Fixed-distance traction device for MPP pipe forming

Abstract

The invention relates to the technical field of pipe processing and forming, and discloses a fixed-distance traction device for MPP pipe forming, which comprises a rack, an adjusting traction conveying assembly is arranged on the rack in a lifting manner, the adjusting traction conveying assembly comprises two oppositely arranged conveyors and a conveying crawler belt mounted on the conveyors through a rotating shaft, and the fixed-distance traction device further comprises a desorption assembly, the desorption assembly is arranged in front of an inlet between the two conveying tracks and is used for scraping impurities on the surface of the dragged pipe; and the air injection assembly is arranged on the desorption assembly, and the air injection assembly is used for blowing away water on the surface of the dragged pipe and assisting the desorption assembly in cleaning impurities on the surface of the dragged pipe. According to the fixed-distance traction device for MPP pipe forming, pipes pretreated through cooperation of the desorption assembly and the air injection assembly enter the position between the conveying crawler belts, impurities can be effectively prevented from being pressed into the surfaces of the pipes through rubber pads or pressure of the conveying crawler belts in the conveying process, the longitudinal scratch generation probability is fundamentally reduced, and the production efficiency and the pipe quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe processing and forming, and particularly relates to a fixed-distance traction device for MPP pipe forming. Background Art

[0002] MPP pipe (modified polypropylene pipe) is a new type of plastic pipe. Due to its excellent high pressure resistance, high temperature resistance, impact resistance and insulation performance, it is widely used in construction projects such as laying pipelines and cables in special sections such as roads, railways, buildings, and under riverbeds. Its forming process mainly relies on the extrusion forming process, and the core processes include raw material treatment, melting and plasticization, die forming, cooling and shaping, traction and cutting, etc.

[0003] After long-term use of the sizing die, polymer degradation products (such as carbonized particles), mold release agent residues or chemical deposits of mold cleaners may remain on the inner wall. When the pipe contacts the inner wall of the sizing die, these viscous or granular impurities will be transferred to the pipe surface; when the pipe enters the cooling water (temperature 20 - 50°C) from the sizing die (temperature 180 - 220°C), the surface rapidly cools down to form a temperature gradient, and the suspended solids (granular impurities) in the cooling water are adsorbed on the pipe surface due to the thermophoretic effect.

[0004] To avoid abrasive wear (resulting in longitudinal scratches) caused by the surface impurities being pressed into the pipe by the rubber pad or track of the tractor under pressure, the traditional process requires manual wiping of the cooled pipe to clean the moisture and impurities on its surface, and then feeding the pipe into the tractor. Although it can reduce abrasive wear to a certain extent during the traction stage, it still exposes drawbacks in terms of efficiency, quality and other dimensions in actual production. Summary of the Invention

[0005] Technical Problem to be Solved Aiming at the above-mentioned drawbacks of the existing technology, the present invention provides a fixed-distance traction device for MPP pipe forming, which can effectively solve the problem in the existing technology that it is necessary to manually wipe the cooled pipe to clean the moisture and impurities on its surface, and then feed the pipe into the tractor, which seriously reduces the production efficiency.

[0006] Technical Solution To achieve the above object, the present invention is realized through the following technical solutions: The present invention provides a fixed-distance traction device for MPP pipe forming, including a frame, a regulating traction and conveying assembly is arranged on the frame in a lifting manner. The regulating traction and conveying assembly includes two relatively arranged conveyors, and conveying tracks installed on the conveyors through rotating shafts. It further includes: A desorption assembly, arranged in front of the inlet between the two conveying tracks, and the desorption assembly is used to scrape off the impurities on the surface of the towed pipe; A jet component is arranged on the desorption component. The jet component is used to blow off the moisture on the surface of the towed pipe and assist the desorption component to clean the impurities on its surface. An air supply component is connected to the jet component. The air supply component is used to continuously provide aerodynamic force for the jet component.

[0007] Further, the desorption component includes a fixed ring arranged on the outer wall of the frame through a connecting plate. A cleaning ring is arranged on one side of the fixed ring close to the conveying track. An adjusting semi-ring is rotatably arranged on one side of the cleaning ring close to the conveying track. Rotating columns are arranged at both ends of the adjusting semi-ring. Two positioning columns are arranged on the outer wall of the cleaning ring in an up-and-down staggered manner. A first desorption strip is connected between one of the rotating columns and one of the positioning columns, and a second desorption strip is connected between the other rotating column and the other positioning column.

[0008] Further, when the towed pipe does not pass into the inner side of the cleaning ring, the first desorption strip and the second desorption strip are in a parallel state. When the towed pipe is located between the first desorption strip and the second desorption strip, the first desorption strip and the second desorption strip are wound around the surface of the towed pipe.

[0009] Further, both the first desorption strip and the second desorption strip are made of elastic materials, and the cross-sections of the first desorption strip and the second desorption strip are right trapezoids.

[0010] Further, a positioning member is arranged on the outer side of the adjusting semi-ring. The positioning member includes a plurality of adjusting teeth arranged in an annular array on the outer wall of the adjusting semi-ring. A lifting rod is slidably arranged on the outer wall of the cleaning ring in the radial direction of the adjusting semi-ring. A clamping tooth is arranged at the bottom end of the lifting rod. A reset member is arranged between the clamping tooth and the outer wall of the cleaning ring.

[0011] Further, the jet component includes an air inlet cavity opened in the fixed ring. A plurality of air blowing holes are annularly arrayed on the inner side of the fixed ring, and the air blowing holes are communicated with the air inlet cavity. The air blowing holes are inclined towards the outside of the fixed ring.

[0012] Further, the air supply component includes a support seat arranged on the table top of the frame. A reciprocating lead screw is rotatably arranged on the support seat. The end of the reciprocating lead screw extends to the outside of the support seat, and a transmission wheel is fixedly sleeved at the end of the reciprocating lead screw. The transmission wheel is in transmission connection with the rotating shaft of any one of the conveying tracks through a sleeved belt.

[0013] Furthermore, an air supply cylinder is provided on the support base. A piston rod is slidably arranged inside the air supply cylinder. A moving block is arranged on the reciprocating lead screw in a threaded manner, and the moving block is slidably connected to the support base. The moving block is connected to the piston rod through a fixing rod, and a through groove for the movement of the fixing rod is formed on the air supply cylinder.

[0014] Furthermore, one-way exhaust valves are arranged at both ends of the air supply cylinder, and one-way intake valves are arranged on one side of the one-way exhaust valves. The one-way exhaust valves are communicated with the intake cavity through pipelines.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, a desorption assembly is arranged in front of the inlet of the conveying track. Impurities on the surface of the pipe are scraped off through physical contact, reducing pollutants from the source. The jet assembly uses the continuous aerodynamic force provided by the air supply assembly to blow off the moisture on the surface of the pipe and form an air flow to assist in removing the scraped impurities, avoiding the mixing and adhesion of moisture and impurities and the secondary accumulation of scraped impurities. The pipe pretreated by the cooperation of the desorption assembly and the jet assembly then enters between the conveying tracks, which can effectively prevent impurities from being pressed into the surface of the pipe by the rubber pad or the pressure of the conveying track during the conveying process, fundamentally reducing the probability of longitudinal scratches and improving the production efficiency and the quality of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of the fixing ring of the embodiment of the present invention; Figure 3 It is a schematic diagram of the structure when the first desorption strip and the second desorption strip are in a parallel state in the embodiment of the present invention; Figure 4 It is a schematic diagram of the structure when the first desorption strip and the second desorption strip are in a wound state in the embodiment of the present invention; Figure 5 It is a cross-sectional structure diagram of the first desorption strip and the second desorption strip in the embodiment of the present invention; Figure 6 It is a cross-sectional structure diagram of the fixing ring of the embodiment of the present invention; Figure 7 It is a cross-sectional structure diagram of the support base and the air supply cylinder in the embodiment of the present invention.

[0018] The reference numerals in the figure respectively represent: 100, frame; 200, adjustable traction conveying assembly; 201, conveyor; 202, conveying track; 300, desorption assembly; 301, fixed ring; 302, cleaning ring; 303, adjustable half-ring; 304, rotating column; 305, positioning column; 306, first desorption strip; 307, second desorption strip; 308, adjusting tooth; 309, lifting rod; 310, locking tooth; 311, resetting member; 400, air jet assembly; 401, intake cavity; 402, air blowing hole; 500, air supply assembly; 501, support seat; 502, reciprocating lead screw; 503, transmission wheel; 504, air supply cylinder; 505, piston rod; 506, moving block; 507, one-way exhaust valve; 508, one-way intake valve. Detailed implementation manners

[0019] For the purposes of making the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0020] The present invention will be further described below with reference to the embodiments.

[0021] Embodiment 1, referring to Figures 1-3 , which is the first embodiment of the present invention, provides a fixed-distance traction device for MPP pipe forming, including a frame 100. An adjustable traction conveying assembly 200 is arranged on the frame 100 in a lifting manner. The adjustable traction conveying assembly 200 includes two relatively arranged conveyors 201, and a conveying track 202 installed on the conveyors 201 through a rotating shaft. A rubber pad can be installed on the surface of the conveying track 202 to further increase the friction during conveying.

[0022] To prevent abrasive wear (resulting in longitudinal scratches) caused by the rubber pad or the conveying track 202 on the conveyor 201 pressing surface impurities into the pipe under pressure, the traditional process requires manual wiping of the cooled pipe to clean the moisture and impurities on its surface, and then feeding the pipe between two relatively arranged conveyors 201. Although it can reduce abrasive wear to a certain extent during the traction stage, it still exposes drawbacks in multiple dimensions such as efficiency and quality in actual production.

[0023] The fixed-distance traction device for MPP pipe forming further includes: a desorption component 300, installed in front of the entrance between two conveying tracks 202, and the desorption component 300 is used to scrape impurities on the surface of the pipe being traction; a jet component 400, installed on the desorption component 300, and the jet component 400 is used to blow off the moisture on the surface of the pipe being traction, and assist the desorption component 300 to clean the impurities on its surface; a gas supply component 500, connected to the jet component 400 and installed on the frame 100, and the gas supply component 500 is used to continuously provide aerodynamic force for the jet component 400.

[0024] Specifically, a desorption component 300 is arranged in front of the entrance of the conveying track 202, and impurities on the surface of the pipe are scraped off through physical contact, reducing pollutants from the source; the jet component 400 blows off the moisture on the surface of the pipe and forms an air flow to assist in removing the scraped-off impurities through the continuous aerodynamic force provided by the gas supply component 500, avoiding the mixing and adhesion of moisture and impurities and the secondary accumulation of scraped-off impurities; the pipe pretreated by the cooperation of the desorption component 300 and the jet component 400 then enters between the conveying tracks 202, which can effectively prevent the rubber pad or the pressure of the conveying track 202 from pressing the impurities into the surface of the pipe during the conveying process, fundamentally reducing the probability of longitudinal scratches and improving the production efficiency and the quality of the pipe.

[0025] Specifically, the desorption component 300 can be composed of elastic scraper frames symmetrically arranged on both sides of the pipe and arc-shaped scraper bodies. The scraper frames are fixed on the frame 100 through adjustable screws. The scraper bodies at the lower ends are made of wear-resistant rubber or metal materials. The cutting edges form an angle of 30° - 45° with the outer surface of the pipe and maintain slight contact, and the distance can be adjusted through the screws according to the diameter of the pipe.

[0026] The jet component 400 includes an annular jet pipe installed inside the scraper frame. Fan-shaped nozzles facing the surface of the pipe are evenly distributed on the pipe. The axis of the nozzle forms an inclination angle of 20° - 30° with the tangent of the pipe. The pipe is connected to the gas supply component 500 through a flexible air pipe.

[0027] The gas supply component 500 is composed of an air compressor, an air storage tank, a pressure regulating valve and a main gas supply pipe at the bottom of the frame 100. The compressed air generated by the compressor is stabilized by the air storage tank and the pressure is controlled by the regulating valve, and then is transported to the annular pipe through the main pipe and the branch air pipes, and high-speed air flow is ejected from the nozzles.

[0028] Specifically, during operation, the pipe is first scraped off the granular impurities on the surface by the scraper body, and at the same time, the residual moisture and the scraped-off fine impurities are blown off by the air flow ejected from the nozzles. The direction of the air flow is opposite to the traction direction of the pipe to enhance the peeling effect. The continuous air pressure of the gas supply component 500 ensures that the jet component 400 forms a stable air curtain.

[0029] Example 2, refer to Figures 1-5, which is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that the desorption component 300 includes a fixing ring 301 fixedly installed on the outer wall of the frame 100 through a connecting plate. A cleaning ring 302 is provided on one side of the fixing ring 301 close to the conveying track 202. An adjusting semi-ring 303 is rotatably installed on one side of the cleaning ring 302 close to the conveying track 202. Rotating columns 304 are provided at both ends of the adjusting semi-ring 303. Two positioning columns 305 are arranged on the outer wall of the cleaning ring 302 in an up-and-down staggered manner; a first desorption strip 306 is connected between one rotating column 304 and one positioning column 305, and a second desorption strip 307 is connected between the other rotating column 304 and the other positioning column 305. And the second desorption strip 307 is at a distance equal to the thickness of the conveying track 202 closer to the conveying track 202 than the first desorption strip 306, so as to avoid obstruction when the two are wound later.

[0030] Refer to Figure 3 and Figure 4 , when the pipe to be towed has not passed into the inner side of the cleaning ring 302, the first desorption strip 306 and the second desorption strip 307 are in a parallel state; when the pipe to be towed is located between the first desorption strip 306 and the second desorption strip 307, the first desorption strip 306 and the second desorption strip 307 are wound around the surface of the pipe to be towed.

[0031] Specifically, when the pipe has not entered the cleaning ring 302, the adjusting semi-ring 303 maintains its initial position under the action of gravity (as Figure 3 shown), so that the first desorption strip 306 and the second desorption strip 307 are in a parallel state (the distance is slightly larger than the outer diameter of the pipe); when the pipe enters the desorption component 300 from the cooling process, the operator manually pushes the adjusting semi-ring 303 to rotate axially according to the diameter of the pipe, driving the rotating column 304 to swing in an arc with the positioning column 305 as the fulcrum, so that the two desorption strips automatically open and close with the diameter of the pipe, and finally fit around the outer surface of the pipe in an annular belt shape. At this time, the first desorption strip 306 first contacts the surface of the pipe and scrapes off the impurities on the upper half of the pipe, and then the following second desorption strip 307 scrapes off the impurities on the lower half of the pipe.

[0032] Refer to Figure 5 , both the first desorption strip 306 and the second desorption strip 307 are made of elastic materials, and the cross-sections of the first desorption strip 306 and the second desorption strip 307 are right trapezoids.

[0033] Specifically, the deformation characteristics of the elastic material enable the first desorption strip 306 and the second desorption strip 307 to more automatically adjust to pipes of different diameters; their cross-sections are set to a right-angled trapezoid, so that the bevel serves as the main action surface for scraping impurities, and forms a progressive contact with the surface of the pipe. When the desorption strip moves with the pipe, the impurities first contact the bevel, and the normal component of force generated by the bevel pushes the impurities outward along the bevel, so that the impurities are separated from the pipe surface along the path from the bevel to the horizontal plane (the plane where the short top side of the right-angled trapezoid is located), avoiding the extension of scratches caused by the impurities sliding in the tangential direction; the impurities guided by the bevel are pushed to the horizontal plane (short top side area) of the right-angled trapezoid, which is perpendicular to the axis of the pipe, forming an impurity collection area for subsequent unified cleaning.

[0034] Reference Figure 3 and Figure 4 A positioning piece is installed on the outer side of the adjusting half ring 303, and the positioning piece includes a plurality of adjusting teeth 308 connected to the outer wall of the adjusting half ring 303 in a ring array. A lifting rod 309 is slidably installed on the outer wall of the cleaning ring 302 along the radial direction of the adjusting half ring 303, and a locking tooth 310 is fixedly installed on the bottom end of the lifting rod 309. A reset piece 311 is connected between the locking tooth 310 and the outer wall of the cleaning ring 302.

[0035] Specifically, when the adjusting half ring 303 needs to be adjusted according to the change in the diameter of the pipe, the adjusting tooth 308 rotates synchronously with the adjusting half ring 303, and at the same time, the lifting rod 309 is pulled upward, and the reset member 311 is compressed, so that the locking tooth 310 is away from the adjusting tooth 308 to facilitate its rotation adjustment. When the first desorption strip 306 and the second desorption strip 307 are completely wrapped around the surface of the pipe, the lifting rod 309 is released, so that the locking tooth 310 is embedded in the tooth groove of the two adjacent adjusting teeth 308 under the reset thrust of the reset member 311, forming a rigid positioning, locking the current angle of the adjusting half ring 303, and preventing the angle of the adjusting half ring 303 from changing due to vibration during traction, and the first desorption strip 306 and the second desorption strip 307 are unstably attached to the surface of the pipe.

[0036] Specifically, the reset member 311 is preferably a compression spring or a metal spring that can withstand the radial compression force of the adjustment half ring 303. The remaining structure is the same as that of the first embodiment.

[0037] Example 3, reference Figures 1-7 , which is the third embodiment of the present invention. This embodiment is different from the second embodiment in that: the jet assembly 400 includes an air inlet cavity 401 opened in the fixing ring 301, and a plurality of blowing holes 402 are opened in a circular array on the inner side of the fixing ring 301, and the blowing holes 402 are connected to the air inlet cavity 401; the blowing holes 402 are inclined toward the outer side of the fixing ring 301.

[0038] Specifically, the air inlet cavity 401 within the fixed ring 301 receives compressed air from the air supply assembly 500, and high-speed airflows are ejected through the annular array of air blowing holes 402 (tilted outward). When the airflows contact the surface of the pipe, large particle impurities are first stripped off by using inertial force and aerodynamic force. For some particles that adhere firmly, the airflows impact to loosen them, reducing the scraping resistance of the subsequent desorption strips and avoiding excessive wear of the first desorption strip 306 and the second desorption strip 307 caused by rigid contact of large particles.

[0039] Referring to Figure 7 , the air supply assembly 500 includes a support base 501 fixedly mounted on the tabletop of the frame 100. A reciprocating lead screw 502 is rotatably mounted on the support base 501 through a bearing. The end of the reciprocating lead screw 502 extends to the outside of the support base 501, and a transmission wheel 503 is fixedly sleeved on the end of the reciprocating lead screw 502. The transmission wheel 503 is drivingly connected to the rotating shaft of any one of the conveying tracks 202 through a sleeved belt; a gas supply cylinder 504 is fixedly mounted on the support base 501. A piston rod 505 is slidably arranged within the gas supply cylinder 504. A moving block 506 is threadedly mounted on the reciprocating lead screw 502, and the moving block 506 is slidably connected to the support base 501. The moving block 506 is connected to the piston rod 505 through a fixing rod ( Figure 7 shown in, but not labeled), and a through groove for the movement of the fixing rod is formed on the gas supply cylinder 504.

[0040] Specifically, the rotating shaft of the conveying track 202 drives the transmission wheel 503 to rotate through the belt, and further drives the reciprocating lead screw 502 to rotate around the bearing of the support base 501. Through the screw pair, the circular motion of the reciprocating lead screw 502 is converted into the linear reciprocating motion of the moving block 506. Under the connection action of the fixing rod, the piston rod 505 makes a piston motion within the gas supply cylinder 504, realizing that the gas supply cylinder 504 continuously provides aerodynamic force for the air inlet cavity 401 without the need for an additional power source.

[0041] Referring to Figure 7 , one-way exhaust valves 507 are installed at both ends of the gas supply cylinder 504, and one-way intake valves 508 are installed on one side of the one-way exhaust valves 507. The one-way exhaust valves 507 are connected to the air inlet cavity 401 through pipelines, and the one-way intake valves 508 allow outside air to enter the gas supply cylinder 504 unidirectionally.

[0042] Specifically, when the piston rod 505 moves to the right, the volume of the left chamber of the air supply cylinder 504 increases to form a negative pressure. The left one-way intake valve 508 automatically opens, and the outside air enters the left chamber through the left one-way intake valve 508. The right one-way intake valve 508 closes and the one-way exhaust valve 507 opens to ensure that the gas is sucked in and discharged into the intake chamber 401 unidirectionally. When the piston rod 505 moves to the left, the volume of the left chamber shrinks, the left one-way intake valve 508 closes, and the left one-way exhaust valve 507 opens. The air originally stored in the left chamber is discharged into the intake chamber 401 through the pipeline. At this time, a negative pressure is generated in the right chamber due to the increase in volume, and the right one-way intake valve 508 opens to suck in air, preparing for the next cycle. The independent air chambers at both ends of the air supply cylinder 504 form an alternating intake-exhaust mode. Each reciprocation of the piston completes two air supplies (the right chamber intakes air when the left chamber exhausts, and the left chamber intakes air when the right chamber exhausts), ensuring the continuity of the air flow output, so that the air flow can continuously blow to the surface of the pipe to remove moisture and assist in cleaning impurities. The remaining structure is the same as that of Embodiment 2.

[0043] Combining Embodiments 1-3, the working principle of the present invention is as follows: The present invention drives the driving wheel 503 of the air supply assembly 500 through the rotating shaft of the conveying track 202, converts the circular motion into the linear reciprocating motion of the piston rod 505 through the reciprocating lead screw 502, and realizes double-chamber alternating air supply through the one-way intake valve 508 and the one-way exhaust valve 507 at both ends of the air supply cylinder 504, providing continuous aerodynamic force synchronized with the traction speed for the jetting assembly 400. The inclined blow holes 402 of the jetting assembly 400 use high-speed air flow to pre-strip large particle impurities on the surface of the pipe and loosen the adhesives, and blow off the residual moisture on the surface of the pipe. Subsequently, the first desorption strip 306 and the second desorption strip 307 of the desorption assembly 300 are adjusted to fit the surface of the pipe in advance through the adjustment half-ring 303. The inclined surfaces of the first desorption strip 306 and the second desorption strip 307 push the impurities outwards to the horizontal plane, so as to completely clean the impurities and moisture on the surface of the pipe, avoid the pressure of the rubber pad or the conveying track 202 from pressing the impurities into the surface, fundamentally reduce the probability of longitudinal scratches, and improve the production efficiency and the quality of the pipe.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the protection scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A fixed-distance traction device for MPP pipe molding, comprising a frame (100), wherein an adjustable traction and conveying assembly (200) is arranged on the frame (100) in a lifting manner. The adjustable traction and conveying assembly (200) includes two conveyors (201) arranged oppositely, and a conveying track (202) installed on the conveyors (201) through a rotating shaft. It is characterized in that, Further comprising: A desorption assembly (300), arranged in front of the entrance between two conveying tracks (202), the desorption assembly (300) being used for scraping impurities on the surface of the towed pipe; An air jet assembly (400), arranged on the desorption assembly (300), the air jet assembly (400) being used for blowing off the moisture on the surface of the towed pipe and assisting the desorption assembly (300) to clean the impurities on its surface; An air supply assembly (500), connected to the air jet assembly (400), the air supply assembly (500) being used for continuously providing aerodynamic force for the air jet assembly (400).

2. The constant-distance traction device for MPP pipe forming according to claim 1, wherein, The desorption assembly (300) includes a fixed ring (301) arranged on the outer wall of the frame (100) through a connecting plate. A cleaning ring (302) is arranged on one side of the fixed ring (301) close to the conveying track (202). An adjusting semi-ring (303) is rotatably arranged on one side of the cleaning ring (302) close to the conveying track (202). Rotating columns (304) are arranged at both ends of the adjusting semi-ring (303). Two positioning columns (305) are arranged on the outer wall of the cleaning ring (302) in an upper and lower offset manner; A first desorption strip (306) is connected between one of the rotating columns (304) and one of the positioning columns (305), and a second desorption strip (307) is connected between the other rotating column (304) and the other positioning column (305).

3. The constant-distance traction device for MPP pipe forming according to claim 2, characterized in that, When the towed pipe has not passed into the inner side of the cleaning ring (302), the first desorption strip (306) and the second desorption strip (307) are in a parallel state; When the towed pipe is located between the first desorption strip (306) and the second desorption strip (307), the first desorption strip (306) and the second desorption strip (307) are wound around the surface of the towed pipe.

4. The constant-spacing traction device for MPP pipe forming according to claim 3, wherein, Both the first desorption strip (306) and the second desorption strip (307) are made of elastic materials, and the cross-sections of the first desorption strip (306) and the second desorption strip (307) are right-angled trapezoids.

5. The constant-distance traction device for MPP pipe forming according to claim 4, characterized in that, A positioning member is arranged on the outer side of the adjusting semi-ring (303). The positioning member includes a plurality of adjusting teeth (308) arranged in an annular array on the outer wall of the adjusting semi-ring (303). A lifting rod (309) is slidably arranged on the outer wall of the cleaning ring (302) in the radial direction of the adjusting semi-ring (303). A locking tooth (310) is arranged at the bottom end of the lifting rod (309). A reset member (311) is arranged between the locking tooth (310) and the outer wall of the cleaning ring (302).

6. The fixed-distance traction device for MPP pipe forming according to claim 2, characterized in that, The air jet assembly (400) includes an air inlet cavity (401) opened in the fixed ring (301). A plurality of air blowing holes (402) are annularly and arrayedly opened on the inner side of the fixed ring (301), and the air blowing holes (402) are communicated with the air inlet cavity (401); The air blowing holes (402) are inclined towards the outer side of the fixed ring (301).

7. The constant-distance traction device for MPP pipe forming according to claim 6, characterized in that, The air supply assembly (500) includes a support base (501) disposed on the tabletop of the frame (100). A reciprocating lead screw (502) is rotatably disposed on the support base (501). The end of the reciprocating lead screw (502) extends to the outside of the support base (501), and a transmission wheel (503) is fixedly sleeved on the end of the reciprocating lead screw (502). The transmission wheel (503) is drivingly connected to the rotating shaft of any one of the conveying tracks (202) through a sleeved belt.

8. The constant-distance traction device for MPP pipe forming according to claim 7, characterized in that, An air supply cylinder (504) is disposed on the support base (501). A piston rod (505) is slidably disposed in the air supply cylinder (504). A moving block (506) is threadedly disposed on the reciprocating lead screw (502), and the moving block (506) is slidably connected to the support base (501). The moving block (506) is connected to the piston rod (505) through a fixed rod, and a through groove for the movement of the fixed rod is formed on the air supply cylinder (504).

9. The fixed-distance traction device for MPP pipe forming according to claim 8, characterized in that, One-way exhaust valves (507) are disposed at both ends of the air supply cylinder (504), and a one-way intake valve (508) is disposed on one side of the one-way exhaust valve (507). The one-way exhaust valve (507) is communicated with the intake cavity (401) through a pipeline.

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