Device and method for manufacturing high-temperature-resistant PE-RT (polyethylene of raised temperature resistance) pipe

Abstract

The invention discloses a high-temperature-resistant PE-RT pipe manufacturing device and method. The device comprises a feeding and drying module, a plasticizing and extruding module, a forming die head module, a traction module, a cutting module and a collecting module, and is sequentially provided with a first thermal sizing section, a second slow cooling sizing section, a third uniform temperature stress releasing section and a fourth final cooling section in the pipe conveying direction. An online detection module is arranged to collect the outer diameter, the ovality, the wall thickness, the surface layer temperatures T1 and T2 of the first temperature detection position and the second temperature detection position, the traction tension Ft and the sizing vacuum degree Pv. The control module carries out fusion calculation according to a residual stress characterization index S based on a detection value, takes S as a main control quantity to adjust temperature control parameters of a slow cooling sizing section and a uniform-temperature stress release section in a linkage manner, and cooperatively adjusts the sizing vacuum degree and the traction speed under the constraint of a size window, so that closed-loop coordinated control of a temperature range and stress is realized, and the temperature range and the stress are controlled. The product consistency and the high-temperature working condition stability are improved.

Description

Technical Field

[0001] This invention relates to the field of extrusion molding production line technology, specifically to a high-temperature resistant PE-RT pipe manufacturing apparatus and method. Background Technology

[0002] Existing PE-RT pipes are typically manufactured continuously using extrusion molding production lines. These lines generally include extruders, forming dies, vacuum sizing chambers, cooling water tanks, traction devices, and cutting devices. The forming and sizing processes rely primarily on setting parameters such as sizing vacuum level, cooling water temperature, and traction speed. Since the cooling and sizing process after forming often uses a single or fixed temperature control method, and online monitoring tends to focus on dimensional indicators such as outer diameter and wall thickness, it lacks comprehensive characterization and coordinated adjustment of state variables closely related to residual stress formation, such as temperature gradient, cooling rate, traction tension, and vacuum constraint. This results in difficulty in stably reproducing the cooling temperature range when production line conditions fluctuate. The superposition of traction adjustment and vacuum constraint may introduce stress disturbances, leading to situations where dimensions meet standards but residual stress fluctuates significantly, and batch consistency is insufficient. This affects the stability and reliability of the products under high-temperature use or thermal cycling conditions. Summary of the Invention

[0003] This invention provides an apparatus and method for manufacturing high-temperature resistant PE-RT pipes.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] A high-temperature resistant PE-RT pipe manufacturing device includes a feeding and drying module, a plasticizing and extrusion module, a forming die head module, a traction module, a cutting module and a collection module connected in sequence, and also includes a multi-section sizing-temperature-temperature-stress relief module, an online detection module and a control module arranged in sequence along the pipe conveying direction;

[0006] The multi-segment sizing-temperature regulation-stress relief module sequentially includes a first hot sizing section, a second slow cooling sizing section, a third temperature equalization and stress relief section, and a fourth final cooling section, wherein:

[0007] The first hot sizing section includes a hot sizing box with a vacuum sizing cavity and a first temperature control circuit connected to the hot sizing box.

[0008] The second slow cooling and sizing section includes a slow cooling and sizing box with an independent vacuum degree adjustment circuit and a second temperature control circuit connected to the slow cooling and sizing box;

[0009] The third temperature equalization and stress relief section includes the temperature equalization and stress relief channel and its temperature control actuator;

[0010] The fourth final cooling section includes the final cooling water tank and its temperature control actuator;

[0011] The online detection module includes at least: an outer diameter and ellipticity detection unit, a wall thickness detection unit, a first temperature detection unit, a second temperature detection unit, a traction tension detection unit, and a vacuum detection unit. The first temperature detection unit is located at the outlet of the first hot sizing section to detect the surface temperature T1 of the pipe, and the second temperature detection unit is located at the outlet of the second slow cooling sizing section to detect the surface temperature T2 of the pipe.

[0012] The control module is connected to the online detection module, the second temperature control loop, the third temperature-relieving stress section temperature control actuator, the first hot sizing section vacuum adjustment loop, and the traction module drive actuator signal, and is configured to: calculate the residual stress characterization index S based on the online detection value, and use S as the main control quantity to perform linkage temperature adjustment on the second slow cooling sizing section and the third temperature-relieving stress section, while simultaneously adjusting the vacuum degree and / or traction speed of the first hot sizing section in a coordinated manner under the constraints that the outer diameter, ellipticity, and wall thickness are within a preset size window;

[0013] The residual stress characterization index S is calculated according to the following formula:

[0014]

[0015] In the formula: ; ;

[0016] L is the axial distance between the first temperature detection position and the second temperature detection position;

[0017] For traction speed;

[0018] This is the measured value of traction tension;

[0019] This is the measured value of vacuum degree during sizing;

[0020] This is a pre-defined positive normalization constant; These are preset weighting coefficients.

[0021] In a specific embodiment, the first temperature control loop and the second temperature control loop respectively include a circulating pump, a heat exchanger and a mixing valve, and the control module achieves closed-loop temperature control of the corresponding segment by adjusting the opening degree of the mixing valve and the speed of the circulating pump.

[0022] In a specific embodiment, the second slow cooling sizing section is divided into at least two slow cooling temperature zones arranged sequentially along the conveying direction. Each slow cooling temperature zone has an independent temperature acquisition point and an independent temperature control actuator to form a segmented slow cooling temperature drop curve.

[0023] In a specific embodiment, the temperature-equalizing stress-relieving channel of the third temperature-equalizing stress-relieving section is any one or a combination of a hot air channel, an infrared heating channel, or a circulating fluid temperature-equalizing channel, and the control module links the equivalent residence time of the temperature-equalizing stress-relieving section with the traction speed to achieve short-term temperature-equalizing stress relief under continuous traction.

[0024] In a specific embodiment, the online detection module further includes a cooling medium temperature detection unit and a flow detection unit. The control module uses the cooling medium temperature and flow rate as feedback or feedforward quantities for the temperature control of the second slow cooling sizing section to reduce temperature control lag caused by environmental fluctuations.

[0025] In a specific embodiment, the control module is equipped with a traction speed change rate limiting strategy, which ensures that the change in the traction speed setpoint within any control cycle does not exceed a preset threshold, thereby suppressing secondary stress input and control oscillations caused by traction adjustment.

[0026] In a specific embodiment, the control module adopts a coordinated control logic of "stress priority and size constraint": when S exceeds the preset stress window, the temperature control setting value of the second slow cooling sizing section and the temperature control setting value of the third uniform temperature stress relief section are adjusted first to bring S back into the window; when there are still deviations in outer diameter, ellipticity or wall thickness within the stress window, the size deviation is eliminated by adjusting the vacuum setting value of the first hot sizing section and the traction speed setting value.

[0027] A method for manufacturing high-temperature resistant PE-RT pipe, using the aforementioned high-temperature resistant PE-RT pipe manufacturing apparatus, includes: plasticizing and extruding PE-RT raw material and forming a pipe blank through a forming die; and sequentially passing the pipe blank through a first hot sizing section, a second slow cooling sizing section, a third uniform temperature stress relief section, and a fourth final cooling section before traction, cutting, and collection.

[0028] During the manufacturing process, outer diameter / ellipticity, wall thickness, T1, T2, Ft, Pv, and traction speed v are collected, and S is calculated according to the core formula. Based on S, the second slow cooling sizing section and the third uniform temperature stress relief section are linked for temperature adjustment, and the vacuum degree and traction speed of the first hot sizing section are coordinated under the constraint of the size window.

[0029] In a specific embodiment, when S exceeds the preset stress window, the control module triggers at least one handling strategy: increasing the temperature control setting value of the second slow cooling sizing section to reduce the temperature drop rate R and reduce ΔT, and increasing the temperature control setting value of the third uniform temperature stress relief section to enhance the uniform temperature stress relief effect.

[0030] This invention establishes a continuous and controllable temperature process flow by sequentially setting a first hot sizing section, a second slow cooling sizing section, a third temperature equalization and stress relief section, and a fourth final cooling section along the conveying direction after PE-RT pipe forming. It combines this with an online detection module to collect key state parameters such as outer diameter, surface temperatures T1 / T2 at two locations, traction tension Ft, and sizing vacuum degree Pv. The control module performs normalized and fused calculations according to the core formula of the residual stress characterization index S, using S as the main control variable to adjust the temperature control parameters of the second slow cooling sizing section and the third temperature equalization and stress relief section. Simultaneously, under dimensional window constraints, it coordinates the adjustment of sizing vacuum degree and traction speed and applies a traction change rate limitation strategy. Therefore, even under conditions such as production line speed fluctuations, ambient temperature changes, or melt state disturbances, it can still achieve controlled convergence of temperature gradient and cooling rate, reducing the secondary stress input introduced by traction and vacuum constraints. This simultaneously improves the dimensional stability and batch consistency of the pipe, effectively suppresses residual stress fluctuations, and thus enhances the stability and reliability of the product under high-temperature use and thermal cycling conditions. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 The diagram shown is a flowchart of the coordinated control logic of the present invention (stress priority, size constraint, traction speed limit).

[0033] Figure 2 The diagram shown is a block diagram of the control system of the present invention. Detailed Implementation

[0034] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0035] Example 1

[0036] The following detailed description of the high-temperature resistant PE-RT pipe manufacturing apparatus and its control method according to a specific embodiment further illustrates the present invention.

[0037] The high-temperature resistant PE-RT pipe manufacturing device of this embodiment includes a feeding and drying module, a plasticizing and extrusion module, a forming die module, a traction module, a cutting module, and a collection module connected in sequence. After the forming die module and before the traction module, multiple sizing-temperature regulation-stress relief modules are arranged in sequence along the pipe conveying direction. These modules include a first hot sizing section, a second slow cooling sizing section, a third uniform temperature stress relief section, and a fourth final cooling section.

[0038] The first hot sizing section includes a hot sizing box, which contains a vacuum sizing chamber and is regulated by a first temperature control loop. In this embodiment, the first temperature control loop consists of a circulating pump, a heat exchanger, and a mixing valve. The control module can achieve closed-loop temperature control of the hot sizing box by adjusting the opening of the mixing valve and the speed of the circulating pump.

[0039] The second slow cooling and sizing section includes a slow cooling and sizing box, which is equipped with an independent vacuum degree adjustment loop and temperature regulation through a second temperature control loop. The second temperature control loop can also be composed of a circulating pump, a heat exchanger, and a mixing valve to achieve closed-loop temperature control of the slow cooling and sizing box.

[0040] In this embodiment, the second slow cooling sizing section is divided into at least two slow cooling temperature zones (the first slow cooling temperature zone and the second slow cooling temperature zone) along the conveying direction. Each slow cooling temperature zone is equipped with an independent temperature acquisition point and an independent temperature control actuator to form a segmented slow cooling temperature drop curve.

[0041] The third temperature equalization and stress relief section is equipped with a temperature equalization and stress relief channel and its temperature control actuator. The temperature equalization and stress relief channel can be any one or a combination of a hot air channel, an infrared heating channel, or a circulating liquid temperature equalization channel; this embodiment takes a hot air channel as an example, and a controllable heating unit and an air volume adjustment unit are set in the channel to achieve adjustable channel temperature and heat exchange intensity. The control module links the equivalent residence time of the temperature equalization and stress relief section with the traction speed to ensure stable reproduction of the short-term temperature equalization and stress relief effect under continuous traction conditions.

[0042] The fourth final cooling section consists of a final cooling water tank and its temperature control actuator, used to reduce the pipe temperature to the allowable range for traction cutting.

[0043] This embodiment also includes an online detection module and a control module: the online detection module includes at least an outer diameter and ellipticity detection unit, a wall thickness detection unit, a first temperature detection unit, a second temperature detection unit, a traction tension detection unit, and a vacuum degree detection unit.

[0044] The system includes: a first temperature detection unit located at the outlet of the first hot sizing section to detect the surface temperature T1 of the pipe; a second temperature detection unit located at the outlet of the second slow cooling sizing section to detect the surface temperature T2 of the pipe; a traction tension detection unit located at the guide and tension detection position of the traction module and whose traction tension Ft is obtained by converting the torque of the traction motor; and a vacuum detection unit used to detect the sizing vacuum Pv.

[0045] In an optional implementation, the online detection module may further include a cooling medium temperature detection unit and a flow detection unit, which the control module uses as feedback or feedforward quantities for the temperature control of the second slow cooling sizing section, so as to reduce the temperature control lag caused by environmental fluctuations.

[0046] The control module is connected to the above-mentioned online detection module, the second temperature control loop, the third temperature control actuator for the stress relief section, the vacuum adjustment loop for the first hot sizing section, and the drive actuator signal of the traction module. It is used to calculate the residual stress characterization index S according to the core formula and execute the coordinated control logic of "stress priority and size constraint".

[0047] This embodiment normalizes and integrates key state variables related to residual stress formation during cooling and traction processes, constructs a residual stress characterization index S as the main control variable, and upgrades the control objective from "only size meets the standard" to "stress state is controllable and size is constrained", thereby suppressing the hidden risk of size compliance but excessive residual stress fluctuation.

[0048] The control module executes the following calculation process in each control cycle (0.5s to 2s, preferably 1s):

[0049] Collect online detection values: acquire T1, T2, traction speed v, traction tension Ft, sizing vacuum degree Pv, and simultaneously acquire dimensional detection values ​​such as outer diameter / ellipticity and wall thickness.

[0050] Calculate the temperature gradient term and the cooling rate term:

[0051] Temperature gradient characterization quantity: ;

[0052] Temperature range time parameters: , where L is the axial distance between the first temperature detection position and the second temperature detection position, which is measured and fixed as a system parameter during equipment installation;

[0053] Cooling rate characterization quantity: .

[0054] Calculate S using the formula:

[0055]

[0056] in A positive normalization constant is preset to eliminate the influence of dimensions and make the contributions of each component comparable; These are preset weighting coefficients used to reflect the relative sensitivity of different process factors to residual stress risk.

[0057] Through the above calculations, S reflects the comprehensive level of "temperature gradient and cooling rate (thermal history), traction tension (mechanical input), and vacuum constraint (geometric constraint)" under the current operating conditions. The larger S is, the higher the risk of residual stress or the greater the fluctuation. Based on this, the control module controls S within a preset stress window, while simultaneously constraining the outer diameter, ellipticity, and wall thickness within a preset size window.

[0058] This embodiment employs a coordinated control logic of "stress priority, size constraint" and sets a traction speed change rate limit strategy to avoid introducing secondary stress input and control oscillations during traction adjustment. Its control strategy can be summarized into the following rules, and each rule provides an implementable operational method:

[0059] Stress-priority adjustment (main loop): When the control module determines that S exceeds the preset stress window upper limit (e.g., S>Smax), it prioritizes the coordinated temperature adjustment of the second slow cooling sizing section and the third isothermal stress relief section to reduce stress. Combined with R, it enhances the stress relief effect at uniform temperature:

[0060] First, increase the temperature control setting value of the second slow cooling sizing section (or increase the setting value of the first slow cooling temperature zone and decrease the temperature drop in the second slow cooling temperature zone) to make the temperature drop curve smoother, thereby reducing R and lowering ;

[0061] If S is still higher than the window after one or more control cycles, increase the temperature control setting value of the third temperature equalization and stress relief section or enhance the heat exchange intensity of the channel (increase the air volume or heating power) to enhance the short-term temperature equalization and stress relief.

[0062] When the aforementioned temperature adjustment has reached the allowable upper limit or the effect is still insufficient, the control module reduces the traction speed setpoint while meeting the rate of change limitation strategy, in order to increase... This reduces R and the risk of stress peak.

[0063] In an alternative implementation, if it is necessary to further reduce the contribution of vacuum constraint to residual stress, the control module can appropriately reduce |Pv| within the limits of the size window constraint to reduce the stress concentration tendency caused by strong constraint.

[0064] Size constraint adjustment (from loop): When S is within the stress window (e.g., Smin≤S≤Smax) but there are deviations in outer diameter / ovallinity or wall thickness, the control module further eliminates the size deviation by adjusting the vacuum setting value and / or traction speed setting value of the first hot sizing section.

[0065] For deviations in outer diameter / ovality, prioritize fine-tuning the vacuum level and sizing constraint strength of the first hot sizing section;

[0066] For wall thickness deviations, adjust the traction speed or execution parameters related to extrusion stability in a coordinated manner without disrupting the stress window.

[0067] Traction speed change rate limiting strategy: In order to suppress the secondary stress input caused by traction adjustment, the control module applies a change rate limit to the traction speed setpoint, so that the change in traction speed within any control cycle does not exceed a preset threshold (not exceeding 0.5% to 2% of the rated speed, or not exceeding a certain fixed speed increment), so as to ensure control stability and reduce oscillation.

[0068] Through the aforementioned master-slave coordinated control, the device can use S as the master control variable to perform closed-loop constraints on temperature range and stress state under production fluctuations or environmental disturbances, and complete the coordinated adjustment of vacuum and traction under size window constraints, realizing a closed-loop control link of structure-parameter-algorithm coupling.

[0069] This embodiment provides a simplified calibration procedure that can be implemented in engineering to determine and This allows for the creation of traceable parameter configurations.

[0070] Baseline operation and data acquisition

[0071] After the equipment is installed and commissioned, select several typical specifications (e.g., different combinations of outer diameter and wall thickness) of PE-RT pipes for baseline production. The control mode adopts a size window closed loop (outer diameter / ovalness, wall thickness meet the standards) and keeps the process parameters stable within the allowable range.

[0072] Collect data continuously for no less than N control cycles (e.g., N≥3000), and record it. The dimensions such as R, Ft, |Pv|, as well as outer diameter / ovality, wall thickness, etc., are verified offline to check the dimensional changes or temperature and pressure resistance of the finished product after thermal cycling.

[0073] Determination of the normalization constant ( )

[0074] The collected data were statistically analyzed, and the following were taken respectively. Representative scales of R, Ft, and |Pv| are used as normalization constants. A certain proportion of their mean, quantile (such as P90 or P95), or allowable upper limit under stable operating conditions is taken to ensure that the magnitudes of all parameters are comparable after normalization and sensitive to abnormal fluctuations. This step forms a set of initial normalization constants and embeds them into the control module parameter table.

[0075] Determination of weighting coefficients ( )

[0076] Small-scale orthogonal experiments or stepped disturbance experiments were conducted to combine and vary the setpoints for the second slow cooling zone, the third uniform temperature, the traction speed, and the vacuum degree, within the allowable range of the equipment, obtaining multiple sets of samples. Changes in ellipticity after thermal cycling, wall thickness fluctuations, temperature and pressure resistance retention, or scrap rate were used as external evaluation indicators. Linear regression, least squares fitting, or sensitivity analysis methods were employed to determine... The relative contributions of R, Ft, and |Pv| to external evaluation indicators; then, the contributions are normalized into weight coefficients to obtain the initial... .

[0077] To ensure the stability of S as a comprehensive index, the weighting coefficients can be set to non-negative and normalized (so that their sum is 1), and minor adjustments can be made within a preset range in subsequent production.

[0078] Determining the stress window (Smin, Smax)

[0079] The calibrated parameters are applied to trial production, the S distribution corresponding to qualified samples is statistically analyzed, and stress windows are set in combination with external evaluation indicators. For example, the S corresponding to the change in ellipticity, wall thickness fluctuation and temperature and pressure resistance after thermal cycling meet the enterprise standards or preset thresholds falls within the window, thereby determining Smin and Smax.

[0080] The above calibration process enables S to have traceable parameter sources and reproducible engineering configuration logic, providing a consistent basis for subsequent batch switching or specification switching.

[0081] To illustrate the effect of introducing the S-control system, this embodiment provides a set of exemplary comparative diameters. For the same specification PE-RT pipe, two control modes are used under the same raw material and equipment conditions:

[0082] Mode A: Closed-loop dimensional control is performed only on the outer diameter / ovality and wall thickness;

[0083] Mode B: Under the constraint of the size window, S-control is introduced to adjust the temperature in conjunction with slow cooling and uniform temperature stress relief according to the above rules, and adjust the vacuum degree / traction speed in coordination when necessary and apply the traction change rate limit.

[0084] Comparative evaluation criteria may include:

[0085] 1) Rate of change of ellipticity after thermal cycling (e.g., the change of ellipticity measured after testing under enterprise standard thermal cycling conditions).

[0086] 2) Production scrap rate (statistics based on online scrap judgment and offline re-inspection);

[0087] 3) Wall thickness fluctuation (e.g., standard deviation of wall thickness or peak-to-peak value);

[0088] 4) Temperature and pressure holding (e.g., the pass rate within a specified temperature and pressure holding time).

[0089] In a set of exemplary pilot productions, Mode B, compared to Mode A, exhibits the following characteristics: reduced ellipticity change rate after thermal cycling, lower scrap rate, convergence of wall thickness fluctuations, and an increased proportion of products meeting temperature and pressure resistance standards. The above comparison illustrates that by incorporating temperature gradient, cooling rate, traction tension, and vacuum constraint into the same control framework, the S-controller can suppress residual stress-related fluctuations while achieving dimensional compliance, thus improving stability under high-temperature conditions. Specific values ​​can be recorded and written into the example data table based on different pipe diameters, raw material batches, and enterprise standards.

[0090] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0091] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-temperature resistant PE-RT pipe manufacturing apparatus, comprising a feeding and drying module, a plasticizing and extrusion module, a forming die head module, a traction module, a cutting module, and a collecting module connected in sequence, characterized in that, It also includes a multi-section sizing-temperature regulation-stress relief module, an online detection module, and a control module arranged sequentially along the pipe conveying direction; The multi-segment sizing-temperature regulation-stress relief module sequentially includes a first hot sizing section, a second slow cooling sizing section, a third temperature equalization and stress relief section, and a fourth final cooling section, wherein: The first hot sizing section includes a hot sizing box with a vacuum sizing cavity and a first temperature control circuit connected to the hot sizing box. The second slow cooling and sizing section includes a slow cooling and sizing box with an independent vacuum degree adjustment circuit and a second temperature control circuit connected to the slow cooling and sizing box; The third temperature equalization and stress relief section includes the temperature equalization and stress relief channel and its temperature control actuator; The fourth final cooling section includes the final cooling water tank and its temperature control actuator; The online detection module includes at least: an outer diameter and ellipticity detection unit, a wall thickness detection unit, a first temperature detection unit, a second temperature detection unit, a traction tension detection unit, and a vacuum detection unit. The first temperature detection unit is located at the outlet of the first hot sizing section to detect the surface temperature T1 of the pipe, and the second temperature detection unit is located at the outlet of the second slow cooling sizing section to detect the surface temperature T2 of the pipe. The control module is connected to the online detection module, the second temperature control loop, the third temperature-relieving stress section temperature control actuator, the first hot sizing section vacuum adjustment loop, and the traction module drive actuator signal, and is configured to: calculate the residual stress characterization index S based on the online detection value, and use S as the main control quantity to perform linkage temperature adjustment on the second slow cooling sizing section and the third temperature-relieving stress section, while simultaneously adjusting the vacuum degree and / or traction speed of the first hot sizing section in a coordinated manner under the constraints that the outer diameter, ellipticity, and wall thickness are within a preset size window; The residual stress characterization index S is calculated according to the following formula: In the formula: ; ; L is the axial distance between the first temperature detection position and the second temperature detection position; For traction speed; This is the measured value of traction tension; This is the measured value of vacuum degree during sizing; This is a pre-defined positive normalization constant; These are preset weighting coefficients.

2. The high-temperature resistant PE-RT pipe manufacturing apparatus according to claim 1, characterized in that, The first temperature control loop and the second temperature control loop each include a circulating pump, a heat exchanger, and a mixing valve. The control module achieves closed-loop temperature control of the corresponding segment by adjusting the opening degree of the mixing valve and the speed of the circulating pump.

3. The high-temperature resistant PE-RT pipe manufacturing apparatus according to claim 1, characterized in that, The second slow cooling sizing section is divided into at least two slow cooling temperature zones arranged sequentially along the conveying direction. Each slow cooling temperature zone has an independent temperature acquisition point and an independent temperature control actuator to form a segmented slow cooling temperature drop curve.

4. The high-temperature resistant PE-RT pipe manufacturing apparatus according to claim 1, characterized in that, The third temperature-equalizing stress relief section has a temperature-equalizing stress relief channel that is any one or a combination of a hot air channel, an infrared heating channel, or a circulating fluid temperature-equalizing channel. The control module links the equivalent residence time of the temperature-equalizing stress relief section with the traction speed to achieve short-term temperature-equalizing stress relief under continuous traction conditions.

5. The high-temperature resistant PE-RT pipe manufacturing apparatus according to claim 1, characterized in that, The online detection module also includes a cooling medium temperature detection unit and a flow detection unit. The control module uses the cooling medium temperature and flow rate as feedback or feedforward quantities for the temperature control of the second slow cooling sizing section to reduce temperature control lag caused by environmental fluctuations.

6. The high-temperature resistant PE-RT pipe manufacturing apparatus according to claim 1, characterized in that, The control module is equipped with a traction speed change rate limiting strategy to ensure that the change in the traction speed setpoint within any control cycle does not exceed a preset threshold, thereby suppressing secondary stress input and control oscillations caused by traction adjustment.

7. The high-temperature resistant PE-RT pipe manufacturing apparatus according to claim 1, characterized in that, The control module adopts a coordinated control logic of "stress priority and size constraint": when S exceeds the preset stress window, the temperature control setting value of the second slow cooling sizing section and the temperature control setting value of the third uniform temperature stress relief section are adjusted first to bring S back into the window; when there are still deviations in outer diameter, ellipticity or wall thickness within the stress window, the size deviation is eliminated by adjusting the vacuum setting value of the first hot sizing section and the traction speed setting value.

8. A method for manufacturing a high-temperature resistant PE-RT pipe, characterized in that, The high-temperature resistant PE-RT pipe manufacturing apparatus according to any one of claims 1 to 7 includes: plasticizing and extruding PE-RT raw material and forming a pipe blank through a forming die; and then traction, cutting and collecting the pipe blank after it passes through a first hot sizing section, a second slow cooling sizing section, a third uniform temperature stress relief section and a fourth final cooling section in sequence. During the manufacturing process, outer diameter / ellipticity, wall thickness, T1, T2, Ft, Pv and traction speed v are collected, and S is calculated according to the core formula described in claim 1. Based on S, the second slow cooling sizing section and the third uniform temperature stress relief section are linked for temperature adjustment, and the vacuum degree and traction speed of the first hot sizing section are coordinated under the constraint of the size window.

9. The method for manufacturing high-temperature resistant PE-RT pipe according to claim 8, characterized in that, When S exceeds the preset stress window, the control module triggers at least one handling strategy: increasing the temperature control setting value of the second slow cooling sizing section to reduce the temperature drop rate R and reduce ΔT, and increasing the temperature control setting value of the third uniform temperature stress relief section to enhance the uniform temperature stress relief effect.

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