Eddy current sensor array and eddy current sensor

Abstract

The utility model discloses an eddy current transducer array and an eddy current transducer, belonging to the eddy current transducer technology field, comprising a second coil and at least three first coils, the adjacent first coils are arranged at intervals, and the placing positions of all the first coils are connected to form a closed curve. The second coil is arranged at the center of a formed closed curve, the maximum distance between the second coil and the first coil is L1, the maximum distance that the first coil and the second coil can be coupled is L1 ', the maximum distance between the adjacent first coils is L2, the maximum distance that the adjacent first coils can be coupled is L2', L1 < = L1 ', L2 < = L2', and L2 < = L2 '. The first coils and the second coils as well as the adjacent first coils can be coupled, so that the spatial resolution of the eddy-current sensor array and the eddy-current sensor is improved, and the eddy-current sensor array and the eddy-current sensor can be applied under the lift-off of not more than 5mm.

Description

Technical Field

[0001] The utility model relates to the technical field of eddy current sensors, in particular to an eddy current sensor array and an eddy current sensor. Background Art

[0002] Chlor-alkali chemical industry is one of the basic chemical industries. Affected by complex environmental factors such as stray current, brine solution, hydrochloric acid, chlorine, hypochlorous acid, and caustic soda in chlor-alkali plants, production equipment is extremely prone to stress corrosion cracking damage behavior. And because the combination of alkaline ions and metal ions will produce salt scale, cracks are mostly located on the surface of the equipment under the scale, making the cracks more and more concealed. Eddy current testing is a widely used non-destructive testing technology, known for its ability to identify cracks on the inner surface and under the surface of equipment. This technology has the characteristics of non-destructive, non-invasive and low cost, can be used to provide immediate and real-time feedback, and eddy current testing does not require surface treatment, which can simplify the inspection process.

[0003] The spatial resolution (accuracy) of an eddy current sensor is affected by lift-off (the gap between the sample and the sensor). Usually, the signal size and spatial resolution of eddy current testing will decrease with the increase of lift-off. In the case of higher lift-off, it will be difficult to detect closely arranged cracks. Therefore, in order to maintain a high spatial resolution, the prior art needs to control the lift-off distance within a very small range, usually within 1 mm. However, during track inspection, maintaining a very low lift-off distance may increase the risk of sensor damage or track surface wear.

[0004] Therefore, how to design an eddy current sensor to improve the spatial resolution so that it can be applied under a lift-off of no more than 5 mm is a technical problem that those skilled in the art need to solve urgently. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an eddy current sensor array and an eddy current sensor aiming at the defects and deficiencies in the prior art, to improve the spatial resolution, so that the eddy current sensor array and the eddy current sensor can be applied under a lift-off of no more than 5 mm.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is:

[0007] The present utility model provides an eddy current sensor array, which includes a second coil and at least three first coils. The adjacent first coils are arranged at intervals, and connecting the placement positions of all the first coils can form a closed curve. The second coil is placed at the center of the formed closed curve. The maximum distance between the second coil and the first coil is L1, the maximum distance at which the first coil and the second coil can be coupled is L1', the maximum distance between adjacent first coils is L2, and the maximum distance at which adjacent first coils can be coupled is L2'. L1 ≤ L1' and L2 ≤ L2'.

[0008] Preferably, both the first coil and the second coil can be used as both an excitation coil and a receiving coil.

[0009] Preferably, the closed curve formed by connecting the placement positions of all the first coils is a circle.

[0010] Preferably, the intervals between adjacent first coils are uniform.

[0011] Preferably, the distance between adjacent first coils ranges from 1.5 to 2.5 mm.

[0012] Preferably, the distance between the first coil and the second coil ranges from 2 to 4 mm.

[0013] Preferably, iron cores are inserted into both the first coil and the second coil.

[0014] Preferably, the first coil and the second coil have the same structure.

[0015] The present utility model also provides an eddy current sensor, which includes a housing and the eddy current sensor array, and the eddy current sensor array is placed inside the housing.

[0016] The present utility model has achieved the following technical effects compared with the prior art:

[0017] 1. By setting that the maximum distance between the first coil and the second coil is not greater than the maximum distance at which magnetic coupling can be generated between the first coil and the second coil, and setting that the maximum distance between adjacent first coils is not greater than the maximum distance at which magnetic coupling can be generated between adjacent first coils, magnetic coupling can be generated between the first coil and the second coil in the eddy current sensor array, as well as between adjacent first coils, enhancing the magnetic field interaction between the first coil and the second coil and between adjacent first coils, thereby improving the spatial resolution of the eddy current sensor array, enabling the eddy current sensor array and the eddy current sensor to be applied at a lift-off of no more than 5 mm to reduce the risk of wear of the sensor or the track surface.

[0018] Other technical solutions of the present utility model have achieved the following technical effects compared with the prior art:

[0019] 2. By providing both the first coil and the second coil, the present utility model can serve as both an excitation coil and a receiving coil. When in use, all the first coils and second coils can be sequentially used as excitation coils, and the remaining coils can be used as receiving coils, thereby achieving a comprehensive detection of defects at different depths in the measured area of the component, improving the detection efficiency and comprehensiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is an axonometric structural schematic diagram of an eddy current sensor array in some embodiments;

[0022] Figure 2 It is a top view structural schematic diagram of an eddy current sensor array in some embodiments;

[0023] Figure 3 It is a front view structural schematic diagram of an eddy current sensor in some embodiments.

[0024] Among them, 1. First coil; 2. Second coil; 3. Iron core; 4. Housing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present utility model.

[0026] To make the above objects, features, and advantages of the present utility model more obvious and understandable, the present utility model will be further described in detail below with reference to the drawings and specific embodiments.

[0027] Such as Figures 1 to 2As shown in the figure, the present utility model provides an eddy current sensor array, which includes a second coil 2 and at least three first coils 1. The adjacent first coils 1 are arranged at intervals, and connecting the placement positions of all the first coils 1 can form a closed curve. The second coil 2 is placed at the center of the formed closed curve. The maximum distance between the second coil 2 and the first coil 1 is L1, the maximum distance at which the first coil 1 and the second coil 2 can be coupled is L1', the maximum distance between adjacent first coils 1 is L2, and the maximum distance at which adjacent first coils 1 can be coupled is L2'. L1 ≤ L1', L2 ≤ L2', so that magnetic coupling can be generated between the first coil 1 and the second coil 2 and between adjacent first coils 1, enhancing the magnetic field interaction between the first coil 1 and the second coil 2 and between adjacent first coils 1, thereby improving the spatial resolution of the eddy current sensor array.

[0028] Due to the different positions of the excitation coils, the coupling degrees in the regions between different coils are also different. Therefore, in some embodiments, both the first coil 1 and the second coil 2 can be used as both the excitation coil and the receiving coil, so that the eddy current sensor array can comprehensively detect the component to be measured. In addition, since the area covered by one detection (i.e., the area enclosed by the closed curve formed by connecting the placement positions of all the first coils 1) is larger than the coverage area of a single pair of coils (where a single pair of coils refers to a pair of coils composed of an excitation coil and a receiving coil), the eddy current sensor array of the present application can also increase the area of a single detection and improve the working efficiency.

[0029] Among them, the closed curve formed by connecting the placement positions of all the first coils 1 can be a square, a rectangle, an ellipse, a circle, etc. In some embodiments, the closed curve formed by connecting the placement positions of all the first coils 1 is a circle, so that the distances between the second coil 2 and all the first coils 1 are equal, and the intervals between adjacent first coils 1 are uniform, so that the eddy current sensor array has relatively uniform sensitivity in each region, facilitating the detection of cracks in different directions. In some embodiments, the distance between adjacent first coils 1 ranges from 1.5 to 2.5 mm, and the distance between the first coil 1 and the second coil 2 ranges from 2 to 4 mm.

[0030] In order to enhance the magnetic flux density generated by the coils, iron cores 3 are inserted into both the first coil 1 and the second coil 2. For the convenience of design and manufacture, the structures of the first coil 1 and the second coil 2 are set to be the same. In some embodiments, both the first coil 1 and the second coil 2 are wound with conductive metal wires with a wire diameter of 0.05 mm. The total number of turns of each first coil 1 and the second coil 2 is 200 turns, the outer diameter is 1.4 mm, the inner diameter is 0.8 mm, the length of the wound coil is 2.4 mm, and the length of the iron core 3 inserted into the coil is 7.5 mm, and the diameter is 0.7 mm.

[0031] In some embodiments, an eddy current sensor array includes nine coils. The second coil 2 in the middle is surrounded by the ninth coil, and the first coils 1 on the periphery are sequentially called coil 1, coil 2, coil 3... coil 8 in a clockwise direction. During measurement, the nine coils are sequentially used as excitation coils to generate an electromagnetic field, and the remaining eight coils are used as receiving coils to generate induced voltages. Independent measurement values (i.e., mutual impedances) are recorded for each measurement and analyzed. That is, when coil 9 is used as the excitation coil, the measurement values of coils 1, 2... coil 8 as receiving coils are collected; when coil 1 is used as the excitation coil, the measurement values of coils 2, 3... coil 9 as receiving coils are collected; when coil 2 is used as the excitation coil, the measurement values of coils 1, 3... coil 9 as receiving coils are collected... and so on. That is, the same measurement component is detected nine times to obtain (9×8) / 2 = 36 independent measurement values. When coil 1 is used as the excitation coil and coil 2 is used as the receiving coil, the eddy current sensor array can measure defects at a relatively shallow position below the area between coil 1 and coil 2; when coil 1 is used as the excitation coil and coil 3 is used as the receiving coil, due to the coupling between coil 1 and coil 2 and the coupling between coil 2 and coil 3, the spatial resolution of the area between coil 1 and coil 3 is improved, so that defects deeper than the area where coil 1 and coil 2 are located can be detected. And so on. By sequentially using different coils as excitation coils and the remaining coils as receiving coils, defects at different depths in the measured area of the component can be detected, improving the detection efficiency and comprehensiveness. In some embodiments, the first coil 1 or the second coil 2 is excited by a sinusoidal alternating current with an amplitude of 5 mA and a frequency of 200 kHz.

[0032] As Figure 3 shown, the present utility model further includes an eddy current sensor, which includes a housing 4 and an eddy current sensor array. The eddy current sensor array is disposed inside the housing 4.

[0033] It should be noted that for those skilled in the art, it is obvious that the present utility model is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present utility model, and any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. An eddy current sensor array, characterized in that: The invention comprises a second coil and at least three first coils, wherein adjacent first coils are arranged at intervals, and the placement positions of all the first coils are connected to form a closed curve, and the second coil is placed at the center of the formed closed curve, the maximum distance between the second coil and the first coil is L1, the maximum distance that the first coil and the second coil can be coupled is L1', the maximum distance between adjacent first coils is L2, the maximum distance that adjacent first coils can be coupled is L2', L1≤L1', L2≤L2'.

2. The eddy current sensor array according to claim 1, characterized in that: The first coil and the second coil can both be used as an excitation coil and a receiving coil.

3. The eddy current sensor array according to claim 2, characterized in that: The closed curve formed by connecting the placement positions of all the first coils is a circle.

4. The eddy current sensor array according to claim 3, characterized in that: The intervals between adjacent first coils are uniform.

5. The eddy current sensor array according to claim 4, characterized in that: The distance between adjacent first coils ranges from 1.5 to 2.5 mm.

6. The eddy current sensor array according to claim 5, characterized in that: The distance between the first coil and the second coil ranges from 2 to 4 mm.

7. The eddy current sensor array according to claim 6, characterized in that: An iron core is inserted into each of the first coil and the second coil.

8. The eddy current sensor array according to claim 7, characterized in that: The first coil and the second coil have the same structure.

9. An eddy current sensor, characterized in that: The invention comprises a shell and an eddy current sensor array as claimed in any one of claims 1 to 8, wherein the eddy current sensor array is arranged inside the shell.

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