Aerodynamic spinning cooling system for thermoplastic pipe and cooling method

Abstract

The invention discloses a gas power self-spinning cooling system and method for thermoplastic pipes, and belongs to the field of pipeline inner wall cooling devices. The gas power self-spinning cooling system comprises an extrusion molding device, a vacuum sizing box, a self-spinning cooling device and a self-adaptive adjusting device; the spinning cooling device comprises a pull rod arranged in the thermoplastic pipe, a device body arranged on the pull rod in a sleeving manner and an air inlet pipeline for introducing airflow into the device body; the device body comprises an air inlet seat fixedly connected with the pull rod, a rotary air hood rotating relative to the air inlet seat and a sealing end cover, and the air inlet seat, the rotary air hood and the sealing end cover are mutually connected to form a closed circular ring column; the air inlet seat is rotationally connected with the rotary air hood; an air inlet is formed in the air inlet seat; an exhaust pipe is arranged in the rotary air hood; and the exhaust pipe is arranged at a non-axis position in the rotary gas hood. Compressed air is introduced into the pipe, so that the device can be rotated by using the compressed air as power, and the inner wall of the pipe is cooled by using the compressed air as a medium.

Description

Technical Field

[0001] The present invention relates to the field of pipeline inner wall cooling devices, in particular to a gas-powered self-rotating cooling system and cooling method for thermoplastic pipes. Background Art

[0002] During the production process of thermoplastic pipes, after the pipes are extruded from the die, they will immediately enter the vacuum sizing tank. In the vacuum sizing tank, negative pressure is used to adsorb the pipes onto the inner wall of the sizing sleeve, and at the same time, water mist is used to cool the outer wall of the pipes. Since the thermal conductivity coefficient of thermoplastic pipes is very low, for example, the thermal conductivity coefficient of PVC material is 0.14 - 0.16 W / (m·K), while that of medium carbon steel is 60 - 80 W / (m·K), and the difference between the two is about 500 times. Therefore, for thick-walled thermoplastic pipes, it takes an extremely long time for the inner wall temperature to reach below the decomposition temperature. For PVC materials, the processing temperature is much higher than its decomposition temperature, and this completely relies on heat stabilizers to ensure normal processing.

[0003] After the thermoplastic pipes are extruded and formed, it is also of extremely important significance to have a stable temperature after cooling, which is mainly reflected in the following aspects: 1. In terms of dimensional stability After the thermoplastic material is extruded and formed, its internal structure is in a relatively unstable state. If the temperature after cooling is not stable, the pipes will be subjected to uneven thermal stress during the cooling process.

[0004] 2. In terms of performance stability The molecular chain structure of the thermoplastic material will gradually be fixed during the cooling process. When the temperature is stable after cooling, the molecular chains of the material can be arranged in a relatively orderly manner. This helps to ensure the stability of the mechanical properties such as the tensile strength and bending strength of the pipes. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a gas-powered self-rotating cooling system and cooling method for thermoplastic pipes. By introducing compressed air into the pipes, the device can be rotated using the compressed air as power, and at the same time, the compressed air is used as a medium to cool the inner wall of the pipes. By controlling the opening of the electro-hydraulic proportional valve, the inner wall temperature of the thermoplastic pipes can be stably cooled to the expected temperature.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: A gas-powered self-rotating cooling system for thermoplastic pipes, comprising an extrusion molding device, a vacuum sizing tank arranged outside the thermoplastic pipes after extrusion molding, a self-rotating cooling device arranged inside the thermoplastic pipes after extrusion molding, and an adaptive adjustment device for controlling the rotation speed of the self-rotating cooling device; The spin cooling device includes a pull rod disposed inside a thermoplastic pipe, a device body sleeved on the pull rod, and an air inlet pipeline for introducing air flow into the device body; the device body includes an air inlet seat fixedly connected to the pull rod, a rotating air hood rotatably opposite to the air inlet seat, and a sealing end cover, and the air inlet seat, the rotating air hood, and the sealing end cover are connected to each other to form a sealed circular cylinder; the air inlet seat is rotationally connected to the rotating air hood; An air inlet is provided on the air inlet seat, and an exhaust pipe is provided inside the rotating air hood; the exhaust pipe is disposed at a non-axis position inside the rotating air hood; The adaptive adjustment device includes an electronically controlled proportional valve connected to the starting end of the air inlet pipeline, a centralized control unit for controlling the opening degree of the electronically controlled proportional valve, and an infrared temperature sensor disposed at the starting end of the pull rod.

[0007] A further improvement of the technical solution of the present invention lies in that: the air inlet seat includes an annular end face, a connecting pipe disposed on the inner circle of the end face, and an outer edge disposed on the outer circle of the end face; an air inlet is provided on the end face of the air inlet seat; the air inlet is connected to the air inlet pipeline; the connecting pipe is fixedly connected to the pull rod; a groove and a protrusion are sequentially provided on the upper surface of the outer edge, and an elastic retaining ring is provided on the groove.

[0008] A further improvement of the technical solution of the present invention lies in that: the rotating air hood includes a cylindrical body, a first inner edge provided at the front end of the cylindrical body, and a second inner edge provided at the rear end of the cylindrical body; an exhaust pipe is provided inside the cylindrical body; the first inner edge is clamped between the elastic retaining ring and the protrusion; the inner diameter of the first inner edge is larger than the outer diameter of the outer edge, and the rotating air hood can rotate relative to the air inlet seat; a sealing member is provided inside the rotating air hood, and the sealing member is a conical elastic shell-shaped member; one end of the sealing member is fixed to the air inlet seat by a screw, and the other end abuts against the first inner edge of the rotating air hood.

[0009] A further improvement of the technical solution of the present invention lies in that: the sealing end cover is fixed to the second inner edge of the rotating air hood by a screw; a sealing ring is provided between the end of the sealing end cover and the connecting pipe.

[0010] A further improvement of the technical solution of the present invention lies in that: the inlet of the exhaust pipe is provided on the circular diameter of the cross-section of the cylindrical body, and the distance from the center of the circle is greater than 3 / 4 of the radius, and the outlet of the exhaust pipe is provided on the cylindrical body.

[0011] A further improvement of the technical solution of the present invention lies in that: the extrusion molding device includes an extrusion die head disposed outside the unextruded thermoplastic pipe and an extrusion core die disposed outside the unextruded thermoplastic pipe.

[0012] A further improvement of the technical solution of the present invention lies in that: the vacuum sizing tank is cylindrical, and a plurality of cooling water sprays are provided on the inner wall.

[0013] A further improvement of the technical solution of the present invention lies in that: the data transmission mode of the infrared temperature sensor is wireless transmission; the centralized control unit is externally connected with a wireless receiving and transmitting device; the electronic control proportional valve is provided with a gas source inlet and is externally connected with a gas source.

[0014] A gas-powered spin cooling method for thermoplastic pipes includes the following steps: S1. The thermoplastic pipe passes through an extrusion molding device and enters a vacuum sizing tank after extrusion. The vacuum sizing tank uses negative pressure to adsorb the pipe onto the inner wall of the sizing sleeve and move forward. At the same time, cooling water is sprayed to cool the outer wall of the pipe. S2. The infrared temperature sensor collects the starting pipe section of the thermoplastic pipe after extrusion molding, measures the inner wall temperature in real time and transmits it to the centralized control unit. S3. The centralized control unit controls the flow rate of the air flow in the intake pipeline by adjusting the opening degree of the electronic control proportional valve, and further controls the opening degree of the electronic control proportional valve when the test point moves to the rotary cooling device, so that the rotary cooling device outputs a corresponding rotational speed.

[0015] A further improvement of the technical solution of the present invention lies in that: in S3, the centralized control unit controls the flow rate of the air flow in the intake pipeline by adjusting the opening degree of the electronic control proportional valve, which specifically includes the following steps: S31. When the temperature change slope K collected by the centralized control unit within the preset time period is within [-K1, K1] and has the same positive and negative signs, the centralized control unit takes the average temperature T within the preset time period a , and calculates the opening degree D of the electronic control proportional valve: D = A × (T a -T e ） where A is a proportionality coefficient, T e is the desired temperature, and K1 is the first slope, with a range of 0.1 to 0.5; S32. When the temperature change slope K collected by the centralized control unit within the preset time period is within [-K1, K1] and has different positive and negative signs, or the minimum value of K is within [-K2, -K1) or the maximum value of K is within (K1, K2], the opening degree D of the electronic control proportional valve is calculated by the PID control method:

[0016] where Kp is the proportional gain, Ki is the integral gain, Kd is the derivative gain, T is the real-time collected temperature, t is the preset time, and K2 is the second slope, with a range of 0.8 to 1; S33 When the minimum value of the temperature change slope K within the preset time period collected by the centralized control unit is in the range of [-K3, K2) or the maximum value of K is in the range of (K2, K3], immediately stop the production of thermoplastic pipes and scrap the corresponding pipe segments, where K3 is the third slope and its range is 2 to 10.

[0017] Due to the adoption of the above technical solutions, the technical progress achieved by the present invention is as follows: 1. In the present invention, by introducing compressed air into the interior of the pipe, the air flow will enter the exhaust pipe from the exhaust pipe inlet of the exhaust pipe, and then discharge from the exhaust pipe outlet until it blows onto the inner wall of the thermoplastic pipe. Since the exhaust pipe does not pass through the axis of the rotary air hood, during the process of gas discharge, its reaction force will generate a torque on the rotary air hood, thereby causing the rotary air hood to start rotating. The discharged gas can continuously cool the inner wall of the pipe by 360 degrees during the rotation of the rotary air hood, that is, using compressed air as the power to rotate the device and using compressed air as the medium to cool the inner wall of the pipe.

[0018] 2. The present invention ensures the sealing performance of the cooling device by using seals, sealing rings and snap rings. There is a seal between the air inlet seat and the rotary air hood. The seal is fixed to the air inlet seat by screws and is in close contact with the inner cavity of the rotary air hood to prevent gas leakage. And a snap ring is used to ensure that there is no axial displacement between the air inlet seat and the rotary air hood, so as to avoid disconnection. The sealing end cover is fixed to the rotary air hood by screws and can rotate therewith. There is a sealing ring between the sealing end cover and the air inlet seat to prevent gas leakage.

[0019] 3. The present invention continuously measures the temperature of the starting pipe segment A point of the thermoplastic pipe after extrusion molding within a preset time. When this pipe segment moves to the self-rotating cooling device, the centralized control unit adjusts the opening degree of the electro-control proportional valve according to the corresponding strategy, and then controls the rotation speed of the self-rotating cooling device, so as to stably cool the inner wall temperature of the thermoplastic pipe to the desired temperature. Description of the Drawings

[0020] Figure 1 is a sectional view of the gas-powered self-rotating cooling system for thermoplastic pipes in the present invention; Figure 2 is a front sectional view of the gas-powered self-rotating cooling device in the present invention; Figure 3 is a partial enlarged view of the gas-powered self-rotating cooling device in the present invention; Figure 4 is a side view of the gas-powered self-rotating cooling device in the present invention; Among them, 1. Tie rod, 2. Air inlet seat, 3. Rotating air hood, 4. Sealing end cover, 5. Air inlet, 6. Elastic retaining ring, 7. Sealing element, 8. Sealing ring, 9. Exhaust pipe, 10. Thermoplastic pipe, 11. Central control unit, 12. Electro-control proportional valve, 13. Air inlet pipeline, 14. Extrusion die, 15. Extrusion mandrel, 16. Infrared temperature sensor, 17. Vacuum sizing tank, 18. Wireless receiving and transmitting device, 19. Air source inlet, 20. Cooling water spray. Detailed implementation manners

[0021] The present invention will be further described in detail below with reference to the drawings and embodiments: In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0022] In addition, terms such as "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "several" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0023] As Figure 1 、 2 shown, a gas-powered self-rotating cooling system for thermoplastic pipes includes an extrusion molding device, a vacuum sizing tank 17 arranged outside the thermoplastic pipe after extrusion molding, a self-rotating cooling device arranged inside the thermoplastic pipe after extrusion molding, and an adaptive adjustment device for controlling the rotation speed of the self-rotating cooling device; The extrusion molding device includes an extrusion die 14 arranged outside the unextruded thermoplastic pipe and an extrusion mandrel 15 arranged outside the unextruded thermoplastic pipe; The vacuum sizing tank 17 is cylindrical, and several cooling water sprays 20 are arranged on the inner wall; As Figure 3As shown, the spin cooling device includes a pull rod 1 disposed inside a thermoplastic pipe 10, a device body sleeved on the pull rod 1, and an intake pipeline 13 for introducing air flow into the device body; the device body includes an intake seat 2, a rotating air hood 3, and a sealing end cover 4, and the intake seat 2, the rotating air hood 3, and the sealing end cover 4 are connected to each other to form a closed circular cylinder; the pull rod 1 is disposed at the center of the outlet of the extrusion molding device; The intake seat 2 includes an annular end face, a connecting pipe disposed on the inner circle of the end face, and an outer edge disposed on the outer circle of the end face; an air intake inlet 5 is disposed on the end face of the intake seat 2; the air intake inlet 5 is connected to the intake pipeline 13; the connecting pipe is fixedly connected to the pull rod 1; grooves and protrusions are sequentially disposed on the upper surface of the outer edge, and an elastic retaining ring 6 is disposed on the groove; As Figure 4 shown, the rotating air hood 3 includes a cylindrical body, a first inner edge disposed at the front end of the cylindrical body, and a second inner edge disposed at the rear end of the cylindrical body; an exhaust pipe 9 is disposed inside the cylindrical body; the first inner edge is clamped between the elastic retaining ring 6 and the protrusion; the inner diameter of the first inner edge is greater than the outer diameter of the outer edge, and the rotating air hood 3 can rotate relative to the intake seat 2; an exhaust pipe 9 is disposed inside the cylindrical body, the inlet of the exhaust pipe 9 is disposed on the circular horizontal diameter of the cross-section of the cylindrical body, and the distance from the center of the circle is greater than 3 / 4 of the radius, and the outlet of the exhaust pipe 9 is disposed on the cylindrical body; a sealing member 7 is further disposed inside the rotating air hood 3, and the sealing member 7 is a conical elastic shell-shaped member; one end of the sealing member 7 is fixed to the intake seat 2 by screws, and the other end abuts against the first inner edge of the rotating air hood 3, and is in close contact with the inner cavity of the rotating air hood 3 to prevent gas leakage; The sealing end cover 4 is fixed to the second inner edge of the rotating air hood 3 by screws; a sealing ring 8 is disposed between the end of the sealing end cover 4 and the connecting pipe; The adaptive adjustment device includes an electronically controlled proportional valve 12 connected to the starting end of the intake pipeline 13, a centralized control unit 11 for controlling the opening degree of the electronically controlled proportional valve 12, and an infrared temperature sensor 16 disposed at the starting end of the pull rod 1; the data transmission mode of the infrared temperature sensor 16 is wireless transmission; the centralized control unit 11 is externally connected to a wireless receiving transmitter 18; the electronically controlled proportional valve 12 is provided with a gas source inlet 19 and is externally connected to a gas source.

[0024] A gas dynamic spin cooling method for thermoplastic pipes includes the following steps: S1. The thermoplastic pipe 10 passes through an extrusion molding device, and after extrusion, it enters a vacuum sizing box 17. The vacuum sizing box 17 uses negative pressure to adsorb the pipe to the inner wall of the sizing sleeve and moves from the L end to the R end. At the same time, a cooling water spray 20 cools the outer wall of the pipe; S2. The infrared temperature sensor 16 collects the starting pipe section A point of the thermoplastic pipe 10 after extrusion molding, measures the inner wall temperature in real time, and transmits it to the centralized control unit 11; S3. The centralized control unit 11 controls the flow rate of the air flow in the intake pipe 13 by adjusting the opening degree of the electronically controlled proportional valve 12. Further, when the test point moves to the rotary cooling device, it controls the opening degree of the electronically controlled proportional valve 12 so that the spin cooling device outputs a corresponding rotational speed to achieve different cooling effects. The air flow is injected from the inlet of the intake seat 2 into the inner cavity of the cooling device. After the inner cavity of the rotary cooling device is filled with gas, the air flow enters the exhaust pipe 9 from the inlet of the exhaust pipe 9, and then is discharged from the outlet of the exhaust pipe 9 until it blows onto the inner wall of the thermoplastic pipe 10, continuously cooling the inner wall of the pipe by 360 degrees during the rotation of the rotary air hood 3. M is the rotation direction of the rotary air hood 3; In S3, the centralized control unit 11 controls the flow rate of the air flow in the intake pipe 13 by adjusting the opening degree of the electronically controlled proportional valve 12, which specifically includes the following steps: S31. When the slope K of the temperature change within the preset time period collected by the centralized control unit 11 is within [-K1, K1] and has the same positive and negative signs, since the change trend is single and the change amplitude is small, the centralized control unit takes the average temperature T within the preset time period a , and calculates the opening degree D of the electronically controlled proportional valve: D = A × (T a -T e ） where A is the proportional coefficient, T e is the expected temperature, K1 is the first slope, and the range is 0.1 - 0.5.

[0025] S32. When the slope K of the temperature change within the preset time period collected by the centralized control unit 11 is within [-K1, K1] and has different positive and negative signs, or the minimum value of K is within [-K2, -K1) or the maximum value of K is within (K1, K2], the opening degree D of the electronically controlled proportional valve is calculated by the PID control method:

[0026] where Kp is the proportional gain, Ki is the integral gain, Kd is the differential gain, T is the real-time collected temperature, t is the preset time, K2 is the second slope, and the range is 0.8 - 1; S33. When the minimum value of the slope K of the temperature change within the preset time period collected by the centralized control unit 11 is within [-K3, K2) or the maximum value of K is within (K2, K3], the production of the thermoplastic pipe is immediately stopped and the corresponding pipe section is invalidated, where K3 is the third slope and the range is 2 - 10.

[0027] Working principle: The cooling device is fixed to the pull rod 1 through the air inlet seat 2. The contact part between the air inlet seat 2 and the rotating air hood 3 adopts a clearance fit, so that they can rotate relative to each other. In addition, there is a seal 7 between the air inlet seat 2 and the rotating air hood 3. The seal 7 is fixed to the air inlet seat 2 by screws and is in close contact with the inner cavity of the rotating air hood 3 to prevent gas leakage. The seal 7 is a conical shell-shaped part, and its sealing performance is ensured by its own deformation; and as the gas source is input, the pressure inside the rotating air hood gradually increases; this pressure presses the seal 7 against the rotating air hood 3, and the greater the pressure, the greater the contact pressure between the seal 7 and the rotating air hood 3; thus effectively ensuring the sealing performance; in addition, the conical shell structure of the seal 7 ensures sealing by relying on structural deformation rather than elastic deformation, which effectively reduces the frictional resistance between the seal 7 and the rotating air hood 3 while ensuring sealing. Thus, the rotating air hood 3 can operate efficiently. And an elastic retaining ring 6 is used to ensure that there is no axial displacement between the air inlet seat 2 and the rotating air hood 3, so as to prevent disengagement. The sealing end cover 4 is fixed to the rotating air hood 3 by screws and can rotate with it. There is a sealing ring 8 between the sealing end cover 4 and the air inlet seat 2 to prevent gas leakage. There is an exhaust pipe 9 on the rotating air hood 3. The exhaust pipe 9 does not pass through the axis of the rotating air hood 3 and is far from the axis.

[0028] By adjusting the gas input pressure at the inlet 5, for example, from 1 bar to 10 bar, according to Bernoulli's theorem and the law of conservation of mass, it can be known that when the inlet area and the outlet area remain relatively unchanged, the outlet pressure will also increase accordingly. Bernoulli's theorem:

[0029] The product of the outlet pressure and the outlet area is the above-mentioned reaction force, thereby increasing the rotation speed of the rotating air hood 3, that is, the amount of gas sucked onto the inner wall of the pipe 10 within the same time period increases. When the moving speed of the thermoplastic pipe 10 is constant, the cooling air volume increases.

[0030] Since the exhaust pipe 9 does not pass through the axis of the rotating air hood 3, during the gas discharge process, its reaction force will generate a torque on the rotating air hood 3, thereby causing the rotating air hood 3 to start rotating; in this way, the discharged gas can continuously cool the inner wall of the pipe by 360 degrees during the rotation of the rotating air hood 3.

[0031] By continuously measuring the temperature of the starting pipe section A point of the thermoplastic pipe 10 after extrusion molding within a preset time, when this pipe section moves to the self-rotating cooling device, the centralized control unit 11 adjusts the opening of the electronically controlled proportional valve 12 according to the corresponding strategy, and then controls the rotation speed of the self-rotating cooling device, so as to stably cool the inner wall temperature of the thermoplastic pipe 10 to the desired temperature. Point B is the position of the thermoplastic pipe cooled to the desired temperature.

[0032] In summary, by introducing compressed air into the interior of the pipe, the present invention can not only use the compressed air as power to rotate the device, but also use the compressed air as a medium to cool the inner wall of the pipe.

Claims

1. A gas-powered self-rotating cooling system for thermoplastic pipes, characterized in that: It includes an extrusion molding device, a vacuum sizing box (17) arranged outside the thermoplastic pipe (10) after extrusion molding, a spin cooling device arranged inside the thermoplastic pipe (10) after extrusion molding, and an adaptive adjustment device for controlling the rotation speed of the spin cooling device; The spin cooling device includes a pull rod (1) arranged inside the thermoplastic pipe (10), a device body sleeved on the pull rod (1), and an air inlet pipeline (13) for introducing air flow into the device body; the device body includes an air inlet seat (2) fixedly connected to the pull rod (1), a rotating air hood (3) rotating relative to the air inlet seat (2), and a sealing end cover (4), and the air inlet seat (2), the rotating air hood (3), and the sealing end cover (4) are connected to form a closed circular cylinder; the air inlet seat (2) is rotationally connected to the rotating air hood (3); An air inlet (5) is arranged on the air inlet seat (2), and an exhaust pipe (9) is arranged inside the rotating air hood (3); the exhaust pipe (9) is arranged at a non-axis position inside the rotating air hood (3); The adaptive adjustment device includes an electronically controlled proportional valve (12) connected to the starting end of the air inlet pipeline (13), a centralized control unit (11) for controlling the opening of the electronically controlled proportional valve (12), and an infrared temperature sensor (16) arranged at the starting end of the pull rod (1).

2. The gas-powered self-rotating cooling system for thermoplastic pipes according to claim 1, characterized in that: The air inlet seat (2) includes an annular end face, a connecting pipe arranged on the inner circle of the end face, and an outer edge arranged on the outer circle of the end face; an air inlet (5) is arranged on the end face of the air inlet seat (2); the air inlet (5) is connected to the air inlet pipeline (13); the connecting pipe is fixedly connected to the pull rod (1); grooves and protrusions are sequentially arranged on the upper surface of the outer edge, and an elastic retaining ring (6) is arranged on the groove.

3. The gas dynamic self-rotating cooling system for thermoplastic pipes according to claim 2, characterized in that: The rotating air hood (3) includes a cylindrical body, a first inner edge arranged at the front end of the cylindrical body, and a second inner edge arranged at the rear end of the cylindrical body; an exhaust pipe (9) is arranged inside the cylindrical body; the first inner edge is clamped between the elastic retaining ring (6) and the protrusion; the inner diameter of the first inner edge is larger than the outer diameter of the outer edge, and the rotating air hood (3) can rotate relative to the air inlet seat (2); a sealing member (7) is arranged inside the rotating air hood (3), and the sealing member (7) is a conical elastic shell-shaped member; one end of the sealing member (7) is fixed to the air inlet seat (2) by screws, and the other end abuts against the first inner edge of the rotating air hood (3).

4. The gas dynamic self-rotating cooling system for thermoplastic pipes according to claim 3, wherein: The sealing end cover (4) is fixed to the second inner edge of the rotating air hood (3) by screws; a sealing ring (8) is arranged between the end of the sealing end cover (4) and the connecting pipe.

5. The gas dynamic self-rotating cooling system for thermoplastic pipes according to claim 3, characterized in that: The inlet of the exhaust pipe (9) is arranged on the circular diameter of the cross-section of the cylindrical body, and the distance from the center of the circle is greater than 3 / 4 of the radius, and the outlet of the exhaust pipe (9) is arranged on the cylindrical body.

6. The gas dynamic self-rotation cooling system for thermoplastic pipes according to claim 1, characterized in that: The extrusion molding device includes an extrusion die head (14) arranged outside the unextruded thermoplastic pipe and an extrusion core die (15) arranged outside the unextruded thermoplastic pipe.

7. The gas dynamic spin cooling system for thermoplastic pipes according to claim 1, wherein: The vacuum sizing box (17) is cylindrical, and a plurality of cooling water sprays (20) are arranged on the inner wall.

8. The gas-powered spin cooling system for thermoplastic pipes according to claim 1, wherein: The data transmission mode of the infrared temperature sensor (16) is wireless transmission; the centralized control unit (11) is externally connected to a wireless receiving and transmitting device (18); the electro-control proportional valve (12) is provided with a gas source inlet (19) and is externally connected to a gas source.

9. A gas dynamic self-rotation cooling method for thermoplastic pipes, characterized in that: Using the gas-powered spin cooling system for thermoplastic pipes as described in any one of claims 1 to 8, includes the following steps: S1. The thermoplastic pipe (10) passes through an extrusion molding device and then enters a vacuum sizing tank (17). The vacuum sizing tank (17) uses negative pressure to adsorb the pipe onto the inner wall of the sizing sleeve and move it forward. At the same time, a cooling water spray (20) cools the outer wall of the pipe. S2. The infrared temperature sensor (16) collects the starting pipe section of the thermoplastic pipe (10) after extrusion molding, measures the inner wall temperature in real time, and transmits it to the centralized control unit (11). S3. The centralized control unit (11) controls the flow rate of the air flow in the intake pipe (13) by adjusting the opening degree of the electro-control proportional valve (12). Furthermore, when the test point moves to the rotary cooling device, it controls the opening degree of the electro-control proportional valve (12) to make the spin cooling device output a corresponding rotational speed.

10. The gas dynamic spin cooling method for thermoplastic pipes according to claim 9, characterized in that: In S3, the centralized control unit (11) controls the flow rate of the air flow in the intake pipe (13) by adjusting the opening degree of the electro-control proportional valve (12), specifically including the following steps: S31 When the temperature change slope K within the preset time period collected by the centralized control unit (11) is within [-K1, K1] and has the same positive and negative signs, the centralized control unit takes the average temperature T within the preset time period a , and calculates the opening degree D of the electro-control proportional valve: D = A×(T a -T e ） where A is a proportionality coefficient, T e is the desired temperature, and K1 is the first slope, with a range of 0.1 to 0.5; S32 When the slope K of the temperature change within the preset time period collected by the centralized control unit (11) is within [-K1, K1] and has different positive and negative values, or the minimum value of K is within [-K2, -K1), or the maximum value of K is within (K1, K2], the opening degree D of the electro-control proportional valve is calculated by the PID control method: ； Wherein, Kp is the proportional gain, Ki is the integral gain, Kd is the derivative gain, T is the real-time collected temperature, t is the preset time, and K2 is the second slope, with a range of 0.8 to 1; S33 When the minimum value of the slope K of the temperature change within the preset time period collected by the centralized control unit (11) is within [-K3, K2), or the maximum value of K is within (K2, K3], the production of the thermoplastic pipe is immediately stopped and the corresponding pipe section is invalidated, where K3 is the third slope, with a range of 2 to 10.

Images