Multi-working-condition axial testing machine for self-anchoring connector steel pipe

Abstract

The invention discloses a multi-working-condition axial testing machine for a self-anchoring connector steel pipe, and belongs to the technical field of self-anchoring pipe performance test.The multi-working-condition axial testing machine comprises a rack, a displacement mechanism, a driving assembly and a sealing monitoring system, and two testing stations are symmetrically arranged on the rack in the axial direction; each test station comprises a self-anchoring pipe fixing device and a test pipe in butt joint with a to-be-tested self-anchoring pipe; the displacement mechanism is arranged between the two testing stations and is driven by the driving assembly to move, so that the testing pipes of the two testing stations generate axial reciprocating relative displacement relative to the corresponding self-anchoring pipes; the sealing detection system is used for testing the sealing performance of the self-anchoring pipe, and the testing machine can accurately simulate various axial displacement conditions of the pipeline in actual use through the cooperation of the displacement mechanism and the driving assembly, and can perform sealing performance detection when the self-anchoring pipe is in a dynamic displacement state. And the sealing retention capability of the self-anchoring interface under long-term dynamic displacement can be accurately evaluated.

Description

Technical Field

[0001] This invention belongs to the field of self-anchoring pipe performance testing technology, specifically relating to a multi-condition axial testing machine for self-anchoring interface steel pipes. Background Technology

[0002] Due to the combined effects of various factors, pipelines are subjected to complex and reciprocating axial displacement loads. Geologically, the settlement characteristics of different soil types vary significantly. Soft soil foundations may experience uneven settlement due to long-term stress or changes in groundwater, leading to axial displacement of the pipeline. Temperature fluctuations are also significant; pipeline materials expand and contract with temperature changes, and this thermal expansion and contraction effect can cause periodic axial expansion and contraction of the pipeline during day-night cycles or seasonal changes. In addition, changes in fluid pressure within the pipeline can also induce axial forces, and fluid impacts and pressure pulsations can all affect pipeline joints.

[0003] Traditional pipe joint testing machines have significant limitations in evaluating the performance of self-anchoring joints. Firstly, these machines are functionally limited, mostly only capable of simulating simple static or unidirectional axial displacement, failing to accurately reproduce the complex, reciprocating axial displacement loads experienced by pipelines in actual use. For instance, some machines can only apply axial forces of fixed magnitude and direction, unable to simulate dynamic and variable axial displacement caused by geological changes, temperature fluctuations, and other factors. This results in significant discrepancies between test results and actual conditions, making it difficult to accurately assess the performance of self-anchoring joints under real-world operating conditions.

[0004] Traditional methods for assessing sealing performance can only be performed under static or simple motion conditions, making it difficult to detect minute gas leaks that may occur during dynamic displacement of the self-anchoring interface. These minute leaks may gradually expand over long-term operation, eventually leading to serious safety incidents.

[0005] Therefore, it is necessary to develop a testing machine that can simulate the complex, reciprocating axial displacement loads borne by self-anchored steel pipes under various working conditions. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides a multi-condition axial testing machine for self-anchored steel pipes. This solves the problems of traditional pipe joint testing machines having limited functionality, difficulty in simulating complex reciprocating axial displacements, and inability to effectively evaluate the sealing and fatigue performance of self-anchored joints.

[0007] The objective of this invention can be achieved through the following technical solutions: A multi-condition axial testing machine for self-anchored steel pipes includes a frame, a displacement mechanism, a drive assembly, and a sealing monitoring system. Two test stations are symmetrically arranged along the axial direction on the frame. Each test station includes a self-anchored pipe fixing device and a test pipe that is connected to the self-anchored pipe to be tested. The displacement mechanism is positioned between two test stations and driven by the drive assembly to cause the test tubes at the two test stations to undergo axial reciprocating relative displacement relative to their respective self-anchoring tubes; the sealing monitoring system is used to test the sealing performance of the self-anchoring tubes.

[0008] Preferably, the displacement mechanism includes two cranks, a drive shaft, and two connecting rods; the drive shaft is coaxially arranged with the two cranks, the drive assembly drives the drive shaft to rotate, and one end of each of the two connecting rods is hinged to the eccentric point of the two cranks, and the other end is hinged to the test tube.

[0009] Preferably, the displacement mechanism further includes a displacement adjustment component, which includes a radial sliding groove disposed on the crank disc and an eccentric slider that can slide along the sliding groove. The hinge point of the connecting rod is located on the eccentric slider. A scale for calibrating the eccentricity is disposed next to the sliding groove, and the eccentric slider is locked by a locking bolt.

[0010] Preferably, the connecting rod includes a fixed rod and a hinged rod. The fixed rod is fixedly connected to the self-anchoring tube and coaxially connected to the self-anchoring tube. One end of the hinged rod is hinged to the fixed rod and the other end is hinged to the eccentric slider.

[0011] Preferably, the sealing monitoring system includes a monitoring module, a control module, and a media filling module; the monitoring module is axially arranged along the end face of the test tube that connects with the self-anchoring tube; the media filling module is located in the test tube and fills the test tube with the detection medium; the monitoring module monitors whether there is leakage of the detection medium at the interface, and the control module is used to collect the data from the monitoring module.

[0012] Preferably, the detection medium filled into the test tube by the medium filling module is a tracer gas; the monitoring module includes a sensor array arranged around the self-anchor pipe interface, and the sensitive elements of the sensor array are coated with a sensitive material that can react with the tracer gas; the sensor array is electrically connected to the control module through a signal line, and transmits electrical signals characterizing changes in electrical properties to the control module in real time.

[0013] Preferably, the tracer gas is a mixture of hydrogen and nitrogen, and the sensor array is a metal oxide semiconductor-based gas sensor whose resistance changes with the hydrogen concentration.

[0014] Preferably, the control module is connected to an angular displacement sensor located on the displacement mechanism. The control module acquires the rotation phase angle of the displacement mechanism detected by the angular displacement sensor in real time; determines the real-time relative displacement between the test tube and the self-anchoring tube based on the rotation phase angle; generates a target pressure control signal based on the real-time relative displacement; and outputs it to the medium filling module.

[0015] Preferably, the test tube is connected to the frame via a guide support assembly; the guide support assembly includes a linear guide rail fixed on the frame and a slider fixedly connected to the test tube and slidable on the linear guide rail to guide the test tube to reciprocate axially.

[0016] The beneficial effects of this invention are as follows: Traditional pipe joint testing machines are limited in function and cannot effectively simulate the complex, reciprocating axial displacement loads experienced by pipelines under real-world operating conditions. This testing machine, however, through the coordination of a displacement mechanism and drive components, can accurately simulate various axial displacement scenarios encountered by pipelines in actual use, including displacements of different magnitudes, frequencies, and directions. This provides test conditions closer to real-world conditions for evaluating the performance of self-anchoring joints. Compared to traditional testing methods, this testing machine can perform tests under dynamic displacement conditions on the self-anchoring pipe, more accurately assessing the sealing performance of the self-anchoring joint under long-term dynamic displacement. Attached Figure Description

[0017] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a front view structural diagram of the multi-condition axial testing machine for self-anchored interface steel pipe provided in one embodiment of the present invention; Figure 2 This is a cross-sectional view of the multi-condition axial testing machine for self-anchored steel pipes provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the self-anchoring pipe in an axial displacement state provided in one embodiment of the present invention; Figure 4 This is a schematic diagram of the installation structure of the guide support component provided in one embodiment of the present invention; Figure 5 This is a diagram showing the control relationship for the performance detection of the self-anchoring pipe shaft provided in one embodiment of the present invention; Legend: 1. Frame; 2. Drive assembly; 3. Displacement mechanism; 311. Fixed rod; 312. Hinge rod; 32. Drive shaft; 33. Crank disc; 4. Sealing monitoring system; 41. Medium filling module; 42. Monitoring module; 5. Test tube; 6. Self-anchoring tube; 71. Sliding groove; 72. Eccentric block; 81. Linear guide rail; 82. Slider. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0020] Traditional pipe joint testing machines typically have limited functionality and are unable to simulate the complex and reciprocating axial displacement loads that pipes experience under real-world conditions. Consequently, they cannot effectively assess the sealing performance and fatigue resistance of self-anchored joints under long-term dynamic displacement.

[0021] like Figures 1-5 As shown, a multi-condition axial testing machine for self-anchored steel pipe includes a frame 1, a displacement mechanism 3, a drive assembly 2, and a sealing monitoring system 4. Two test stations are symmetrically arranged along the axial direction on the frame 1. Each test station includes a self-anchored pipe 6 fixing device and a test pipe 5 that is connected to the self-anchored pipe 6 to be tested. The displacement mechanism 3 is set between the two test stations and driven by the drive assembly 2 to make the test tubes 5 of the two test stations generate axial reciprocating relative displacements relative to their respective self-anchoring tubes 6; the sealing monitoring system 4 is used to test the sealing performance of the self-anchoring tubes 6.

[0022] Two self-anchoring pipes 6 to be tested are fixed to the self-anchoring pipe 6 fixing devices at two test stations. The two test pipes 5 are then connected and initially sealed to their corresponding self-anchoring pipe 6 interfaces. The drive assembly 2 is activated, outputting a displacement mechanism 3 that rotates or moves linearly to the center. This mechanical structure forces an axial relative displacement between the two parts of the interface (the fixed self-anchoring pipe 6 and the moving test pipe 5) according to a preset pattern, simulating the axial force on the pipe interface caused by actual working conditions such as foundation settlement, temperature changes, and pressure fluctuations. Under these stringent mechanical conditions, a highly sensitive sealing monitoring system 4 determines whether the sealing element of the self-anchoring interface can still function effectively, thus achieving a comprehensive assessment of the reliability and durability of the self-anchoring interface.

[0023] In summary, traditional pipe joint testing machines have limited functionality and struggle to simulate the complex, reciprocating axial displacement loads experienced by pipes under real-world conditions. This testing machine, through the cooperation of the displacement mechanism 3 and the drive assembly 2, can accurately simulate various axial displacement scenarios encountered by pipes in actual use, including displacements of different magnitudes, frequencies, and directions. This provides test conditions closer to real-world conditions for evaluating the performance of self-anchoring joints. Compared to traditional testing methods, this testing machine can perform tests under dynamic displacement conditions on the self-anchoring pipe 6, more accurately evaluating the sealing performance of the self-anchoring joint under long-term dynamic displacement.

[0024] In one embodiment, the displacement mechanism 3 includes two crank disks 33, a drive shaft 32, and two connecting rods. The drive shaft 32 is coaxially arranged with the two crank disks 33, and the drive assembly 2 drives the drive shaft 32 to rotate. One end of each connecting rod is hinged to an eccentric point on one of the two crank disks 33, and the other end is hinged to a test tube 5. The circular motion of the crank disks 33 is converted into linear motion of the eccentric block 72 by the connecting rods. Specifically, a common drive shaft 32 is used to drive the two crank disks 33 to rotate synchronously. One end of each connecting rod is hinged to an eccentric point on one of the two crank disks 33, and the other end is hinged to the two test tubes 5. Thus, when the drive shaft 32 rotates, the eccentric points on the two crank disks 33 perform circular motion. Through the push and pull of the connecting rods, the circular motion is converted into linear reciprocating motion of the test tube 5. The connecting rods, as intermediate components, convert rotational power into linear power.

[0025] When testing self-anchoring pipes 6 of different specifications or under different test standards, it is necessary to simulate axial displacements of different amplitudes. The displacement mechanism 3 with a fixed eccentricity cannot meet this multi-condition testing requirement. In one embodiment, the displacement mechanism 3 further includes a displacement adjustment component. The displacement adjustment component includes a radial sliding groove 71 on the crank disc 33 and an eccentric block 72 that can slide along the sliding groove 71. The hinge point of the connecting rod is located on the eccentric block 72. A scale for calibrating the eccentricity is provided next to the sliding groove 71, and the eccentric block 72 is locked by a locking bolt. The output stroke is directly changed by changing the equivalent crank radius (eccentricity) in the displacement mechanism 3. The solution is to open a radial sliding groove 71 on the crank disc 33 and configure an eccentric block 72 that can slide within the groove. The connecting rod is hinged to this eccentric block 72. By loosening the locking bolt and sliding the eccentric block 72, moving it away from or towards the center, the distance between the hinge point and the rotation center of the crank disc 33 can be continuously changed.

[0026] In one embodiment, the connecting rod includes a fixed rod 311 and a hinged rod 312. The fixed rod 311 is fixedly connected to the self-anchoring tube 6 and coaxially connected to the self-anchoring tube 6. One end of the hinged rod 312 is hinged to the fixed rod 311 and the other end is hinged to the eccentric block 72. The height of the hinged end of the connecting rod 312, which is hinged to the crank disk 33, will exhibit a regular trend of height change as the crank disk 33 rotates. If the two ends of the connecting rod are directly hinged to the self-anchor tube 6 and the crank disk 33, the connecting rod will move at the center of the intersection point with the self-anchor tube 6 when the crank disk 33 rotates, instead of driving the self-anchor tube 6 to move axially. Therefore, it is necessary to connect the fixed rod 311 to the crank disk 33, so that the eccentric movement of the hinged rod 312 on the crank disk 33 can be converted into the linear movement of the fixed rod 311 driving the self-anchor tube 6, thereby realizing the axial movement of the self-anchor tube 6. At the same time, the hinged connection allows the self-anchor tube 6 to also rotate with the test tube 5, simulating the real connection environment.

[0027] In one embodiment, the sealing monitoring system 4 includes a monitoring module 42, a control module, and a media filling module 41. The monitoring module 42 is axially arranged along the end face of the test tube 5 that is connected to the self-anchoring pipe 6. The media filling module 41 is located on the test tube 5 and fills the test tube 5 with a detection medium. The monitoring module 42 monitors whether there is leakage of the detection medium at the interface, and the control module is used to collect data from the monitoring module 42. After the test tube 5 is connected to the self-anchoring pipe 6, the media filling module 41 fills the sealed space formed by the test tube 5 and the interface with a detection medium, such as gas, to a predetermined pressure. The displacement mechanism 3 starts working, driving the test tube 5 to reciprocate. At the same time, the monitoring module 42 arranged around the interface continuously collects data. The software algorithm inside the control module analyzes and processes the received data. Once characteristic signals indicating leakage, such as the appearance of gas or bubble images, are detected, a leak is determined, and the time, location, and severity of the leak can be recorded. Traditional detection methods are insufficiently sensitive to detect minute gas leaks, making accurate detection difficult. This leads to the failure to promptly identify potential sealing problems, thus affecting the accuracy of overall performance evaluation of self-anchored steel pipes. In one embodiment, the detection medium filled into the test tube 5 by the medium filling module 41 is a tracer gas. The monitoring module 42 includes a sensor array arranged around the interface of the self-anchored pipe 6. The sensitive elements of the sensor array are coated with a sensitive material that reacts with the tracer gas. The sensor array is electrically connected to the control module via a signal line, transmitting electrical signals characterizing changes in electrical properties to the control module in real time. The medium filling module 41 is responsible for filling the test tube 5 with tracer gas. The tracer gas has unique physicochemical properties, such as good diffusivity and chemical reactivity, making it suitable as a "marker" for detection. During the filling process, the pressure and flow rate of the filled gas are precisely controlled to ensure a stable gas environment in the test tube 5 that conforms to actual working conditions. When the displacement mechanism 3 causes the test tube 5 to reciprocate axially relative to the self-anchored pipe 6, the self-anchored pipe 6 is in a dynamic displacement state. During this process, if there is a problem with the seal at the connection point of the self-anchor pipe 6, the tracer gas in the test tube 5 will escape from the leak point. Due to the good diffusivity of the tracer gas, even if the leakage is very small, the leaked gas will quickly diffuse into the surrounding space, providing a captureable signal source for subsequent detection. The sensor array in the monitoring module 42 is evenly arranged around the interface of the self-anchor pipe 6, forming a comprehensive monitoring network. The sensitive elements of the sensor array are coated with a sensitive material that can react with the tracer gas. When the leaked tracer gas diffuses to the sensor surface, it will react chemically with the sensitive material. This chemical reaction will cause changes in the electrical properties of the sensitive material, such as changes in parameters like resistance, capacitance, or conductivity. Different tracer gases react with sensitive materials in different ways, but all will cause changes in measurable electrical properties.

[0028] In one embodiment, the tracer gas is a mixture of hydrogen and nitrogen at a specific concentration. The sensor array is a metal oxide semiconductor-based gas sensor whose resistance changes with the hydrogen concentration. Hydrogen is lightweight, highly diffusive, and moderately chemically reactive, allowing it to quickly and uniformly distribute within the test tube 5 and rapidly diffuse into the surrounding environment in the event of a leak. Nitrogen, as an inert gas, dilutes the hydrogen concentration and regulates the overall properties of the mixed gas, ensuring suitable detection characteristics and safety. Specifically, when leaked hydrogen diffuses to the sensor surface, hydrogen molecules adsorb onto the surface of the metal oxide semiconductor material. The hydrogen molecules react chemically with oxygen ions on the material surface, causing a change in the electron concentration and consequently altering the sensor's resistance. The higher the hydrogen concentration, the more hydrogen molecules are adsorbed, and the more significant the change in resistance. For example, in the absence of hydrogen leakage, the sensor resistance remains at a relatively stable baseline value; when hydrogen leakage occurs, the resistance decreases with increasing hydrogen concentration.

[0029] In dynamic axial displacement testing, the internal volume of the pipe interface changes periodically with the reciprocating motion of the test pipe 5. If the internal medium pressure remains constant, it is impossible to simulate the complex working condition of pressure and displacement coupling in a real pipeline. Manual or open-loop pressure control cannot keep up with the rapid changes in volume. Therefore, an intelligent control system that can accurately adjust the internal medium pressure in real time and automatically based on the axial displacement is needed. In one embodiment, the control module is connected to an angular displacement sensor located on the displacement mechanism 3. The control module acquires the rotation phase angle of the displacement mechanism 3 detected by the angular displacement sensor in real time; determines the real-time relative displacement between the test pipe 5 and the self-anchoring pipe 6 based on the rotation phase angle; generates a target pressure control signal based on the real-time relative displacement; and outputs it to the medium filling module 41. By monitoring the rotation phase angle of the displacement mechanism 3 in real time through the angular displacement sensor, and because the displacement mechanism 3 and the test pipe 5 have a definite geometric relationship, the control module can accurately calculate the real-time relative displacement. Then, the control module calculates a target pressure value in real time based on this displacement and a preset pressure-displacement relationship model. Finally, the control module compares the target pressure with the actual pressure fed back by the pressure sensor, and drives the proportional valve and other actuators in the medium filling module 41 to operate through a closed-loop control algorithm, precisely controlling the inflow or outflow of the medium so that the actual pressure closely follows the changes in the target pressure. When the test tube 5 is subjected to thrust and tension from the connecting rod, it may produce undesirable displacement or rotation other than axial movement, such as slight radial runout or yaw. In one embodiment, the test tube 5 is connected to the frame 1 via a guide support assembly. The guide support assembly includes a linear guide rail 81 fixed on the frame 1 and a slider 82 fixedly connected to the test tube 5 and slidable on the linear guide rail 81 to guide the test tube 5 to reciprocate axially.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A multi-condition axial testing machine for self-anchored steel pipes, characterized in that, It includes a frame, a displacement mechanism, a drive assembly, and a sealing monitoring system. Two test stations are symmetrically arranged along the axial direction on the frame. Each test station includes a self-anchoring pipe fixing device and a test pipe that is connected to the self-anchoring pipe to be tested. The displacement mechanism is positioned between two test stations and driven by the drive assembly to cause the test tubes at the two test stations to undergo axial reciprocating relative displacement relative to their respective self-anchoring tubes; the sealing monitoring system is used to test the sealing performance of the self-anchoring tubes.

2. The multi-condition axial testing machine for self-anchored steel pipes according to claim 1, characterized in that, The displacement mechanism includes two cranks, a drive shaft, and two connecting rods; the drive shaft is coaxially arranged with the two cranks, and the drive assembly drives the drive shaft to rotate; one end of each of the two connecting rods is hinged to the eccentric point of the two cranks, and the other end is hinged to the test tube.

3. The multi-condition axial testing machine for self-anchored steel pipes according to claim 2, characterized in that, The displacement mechanism further includes a displacement adjustment assembly, which includes a radial sliding groove disposed on the crank disc and an eccentric slider that can slide along the sliding groove. The hinge point of the connecting rod is located on the eccentric slider. A scale for calibrating the eccentricity is disposed next to the sliding groove, and the eccentric slider is locked by a locking bolt.

4. The multi-condition axial testing machine for self-anchored steel pipes according to claim 3, characterized in that, The connecting rod includes a fixed rod and a hinged rod. The fixed rod is fixedly connected to the self-anchoring tube and coaxially connected to the self-anchoring tube. One end of the hinged rod is hinged to the fixed rod and the other end is hinged to the eccentric slider.

5. The multi-condition axial testing machine for self-anchored steel pipes according to claim 1, characterized in that: The sealing monitoring system includes a monitoring module, a control module, and a media filling module; the monitoring module is axially arranged along the end face where the test tube and the self-anchoring tube meet; the media filling module is located in the test tube and fills the test tube with the detection medium; the monitoring module monitors whether there is leakage of the detection medium at the interface, and the control module is used to collect the data of the monitoring module.

6. The multi-condition axial testing machine for self-anchored steel pipes according to claim 5, characterized in that: The detection medium introduced into the test tube by the medium filling module is a tracer gas; the monitoring module includes a sensor array arranged around the self-anchor pipe interface, and the sensitive elements of the sensor array are coated with a sensitive material that can react with the tracer gas. The sensor array is electrically connected to the control module via signal lines, transmitting electrical signals characterizing changes in electrical properties to the control module in real time.

7. The multi-condition axial testing machine for self-anchored steel pipes according to claim 6, characterized in that, The tracer gas is a mixture of hydrogen and nitrogen, and the sensor array is a gas sensor based on metal oxide semiconductor, whose resistance value changes with the hydrogen concentration.

8. The multi-condition axial testing machine for self-anchored steel pipes according to claim 5, characterized in that, The control module is connected to the angular displacement sensor located on the displacement mechanism. The control module acquires the rotation phase angle of the displacement mechanism detected by the angular displacement sensor in real time. Based on the rotation phase angle, the control module determines the real-time relative displacement between the test tube and the self-anchoring tube. Based on the real-time relative displacement, the control module generates a target pressure control signal and outputs it to the medium filling module.

9. The multi-condition axial testing machine for self-anchored steel pipes according to claim 1, characterized in that, The test tube is connected to the frame via a guide support assembly; the guide support assembly includes a linear guide rail fixed to the frame and a slider fixedly connected to the test tube and sliding on the linear guide rail to guide the test tube to reciprocate axially.

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