SU1206689A1 - Magneto-acoustic converter - Google Patents

Description

The invention relates to non-destructive testing of materials and products from them by the electro-magnetic method and can be used primarily in mechanical engineering.

The purpose of the invention is to increase the sensitivity of the converter.

FIG. 1 shows an electrical circuit diagram of a converter; in fig. 2 is a schematic representation of the proposed converter in FIG. 3 is a view A of FIG. 2

The magnetoacoustic transducer contains a magnet 1, flat coils 2 and 3 of excitation and reception, respectively, the latter are located under the end of magnet 1, and each of them lies in a plane parallel to the plane of the end of the magnet. In addition, four transducer tips A-7 are mounted in the transducer, which are fixed at the end of the magnet 1 opposite alternating poles, while the receiving coil 3 is made in the form of two sections 8 and 9 connected in series, the displaced sides are 1x and the opposite sides of the coil 2 are excited arranged at pole pieces oppositely 4-7 magnet 1 and the coil 2 is arranged above both drive sections 8 and 9 of reel 3 doses.

The Converter operates as follows.

In the controlled surface of the article. (Not shown), eddy currents are induced by the coil 2, which, interacting with the constant magnetic field of the magnet

2

VNIIPIZakaz 8703/45

Circulation Subscription

Branch PSh1 Patent, Uzhgorod, Proektna St., 4

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create an electrodynamic force, in all areas directed in one direction. Under the action of this force, acoustic oscillations are excited in the controlled article (material). These vibrations propagate through the material of the product, are reflected from its opposite side (or defective place) and return back, causing eddy currents under the action of the magnetic field of magnet 1 on the surface of the controlled product (material). These eddy currents excite in-phase signals in sections 8 and 9 of coil 3, which are connected in series. The addition of these signals doubles the resulting signal, thereby increasing the sensitivity of the converter.

In addition, the execution of the receiving coil 3 in the form of two sections 8 and 9 connected in series, the adjacent sides of which are placed under opposite pole pieces 4, 5 and 6, 7, as well as the location of the excitation coil 2 above the different sections 8 and 9 of the receiving coil 3 and Under the opposite pole tips 5 and 6 of the magnet 1, during the generation of the excitation signal, the antiphase pickup of the signals in sections 8 and 9 of the receiving coil 3 is provided, since sections 8 and 9 of the receiving coil 3 are connected in series, these signals are mutually canceled. Thus, any signals induced by the excitation coil 2 in the reception coil 3, which cause significant interference to the receiving path of the converter, are eliminated.

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Claims (1)

MAGNETO-ACOUSTIC TRANSDUCER containing a magnet, flat excitation and reception coils, which are located under the end of the magnet and each of which lies in a plane parallel to the plane of the end of the magnet, characterized in that, in order to increase the sensitivity of the converter, it is equipped with four pole tips that are fixed at the end of the magnet with opposite alternating poles, and the receiving coil is made in the form of two series-connected sections, the adjacent sides of which and the opposite sides of the coils and the excitations are located under opposite pole tips of the magnet, while the excitation coil is located above both sections of the receiving coil.