CN114660167A

CN114660167A - External-through type elastic array coil eddy current detection probe

Info

Publication number: CN114660167A
Application number: CN202011526466.7A
Authority: CN
Inventors: 肖镇官; 崔洪岩; 赵德华; 石志彬; 黄灿; 王万国; 曾玉华
Original assignee: Research Institute of Nuclear Power Operation; China Nuclear Power Operation Technology Corp Ltd
Current assignee: Research Institute of Nuclear Power Operation; China Nuclear Power Operation Technology Corp Ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-06-24

Abstract

The invention discloses an external penetration type elastic array coil eddy current detection probe, which comprises an elastic array coil eddy current probe and an elastic axial winding type coil eddy current probe which are connected together. The elastic array coil eddy current probe is of a columnar through hole structure. The elastic axis-wound coil eddy current probe is of a cylindrical through hole structure. The beneficial effects are that: the qualitative and three-dimensional shape reappearance of the defects discovered by the eddy current probe which externally passes through the elastic shaft-wound coil is carried out, so that a basis is better provided for the reason analysis of the defects.

Description

External-through type elastic array coil eddy current detection probe

Technical Field

The invention belongs to the field of nondestructive testing of small-caliber pipes or bars, and particularly relates to an external penetration type elastic array coil eddy current testing probe.

Background

At present, a small-caliber pipe or bar generally uses an externally-penetrating type axial-winding probe to implement eddy current detection due to the structural characteristics of the pipe or bar, the method can only detect the size and the position of a defect, the property and the three-dimensional appearance of the defect cannot be determined, meanwhile, due to the influence of the end effect of the pipe (bar), an end blind area can occur, the risk of missed detection near the end exists, and the detection probe has certain limitation. Taking a nuclear power plant fuel rod as an example, the nuclear power plant fuel rod is formed by wrapping nuclear fuel in a zirconium alloy cladding with the wall thickness of about 0.5 mm, and welding and sealing are respectively carried out by adding a plug at each end, so that the nuclear power plant fuel rod is a first safety barrier for preventing nuclear leakage, and the inspection of an outer cladding is particularly important. Because the fuel rod can only be detected from the outside, the eddy current detection is mainly carried out at home and abroad by adopting an externally-penetrated axial-wound coil probe at present, the position and the size of the defect can be found by the technology, but the found defect cannot be qualitatively (such as crack, abrasion and the like). With the gradual maturity of the eddy current array technology, an external-through elastic array coil eddy current detection probe is developed on the basis of the array technology, qualitative analysis can be carried out on defects generated by a fuel rod, corresponding measures are made to avoid secondary damage of a fuel assembly due to the same reason, and safety and reliability of the fuel assembly during operation are guaranteed.

Disclosure of Invention

The invention aims to provide an external penetration type elastic array coil eddy current detection probe, which is used for qualitatively and three-dimensionally reproducing defects discovered by external penetration of an elastic axial winding type coil eddy current probe, so that a basis is better provided for analyzing the causes of the defects.

The technical scheme of the invention is as follows: an external penetration type elastic array coil eddy current detection probe comprises an elastic array coil eddy current probe and an elastic axial winding type coil eddy current probe which are connected together.

The elastic array coil eddy current probe is of a columnar through hole structure.

The elastic axis-wound coil eddy current probe is of a cylindrical through hole structure.

The elastic array coil eddy current probe comprises a shell, an array framework and an array sliding block are arranged in the shell and fixedly connected, a through hole is formed in the middle of the array sliding block, a coil is arranged in the middle of the array sliding block, a ferrite magnetic core is fixed in the middle of the coil, and an annular spring is sleeved on the periphery of the array sliding block.

The shell is of a hollow cylindrical structure.

The middle parts of the array frameworks are all provided with through holes.

The array framework is fixedly connected with the array sliding blocks.

The invention has the beneficial effects that: the ferrite magnetic core is arranged in the center of the small-diameter flat coil and then is arranged in the array sliding block together to form a detection unit, and the detection unit has high detection sensitivity on the surface and the inner surface of a detected pipe (or bar) and can effectively reduce the influence of an end effect. A plurality of detecting element install in the spout of array slider, the spout of array slider adopts the arrangement structure of two-layer dislocation, and every layer is arranged 6 detecting element, and two-layer totally 12 can densely cover in the circumference position of examined tubular product (or rod). Annular spring installs in the recess of array skeleton, and annular spring produces pressure and makes the array slider pop out and laminate with examined tubular product (or rod) surface, makes the filling rate of array coil reach 100%, guarantees the stability that the array coil detected, if there is deformation or swelling deformation such as examined tubular product (or rod), the array slider can be along with deformation or swelling shrink freely and laminate with the surface all the time, effectively prevents the risk that the probe blocked.

Drawings

FIG. 1 is a schematic diagram of an external-through elastic array coil eddy current inspection probe according to the present invention;

FIG. 2 is a cross-sectional view of FIG. 1;

FIG. 3 is a side sectional view of FIG. 1;

FIG. 4 is a partial cross-sectional view of FIG. 1;

fig. 5 is a partial cross-sectional view of fig. 1.

In the figure: the device comprises a tested pipe 1, an elastic array coil eddy current probe 2, an elastic axial winding type coil eddy current probe 3, a shell 21, an array framework 22, a ring spring 23, an array sliding block 24, a coil 25 and a ferrite magnetic core 26.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

The externally-penetrated elastic array coil eddy current probe has the advantages of high detection speed and high sensitivity, can be used for determining the defect type, and can also form the defect three-dimensional shape according to each circumferentially-equally-divided array coil. The probe adopts an innovative structural design, improves the filling coefficient of the probe, and avoids the blocking risk caused by structural changes such as deformation or swelling and the like in the inspection process. The structure principle of the external-through elastic array coil eddy current probe is that a plurality of flat coils simultaneously detect the outer surface of a pipe (or a bar), the flat coils are distributed in an array at the circumferential position of the pipe (or the bar) and are tangent to the outer surface of the pipe (or the bar), and the filling rate at the tangent position can reach 100%. The flat coil adopts a flat structure with a very small diameter, the influence of the internal structure of a pipe (or a bar) on an eddy current signal can be eliminated, and the ferrite magnetic core is added in the center of the flat coil to focus the eddy current signal, so that the influence of the end effect of the coil is reduced. The invention can be simultaneously implemented with an externally-penetrated elastic axis-wound coil eddy current probe, and can carry out full-coverage detection on the pipe (or bar), thereby overcoming the defects of the traditional externally-penetrated axis-wound coil probe.

As shown in fig. 1, an external penetration type elastic array coil eddy current testing probe comprises an elastic array coil eddy current probe 2 and an elastic axis winding type coil eddy current probe 3, wherein the elastic array coil eddy current probe 2 and the elastic axis winding type coil eddy current probe 3 are connected together and are of a cylindrical through hole structure, and a pipe 1 to be tested penetrates through a through hole in the middle of the elastic array coil eddy current probe 2 and the elastic axis winding type coil eddy current probe 3.

As shown in fig. 2-4, the elastic array coil eddy current probe 2 includes a hollow cylindrical housing 21, an array skeleton 22 and array sliders 24 are installed in the housing 21, through holes are formed in the middle of the array skeleton 22, the array skeleton 22 is fixedly connected with the array sliders 24, the number of the array sliders 24 in this embodiment is 12, a coil 25 is provided in the middle of the array slider 24, a ferrite core 26 is fixed in the middle of the coil 25, and a ring-shaped spring 23 is sleeved on the periphery of the array slider 24.

The invention has the following characteristics:

the detection sensitivity of the pipe (or the bar) is improved by adopting the small-diameter flat coil and the ferrite magnetic core, the influence of an eddy current edge signal at the end part is reduced, and the full coverage of an eddy current detection area of the pipe (or the bar) is realized by combining an external-penetration type elastic coil eddy current probe.

The arrangement mode of small-diameter coils and multilayer dislocation is adopted, the number of layers is different according to the outer diameter of a pipe (or a bar), the flat coil array needs to be densely distributed at the circumferential position of a detected object, the detection sensitivity is improved, and the diameter of the coil is smaller than 2 mm.

The elastic structure is adopted to ensure that the filling rate of the array coil reaches 100 percent, and the blocking risk caused by the structural deformation of the pipe (or bar) can be effectively avoided.

The external-through type elastic array coil eddy current probe is fixed on a specific inspection device and is connected to an eddy current instrument through an extension cable, one end of a pipe (or bar) to be inspected penetrates through the axial position of a central hole of the external-through type elastic array coil eddy current probe at a constant speed, at the moment, the array framework drives the flat coil to expand along the radial direction and is tightly attached to the outer surface of the pipe (or bar) to be inspected under the action of the annular spring, and therefore the defect of the pipe (or bar) to be inspected is inspected.

Claims

1. The utility model provides an outer formula elasticity array coil eddy current inspection probe that passes through which characterized in that: comprises an elastic array coil eddy current probe and an elastic axial winding coil eddy current probe which are connected together.

2. An outside-feed elastic array coil eddy current inspection probe according to claim 1, wherein: the elastic array coil eddy current probe is of a columnar through hole structure.

3. An outside-feed elastic array coil eddy current inspection probe according to claim 1, wherein: the elastic axis-wound coil eddy current probe is of a cylindrical through hole structure.

4. An outside-feed elastic array coil eddy current inspection probe according to claim 1, wherein: the elastic array coil eddy current probe comprises a shell, an array framework and an array sliding block are arranged in the shell and fixedly connected, a through hole is formed in the middle of the array sliding block, a coil is arranged in the middle of the array sliding block, a ferrite magnetic core is fixed in the middle of the coil, and an annular spring is sleeved on the periphery of the array sliding block.

5. An outside-feed elastic array coil eddy current inspection probe according to claim 4, wherein: the shell is of a hollow cylindrical structure.

6. An outside-feed elastic array coil eddy current inspection probe according to claim 4, wherein: the middle parts of the array frameworks are all provided with through holes.

7. An outside-feed elastic array coil eddy current inspection probe according to claim 4, wherein: the array framework is fixedly connected with the array sliding blocks.