SU1203421A2 - Device for testing continuity of dielectric coating in metal pipes - Google Patents

Description

The invention relates to the field of materials research by measuring active resistance, in particular for detecting defects in conductive coatings of pipes.

The aim of the invention is to improve the quality of control of the integrity of the coating.

FIG. 1 shows the device, a general view; in fig. 2 - one element of the sliding contact.

The device contains a cylindrical cavity I, inside of which there is a voltage converter 2. A shell is put on the casing, made of steel wires 3, the ends of which have a dielectric coating, increasing linearly from the end of the wire to the middle. The ends of the wires are trimmed and fused together, forming rings 5 and 6 on both sides of the sheath, while ring 5 is fixed to the housing fixedly, and ring 6 clamped by nut 7 is mounted slidably and rotated with respect to the housing. At both ends of the housing, coupling mechanisms 8 are installed, which serve to couple with the propulsion device 9 and centralizer 10 when the device moves in pipe 11. Electric power is supplied via cable 12, which is also a data transmission line.

The device works as follows.

Before switching on, it is regulated by moving the ring 6 until it stops and rotating it, until it reaches the required diameter. In this case, each of the wires of the sheath is bent and twisted into a loop perpendicular to the axis of the device, and the size of the loop, and with it the diameter of the ring contact, is determined by the angle of movement of the movable ring relative to the housing. The contact obtained takes the form of a funnel with a metal rim, and since each wire is made with a dielectric coating, it lies adjacent

to a friend, the coatings form an airtight surface. After adjusting the device in this way, it is placed in the pipe under test and the supply voltage is applied to the device. At the same time, compressed air is supplied to the pipe. The supply of voltage drives the propeller and the device begins to move. This movement is further facilitated by an inflating sliding contact, which, moving, penetrates into all irregularities of the coating. The voltage from the converter 2 is supplied to the sliding contact, and when the contact is pulled over the microcrack, a corona discharge occurs, which leads to an increase in current. Registration in the coordinate system — the current allows determining the size and position of the defect.

The use of this device is possible without the use of a body movement in it - the sensor is moved only by the action of compressed air. This allows the device to be used in pipes with bends of small diameters, since the length of the sensor in this case is shorter (without the propulsor).

5 Making the ends of the wires with a dielectric coating improves the quality of measurements due to the closer fit of the working part of the contact to the test surface. The air support behind the device, created during operation, additionally bends the working part of the contact, forcing it to penetrate into all irregularities of the coating under investigation. The increase in coating thickness is related to the fact that the object of study is pipes, pipes of different diameters, and since the circumference varies linearly relative to the radius, then the thickness of the dielectric coating must change according to the same law All the pipe section was blocked.

five

FIG. g

Claims (1)

(541 DEVICE FOR CONTROL OF THE CONDITION OF DIELECTRIC COATINGS IN METAL PIPES according to ed. according to the linear law, and the length of the coating at each end of the wire is equal to the length of the area free from coverage.