecting rod 600.

[0040] like Figure 6 As shown, the transmission member 105 is detachably mounted with a torque member 101, which is composed of an external knob, an internal spring and a rotating shaft connected to the external knob, and the rotating shaft is spline-connected to the axis of the transmission member 105;

[0041] At least two types of torsion members 101 are provided, and the elastic torsion directions of the spring torsion springs inside the two types of torsion members 101 are clockwise and counterclockwise, respectively.

[0042] The transmission member 105 is used to transmit between the torque member 101 and the gear 103. The spring in the torque member 101 is applied with elastic potential energy by twisting the knob thereon in advance, and then the rotating shaft thereof is docked with the axis of the transmission member 105, so that the axis of the transmission member 105 can be driven to rotate, so that the rack 102 moves along the guide rail 104. That is, the expansion die 200 can move along the radial direction of the pipe orifice, and the expansion die 200 can further achieve the effect of reducing and expanding the diameter.

[0043] The torque member 101 includes at least two types, the difference being that the torsion springs have different torsion directions, so that after accumulating force, they can drive the transmission member 105 to rotate clockwise or counterclockwise, thereby driving the rack 102 to move in different directions.

[0044] like Figure 6 As shown, both ends of the guide rail 104 are installed with limit members 1041 for limiting the maximum displacement distance of the rack 102 on the guide rail 104 .

[0045] The limitation on the maximum displacement distance is the limitation on the expansion range of the pipe orifice. When the pipe expansion reaches the design requirement, the displacement of the rack 102 will be blocked by the limiter 1041, causing the displacement to finally stop and the expansion work is completed.

[0046] like Figure 7 As shown, the rotating bracket 100 also includes a damping rod 107 disposed thereon, the telescopic end of the damping rod 107 is connected to the rack 102 , and the extension direction of the telescopic end of the damping rod 107 is consistent with the displacement direction of the rack 102 .

[0047] The damping rod 107 is used to provide damping for the linear motion of the rack 102 and to control the travel speed of the rack 102 to avoid it from traveling too fast and to control the travel speed evenly, so that the expansion die 200 opens slowly and expands the pipe orifice at a uniform speed.

[0048] The damping rod 107 has damping when it is extended or retracted, so it can be set in the form of setting smaller air inlets connected to the external environment in the inner cavities on both sides of the piston to control the speed of air flow and thus achieve control of the extension and retraction speed.

[0049] like Figure 1 and Figure 2 As shown, the aperture adjustment device further includes a driving frame and an angle adjustment structure. The driving frame includes a mounting seat 801 and a spindle 802 mounted on the mounting seat 801, and further includes a fixed sleeve 803 and a movable sleeve 804. The fixed sleeve 803 is fixed to the mounting seat 801 and thus has a relatively fixed position on the spindle 802, while the movable sleeve 804 is slidably sleeved on the spindle 802.

[0050] The angle adjustment mechanism includes connecting rod 1 701 and connecting rod 2 702 . The two ends of connecting rod 2 702 are respectively hinged to the expansion die 200 and connecting rod 1 701 . The middle part of connecting rod 2 702 is hinged to the slider 301 . The bottom end of connecting rod 1 701 is hinged to the moving sleeve 804 .

[0051] The movable sleeve 804 is controlled to move forward and backward along the linear direction of the main shaft 802, so that the top end of the connecting rod 1 701 drives the connecting rod 2 702 to rotate, and the rotation angle of the diameter expansion die 200 is adjusted. The angle adjustment process can be carried out synchronously during the rotation of the diameter expansion die 200 around the pipe fitting. Through the angle adjustment of the diameter expansion die 200, the pipe opening of the pipe fitting can be expanded into an open trumpet shape to meet different diameter expansion requirements.

[0052] The main shaft 802 is connected to a driving device for providing a power source for rotation.

[0053] like Figure 1 and Figure 2 As shown, the fixed sleeve 803 and the movable sleeve 804 are connected by an electric telescopic rod 805 and the distance between them can be adjusted.

[0054] The movable sleeve 804 is driven to move forward and backward by the electric telescopic rod 805 , and the top of the connecting rod 1 701 is pushed upward to cause one end of the connecting rod 2 702 to tilt up or sink and rotate around the hinge axis with the slider 301 .

[0055] like Figure 1 and Figure 2As shown, the caliber adjustment device also includes a fixed frame 400, on which a power supply slip ring 401 is arranged, the fixed frame 400 is fixedly connected to the mounting seat 801 and does not rotate with the main shaft 802, a brush is arranged on the rotating bracket 100 and is slidably connected to the power supply slip ring 401, a heater 500 is installed on the expansion die 200, and the heater 500 is electrically connected to the brush, and the heater 500 is provided with heating wires on both sides of the pipe fitting.

[0056] The above scheme can provide a heating device for pipe fittings. In order to make the pipe fittings heated evenly, a heater 500 that can follow the pipe fittings to revolve is selected on the expansion die 200. The heater 500 is provided with electric heating wires on both the inner and outer sides of the pipe fittings, which can heat the pipe fittings to about 95 degrees Celsius, reaching a temperature that can cause the cpvc pipe fittings to deform. And the ambient temperature can be maintained between these two by faster rotation. The fixed frame 400 and the power supply slip ring 401 arranged thereon and the brush on the rotating bracket 100 are responsible for providing current to it during its rotation. This device chooses to directly heat the pipe mouth by thermal radiation to make it vitrified. Compared with the traditional die head heating method, the heat conduction efficiency is higher, and the problems of melting of the pipe mouth and low heat conduction efficiency caused by direct heating of the die head are avoided. Compared with the mechanical expansion method, the requirements for operation accuracy are reduced and the fault tolerance rate is improved.

[0057] The working principle and use process of the present invention:

[0058] The two rollers on the expansion die 200 are clamped on the inner and outer sides of the pipe mouth, and the clamping amplitude is adjusted by the second limiter 304. The extension direction of the guide rail 106 is the radial direction of the pipe fitting, which is perpendicular to the central axis of the pipe fitting. The spring in the torsion piece 101 is applied with elastic potential energy by twisting the knob thereon in advance, and then its rotating shaft is docked with the axis of the transmission piece 105, so that it can drive the axis of the transmission piece 105 to rotate, so that the rack 102 moves along the guide rail 104. That is, the expansion die 200 can move along the radial direction of the pipe mouth, and the expansion die 200 can achieve the effect of reducing and expanding the diameter.

[0059] The expansion die 200 is provided with a heater 500 that can follow the tube to revolve. The heater 500 is provided with heating wires on both the inner and outer sides of the tube to reach a temperature that can cause the cpvc tube to deform. And the ambient temperature can be maintained within this range through faster rotation. The fixed frame 400 and the power supply slip ring 401 provided thereon and the brushes on the rotating bracket 100 are responsible for providing current to the rotating bracket during its rotation.

[0060] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. The caliber adjustment device for cpvc large-caliber pipe fittings is characterized by: It comprises a rotating bracket (100) and a plurality of groups of expansion dies (200) uniformly slidably mounted on the rotating bracket (100) via an adjustable mounting bracket (300), each group of the expansion dies (200) comprising two rollers with rolling cut surfaces arranged in parallel, and a second guide rail (106) is also mounted on the side of the rotating bracket (100) facing the pipe fitting; The adjustable mounting frame (300) comprises a slider (301) slidably mounted on the second guide rail (106) and a cantilever (302) fixedly mounted on the slider (301). The adjustable mounting frame (300) further comprises a guide rod (303), one end of the guide rod (303) being fixedly connected to a mounting block (201) of one of the diameter expansion dies (200), and the mounting block (201) of another diameter expansion dies (200) in the same group is slidably connected to the guide rod (303); Two diameter expansion dies (200) of the same group are respectively installed on a cantilever (302), and the two cantilevers (302) are fixedly connected via a second limiting member (304) and the distance between them can be adjusted, and the diameter expansion die (200) is hinged on the cantilever (302); The diameter expansion die head (200) and the adjustable mounting frame (300) are respectively provided in three groups, and two adjacent groups of adjustable mounting frames (300) are connected by a telescopic connecting rod (600) and form an equilateral triangle structure with each adjustable mounting frame (300) as a vertex, and the telescopic connecting rod (600) is formed by a sleeve and a sleeve rod that are movably sleeved; The rotating bracket (100) further comprises a guide rail (104) arranged on the back side, a rack (102) slidably mounted on the guide rail (104), a gear (103) mounted on the rotating bracket (100) and meshingly connected to the rack (102), and a transmission member (105) coaxially connected to the gear (103); the rack (102) is fixedly connected to a slider (301) of one set of adjustable mounting brackets (300) via a connecting member; The transmission member (105) is detachably mounted with a torque member (101), wherein the torque member (101) is composed of an external knob, an internal spring and a rotating shaft connected to the rotating shaft, wherein the rotating shaft is spline-connected to the axis of the transmission member (105); At least two types of torsion members (101) are provided, and the elastic torsion directions of the springs inside the two types of torsion members (101) are clockwise and counterclockwise, respectively.

2. The caliber adjustment device for large-caliber cpvc pipe fittings according to claim 1 is characterized in that: Limiting members 1 (1041) are installed at both ends of the guide rail 1 (104) for limiting the maximum displacement distance of the rack (102) on the guide rail 1 (104).

3. The caliber adjustment device for large-caliber cpvc pipe fittings according to claim 2 is characterized in that: The rotating bracket (100) further comprises a damping rod (107) arranged thereon, the telescopic end of the damping rod (107) being connected to the rack (102), and the extension direction of the telescopic end of the damping rod (107) being consistent with the displacement direction of the rack (102).

4. The caliber adjustment device for large-caliber cpvc pipe fittings according to any one of claims 1 to 3, characterized in that: The caliber adjustment device further comprises a drive frame and an angle adjustment structure, wherein the drive frame comprises a mounting seat (801) and a main shaft (802) mounted on the mounting seat (801), and further comprises a fixed sleeve (803) and a movable sleeve (804), wherein the fixed sleeve (803) is fixed to the mounting seat (801) and thus relatively fixed in position on the main shaft (802), and the movable sleeve (804) is slidably sleeved on the main shaft (802); The angle adjustment structure comprises a connecting rod 1 (701) and a connecting rod 2 (702), wherein the two ends of the connecting rod 2 (702) are respectively hinged to the diameter expansion die (200) and the connecting rod 1 (701), the middle part of the connecting rod 2 (702) is hinged to the slider (301), and the bottom end of the connecting rod 1 (701) is hinged to the moving sleeve (804).

5. The caliber adjustment device for large-caliber cpvc pipe fittings according to claim 4 is characterized in that: The fixed sleeve (803) and the movable sleeve (804) are connected via an electric telescopic rod (805) and the spacing between them can be adjusted.

6. The caliber adjustment device for large-caliber cpvc pipe fittings according to claim 4 is characterized in that: The caliber adjustment device also includes a fixed frame (400), a power supply slip ring (401) is arranged on the fixed frame (400), the fixed frame (400) is fixedly connected to the mounting seat (801) and does not rotate with the main shaft (802), a brush is arranged on the rotating bracket (100) and is slidably connected to the power supply slip ring (401), a heater (500) is installed on the diameter expansion die (200), and the heater (500) is electrically connected to the brush, and the heater (500) is provided with heating wires on both sides of the pipe.

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