A device for reducing the end effect of ferromagnetic tube and rod eddy current detection

Abstract

The present invention discloses a device for reducing the end effect of eddy current detection of ferromagnetic tubes and rods, a magnetic saturation device (2) with a central channel (3) for eddy current detection of long strip metal tubes and rods (1), comprising a magnetizing coil (21), a guide sleeve (22) and a detection probe (23), characterized in that the guide sleeve (22) is set as a hollow cylindrical structure made of magnetic conductive material, the magnetizing coil (21) is set at the periphery of the guide sleeve (22), the two magnetizing coils (21) and the two guide sleeves (22) form a group of symmetrical arrangements, and the middle detection probe (23) is set in a group of magnetizing coils (21) and guide sleeves (22). The present invention concentrates the magnetization of the metal tube and rod to be detected at the middle part closer to the detection probe without changing the ampere-turns of the magnetic saturation coil, reduces the end blind area that cannot be fully magnetized, and realizes detection in a wider range.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, in particular to electromagnetic eddy current testing technology for metal pipes and rods, and in particular to a device for reducing the end effect of eddy current testing of ferromagnetic pipes and rods. Background Art

[0002] In the magnetic saturation eddy current testing of steel pipes or rods, as shown in the attached Figure 1 As shown in the detection device diagram, since the steel tube rod (1) is in the shape of a long strip, the mobile detection is generally performed by moving the steel tube rod (1) through the channel (3) of the magnetic saturation device (2). Figure 2 As shown in the schematic diagram of the internal structure of the detection device, during the detection process, the steel pipe rod (1) needs to be magnetized, which is generally composed of two sets of symmetrically arranged magnetizing coils (21) and a magnetic conductive guide sleeve (22) as shown in the figure, and the detection probe (23) is arranged between the coil (21) and the guide sleeve (22).

[0003] During the detection process, the moving steel pipe rod (1) slowly passes through the probe, and the magnetic saturation device magnetizes the steel pipe rod. As can be seen from the figure, there is a blind area A at the end of the pipe rod that cannot be fully magnetized at the beginning, resulting in the end blind area being unable to be accurately detected. Especially for large-diameter steel pipes, in order to obtain sufficient magnetization capacity, the ampere-turns and current intensity of the magnetic saturation device need to be increased exponentially, which not only makes the instrument bulky, but also the temperature caused by the heat loss of the magnetizing coil increases significantly, which will affect the current intensity, making it difficult to reach the design value required for detection, and unable to achieve effective detection. The end blind area has always been a problem that is difficult to solve.

[0004] In addition, as the number of turns of the magnetizing coil increases, the instrument becomes bulky, the length of the guide sleeve must be lengthened, and the long steel pipe rod has a certain curvature or defects. A larger gap is required to allow the straight magnetic saturation device guide sleeve to pass through. A large gap will inevitably increase the magnetic resistance, weakening the magnetization ability, which is not conducive to accurate detection.

[0005] In view of the above shortcomings, the present invention adopts the following technical solutions. Summary of the invention

[0006] The purpose of the present invention is to provide a device for reducing the end effect of ferromagnetic tube and rod eddy current detection, and the disclosed technical solution is as follows:

[0007] A device for reducing the end effect of ferromagnetic tube and rod eddy current detection, a magnetic saturation device (2) with a central channel (3) for eddy current detection of a long strip metal tube and rod (1), comprising a magnetizing coil (21), a guide sleeve (22) and a detection probe (23), characterized in that the guide sleeve (22) is arranged as a hollow cylindrical structure made of a magnetic conductive material, the magnetizing coil (21) is arranged on the periphery of the guide sleeve (22), the two magnetizing coils (21) and the two guide sleeves (22) form a group arranged symmetrically, and the detection probe (23) is arranged in the middle of the group of magnetizing coils (21) and the guide sleeve (22),

[0008] The outer diameter of the guide sleeve (22) is set to a cylindrical structure with the same diameter, and the hollow inner diameter of the guide sleeve (22) is set to a plurality of structures with different diameters, so as to form a group of magnetizing coils (21) and the guide sleeve (22) having a thickness greater than that of the two side edges at a portion close to the middle detection probe (23).

[0009] The ratio of the length of the hollow inner diameter large diameter D1 part to the length of the small diameter D2 part of the guide sleeve (22) is between 1:2 and 2:1. When the guide sleeve (22) is made of pure iron with good magnetic conductivity, the ratio of the length of the hollow inner diameter large diameter D1 part to the length of the small diameter D2 part is set to 1:1.

[0010] Further, a single guide sleeve (22) is configured as a cylinder (221) with a large diameter and a large height and a cylinder (222) with a small diameter and a small height, which are sleeved to form a structure in which one end is aligned. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the part close to the detection probe (23) in the middle of the two guide sleeves (22) is greater than the two side edges. Wherein, a single guide sleeve (22) is formed by a plurality of hollow sleeve layers with different diameters and different heights being sleeved and stacked inside and outside to form a trumpet-shaped structure in which one end is aligned and the other end gradually becomes a trumpet-shaped structure with an increasingly larger inner diameter. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the part close to the detection probe (23) in the middle of the two guide sleeves (22) is greater than the two side edges.

[0011] Furthermore, the single guide sleeve (22) is configured to be formed by splicing two semi-cylindrical structures, each semi-cylindrical structure is a structure in which a semi-cylindrical (223) with a large diameter and a large height is sleeved with a semi-cylindrical (224) with a small diameter and a small height to form a structure in which one end is aligned. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the part close to the detection probe (23) in the middle of the two guide sleeves (22) is greater than the two side edges. Wherein, the semi-cylindrical structure is formed by a plurality of hollow semi-cylindrical sleeves of different diameters and heights being overlapped and overlapped inside and outside to form a trumpet-shaped structure in which one end is aligned and the other end gradually becomes a trumpet-shaped structure with an increasingly larger inner diameter. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the part close to the detection probe (23) in the middle of the two guide sleeves (22) is greater than the two side edges.

[0012] According to the above technical scheme, the present invention has the following beneficial effects:

[0013] 1. The magnetically conductive guide sleeve in the magnetic saturation device of the present invention is designed to be thicker at the portion close to the middle detection probe and thinner at both sides, so as to achieve the concentration of magnetization of the metal tube rod to be detected at the middle portion closer to the detection probe without changing the ampere-turns of the magnetic saturation coil, thereby reducing the end blind area that cannot be fully magnetized and achieving a wider range of detection.

[0014] 2. The present invention is configured such that the two sides of the guide sleeve are thin, so that the diameter of the two sides of the channel of the magnetic saturation device is larger than that of the middle part, thereby shortening the small diameter length of the magnetic saturation device at the detection probe part. The channel of the magnetic saturation device can be designed to fit the metal pipe rod more closely, and the metal pipe rod will not be unable to pass through the detection channel due to the curvature of the metal pipe rod.

[0015] 3. The magnetic guide sleeve of the present invention is designed as a multi-piece splicing structure, which can realize the arbitrary combination of magnetic saturation device channels with different calibers, and the arbitrary combination and splicing of channels with different calibers. It is flexibly applicable to the detection of metal pipes and rods with different structural sizes, and the selection of magnetic guide sleeves of magnetic saturation devices with different caliber changes, combined with different ampere-turns of magnetizing coils, to reduce the heat loss of the magnetic saturation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the use status of the best embodiment of the present invention;

[0017] Figure 2 It is a schematic cross-sectional view of the prior art structure;

[0018] Figure 3 It is a schematic diagram of the direction of magnetic lines of force in the prior art;

[0019] Figure 4 A schematic cross-sectional view of the structure of the best embodiment of the present invention;

[0020] Figure 5 A schematic diagram of the magnetic force lines of the best embodiment of the present invention;

[0021] Figure 6 A schematic cross-sectional view of a guide sleeve according to a preferred embodiment of the present invention;

[0022] Figure 7 A schematic diagram of the guide sleeve structure of the best embodiment of the present invention;

[0023] Figure 8 A schematic diagram of the guide sleeve structure in another preferred embodiment of the present invention;

[0024] Fig. 9 A schematic diagram of the guide sleeve structure in another preferred embodiment of the present invention;

[0025] Fig.10 A schematic diagram of the guide sleeve structure in another preferred embodiment of the present invention;

[0026] Fig.11 A schematic diagram of the guide sleeve structure in another preferred embodiment of the present invention;

[0027] Fig.12 This is a schematic diagram of the guide sleeve structure in another preferred embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but only represents selected embodiments of the present invention.

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0030] like Figure 1 and Figure 4 As shown, a device for reducing the end effect of eddy current detection of ferromagnetic tubes and rods is a magnetic saturation device 2 with a central channel 3 for eddy current detection of long metal tubes and rods 1, including a magnetizing coil 21, a guide sleeve 22 and a detection probe 23, characterized in that the guide sleeve 22 is set as a hollow cylindrical structure made of magnetic conductive material, the magnetizing coil 21 is arranged on the periphery of the guide sleeve 22, the two magnetizing coils 21 and the two guide sleeves 22 form a symmetrically arranged group, and an intermediate detection probe 23 is arranged in a group of magnetizing coils 21 and guide sleeves 22, wherein the outer diameter of the guide sleeve 22 is set as a cylindrical structure with the same diameter, and the hollow inner diameter of the guide sleeve 22 is set as a plurality of structures with different diameters, forming a group of magnetizing coils 21 and guide sleeves 22, the thickness of the part close to the intermediate detection probe 23 is greater than the two side edges. The trumpet-shaped magnetic conductive sleeve forms a magnetic focusing effect, such as Figure 3 The magnetic trend line diagram of the prior art, and Figure 5 In the modified magnetic force line trend diagram of the present invention, a group of symmetrically arranged guide sleeves 22 are formed to concentrate the magnetic force lines in the middle part near the detection probe 23, reducing the magnetization length of the magnetic saturation device on the detected pipe rod and reducing the length of the end blind area during the detection process.

[0031] Among them, Figure 6As shown in the figure, the ratio of the length of the hollow inner diameter large diameter D1 part to the length of the small diameter D2 part of the guide sleeve 22 is between 1:2 and 2:1. When the guide sleeve 22 is made of pure iron with good magnetic conductivity, the ratio of the length of the hollow inner diameter large diameter D1 part to the length of the small diameter D2 part is set to 1:1.

[0032] Further, such as Figure 7 and Figure 8 As shown, a single guide sleeve 22 is configured as a cylinder 221 with a large diameter and a large height and a cylinder 222 with a small diameter and a small height, which is sleeved to form a structure in which one end is aligned. When a group of guide sleeves 22 are symmetrically arranged, the thickness of the part close to the detection probe 23 between the two guide sleeves 22 is greater than the two side edges. Among them, a single guide sleeve 22 is formed by a plurality of hollow sleeve layers with different diameters and different heights being sleeved and stacked inside and outside to form a trumpet-shaped structure with one end aligned and the other end gradually becoming a trumpet-shaped structure with an increasingly larger inner diameter. When a group of guide sleeves 22 are symmetrically arranged, the thickness of the part close to the detection probe 23 between the two guide sleeves 22 is greater than the two side edges.

[0033] Further, such as Figures 9 to 12 As shown in, the single guide sleeve 22 is configured to be formed by splicing two semi-cylindrical structures, each semi-cylindrical structure is a semi-cylinder 223 with a large diameter and a large height, which is connected with a semi-cylinder 224 with a small diameter and a small height to form a structure with one end aligned. When a group of guide sleeves 22 are symmetrically arranged, the thickness of the part close to the detection probe 23 in the middle of the two guide sleeves 22 is greater than the two side edges. Among them, the semi-cylindrical structure is formed by a plurality of hollow semi-cylindrical sleeves of different diameters and heights being connected and superimposed inside and outside to form a trumpet-shaped structure with one end aligned and the other end gradually becoming a trumpet-shaped structure with an increasingly larger inner diameter. When a group of guide sleeves 22 are symmetrically arranged, the thickness of the part close to the detection probe 23 in the middle of the two guide sleeves 22 is greater than the two side edges.

[0034] The above is one embodiment of the present invention. In addition, it should be noted that any equivalent or simple changes made based on the structure, features and principles described in this patent concept are included in the protection scope of this patent.

Claims

1. A device for reducing the end effect of ferromagnetic tube and rod eddy current detection, a magnetic saturation device (2) with a central channel (3) for eddy current detection of a long strip metal tube and rod (1), comprising a magnetizing coil (21), a guide sleeve (22) and a detection probe (23), characterized in that The guide sleeve (22) is configured as a hollow cylindrical structure made of a magnetic conductive material, the magnetizing coil (21) is configured on the periphery of the guide sleeve (22), the two magnetizing coils (21) and the two guide sleeves (22) form a symmetrically arranged group, and an intermediate detection probe (23) is configured on a group of magnetizing coils (21) and guide sleeves (22), wherein the outer diameter of the guide sleeve (22) is configured as a cylindrical structure with the same diameter, and the hollow inner diameter of the guide sleeve (22) is configured as a plurality of structures with different diameters, so that a group of magnetizing coils (21) and guide sleeves (22) are formed such that the thickness of the portion close to the intermediate detection probe (23) is greater than the thickness of the two side edges.

2. A device for reducing the end effect of ferromagnetic tube and rod eddy current detection according to claim 1, characterized in that The ratio of the length of the hollow inner diameter large diameter D1 part to the length of the small diameter D2 part of the guide sleeve (22) is between 1:2 and 2:

1.

3. The device for reducing the end effect of ferromagnetic tube and rod eddy current detection according to claim 2, characterized in that When the guide sleeve (22) is made of pure iron with good magnetic conductivity, the ratio of the length of the hollow inner diameter large diameter D1 part to the length of the small diameter D2 part is set to 1:

1.

4. The device for reducing the end effect of ferromagnetic tube and rod eddy current detection according to claim 1, characterized in that A single guide sleeve (22) is configured as a cylinder (221) with a large diameter and a large height being sleeved with a cylinder (222) with a small diameter and a small height to form a structure in which one end is aligned. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the portion of the detection probe (23) between the two guide sleeves (22) is greater than that of the two side edges.

5. The device for reducing the end effect of ferromagnetic tube and rod eddy current detection according to claim 4, characterized in that The single guide sleeve (22) is formed by a plurality of hollow sleeve layers of different diameters and heights being overlapped and connected inside and outside to form a trumpet-shaped structure with one end aligned and the other end gradually changing into a trumpet-shaped structure with an increasingly larger inner diameter. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the portion of the detection probe (23) between the two guide sleeves (22) is greater than that of the two side edges.

6. The device for reducing the end effect of ferromagnetic tube and rod eddy current detection according to claim 1, characterized in that A single guide sleeve (22) is configured to be formed by splicing two semi-cylindrical structures, each semi-cylindrical structure being a structure in which a semi-cylinder (223) with a large diameter and a large height is sleeved with a semi-cylinder (224) with a small diameter and a small height to form one end-aligned structure, and when a group of guide sleeves (22) are symmetrically arranged, a portion of the detection probe (23) close to the middle of the two guide sleeves (22) is formed to have a thickness greater than that of the two side edges.

7. The device for reducing the end effect of ferromagnetic tube and rod eddy current detection according to claim 6, characterized in that The semi-cylindrical structure is formed by a plurality of hollow semi-cylindrical sleeves of different diameters and heights being overlapped and connected inside and outside to form a trumpet-shaped structure with one end aligned and the other end gradually changing into a trumpet-shaped structure with an increasingly larger inner diameter. When a group of guide sleeves (22) are symmetrically arranged, the thickness of the portion of the detection probe (23) between the two guide sleeves (22) is greater than that of the two side edges.

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