SU1242809A1 - Contactless eddy-current instrument transducer for checking properties of metal products - Google Patents

Abstract

The invention relates to the means of instrumentation technology and can be used for non-destructive testing of the properties of hardware. Accuracy control is determined by recording the position of the product. The converter contains a cylindrical dielectric core, on the central part of which. an excitation coil is placed, at different ends — the bottom — cylindrical measurement coils connected in opposite, and from the working end two mutually perpendicular measuring coils in the form of eights. Cylindrical measuring coils allow (LT to be rebuilt from zazrr, eight-shaped coils from the distortions of the transducer. 2 Ill. And ivd

Description

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The invention relates to instrumentation and control technology and can be used to control the physicomechanical properties of hardware by the eddy current method.

The purpose of the invention is to improve the control accuracy by registering the position of the product.

 FIG. 1 shows the eddy current transducer design; figure 2 - the dependence of the signal and the transducer from the gap d and the angle of the transducer to the product.

The transducer 1 is located at a distance d from the surface 2 of the product, and contains a cylindrical dielectric nonmagnetic core 3 and excitation coil 4 placed on it and three pairs of measuring coils: two end cylindrical measurement coils 5, a twin measuring coil 6 in the shape of eight and installed therewith, at the right angle, the second dual measuring coil 7 in the shape of a figure eight. The measurement coils 5 are placed at different ends of the core 3 and -in-on

During converter operation: the excitation carcass is connected to a generator (not shown), and the measuring coil through an amplifier and a synchronous detector is connected to a signal processing unit (not shown) through an amplifier.

The Converter operates as follows.

The generator generates a sinusoidal high frequency voltage, which causes a current to appear in the excitation coil 4. With this, the current of the coil 4 causes an electromagnetic field around it that intersects the coils of coils 5-7, If there are no conductive objects in the zone of the excited field, they are symmetrical with respect to all coils (for example, a conductive screen), the EMF of all coils combined in pairs, are mutually compensated by the counter-switching and the signal on all three outputs of the converter is absent.

If, on the side of one short circuit, the ends of the sensor of a conducting or ferromagnetic object appear, the surface of which is parallel to the planes of coils 6 and 7, the field is 809, 2

still symmetrically with respect to these coils, but the appearance of eddy currents in the conductive surface redistributes the flows through the face

coil 5 measurement. This causes the appearance of the: nostatic voltage, the value of which is determined by the gap between the transducer and the product. If the gap d is constant,

and the angle of inclination of the transducer to the product changes, the signal at the output of coils 5 is absent, and the signal at the output of coils 6 and 7 is determined by the value of the angle of inclination, and EMF determined by the angle of inclination in perpendicular planes x.

Typical dependences of the output voltages of the converter 1 on its polyolene relative to the surface 2 being monitored are shown in Fig.2. Curve 8 reflects the dependence of the outputs on the signal of the converter on the gap d., And curves 9 and 10 show

KHKHFvi in the manner and to what extent the sensitivity of the transducer varies according to the angle f X and RU with different gaps d and d7 between the transducer and the product. From the curves of FIG. 2, it is seen that the signal of the transducer in the range d /) and d almost linearly depends on the gap, and also linearly depends on the angle of inclination of the transducer in the range from 1 to 10 °.

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Claims (1)

Invention Formula 5s1 contactless eddy current transducer. Ss: to control the properties of the metal yy containing a cylindrical dielectric core, cylindrical bozou coils / probes and measurements placed on it, and an eight-shaped measuring coil located on the end of the core, characterized by in order to improve the control accuracy by registering the position of the product, it is equipped with a second cylindrical measurement coil, connected in opposition to the first coil, a second measuring coil in the shape of figure eight, set perpendicular to the first coil, and cylindrical measurement coils are placed at different ends of the core. FIG. one At: . Editor A.Shishkin Compiled by V.Filinov Tehred L. Oleiyik Proofreader E. Roshko Order 3696/41 Edition 778 Subscription VNIIPI USSR State Committee for inventions and discoveries. 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing: enterprise, Uzhgorod, Projecto st., 4 FIG. 2