SU1627969A1 - Method for adjusting defectoscope to test ferromagnetic tube - Google Patents

Abstract

The invention relates to non-explosive control and can be used for flaw detection of ferromagnetic conductive pipes, mainly drilling casing and tubing in exploration and production wells. The purpose of the invention is to increase the reliability of the control, which is achieved by the simultaneous detuning from the influence of the variation of the electrical conductivity and magnetic permeability of the pipe material. The eddy current transducer 2 is in electromagnetic interaction with the tube section. The equality of the signal increments on the first pair of measuring coils 4 and 5 by selecting the number of turns when the tube 17 is heated or cooled. In the same way, the second pair of measuring coils is balanced when the tube is magnetized. The difference signals of the coil pairs of the phase shifter 7 are reformed until the influence of interfering parameters is eliminated. 1 Il.

Description

The invention relates to non-destructive testing, can be used in equipment for comprehensive monitoring of the technical condition of drill, casing and tubing in exploration and production wells, as well as in electromagnetic defectoscopy of various industrial products.

The purpose of the invention is to increase the reliability of control, is achieved by simultaneously detuning from the influence of variations in the specific electrical conductivity and magnetic permeability of the material are rough.

The drawing shows a block diagram of a device that implements a method for tuning the flaw detector.

The device contains a sinusoidal oscillation generator 1, an eddy current transducer 2, consisting of an exciting coil 3 and a pair of measuring coils 4, 5 (the remaining pairs of coils are not shown), a digital voltmeter 6, a phase shifter 7, a reference voltage transformer 8, a phase-sensitive detector 9, a digital recorder 10 ( analogue) recordings. The exciting coil 3 of the Converter 2 and the primary winding of the transformer 8 of the reference voltage are connected in series with each other, and the secondary ends are connected to the generator 1 of sinusoidal oscillations.

The measuring coils 4 and 5 through the switches 11. 12, 13 are connected to the input of the phase shifter 7, a digital voltmeter 6 (alternately closed contacts 14, 15 and 14, 16) and the first input of the phase-sensitive detector 9 (closed contacts 17. 18 of the switch 13). In this case, the secondary winding of the transformer 8 is connected to the second input of the phase-sensitive detector ego 9. And the output of the phase shifter 7 through the PZ switch (closed contacts 17, 19) with the first input of the phase-sensitive detector 9, and the output of the last one is from the input of the digital (analog) recording recorder 10.

The method is implemented as follows.

The eddy-current transducer 2 is placed inside the length of the pipe from the casing on centering springs (not shown). The excitation coil 3 and the primary winding of the transformer 8 are fed from the generator 1 of sinusoidal oscillations. As a result of the interaction of the alternating magnetic field of the exciting coil 3 and the pipe wall 20. In the latter, eddy currents are induced. kotopny in turn induce EMF in measuring coils 4 and 5.

The equality of the signal increment on the first pair of measuring coils 4 and 5 is established when the electrical conductivity is varied by selecting the number of turns when heating a pipe segment 17 in a heating cabinet (not shown) in the temperature range 25.50, 100, 150, 200, and 250 ° C, while the contacts the switch 11 is set to position 15, 14 and 14, 16 in turn.

Similarly, the equality of the increment of the signals on the second pair of measuring coils (not shown in the drawing) from the influence of magnetic permeability by magnetizing the length of the pipe 20 in the solenoid (in the drawing) is established.

Then, the signals of each pair of measuring coils are counter-summed. For instance. for coils 4, 5, the switch 12 is set and the position is open. Using a phase shifter 7, the difference signal of these coils is rotated in phase until the effect of magnetic permeability is eliminated when the length of pipe 20 in the solenoid is magnetized. In the same way, the difference signal of the second pair of measuring coils is established in the third phase until the effect of electrical conductivity is eliminated when the pipe section 20 is heated. The phases of the difference signals are fixed in this position.

Claims (1)

Claim A method for tuning a flaw detector for monitoring ferromagnetic pipes, comprising a transducer consisting of an exciting coil and a pair of measuring coils according to the number of controlled parameters, namely, that the transducer is brought into electromagnetic interaction with a control sample in the form of a pipe segment from a casing string, and its specific electrical conductivity is changed (J by a given value by heating or cooling a pipe segment and evaluate the effect of this parameter, characterized in that, in order to increase detuning accuracy, additionally evaluate the effect of magnetic permeability μ by magnetizing the pipe segment, while first setting the equality of the increment of signals from one pair of measuring coils from a change in σ, on the second pair from the change in μ by selecting the number of whigs, the signals of each pair of measuring coils are summed up, rotate in phase the difference signal of the first pair until the effect is magnetically eliminated!! acceptability during the magnetization of the pipe segment, and the difference signal of the second pair to the device The effects of electrical conductivity during heating or cooling of a pipe segment are fixed and the phases of difference signals are fixed in this position.