PEXA pipe hot aging test box

Abstract

The present application relates to the technical field of pipe material heat aging, in particular to a PEXA pipe material heat aging test box, which comprises a pull-out type frame body arranged in a test cavity, the pull-out type frame body comprises a rotating section, the rotating section is provided with a clamping piece and a bottom support piece; the conical table is rotated by 180 degrees, the dumbbell-shaped sample is clamped by the elastic clamp, at this time, the circular ring limits the movement range of the lower end of the dumbbell-shaped sample; the elastic clamp is rotated by 180 degrees, at this time, the inverted conical structure cooperates with the conical table to stably fix the straight pipe-shaped sample without stress, and the straight pipe-shaped sample is still through from top to bottom. The T-shaped plug-in high-stability locking, counterweight self-stability and double-position limiting mode are adopted, a multifunctional integrated clamping structure is formed, no clamping deformation of the sample in the heat aging test is realized, the sample is exposed to the maximum extent and anti-interference, and the core problems of stress concentration, uneven heat exchange and low position stability in the sample fixing mode in the traditional heat aging test are solved.

Description

Technical Field

[0001] This invention relates to the field of pipe thermal aging technology, specifically a PEXA pipe thermal aging test chamber. Background Technology

[0002] Thermal aging testing is a key method for evaluating the performance stability and service life of polymer materials (such as PEXA pipes) under long-term high-temperature environments. By simulating the thermal stress conditions that materials may experience in actual use, aging phenomena such as mechanical property degradation, color change, and surface cracking can be effectively detected.

[0003] In practice, the shapes of the test samples are mainly divided into two categories: one is dumbbell-shaped, used to evaluate the tensile strength and elongation at break of the material; the other is straight tube-shaped, used to evaluate the overall durability and structural stability of the tube in a thermo-oxidative environment. Existing thermal aging test chambers generally use a tray placement method or a single-end suspension clamping method to place the samples, and the test chamber is usually equipped with a forced air circulation system to ensure temperature uniformity.

[0004] When straight tubular samples are placed on a tray, horizontal placement may cause deformation due to their own weight during the test. At the same time, airflow impact may cause the straight tubular samples to shift or even rotate on the tray, thereby affecting the positional stability of the samples, causing surface deformation, and affecting the test results. When a single-end suspension clamping method is used, the end of the straight tubular sample will deform due to the clamping force, which may cause local stress concentration at high temperatures. In addition, the end of the straight tubular sample will also be closed due to clamping, which will hinder the flow of hot air in the inner cavity of the straight tubular sample. This will lead to inconsistent aging rates between the inner and outer walls of the straight tubular sample, making it difficult to truly reflect the aging behavior of the material in actual applications.

[0005] When dumbbell-shaped samples are placed on a tray, uneven thermal aging may occur on both sides. There is also the possibility of displacement or overturning due to airflow impact. When a single-end suspension clamping method is used, some devices will also introduce a rotation function to further improve the uniformity of heat exchange. When airflow and centrifugal force work together, or when the airflow speed and centrifugal force are large, the dumbbell-shaped samples may swing because they are thin, have low gravity, and are in a suspended state. This may cause collisions or contact between samples, especially when there are many samples. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a PEXA pipe thermal aging test chamber, configured with a test chamber; including a pull-out frame housed within the test chamber, the pull-out frame comprising a rotating section, on which clamping components and a base support are provided; the clamping components include: a hanging body, circumferentially equidistantly distributed, including T-shaped columns and a rectangular frame disposed below it; elastic clamps, each elastic clamp corresponding to a hanging body and rotatably mounted within the rectangular frame; and counterweight balls, symmetrically and rotatably mounted outside the elastic clamps to maintain their verticality; the rotating section has T-shaped grooves that mate with the T-shaped columns, the outer side of the T-shaped grooves being open; the base support includes: a component disposed on... The rotating section has a truncated cone located below the elastic clamp, corresponding to it one by one and extending vertically. Upper insert plates are symmetrically positioned inside the non-clamping end of the elastic clamp, with spacing between them forming a conical structure. A ring is positioned below the large-diameter end of the truncated cone. A counterweight is symmetrically and rotatably mounted on the outside of the truncated cone to keep it vertical. When the truncated cone rotates 180 degrees, the elastic clamp suspends and holds the dumbbell-shaped sample; at this time, the ring limits the lower end's range of motion. When the elastic clamp rotates 180 degrees, the conical structure is inverted and engages with the truncated cone to fix the straight tube sample without stress; the straight tube sample remains vertically continuous.

[0007] Preferably, both the sidewall of the truncated cone and the sidewall of the upper insert plate are provided with evenly distributed ventilation holes.

[0008] Preferably, the opening width on the outside of the T-slot is equal to the diameter of the vertical section of the T-column. After the vertical section of the T-column enters the T-slot through the opening, it automatically moves downward under the action of gravity, and the horizontal section of the T-column is inserted into the horizontal section of the T-slot. At this time, the horizontal degree of freedom of the T-column is limited.

[0009] Preferably, when the conical structure is inverted and mates with the frustum to define the position of the straight tube sample, the small-diameter ends of the conical structure and the frustum are respectively inserted into the two ends of the straight tube sample, and the straight tube sample is fully defined, but the conical structure does not apply a compressive force to the straight tube sample.

[0010] Preferably, the inner diameter of the ring is larger than the size of the lower end of the dumbbell-shaped sample; while the rotating section drives the dumbbell-shaped sample to rotate through the clamping member and delivers air into the test chamber, the ring limits the range of motion of the lower end of the dumbbell-shaped sample, and at this time the lower end of the dumbbell-shaped sample does not contact the end face of the cone.

[0011] Preferably, grid plates are provided at both ends and the bottom of the test chamber. During the thermal aging test, air is delivered into the test chamber from three directions, and the air from top to bottom passes through the straight tube sample.

[0012] Preferably, the counterweight ball is mounted on the outside of the non-clamping end of the elastic clamp via a pull rope, and the axis of rotation of the pull rope is parallel to the axis of rotation of the elastic clamp.

[0013] Preferably, the PEXA pipe thermal aging test chamber is also equipped with a rotary drive; the pull-out frame is controlled by a locking device to connect with the rotary drive, and after connection, the rotary drive drives the rotating section of the pull-out frame to rotate.

[0014] Preferably, the locking element includes guide rails that are symmetrically and fixedly installed in the test chamber, and the pull-out frame also includes a fixed section that is linearly slidably connected to the guide rails. Under the limit of the guide rails, the pull-out frame moves stably and horizontally into and out of the test chamber. When the pull-out frame is outside the test chamber, the sample placement operation is performed.

[0015] Preferably, the clamping components and the base support are positioned away from the grid plates on the left and right sides and the inner wall of the rear side of the test chamber.

[0016] The beneficial effects of this invention are:

[0017] I. The T-type plug-in high-stability locking, counterweight self-stabilization, and dual-position limiting mode adopted in this invention form a multi-functional integrated clamping structure, which realizes the sample without clamping deformation, maximum exposure and anti-interference in the thermal aging test, and solves the core problems of stress concentration, uneven heat exchange and low position stability in the traditional sample fixing method in the thermal aging test.

[0018] Second, the same set of clamping structures of the present invention has two sample position limiting modes. The two sample limiting modes only require flipping the corresponding parts by 180 degrees, and can automatically return to vertical position after flipping without additional manual or mechanical structure correction, thus ensuring the placement state of the sample. Specifically, the position limiting of dumbbell-shaped samples adopts a suspension clamping + non-contact dynamic limiting method, while the position limiting of straight tube-shaped samples adopts a stress-free double-end insertion and fixing + ensuring vertical continuity. This ensures that the sample is effectively fixed and not deformed by additional forces, while also maximizing the exposure of the sample and helping the sample maintain its original physical properties without being affected.

[0019] Third, the present invention uses an elastic clamp to suspend and hold the upper end of the dumbbell-shaped sample, while the lower end of the dumbbell-shaped sample hangs freely to avoid stress concentration. At the same time, a dynamic circumferential protective structure is formed by the ring, which allows the dumbbell-shaped sample to swing slightly but avoids collision, and allows airflow to surround the dumbbell-shaped sample to ensure uniform thermal aging.

[0020] Fourth, this invention uses a combination of a frustum and an inverted cone structure to naturally insert the sample into the end of the straight tube without compressing it, thus achieving non-compression positioning, avoiding local stress concentration, and maintaining the original shape of the straight tube sample. At the same time, the frustum is connected vertically and vertically, and the upper insert plates are symmetrically arranged at certain intervals, so that the straight tube sample remains connected vertically, avoiding the formation of local thermal resistance, promoting air circulation inside the straight tube sample, and causing the inner and outer walls of the straight tube sample to age synchronously.

[0021] Fifth, the T-shaped column and T-shaped groove in this invention have dual locking capabilities of lateral tensile strength and longitudinal shear strength. Compared with the weak connection of traditional fine hook hanging holes that rely solely on top suspension, it can more firmly fix the clamping assembly on the rotating section without the need for additional bolt tightening or tools. Even when the airflow speed and centrifugal force are high, the clamping parts and the base support parts cannot move, ensuring the structural stability of the entire clamping system and thus avoiding the instability of the clamping structure from exacerbating the instability of the sample state. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of the clamping component, the base support component, the locking component, and the rotation drive component in this invention.

[0024] Figure 3 This is a schematic diagram of the clamping component and the pull-out frame in this invention.

[0025] Figure 4 This is a schematic diagram of the clamping component and T-slot in this invention.

[0026] Figure 5 This is a schematic diagram of the structure of the base support and locking component in this invention.

[0027] Figure 6 This is a schematic diagram of the structure of the base support component in this invention.

[0028] Figure 7 This is a schematic diagram of the structure of the dumbbell-shaped sample defined by the elastic clamp and the ring in this invention.

[0029] Figure 8 This is a schematic diagram of the structure of the upper insert plate and the truncated cone used in this invention to define a straight tube-shaped sample.

[0030] In the diagram: 1. Pull-out frame; 2. Clamping component; 3. Base support component; 4. Grid plate; 5. Rotation drive component; 6. Locking component; 10. Rotating section; 100. T-slot; 11. Fixed section; 20. Hanger; 21. Elastic clamp; 22. Counterweight ball; 200. T-shaped column; 201. Rectangular frame; 30. Frustum; 31. Upper insert plate; 32. Ring; 33. Counterweight bar; 60. Guide rail; 61. Push bar; 62. Extension plate; 63. Arc plate. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described below, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Please see Figure 1 and Figure 2 A PEXA pipe thermal aging test chamber is provided, equipped with a heating system, an air circulation system, a control and monitoring system, and a test chamber. These components are all existing technologies, and their specific structures will not be described in detail in this invention. In addition, the test chamber is also equipped with a rotary drive component 5 and a pull-out frame 1. The rotary drive component 5 includes a drive shaft that is rotatably mounted on the bottom wall of the test chamber. The drive shaft is fixedly connected to the output shaft of a built-in motor (not shown in the figure), and a rectangular block is slidably mounted on the upper end of the drive shaft. Grid plates 4 are provided at the left, right, and lower ends of the test chamber. During the thermal aging test, air is supplied into the test chamber from three directions, and the drive shaft rotates through the corresponding grid plates 4.

[0033] Please see Figure 1 , Figure 2 and Figure 3 The pull-out frame 1 includes a rotating section 10, which consists of a vertical cylinder and a ring segment fixed to the outer side of the upper end of the cylinder by several support rods. The ring segment is coaxial with the cylinder. A rectangular groove is provided on the lower end face of the cylinder to connect with a rectangular block. The cylinder is controlled by a locking member 6 to connect with a rotation drive member 5. After connection, the rotating section 10 of the pull-out frame 1 is driven to rotate by the rotation drive member 5. The rotating section 10 is provided with a clamping member 2 and a bottom support member 3. The clamping member 2 and the bottom support member 3 are both set away from the grid plates 4 on the left and right sides and the inner wall of the rear side of the test chamber.

[0034] Please see Figure 3 , Figure 4 , Figure 7 and Figure 8 The clamping component 2 includes an elastic clamp 21 and a counterweight ball 22. The elastic clamp 21 is circumferentially equidistant and rotatably arranged. The clamping end of the elastic clamp 21 is rounded, and the rotation axis of the elastic clamp 21 extends radially along the cylinder. The counterweight ball 22 is symmetrically arranged and is rotatably installed on the outside of the non-clamping end of the elastic clamp 21 by a pull rope. The rotation axis of the pull rope is parallel to the rotation axis of the elastic clamp 21. The counterweight ball 22 is used to keep the elastic clamp 21 vertical.

[0035] Please see Figure 4 , Figure 5 , Figure 6 and Figure 7The base support 3 includes a truncated cone 30, an upper insert plate 31, a ring 32, and a counterweight 33. The truncated cone 30 is located below the elastic clamp 21 and corresponds one-to-one with the elastic clamp 21. The truncated cone 30 is vertically continuous and is fixedly installed at the end of the sleeve. The sleeve is rotatably installed at one end of the fixing rod, and the other end of the fixing rod is fixedly connected to the outer ring wall of the same ring seat. The ring seat is fixed to the rotating section 10 by bolts, which are symmetrically arranged on both sides of the rotating section 10, with at least two bolts. The upper insert plate 31 is symmetrically arranged inside the non-clamping end of the elastic clamp 21, and the symmetrical upper insert plates 31 form a conical structure. However, it should be noted that the distance between the symmetrical upper insert plates 31 is sufficient to pinch the elastic clamp 21 to open the clamping end of the elastic clamp 21, so as to complete the operation of clamping dumbbell-shaped samples. The ring 32 is fixedly connected to the lower end face of the large-diameter end of the truncated cone 30 by a connecting rib. The counterweight 33 is symmetrically and rotatably mounted on the outside of the truncated cone 30. The counterweight 33 is used to keep the truncated cone 30 vertical. Figure 6 As shown, the counterweight 33 is rotatably mounted on one end of the pin, and the other end of the pin is fixedly connected to the outer wall of the truncated cone 30, with the pin located at the end of the counterweight 33. Uniformly distributed ventilation holes are provided on both the outer wall of the truncated cone 30 and the upper insert plate 31, thereby increasing the contact area between air and the inner wall of the straight tube sample while ensuring the stability of the straight tube sample's position.

[0036] Please see Figure 2 and Figure 6 In addition, the rotating section 10 has mounting holes (not shown in the figure) that are evenly distributed from top to bottom and are used to mate with bolts. The position of the ring seat can be adjusted by matering the bolts with the mounting holes at different heights, thereby adjusting the distance between the clamping member 2 and the bottom support member 3 to meet the needs of accommodating samples of different lengths.

[0037] Please see Figures 1 to 8 The specific working process is as follows: Before the test, the sample is placed at 23±2℃ and 50±5% humidity for at least 24 hours, and the initial properties of the sample (such as tensile strength, elongation at break, etc.) are measured. The sample color and surface condition are photographed and recorded as baseline data. Before placing the sample, the test chamber needs to be preheated to the target temperature to reduce temperature fluctuations. After the test chamber is preheated to the target temperature, the chamber door is opened. The operator, with the help of tools or wearing heat-resistant gloves, first disconnects the connection between the pull-out frame 1 and the rotary drive 5 through the locking piece 6, and then moves the pull-out frame 1 outward. Finally, the pull-out frame 1 is located outside the test chamber. The purpose of the pull-out design is to avoid placing the sample in a limited space, improve the convenience and efficiency of sample placement, and also help ensure the consistency of sample placement.

[0038] Then, select the appropriate placement and fixing method according to the shape of the sample. When the sample is dumbbell-shaped (e.g.) Figure 7As shown), first rotate the truncated cone 30 180 degrees. The inverted truncated cone 30 will remain vertical under the action of the counterweight 33. At this time, the ring 32 is located above the inverted truncated cone 30. Then, the upper end of the dumbbell-shaped sample is clamped and fixed by the clamping end of the elastic clamp 21 (at this time, the clamping end of the elastic clamp 21 is naturally facing downwards). Then, lift the elastic clamp 21 slightly upwards so that the lower end of the dumbbell-shaped sample is located inside the ring 32. Then, release the elastic clamp 21. The elastic clamp 21 will automatically move down and reset under the action of gravity. However, it should be noted that at this time, the dumbbell-shaped sample does not contact the truncated cone 30 and the ring 32 (the inner diameter of the ring 32 is much larger than the size of the lower end of the dumbbell-shaped sample), ensuring that the airflow flows around the dumbbell-shaped sample; the ring 32 is used to limit the range of motion of the lower end of the dumbbell-shaped sample. During the subsequent rotation of the clamping part 2 driven by the cylinder and the three-way input of air into the test chamber, the ring 32 forms a circumferential protective structure to prevent the dumbbell-shaped sample from contacting the side wall of the test chamber under the action of centrifugal force and gas blowing.

[0039] When the sample is a straight tube type (e.g.) Figure 8 As shown), first rotate the elastic clamp 21 180 degrees. The elastic clamp 21 will remain vertical under the action of the counterweight ball 22. At this time, the conical structure is inverted and directly opposite the truncated cone 30. Then, first lift the elastic clamp 21 upwards and place the straight tube sample on the truncated cone 30 (at this time, the truncated cone 30 is naturally upright). The small diameter end of the truncated cone 30 is naturally inserted into the end of the straight tube sample, achieving the purpose of both limiting and not applying stress. The end of the straight tube sample does not deform or only deforms slightly. Then, move the elastic clamp 21 downwards so that the small diameter end of the inverted conical structure is also naturally inserted into the end of the straight tube sample, but the conical structure does not... Applying clamping force to the straight tubular sample and fixing it through a non-compression conical insertion method ensures that the straight tubular sample does not undergo axial deformation and remains vertically continuous, while also helping to maintain the original physical properties of the straight tubular sample without affecting them. This avoids the deformation of the straight tubular sample caused by traditional clamping, which would affect the accuracy of the aging data. Furthermore, because the truncated cone 30 is vertically continuous, there is a gap between the two upper insert plates 31 that make up the conical structure, and air vents are provided on both the upper insert plates 31 and the truncated cone 30, the straight tubular sample, even in a position-limited state, remains vertically continuous, allowing air to pass through it, resulting in uniform thermal aging inside and outside the straight tubular sample.

[0040] Switching between the two fixed sample modes requires only a 180-degree flip, while the automatic reset function of the counterweight ball 22 and counterweight bar 33 ensures that no manual angle calibration is needed after operation, transforming complex attitude control into a simple physical self-balancing mechanism. Furthermore, the design of the two fixed sample modes ensures that all types of samples can undergo thermal aging tests with maximum area exposure, thereby improving the accuracy and reliability of the test results.

[0041] It should be noted that even if samples are fixed between several clamping parts 2 and base support parts 3, there is still an effective distance between the circumferentially distributed samples, rather than they are arranged closely together; when placing samples, the cylinder can be driven by the operator to rotate the clamping parts 2 and base support parts 3 as a whole to place samples circumferentially.

[0042] Please see Figure 2 , Figure 3 and Figure 5 The locking component 6 includes a guide rail 60 symmetrically and fixedly installed on the bottom wall of the test chamber, and a push bar 61 linearly slidably connected to the guide rail 60. The pull-out frame 1 also includes a fixed section 11 linearly slidably connected to the guide rail 60 via a long bar. The fixed section 11 is an inverted U-shaped plate, and the long bar is fixedly installed at the lower end of the vertical section of the inverted U-shaped plate. The long bar is horizontally set, and under the limit of the guide rail 60, the pull-out frame 1 stably and horizontally enters and exits the test chamber. The end of the push bar 61 near the rear side wall of the test chamber has a wedge-shaped structure. The moving areas of the push bar 61 and the corresponding long bar are independent of each other and will not interfere with each other's movement. On opposite sides of the rail 60, upper push plates that mate with the inclined surfaces of the wedge-shaped structure are slidably installed vertically. Extended plates 62, which contact the upper surfaces of the corresponding upper push plates, are symmetrically installed at both ends of the rectangular block. Simultaneously, arc-shaped plates 63 are symmetrically arranged on the front and rear sides of the rectangular block. The lower ends of the arc-shaped plates 63 are fixedly connected to the corresponding grid plates 4 via fixed posts. The distance between two arc-shaped plates 63 is slightly greater than the width of the extended plates 62. To improve the structural strength of the upper push plates, guide posts are slidably installed between the lower side of the upper push plate near the rectangular block and the bottom wall of the test chamber. The guide posts slide through the corresponding grid plates 4. Furthermore, several through holes are provided on the horizontal section of the fixed section 11, the upper push plates, and the extended plates 62 to reduce obstruction of airflow from bottom to top.

[0043] After the sample is placed, the pull-out frame 1 is pushed into the test chamber. The long strip moves to the end point and cannot be moved any further. At this point, the cylinder is directly above the rectangular block. Then, the operator pushes the push bar 61 inward. The wedge-shaped inclined surface of the push bar 61 moves the upper push plate upward. The upper push plate then pushes the rectangular block upward through the extension plate 62 until the upper end of the rectangular block is fully inserted into the rectangular groove. At this point, the upper surface of the upper push plate is flush with the upper surface of the arc plate 63, and the opposite ends of the two upper push plates and the two arc plates 63 form a complete annular support surface. Then, the chamber door is closed, and the thermal aging test begins and the start time is recorded. During the test, the built-in motor controls the drive shaft, rectangular block, and cylinder to rotate together. The cylinder drives the clamping part 2, the bottom support part 3, and the fixed sample to rotate together, enhancing the heat exchange uniformity of the sample surface. The extension plate 62 rotates along the annular support surface, and the annular support surface continuously and effectively supports and limits the extension plate 62. The rotation speed, wind speed, and temperature are automatically monitored and controlled in real time according to the experimental requirements. The total test time is preset. After the set time is reached, the test chamber is closed, the sample is taken out, and the sample is cooled at 23℃ for 1-2 hours. Then, the color change and surface condition are observed and photographed. Subsequently, tensile strength, elongation at break and other tests are performed and the data are recorded. The data before and after heat aging are compared to obtain the heat aging results.

[0044] It should be noted that after the push bar 61 moves inward into place, its position can be limited by conventional structures such as pins, and then the door can be closed. At the same time, the inner wall of the door abuts against the end of the push bar 61 and the end of the long strip. Alternatively, the extension plate 62 can be rotated slightly with the rectangular block by rotating the drive component 5. The extension plate 62 moves onto the arc plate 63 without contacting the upper push plate. At this time, the upper push plate stays at its current position, and then the door can be closed. The position of the push bar 61 is limited by the inner wall of the door abutting against the end of the push bar 61 and the end of the long strip. The specific setting method can be selected according to the actual situation.

[0045] Please see Figure 3 , Figure 4 , Figure 7 and Figure 8The clamping component 2 also includes circumferentially equidistant hanging bodies 20. Each hanging body 20 includes a T-shaped post 200, a U-shaped mounting plate, and a rectangular frame 201. The rectangular frame 201 is fixedly mounted on one end of the U-shaped mounting plate, and the other end of the U-shaped mounting plate is fixedly connected to the lower end of the vertical section of the T-shaped post 200. The rectangular frame 201 is located directly below the T-shaped post 200. A T-shaped groove 100 is formed on the annular section of the rotating section 10 to mate with the T-shaped post 200. The T-shaped groove 100 extends vertically. The outer side of the T-slot 100 (i.e. the side away from the axis of the rotating section 10) is open, and the opening width of the outer side of the T-slot 100 is equal to the diameter of the vertical section of the T-post 200. After the T-post 200 and the T-slot 100 are inserted and matched, they maintain a stable position. The elastic clip 21 corresponds to the hanging body 20 one by one and is rotatably installed in the rectangular frame 201. The internal space of the rectangular frame 201 and the distance between the rectangular frame 201 and the lower end face of the vertical section of the T-post 200 are sufficient for the elastic clip 21 to rotate.

[0046] When the sample is dumbbell-shaped, the operator needs to squeeze the effective position of the elastic clamp 21 to open the clamping end of the elastic clamp 21. This increases the operator's operating space requirements, and the time required to fix dumbbell-shaped samples is longer compared to fixing the same number of straight tube-shaped samples. Therefore, to facilitate operator operation, shorten the opening time of the chamber door when placing samples, and reduce heat loss and temperature fluctuations, the elastic clamp 21 can be used to clamp the dumbbell-shaped samples outside the test chamber beforehand. In this case, the operator's operating space is basically unaffected, which is beneficial for quickly and efficiently clamping and fixing dumbbell-shaped samples. After fixing, open the box door and pull out the pull-out frame 1. Then, first flip the truncated cone 30, and then let the vertical section of the T-shaped column 200 fit into the vertical section of the T-shaped groove 100. At this time, the lower end of the dumbbell-shaped sample is basically aligned with the middle of the ring 32. Then, just release the handle. The T-shaped column 200, rectangular frame 201 and other components will automatically move down under the action of gravity. Finally, the horizontal section of the T-shaped column 200 fits into the horizontal section of the T-shaped groove 100. After the T-shaped column 200 and the T-shaped groove 100 are inserted and engaged, they maintain a stable position. At this time, the T-shaped column 200 cannot be moved horizontally out of the T-shaped groove 100. The lower end of the dumbbell-shaped sample is located inside the ring 32. Compared to the traditional method that requires aligning a slender hook with a small hanging hole to suspend the clamp and sample, which is time-consuming and prone to misalignment, the wide inlet guide design of the T-slot 100 allows the T-post 200 to enter quickly. After the horizontal section of the T-post 200 is inserted into the T-slot 100, it is naturally locked by gravity, forming a tensile and shear-resistant mechanical lock. Even if rotated at a high speed, it will not come out. The elastic clamp 21 will not cause the sample to move in multiple directions with a large amplitude. At the same time, the structure is simple but highly reliable, easy to use and durable.

[0047] It should be noted that all components placed inside the test chamber are made of high-temperature resistant, low-thermal-conductivity, and non-stick materials, or have their surfaces coated with a high-temperature resistant, low-thermal-conductivity, and non-stick coating to avoid metal catalytic effects. The clamping end of the elastic clamp 21, the outer wall of the upper insert plate 31, and the outer wall of the truncated cone 30 can be provided with a high-temperature resistant, low-thermal-conductivity, and non-stick elastic silicone layer, which is both anti-slip and prevents indentation.

[0048] This invention does not simply solve two separate problems: dumbbell-shaped fixation and straight-tube fixation. Instead, it addresses the common problem of "systematic defects in sample fixation methods during thermal aging tests" by proposing a unified and optimized solution. Its innovations lie in: structural reusability, allowing the same component to be adapted to two types of samples; and core consistency, ensuring stress-free operation, maximum exposure, and high stability.

[0049] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integral connection, or a sliding connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made based on the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A PEXA pipe thermal aging test chamber, equipped with a test chamber; characterized in that, It includes a pull-out frame installed inside the test chamber, the pull-out frame including a rotating section, and clamping parts and a base support on the rotating section; The clamping components include: The hanging body is circumferentially distributed and includes T-shaped columns and rectangular frames set on their lower sides; The elastic clips correspond one-to-one with the hanging body and are rotatably installed within the rectangular frame. A counterweight ball, symmetrically and rotatably mounted on the outside of the elastic clamp, is used to keep the elastic clamp vertical; The rotating section is provided with a T-shaped groove that mates with the T-shaped column, and the outer side of the T-shaped groove is open; The base support includes: The truncated cones set on the rotating section are located below the elastic clamps and correspond one-to-one with them and are connected vertically. The upper insert plates are symmetrically arranged inside the non-clamping end of the elastic clamp, and there is a gap between the symmetrical upper insert plates to form a conical structure; the gap forms an operating space for pinching the elastic clamp to open its clamping end; A circular ring is positioned on the lower side of the major diameter end of the frustum of cones. The counterweight bars are symmetrically and rotatably mounted on the outside of the truncated cone to keep the truncated cone vertical; The truncated cone rotates 180 degrees, and the elastic clamp suspends and holds the dumbbell-shaped sample. At this time, the ring limits the range of motion of the lower end of the dumbbell-shaped sample. The elastic clamp rotates 180 degrees. At this time, the conical structure is inverted and cooperates with the truncated cone to fix the straight tube sample without stress. The straight tube sample is still connected from top to bottom.

2. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: Both the sidewalls of the truncated cone and the sidewalls of the upper insert plate are provided with evenly distributed ventilation holes.

3. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: The opening width on the outside of the T-slot is equal to the diameter of the vertical section of the T-column. After the vertical section of the T-column enters the T-slot through the opening, it automatically moves downward under the action of gravity. The horizontal section of the T-column is inserted into the horizontal section of the T-slot, at which point the horizontal degree of freedom of the T-column is limited.

4. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: When the conical structure is inverted and mates with the frustum to define the position of the straight tube sample, the small-diameter ends of the conical structure and the frustum are respectively inserted into the two ends of the straight tube sample, and the straight tube sample is fully defined, but the conical structure does not apply a compressive force to the straight tube sample.

5. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: The inner diameter of the ring is larger than the size of the lower end of the dumbbell-shaped sample. During the rotation of the dumbbell-shaped sample by the rotating section through the clamping device and the supply of air into the test chamber, the ring limits the range of motion of the lower end of the dumbbell-shaped sample, and at this time the lower end of the dumbbell-shaped sample does not contact the end face of the cone.

6. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: The test chamber is equipped with grid plates at both ends and the bottom. During the thermal aging test, air is delivered into the test chamber from three directions, and the air from top to bottom passes through the straight tube sample.

7. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: The counterweight ball is mounted on the outside of the non-clamping end of the elastic clamp via a pull rope, and the axis of rotation of the pull rope is parallel to the axis of rotation of the elastic clamp.

8. The PEXA pipe thermal aging test chamber according to claim 1, characterized in that: The PEXA pipe thermal aging test chamber is also equipped with a rotary drive; the pull-out frame is controlled by a locking device to connect with the rotary drive, and after connection, the rotary drive drives the rotating section of the pull-out frame to rotate.

9. A PEXA pipe thermal aging test chamber according to claim 7, characterized in that: The locking mechanism includes symmetrically and fixedly installed guide rails inside the test chamber. The pull-out frame also includes a fixed section that is linearly slidably connected to the guide rails. Under the limit of the guide rails, the pull-out frame moves stably and horizontally into and out of the test chamber. When the pull-out frame is outside the test chamber, the sample placement operation is performed.

10. A PEXA pipe thermal aging test chamber according to claim 1, characterized in that: The clamping components and the base support are both positioned away from the grid plates on the left and right sides and the inner wall of the rear side of the test chamber.

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