Polyethylene pipe thermal oxidation aging test device under high sulfur gas field water action

Abstract

This invention relates to the technical field of pipe performance testing equipment, and discloses a thermo-oxidative aging testing device for polyethylene pipes under the action of high-sulfur gas field water. The device includes a testing machine and a docking mechanism located inside the testing machine. This docking mechanism seals and fixes both ends of the pipe under test and forms a passage for the circulation of corrosive media. A replacement mechanism, also located inside the testing machine, includes a base plate and a sand storage chamber on the base plate. The sand storage chamber is used to lay sand and gravel. A pressure mechanism is located at the top of the testing machine. A liquid storage tank and a centrifugal pump are connected to the outside of the docking mechanism for circulating high-sulfur gas field water into the pipe under test. By subjecting the inner wall of the pipe to corrosive liquid erosion and the outer wall to thermo-oxidative aging, the device simulates the pipe's usage under combined corrosion and aging conditions, making the test results more consistent with actual engineering applications.

Description

Technical Field

[0001] This invention relates to the technical field of pipe performance testing equipment, specifically a thermo-oxidative aging testing device for polyethylene pipes under the action of high-sulfur gas field water. Background Technology

[0002] Polyethylene (PE) pipes are widely used in oil and gas field gathering and transportation systems due to their excellent corrosion resistance, flexibility, and ease of processing, especially for transporting media such as gas field water. In actual service, some gas field water contains salts, acidic components, and other corrosive media. The inner wall of the PE pipe is subjected to long-term erosion, penetration, and chemical corrosion by these media. Simultaneously, the outer wall of buried pipes is also affected by ground temperature, soil conditions, and oxygen diffusion, leading to thermo-oxidative aging. The long-term coupled effect of internal media erosion and external thermo-oxidative aging results in a decline in the mechanical properties and structural integrity of the PE pipe, ultimately affecting its service life and operational reliability.

[0003] To assess the service life and reliability of polyethylene pipes, thermo-oxidative aging tests are typically conducted before they are put into actual use. However, existing pipe aging testing equipment lacks realistic simulation of the combined conditions of internal wall corrosion and external thermo-oxidative aging. Existing aging testing devices often only perform tests under a single environment, such as simply placing the pipe in a high-temperature aging chamber for thermo-oxidative aging, or only conducting internal fluid pressurization tests. In actual use environments, pipes are in a coupled state of continuous scouring and erosion of the internal wall by corrosive liquids and external thermo-oxidative aging. A single aging test cannot realistically reproduce this combined internal and external condition, resulting in a significant deviation between the aging data obtained from the test and the actual aging evolution process of the pipe during underground use, making it impossible to accurately predict its true service life. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water, which solves the problem that existing pipe aging test equipment lacks realistic simulation of the combined working conditions of internal wall corrosion and external wall thermo-oxidative aging.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water, comprising a test machine and a docking mechanism disposed inside the test machine for sealing and fixing both ends of the pipe to be tested and forming a passage for the circulation of corrosive medium, wherein the corrosive medium is high-sulfur gas field water; a replacement mechanism disposed inside the test machine, comprising a base plate and a stone storage chamber disposed on the base plate, wherein the stone storage chamber is used to lay sand and gravel; a pressure mechanism disposed at the top of the test machine; and a liquid storage tank and a centrifugal pump connected to the outside of the docking mechanism for circulating high-sulfur gas field water into the pipe to be tested.

[0006] Preferably, the docking mechanism includes a bottom ring, the outer side of which is disposed on the inner wall of the testing machine, an outer tube is fixedly connected to the outer side of the bottom ring, an external threaded ring is threadedly connected to the inner side of the outer tube, and a swivel ring is fixedly connected to the outer side of the external threaded ring.

[0007] Preferably, the docking mechanism further includes a locking plate, one end of which is fixed to the outside of the bottom ring, and the other end of which abuts against the conical end of the external threaded ring.

[0008] Preferably, the replacement mechanism further includes a central shaft, the outer side of which is fixedly connected to the inside of the base plate, and a buckle is rotatably connected to the outer side of the central shaft. A locking slot is provided at the bottom end of the stone storage bin.

[0009] Preferably, the pressure mechanism includes a partition plate, the outer side of which is fixedly connected to the inside of the testing machine, an electric cylinder is installed inside the partition plate, a spherical hinge is fixedly connected to the output end of the electric cylinder, and a pressure plate is fixedly connected to the bottom end of the spherical hinge.

[0010] Preferably, the pressure mechanism further includes a side pressure assembly, which includes an airbag embedded in the sand and gravel, and an air pump connected to the airbag via an air pipe, the air pump being located inside the testing machine.

[0011] Preferably, the side pressure component works in conjunction with the pressure plate to simulate the triaxial stress state of the pipe under test in an actual buried environment.

[0012] Preferably, the docking mechanism further includes a pipe, one end of which is connected to the bottom ring, and the other end is connected to the liquid storage tank and the centrifugal pump respectively, to form a passage for the corrosive medium to circulate inside the tube to be tested.

[0013] Preferably, the centrifugal pump is located inside the testing machine, and the air pump is located inside the testing machine.

[0014] The corrosive medium leaked from the aged and ruptured test tube falls directly into the stone storage bin, and the replacement is completed by removing the stone storage bin.

[0015] This invention provides a thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water. It has the following beneficial effects: 1. This invention uses the cooperation between the outer tube and the rotating ring to drive the external threaded ring to advance axially. Its conical surface drives the locking plate to radially contract and tighten the tube under test, forming a sealed passage. Then, a centrifugal pump drives high-sulfur gas field water to continuously circulate inside the tube under test. At the same time, the testing machine provides a high-temperature environment, so that the inner wall of the tube under test is subjected to corrosive liquid erosion and the outer wall is subjected to thermo-oxidative aging. This simulates the use state of the pipeline under the combined conditions of corrosion and aging, making the test results more consistent with the actual engineering application scenario.

[0016] 2. This invention uses a base plate to support a drawer-type stone storage bin. Pulling the buckle upwards causes it to rotate around the central axis, which in turn releases the lock from the stone storage bin. When the test tube breaks due to long-term testing, or when high-sulfur gas field water leaks and contaminates the sand and gravel inside, the operator can directly pull out the drawer-type stone storage bin and quickly replace the contaminated sand and gravel. This avoids the presence of corrosive media inside the testing machine and prevents it from interfering with subsequent tests.

[0017] 3. This invention uses a partition plate to fix an electric cylinder, which drives a pressure plate to move downward. The vertical pressure is evenly transmitted to the outer surface of the pipe under test using sand and gravel, simulating the soil pressure and traffic dynamic load above the buried pipeline. At the same time, an air pump inflates an airbag buried in the sand and gravel through an air pipe, which drives the application of lateral confining pressure. This works in conjunction with the vertical pressure to realistically reproduce the three-dimensional stress environment of the soil on the pipeline and avoid local stress concentration. Attached Figure Description

[0018] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the reverse side structure of the testing machine of the present invention; Figure 3 This is a front view of the testing machine of the present invention; Figure 4 This is a diagram of the internal structure of the testing machine of the present invention; Figure 5 This is a schematic diagram of the docking mechanism of the present invention; Figure 6 This is a schematic diagram of the internal structure of the docking mechanism of the present invention; Figure 7 This is a cross-sectional view of the docking mechanism of the present invention; Figure 8 This is a schematic diagram of the replacement mechanism of the present invention.

[0019] The components include: 1. Testing machine; 2. Test tube; 3. Sand and gravel. 4. Connecting mechanism; 41. Outer tube; 42. Swivel ring; 43. External threaded ring; 44. Bottom ring; 45. Locking plate; 46. Pipeline; 47. Liquid storage tank; 48. Centrifugal pump; 5. Replacement mechanism; 51. Base plate; 52. Stone storage bin; 53. Fastener block; 54. Central shaft; 55. Clamping joint; 6. Pressure mechanism; 61. Baffle plate; 62. Electric cylinder; 63. Spherical hinge; 64. Pressure plate; 65. Side pressure assembly; 651. Airbag; 652. Air pipe; 653. Air pump. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see the appendix Figure 1 - Appendix Figure 4This invention provides a thermo-oxidative aging test device for polyethylene pipes under the action of water in high-sulfur gas fields. The device includes a test machine 1, which provides a closed and controllable test environment for the entire aging test, simulating the complex working conditions of high temperature and corrosion coupling in high-sulfur gas fields. This avoids external environmental interference and ensures the authenticity and reliability of the test data. The test machine 1 has a built-in heating component, allowing for temperature adjustment. The temperature adjustment range covers the actual temperature range from the gas field surface to different depths underground, replicating the real temperature conditions of the gas field. The thermo-oxidative aging test device also includes a docking mechanism 4, a replacement mechanism 5, and a pressure mechanism 6. The docking mechanism 4 is located inside the test machine 1 and is used to seal and fix both ends of the pipe 2 under test, connecting the pipe 2 to the circulation path and forming a closed-loop path for the corrosive medium to circulate. This ensures that the corrosive medium acts on the inner wall of the pipe 2 under test, recreating the media scouring and corrosion scenario in actual use. The docking mechanism 4 achieves sealing and fixing of both ends of the pipe 2 under test through the coordinated action of multiple components, preventing leakage of corrosive media and ensuring the continuity of media circulation. Continuing, the replacement mechanism 5 is located inside the testing machine 1, including a base plate 51 and a stone storage bin 52 mounted on the base plate 51. The base plate 51 provides stable bottom support and smooth sliding guidance for the stone storage bin 52, ensuring convenient pulling out. The testing machine 1 is equipped with a guide rail, on which the stone storage bin 52 slides, limiting its movement trajectory and preventing deviation during pulling out. The stone storage bin 52 is used to lay sand and gravel 3, which simulates the soil medium in the buried environment of polyethylene pipes, serving as the test pipe 2. It provides support to avoid uneven local stress affecting the test results, and can also transmit pressure load to make the stress act evenly on the outer wall of the test tube 2. The gradation of the sand and gravel 3 is consistent with the actual buried soil of the gas field, with uniform particle size to ensure uniform pressure transmission. At the same time, it has a certain degree of air permeability to restore the actual characteristics of the soil. The pressure mechanism 6 is set at the top inside the test machine 1. The outside of the docking mechanism 4 is connected to the liquid storage tank 47 and the centrifugal pump 48, which are used to circulate and transport high sulfur gas field water into the test tube 2. The corrosive medium is high sulfur gas field water.

[0022] Please see the appendix Figure 2 - Appendix Figure 4The pressure mechanism 6 is located at the top inside the testing machine 1. It is used to simulate the stress state of the test pipe 2 under actual buried environment, such as the soil pressure and traffic dynamic load, to improve the accuracy of the working condition simulation and make the test results more consistent with the actual application scenario. The pressure mechanism 6 can realize the coordinated loading of vertical pressure and lateral confining pressure. The loading parameters can be flexibly adjusted according to the soil characteristics of different gas fields and the burial depth of the test pipe 2. The outside of the docking mechanism 4 is connected to the liquid storage tank 47 and the centrifugal pump 48. The liquid storage tank 47 is used to store high sulfur gas field water to avoid medium shortage or composition change during the test. The liquid storage tank 47 can store a sufficient amount of high sulfur gas field water. The tank is equipped with A stirring device ensures uniform medium composition and a stable corrosive environment during testing. Centrifugal pump 48 provides power for the circulation of high-sulfur gas field water. The circulation speed can be adjusted to match the actual working conditions of different gas fields. Together, they are used to circulate and deliver high-sulfur gas field water into the test tube 2, ensuring that the inner wall of the test tube 2 is in a continuous and stable corrosive environment for a long time. Centrifugal pump 48 drives the high-sulfur gas field water to circulate in a closed loop. The circulation speed can be adjusted by a valve, covering the actual medium flow rate of the gas field, so that the medium continuously washes the inner wall of the test tube 2, restoring the real corrosion process. Centrifugal pump 48 is installed inside the testing machine 1.

[0023] Please see the appendix Figure 5 - Appendix Figure 7 The docking mechanism 4 includes a bottom ring 44, the outer side of which is set on the inner wall of the testing machine 1. It adopts a symmetrical installation layout, providing an installation base for the outer tube 41 and the locking plate 45, preventing component displacement that could lead to sealing failure. The bottom ring 44 is fixed to the inner wall of the testing machine 1 by bolts, ensuring a firm connection and defining the installation position of the outer tube 41 and the locking plate 45, ensuring consistent coaxiality of the docking structures on both sides. The outer tube 41 is fixedly connected to the outer side of the bottom ring 44, serving as the installation carrier and guide structure for the external threaded ring 43. Its inner wall is threaded, and the threaded engagement enables the smooth axial advancement of the external threaded ring 43. The high precision of the inner wall thread of the outer tube 41 ensures a tight meshing with the thread of the external threaded ring 43, guaranteeing a smooth and uninterrupted advancement process and providing good sealing. The internal thread of the outer tube 41 is connected to the external threaded ring 43, which will guide the rotational movement. Stability is converted into axial thrust, driving the locking plate 45 to contract uniformly. One end of the external threaded ring 43 has a conical surface with an optimized angle, which can uniformly squeeze the locking plate 45 during advancement, making the contraction amplitude of the locking plate 45 consistent. A rotating ring 42 is fixedly connected to the outside of the external threaded ring 43. Its outer circumference is provided with anti-slip texture, providing a force application point for the operator. By manually rotating and adjusting, rotating the rotating ring 42 can drive the external threaded ring 43 to move axially along the outer tube 41. The anti-slip texture increases the friction between the hand and the rotating ring 42, making it easier for the operator to apply torque. The corrosive medium is high-sulfur gas field water, whose composition is consistent with the actual gas field produced water, replicating the internal wall corrosion environment of the test tube 2 in actual use. High-sulfur gas field water contains corrosive ions such as sulfides and chloride ions. The ion concentration matches that of the actual gas field water, ensuring that the corrosion intensity is consistent with the real working conditions.

[0024] Please see the appendix Figure 5 - Appendix Figure 6 The docking mechanism 4 also includes a locking plate 45. One end of the locking plate 45 is fixed to the outside of the bottom ring 44, and the other end of the locking plate 45 abuts against the conical end of the external threaded ring 43. The locking plate 45 adopts a multi-lobed symmetrical design. When the external threaded ring 43 is pushed in, the locking plate 45 is squeezed by the wedge action of the conical surface, causing the multi-lobed locking plate 45 to radially contract and firmly hold the outside of the tube to be tested 2, achieving integrated sealing and fixing. After the locking plate 45 contracts, it fits tightly against the outer wall of the tube to be tested 2. A sealing gasket is provided on the contact surface to enhance the sealing effect and prevent the medium from leaking from the gap. The docking mechanism 4 also includes a pipe 4. 6. One end of pipe 46 is connected to bottom ring 44, and the other end is connected to storage tank 47 and centrifugal pump 48 respectively, to form a passage for the corrosive medium to circulate inside the test tube 2. Pipe 46 is made of corrosion-resistant material. Pipe 46 connects bottom ring 44 to storage tank 47 and centrifugal pump 48 to form a medium circulation channel. The diameter of pipe 46 is adapted to the test tube 2 to ensure smooth medium flow without local stagnation. It is used to ensure the continuous and stable circulation of corrosive medium inside the test tube 2, to ensure uniform corrosion and avoid local corrosion from affecting the test results.

[0025] Please see the appendix Figure 8 The replacement mechanism 5 also includes a central shaft 54, the outer side of which is fixedly connected to the inside of the base plate 51, providing a fulcrum for the buckle block 53 to ensure smooth rotation. The central shaft 54 ​​is welded to the base plate 51, with its axis perpendicular to the surface of the base plate 51, defining the rotation center of the buckle block 53 and ensuring smooth rotation. The buckle block 53 is rotatably connected to the outer side of the central shaft 54, enabling quick locking and unlocking of the stone storage bin 52 through rotation. When the buckle block 53 rotates, it can engage or disengage from the latch 55. The engaging end of the buckle block 53 is provided with anti-slip teeth to enhance stability after engagement. The bottom end of the stone storage bin 52 has a latch 55 that matches the engaging end of the buckle block 53, ensuring the safety of the stone storage bin 52. Securely installed inside the testing machine 1, ensuring pressure transmission, the storage chamber 52 is fixed to the base plate 51 after the bayonet 55 and the buckle 53 engage, with no relative displacement, ensuring the stability of the sand and gravel 3 position during pressure loading. Corrosive media leaked after the test tube 2 ages and cracks fall directly into the storage chamber 52. The sand and gravel 3 can be replaced by pulling out the storage chamber 52. The storage chamber 52 receives the leaked media, preventing contamination of the inside of the testing machine 1. The replacement and cleaning of the sand and gravel 3 can be completed quickly by pulling out the storage chamber 52, shortening the test interruption time. The storage chamber 52 has a drawer-type structure, and the contaminated sand and gravel 3 can be poured out directly after being pulled out. The inner wall is smooth and easy to clean. After replacing with new sand and gravel 3, it can be reinstalled, making the operation highly efficient.

[0026] Please see the appendix Figure 3 - Appendix Figure 4The pressure mechanism 6 includes a partition 61, the outer side of which is fixedly connected to the inside of the testing machine 1, providing a stable mounting base and force support for the electric cylinder 62, ensuring stable pressure loading. The partition 61 is fixed to the cavity of the testing machine 1 by bolts, resulting in a strong structural rigidity, bearing the installation and working load of the electric cylinder 62 without deformation or displacement. The electric cylinder 62 is installed inside the partition 61, serving as a vertical pressure power source. By adjusting the output pressure, the pressure plate 64 acts on the sand and gravel 3. A spherical hinge 63 is fixedly connected to the output end of the electric cylinder 62, and the pressure plate 64 is fixedly connected to the bottom end of the spherical hinge 63. 4. The large-area flat plate design can evenly transmit the concentrated power of the electric cylinder 62 to the surface of the sand and gravel 3, so as to achieve uniform application of vertical pressure and avoid excessive local pressure. The pressure plate 64 acts on the central area of ​​the surface of the sand and gravel 3. Through the particle conduction of the sand and gravel 3, the pressure is evenly transmitted to the outer wall of the tube under test 2 with small pressure distribution deviation. The spherical hinge 63 enables multi-angle adaptive fine adjustment of the pressure plate 64 to ensure that the pressure plate 64 fits the surface of the sand and gravel 3 and improves the uniformity of pressure distribution. The spherical hinge 63 allows the pressure plate 64 to tilt slightly, which can compensate for the slight unevenness of the surface of the sand and gravel 3 and ensure that the pressure is evenly transmitted to the tube under test 2.

[0027] Please see the appendix Figure 2 - Appendix Figure 4 The pressure mechanism 6 also includes a side pressure assembly 65, which includes an airbag 651 embedded in the sand and gravel 3 and an air pump 653 connected to the airbag 651 via an air pipe 652. The airbag 651 is made of a flexible and corrosion-resistant material and can naturally deform according to the distribution of the sand and gravel 3. After inflation, it can uniformly apply lateral confining pressure to the surrounding area, simulating the lateral constraint of the soil on the test tube 2. The airbag 651 is embedded in the sand and gravel 3 and arranged around the circumference of the test tube 2. After inflation, it uniformly squeezes the sand and gravel 3 to form a uniform lateral confining pressure. The magnitude of the confining pressure can be controlled by the air pressure. The air pipe 652 adopts a high-pressure sealed pipeline to ensure no air pressure leakage. The air pipe 652 connects the air pump 653 and the airbag 651. Set inside the testing machine 1, the lateral pressure is adjusted according to different soil densities. The air pump 653 has air pressure regulation and pressure holding functions. The target air pressure can be set according to the test requirements, and it continuously provides stable air pressure to the airbag 651 to control the lateral confining pressure. The lateral pressure component 65 and the pressure plate 64 work together to simulate the triaxial stress state of the pipe under test 2 in the actual buried environment. The vertical pressure and lateral confining pressure are loaded together to reproduce the triaxial stress state of the pipe under test 2 after burial. The stress parameters can be monitored and adjusted in real time through the control terminal to ensure consistency with the actual working conditions, improve the reliability and reference value of the test results, and enable the test results to truly reflect the aging performance of the pipe under test 2 under the complex stress and corrosion coupling effect.

[0028] Working principle: Before the test starts, the test tube 2 is sealed and connected. The bottom ring 44 of the connection mechanism 4 is set on both sides of the inner wall of the testing machine 1. The outer tube 41 is fixed on the outer side of the bottom ring 44. The rotating ring 42 is sleeved on both ends of the test tube 2 and the two ends are aligned with the outer tube 41 and inserted until it contacts the pipe 46. The outer tube 41 is threadedly engaged with the external threaded ring 43. By rotating the rotating ring 42, the external threaded ring 43 can be driven to move inward along the axial direction of the outer tube 41. The end of the external threaded ring 43 that faces inward into the outer tube 41 is a conical surface. At this time, the external threaded ring 43 contacts the outer side of the locking plate 45, driving the locking plate 45 to contract radially along the conical surface of the inner wall of the outer tube 41, firmly gripping the outer side of the test tube 2, forming a sealed passage. The bottom ring 44 is used for The movement of the limiting locking plate 45 is designed to prevent excessive compression that could damage the test tube 2 or cause seal failure. Meanwhile, the two ends of the test tube 2 are connected to an external storage tank 47 and a centrifugal pump 48 via pipes 46. The storage tank 47 is pre-stored with high-sulfur gas field water. After the centrifugal pump 48 is started, it can drive the high-sulfur gas field water to flow continuously and stably inside the test tube 2, so that the inner wall of the tube is in a corrosive medium environment for a long time. At the same time, the test machine 1 provides a high-temperature environment to apply a thermo-oxidative aging load to the outer wall of the test tube 2, thereby realistically replicating the coupled aging state of corrosion of the inner wall and thermo-oxidative aging of the outer wall of the test tube 2. Compared with a single aging test, this is more in line with the actual use scenario of the test tube 2.

[0029] The replacement mechanism 5 uses the base plate 51 as the overall support foundation, and is equipped with a drawer-type stone storage bin 52. The stone storage bin 52 is filled with sand and gravel 3, which serves as the bottom support for the test tube 2 and cooperates with subsequent pressure loading. Pulling one end of the buckle block 53 upwards causes the buckle block 53 to rotate inside the base plate 51 with the central axis 54 as the axis. The other end of the buckle block 53 retracts into the base plate 51, so that the bayonet 55 is no longer restricted by the buckle block 53. When the test tube 2 ages and cracks due to the advancement of the test time, the high sulfur gas field water flowing inside will leak and contaminate the sand and gravel 3 in the stone storage bin 52. At this time, the drawer-type stone storage bin 52 can be directly pulled out and clean sand and gravel 3 can be replaced, effectively avoiding the residual corrosive media from the leak and preventing it from interfering with the subsequent tests inside the testing machine 1.

[0030] The partition 61 of the pressure mechanism 6 is fixed to the upper part of the working chamber of the testing machine 1. The electric cylinder 62 is installed inside the partition 61. The output end of the electric cylinder 62 is connected to the pressure plate 64 through the ball joint 63. After the electric cylinder 62 is started, it drives the pressure plate 64 to move downward. The pressure plate 64 acts on the sand and gravel 3 in the stone storage bin 52. The vertical pressure is evenly transmitted to the outer surface of the pipe under test 2 through the sand and gravel 3, thereby simulating the soil pressure and traffic dynamic load above the buried pipe under test 2. The ball joint 63 allows the pressure plate 64 to be slightly tilted in any direction to ensure that the vertical pressure is evenly loaded after contact with the sand and gravel 3, and to avoid local stress concentration in the pipe under test 2.

[0031] To better simulate soil pressure and further improve the accuracy of working condition simulation, an airbag 651 of the side pressure component 65 is specially buried in the sand and gravel 3. The air pump 653 inflates the airbag 651 through the air pipe 652. After inflation, the airbag 651 can apply controllable lateral confining pressure to the sand and gravel 3 outside the test tube 2. It works in conjunction with the vertical pressure applied by the pressure plate 64 to realize the true simulation of the triaxial stress on the buried test tube 2, and to restore the stress state of the test tube 2 in the actual buried environment to the greatest extent.

Claims

1. A thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water, comprising a test machine (1), characterized in that, Also includes: The docking mechanism (4) is located inside the test machine (1) and is used to seal and fix the two ends of the tube to be tested (2) and form a passage for the corrosive medium to circulate. The corrosive medium is high sulfur gas field water. The replacement mechanism (5) is located inside the test machine (1) and includes a base plate (51) and a stone storage bin (52) located on the base plate (51). The stone storage bin (52) is used to lay sand and gravel (3). The pressure mechanism (6) is located at the top inside the testing machine (1); The docking mechanism (4) is connected to a storage tank (47) and a centrifugal pump (48) on the outside, which are used to circulate and transport high-sulfur gas field water into the test tube (2).

2. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 1, characterized in that, The docking mechanism (4) includes a bottom ring (44), the outer side of which is disposed on the inner wall of the testing machine (1). An outer tube (41) is fixedly connected to the outer side of the bottom ring (44), and an external threaded ring (43) is threadedly connected to the inner side of the outer tube (41). A swivel ring (42) is fixedly connected to the outer side of the external threaded ring (43).

3. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 2, characterized in that, The docking mechanism (4) also includes a locking plate (45), one end of which is fixed to the outside of the bottom ring (44), and the other end of which abuts against the conical end of the external threaded ring (43).

4. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 1, characterized in that, The replacement mechanism (5) also includes a central shaft (54), the outer side of which is fixedly connected to the inside of the base plate (51), and a buckle (53) is rotatably connected to the outer side of the central shaft (54). A slot (55) is provided at the bottom end of the stone storage bin (52).

5. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 4, characterized in that, The pressure mechanism (6) includes a partition (61), the outer side of which is fixedly connected to the inside of the testing machine (1). An electric cylinder (62) is installed inside the partition (61), and a spherical hinge (63) is fixedly connected to the output end of the electric cylinder (62). A pressure plate (64) is fixedly connected to the bottom end of the spherical hinge (63).

6. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 5, characterized in that, The pressure mechanism (6) further includes a side pressure assembly (65), which includes an airbag (651) embedded in the sand (3) and an air pump (653) connected to the airbag (651) via an air pipe (652).

7. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 6, characterized in that, The side pressure component (65) works in conjunction with the pressure plate (64) to simulate the triaxial stress state of the tube under test (2) in the actual buried environment.

8. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 2, characterized in that, The docking mechanism (4) also includes a pipe (46), one end of which is connected to the bottom ring (44), and the other end is connected to the liquid storage tank (47) and the centrifugal pump (48) respectively, to form a passage for the corrosive medium to circulate inside the tube (2) to be tested.

9. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 6, characterized in that, The centrifugal pump (48) is located inside the test machine (1), and the air pump (653) is located inside the test machine (1).

10. The thermo-oxidative aging test device for polyethylene pipes under the action of high-sulfur gas field water according to claim 1, characterized in that, The corrosive medium leaked from the tested tube (2) after aging and cracking falls directly into the stone storage bin (52), and the replacement is completed by removing the stone storage bin (52).

Images