SU58998A1 - Device for detecting defects in articles made of magnetic material - Google Patents

Description

Devices for detecting defects in articles made of magnetic materials are already known, based on magnetization of the product by a strong magnetic field, in order to be able to detect defects in scattering flows that occur at the surface of the product above the damaged place. A system of coils that move near the surface of the product under investigation usually serves as indicators for detecting dispersion flows. When the coils hit the flow zone, some e is induced in them. D. s., which, after its amplification, is fed to a measuring device that records detected defects.

A large number of different amplifying circuits are used in installations for detecting defects in metal products. However, the direct amplification of pulses requires the use of very complex amplifying circuits, inconvenient and unreliable under the conditions of production testing. Therefore, it has already been proposed that voenikayush; in the inductor coils of defectocopes, it has already been proposed to convert impulses into alternating

voltage of significant frequency with the help of various accessories (buzzer interrupters, rotating capacitors of variable capacity, etc.). The resulting AC voltage is then amplified by a simplified conventional AC amplifier.

A feature of the device proposed according to the invention is the use of a so-called phonic oscillator as such an intermediate converter, the core of which is made of a material with a large initial magnetic permeability, for example, by the type of permalloy alloy.

The devil schematically shows the proposed device.

The product under investigation, in this case drill pipe 1, is fitted at the ends with screwed on attachments locks 2, 2, and magnetized by means of a ring electromagnet 3 worn on it. places of the product, serve several groups of indicator coils

5, 6, which, according to instructions, can be made as one or d: Vuh and more pairs of windings each, including pairs in pairs, towards each other.

Such an inclusion is usually used to eliminate the effects of various random External causes, for example, network voltage fluctuations, etc., which could be erroneously recorded as valid damages.

In the case of the use of one or more pairs included differentially: the coils, all external changes of the input voltage or magnetic flux will be equally effective; to exist on both coils, as a result of which e are induced in them. d. will be mutually compensated and will not affect the device registering defects.

Induced in and; n; dikatornyh ka; voltage, through a low-frequency filter, the state, Ii of the drossel 8 and the capacitors 9, is fed to the amplifier circuit. As mentioned above, j arises, under the influence of damaged places in the indicator coils, pulses are converted into alternating voltage, frequencies of the order of 300 hertz and higher, using a converter I, made in the usual way I leg. generator.

The latter consists of a core 10, between the poles of which the toothed iron disk 11 rotates.

Pulses of indicator coils are applied to one of the core windings 12, which create some weak magnetization of the core 10. When the disk 11 rotates, its teeth, alternately approaching the core poles, periodically clamp the magnetic circuit of the core, creating an alternating magnetic flux, the magnitude of which depends on the magnetizing measured current in the winding 12. Under the action of intermittent magnetic flux, an alternating voltage appears in the secondary winding 13 of the core, which is applied to the grid of the input lamp 14 o Common AC amplifier. A recording measuring device 15 is turned on at the output of the amplifier. As is seen from the diagram, the excitation of the device 15 (in this case, of the ferrodynamic type) can be carried out from a generator feeding the magnetizing device under investigation.

The subject matter of the invention.

A device for detecting defects in products made of magnetic material, based on the magnetization of the product under investigation and on the detection of magnetic fluxes scattered using a system of indicator coils connected through an amplifier, oh, and so on. conversion of pulses induced in the indicator coils, a mechanical transducer of the phonic generator type was used; ra, the core of which, in order to be able to transform very low voltages, is made of a material with large It is equipped with two windings, one of which is intended to be included in the circuit of the indicator coils, and the other in the input circuit of the amplifier.

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