Strength performance testing tool for vacuum insulation pipeline

Abstract

The invention relates to the field of vacuum heat insulation pipeline strength detection, in particular to a vacuum heat insulation pipeline strength performance testing tool which comprises a workbench, an air cylinder located on the surface of the workbench, a driving mechanism and an air pump. One end of an output shaft of the driving motor is fixedly connected with a fluted disc, the surface of the workbench is fixedly connected with a coating detection mechanism used for pipeline external pressure detection, and the surface of the coating detection mechanism is provided with an adjusting mechanism used for coping with pipelines with different diameters. According to the sealing structure, linear motion is converted into radial sealing and supporting actions through a connecting rod and a slope mechanism, automatic centering and efficient high-pressure sealing in the pipeline are achieved, the sealing structure is even in unfolding, damage to the inner wall of the pipeline is small, small inner diameter tolerance can be effectively compensated, and the sealing effect is good. And the absolute reliability of sealing in a subsequent high-pressure test is ensured.

Description

Technical Field

[0001] This invention relates to the field of strength testing of vacuum insulated pipes, specifically to a testing fixture for the strength performance of vacuum insulated pipes. Background Technology

[0002] Vacuum-insulated pipelines, due to their excellent thermal insulation properties, are widely used in systems transporting cryogenic media such as liquefied natural gas, liquid nitrogen, and liquid oxygen. The structural strength and sealing performance of these pipelines are core indicators of their safe operation, directly affecting the safety, efficiency, and environmental risks of the transported media. Therefore, before leaving the factory or during their service life, vacuum-insulated pipelines must undergo rigorous testing for external pressure strength, internal pressure strength, and airtightness.

[0003] Currently, strength and sealing tests on pipelines typically employ separate equipment and procedures. For external pressure strength testing, a common method is to apply radial pressure to the outside of the pipeline. However, traditional fixtures often use single-point pressure application or non-uniform clamping, which can easily lead to localized stress concentration in the pipeline, causing undue plastic deformation or distorted test data, and failing to accurately simulate the uniform external load borne by the pipeline under conditions such as vacuum interlayer failure. For internal pressure strength and airtightness testing, hydrostatic testing or separate pneumatic testing are commonly used. Hydrostatic testing suffers from problems such as cumbersome procedures, the need for post-test pipeline drying, and the potential for water pollution, making it particularly unsuitable for vacuum-insulated pipelines with high cleanliness requirements. Existing pneumatic testing fixtures often use end-face sealing or simple O-ring radial sealing methods, which suffer from insufficient sealing reliability, high dependence on the quality of pipeline end-face machining, and difficulty in adapting to slight deviations in the inner diameter of different pipelines. More importantly, internal pressure testing and airtightness testing are often two separate steps that require the use of different equipment or multiple clamping operations. This not only increases the complexity of the operation and reduces the efficiency of the test, but also introduces human error due to multiple clamping operations, affecting the consistency and accuracy of the test results. Summary of the Invention

[0004] The purpose of this invention is to provide a testing fixture for the strength performance of vacuum insulated pipes, thereby solving the problems mentioned in the background art. To achieve the above objective, this invention provides the following technical solution: A testing fixture for the strength performance of vacuum insulated pipes, comprising a worktable, a cylinder, a drive mechanism, and an air pump located on the surface of the worktable. The drive mechanism includes a drive motor, which is fixedly connected to the surface of the worktable. One end of the output shaft of the drive motor is fixedly connected to a gear plate. A coating detection mechanism for detecting the external pressure of the pipe is fixedly connected to the surface of the worktable. The surface of the coating detection mechanism is provided with an adjustment mechanism for accommodating pipes of different diameters. An internal pressure detection mechanism for detecting the internal strength of the pipe is installed on the surface of the worktable.

[0005] Preferably, the coating detection mechanism includes an annular fixed frame, which is fixedly connected to the surface of the worktable. A toothed plate is slidably connected to the inner circumference of the annular fixed frame, one of which is fixedly connected to the cylinder output shaft. A gear is rotatably connected to the inner circumference of the annular fixed frame, and the gears are circumferentially distributed inside the annular fixed frame and correspond to all the racks. Every two gears are connected by a universal joint to ensure the synchronicity of gear rotation. The lower end of the toothed plate is fixedly connected to two rotatable outer pressure plates.

[0006] Preferably, the adjustment mechanism includes a limiting slide rail, which is fixedly connected to the surface of the annular fixed frame and is circumferentially set on the surface of the annular fixed frame. An L-shaped support plate is slidably connected to the surface of the limiting slide rail, and a slide rod is slidably connected inside the limiting slide rail. A slot is fixedly connected to the lower end of the slide rod, and an L-shaped connecting rod is slidably connected inside the slot. The lower end of the L-shaped connecting rod is fixedly connected to the rotating shafts on both sides of the outer pressure plate.

[0007] Preferably, a retaining ring is fixedly connected to the surface of the L-shaped support plate, a spring telescopic rod is rotatably connected inside the L-shaped support plate, a retaining tooth is fixedly connected to the surface of the telescopic end of the spring telescopic rod, a handle is fixedly connected to one side of the telescopic end of the spring telescopic rod, an eccentric wheel is fixedly connected to the fixed end of the spring telescopic rod, a second groove is fixedly connected to the upper end of the slide rod, the outer shaft of the eccentric wheel is slidably connected inside the second groove, and a pin is fixedly connected to the center of the eccentric wheel. In the initial state, the pin is stuck inside the back of the toothed plate.

[0008] Preferably, the internal pressure detection mechanism includes a support rod, the entire internal pressure detection mechanism is set at the center of the covering detection mechanism, the support rod is fixedly connected to the surface of the workbench, a conical sealing ring is fixedly connected to the surface of the support rod, a toothed rod is rotatably connected to the back of the support rod, the toothed rod meshes with a toothed disc, a threaded groove is slidably connected to the surface of the support rod through an extended sliding frame, the threaded groove passes through the conical sealing ring, a connecting rod is circumferentially hinged to the surface of the threaded groove, and an internal pressure plate is hinged to the surface of the connecting rod.

[0009] Preferably, one end of the toothed rod is fixedly connected to a screw, which is threaded inside the threaded groove. One end of the sliding frame extending from the surface of the support rod is fixedly connected to a support plate. A folding slide groove is fixedly connected to the circumference of the surface of the support plate via a torsion spring. A limiting slide rod is slidably connected inside the folding slide groove. One end of the limiting slide rod is fixedly connected to an inner pressure plate. An inclined block is fixedly connected to the surface of the limiting slide rod, which functions to compress the folding slide groove and unfold it. The other end of the limiting slide rod is fixedly connected to an arc-shaped groove. All the arc-shaped grooves can form a ring. A solid sealing ring is embedded inside the arc-shaped groove. When the arc-shaped groove unfolds through the limiting slide rod, it can drive the solid sealing ring to open and seal one end of the steel pipe.

[0010] Preferably, the air pump is connected to the gear and screw via an air pipe.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, linear motion is converted into radial sealing and supporting actions through a connecting rod and inclined plane mechanism, achieving automatic centering and efficient high-pressure sealing inside the pipeline. This sealing structure unfolds uniformly, causes minimal damage to the pipeline's inner wall, and effectively compensates for small inner diameter tolerances, ensuring absolute reliability of the seal during subsequent high-pressure testing.

[0012] In this invention, uniform pressure application effectively avoids test data distortion or localized plastic deformation of the pipeline caused by stress concentration, providing a reliable data basis for accurately evaluating the external pressure resistance and structural stability of pipeline materials. After maintaining constant pressure for a certain period of time, observe whether there are any signs of instability or damage to the pipeline.

[0013] This invention enables stepless, precise, and self-locking adjustment of the covering contour, allowing a single tooling set to quickly and accurately adapt to a series of pipes with different diameters. This greatly improves the versatility of the equipment and the efficiency of test preparation, avoiding the cost and time consumption of configuring special molds for different pipe diameters. Attached Figure Description

[0014] Figure 1 This is a three-dimensional appearance diagram of the present invention; Figure 2 This is a schematic diagram of the side structure of the present invention; Figure 3 This is a schematic diagram of the coating detection mechanism of the present invention; Figure 4 This is a side cross-sectional view of the coating detection mechanism of the present invention; Figure 5 This is a partially enlarged structural diagram of the coating detection mechanism of the present invention; Figure 6 This is a schematic diagram of the adjusting mechanism structure of the present invention. Figure 1 ; Figure 7 This is a schematic diagram of the adjusting mechanism structure of the present invention. Figure 2 ; Figure 8 This is an enlarged schematic diagram of the retaining ring structure of the present invention; Figure 9 This is a partially enlarged schematic diagram of the adjustment mechanism of the present invention; Figure 10 This is a schematic diagram of the surface structure of the worktable of the present invention; Figure 11 This is a schematic diagram of the internal pressure detection mechanism of the present invention; Figure 12This is a side cross-sectional view of the internal pressure detection mechanism of the present invention; Figure 13 This is an enlarged schematic diagram of the inner pressure plate structure of the present invention; Figure 14 This is a partially enlarged schematic diagram of the internal pressure detection mechanism of the present invention. Figure 1 ; Figure 15 This is a partially enlarged schematic diagram of the internal pressure detection mechanism of the present invention. Figure 2 .

[0015] In the diagram: 1. Workbench; 2. Cylinder; 3. Drive mechanism; 31. Drive motor; 32. Gear plate; 4. Air pump; 5. Coating detection mechanism; 6. Adjustment mechanism; 7. Internal pressure detection mechanism; 51. Annular fixing frame; 52. Gear plate; 53. Gear; 54. Universal joint; 55. External pressure plate; 61. Limit slide rail; 62. L-shaped support plate; 63. Slide rod; 64. Groove one; 65. L-shaped connecting rod; 66. Locking pin. 67. Ring; 68. Spring telescopic rod; 69. Clamping tooth; 60. Handle; 610. Eccentric wheel; 611. Groove II; 612. Pin; 71. Support rod; 72. Conical sealing ring; 73. Toothed rod; 74. Threaded groove; 75. Connecting rod; 76. Inner pressure plate; 77. Screw; 78. Support plate; 79. Folding slide; 710. Limiting slide rod; 711. Inclined block; 712. Arc-shaped groove; 713. Solid sealing ring. Detailed Implementation

[0016] The technical solutions of 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 a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Please refer to... Figures 1 to 15The present invention provides a technical solution: a vacuum insulated pipe strength performance testing fixture, including a workbench 1, a cylinder 2, a drive mechanism 3, and an air pump 4 located on the surface of the workbench 1. The drive mechanism 3 includes a drive motor 31, which is fixedly connected to the surface of the workbench 1. One end of the output shaft of the drive motor 31 is fixedly connected to a gear plate 32. A covering detection mechanism 5 for detecting the external pressure of the pipe is fixedly connected to the surface of the workbench 1. An adjustment mechanism 6 for accommodating pipes of different diameters is provided on the surface of the covering detection mechanism 5. An internal pressure detection mechanism 7 for detecting the internal strength of the pipe is installed on the surface of the workbench 1. Preferably, the coating detection mechanism 5 includes an annular fixed frame 51, which is fixedly connected to the surface of the workbench 1. A toothed plate 52 is slidably connected to the inner circumference of the annular fixed frame 51. One of the toothed plates 52 is fixedly connected to the output shaft of the cylinder 2. A gear 53 is rotatably connected inside the annular fixed frame 51. The gears 53 are circumferentially distributed inside the annular fixed frame 51 and correspond to all the racks 52. Every two gears 53 are connected by a universal joint 54 to ensure the synchronicity of the rotation of the gears 53. The lower end of the toothed plate 52 is fixedly connected to two rotatable outer pressure plates 55. Preferably, the adjusting mechanism 6 includes a limiting slide rail 61, which is fixedly connected to the surface of the annular fixing frame 51 and is circumferentially set on the surface of the annular fixing frame 51. An L-shaped support plate 62 is slidably connected to the surface of the limiting slide rail 61, and a slide rod 63 is slidably connected inside the limiting slide rail 61. A slot 64 is fixedly connected to the lower end of the slide rod 63, and an L-shaped connecting rod 65 is slidably connected inside the slot 64. The lower end of the L-shaped connecting rod 65 is fixedly connected to the rotating shafts on both sides of the outer pressure plate 55. Preferably, a retaining ring 66 is fixedly connected to the surface of the L-shaped support plate 62, and a spring telescopic rod 67 is rotatably connected inside the L-shaped support plate 62. A retaining tooth 68 is fixedly connected to the surface of the telescopic end of the spring telescopic rod 67, and a handle 69 is fixedly connected to one side of the telescopic end of the spring telescopic rod 67. An eccentric wheel 610 is fixedly connected to the fixed end of the spring telescopic rod 67, and a slot 611 is fixedly connected to the upper end of the slide rod 63. The outer shaft of the eccentric wheel 610 is slidably connected inside the slot 611, and a pin 612 is fixedly connected to the center of the eccentric wheel 610. In the initial state, the pin 612 is stuck inside the back of the toothed plate 52. The pin 612 fixed to the center of the eccentric wheel 610 is also stuck into the corresponding hole on the back of the toothed plate 52, forming a double lock, which ensures the positional stability of the outer pressure plate 55 in the subsequent testing process.Preferably, the internal pressure detection mechanism 7 includes a support rod 71. The entire internal pressure detection mechanism 7 is located at the center of the covering detection mechanism 5. The support rod 71 is fixedly connected to the surface of the workbench 1. A conical sealing ring 72 is fixedly connected to the surface of the support rod 71. A toothed rod 73 is rotatably connected to the back of the support rod 71. The toothed rod 73 meshes with the toothed disc 32. A threaded groove 74 is slidably connected to the surface of the support rod 71 through an extended sliding frame. The threaded groove 74 passes through the conical sealing ring 72. A connecting rod 75 is circumferentially hinged to the surface of the threaded groove 74. An internal pressure plate 76 is hinged to the surface of the connecting rod 75. Preferably, one end of the toothed rod 73 is fixedly connected to a screw 77, which is threaded inside the threaded groove 74. One end of the sliding frame extending from the surface of the support rod 71 is fixedly connected to a support plate 78. A folding slide groove 79 connected by a torsion spring is fixedly connected to the circumference of the surface of the support plate 78. A limiting slide rod 710 is slidably connected inside the folding slide groove 79. One end of the limiting slide rod 710 is fixedly connected to the inner pressure plate 7. An inclined block 711 is fixedly connected to the surface of the limiting slide rod 710, which functions to squeeze the folding slide groove 79 to unfold it. The other end of the limiting slide rod 710 is fixedly connected to an arc-shaped groove 712. All the arc-shaped grooves 712 can form a ring. A solid sealing ring 713 is embedded inside the arc-shaped groove 712. When the arc-shaped groove 712 unfolds through the limiting slide rod 710, it can drive the solid sealing ring 713 to open and seal one end of the steel pipe.

[0017] Preferably, the air pump 4 is connected to the toothed rod 73 and the screw 77 via an air pipe. The method of use and advantages of this invention: This vacuum insulation pipe strength performance testing fixture operates as follows: Figures 1 to 15As shown. In use, before clamping the pipe, the initial position of the outer pressure plate 55 in the coating detection mechanism 5 must be precisely pre-adjusted according to the outer diameter of the vacuum insulated pipe to be tested. This function is achieved by the adjustment mechanism 6. The operator first loosens the L-shaped support plate 62 fixed to the limiting slide rail 61 using conventional bolts 612, allowing the entire L-shaped support plate 62 assembly to slide along the surface of the annular fixing frame 51 for coarse adjustment to adapt to the approximate diameter range of the pipe. Then, precise fine adjustment is performed, followed by pulling the handle 69 outwards, causing the telescopic end of the spring telescopic rod 67 to move together, disengaging the retaining teeth 68 on its surface from the retaining ring 66, and simultaneously compressing the internal spring. In this state, turning the handle 69 drives the eccentric wheel 610, which is fixed to the fixed end of the spring telescopic rod 67, to rotate. The outer axis of the eccentric wheel 610 slides within the groove 611 at the upper end of the slide rod 63. Due to the eccentric effect, its rotational motion is converted into a drive to lift or lower the slide rod 63. The slide rod 63 slides vertically inside the limiting slide rail 61, and its lower end slot 64 is hinged to the rotating shafts on both sides of the outer pressure plate 55 via the L-shaped connecting rod 65. Therefore, the up and down movement of the slide rod 63 is transmitted through the L-shaped connecting rod 65 and is ultimately converted into precise adjustment of the tilt angle of the outer pressure plate 55. This adjustment mechanism ensures that all outer pressure plates 55 can form an initial contour that perfectly matches the outer diameter of the pipe to be tested. After the adjustment is in place, the handle 69 is released, and under the action of the spring return force, the extension end of the spring telescopic rod 67 drives the retaining tooth 68 to re-engage in the retaining ring 66. At the same time, the pin 612 fixed in the center of the eccentric wheel 610 also re-engages in the corresponding hole on the back of the toothed plate 52, forming a double lock and ensuring the positional stability of the outer pressure plate 55 during subsequent testing. It employs the principle of combining the linkage of eccentric wheel 610, slide bar 63, and spring self-locking to achieve stepless, precise, and self-locking adjustment of the coating contour. This allows a single tooling unit to quickly and accurately adapt to a series of pipes with different diameters, greatly improving the equipment's versatility and test preparation efficiency, and avoiding the cost and time consumption of configuring special molds for different pipe diameters. After the adjustment mechanism 6 is preset, the pipe to be tested is placed at the center of the coating detection mechanism 5, with one end of the pipe ready to be connected to the internal pressure detection mechanism 7. However, at this stage, the sealing assembly of the internal pressure detection mechanism 7 has not yet been deployed. The power source for external pressure detection is activated (e.g., a motor or cylinder that drives the gear set 53 to rotate, not explicitly shown in the figure but commonly chosen by those skilled in the art), and the power is transmitted to multiple gears 53 interconnected by universal joints 54. All gears 53 rotate synchronously, driving the circumferentially distributed toothed plates 52 that mesh with them to slide synchronously radially towards the center inside the annular fixed frame 51. The rotatable outer pressure plates 55, which are fixedly connected to the lower end of each toothed plate 52, retract inward synchronously until the inner surfaces of all the outer pressure plates 55 are completely in contact with the outer wall of the pipe. Subsequently, the system continuously applies a preset, constant standard pressure value.The gear set connected by the universal joint 54 ensures the absolute synchronous movement of all toothed plates 52 and the outer pressure plate 55, thereby applying highly uniform radial pressure to the outer wall of the pipe, perfectly simulating the uniform external load that the pipe may bear in a vacuum insulation environment. This uniform pressure application effectively avoids test data distortion or local plastic deformation of the pipe caused by stress concentration, providing a reliable data basis for accurately evaluating the external pressure resistance and structural stability of the pipe material. After maintaining constant pressure for a certain period of time, observe whether there are any signs of instability or damage in the pipe. After completion, the power source reverses, driving the outer pressure plate 55 back to the initial position. After the external pressure test is passed, the pipe remains in the working position, and then the internal pressure and sealing test are performed. First, the drive motor 31 of the drive mechanism 3 is started, and its output shaft drives the toothed plate 32 to rotate. The toothed rod 73 meshing with the toothed plate 32 then moves axially. The screw 77 at the front end of the rack 73 is screwed into the threaded groove 74 of the internal pressure detection mechanism 7. Since the rotation of the threaded groove 74 is restricted by the sliding frame on the support rod 71, the rotational drive of the screw 77 is converted into linear motion of the threaded groove 74 towards the inside of the pipe. Multiple connecting rods 75 at the front end of the threaded groove 74 are then pushed. These connecting rods 75 are respectively hinged to the circumferentially arranged internal pressure plates 76, thereby forcing all the internal pressure plates 76 to expand radially outward. The limiting slide rod 710, fixedly connected to the internal pressure plate 76, begins to slide inside the folded groove 79 supported by a torsion spring. During the sliding process, the inclined block 711 on the surface of the limiting slide rod 710 presses against the folded groove 79, forcing it to overcome the torsion spring force and unfold, thereby causing the arc-shaped grooves 712 at the ends of all the limiting slide rods 710 to combine together to form a complete rigid annular support structure. The solid sealing rings 713 embedded in each arc-shaped groove 712 are then radially expanded and tightly pressed against the inner wall of the pipe, forming a high-pressure sealing barrier. It cleverly transforms linear motion into radial sealing and supporting action through connecting rod 75 and inclined plane mechanism, achieving automatic centering and efficient high-pressure sealing inside the pipeline. This sealing structure unfolds uniformly, causing minimal damage to the pipeline's inner wall and effectively compensating for small inner diameter tolerances, ensuring absolute reliability of the seal during subsequent high-pressure testing. After the internal seal is established, air pump 4 is activated. Compressed gas output by air pump 4, reaching a preset standard test pressure value, is simultaneously introduced through air pipes into the connecting air passages inside the toothed rod 73 and screw 77, ultimately injecting into the sealed cavity formed by the inner pressure plate 76, solid sealing ring 713, and the pipeline's inner wall. The system maintains this constant internal pressure for a specified period. During this time, a high-precision pressure sensor continuously monitors pressure changes within the sealed cavity. This combines internal pressure strength testing and airtightness testing, applying a constant standard internal pressure to assess pipeline structural strength while directly judging the pipeline's sealing performance by monitoring whether this constant pressure decreases.This method simplifies the testing process, significantly improves testing efficiency, and ensures consistency in strength and sealing test conditions by using the same stable pressure source and monitoring system, resulting in more accurate and reliable test results. This provides comprehensive data support for the overall quality assessment of vacuum insulated pipes. After testing, the air pump 4 stops supplying air and depressurizes. Subsequently, the drive motor 31 reverses, driving the inner pressure plate 76 to contract via the aforementioned transmission chain. The solid sealing ring 713 disengages from the inner wall of the pipe, and the folding slide 79 resets under the action of the torsion spring. Finally, the pipe that has completed all testing items can be safely removed from the fixture. The above describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples of the present invention and are not intended to limit the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A testing fixture for the strength performance of a vacuum insulated pipe, comprising a workbench (1), characterized in that: The surface of the workbench (1) is provided with a cylinder (2), a drive mechanism (3) and an air pump (4); The drive mechanism (3) includes a drive motor (31) fixedly connected to the surface of the worktable (1), and a gear disk (32) is fixedly connected to one end of the output shaft of the drive motor (31). The surface of the workbench (1) is fixedly connected to a coating detection mechanism (5) for applying pressure to the outer wall of the pipe, and the surface of the coating detection mechanism (5) is provided with an adjustment mechanism (6) for adapting to pipes of different diameters. The surface of the workbench (1) is equipped with an internal pressure detection mechanism (7) for extending into the pipe to perform sealing and pressurization. The coating detection mechanism (5), the internal pressure detection mechanism (7), the drive mechanism (3) and the air pump (4) work together to perform external pressure detection, internal pressure detection and sealing detection of the pipeline in sequence.

2. The strength performance testing fixture for a vacuum insulated pipe according to claim 1, characterized in that: The coating detection mechanism (5) includes an annular fixed frame (51) fixedly connected to the surface of the workbench (1). Multiple toothed plates (52) are slidably connected to the inner circumference of the annular fixed frame (51). Gears (53) meshing with the toothed plates (52) are rotatably connected to the inner circumference of the annular fixed frame (51). The multiple gears (53) are circumferentially distributed, and adjacent gears (53) are connected by universal joints (54). The lower end of the toothed plate (52) is fixedly connected to a rotatable outer pressure plate (55).

3. The strength performance testing fixture for a vacuum insulated pipe according to claim 2, characterized in that: The adjustment mechanism (6) includes a limiting slide rail (61) fixedly connected to the surface of the annular fixing frame (51), an L-shaped support plate (62) is slidably connected to the surface of the limiting slide rail (61), and a slide rod (63) is slidably connected inside the limiting slide rail (61). The lower end of the slide bar (63) is fixedly connected to a slot (64), and an L-shaped connecting rod (65) is slidably connected inside the slot (64). The lower end of the L-shaped connecting rod (65) is fixedly connected to the rotating shaft of the outer pressure plate (55). The surface of the L-shaped support plate (62) is fixedly connected with a retaining ring (66), and the inside of the L-shaped support plate (62) is rotatably connected with a spring telescopic rod (67). The telescopic end of the spring telescopic rod (67) is fixedly connected with a retaining tooth (68), and a handle (69) is fixedly connected to one side of it. The fixed end of the spring telescopic rod (67) is fixedly connected to an eccentric wheel (610), and the upper end of the slide rod (63) is fixedly connected to a slot two (611). The outer axis of the eccentric wheel (610) is slidably connected to the inside of the slot two (611). The center of the eccentric wheel (610) is fixedly connected to a pin (612) for locking the toothed plate (52).

4. The strength performance testing fixture for a vacuum insulated pipe according to claim 3, characterized in that: The internal pressure detection mechanism (7) includes a support rod (71) fixedly connected to the surface of the workbench (1), a conical sealing ring (72) fixedly connected to the surface of the support rod (71), and a toothed rod (73) rotatably connected to the back of the support rod (71), the toothed rod (73) meshing with the toothed disc (32). The surface of the support rod (71) is slidably connected to a threaded groove (74) via a sliding frame. The threaded groove (74) passes through the conical sealing ring (72), and multiple connecting rods (75) are circumferentially hinged to its surface. An inner pressure plate (76) is hinged to the surface of the connecting rod (75).

5. The strength performance testing fixture for a vacuum insulated pipe according to claim 4, characterized in that: One end of the toothed rod (73) is fixedly connected to a screw (77), and the screw (77) is threadedly connected to the inside of the threaded groove (74); One end of the support rod (71) sliding frame is fixedly connected to a support plate (78). The surface circumference of the support plate (78) is connected to multiple folding grooves (79) by torsion springs. The inside of the folding grooves (79) is slidably connected to a limiting slide rod (710). One end of the limiting slide rod (710) is fixedly connected to the inner pressure plate (76).

6. The strength performance testing fixture for a vacuum insulated pipe according to claim 5, characterized in that: The surface of the limiting slide bar (710) is fixedly connected to an inclined block (711) for pressing and unfolding the folding slide groove (79). The other end of the limiting slide bar (710) is fixedly connected to an arc-shaped groove (712), and all the arc-shaped grooves (712) together form a ring. A solid sealing ring (713) is embedded inside the arc-shaped groove (712).

7. The strength performance testing fixture for a vacuum insulated pipe according to claim 6, characterized in that: The air pump (4) is connected to the inside of the toothed rod (73) and screw (77) through an air pipe, and is used to deliver gas at a constant pressure to the sealed space formed inside the pipe by the inner pressure plate (76) and the solid sealing ring (713).

8. The strength performance testing fixture for a vacuum insulated pipe according to claim 7, characterized in that: The drive motor (31) controls the expansion and contraction of the inner pressure plate (76) through the meshing of the drive gear plate (32) and the rack (73), and then through the transmission of the screw (77) and the threaded groove (74), thereby achieving the sealing and unsealing of the inside of the pipeline.

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