Internal detection device and method for aging of internally-inserted polyethylene pipeline

Abstract

The invention belongs to the technical field of pipeline aging detection, and particularly relates to an internally-inserted polyethylene pipeline aging internal detection device and method. The device at least comprises a detector capable of moving in the pipeline; the cable rack is provided with a multifunctional cable in a winding mode, one end of the multifunctional cable is connected with the detector, and the other end of the multifunctional cable is connected with a pressure source, a power source and a control terminal. Based on the nondestructive testing technology provided by the invention, the aging state of the in-service interpenetrating polyethylene pipeline of the oil field can be tested on site, the buried pipeline does not need to be excavated, sampling analysis is not needed, and the influence on production operation is very small.

Description

Technical Field

[0001] This invention belongs to the field of pipeline aging detection technology, specifically relating to an internal detection device and method for aging of internally inserted polyethylene pipelines. Background Technology

[0002] Polyethylene (PE) materials have the advantage of corrosion resistance and are widely used in oilfields for crude oil transportation pipelines. A common practice is to use PE pipes as anti-corrosion linings for carbon steel pipelines through an internal insertion process. However, the service environment presents various aging factors such as high temperature, mechanical loads, media penetration, and chemical effects, which can cause performance degradation in PE pipes and, in severe cases, pipeline failure.

[0003] Conventional methods for evaluating the aging of polyethylene pipes generally rely on analytical testing methods such as mechanical property testing, surface microstructure, and oxidation induction time. These methods require sampling and analysis of the pipes, which is difficult to implement for pipelines already in service. Furthermore, the electromagnetic eddy current defect detection devices commonly used for metal pipes are not suitable for polyethylene pipes. This is primarily because aging leads to deterioration of polyethylene material properties but does not necessarily cause macroscopic defects, and polyethylene lacks electromagnetic properties, thus failing to meet the basic requirements for electromagnetic testing.

[0004] Although document 202111592634.7, "A Method for Characterizing Aging of In-Service Polyethylene Pipes Based on Ultrasonic Testing," discloses that ultrasonic velocity based on pipe wall thickness direction can characterize pipe aging, the method described can only be tested from the outside of the in-service polyethylene pipe. Therefore, it cannot obtain the accurate wall thickness at the test location, which will inevitably introduce errors into the test results. Moreover, this method is not applicable to internally penetrating pipes because the interface between the carbon steel base pipe and the polyethylene liner is a strong ultrasonic reflection interface. Ultrasonic waves incident from the outer wall of the carbon steel base pipe will be reflected at the interface and cannot enter the polyethylene liner.

[0005] Currently, there is an urgent need in oilfields for an aging detection technology that is suitable for internally inserted polyethylene pipes without excavation or sampling. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an internal aging detection device and method for internally inserted polyethylene pipelines. Based on the non-destructive testing technology provided by this invention, the aging status of in-service polyethylene pipelines in oil fields can be tested on-site. Buried pipelines require no excavation or sampling analysis, minimizing the impact on production operations.

[0007] The technical solution provided by this invention is as follows:

[0008] An internal aging detection device for internally inserted polyethylene pipes, comprising at least:

[0009] A detector that can move inside a pipe;

[0010] A retractable cable rack is provided, on which a multifunctional cable is wound. One end of the multifunctional cable is connected to the detector, and the other end of the multifunctional cable is connected to a pressure source, a power source, and a control terminal.

[0011] Based on the above technical solution, by allowing the detector to enter the pipeline to acquire data, and by analyzing and processing the data through the control terminal, the aging status of polyethylene pipelines in service in the oilfield can be tested on-site.

[0012] Specifically, the detector includes:

[0013] A support frame, wherein the support frame is equipped with a walking device;

[0014] And an airbag fitted around the outer periphery of the support frame, with several probes fixedly installed on the outer wall of the airbag, each probe having a magnetic thickness measurement module and an ultrasonic testing module;

[0015] The walking device, the airbag, and each of the probes are respectively connected to the multi-functional cable.

[0016] Based on the above technical solution, after the device arrives at the test area, the expansion of the airbag allows the magnetic thickness measurement module and the ultrasonic testing module to fit against the pipe wall in order to obtain test data.

[0017] Furthermore, a camera is provided at the front end of the support frame, and the camera is connected to the multi-functional cable.

[0018] Based on the above technical solution, the heat fusion joint of the polyethylene pipe (i.e. the starting position of each section of polyethylene pipe) can be found by the video images captured by the camera. The position of the detector in the pipe to be tested can be determined by the length of the extended functional cable.

[0019] Specifically:

[0020] The support frame is a cylindrical structure;

[0021] The outer wall of the support frame is fitted with a cylindrical tube, which is rotatably connected to the support frame, and the airbag is fitted tightly onto the cylindrical tube.

[0022] Furthermore, the tube has an eccentric center of gravity structure, with the center of gravity of the tube located directly below the axis.

[0023] Based on the above technical solution, the weight of the tube itself can be used to ensure that each probe maintains a certain clock direction on the cross-section of the detector (i.e., the cross-section of the pipe).

[0024] Furthermore, the airbag includes annular portions at both ends and a tubular portion in the middle, with the outer diameters of the two annular portions being the same and both being larger than the outer diameter of the tubular portion.

[0025] Specifically:

[0026] Each probe is fixedly arranged around the outer periphery of the tubular portion;

[0027] Each of the probes is connected to the multifunctional cable via a line disposed on the surface of the airbag.

[0028] Further:

[0029] Several grooves are provided on the surface of the annular portion near one end of the multifunctional cable.

[0030] Alternatively, a plurality of conduits may be provided on the surface of the annular portion near one end of the multifunctional cable.

[0031] Furthermore, the multi-functional cable is equipped with scale lines for recording the length of take-up and undo. Alternatively, the cable rack has a take-up and undo length counting function, for example, by setting guide rollers on the cable and a counter for the number of rotations of the guide rollers to calculate the take-up and undo length.

[0032] The present invention also provides a method for detecting the aging of internally inserted polyethylene pipes, using the device described in the present invention to perform aging detection of polyethylene pipes.

[0033] The method for detecting aging in internally inserted polyethylene pipes includes the following steps:

[0034] The airbag inflates, and each probe fits against the tube wall;

[0035] The magnetic thickness measurement function of the probe is activated to test the wall thickness of the polyethylene liner between the carbon steel base tube and each probe, and the data is transmitted back to the control terminal for calculation of the ultrasonic test path.

[0036] The ultrasonic function of the probe is activated to test the ultrasonic signal along the wall of the polyethylene liner at each probe location, and the signal is transmitted back to the control terminal for analysis of the aging degree of the polyethylene pipe.

[0037] The beneficial effects of this invention are:

[0038] 1) The testing method and testing device of the present invention are based on non-destructive testing technology, which can conduct on-site testing of the aging status of polyethylene pipelines in service in oil fields. Buried pipelines do not require excavation or sampling analysis, and have little impact on production operations.

[0039] 2) The detection method and testing device of the present invention are based on the actual working conditions of polyethylene pipelines in service in oil fields. Ultrasonic coupling is achieved by using the residual crude oil inside the pipeline. There is no need for pre-heat washing to remove oil, which avoids the harmful effects of high temperature and surfactants on polyethylene pipes. Moreover, the absence of additional coupling agent simplifies the equipment structure.

[0040] 3) The testing device of the present invention is based on the actual technical level in the field of ultrasonic nondestructive testing and is easy to implement.

[0041] 4) The improved method of the present invention can also be applied to separate polyethylene or other thermoplastic oil pipelines. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the overall structure of the internal aging detection device for internally inserted polyethylene pipes provided by the present invention.

[0043] Figure 2 This is a schematic diagram of the detector part of the internal aging detection device for internally inserted polyethylene pipes provided by the present invention.

[0044] Figure 3 This is a structural diagram of an airbag for an internal aging detection device for internally inserted polyethylene pipes provided by the present invention.

[0045] Figure 4 This is another structural diagram of the airbag in the internal aging detection device for internally inserted polyethylene pipes provided by the present invention.

[0046] Figure 5 It refers to pipe samples and testing methods.

[0047] Appendix Figures 1 to 5 The structures represented by each label are listed below:

[0048] 1. Detector, 2. Multifunctional cable, 3. Cable rack, 4. High-pressure air hose, 5. Power cord, 6. Signal cable, 7. Pressure source, 8. Power supply, 9. Control terminal, 10. Support frame, 11. Cylinder body, 12. Camera, 13. Walking device, 14. Airbag, 15. Probe, 16. Polyethylene inner liner tube, 17. Test carbon steel base tube, 18. Cable trough, 19. Conduit. Detailed Implementation

[0049] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0050] It should be noted that when a part or component is considered to be "connected to," "located on," or "assembled" to another part or component, it can be directly mounted on the other part or component, or it may be located in an intermediate part or component. The terms "left," "right," "upper," "lower," and similar expressions used in this document are for illustrative purposes only.

[0051] Example 1

[0052] like Figure 1As shown, the internal aging detection device for in-line polyethylene pipelines includes: a detector 1 that can move inside the pipeline; a retractable cable rack 3, on which a multi-functional cable 2 is wound, one end of which is connected to the detector 1, and the other end of which is connected to a pressure source 7, a power supply 8, and a control terminal 9. Based on this technical solution, by allowing the detector to enter the pipeline to acquire data, and by analyzing and processing the data through the control terminal, the aging status of in-service polyethylene pipelines in oil fields can be tested on-site.

[0053] Example 2

[0054] like Figure 1 , 2 As shown, the internal aging detection device for polyethylene pipes includes: a detector 1 that can move inside the pipe; a retractable cable rack 3, on which a multi-functional cable 2 is wound, one end of which is connected to the detector 1, and the other end of which is connected to a pressure source 7, a power supply 8 and a control terminal 9.

[0055] The detector 1 includes: a support frame 10, on which a walking device 13 is mounted; and an airbag 14 sleeved around the outer periphery of the support frame 10. Several probes 15 are fixedly mounted on the outer wall of the airbag 14, each probe 15 having a magnetic thickness measurement module and an ultrasonic testing module. The walking device 13, the airbag 14, and each probe 15 are respectively connected to a multi-functional cable 2.

[0056] Based on this technical solution, by allowing the detector to enter the pipeline to acquire data, and then analyzing and processing the data through a control terminal, the aging status of polyethylene pipelines in service in oil fields can be tested on-site. After the device reaches the test area, the expansion of the air bladder allows the magnetic thickness measurement module and the ultrasonic testing module to fit against the pipe wall to acquire test data.

[0057] Example 3

[0058] like Figure 1 , 2 As shown, the internal aging detection device for polyethylene pipes includes: a detector 1 that can move inside the pipe; a retractable cable rack 3, on which a multi-functional cable 2 is wound, one end of which is connected to the detector 1, and the other end of which is connected to a pressure source 7, a power supply 8 and a control terminal 9.

[0059] The detector 1 includes: a support frame 10, on which a walking device 13 is provided; and an airbag 14 sleeved on the outer periphery of the support frame 10, on which a plurality of probes 15 are fixedly provided, each probe 15 having a magnetic thickness measurement module and an ultrasonic testing module; the walking device 13, the airbag 14 and each probe 15 are respectively connected to a multi-functional cable 2.

[0060] The support frame 10 is a cylindrical structure. A cylindrical tube 11 is fitted on the outer wall of the support frame 10. The cylindrical tube 11 is rotatably connected to the support frame 10, and the airbag 14 is tightly fitted on the cylindrical tube 11.

[0061] Example 4

[0062] like Figure 1 , 2 As shown, the internal aging detection device for polyethylene pipes includes: a detector 1 that can move inside the pipe; a retractable cable rack 3, on which a multi-functional cable 2 is wound, one end of which is connected to the detector 1, and the other end of which is connected to a pressure source 7, a power supply 8 and a control terminal 9.

[0063] The detector 1 includes: a support frame 10, on which a walking device 13 is mounted; and an airbag 14 fitted around the outer periphery of the support frame 10. Several probes 15 are fixedly mounted on the outer wall of the airbag 14, each probe 15 having a magnetic thickness measurement module and an ultrasonic testing module. The walking device 13, the airbag 14, and each probe 15 are connected to a multi-functional cable 2.

[0064] The support frame 10 is a cylindrical structure. A cylindrical tube 11 is fitted on the outer wall of the support frame 10. The cylindrical tube 11 is rotatably connected to the support frame 10, and the airbag 14 is tightly fitted on the cylindrical tube 11.

[0065] The airbag 14 includes annular portions at both ends and a tubular portion in the middle. The outer diameters of the two annular portions are the same and both are larger than the outer diameter of the tubular portion. Probes 15 are fixedly mounted around the outer periphery of the tubular portion. Each probe 15 is connected to a multi-functional cable 2 via wiring on the surface of the airbag 14.

[0066] Example 5

[0067] Based on Examples 2 to 4, such as Figure 2 As shown, the internal aging detection device for polyethylene pipes includes: a detector 1 that can move inside the pipe; a retractable cable rack 3 with a multi-functional cable 2 wound around it, one end of which is connected to the detector 1, and the other end of which is connected to a pressure source 7, a power supply 8, and a control terminal 9. The detector 1 includes: a support frame 10 with a walking device 13; and an airbag 14 fitted around the support frame 10, with several probes 15 fixedly mounted on the outer wall of the airbag 14. Each probe 15 has a magnetic thickness measurement module and an ultrasonic testing module. The walking device 13, the airbag 14, and each probe 15 are connected to the multi-functional cable 2.

[0068] The support frame 10 has a camera 12 at its front end, and the camera 12 is connected to a multi-functional cable 2.

[0069] Based on this technical solution, by inserting a detector into the pipeline to acquire data, and then analyzing and processing the data through a control terminal, the aging status of in-service polyethylene pipelines in oil fields can be tested on-site. Once the device reaches the test area, the expansion of the air bladder allows the magnetic thickness measurement module and the ultrasonic testing module to adhere to the pipe wall to acquire test data. Video images captured by a camera can identify the heat fusion joints in the polyethylene pipeline, and the position of the detector within the pipeline can be determined by measuring the length of the extended functional cable.

[0070] Example 6

[0071] Based on Examples 3 and 4, such as Figure 2 As shown, the internal aging detection device for polyethylene pipes includes: a detector 1 that can move inside the pipe; a retractable cable rack 3 with a multi-functional cable 2 wound around it, one end of which is connected to the detector 1, and the other end of which is connected to a pressure source 7, a power supply 8, and a control terminal 9. The detector 1 includes: a support frame 10 with a walking device 13; and an airbag 14 fitted around the support frame 10. Several probes 15 are fixedly mounted on the outer wall of the airbag 14, each probe 15 having a magnetic thickness measurement module and an ultrasonic testing module. The walking device 13, the airbag 14, and each probe 15 are connected to the multi-functional cable 2. The support frame 10 is a cylindrical structure. A tube 11 is fitted around the outer wall of the support frame 10, and the tube 11 is rotatably connected to the support frame 10. The airbag 14 is tightly fitted onto the tube 11.

[0072] The tube 11 has an eccentric center of gravity structure, with its center of gravity located directly below the axis. Based on this technical solution, the weight of the tube itself can ensure that each probe maintains a certain clock orientation on the detector cross-section.

[0073] Example 7

[0074] Based on Example 4, such as Figure 3 As shown, several conduits 19 are provided on the surface of the annular portion near one end of the multi-functional cable 2.

[0075] Example 8

[0076] Based on Example 4, such as Figure 4 As shown, several grooves 18 are provided on the surface of the annular portion near one end of the multi-functional cable 2.

[0077] Example 9

[0078] like Figure 1 , 2As shown, the internal aging detection device for polyethylene pipes consists of a detector 1, a multi-functional cable 2, a cable rack 3, a pressure source 7, a power supply 8, and a control terminal 9. The detector 1 can enter the pipe to be inspected and collect signals. The multi-functional cable 2 integrates a high-pressure gas pipe 4, a power line 5, and a signal line 6, which connect the detector 1 to the pressure source 7, the power supply 8, and the control terminal 9, respectively, and serves to transmit high-pressure gas and electrical energy, control commands, and signals to the detector 1. The cable rack 3 is used for winding and unwinding the multi-functional cable 2. The pressure source 7 is used to provide compressed gas to the detector 1. The power supply 8 is used to provide electrical energy to the detector 1. The control terminal 9 is used to issue action commands to the detector 1 and to display and process the signals returned by the detector 1.

[0079] like Figure 2 As shown, the detector 1 consists of a support frame 10, a cylinder 11, an airbag 14, and a probe 15. Several walking devices 13, such as electric wheels, are installed on the peripheral walls at both ends of the support frame 10 for supporting and moving the detector 1 inside the pipe to be inspected. A camera 12 is installed on the end face of the support frame 10 facing the forward direction, providing illumination and image acquisition functions for capturing video images of the pipe's inner wall. A multi-functional cable 2 is connected to the end face of the support frame 10 facing away from the forward direction. The cylinder 11 adopts an eccentric center of gravity design, and a rotatable movable connection is used between the cylinder 11 and the support frame 10 to utilize the weight of the cylinder 11 itself. This design ensures that each probe 15 maintains a consistent clock direction on the cross-section of the detector 1, i.e., the pipe cross-section, facilitating the determination of the clock direction position at the test point; gas, electricity, and signal communication are achieved between the cylinder body 11 and the support frame 10; an air bladder 14 is installed on the outside of the cylinder body 11, which expands radially after compressed gas is injected into it; an array of probes 15 is arranged circumferentially on the air bladder 14, which can move radially synchronously with the air bladder 14; the probes 15 integrate magnetic thickness measurement and ultrasonic testing functions, and there are power and signal lines connecting the probes 15 and the cylinder body 11; necessary drive units, signal acquisition units, and other modules are installed inside the cylinder body 11.

[0080] By observing the video images captured by the camera 12 through the control terminal 9, the starting position of the heat fusion joint of the polyethylene pipe, i.e., each section of polyethylene pipe, can be found. Combined with the length of the extended functional cable 2, the position of the detector 1 in the pipe to be tested can be determined.

[0081] During ultrasonic testing, the probe 15 is coupled to the inner wall of the polyethylene liner 16 through the crude oil residue on the pipe wall.

[0082] Example 10

[0083] Methods for detecting aging in internally inserted polyethylene pipes:

[0084] like Figure 5As shown, detector 1 moves inside the pipe under test, locating the test position using the extended length of functional cable 2 and video images captured by camera 12. Upon reaching the test position, compressed gas is injected into airbag 14, causing it to expand radially and adhere tightly to the inner wall of the polyethylene liner 16, simultaneously ensuring that each probe 15 is pressed against the inner wall of the polyethylene liner 16. The magnetic thickness measurement function of probe 15 is activated to measure the wall thickness of the polyethylene liner 16 between the carbon steel base pipe 17 and each probe 15, transmitting the data back to control terminal 9 and recording it for calculating the "sound path" of the ultrasonic test. The ultrasonic function of probe 15 is activated to measure the ultrasonic signal along the pipe wall direction at each probe 15 location, transmitting the data back to control terminal 9 and recording it for analyzing the aging degree of the polyethylene pipe. The air pressure inside airbag 14 is then released, allowing the detector to resume movement.

[0085] Based on the ultrasonic signals collected by probe 15, physical quantities characterizing the aging degree of materials, such as ultrasonic velocity and acoustic impedance, can be calculated using preset calculation formulas in control terminal 9. The correspondence between the above physical quantities and the aging degree of polyethylene pipes can be obtained using existing technologies.

[0086] Example 11

[0087] Based on Example 9, for stand-alone polyethylene pipelines used for oil transportation, a magnetic marker can be installed at a selected location on the outer wall of the pipeline. The magnetic marker must be tightly fitted to the outer wall of the polyethylene pipeline, covering the circumference of the polyethylene pipeline, and have sufficient axial length, such as a sleeve made of carbon steel. Its operation is as follows: when detector 1 moves inside the pipeline to the vicinity of the expected position, the magnetic thickness measurement function of probe 15 is activated. When probe 15 displays a continuous detection signal, it indicates that detector 1 is at the magnetic marker position, i.e., the test position has been reached. Then, testing can be performed using conventional methods.

[0088] Example 12

[0089] 1) Test object

[0090] A buried, internally inserted ethylene crude oil pipeline with a polyethylene liner pipe specification of d. n 80 SDR11, with an outer base pipe made of carbon steel. The pipeline is 1km long, and internal inspections are required at 200m intervals, totaling 4 locations (200m, 400m, 600m, and 800m).

[0091] 2) Testing equipment

[0092] Building such Figure 1The test apparatus shown includes: six probes 15, evenly spaced circumferentially, with an ultrasonic testing function of 2.25MHz longitudinal wave; a high-purity nitrogen cylinder as the pressure source 7, with a pressure regulator limiting the gas pressure injected into the airbag 14; and an industrial laptop as the control terminal 9.

[0093] 3) Testing process

[0094] Insert the inner detector 1 into one end of the pipe to be tested. After confirming that it is working properly, continue to move forward until the length of the line is 200m and then stop. Then, perform the test as described above to obtain the longitudinal wave ultrasonic echo signals of the 6 probes 15 at this test position. Use the secondary echo peak to calculate the ultrasonic velocity, that is, obtain the ultrasonic velocity at 6 positions on the cross-section of the pipe wall at 200m of the pipe and store it. Complete the test at the next 3 test positions in sequence and record the data. Control the inner detector 1 to reverse and move it out of the pipe to be tested. The test is completed.

[0095] The aging status of the pipeline can be analyzed by comparing the ultrasonic velocity at different distances in the pipeline with the mathematical model of aging relationship established in the early stage.

[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this description, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An internal aging detection device for internally inserted polyethylene pipes, characterized in that, At least including: A detector that can move inside a pipe (1); A retractable cable rack (3) is provided, on which a multi-functional cable (2) is wound. One end of the multi-functional cable (2) is connected to the detector (1), and the other end of the multi-functional cable (2) is connected to a pressure source (7), a power supply (8), and a control terminal (9).

2. The internal aging detection device for internally inserted polyethylene pipes according to claim 1, characterized in that, The detector (1) includes: A support frame (10) is provided with a walking device (13); And an airbag (14) sleeved on the outer periphery of the support frame (10), and a number of probes (15) are fixedly installed on the outer wall of the airbag (14), each of the probes (15) having a magnetic thickness measurement module and an ultrasonic testing module; The walking device (13), the airbag (14), and each of the probes (15) are respectively connected to the multi-functional cable (2).

3. The internal aging detection device for internally inserted polyethylene pipes according to claim 2, characterized in that: A camera (12) is provided at the front end of the support frame (10), and the camera (12) is connected to the multi-functional cable (2).

4. The internal aging detection device for internally inserted polyethylene pipes according to claim 2, characterized in that: The support frame (10) is a cylindrical structure; The outer wall of the support frame (10) is fitted with a tube (11), the tube (11) is rotatably connected to the support frame (10), and the airbag (14) is fitted onto the tube (11).

5. The internal aging detection device for internally inserted polyethylene pipes according to claim 4, characterized in that: The tube (11) has an eccentric center of gravity structure, with the center of gravity of the tube (11) located directly below the axis.

6. The internal aging detection device for internally inserted polyethylene pipes according to any one of claims 2 to 5, characterized in that: The airbag (14) includes annular portions at both ends and a tubular portion in the middle. The outer diameters of the two annular portions are the same and both are larger than the outer diameter of the tubular portion.

7. The internal aging detection device for internally inserted polyethylene pipes according to claim 6, characterized in that: Each of the probes (15) is fixedly arranged around the outer periphery of the tubular portion; Each of the probes (15) is connected to the multifunctional cable (2) via a line provided on the surface of the airbag (14).

8. The internal aging detection device for internally inserted polyethylene pipes according to claim 7, characterized in that: A plurality of grooves (18) are provided on the surface of the annular portion near one end of the multifunctional cable (2); Alternatively, a plurality of conduits (19) may be provided on the surface of the annular portion near one end of the multifunctional cable (2).

9. A method for detecting aging in internally inserted polyethylene pipes, characterized in that: The apparatus described in any one of claims 1 to 8 is used to perform aging tests on polyethylene pipes.

10. The method for detecting aging of internally inserted polyethylene pipes according to claim 9, characterized in that, Includes the following steps: The airbag (14) is inflated and expanded, and each of the probes (15) is attached to the tube wall; The magnetic thickness measurement function of the probe (15) is activated to test the wall thickness of the polyethylene liner between the carbon steel base tube and each probe (15), and the result is transmitted back to the control terminal (9) to calculate the sound path of the ultrasonic test. The ultrasonic function of the probe (15) is activated to test the ultrasonic signal in the direction of the polyethylene inner liner pipe wall at each probe (15) position, and the signal is transmitted back to the control terminal (9) for analysis of the aging degree of the polyethylene pipe.

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