Flexible array coplanar capacitance imaging device for detecting thermal insulation pipeline defects

Abstract

The utility model discloses a flexible array type electrode coplanar capacitance imaging device for detecting thermal insulation pipeline defects. The device is mainly composed of a pipeline mechanical movement device, a flexible array coplanar capacitive sensor and the like, the pipeline mechanical movement device carries the flexible array coplanar capacitive sensor, stable advancing detection is guaranteed, and meanwhile 360-degree dead-corner-free measurement can be conducted by rotating around a pipeline; the flexible array coplanar capacitive sensor ensures that the equivalent lift-off heights of the coplanar capacitive sensor and the thermal insulation pipeline are the same, and can adapt to thermal insulation pipelines with different curvatures; the problem that the defect depth detection precision is reduced due to the fact that the nonuniformity of the electric field between the pole plate and the detected target caused by the curved surface target aggravates the nonlinearity of the distribution of the electric field in the depth direction and the spacing of the pole plate can be well solved, the effective field intensity is ensured, and the detection precision is improved; the optimal response can be obtained under different measurement depths through different electrode pairs, and the reliability of the sensor in practical application can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a defect detection device, relates to the technical field of heat preservation pipeline, and particularly relates to a flexible array coplanar capacitive imaging device for detecting defects of heat preservation pipeline. BACKGROUND

[0002] Heat preservation pipeline becomes an indispensable key part in the fields of petrochemical industry, heating supply, urban infrastructure, etc., and plays a crucial role in guaranteeing the efficient operation of the system, reducing energy loss, reducing cost, and ensuring the safety and stability of the entire system. However, heat preservation pipeline may be affected by external environment, material aging, etc. during long-term use, and defects such as corrosion and cracks may occur, thereby affecting the safe operation of the pipeline. In addition, the heat preservation pipeline is buried in the soil and is affected by factors such as soil medium composition and temperature. Corrosion occurs due to cracking of the heat preservation layer, affecting the safe operation of the pipeline, and may also cause environmental pollution. However, at present, frequent reports of pipeline leakage accidents have a serious negative impact on the pipeline industry. Therefore, the detection level of heat preservation pipeline needs to be developed and continuously improved to reduce economic losses and reduce the impact.

[0003] Traditional pipeline detection methods such as ultrasonic non-destructive testing technology require the application of coupling agent on the surface of the measured object and the probe must be attached to the measured object, which may cause a certain degree of pollution to the surface of the measured object and the probe; the radiation risk to the operator may be caused by the ray detection; the infrared imaging is limited by factors such as temperature change and surface characteristics; the probe needs to penetrate the heat preservation layer and directly contact the pipeline metal surface for the alternating current decay method (PCM) and the direct current potential gradient method (DCVG), which may cause damage to the pipeline heat preservation layer.

[0004] Therefore, the present application provides a flexible array coplanar capacitive imaging device for detecting defects of heat preservation pipeline. SUMMARY

[0005] In order to solve the problems in the background art, the present application provides a flexible array coplanar capacitive imaging device for detecting defects of heat preservation pipeline.

[0006] The technical scheme adopted by the present application is as follows:

[0007] A flexible array coplanar capacitive imaging device for detecting defects of heat preservation pipeline comprises:

[0008] A pipeline mechanical movement device is used to carry and drive the flexible array capacitive sensor device to move along the pipeline.

[0009] Flexible array capacitive sensor, which detects the defects on the surface and inside of the pipe;

[0010] Electrode pair switching plate, which is used for selecting the electrode pairs on the flexible array capacitive sensor and amplifying the signal;

[0011] LCR digital bridge, which is used for measuring the capacitance value change of each electrode pair in real time.

[0012] The pipe mechanical movement device comprises a support frame, springs, connecting rods, omni-directional wheels I, a screw structure, and a carrying device. The support frame is composed of a top cover plate and two side plates. Inclined supports are arranged between the two side plates and the top cover plate. Two connecting rods are arranged horizontally and towards the center of the device at the bottom of the two side plates through the springs. The omni-directional wheels I are arranged oppositely at the ends of the two connecting rods and rotate through a motor. The screw structure is arranged vertically and penetrates through the top cover plate. The carrying device is arranged at the bottom of the screw structure. The flexible array capacitive sensor is arranged at the bottom of the carrying device. The distance between the flexible array capacitive sensor and the pipe can be adjusted by moving the carrying device up and down through the screw structure.

[0013] The springs are arranged inside the side plates through spring bases. Supports are arranged between the connecting rods and the top cover plate for supporting and fixing. The support frame is a I-shaped part. The support is a steel plate for strengthening the structure. The support frame and the support jointly support and fix.

[0014] The two omni-directional wheels I are oppositely arranged and distributed on the two sides of the pipe when working.

[0015] The top surface of the carrying device is connected with the screw structure. The omni-directional wheels II are arranged at the front and back of the carrying device. The omni-directional wheels II are located directly above the pipe and have rotating shafts parallel to the elongation direction of the pipe. The rotating shafts of the omni-directional wheels II are perpendicular to the rotating shafts of the omni-directional wheels I. The hard plane, the soft plane, and the flexible array capacitive sensor are sequentially arranged below the carrying device through a hexagonal column. The curvature of the soft plane is adjusted through the screws arranged on the hard plane. The soft plane and the flexible array capacitive sensor are connected through screws. The mounting positions of the omni-directional wheels II and the hexagonal column are provided with notches for adjusting the mounting positions of the omni-directional wheels II and the hexagonal column.

[0016] The material of the hexagonal column is nylon. The screws between the soft plane and the flexible array capacitive sensor are made of nylon. In order to insulate the flexible array capacitive sensor from other parts made of aluminum alloy and avoid parasitic capacitance, the material of the hard plane is aluminum alloy. The soft plane is made of spring steel.

[0017] The flexible array capacitive sensor is an FPC double-sided panel, which is composed of a plurality of coplanar electrode pairs, eight pads are welded on the FPC double-sided panel, and the plurality of coplanar electrode pairs are respectively connected to the FPC and PCB conversion plate through the pads; the flexible array capacitive sensor further comprises an FPC and PCB conversion plate arranged on one side of the flexible array capacitive sensor, and an SMA port I on the FPC and PCB conversion plate is connected to the electrode pair switching plate.

[0018] Different electrode pairs are used to measure the defect position of the pipeline at different depths.

[0019] The electrode pair switching plate is a PCB circuit board, which comprises a driving port, a sensing port and a manual relay; the SMA port II on the electrode pair switching plate is connected to the SMA port I on the FPC and PCB conversion plate in one-to-one correspondence; the driving port and the sensing port of the electrode pair switching plate are connected to the LCR digital bridge; and the manual relay serves as a switch to artificially control the selection of the electrode pair.

[0020] The beneficial effects of the present application are as follows:

[0021] The flexible array electrode coplanar capacitive imaging device of the present application carries the flexible array coplanar capacitive sensor through the pipeline mechanical motion device, can rotate around the pipeline at 360° without dead angle measurement while stably detecting, and can fully cover the surface of the pipeline to avoid defect omission. The flexible array coplanar capacitive sensor can ensure the same equivalent lifting height as the heat preservation pipeline and adapt to different curvature pipelines, and effectively solve the problems of non-uniformity of the electric field caused by the curved target and non-linearity of the electric field distribution and the electrode plate spacing, ensure the effective field strength, and significantly improve the defect depth detection accuracy. Different electrode pairs can obtain the best response at different measurement depths, enhance the reliability of the sensor in complex actual working conditions, accurately detect all kinds of defects in deep and shallow layers, reduce misjudgment and omission, and provide a more stable, comprehensive, accurate and reliable technical solution for heat preservation pipeline defect detection. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the pipeline mechanical motion device of the present application;

[0023] Figure 2 is a schematic diagram of the device carrying the flexible array capacitive sensor of the present application;

[0024] Figure 3 is a schematic diagram of the flexible array capacitive sensor of the present application;

[0025] Figure 4 is a schematic diagram of the FPC and PCB conversion plate of the present application;

[0026] Figure 5 is a schematic diagram of the electrode pair switching plate of the present application;

[0027] In the diagram: Top cover plate (1), lead screw (2), upper support (3), diagonal support (4), side plate (5), bracket (6), support (7), spring base (8), spring (9), connecting rod (10), bearing (11), motor (12), omnidirectional wheel I (13), mounting device (14), hexagonal column (15), hard plane (16), soft plane (17), flexible array capacitive sensor (18), SMA port I (19), solder pad (20), drive port (21), sensing port (22), manual relay (23), SMA port II (24) Detailed Implementation

[0028] The invention will now be further described with reference to the accompanying drawings.

[0029] A flexible array coplanar capacitance imaging device for detecting defects in insulated pipes can move along the insulated pipe and operate stably both along the pipe direction and around the pipe, suitable for pipes of different diameters. Figure 1 As shown, the device consists of a pipe mechanical motion device, a flexible array capacitive sensor, an electrode pair switching board, an FPC to PCB conversion board, and an LCR digital bridge. The pipe mechanical motion device includes an upper cover plate 1, a lead screw 2, an upper support 3, an inclined support 4, a side plate 5, a bracket 6, a support 7, a spring base 8, a spring 9, a connecting rod 10, a bearing 11, a motor 12, an omnidirectional wheel I 13, and a mounting device 14. Except for the omnidirectional wheel I 13 (the hub is made of aluminum alloy, and the small wheels are made of rubber) and the motor 12, all the aforementioned components are made of aluminum alloy. The upper cover plate 1 and the inclined support 4 have been designed for weight reduction, and the overall structural strength is increased by adding supports. The distance between the sensor and the insulated pipe can be adjusted by the lead screw 2, and the distance can also be adjusted by the spring 9, ensuring that the mechanical motion device does not deviate from the track during rotation. The two omnidirectional wheels II at the front and rear prevent the mechanical motion device from tipping over, ensuring that the flexible array capacitive sensor can scan and detect on the same horizontal plane. The motor 12 provides power and controls the speed.

[0030] like Figure 2 As shown, the device equipped with the flexible array capacitive sensor comprises a hexagonal post 15 (made of nylon), a hard plane 16 (made of aluminum alloy), a soft plane 17, and a flexible array capacitive sensor 18. The hexagonal post 15 is made of nylon to insulate the flexible array capacitive sensor 18 from other components made of aluminum alloy, preventing parasitic capacitance. The hard plane 16 has three threaded holes on one side, allowing adjustment of the curvature of the soft plane using screws to accommodate insulation pipes with varying curvatures. The hard plane 16 and soft plane 17 are connected by a hexagonal post; the soft plane 17 is connected to the flexible array capacitive sensor 18 by screws made of nylon. The omnidirectional wheel II and the hexagonal post 15 have slotted designs at their mounting positions for easy position adjustment.

[0031] like Figure 3 As shown, the flexible array capacitive sensor is an FPC double-sided board with a length of 70mm, a width of 50mm, and a thickness of 0.11mm. The outer copper foil is 1 / 3 ounce thick, and the cover film PI (polyimide) has a thickness of 12.5um / AD:15um. The electrode is 15mm long and 4mm wide. To avoid deformation of the FPC board caused by the soldered wires, eight pads are connected to a PCB board, realizing the transformation from FPC board to PCB board.

[0032] like Figure 4 As shown, the FPC to PCB conversion board is a PCB circuit board with a length of 106mm and a width of 33mm. The SMA port I19 has advantages such as small size, low signal loss and electromagnetic shielding performance. It is connected to the electrode pair switching board, and the pad 20 is soldered to the flexible array capacitive sensor and fixed again with screws to ensure that the flexible array capacitive sensor is firmly connected to the FPC to PCB conversion board.

[0033] like Figure 5 As shown, the electrode pair switching board is a PCB circuit board with a length of 162mm and a width of 96mm; the SMA port II 24 is connected to the FPC and PCB conversion board in a one-to-one correspondence, and the drive port 21 and the sensing port 22 are connected to the LCR digital bridge; the manual relay 23 acts as a switch, which can manually control the selection of the electrode pair.

[0034] This invention combines mechanical motion with capacitive sensing technology to achieve non-contact, efficient detection of surface and internal defects in insulated pipes. First, the mechanical motion device is installed on the surface of the insulated pipe to be tested. Omnidirectional wheels at the bottom of the device contact the pipe via rubber surfaces, and the overall frame is supported by an aluminum alloy bracket and a spring structure. The vertical distance between the sensor and the pipe surface is adjusted by rotating a screw structure, maintaining it at a preset equivalent lift height (typically 1-3 mm). Simultaneously, the spring structure provides adaptive buffering, ensuring stable contact between the sensor and the pipe as the device moves across the surface. For pipes of different diameters (e.g., 100 mm to 500 mm), the curvature of the soft surface is altered by adjusting screws on the hard surface, ensuring a tight fit between the flexible array capacitive sensor and the pipe's curved surface, avoiding uneven electric field distribution caused by curvature mismatch.

[0035] The omnidirectional wheel is driven by a motor, and the device moves uniformly along the pipeline axis or circumferentially. The flexible array capacitive sensor is composed of a plurality of coplanar electrode pairs, the electrode pairs are connected with a PCB conversion plate through a FPC soft plate, and an SMA port on the conversion plate transmits signals to an electrode pair switching plate through a low-loss coaxial line. An operator selects a specific detection area by sequentially switching different electrode pairs through a manual relay. An LCR digital bridge measures the capacitance value change of each electrode pair in real time, and analyzes the electrode depth response curve (the measurement depth range of different electrode pairs is optimized through finite element simulation).

[0036] The simulation is used to calibrate each pair of electrodes on the flexible coplanar array capacitive sensor and the optimal measurement depth (each pair of electrodes corresponds to a different measurement depth, the first pair of electrodes corresponds to a measurement depth of 0-5 mm, the second pair of electrodes corresponds to a measurement depth of 5-10 mm, the third pair of electrodes corresponds to a measurement depth of 10-15 mm, and the fourth pair of electrodes corresponds to a measurement depth of 15-20 mm).

[0037] During measurement, different electrode pairs are switched in turn from shallow to deep until the host computer detects a change in capacitance. When the sensor passes through a pipeline defect area (such as corrosion or cracking), the capacitance value will fluctuate abnormally due to changes in electric field distribution. The data processing unit generates a two-dimensional capacitance distribution map of the pipeline surface through an image reconstruction algorithm according to the capacitance change data, and intuitively displays the position, size and depth information of the defect. For example, shallow defects (such as surface cracking of the insulation layer) are detected by small-pitch electrode pairs, while deep defects (such as metal layer corrosion) are detected by large-pitch electrode pairs.

[0038] The omnidirectional wheel and spring composite structure adopted by the present application ensures smooth movement on complex surfaces (such as uneven insulation layers), avoids data distortion caused by vibration or tilting, reduces electromagnetic interference through the SMA port metal shield shell and gold-plated contact points, and ensures the stability of high-frequency signal transmission. The combination of flexible sensor and nylon insulating piece effectively suppresses the interference of parasitic capacitance on the detection result.

Claims

1. A flexible array coplanar capacitive imaging device for detecting defects in a pipe, characterized in that, It comprises: A pipeline mechanical movement device for carrying and driving the flexible array capacitive sensor device to move along the pipeline; A flexible array capacitive sensor for detecting defects on the surface and inside of the pipeline; An electrode pair switching plate for selecting the electrode pairs on the flexible array capacitive sensor and for amplifying the signal; An LCR digital bridge for measuring the capacitance value changes of each electrode pair in real time.

2. The flexible array coplanar capacitive imaging device for detecting defects of the pipeline according to claim 1, wherein the pipeline mechanical movement device comprises a support frame, springs (9), connecting rods (10), omnidirectional wheels I (13), a screw structure, and a carrying device (14). The support frame is composed of a top cover plate (1) and two side plates (5), and an inclined support (4) is arranged between the two side plates (5) and the top cover plate (1). The two side plates (5) are connected with two connecting rods (10) arranged horizontally and towards the center of the device through springs (9) at the bottom of the two side plates (5). The two connecting rods (10) are installed with oppositely arranged omnidirectional wheels I (13) at the end of the two connecting rods (10), and the omnidirectional wheels I (13) are controlled to rotate through a motor (12). The top cover plate (1) is installed with a screw structure arranged in the vertical direction and penetrating through the top cover plate (1), and the screw structure is installed with the carrying device (14) at the bottom of the screw structure. The carrying device (14) is installed with the flexible array capacitive sensor (18) at the bottom of the carrying device (14). The carrying device (14) is driven to move up and down through the screw structure to adjust the distance between the flexible array capacitive sensor and the pipeline.

3. The flexible array coplanar capacitive imaging device for detecting defects of the pipeline according to claim 2, wherein the springs (9) are installed in the inner side of the side plates (5) through spring bases (8). A support (7) is arranged between the connecting rods (10) and the top cover plate (1) for supporting and fixing. The oppositely arranged two omnidirectional wheels I (13) are distributed on the two sides of the pipeline when working.

4. The flexible array coplanar capacitive imaging device for detecting defects of the pipeline according to claim 2, wherein the top surface of the carrying device (14) is connected with the screw structure, omnidirectional wheels II are installed on the front and back of the carrying device (14), the omnidirectional wheels II are located directly above the pipeline, the rotating shafts of the omnidirectional wheels II are parallel to the elongation direction of the pipeline, and the rotating shafts of the omnidirectional wheels II are perpendicular to the rotating shafts of the omnidirectional wheels I (13). A hard plane (16), a soft plane (17), and the flexible array capacitive sensor (18) are sequentially installed below the carrying device (14) through a hexagonal column (15). The curvature of the soft plane is adjusted through the screws arranged on the hard plane (16), and the soft plane (17) is connected with the flexible array capacitive sensor (18) through screws. Grooves are arranged at the installation positions of the omnidirectional wheels II and the hexagonal column (15) for adjusting the installation positions of the omnidirectional wheels II and the hexagonal column (15).

5. The flexible array coplanar capacitive imaging device for detecting defects of the pipeline according to claim 4, wherein ​ ​ ​ The hexagonal column (15) material is nylon, and the screw between the soft plane (17) and the flexible array capacitive sensor (18) is made of nylon; the hard plane (16) material is aluminum alloy; and the soft plane is made of spring steel.

6. The flexible array coplanar capacitive imaging device for detecting defects in an insulated pipe of claim 1, wherein, The flexible array capacitive sensor is a FPC double-sided panel, which is composed of a plurality of coplanar electrode pairs, and eight pads (20) are welded on the FPC double-sided panel, and the plurality of coplanar electrode pairs are respectively connected to the FPC and PCB conversion board through the pads. The flexible array capacitive sensor further comprises an FPC and PCB conversion board arranged on one side of the flexible array capacitive sensor, and an SMA port I (19) on the FPC and PCB conversion board is connected to the electrode pair switching board.

7. A flexible array coplanar capacitive imaging device for detecting defects in a pipe for holding a temperature, according to claim 6, characterized in that, Different electrode pairs are used to measure the defect position of the pipeline at different depths.

8. The flexible array coplanar capacitive imaging device for detecting defects in an insulated pipe of claim 1, wherein, The electrode pair switching board is a PCB circuit board, which comprises a driving port (21), a sensing port (22) and a manual relay (23); the SMA port II (24) on the electrode pair switching board is connected to the SMA port I (19) on the FPC and PCB conversion board one by one; the driving port (21) and the sensing port (22) of the electrode pair switching board are connected to the LCR digital bridge; and the manual relay (23) is used as a switch to artificially control the selection of the electrode pair.

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