An adjustable camber wedge, a sealing material service state testing device and method

Abstract

The application discloses a wedge with adjustable camber, a device and a method for testing the service state of sealing material, and in-situ detects the sealing rubber material of electrical equipment such as operating converter transformer and the like. By using the different reflection intensities of ultrasonic waves in low-density rubber material, air and high-density metal material, whether the sealing material of large electrical equipment is damaged or leaks is distinguished. On the basis of the metal detection of the phased array ultrasonic wave, a special-shaped probe wedge is developed through targeted research and development, a nondestructive testing method for in-situ detection of the rubber part of the electrical equipment and a special form of wedge are developed. The method avoids the need of disassembling the equipment in the traditional sealing detection, is not only high in operation and maintenance cost and long in time consumption, but also possible to cause new sealing hidden dangers in secondary assembly, and the electrical equipment is high in value, and the loss in one-time shutdown maintenance can reach hundreds of thousands of yuan. The detection process is simple, and the personnel operation is convenient, so that the application provides an efficient and powerful detection means for the safe use of the electrical equipment.

Description

Technical Field

[0001] This invention belongs to the field of nondestructive testing technology, specifically relating to an adjustable curvature wedge, a testing device and method for the service status of sealing materials. Background Technology

[0002] With the rapid development of the power industry, large electrical equipment such as transformers, converter transformers, GIS switchgear, and converter valves play a crucial role in the power grid system. These devices typically contain complex sealing structures to seal critical insulating media such as SF6 gas and insulating oil, as well as cooling circulating media. The reliability of the sealing structure directly affects the long-term operational safety of the equipment and the overall stability of the power grid. Leakage can not only lead to equipment failure but also cause environmental pollution and safety accidents. Therefore, the testing of the service condition of sealing materials in electrical equipment is of paramount importance.

[0003] In existing operation and maintenance systems, the inspection of the sealing condition of large electrical equipment mainly relies on traditional periodic maintenance methods. This method typically requires shutting down and disassembling the equipment to remove internal rubber seals (such as O-rings and gaskets) for visual inspection or performance testing. However, this inspection method has significant limitations. First, large electrical equipment is expensive, and a single shutdown can result in substantial direct and indirect economic losses, reaching hundreds of thousands of yuan or even higher. Second, the disassembly and assembly process is time-consuming and requires the participation of a large number of professional technicians. For example, disassembling and assembling just one flange may require several skilled workers to spend several hours, leading to high operation and maintenance costs. More importantly, the disassembly process itself carries risks. If there are deviations in the reassembly, it is easy to introduce new sealing problems, resulting in a "repairing only leads to more leaks" dilemma. In addition, due to the limited maintenance cycle (usually only a window of one week to ten days per year), it is difficult to monitor the condition of the seals in real time, often failing to detect and address potential sealing failure risks in a timely manner.

[0004] To address the destructive nature and high costs associated with disassembly and inspection, the industry has explored various non-destructive testing (NDT) techniques for in-situ flaw detection in equipment. Currently, commonly used NDT methods include X-ray inspection, magnetic particle inspection, and infrared detection. However, these methods all face significant technical bottlenecks when inspecting the internal rubber sealing materials of large electrical equipment.

[0005] Specifically, while X-ray inspection technology boasts strong penetrating power, its equipment is bulky, inconvenient to operate on-site, and emits strong electromagnetic radiation, requiring strict protective measures and resulting in high inspection costs. More importantly, because rubber sealing materials are low-density materials, their attenuation coefficient for X-rays is low, and the contrast difference with metal casings and air is small, leading to low imaging resolution and difficulty in effectively identifying minute defects or aging conditions within the rubber material. Magnetic particle inspection technology is only applicable to ferromagnetic materials and is completely unsuitable for non-ferromagnetic rubber components encased within metal equipment. Infrared inspection technology, while simple to operate, has limited detection depth, typically only detecting surface or near-surface defects, and is highly susceptible to interference from factors such as material surface emissivity, ambient temperature, and wind speed, making it difficult to guarantee the accuracy and stability of the inspection results.

[0006] In summary, existing technologies lack an in-situ non-destructive testing method that can effectively penetrate metal casings, perform high-precision testing on low-density rubber materials, and is applicable to complex field environments. Therefore, a novel testing technology is urgently needed to achieve non-destructive, in-situ, and efficient assessment of the service condition of rubber seals inside large electrical equipment. Summary of the Invention

[0007] The purpose of this invention is to solve the problem that existing non-destructive testing methods cannot achieve in-situ non-destructive testing of internal rubber seals in large electrical equipment.

[0008] The objective of this invention is achieved through the following technical solution: An adjustable curvature wedge includes multiple strip wedges hinged together to form a track-like structure; the shape of the track-like structure can be adjusted to wrap around curved surfaces of different radii; when the adjustable curvature wedge is used for testing, each strip wedge is connected to an ultrasonic probe.

[0009] Preferably, the hinge is a connection of the strip wedge block via multiple hinges.

[0010] Preferably, the strip wedge is rectangular.

[0011] Preferably, the materials used for the strip-shaped wedge include: plexiglass, epoxy resin, and polystyrene.

[0012] Based on the same inventive concept, the present invention also provides a service condition testing device for rubber sealing materials, which includes: an ultrasonic flaw detector and the adjustable curvature wedge; the adjustable curvature wedge is connected to the probe of the ultrasonic flaw detector.

[0013] Based on the same inventive concept, the present invention also provides a method for testing the service condition of rubber sealing materials, the method comprising: Establish a focusing mode based on the material, thickness, and number of phased array probe elements of the equipment part to be inspected, and import it into the ultrasonic flaw detector; The number of strip wedges in the adjustable curvature wedge block is determined based on the curvature of the test surface at the test location. Coupling agent is applied to the probe contact surface of the strip wedge, and the phased array probe of the ultrasonic flaw detector is fixed to each of the strip wedges one by one. Remove debris from the test surface and apply coupling agent to the test surface. Then, attach the workpiece contact surface of the adjustable curvature wedge to the test surface. The sealing material is scanned using ultrasound, and the scan data is collected and compared with a database to determine the sealing condition.

[0014] Preferably, the phased array probe has 8, 16, 24, 32, 60, 128 or 256 elements.

[0015] Preferably, the test area includes the outer circumferential surface of the joint flange.

[0016] Preferably, the wedge is a special type of wedge with an adjustable curved surface radius. The special type of wedge is composed of multiple rectangular wedges connected by hinges. The probe connection position is arranged in the middle of each wedge and does not coincide with the connection position. The depth of the connection position inserted into the wedge is adjustable to control the radius of the curved surface wrapped by the wedge and adapt to pipes with different radii.

[0017] Preferably, the material of the test part is one of aluminum and aluminum alloys, carbon steel, stainless steel, copper and copper alloys.

[0018] Preferably, the thickness of the test area is between 10 and 500 mm.

[0019] Preferably, the sealing material includes nitrile rubber, ethylene propylene diene monomer (EPDM) rubber, fluororubber, silicone rubber, fluorosilicone rubber, and special rubbers.

[0020] Preferably, the sealing material includes O-rings, U-rings, V-rings, Y-rings, H-rings, and gaskets.

[0021] Preferably, the scanning mode includes electronic line scanning, sector scanning, or composite scanning.

[0022] Preferably, the impurities include: oil stains and rust-preventive coatings.

[0023] Preferably, the coupling agent includes water, engine oil, butter, petrolatum, silicone oil, polyvinyl alcohol, or paraffin.

[0024] Preferably, the comparison database for distinguishing sealing conditions includes: determining the service status of the sealing material by comparing the waveform characteristics of the scanned data with a pre-stored sealing status database, wherein the service status includes good sealing, poor sealing effect, and missing sealing parts.

[0025] Preferably, the determination of a good seal includes: after the ultrasonic wave penetrates the metal, it is absorbed at the sealing material. If the intensity of the reflected signal of the A-scan of the ultrasonic flaw detector is lower than a first preset threshold, and the C-scan interface displays a preset color line representing the low reflected signal intensity, then the seal is determined to be good.

[0026] Preferably, the determination of poor sealing effect includes: if the intensity of the reflected signal of the A-scan of the ultrasonic flaw detector is higher than the first preset threshold and lower than the second preset threshold, and the C-scan interface displays a preset color line representing a higher reflected signal intensity, then the sealing effect is determined to be poor.

[0027] Preferably, the determination of the missing sealing part includes: if the intensity of the A-scan reflection signal of the ultrasonic flaw detector is higher than the second preset threshold, and the C-scan interface displays a preset color line representing the high reflection signal intensity, then the sealing part is determined to be missing.

[0028] In this invention, the 'first preset threshold' and 'second preset threshold' are not fixed values, but are determined in advance through comparative calibration tests based on the specific material, thickness, and sealing specifications of the device under test. The determination logic is based on the physical nature of the different reflection intensities of ultrasonic waves at the interfaces of different acoustic impedance media (metal, rubber, air). The specific determination process is as follows: 1. Determination of the first preset threshold (intact benchmark calibration): Before testing, a simulated test block with the same material and thickness as the electrical equipment under test is selected, and a standard seal of matching specifications and in good condition is installed inside it. An A-scan is performed on this intact seal using the same phased array probe, wedge, and scanning parameters as in the actual test, to obtain the reference reflected signal intensity at the 'intact rubber-metal' interface after the ultrasonic wave penetrates the metal. The reflected signal intensity value in this intact state is set as the 'first preset threshold'. In actual testing, because intact rubber normally absorbs ultrasonic waves, its actual reflected signal will be in the low-intensity range near this threshold (i.e., lower than or equal to the first preset threshold).

[0029] 2. Determination of the second preset threshold (missing / leaking baseline calibration): Using the same simulated test block, the seal is removed or a through-hole defect is artificially created, forming a direct 'metal-air' interface at the flange mating surface. An A-scan is performed using the same instrument parameters to obtain the strongest reflected signal intensity generated when the ultrasonic wave encounters air (according to background technology, the acoustic impedance difference between air and metal is extremely large, resulting in very strong reflection). The high reflected signal intensity value under this severe defect state is set as the 'second preset threshold'.

[0030] 3. Physical significance of the intermediate section (poor sealing effect): When the detected A-scan reflection signal intensity falls between the 'first preset threshold' and the 'second preset threshold', it indicates that the sealing rubber is not completely missing, but its interior may have aged, cracked, or misaligned, leading to increased local gaps. This reduces the rubber's ability to absorb ultrasonic waves, resulting in a significant increase in reflection intensity compared to the intact reference (first preset threshold). The instrument automatically classifies such signals between the two thresholds as 'poor sealing performance'.

[0031] By using the above-mentioned two-end calibration method based on 'intact benchmark' and 'completely missing benchmark', a corresponding judgment threshold database can be quickly established for different types of electrical equipment (such as aluminum / carbon steel / copper flanges of different thicknesses and rubber rings of different materials), thereby achieving objective and accurate classification judgment of sealing status.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs phased array ultrasonic testing technology as its core technique, addressing the challenge of detecting internal rubber sealing materials in large electrical equipment by constructing a physical detection model based on acoustic impedance differences. The principle is that when ultrasonic waves encounter interfaces between different media during propagation, their reflection intensity depends on the acoustic impedance difference between the two media. Electrical equipment casings are typically made of high-density metal, while internal seals are made of low-density rubber. Leaks or damage often involve the introduction of an air layer. Since the acoustic impedance difference between metal and rubber is relatively small, sound waves can partially transmit. However, the acoustic impedance difference between metal and air (or rubber and air) is extremely large, leading to strong reflection of ultrasonic waves at the interface. Based on this principle, this invention fixes multiple phased array probes one by one to an adjustable curvature wedge and abuts against the surface to be tested. A specific focusing mode is established according to the depth of the detection location and the type of material. The excitation time delay of the phased array probes is precisely adjusted to control the beam angle and focusing depth, ensuring accurate focusing on the cross-sectional location of the sealing layer. This technical feature directly enables the accurate identification of the integrity, improper compression, or broken / missing state of sealing materials by capturing and analyzing the intensity and waveform characteristics of reflected waves without disassembling the equipment casing. This effectively solves the technical problem that traditional testing methods require shutdown and disassembly, which damages the equipment structure and has a long testing cycle. It greatly reduces operation and maintenance costs and safety risks, and avoids new hidden dangers caused by secondary assembly.

[0033] Addressing the structural characteristics of large electrical equipment's sealing components, which often involve curved flanges or pipes, this invention develops a probe wedge with a special shape, specifically an adjustable wedge composed of multiple rectangular wedges connected by hinges. In principle, ultrasonic testing demands extremely precise sound beam incident angles and coupling conditions. Traditional rigid wedges struggle to achieve perfect contact with curved surfaces, and minute air gaps between the wedge and the workpiece cause severe sound wave scattering and attenuation, resulting in weak or even lost effective signals. The modular wedge design in this invention allows operators to adjust the hinge overlap width at the connection point according to the pipe radius, changing the gap width of the strip wedges and thus controlling the radius of the wedge's wrap around the curved surface, ensuring a geometrically tight fit with the surface being tested. Combined with the use of a couplant, the strong reflection interference of the interfacial air layer on the sound waves is eliminated, ensuring that ultrasonic energy can be efficiently and vertically transmitted into the workpiece. This design not only significantly improves the sound energy transmittance and detection signal-to-noise ratio, but also enables the detection method to be flexibly adapted to electrical equipment with different pipe diameters. It solves the problems of poor adaptability and unstable signal of existing probes in curved surface detection, and significantly improves the reliability and repeatability of detection results.

[0034] Furthermore, this invention employs multi-mode scanning and database comparison analysis in the data processing and discrimination stages, forming a complete closed-loop verification system. By selecting combined scanning modes such as A-scan and C-scan, and combining them with electronic line scanning or sector scanning techniques, multi-dimensional image information of the sealing cross-section can be obtained. The principle lies in recording waveform characteristics through full-wave or half-wave scanning and comparing them with a pre-established database containing various states such as intact seals, leaks, and defects. For example, an intact seal interface exhibits specific absorption characteristics (such as blue lines in a C-scan image), while defective areas exhibit strong reflection characteristics (such as red lines). This technique of converting complex acoustic signals into intuitive and visible images effectively avoids the subjectivity and errors of human experience-based judgment, enabling inspectors to quickly and accurately locate defects and assess the sealing condition. This not only improves inspection efficiency but also provides scientific and quantitative data support for the condition-based maintenance of electrical equipment, ensuring the long-term safety and stability of equipment operation. In summary, this invention, through the organic combination of principle innovation, hardware improvement, and data analysis methods, achieves efficient and accurate in-situ detection of the rubber seal condition of electrical equipment, demonstrating significant technological advancements. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the adjustable curvature wedge block of the present invention.

[0036] Figure 2 This is a schematic diagram illustrating the operation of the adjustable curvature wedge block of the present invention for in-situ detection of internal seals of aluminum alloy metal flanges.

[0037] Figure 3 The internal seals of the equipment were inspected using a sector scan method across the entire wavelength range, and the seals were found to be intact.

[0038] Figure 4 The internal seals of the equipment were inspected electronically across the entire wavelength range, and the seals were found to be intact.

[0039] Figure 5 The internal seals of the equipment were detected using electronic methods across the entire wavelength, but the sealing performance of the seals was poor.

[0040] Figure 6 To detect the condition of the internal seals of the equipment using electronic full-wavelength detection, some seals are missing.

[0041] Figure 7 The internal seals of the device were tested electronically using half-wavelength detection, and the seals were found to be intact.

[0042] Figure 8 The internal seal of the device was partially missing, and the condition was detected using an electronic half-wavelength method.

[0043] Among them: 1. Strip wedge; 2. Hinge; 11. Probe fixing screw hole; 101. First pipe flange; 102. Second pipe flange; 103. Rubber sealing gasket; 104. Connecting bolt.

[0044] Figure 3-8 The screenshots taken from the testing equipment are used to qualitatively illustrate the technical solution of this invention. Whether the coordinate text is clear or not does not affect the understanding and qualitative description of the technical solution of this invention. Therefore, unclear coordinate text will not be enlarged. Detailed Implementation

[0045] The technical solution will be further described below with reference to the accompanying drawings and specific embodiments to help understand the content of the present invention.

[0046] Example 1 The sealing structure of large power equipment (such as transformers, converter transformers, GIS switchgear, and converter valves) is a core component for sealing insulating media such as SF6 and insulating oil, as well as cooling circulating media. It directly affects the long-term operational reliability of the equipment and the safety of the power grid, making its reliability testing crucial. Traditional seal testing requires disassembling the equipment, which is not only costly and time-consuming, but may also introduce new sealing hazards due to reassembly. Moreover, such equipment is very valuable, and a single downtime can result in losses of hundreds of thousands of yuan.

[0047] Taking the Xinjiang ±500 kV Yimin converter station as an example, the bipolar system has 14 converter transformers. The transformer body is filled with transformer oil as the insulating medium. The main body involves over 700 sealing components of more than 20 different specifications and sizes, with the largest O-ring seal measuring φ339mm / φ8.4mm and the smallest φ30mm / φ4mm. Leakage is prone to occur at the flanges connecting to the main tank, manholes, bushings, coolers, tap changers, CT junction boxes, bellows, oil pumps, oil flow relays, and dehumidifiers. The main cause of leakage is aging of the sealing rubber or improper installation leading to insulating oil leakage. Taking a single phase of a 550kV GIS as an example, there are 183 sealing points with 10 different specifications and sizes, the largest sealing ring measuring φ590.6mm / φ10.3mm and the smallest φ10.6mm / φ1.8mm. The main materials used for sealing components of power transformers are nitrile rubber, fluorosilicone rubber, and acrylic rubber (generally determined according to environmental conditions and technical agreements, with nitrile rubber being the preferred material under normal conditions).

[0048] Numerous gas leakage faults have occurred within the power grid system, primarily due to improper assembly of sealing rings and sealing ring materials that do not meet service temperature requirements. GIS equipment contains 0.4~0.6Mpa SF6, making effective leak sealing difficult once it occurs, posing a significant obstacle to on-site operation and maintenance. Furthermore, the repair of large electrical equipment is highly complex, requiring intricate procedures. Replacement and troubleshooting can only be performed during fixed annual inspection periods, lasting only one to ten days. Moreover, sealing components are hidden inside the equipment, making it impossible to obtain information about them without disassembly. However, disassembling large electrical equipment is extremely difficult; disassembling just one flange could require eight skilled technicians working for over six hours. Therefore, there is an urgent need for an in-situ sealing component flaw detection technology in electrical equipment to accurately determine the location of sealing component failures and enable targeted repairs.

[0049] In-situ non-destructive testing (NDT) technology enables real-time assessment of sealing conditions through non-contact and non-destructive methods, avoiding equipment downtime and significantly reducing maintenance costs, thus demonstrating a strong necessity for its application. Existing NDT methods for large power equipment mainly include X-ray inspection, magnetic particle inspection, and infrared inspection, but they have unavoidable drawbacks. X-ray inspection involves strong electromagnetic radiation, requiring radiation protection during the inspection process; the equipment is too bulky and inconvenient; the testing cost is too high; and the high energy of X-rays makes them ineffective for inspecting low-density materials such as rubber and plastics. Magnetic particle inspection is only suitable for metallic or ferromagnetic materials and cannot inspect rubber components encased inside large electrical equipment. Infrared inspection typically only detects surface or near-surface defects; it is sensitive to material surface emissivity; and environmental factors such as temperature and wind can affect the results.

[0050] like Figure 1 As shown, the present invention provides an adjustable curvature wedge, which includes a plurality of strip wedges 1 that are hinged together to form a track-like structure; the shape of the track-like structure can be adjusted to wrap around curved surfaces of different radii; when the adjustable curvature wedge is used for testing, each strip wedge is connected to an ultrasonic probe.

[0051] The hinge is formed by connecting the strip wedge 1 through multiple hinges 2.

[0052] The strip wedge 1 is rectangular.

[0053] The materials used for the strip-shaped wedge 1 include: plexiglass, epoxy resin, and polystyrene.

[0054] A device for testing the service condition of rubber sealing materials includes: an ultrasonic flaw detector and an adjustable curvature wedge; the adjustable curvature wedge is connected to the probe of the ultrasonic flaw detector.

[0055] like Figure 2As shown, the adjustable curvature wedge of the present invention is used for in-situ testing of the internal seals of aluminum alloy metal flanges. A rubber sealing gasket 103 is provided between the first pipe flange 101 and the second pipe flange 102. A sealing connection is formed by pressing the rubber sealing gasket 103 through the first pipe flange 101 and the second pipe flange 102 with connecting bolts 104. The adjustable curvature wedge of the present invention fits against the outer circumferential surface of the flange. Each strip wedge 1 is provided with a probe fixing screw hole 11 for fixing a phased array ultrasonic probe, and the phased array ultrasonic probe is fixed to each strip wedge 1.

[0056] This invention provides a method for testing the service condition of rubber sealing materials for electrical equipment, the method comprising: Step 1: Establish a focusing mode based on the material and thickness of the equipment part to be inspected, the number of phased array probe elements, etc., and import it into the ultrasonic flaw detector; Step 2: Determine the number of strip wedges in the adjustable curvature wedge block based on the curvature of the large electrical equipment to be tested; Step 3: Apply coupling agent to the probe contact surface of the strip wedge, and fix the phased array probe of the ultrasonic flaw detector to each strip wedge one by one; use the coupling agent to improve the contact surface fit between the wedge and the ultrasonic probe, reduce the reflection of ultrasonic waves by air at the wedge and probe interface, and reduce the impact on the detection results; select an appropriate scanning mode. Step 4: Use tools to remove debris from the test surface and apply coupling agent to the test surface. Then, attach the workpiece contact surface of the adjustable curvature wedge to the test surface. Step 5: Use ultrasound to scan and collect the scan data, and compare it with the database to determine the sealing condition.

[0057] The materials of the equipment parts to be tested include aluminum and aluminum alloys, carbon steel, stainless steel, copper and copper alloys, etc., and the thickness of electrical equipment parts is between 10-500 mm.

[0058] The types of sealing materials used in the internal testing of the equipment components include nitrile rubber, EPDM rubber, fluororubber, silicone rubber, fluorosilicone rubber, and special rubbers. The shapes of the sealing materials include O-rings (interface diameter 1-50 mm), U-rings (lip thickness approximately 0.5-19 mm), V-rings (angle 60°-90°), Y-rings (lip inclination angle 15°-30°), H-rings (cross-sectional height 1-50 mm), and gaskets (thickness 1-50 mm), etc.

[0059] The phased array probe to be used has 8, 16, 24, 32, 60, 128, and 256 elements.

[0060] The types of materials to be used for the wedges include plexiglass, epoxy resin, polystyrene, etc., and the shapes include flat plates (cubes or rectangular flat plates with a thickness of 5-50 mm), triangular prisms (with a thickness of 5-50 mm), arcs, wedges, and special forms.

[0061] like Figure 1 As shown, the adjustable curvature wedge used in this invention consists of multiple rectangular wedges connected by hinges to form a track structure to adapt to different curvatures and shapes. The probe connection position is located in the middle of each wedge and avoids the hinge installation position. The overlap width between the hinge and the strip wedge is adjustable. By changing the installation position of the hinge on the strip wedge, the radius of the curved surface that the wedge can wrap around can be adjusted. Changing the lateral installation position of the hinge on the strip wedge can change the gap between adjacent strip wedges, thereby increasing the maximum curvature of the adjustable curvature wedge and adapting to pipes with different radii.

[0062] The coupling agents to be used include water, machine oil, grease, petroleum jelly, silicone oil, polyvinyl alcohol, paraffin, etc.

[0063] The scanning methods to be used are A-scan, B-scan, and C-scan, with scanning modes including E-scan (electronic line scan), S-scan (sector scan, 10°-75°), and composite scan (E+S). The scanning step is 0.5-5 mm, the excitation frequency is 20-60 kHz PRF, and the refresh rate is greater than or equal to 10 Hz. The scanning wavelengths are full-wave scanning and half-wave scanning. Among them, A-scan, B-scan, and C-scan are common knowledge in the field of ultrasonic nondestructive testing. Their scanning essence is as follows: A-scan displays a one-dimensional waveform diagram of the ultrasonic echo amplitude changing with the sound path (depth); B-scan displays a two-dimensional cross-sectional diagram containing the contour of the detection section and internal echo information; C-scan displays a top-view projection diagram of the scanning trajectory along the workpiece surface, reflecting the echo intensity distribution at a specific depth through color mapping. The essence of E-scan is to achieve parallel movement of the sound beam within the coverage area of ​​the probe array by electronically controlling the activation sequence of different array elements of the phased array probe; the essence of S-scan is to achieve multi-angle deflection of the sound beam within a preset angle range by electronically adjusting the transmission and reception delay laws of different array elements. The essential difference between full-wave scanning and half-wave scanning lies in the detection processing method of the radio frequency signal. Full-wave scanning retains the complete positive and negative half-cycles of the signal to reflect the true phase and spectral characteristics, while half-wave scanning only retains the positive half-cycle to extract the amplitude envelope of the signal.

[0064] The surface contaminants to be tested include oil stains, rust-preventive coatings, etc., and the coupling agents include water, machine oil, grease, petroleum jelly, silicone oil, polyvinyl alcohol, paraffin, etc.

[0065] The specific steps include the following: (1) The equipment to be tested is an aluminum alloy structure with a thickness of 15 mm. Its internal sealing component is a nitrile rubber O-ring with a cross-sectional diameter of 5 mm. An ultrasonic probe with 64 probe elements is selected to perform ultrasonic non-destructive testing. (2) Select a square wedge with a thickness of 10 mm, use machine oil as a coupling agent to eliminate air at the interface between the probe and the wedge, ensure that the two parts fit together completely, and reduce reflection caused by air. (3) Select A+C scan, scan mode: sector scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, full wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply machine oil as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) After the ultrasound penetrates the metal, it will be absorbed at the sealing point (weak reflection intensity in A-scan, blue line appears at the C-scan interface). If the sealing effect is poor, the absorption will be enhanced (stronger reflection intensity in A-scan, yellow line appears at the C-scan interface). If there is a sealing defect, stronger reflection will occur (further enhanced reflection intensity in A-scan, red line appears at the C-scan interface). The test results are as follows: Figure 2 As shown, the seal provides a good internal seal with no risk of leakage.

[0066] This invention can be used to assess the sealing condition of internal seals in large electrical equipment. Compared to previous seal testing methods, which required shutting down and disconnecting the large electrical equipment, disassembling and removing the sealing material, and then performing various key performance tests on the material to obtain a seal condition assessment, this invention can assess the seal condition in situ without disassembly, saving significant manpower, resources, and time. Furthermore, after the seal is installed, the testing method provided by this invention can be used to verify the placement and condition of the seal, preventing damage to the seal due to incorrect placement and subsequent leakage problems.

[0067] Example 2 (1) The equipment to be tested is a carbon steel structure with a thickness of 20 mm. Its internal sealing component is a EPDM rubber O-ring with a cross-sectional diameter of 5 mm. An ultrasonic probe with 64 probe array elements is selected to perform ultrasonic non-destructive testing. (2) Select a trapezoidal wedge with a thickness of 10 mm to avoid the influence of bolts on the ultrasonic probe's positioning. Use grease as a coupling agent to eliminate air at the interface between the probe and the wedge, ensuring that the two parts fit together completely and reducing reflection caused by air. (3) Select A+C scan, scan mode: electronic line scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, full wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply grease as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) Test results are as follows Figure 3 As shown, the seal provides a good internal seal with no risk of leakage.

[0068] Example 3 (1) The equipment to be tested is a copper structure with a thickness of 30 mm. Its internal sealing component is a fluororubber O-ring with a cross-sectional diameter of 10 mm. An ultrasonic probe with 64 probe elements is selected to prepare for ultrasonic non-destructive testing. (2) Select a square wedge with a thickness of 10 mm, use machine oil as a coupling agent to eliminate air at the interface between the probe and the wedge, ensure that the two parts fit together completely, and reduce reflection caused by air. (3) Select A+C scan, scan mode: electronic line scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, full wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply machine oil as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) Test results are as follows Figure 4 As shown, the increased reflection intensity at the sealing interface indicates a risk of leakage.

[0069] Example 4 (1) The equipment to be tested is a copper alloy with a thickness of 10 mm. Its inner sealing component is a fluorosilicone rubber H-ring with a cross-sectional diameter of 8 mm. An ultrasonic probe with 64 probe elements is selected to prepare for ultrasonic non-destructive testing. (2) Select a special type of wedge and use machine oil as a coupling agent to eliminate air at the interface between the probe and the wedge, ensuring that the two parts fit together completely and reducing reflection caused by air. (3) Select A+C scan, scan mode: electronic line scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, full wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply machine oil as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) Test results are as follows Figure 5 As shown, there is a section of the seal with significantly increased reflectivity, indicating a defect in the rubber ring.

[0070] Example 5 (1) The equipment to be tested is a stainless steel structure with a thickness of 50 mm. Its internal sealing component is a fluororubber O-ring with a cross-sectional diameter of 10 mm. An ultrasonic probe with 64 probe elements is selected to perform ultrasonic non-destructive testing. (2) Select a wedge block with a thickness of 20 mm, use grease as a coupling agent to eliminate air at the interface between the probe and the wedge block, ensure that the two parts fit together completely, and reduce reflection caused by air. (3) Select A+C scan, scan mode: electronic line scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, full wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply grease as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) Test results are as follows Figure 6 As shown, a section of the seal exhibits significantly abnormal reflection intensity, indicating that part of the seal is missing.

[0071] Example 6 (1) The equipment to be tested is an aluminum alloy structure with a thickness of 12 mm. Its internal sealing component is a silicone rubber V-ring with an included angle of 75°. An ultrasonic probe with 64 probe array elements is selected to prepare for ultrasonic non-destructive testing. (2) Select a square wedge with a thickness of 10 mm, and use Vaseline as a coupling agent to eliminate air at the interface between the probe and the wedge, so as to ensure that the two parts fit together completely and reduce the reflection caused by air. (3) Select A+C scan, scan mode: electronic line scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, half wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply petroleum jelly as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) Test results are as follows Figure 7 As shown, the seal provides a good internal seal with no risk of leakage.

[0072] Example 7 (1) The equipment to be tested is a carbon steel structure with a thickness of 35 mm. Its internal sealing component is a nitrile rubber U-ring with a lip thickness of about 8 mm. An ultrasonic probe with 64 probe elements is selected to prepare for ultrasonic non-destructive testing. (2) Select a trapezoidal wedge with a thickness of 15 mm, and use machine oil as a coupling agent to eliminate air at the interface between the probe and the wedge, so as to ensure that the two parts fit together completely and reduce the reflection caused by air. (3) Select A+C scan, scan mode is electronic line scan, scan step is 1 mm, excitation frequency is 25 Hz, refresh frequency is set to 20 Hz, half wave scan; (4) Use cleaning tools to remove dust and rust-preventive coating from the surface of the test area, apply machine oil as a coupling agent, and perform phased array ultrasonic non-destructive testing; (5) Test results are as follows Figure 8 As shown, a section of the seal exhibits significantly abnormal reflection intensity, indicating that part of the seal is missing.

[0073] The core breakthrough of this invention, distinguishing it from existing technologies, lies in combining an "adjustable curvature tracked wedge" with a "multi-probe array distributed layout." This structural reconstruction fundamentally changes the operational mode of in-situ inspection of flange seals in large electrical equipment, improving both efficiency and accuracy. Its specific technical effects are reflected in the following aspects: Significant improvements in detection efficiency: Traditional single-probe in-situ scanning is a "serial" operation mode, requiring operators to move a single probe point by point along the flange circumference with extremely small steps (e.g., 0.5-5 mm). For flanges with diameters often hundreds of millimeters (e.g., a φ590 mm flange with a circumference of nearly 1.9 meters), completing a full scan requires a significant amount of time spent on repeated "coupling agent application-adhesion-movement-acquisition" actions. This invention, however, employs a tracked multi-probe parallel structure, using multi-channel (e.g., 200 channels) synchronous excitation to upgrade "single-point line scanning" to "wide-area scanning." Depending on the circumferential angle of the track, typically only 1 to 3 translations along the outer circumference of the flange are needed to achieve 100% data coverage of the entire 360-degree sealing ring. This parallel acquisition mechanism exponentially compresses the single-circumference scanning time, greatly improving the on-site efficiency of in-situ testing, perfectly meeting the stringent time window requirements of extremely short power outage maintenance cycles for large electrical equipment (typically only one to ten days).

[0074] Fundamental improvements in detection accuracy and stability: Traditional manual probe movement is prone to introducing uncontrollable human error. On the one hand, manual movement makes it difficult to maintain a uniform speed, leading to a mismatch between the ultrasonic pulse repetition frequency (PRF) and the mechanical stepping, resulting in spatial sampling rate distortion. On the other hand, the constantly changing force and angle of manual pressure can easily cause slight "tilting" or "twisting" between the wedge and the flange surface, resulting in uneven coupling agent film thickness, which in turn causes ultrasonic beam deflection and energy attenuation. The tracked structure of this invention, through hinged adaptive flange curvature, is equivalent to providing a rigid and conformal track base for all probes. When the track is aligned with the flange, the probes on each strip wedge can maintain an optimal and consistent coupling state. More importantly, the relative spatial position of multiple probes on the track is completely locked by the mechanical structure, completely eliminating the problem of inconsistent stepping distance caused by manual movement, and fundamentally preventing "missed scan blind spots" or "redundant rescans" between adjacent scanning areas. This combination of mechanical spacing and electronic synchronization ensures that the acquired C-scan images have a highly uniform spatial resolution in the circumferential direction, guaranteeing the accuracy of locating and quantitatively assessing minor defects or aging flaws in the seals.

[0075] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention.

Claims

1. An adjustable curvature wedge, characterized in that, It includes multiple interlocking strip wedges forming a track-like structure; the shape of the track-like structure can be adjusted to wrap around curved surfaces of different radii; when the adjustable curvature wedges are used for testing, each strip wedge is connected to an ultrasonic probe.

2. The adjustable curvature wedge block according to claim 1, characterized in that, The hinge is formed by connecting the strip wedge block with multiple hinges.

3. The adjustable curvature wedge block according to claim 1, characterized in that, The strip wedge includes a rectangle.

4. The adjustable curvature wedge block according to claim 1, characterized in that, The materials used for the strip-shaped wedges include: plexiglass, epoxy resin, and polystyrene.

5. A device for testing the service condition of rubber sealing materials, characterized in that, include: An ultrasonic flaw detector and an adjustable curvature wedge according to any one of claims 1-4; the adjustable curvature wedge is connected to the probe of the ultrasonic flaw detector.

6. A method for testing the service condition of rubber sealing materials, characterized in that, The method includes: Establish a focusing mode based on the material, thickness, and number of phased array probe elements of the equipment part to be inspected, and import it into the ultrasonic flaw detector; For the curvature of the test surface at the test location, determine the number of strip wedges in the adjustable curvature wedges as described in any one of claims 1-4; Coupling agent is applied to the probe contact surface of the strip wedge, and the phased array probe of the ultrasonic flaw detector is fixed to each of the strip wedges one by one. Remove debris from the test surface and apply coupling agent to the test surface. Then, attach the workpiece contact surface of the adjustable curvature wedge to the test surface. The sealing material is scanned using ultrasound, and the scan data is collected and compared with a database to determine the sealing condition.

7. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The phased array probe has 8, 16, 24, 32, 60, 128 or 256 elements.

8. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The test area includes the outer circumferential surface of the joint flange.

9. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The material of the test part is one of aluminum and aluminum alloys, carbon steel, stainless steel, copper and copper alloys.

10. A method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The thickness of the test area is between 10 and 500 mm.

11. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The types of sealing materials include nitrile rubber, EPDM rubber, fluororubber, silicone rubber, fluorosilicone rubber, and special rubbers.

12. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The sealing materials include O-rings, U-rings, V-rings, Y-rings, H-rings, and gaskets.

13. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The scanning modes include electronic line scanning, sector scanning, or composite scanning.

14. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The coupling agent includes water, engine oil, butter, petrolatum, silicone oil, polyvinyl alcohol, or paraffin.

15. The method for testing the service condition of a rubber sealing material according to claim 6, characterized in that, The comparison database for distinguishing sealing conditions includes: determining the service status of the sealing material by comparing the waveform characteristics of the scanned data with a pre-stored sealing status database. The service status includes good sealing, poor sealing effect, and missing sealing parts.

16. The method for testing the service condition of a rubber sealing material according to claim 15, characterized in that, The determination of a good seal includes: after the ultrasonic wave penetrates the metal, it is absorbed at the sealing material. If the intensity of the reflected signal of the A-scan of the ultrasonic flaw detector is lower than a first preset threshold, and the C-scan interface displays a preset color line representing the low reflected signal intensity, then the seal is determined to be good.

17. The method for testing the service condition of a rubber sealing material according to claim 15, characterized in that, The determination of poor sealing effect includes: if the intensity of the reflected signal of the A-scan of the ultrasonic flaw detector is higher than the first preset threshold and lower than the second preset threshold, and the C-scan interface displays a preset color line representing a higher reflected signal intensity, then the sealing effect is determined to be poor.

18. The method for testing the service condition of a rubber sealing material according to claim 15, characterized in that, The determination of missing sealing parts includes: if the intensity of the reflected signal of the A-scan of the ultrasonic flaw detector is higher than the second preset threshold, and the C-scan interface displays a preset color line representing the intensity of high reflected signal, then the sealing part is determined to be missing.

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