Hexagonal array eddy current probe

Abstract

The invention discloses a hexagonal array eddy current probe, and belongs to the field of eddy current probes, the hexagonal array eddy current probe comprises a plurality of eddy current detection coils, the detection coils are self-inductance coils, the coil units are the same in size and consistent in parameter, the coils are arranged in an array according to a hexagonal rule, and the distance between the adjacent coils is equal and is smaller than the outer diameter of the coils. According to the invention, through a topological connection mode that one coil is arranged at an interval, a detection blind area right below a single coil is effectively covered and eliminated, and the detection accuracy is improved.

Description

Technical Field

[0001] The present invention relates to an eddy current probe, and more particularly to an array eddy current probe with a hexagonal layout. Background Art

[0002] Eddy current testing is a non-destructive testing method based on the principle of electromagnetic induction, mainly used for detecting defects on the surface and near the surface of metal materials. Traditional array eddy current testing probes form a probe array by arranging multiple eddy current coils in a certain pattern. By reasonably arranging the spacing and arrangement pattern between the probes, the detection information of multiple measurement points can be obtained quickly, greatly improving the detection speed. Common array eddy current probes include forms such as rectangular arrays and staggered arrays, and the combination method between the array coils is relatively single, mostly fixed co-directional probes or independent unit detections, which results in low sensitivity of the array eddy current probe to defects in different directions, making it difficult to achieve precise detection of defects in different directions. Moreover, due to the characteristics of eddy current testing in the central area of the array coils, a detection blind area will be formed, and it is easy to have missed detection phenomena. Summary of the Invention

[0003] The purpose of the present invention is to provide an array eddy current probe with a hexagonal layout to solve the problems that the existing eddy current probes have low sensitivity to defects in different directions, it is difficult to achieve precise detection of defects in different directions, and due to the characteristics of eddy current testing in the central area of the array coils, a detection blind area will be formed and it is easy to have missed detection phenomena.

[0004] To achieve the above purpose, the specific solutions are as follows:

[0005] An array eddy current probe with a hexagonal layout includes a number of eddy current detection coils. The detection coils are all self-inductance coils, each coil unit has the same size and consistent parameters, and the coils are arranged in an array according to the hexagonal rule, and the distance between adjacent coils is equal and less than the outer diameter of the coil.

[0006] Furthermore, different coil connection topologies can be realized through electronic switch switching to form different coil differential pairs.

[0007] Furthermore, the coil connection topology is as follows: the coils are arranged in a hexagonal array. In the hexagonal array arrangement, any one coil can be used as the central coil, and any central coil can respectively form six groups of differential eddy current detection pairs with different directions with the six adjacent coils around it, and each coil is combined with the coil separated by one to form an eddy current detection pair.

[0008] Furthermore, the coil structures, parameters, and winding directions of the coils separated by one are the same.

[0009] In summary, the present invention has the following beneficial effects compared with the prior art:

[0010] Through the topological connection method with one coil interval, the present invention effectively covers and eliminates the detection blind area directly below a single coil, improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0012] Figure 1 Schematic diagram of the array eddy current probe with a hexagonal layout according to the present invention;

[0013] Figure 2 Schematic diagram of various differential combination methods of two coils according to the present invention;

[0014] Figure 3 Schematic diagram of the electromagnetic induction curve of two differential coils according to the present invention.

[0015] Among them, the above-mentioned drawings include the following reference numerals:

[0016] 1. Metal material to be measured; 2. Eddy current detection coil; 3. Electromagnetic induction curve; 4. Eddy current field in the object to be measured. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0018] It should be noted that the terms used herein are only for describing the specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form can also include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0019] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0020] See Figures 1 to 3 As shown, the present invention provides an array eddy current probe with a hexagonal layout. The array eddy current probe is composed of multiple eddy current detection coils. Each coil is a self-inductive coil, which is both an excitation coil and a detection coil. Each coil unit has the same size and consistent parameters. The coils are arranged in an array according to the hexagonal rule. The distance between adjacent coils is equal and less than the outer diameter of the coil to prevent the occurrence of detection blind spots and missed detections. By switching the electronic switch, different coil connection topologies can be achieved, thereby forming different coil differential pairs to achieve high sensitivity to defects in different directions.

[0021] In the hexagonal array arrangement, any one coil can be used as the central coil, and any central coil can respectively form six groups of differential eddy current detection pairs with six adjacent coils around it, with different directions. In actual detection, a sine excitation signal with the same frequency should be applied to the two coils of the differential eddy current detection pair, and the two coils should be connected to the signal extraction circuit to extract the eddy current detection characteristic signal for analysis. As Figure 2 (a) shows a kind of adjacent topological connection method. In the figure, C1 is used as the central coil, and it can respectively form six groups of eddy current detection pair combinations with different directions with the six adjacent coils A1, B2, D2, E1, D1, B1 around it to achieve high-sensitivity detection of defects in different directions on the object to be measured.

[0022] In the above coil combination method, due to the characteristics of the coil electromagnetic induction curve, a detection blind spot will be formed under each coil. Especially when there is no relative movement between the detection probe and the object to be measured, a missed detection phenomenon will occur.

[0023] The second topological connection method of the present invention can effectively eliminate the influence of the detection blind spot under the coil. Each coil can also be combined with the coil separated by one to form a differential eddy current detection pair, thereby eliminating the detection blind spot under the middle coil on the line connecting the two coils. As Figure 2(b) In the shown example, the B1 coil and the D2 coil are topologically combined into an eddy current detection pair, thereby eliminating the detection blind area under the coil C1 on the intermediate connection line. Figure 2 (b) Only one specific example is shown. In specific implementation, similar operations can be performed on each array coil to eliminate the detection blind area under each coil.

[0024] Through the combination of the above topological connection methods, the array eddy current probe with a hexagonal layout provided by the present invention can not only perform high-sensitivity detection on defects in different directions, but also, without relative movement between the probe and the object to be measured, by switching different detection pairs through an electronic switch, static scanning of defects in different directions can be achieved. By combining two coils with one coil interval, the detection blind area under each coil in the static state is eliminated. This design will greatly improve the detection efficiency and accuracy, and is suitable for occasions with complex shapes, inconvenient movement or high-sensitivity non-destructive testing requirements.

[0025] As a preference, when two coils are combined into an eddy current detection pair, since the structures, parameters, and winding directions of the coils are the same, in actual application, when sinusoidal excitation signals with the same frequency are applied to the two coils, the directions of the signals when accessing the two coils are opposite, and an electromagnetic induction curve and eddy current field distribution as shown in Figure 3 will be formed. When the defect direction on the object to be measured is perpendicular to the connection line between the centers of the two coils, since the magnetic permeability of media such as air at the defect is much lower than that of ferromagnetic materials, the direction of the electromagnetic induction curve will be blocked, and then the formation of the eddy current field in the object to be measured will be changed. At this time, the detection sensitivity is the highest and the signal change is the most obvious; when the defect direction is parallel to the connection line between the centers of the two coils, the blocking effect of the defect on the electromagnetic curve will become not obvious, so the signal output change is very small at this time and the detection sensitivity is very low. An array eddy current probe with a hexagonal layout of the present invention can form eddy current fields in six directions through different coil combinations, so as to achieve high-sensitivity identification of defects in different directions.

[0026] As a preference, in the electromagnetic induction curve and eddy current field distribution formed as shown in Figure 3 , in the area directly below a single coil, due to the axisymmetry of the induced magnetic field and the small change in the induced voltage, the output signal is not sensitive to defects, resulting in a detection blind area.

[0027] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An array eddy current probe with a hexagonal layout, characterized in that It includes a number of eddy current detection coils. The detection coils are all self-inductance coils. Each coil unit has the same size and consistent parameters. The coils are arranged in a hexagonal pattern, and the distance between adjacent coils is equal and less than the outer diameter of the coil.

2. The array eddy current probe with a hexagonal layout according to claim 1, characterized in that, By switching the electronic switch, different coil connection topologies can be realized to form different coil differential pairs.

3. The array eddy current probe with a hexagonal layout according to claim 2, characterized in that, The coil connection topology is as follows: the coils are arranged in a hexagonal array. In the hexagonal array arrangement, any coil can be used as the central coil, and any central coil can respectively form six groups of differential eddy current detection pairs with different directions with the six adjacent coils around it. Moreover, each coil is combined with the coil separated by one to form an eddy current detection pair.

4. The array eddy current probe with a hexagonal layout according to claim 3, characterized in that, The coil structures, parameters, and winding directions of the coils separated by one are the same.

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