Crawler-type pulsed eddy current detection device

Abstract

The utility model discloses a crawler-type pulsed eddy current detection device, which relates to the technical field of eddy current detection devices and comprises a shell, a connecting beam, a crawler belt, a crawler belt beam, a driving wheel, a traction sleeve, a first signal bus, a second signal bus and a pulsed eddy current detection instrument. During detection, the crawler belt is attached to the inner wall of the reaction tube of the ultrahigh-pressure tubular reactor, so that the crawler belt can stably, quickly and continuously penetrate through the reaction tube, the detection shell is prevented from being in contact with the wall of the reaction tube, and mechanical scratches caused by excessive friction of the inner wall of the reaction tube during detection are avoided. Meanwhile, the probe adopts a crawler belt structure, so that the probe can stably pass through an uneven metal gully surface, the condition that a sliding wheel is blocked in a pit is avoided, and the accident rate of pipe blockage of the probe is effectively reduced. In addition, the detection coil with a double-U-shaped structure is adopted, so that the detection sensitivity of the pulse eddy current probe on cracks and local corrosion defects is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of eddy current detection devices, in particular to a crawler type pulsed eddy current detection device. Background Art

[0002] Ultrahigh-pressure tubular reactors (hereinafter referred to as reactors) are key core equipment in my country's million-ton-scale ethylene production plants and are widely used. During operation, the reactor's inner wall is subjected to high temperatures and ultrahigh pressure stresses ranging from 100 MPa to 350 MPa. This makes it susceptible to stress corrosion and fatigue damage after long-term service. Therefore, reactors are typically constructed using low-alloy, high-strength, seamless, thick-walled steel pipes with excellent impact toughness and high tensile strength. Furthermore, to improve the reactor's high-pressure and fatigue resistance, the reactor tubes are further treated with autogenous reinforcement technology. However, as the reactor's service life increases, the autogenous residual stress in the reactor tubes relaxes. Once the beneficial autogenous residual stress decreases or disappears, the likelihood of cracking in the reactor tubes during service increases significantly. Localized corrosion is also a significant risk in ultrahigh-pressure tubular reactors, particularly in the reactor tubes used for ethylene polymerization using the EVA process. Acetic acid accumulates easily during the reactor's shutdown phase, leading to the formation of localized corrosion pits. During continued operation under ultrahigh pressure conditions, the tips of the corrosion pits become new sources of stress concentration, potentially causing new cracks. The internal medium component of the reaction tube of the reactor is ethylene, which is flammable and explosive. Once the reaction tube body cracks and causes ethylene to leak and mix into the steam section of the outer jacket pipe, it may cause a serious explosion accident.

[0003] Given this, regular inspections of ultrahigh-pressure tubular reactors are crucial. Nondestructive testing of thick-walled, cylindrical ultrahigh-pressure tubular reactors in service primarily relies on surface inspections, such as industrial endoscopy, magnetic particle testing, penetrant testing, and eddy current testing. Industrial endoscopy is primarily used for macroscopic inspection of the inner surface of ultrahigh-pressure tubular reactors and can only detect surface defects that appear open. In reality, the inner walls of the reactor tubes of in-service reactors are typically coated with a layer of polyethylene powder approximately 1 mm thick when the reactor is shut down. Industrial endoscopy makes it difficult to detect cracks and localized corrosion pits within the reactor tubes. Magnetic particle testing and penetrant testing are generally used to detect surface cracks on the threads of the reactor tube ends and are not suitable for scanning cracks within the reactor tubes. Eddy current testing is currently the preferred method for detecting inner-tube defects in the reactor tubes by petrochemical companies both domestically and internationally. In 2006, BASF of Germany developed a rotating eddy current testing system for evaluating ultrahigh-pressure tubular reactors, which has been proven effective in several international ethylene plants. In recent years, some large-scale petrochemical plants in East and South China have also implemented rotating eddy current testing (SET) on ultra-high-pressure tubular reactors. While SET can detect cracks and small areas of localized corrosion, it requires the probe to maintain close contact with the inner wall of the reactor tube and continuously rotate 360° during the scanning process. This inevitably causes some scratching of the reactor tube wall and can easily damage the probe. For the owners, mechanical scratching of the reactor tube wall during testing is unacceptable, making the exploration of new non-destructive testing methods of great significance.

[0004] Pulsed eddy current testing (PEC) is a new electromagnetic nondestructive testing (NDT) technology that has gained increasing popularity in recent years. Unlike conventional eddy current testing (EDC), it uses a pulsed square wave as an excitation source, offering advantages such as a wide spectrum and high penetration. Therefore, PEC offers the advantage of effectively detecting defects even under high lift-off conditions. Currently, the probes used for PEC testing of ultra-high-pressure tubular reactors are primarily single-function, through-hole probes. These probes typically consist of a polyester plastic, stainless steel, or aluminum alloy housing, and a built-in detection coil. Inspectors first insert the probe into the reactor tube and then drag the probe through the tube by dragging a protective sleeve to scan the tube, thereby verifying the integrity of the tube. This approach can easily cause mechanical scratches on the inner tube wall and damage the probe housing, further damaging the detection coil structure. While a sliding wheel design with an external housing is currently used to prevent excessive friction on the inner tube wall, actual operation has also shown that the sliding wheel often becomes stuck when passing over localized pitting and corrosion, leading to probe blockage. Utility Model Content

[0005] The purpose of the present utility model is to solve at least one of the technical problems existing in the prior art and to provide a track-type pulsed eddy current detection device, which can enable the detection device to pass smoothly, quickly and continuously in the reaction tube, effectively reducing the probability of excessive friction between the detection device shell and the reaction tube, resulting in mechanical damage and probe blockage.

[0006] The utility model provides a crawler-type pulse eddy current detection device, comprising a shell, a connecting beam, a crawler, a crawler beam, a drive wheel, a traction sleeve, a first signal bus, a second signal bus, and a pulse eddy current detection instrument. The cross section of the shell is a rounded rectangle, and at least three groups of supports are provided circumferentially of the shell, each of the supports is connected to the crawler beam through the connecting beam, two pairs of drive wheels are provided on both sides of the crawler beam, and the crawler is wound around the drive wheel; a front end cover and a rear end cover are respectively provided at both ends of the shell, the front end cover and the rear end cover are detachably connected to the shell, and a threaded joint is provided on the front end cover. The traction sleeve is connected to the front end cover through the threaded joint; two detection coils are provided in the shell, and the detection coils include a U-shaped magnetic core excitation coil and two groups of receiving coils, the U-shaped magnetic core excitation coil is connected to a signal excitation line, and the receiving coil is connected to a signal receiving line, the signal excitation line and the signal receiving line on one group of detection coils are centrally connected to the first signal bus, and the signal excitation line and the signal receiving line on the other group of detection coils are centrally connected to the second signal bus, and the first signal bus and the second signal bus are connected to the pulsed eddy current detection instrument through the traction sleeve.

[0007] A crawler-type pulsed eddy current detection device according to an embodiment of the present utility model has at least the following beneficial effects: during the detection process, the detection personnel can control the detection device to perform a scanning movement inside the reaction tube by dragging the protective traction sleeve. During the detection, the crawler is fitted with the inner wall of the reaction tube of the ultra-high pressure tubular reactor, which can achieve smooth, rapid and continuous passage through the reaction tube, avoiding contact between the detection device shell and the reaction tube wall, and avoiding excessive friction and mechanical scratches on the inner wall of the reaction tube during detection. At the same time, the probe adopts a crawler structure, which can pass smoothly on the uneven metal groove surface, avoiding the situation where the sliding wheel is stuck in the pit, and effectively reducing the probe blockage accident rate. In addition, the utility model adopts a double U-shaped detection coil, which improves the detection sensitivity of the pulse eddy current probe for cracks and local corrosion defects.

[0008] According to the tracked pulsed eddy current testing device described in the utility model, the model of the pulsed eddy current testing instrument is CHPEC-02.

[0009] According to the track-type pulsed eddy current detection device described in the utility model, the track is an anti-static rubber track.

[0010] According to the tracked pulsed eddy current detection device described in the utility model, the traction sleeve is a stainless steel wire reinforced polyethylene tube.

[0011] According to the tracked pulsed eddy current detection device described in the utility model, the connecting line between each pair of the supports on the outer periphery of the shell is parallel to the central axis of the shell.

[0012] According to the track-type pulsed eddy current detection device described in the utility model, the distance between the center line of the U-shaped magnetic core excitation coil and the center of the receiving coil is 15 mm to 25 mm.

[0013] According to the track-type pulsed eddy current detection device described in the utility model, the maximum height ratio of the U-shaped magnetic core excitation coil and the receiving coil is 7:5.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0016] Figure 1 This is a schematic structural diagram of a preferred embodiment of the present utility model;

[0017] Figure 2 This is a left view of a preferred embodiment of the utility model;

[0018] Figure 3 This is a cross-sectional view of a preferred embodiment of the utility model;

[0019] Figure 4 This is a schematic diagram of the three-dimensional structure of the detection coil of a preferred embodiment of the utility model;

[0020] Figure 5 This is a left view of the detection coil of the preferred embodiment of the utility model;

[0021] Figure 6 This is a plan view of the connecting beam structure of a preferred embodiment of the present utility model.

[0022] Reference numerals:

[0023] 01 Pulsed eddy current testing instrument, 02 Reaction tube; 101 Support, 102 Front cover, 103 Threaded joint, 104 Rear cover, 2 Connecting beam, 3 Track, 4 Track beam, 5 Drive wheel, 6 Traction sleeve, 7 First signal bus, 8 Second signal bus, 9 U-shaped magnetic core excitation coil, 10 Receiving coil, 11 Signal excitation line, 12 Signal receiving line DETAILED DESCRIPTION

[0024] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0026] In the description of this utility model, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0027] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0028] Reference Figures 1 to 6 A tracked pulsed eddy current testing device includes: a housing 1, a connecting beam 2, a track 3, a track beam 4, drive wheels 5, a traction sleeve 6, a first signal bus 7, a second signal bus 8, and a pulsed eddy current testing instrument 01. The housing 1 has a rounded rectangular cross-section. At least three sets of supports 101 are circumferentially arranged around the housing 1. Each support 101 is connected to the track beam 4 via a connecting beam 2. Two pairs of drive wheels 5 are provided on either side of the track beam 4. The track 3 is wound around the drive wheels 5.

[0029] The housing 1 is provided with a front cover 102 and a rear cover 104 at both ends. The front cover 102 and the rear cover 104 are detachably connected to the housing 1. The front cover 102 is provided with a threaded joint 103. The traction sleeve 6 is connected to the front cover 102 via the threaded joint 103.

[0030] Two detection coils are provided in the housing 1. The detection coils include a U-shaped magnetic core excitation coil 9 and two groups of receiving coils 10. The U-shaped magnetic core excitation coil 9 is connected to a signal excitation line 11. The receiving coil 10 is connected to a signal receiving line 12. The signal excitation line 11 and the signal receiving line 12 on one group of detection coils are centrally connected to a first signal bus 7. The signal excitation line 11 and the signal receiving line 12 on another group of detection coils are centrally connected to a second signal bus 8. The first signal bus 7 and the second signal bus 8 are connected to the pulsed eddy current detection instrument 01 through a traction sleeve 6.

[0031] It is understandable that during the detection process, the detection personnel can control the detection device to perform a scanning movement inside the reaction tube by dragging the protective traction sleeve 6. During the detection, the crawler 3 is fitted with the inner wall of the reaction tube of the ultra-high pressure tubular reactor, which can achieve a smooth, fast and continuous passage through the reaction tube, avoiding contact between the detection device shell and the reaction tube wall, and avoiding excessive friction and mechanical scratches on the inner wall of the reaction tube during detection. At the same time, the probe adopts a crawler structure, which can pass smoothly on the uneven metal groove surface, avoiding the situation where the sliding wheel is stuck in the pit, and effectively reducing the probe blockage accident rate. In addition, the utility model adopts a double U-shaped detection coil, which improves the detection sensitivity of the pulse eddy current probe for cracks and local corrosion defects.

[0032] It is worth noting that in the embodiment of the present invention, the housing 1 is provided with two detachable end cover parts at the front and rear ends. One end of the front portion of the housing 1 is provided with a front end cover 102 with a threaded joint 103 in the center. The traction sleeve 6 is screwed and fixed to the front end cover 102 through the threaded joint 103. One end of the rear portion of the housing 1 is provided with a detachable rear end cover 104 (see FIG. Figure 1 ), the outer periphery of the shell 1 is equipped with three pairs of ladder-shaped supports 101 through 3D printing integrated molding technology. The connection line between each pair of supports 101 is parallel to the central axis of the shell 1. Each support 101 is fixed to the connecting beam 2 through bolts and nuts. The connecting beam 2 is screwed and fixed to the threaded interface at the bottom of the crawler beam 4 through the top threaded joint. Two pairs of driving wheels 5 are installed at both ends of the crawler beam 4. The outer side of the driving wheel 5 is equipped with a crawler 3 (see Figure 2 Two detection coils are fixed to the two ends of the housing 1 by heat-melting welding (see Figure 3 ), the detection coil is composed of a U-shaped magnetic core excitation coil 9 and two receiving coils 10 (see Figure 4 and Figure 5 The signal excitation line 11 and the signal receiving line 12 on the detection coil installed on the upper side of the housing 1 are centrally connected to the first signal bus 7, and the signal excitation line 11 and the signal receiving line 12 on the detection coil installed on the lower side of the housing 1 are centrally connected to the second signal bus 8. The first signal bus 7 and the second signal bus 8 pass through the traction sleeve 6 and are connected to the pulsed eddy current detection instrument 01 port (see Figure 1 ).

[0033] It should be noted that, in some embodiments of the present invention, the detection coil is composed of a U-shaped magnetic core excitation coil 9 and two circular receiving coils 10 (see Figure 4 and Figure 5 ), after experimental verification, the distance between the center line of the U-shaped magnetic core excitation coil 9 and the center of the receiving coils 10 on both sides is set to: 15mm-25mm, and the maximum height ratio of the U-shaped magnetic core excitation coil 9 and the receiving coil 10 is set to: 7:5, then the detection sensitivity reaches the best. The outside of the U-shaped magnetic core excitation coil 9 is wound with high-quality copper enameled wire with a wire diameter of 1.0mm-1.4mm, and a total of 120 turns. The receiving coil 10 uses high-quality copper enameled wire with a wire diameter of 0.18mm-0.24mm, and a total of 300 turns. The U-shaped magnetic core excitation coil 9 and the receiving coil 10 need to be glued and fixed for each turn. The detection coils at the two locations are connected to the pulse eddy current detection instrument 01 (CHPEC-02 model) through the first signal bus 7 and the second signal bus 8 respectively through the traction sleeve 6 (see Figure 1 ).

[0034] Furthermore, in an embodiment of the present invention, the model of the pulsed eddy current testing instrument 01 is CHPEC-02.

[0035] Furthermore, in an embodiment of the present invention, the track 3 is an anti-static rubber track.

[0036] It is understandable that the anti-static track can prevent static electricity from being generated by the contact between the track 3 and the pipe wall during the detection process.

[0037] Furthermore, in an embodiment of the present invention, the traction sleeve 6 is a stainless steel wire reinforced polyethylene tube.

[0038] Furthermore, in the embodiment of the present invention, the line connecting each pair of supports 101 on the outer periphery of the housing 1 is parallel to the central axis of the housing 1 .

[0039] Furthermore, in the embodiment of the present invention, the distance between the center line of the U-shaped magnetic core excitation coil 9 and the center line of the receiving coil 10 is 15 mm to 25 mm.

[0040] Furthermore, in the embodiment of the present invention, the maximum height ratio of the U-shaped magnetic core excitation coil 9 to the receiving coil 10 is 7:5.

[0041] In some embodiments of the present invention, the pulsed eddy current testing instrument 01 is model CHPEC-02. The housing 1, support 101, front cover 102, threaded joint 103, rear cover 104, connecting beam 2, track beam 3, and drive wheel 5 are made of POM engineering plastic. The magnetic core of the U-shaped magnetic core excitation coil 9 is made of ferrite, and the circular frame of the receiving coil 10 is made of PP plastic.

[0042] When the utility model is used, the reaction tube 02 of the ultra-high pressure tubular reactor to be inspected is first cleaned with high-pressure water. After the cleaning is completed, the polyethylene powder accumulation inside the reaction tube 02 is observed with an endoscope. When it is confirmed that there is no excess polyethylene powder blocking the probe, a scan can be performed. The six tracks 3 outside the device housing 1 of the detection device are all in supporting contact with the inner wall surface of the reaction tube 02 of the ultra-high pressure tubular reactor (see Figure 3 By controlling the pulling sleeve 6 through the inner wall of the ultrahigh-pressure tubular reactor tube 02, rapid detection of lateral cracks and localized corrosion pits on the inner wall of the reaction tube 02 can be achieved. During use, the overall stepping speed must be controlled within 250 mm / s. At the same time, the voltage amplitude curve of the pulsed eddy current imaging display should be carefully observed. If an abnormal amplitude signal is found, comprehensive confirmation of the abnormal amplitude signal should be carried out using an endoscope or rotating eddy current testing method.

[0043] The present invention enables smooth and rapid preliminary detection of open, near-surface, or subsurface crack defects on the inner surface of the reaction tube 02 of an in-service ultra-high-pressure tubular reactor. Compared to rotating eddy current testing and conventional absolute pulsed eddy current internal testing devices, it can rapidly detect subsurface crack defects with a length of 10 mm and a depth of 12 mm on the inner surface of the reaction tube 02, increasing detection efficiency by nearly 1.5 times. Furthermore, the present invention features smooth and rapid penetration of metal surfaces with localized pits. Its crawler structure effectively reduces the risk of probe blockage and quality accidents. It also ensures that the inner wall surface of the tested reaction tube 02 will not be mechanically scratched during testing. The invention offers a range of advantages, including high detection sensitivity, compact size and weight, and ease of installation and portability.

[0044] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A crawler-type pulsed eddy current testing device, characterized in that: include: A shell (1), a connecting beam (2), a crawler (3), a crawler beam (4), a driving wheel (5), a traction sleeve (6), a first signal bus (7), a second signal bus (8), and a pulsed eddy current detection instrument (01); the shell (1) has a rounded rectangular cross section; the shell (1) is circumferentially provided with at least three groups of supports (101); each of the supports (101) is connected to the crawler beam (4) via the connecting beam (2); two pairs of driving wheels (5) are provided on both sides of the crawler beam (4); and the crawler (3) is wound around the driving wheels (5); A front end cover (102) and a rear end cover (104) are respectively provided at both ends of the housing (1); the front end cover (102) and the rear end cover (104) are detachably connected to the housing (1); a threaded joint (103) is provided on the front end cover (102); and the traction sleeve (6) is connected to the front end cover (102) via the threaded joint (103); Two detection coils are provided in the shell (1), and the detection coils include a U-shaped magnetic core excitation coil (9) and two groups of receiving coils (10). The U-shaped magnetic core excitation coil (9) is connected to a signal excitation line (11), and the receiving coil (10) is connected to a signal receiving line (12). The signal excitation line (11) and the signal receiving line (12) on one group of detection coils are centrally connected to the first signal bus (7), and the signal excitation line (11) and the signal receiving line (12) on the other group of detection coils are centrally connected to the second signal bus (8). The first signal bus (7) and the second signal bus (8) are connected to the pulsed eddy current detection instrument (01) through the traction sleeve (6).

2. A crawler-type pulsed eddy current testing device according to claim 1, characterized in that: The model of the pulsed eddy current testing instrument (01) is CHPEC-02.

3. The crawler-type pulsed eddy current testing device according to claim 1, characterized in that: The crawler (3) is an antistatic rubber crawler.

4. The crawler-type pulsed eddy current testing device according to claim 1, characterized in that: The traction sleeve (6) is a stainless steel wire reinforced polyethylene tube.

5. The crawler-type pulsed eddy current testing device according to claim 1, characterized in that: The connecting line between each pair of the supports (101) on the outer periphery of the shell (1) is parallel to the central axis of the shell (1).

6. The crawler-type pulsed eddy current testing device according to claim 1, characterized in that: The distance between the center line of the U-shaped magnetic core excitation coil (9) and the center of the receiving coil (10) is 15 mm to 25 mm.

7. The crawler-type pulsed eddy current testing device according to claim 1, characterized in that: The maximum height ratio of the U-shaped magnetic core excitation coil (9) to the receiving coil (10) is 7:5.

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