CN104698075B

CN104698075B - Spiral pipe eddy current testing probe

Info

Publication number: CN104698075B
Application number: CN201310651300.1A
Authority: CN
Inventors: 肖镇官; 张伟; 王家建; 吴磊; 冯俊; 王元辉
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: 2013-12-05
Filing date: 2013-12-05
Publication date: 2020-06-19
Anticipated expiration: 2033-12-05
Also published as: CN104698075A

Abstract

The application belongs to the probe, concretely relates to spiral pipe eddy current testing probe. The spiral tube eddy current detection probe comprises a winding shaft, a large bead, a small bead and a fixing block, wherein the winding shaft is arranged at the foremost end of the probe and is an excitation and induction part of an eddy current signal, an excitation coil is arranged on the winding shaft, the outer diameter of the winding shaft is larger than 80% of the inner diameter of a detected tube, and the length of the winding shaft is smaller than or equal to twice of the inner diameter of the detected tube. The application has the following effects: the spiral tube eddy current detection probe is characterized by high detection sensitivity, good flexibility of the probe, few contact points between beads and the inner wall of the spiral tube and small friction force. The use of such a probe allows smooth passage through the entire spiral pipe.

Description

Spiral pipe eddy current testing probe

Technical Field

The application belongs to the probe, concretely relates to spiral pipe eddy current testing probe.

Background

Most of the existing heat transfer tubes of heat exchangers use a U-shaped tube structure, and spiral tubes (shown in figure 1) have become special heat transfer tubes of heat exchangers due to the characteristics of good heat exchange effect, compact structure and the like. However, eddy current testing of spiral pipes is difficult. At present, no eddy current probe for detecting the spiral tube exists at home and abroad.

The inspection of whole pipe just can be accomplished to interior through formula BOBBIN probe in the use of conventional U type heat exchange tube, and nylon tube is adopted to ordinary interior through formula BOBBIN probe outside, but when the motion in the coil pipe, the phenomenon of "locking" appears very easily in the nylon tube, leads to the probe to pass through the coil pipe smoothly.

In order to reduce the forward resistance of the probe, a special ball type structure is adopted, the flexibility of the probe is increased, the contact surface of the probe and the spiral tube is reduced to avoid the locking phenomenon of the probe, and the friction force is small when the probe passes through the inside of the spiral tube.

Disclosure of Invention

The utility model provides a can be convenient carry out the measuring probe that can strictly control strength size of surveying the spiral tube to prior art defect.

The technical scheme of the application is as follows: a spiral tube eddy current test probe comprises a spiral tube eddy current test probe consisting of a winding shaft, a large bead, a small bead and a fixed block, wherein the winding shaft is arranged at the foremost end of the probe and is an excitation and induction part of an eddy current signal, an excitation coil is arranged on the winding shaft, the outer diameter of the winding shaft is more than 80 percent of the inner diameter of a tested pipe, the length of the winding shaft is less than or equal to twice of the inner diameter of the tested pipe,

arranging large beads behind a winding shaft, and then arranging small beads, large beads and fixed blocks in turn, wherein a plurality of small beads need to be continuously arranged, and then large beads need to be arranged; the number of the small beads arranged at a single position is 8-12; only one large bead is arranged at a single position; the fixed blocks are arranged behind the large beads, and the distance between the adjacent fixed blocks or the fixed blocks and the winding shaft is half of the pitch of the tested spiral tube.

The spiral tube eddy current testing probe comprises a large ball body, a small ball body, a plurality of through holes, a plurality of spiral tubes and a plurality of spiral tubes, wherein the large ball body and the small ball body are both composed of a large ball body and a small ball body, the through holes penetrating through the two ball bodies are formed on an axis formed by the two ball centers, and the size of the hole formed at one end of the large ball body is equivalent to the diameter of the small ball body. Therefore, when a plurality of beads are connected in series end to end, the head of one bead and the tail of the other bead can be just sleeved together and can rotate flexibly. The large beads and the small beads are different only in that the large spheres of the large beads and the large spheres of the small beads are large in size, the outer diameter of the large beads is about 90% of the inner diameter of the test tube, and the outer diameter of the small beads is about 80% of the inner diameter of the test tube. And a steel wire rope and a signal transmission line are arranged in the through holes of the large beads and the small beads.

The application has the following effects: the spiral tube eddy current detection probe is characterized by high detection sensitivity, good flexibility of the probe, few contact points between beads and the inner wall of the spiral tube and small friction force. The use of such a probe allows smooth passage through the entire spiral pipe.

Drawings

FIG. 1 is a schematic view of the construction of a spiral pipe;

FIG. 2 is a schematic structural view of a helical tube eddy current inspection probe provided herein;

FIG. 3 is a schematic diagram of the structure of large beads and small beads.

In the figure: 1. big bead, 2 little beads, 3, fixed block, 4 the spool.

Detailed Description

As shown in figure 2, the spiral tube eddy current testing probe comprises a spiral tube eddy current testing probe body and a spiral tube eddy current testing probe body, wherein the spiral tube eddy current testing probe body comprises a winding shaft 4, a large bead 1, a small bead 2 and a fixing block 3. Where the bobbin 4 is arranged at the foremost end of the probe, the bobbin 4 being the excitation and induction part of the eddy current signal. The exciting coil is arranged on the winding shaft, the wire diameter, the layer number, the number of turns and the inductance value of the exciting coil are selected according to the wall thickness and the material of the tested spiral tube, and the small defect can be detected only when the outer diameter of the winding shaft 4 is generally larger than 80% of the inner diameter of the tested tube. The length of the winding shaft is less than or equal to two times of the inner diameter of the detected pipe.

Arranging the large beads 1 behind the winding shaft 4, and then arranging the small beads 2, the large beads 1 and the fixed blocks 3 in turn, wherein the small beads 2 need to be continuously arranged in a plurality of numbers and then arranging the large beads 1; the number of the small beads 2 arranged at a single position is related to the pitch of the tested spiral tube, generally is 8-12, and if the pitch of the spiral tube is large, the number of the small beads 2 can be slightly more; only one large bead 1 is arranged at a single position; the fixed block 3 is arranged behind the large bead 1, and the distance between the adjacent fixed block 3 or the fixed block 3 and the winding shaft 4 is half of the pitch of the tested spiral tube.

As shown in figure 3, the large bead 1 and the small bead 2 have basically the same structure, and both consist of a large sphere and a small sphere, a through hole penetrating through the two spheres is formed on an axis formed by two sphere centers, and the size of the opening at one end of the large sphere is equivalent to the diameter of the small sphere. Therefore, when a plurality of beads are connected in series end to end, the head of one bead and the tail of the other bead can be just sleeved together and can rotate flexibly. The large beads 1 and the small beads 2 are different only in that the large spheres of the large beads 1 and the large spheres of the small beads 2 are large in size, the outer diameter of the large beads 1 is about 90% of the inner diameter of the test tube, and the outer diameter of the small beads 2 is about 80% of the inner diameter of the test tube. And a steel wire rope and a signal transmission line are arranged in the through holes of the large beads 1 and the small beads 2.

Fixed block 3 is used for fixed wire rope and signal transmission line, and fixed block 3 can let the laminating between the pearl inseparable to the inside signal transmission line of protection does not receive the damage. The structures of the processing bobbin 4, the large bead 1, the small bead 2, the fixed block 3 and the like need to select materials (such as plastics and nylon) with smaller hardness so as to avoid scratching the inner wall of the detected spiral pipe.

The small beads 2 function to reduce friction forces, primarily on the large beads, as the probe advances by gas/liquid propulsion.

The working process of the probe is as follows: the spiral tube eddy current detection probe is arranged on a propelling device, and the device is used for controlling the eddy current probe to move forwards and backwards in the spiral tube. Meanwhile, an eddy current instrument is used for acquiring an induction signal of the eddy current probe, and a characteristic signal is extracted to carry out defect analysis on the spiral pipe, so that eddy current detection on the spiral pipe is realized.

Claims

1. A spiral pipe eddy current inspection probe is characterized in that: the eddy current detection probe comprises a spiral tube eddy current detection probe, a plurality of small beads (2) and a fixing block (3), wherein the winding shaft (4) is arranged at the foremost end of the probe, the winding shaft (4) is an excitation and induction part of an eddy current signal, an excitation coil is arranged on the winding shaft, the outer diameter of the winding shaft (4) is larger than 80% of the inner diameter of a detected pipe, the length of the winding shaft is smaller than or equal to twice the inner diameter of the detected pipe, the large beads (1) are arranged behind the winding shaft (4), then the small beads (2), the large beads (1) and the fixing block (3) are arranged in turn, and the small beads (2) need to be continuously arranged and then the large beads (1) are arranged; the number of the small beads (2) arranged at a single position is 8-12; only one large bead (1) is arranged at a single position; the fixing blocks (3) are arranged behind the large beads (1), and the distance between the adjacent fixing blocks (3) or the fixing blocks (3) and the winding shaft (4) is half of the pitch of the spiral tube to be measured;

the large bead (1) and the small bead (2) are both composed of a large sphere and a small sphere, a through hole penetrating through the two spheres is formed in an axis formed by two sphere centers, and the size of an opening at one end of the large sphere is equivalent to the diameter of the small spheres, so when a plurality of beads are connected in series end to end, the head of one bead and the tail of the other bead can be just sleeved together and can rotate flexibly, the large bead (1) and the small bead (2) are only distinguished in that the large sphere of the large bead (1) is larger than the large sphere of the small bead (2), the outer diameter of the large bead (1) is about 90% of the inner diameter of a pipe to be detected, the outer diameter of the small bead (2) is about 80% of the inner diameter of the pipe to be detected, and a steel wire rope and a signal transmission line are arranged in the through hole of the large bead (1) and the small bead (2);

the fixed block is used for fixed wire rope and signal transmission line, and the fixed block can let the laminating between the pearl inseparable to the signal transmission line of protection inside does not receive the damage.