A pipe expansion device for shrinkable PE pipes

Abstract

The application relates to the field of pipeline processing, and discloses a pipe expanding device for a shrinkable PE pipeline, which comprises a rack and a mounting plate, an oil cylinder is internally mounted in the rack, a metal conical die is mounted at the telescopic end of the oil cylinder, and a clamping mechanism is further arranged, which comprises a plurality of groups of clamping plates I fixedly mounted on the right side of the mounting plate and a plurality of groups of supporting columns, a fixing ring is fixedly connected to the right end of the supporting column, a plurality of groups of connecting columns are movably sleeved on the inner wall of the fixing ring, and a clamping plate II is fixedly mounted at one end of the connecting column. The device is limited by the limit frame and the positioning groove formed in the inner wall of the limit frame, when the cylinder drives the limit frame to horizontally move through the connecting ring, the connecting column and the clamping plate II are driven to move back and forth along the diameter of the fixing ring in cooperation with the fixing ring, so that the synchronous clamping and telescopic operation of the plurality of groups of clamping plates II are realized, and the fixing effect of the device is remarkably improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of pipeline processing, in particular to an expanding device for a shrinkable PE pipeline. BACKGROUND

[0002] The PE pipeline is a plastic pipeline piece made of high molecular materials, which is generally placed in a circulating softening pool for softening, the PE pipeline is soaked by circulating liquid, and the circulating liquid is a multi-component refrigerant oil cooling liquid (a composite liquid composed of various oils, additives and water), then the softened pipeline is sleeved on a metal conical die, and the metal conical die is pushed by an oil cylinder to expand the pipeline under the fixation of the peripheral clamping part; the prior art adopts multiple (not less than eight) cylinders to drive clamping blocks to clamp the outer side of the pipeline, and the clamping action is completed in cooperation with the sleeving support of the metal conical die on the inner side of the pipeline, but the cylinders are easy to have different pushing strokes, which leads to different clamping of the pipeline surface and poor clamping effect, that is, the part for rigidly clamping the periphery of the pipeline cannot realize high-precision synchronous extension and retraction, so that the softened PE pipeline is unevenly stressed, and the final expanding effect is seriously affected, therefore, the application is dedicated to redesigning the outer clamping system to realize high synchronization when clamping the PE pipeline. SUMMARY

[0003] The application provides an expanding device for a shrinkable PE pipeline, which has the advantages of protecting the pipeline and fixing the high efficiency, and solves the problem of poor synchronous extension and retraction of multiple clamping cylinders in the prior art.

[0004] To achieve the above-mentioned purpose, the application adopts the following technical scheme: an expanding device for a shrinkable PE pipeline, comprising a rack and a mounting plate, an oil cylinder is installed in the inside of the rack, a metal conical die is installed at the extension end of the oil cylinder, and the device further comprises:

[0005] A clamping mechanism, which comprises a plurality of clamping plates one fixedly installed on the right side of the mounting plate and a plurality of support columns, a fixed ring is fixedly connected to the right end of the support column, a plurality of connecting columns are movably sleeved on the inner wall of the fixed ring, a clamping plate two is fixedly installed at one end of the connecting column, a fixed block is fixedly installed at the other end of the connecting column, a limiting wheel is rotatably installed in the inside of the fixed block, a plurality of cylinders are fixedly installed on the right side of the mounting plate, a connecting ring is fixedly connected to the extension end of the cylinder, a limiting frame is fixedly installed on the right side of the connecting ring, positioning grooves are formed in the front and back sides of the inner wall of the limiting frame, and the limiting wheel is slidingly installed in the positioning groove.

[0006] The cooling mechanism includes a mounting frame installed on the top of the rack and a liquid collecting tank located on the right side of the rack. A circulating heating pool is placed behind the liquid collecting tank. A drainage trough is fixedly installed on the bottom of the mounting frame. A liquid inlet pipe is fixedly connected to the top of the drainage trough. The cooling mechanism sprays circulating liquid downward.

[0007] Preferably, a rectangular drain outlet is provided at the bottom of the drainage trough, a guide plate is fixedly connected to the top of the inner wall of the drainage trough, and diversion strips are horizontally and equidistantly provided on the front and rear sides of the inner wall of the drainage trough.

[0008] Preferably, both the front and rear sides of the bottom of the rectangular drain outlet are fixedly connected with a sealer, and the distance between the two groups of sealers is smaller than the width of the rectangular drain outlet.

[0009] Preferably, a communicating pipe and a pump are installed between the liquid collecting tank and the circulating heating pool, and the communicating pipe and the pump are used to transport the circulating liquid in the liquid collecting tank to the circulating heating pool.

[0010] Preferably, the clamping plate 1 is located on the left side of the clamping plate 2, and the number of the clamping plate 1 and the clamping plate 2 are both eight groups, and they are all equidistantly distributed around the outer surface of the metal conical mold. Multiple groups of the clamping plate 1 and multiple groups of the clamping plate 2 respectively form two groups of circular structures, one large and one small.

[0011] Preferably, the axes of the connecting columns are perpendicular to the axial direction of the metal conical mold, and the number of the connecting columns is eight groups, which are equidistantly distributed around the outer surface of the metal conical mold.

[0012] Preferably, the number of the cylinders is four groups, and they are equidistantly distributed around the outer surface of the metal conical mold, and the connecting ring is located between the clamping plate 1 and the fixing ring.

[0013] Preferably, the connecting ring is an annular structure, and the supporting column is adapted to pass through the surface of the connecting ring.

[0014] Preferably, the limiting frame is distributed obliquely as a whole, and an angle of 30° is formed between the long side of the limiting frame and the axis of the metal conical mold.

[0015] Preferably, the longitudinal cross-section of the guide plate is in the shape of a "human", and rectangular protrusions are provided on the front and rear sides of the guide plate.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. This device has been redesigned to achieve the synchronous extension and retraction and clamping functions of multiple groups of connecting columns and clamping plate 2, which is beneficial to protecting the workpiece and making it uniformly clamped. By providing a fixed ring and fixing it horizontally on the right side of the mounting plate through a liquid collecting box, multiple groups of connecting columns used to clamp the pipes can be evenly adapted to the inner wall of the fixed ring. A limiting wheel is provided for rotation at one end of the fixed ring, and the limiting is performed by an inclined limit frame and a positioning groove provided on the inner wall of the limit frame. When the cylinder drives the limit frame to move horizontally through the connecting ring, it just cooperates with the fixed ring to drive the connecting column and the clamping plate 2 to move back and forth along the radial line of the fixed ring, thereby realizing the synchronous clamping and extension operation of multiple groups of clamping plates 2, thereby significantly improving the fixing effect of the device.

[0018] 2. The device also redesigns the cooling mechanism so that the circulating fluid used to cool and shape the pipeline can flow more evenly and be distributed on the pipeline surface. Compared with the traditional multi-group pipeline uniform water spraying, the device is designed with a drainage trough so that the rectangular drain port at the bottom can make the circulating fluid flow downward in a linear distribution to the workpiece surface. By installing a "human" shaped guide plate on the top of the inner wall of the drainage trough, the circulating fluid entering the inner cavity of the drainage trough is evenly distributed throughout the inner cavity of the drainage trough. When the circulating fluid passes over the guide plate and begins to flow on the front and back sides of the inner wall of the drainage trough, the circulating fluid is further diverted by the multi-component diversion strips distributed on the inner wall of the drainage trough, so that the circulating fluid passing through the inner wall of the sealer can flow downward evenly, so that the circulating fluid can be more evenly distributed on the workpiece surface when it falls, thereby improving the cooling efficiency of the device.

[0019] 3. Finally, this device utilizes multiple fixed sets of clamping plates one to clamp the workpiece after expansion, and cooperates with the adjustable clamping plate two to complete the all-round clamping operation of the workpiece. When the oil cylinder drives the metal cone die to move to the right, it can be reset by moving the cylinder to the left, driving the connecting ring and the limit frame to move to the left, and limiting the limit wheel with the positioning groove, so that the limit wheel drives the fixed block, the connecting column and the clamping plate two to move synchronously toward the side away from the axis of the metal cone die. At this time, the multiple sets of clamping plates two form a clamping area with a larger diameter, thereby cooperating with the clamping plate one to achieve a more reliable clamping and fixing function for the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute a part of the specification, illustrate embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application in a clear and understandable manner.

[0021] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

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

[0023] Figure 2 It is a front cutaway schematic diagram of the overall structure of the present invention;

[0024] Figure 3 For the present invention Figure 2 A magnified schematic diagram of the structure at A in the middle;

[0025] Figure 4 A side cross-sectional schematic diagram of the mounting frame and the drain trough of the present invention;

[0026] Figure 5 is a three-dimensional schematic diagram of the clamping structure of the present invention;

[0027] Figure 6 A schematic diagram of the separation of the clamping structure of the present invention;

[0028] Figure 7 It is a side cutaway schematic diagram of the clamping structure of the present invention;

[0029] Figure 8 For the present invention Figure 7 A magnified schematic diagram of the structure at B in the middle;

[0030] Figure 9 It is a side view schematic diagram of the overall structure of the present invention;

[0031] Figure 10 It is a schematic diagram of the internal cross section of the drainage tank of the present invention;

[0032] Figure 11 Schematic diagram of the internal structure of the limit frame of the present invention.

[0033] Among them: 1. Frame; 2. Mounting plate; 3. Cylinder; 4. Metal conical mold; 5. Mounting frame; 6. Drain trough; 7. Filter; 8. Liquid inlet pipe; 9. Guide plate; 10. Diverter strip; 11. Liquid collecting box; 12. Circulating heating pool; 13. Clamping plate 1; 14. Support column; 15. Fixed ring; 16. Cylinder; 17. Connecting ring; 18. Limiting frame; 19. Positioning groove; 20. Connecting column; 21. Clamping plate 2; 22. Fixed block; 23. Limiting wheel. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] See also Figures 1-11This embodiment discloses a pipe expansion device for a shrinkable PE pipe, comprising a frame 1 and a mounting plate 2. A cylinder 3 is mounted inside the frame 1, and a metal conical die 4 is mounted at the telescopic end of the cylinder 3. The device also includes:

[0036] The clamping mechanism includes multiple groups of clamping plates 13 and multiple groups of support columns 14 fixedly mounted on the right side of the mounting plate 2. The right end of the support column 14 is fixedly connected to a fixing ring 15. The inner wall of the fixing ring 15 is movably sleeved with multiple groups of connecting columns 20. One end of the connecting column 20 is fixedly mounted with a clamping plate 21. The other end of the connecting column 20 is fixedly mounted with a fixing block 22. The internal rotation of the fixing block 22 is installed with a limiting wheel 23. The right side of the mounting plate 2 is fixedly mounted with multiple groups of cylinders 16. The telescopic end of the cylinder 16 is fixedly connected to a connecting ring 17. The right side of the connecting ring 17 is fixedly mounted with a limiting frame 18. The front and rear sides of the inner wall of the limiting frame 18 are provided with positioning grooves 19. The limiting wheel 23 is slidably installed in the positioning groove 19.

[0037] The cooling mechanism includes a mounting frame 5 mounted on the top of the frame 1 and a liquid collecting tank 11 located on the right side of the frame 1. A circulating heating pool 12 is placed behind the liquid collecting tank 11. A drainage trough 6 is fixedly mounted on the bottom of the mounting frame 5. A liquid inlet pipe 8 is fixedly connected to the top of the drainage trough 6. The cooling mechanism sprays circulating liquid downward.

[0038] The device has been redesigned to achieve synchronous extension and clamping of multiple groups of connecting columns 20 and clamping plates 21, which is beneficial to protecting the workpiece so that it is evenly clamped. By providing a fixing ring 15 and fixing it horizontally on the right side of the mounting plate 2 through the collecting box 11, multiple groups of connecting columns 20 used to clamp the pipes can be evenly adapted to the inner wall of the fixing ring 15. A limiting wheel 23 is rotatably provided at one end of the fixing ring 15, and is limited by an inclined limiting frame 18 and a positioning groove 19 provided on the inner wall of the limiting frame 18. When the cylinder 16 drives the limiting frame 18 to move horizontally through the connecting ring 17, it just cooperates with the fixing ring 15 to drive the connecting columns 20 and the clamping plate 21 to move back and forth along the radial line of the fixing ring 15, thereby realizing synchronous clamping and extension operations of multiple groups of clamping plates 21, thereby significantly improving the fixing effect of the device.

[0039] This device utilizes multiple fixed sets of clamping plates 13 to clamp the workpiece after expansion, and cooperates with the adjustable clamping plate 21 to complete the all-round clamping operation of the workpiece. When the cylinder 3 drives the metal conical mold 4 to move to the right, it can be reset by the cylinder 16 to the left, driving the connecting ring 17 and the limit frame 18 to move to the left, and the positioning groove 19 to limit the limit wheel 23, so that the limit wheel 23 drives the fixed block 22, the connecting column 20 and the clamping plate 21 to move synchronously toward the side away from the axis of the metal conical mold 4. At this time, the multiple sets of clamping plates 21 form a clamping area with a larger diameter, thereby cooperating with the clamping plate 13 to achieve a more reliable clamping and fixing function for the workpiece.

[0040] The bottom of the drainage trough 6 is provided with a rectangular drain port, the top of the inner wall of the drainage trough 6 is fixedly connected with a guide plate 9, and the front and rear sides of the inner wall of the drainage trough 6 are both horizontally and equidistantly provided with diverter strips 10;

[0041] The present device has also redesigned the cooling mechanism so that the circulating fluid used to cool and shape the pipeline can flow more evenly and be distributed on the pipeline surface. Compared with the traditional multi-group pipeline uniform water spraying, the present device is designed with a drainage trough 6 so that the rectangular drain outlet at its bottom can flow the circulating fluid downward in a linear distribution to the workpiece surface. By installing a "human" shaped guide plate 9 on the top of the inner wall of the drainage trough 6, the circulating fluid entering the inner cavity of the drainage trough 6 is evenly distributed throughout the inner cavity of the drainage trough 6. When the circulating fluid passes over the guide plate 9 and begins to flow on the front and back sides of the inner wall of the drainage trough 6, the circulating fluid is further diverted by the multi-component flow strips 10 distributed on the inner wall of the drainage trough 6, so that the circulating fluid passing through the inner wall of the mouthpiece 7 can flow evenly downward, thereby improving the cooling efficiency of the device.

[0042] Among them, the front and rear sides of the bottom of the rectangular drain outlet are fixedly connected with a sealer 7, and the distance between the two groups of sealers 7 is smaller than the width of the rectangular drain outlet;

[0043] A drainage channel smaller in size than the rectangular drainage port is formed between the two groups of closing devices 7, which can increase the flow rate of the circulating liquid and improve the discharge efficiency of the circulating liquid.

[0044] A connecting pipe and a pump are installed between the liquid collecting tank 11 and the circulating heating pool 12, and the connecting pipe and the pump are used to transport the circulating liquid in the liquid collecting tank 11 to the circulating heating pool 12;

[0045] The circulating liquid flowing through the surface of the workpiece and into the inner wall of the liquid collecting tank 11 can be returned to the circulating heating tank 12 through the pump between the liquid collecting tank 11 and the circulating heating tank 12, thereby realizing the recycling of the circulating liquid.

[0046] The clamping plate 13 is located on the left side of the clamping plate 21. The number of the clamping plates 13 and 21 is eight, and they are all evenly distributed around the outer surface of the metal cone mold 4. The multiple groups of clamping plates 13 and the multiple groups of clamping plates 21 respectively form two circular structures of one large and one small size.

[0047] The clamping plate 21 is responsible for clamping the workpiece that has just been installed on the surface of the metal conical mold 4. When the metal conical mold 4 continues to move to the right, the workpiece is expanded through the thicker part on the left side of the metal conical mold 4. At this time, the clamping plate 21 and the connecting column 20 begin to move to the side away from the axis of the metal conical mold 4 under the action of the cylinder 16, thereby making way for the workpiece after expansion, and the clamping plate 13 replaces the clamping plate 21 to clamp and fix the workpiece.

[0048] The axes of the connecting columns 20 are perpendicular to the axial direction of the metal conical mold 4. There are eight groups of connecting columns 20, which are evenly distributed around the outer surface of the metal conical mold 4.

[0049] The axis of the connecting column 20 coincides with the radial line of the fixing ring 15 and the metal conical mold 4. Under the pushing action of the cylinder 16, the connecting ring 17 and the limit frame 18, the connecting column 20 can move back and forth along the radial line of the fixing ring 15, thereby realizing the clamping function of the workpiece.

[0050] The number of the cylinders 16 is four and they are equidistantly distributed around the outer surface of the metal cone die 4. The connecting ring 17 is located between the clamping plate 13 and the fixing ring 15.

[0051] The number of cylinders 16 is reduced to four groups, and under the guidance of the support column 14, the connecting ring 17 and the limit frame 18 can achieve stable horizontal movement.

[0052] The connecting ring 17 is an annular structure, and the supporting column 14 is adapted to penetrate the surface of the connecting ring 17;

[0053] The connecting ring 17 of the annular structure connects the cylinder 16 and the limit frame 18 and is guided and supported by the support column 14, so that the movement of the limit frame 18 and the connecting column 20 is more stable.

[0054] The limiting frame 18 is distributed obliquely as a whole, and the long side of the limiting frame 18 forms an angle of 30° with the axis of the metal conical mold 4;

[0055] like Figure 3 As shown, the inclined limiting frame 18 uses the positioning groove 19 provided inside it to limit the limiting wheel 23. Figure 3 In the embodiment, if the cylinder 16 drives the connecting ring 17 and the limit frame 18 to move to the right, it will apply pressure to the limit wheel 23 through the inner wall of the positioning groove 19. Since the connecting column 20 is limited by the fixing ring 15 so that it can only move along the radial line of the fixing ring 15, the limit wheel 23 can only move downward and drive the fixed block 22, the connecting column 20 and the clamping plate 21 to move toward the side of the clamped workpiece, that is, to realize the clamping function, and the limit wheel 23 is slidably installed on the inner wall of the positioning groove 19, which can significantly reduce friction and improve the durability of the device.

[0056] The longitudinal cross-section of the guide plate 9 is in the shape of a "human", and rectangular protrusions are provided on both the front and rear sides of the guide plate 9;

[0057] like Figure 4As shown, the circulating liquid flows along the inside of the liquid inlet pipe 8 to the upper surface of the guide plate 9. Since rectangular protrusions are provided on the front and rear sides of the guide plate 9, the circulating liquid on the upper surface of the guide plate 9 can flow downward evenly at the same time, avoiding the uneven phenomenon of more circulating liquid in the middle and less on both sides.

[0058] Working principle:

[0059] When the device is working, first, the workpiece is placed in the circulating heating pool 12 filled with circulating fluid. The circulating heating pool 12 has its own heating function, so that the workpiece is boiled and softened. Then, the softened workpiece is installed on the device, and one end of the workpiece is aligned with the metal conical mold 4 and sleeved on it. The cylinder 16 is started and drives the connecting ring 17 and the limit frame 18 to move to the right. The support column 14 provides support and guidance for it. At this time, Figure 3 As shown, the limiting frame 18 moving to the right presses and limits the limiting wheel 23, so that the limiting wheel 23 and the fixing block 22 drive the connecting column 20 and the second clamping plate 21 to move toward the axis of the metal conical mold 4, and drive the multiple groups of second clamping plates 21 to move synchronously toward the outside of the workpiece and complete the clamping;

[0060] Then, the oil cylinder 3 is started, and the metal conical die 4 is driven to move to the right, and the part with a larger diameter at the left end of the metal conical die 4 is used to expand the workpiece to complete the hole expansion operation. When the conical transition slope on the surface of the metal conical die 4 moves to the inner position of the clamping plate 21, the cylinder 16 is started to drive the connecting ring 17 and the limit frame 18 to the left to reset, and the positioning groove 19 is used to drive the limit wheel 23 to move upward and adapt to the part with a larger diameter on the outer surface of the metal conical die 4. At this time, the diameter of the circle surrounded by the clamping plate 13 and the clamping plate 21 is the same, thereby jointly completing the clamping of the workpiece.

[0061] Finally, when the oil cylinder 3 drives the metal cone mold 4 to the right to move to the maximum stroke, it stops moving, and the circulating liquid is connected to the liquid inlet pipe 8 and sent to the inner cavity of the drainage tank 6, as shown in FIG. Figure 4 As shown, the circulating liquid flows evenly along the front and rear sides of the upper surface of the guide plate 9 to the front and rear sides of the inner wall of the drainage trough 6. The circulating liquid flows evenly into the inner wall of the closing device 7 through the diversion strip 10, and finally falls to the surface of the workpiece, thereby completing the cooling and shaping of the workpiece. The circulating liquid flows downward along the surface of the workpiece and takes away the heat, and then flows back to the circulating heating pool 12 under the action of the connecting pipe and the pump.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A pipe expansion device for a retractable PE pipe, comprising a frame (1) and a mounting plate (2), wherein an oil cylinder (3) is mounted inside the frame (1), and a metal conical die (4) is mounted at the telescopic end of the oil cylinder (3), characterized in that: Also includes: The clamping mechanism comprises a plurality of clamping plates (13) and a plurality of supporting columns (14) fixedly mounted on the right side of the mounting plate (2), the right end of the supporting column (14) being fixedly connected to a fixing ring (15), the inner wall of the fixing ring (15) being movably sleeved with a plurality of connecting columns (20), one end of the connecting column (20) being fixedly mounted to a clamping plate (21), the other end of the connecting column (20) being fixedly mounted to a fixing block (22), the inner portion of the fixing block (22) being rotatably mounted with a limiting wheel (23), the right side of the mounting plate (2) being fixedly mounted to a plurality of cylinders (16), the telescopic end of the cylinder (16) being fixedly connected to a connecting ring (17), the right side of the connecting ring (17) being fixedly mounted to a limiting frame (18), the front and rear sides of the inner wall of the limiting frame (18) being provided with positioning grooves (19), the limiting wheel (23) being slidably mounted in the positioning groove (19), The limiting frame (18) is distributed in an inclined manner as a whole, and the long side of the limiting frame (18) forms an angle of 30° with the axis of the metal conical mold (4); A cooling mechanism comprises a mounting frame (5) mounted on the top of a frame (1) and a liquid collecting tank (11) located on the right side of the frame (1); a circulating heating pool (12) is placed behind the liquid collecting tank (11); a liquid drain trough (6) is fixedly mounted on the bottom of the mounting frame (5); a liquid inlet pipe (8) is fixedly connected to the top of the liquid drain trough (6); and the cooling mechanism sprays circulating liquid downward.

2. A pipe expansion device for a shrinkable PE pipe according to claim 1, characterized in that: A rectangular drain outlet is provided at the bottom of the drainage trough (6), a guide plate (9) is fixedly connected to the top of the inner wall of the drainage trough (6), and diversion strips (10) are provided horizontally and equidistantly on both the front and rear sides of the inner wall of the drainage trough (6).

3. A pipe expansion device for a shrinkable PE pipe according to claim 2, characterized in that: The front and rear sides of the bottom of the rectangular drain outlet are both fixedly connected with a sealer (7), and the distance between the two groups of sealers (7) is smaller than the width of the rectangular drain outlet.

4. A pipe expansion device for a shrinkable PE pipe according to claim 3, characterized in that: A communicating pipe and a pump are installed between the liquid collecting tank (11) and the circulating heating pool (12), and the communicating pipe and the pump are used to transport the circulating liquid in the liquid collecting tank (11) to the circulating heating pool (12).

5. A pipe expansion device for a shrinkable PE pipe according to claim 4, characterized in that: The clamping plate 1 (13) is located on the left side of the clamping plate 2 (21). The number of the clamping plate 1 (13) and the clamping plate 2 (21) are both eight groups, and are equidistantly distributed around the outer surface of the metal conical mold (4). Multiple groups of the clamping plate 1 (13) and multiple groups of the clamping plate 2 (21) respectively form two groups of circular structures of one large and one small size.

6. A pipe expansion device for a shrinkable PE pipe according to claim 5, characterized in that: The axes of the connecting columns (20) are perpendicular to the axial direction of the metal conical mold (4). The number of the connecting columns (20) is eight groups, and they are equidistantly distributed around the outer surface of the metal conical mold (4).

7. A pipe expansion device for a shrinkable PE pipe according to claim 6, characterized in that: The number of the cylinders (16) is four groups, and they are equidistantly distributed circumferentially toward the outer surface of the metal conical mold (4), and the connecting ring (17) is located between the clamping plate (13) and the fixing ring (15).

8. The pipe expansion device for a shrinkable PE pipe according to claim 7, characterized in that: The connecting ring (17) is an annular structure, and the supporting column (14) is adapted to penetrate the surface of the connecting ring (17).

9. A pipe expansion device for a shrinkable PE pipe according to claim 8, characterized in that: The longitudinal cross-section of the guide plate (9) is in the shape of a "human"; rectangular protrusions are provided on both the front and rear sides of the guide plate (9).

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