SU905622A1 - Strap electromagnetic converter - Google Patents

Description

one

The invention relates to non-destructive thickness control of non-magnetic coatings on ferromagnetic products of complex shape and can be used in all engineering enterprises.

Known invoice electromagnetic transducer containing the inductor with a core ferromagnetic core ll.

The disadvantage of this transducer is the low sensitivity to the coating thickness of the test item.

The closest in technical essence to the present invention is an invoice electromagnetic transducer comprising an excitation winding and two measuring windings connected in series with each other and located on both sides of the excitation winding placed on a ferromagnetic core core with a ball tip 21,

The disadvantage of such a converter is the low accuracy of control of small-sized products of complex shape, due to the edge effect.

The purpose of the invention is to improve the accuracy of control of small-sized products of complex shape.

The goal is achieved by the fact that the core is made with a two-layer pole tip in the form of a hollow truncated cone installed coaxially with the core, the smaller base of which faces the controlled product, the inner layer of the cone is made of a ferromagnet of thickness -1 -. . ) and the outer layer

Noah Njr 6i / Wo / t

made of non-ferromagnetic chofan material with thickness

7, j.

where is the excitation frequency of the converter, Hz;

Claims (2)

- specific electrical conductivity of ferromagnet, SIM / m; magnetic constant, early 4L. Yu GN / m; U- - relative magnetic permeability; (specific electrical conductivity of the material, SIM / m. The drawing shows the preform image. The converter contains excitation winding 1, terminals 2 are connected to a current source, excitation (not shown), and two measuring windings 3 and 4 connected in series oppositely, the conclusions 5 of which are connected to the measuring unit (not shown in the drawing). The windings are placed on the core ferromagnetic core 6 with the ball tip 7, the Pole tip is made in the form of a truncated cone and has an inner tr the magnet layer 8 and the outer conductive layer 9. The converter is mounted on a ferromagnetic controlled product with a non-magnetic coating 11. The converter operates as follows: An alternating current flows from the source connected to the leads 2 when the winding 1 is driven by an alternating current inducing winding electromotive force in windings 3 and 4 closed through the surrounding space, the inner layer 8 of the pole tip, coating 11 and the control of my product 10. The difference of the emf acting on the outputs 5, defined ate is the coating thickness and is its measure. At the same time, the inner ferromagnetic layer of the 8 pole tip concentrates the magnetic flux of the transducer in the region around the core 6, reducing the influence of the edge effect. This vi 8 of layer 8 is equal to or more than twice the effective penetration depth of the electromagnetic field of the converter into the metal of layer 8, which ensures a sufficiently small magnetic resistance of this section of the magnetic circuit of the converter. Exterior wire $ pts. the pole tip layer 9 shields the outer surface of the cone of the layer 8 from the surface 10, additionally localizing the transducer's electromagnetic field in the region around the core 6. The converter allows reducing the edge effect. The use of the proposed developer makes it more accurate to control small-sized products of complex shape and thereby increases their reliability and durability, as well as expands the range of controlled products. Formula of b and e Inverted electromagnetic transducer containing an excitation winding and two measuring windings connected in series oppositely and located on both sides of the excitation winding, placed on a ferromagnetic core core with a ball tip, characterized by accuracy of control of small-sized products of complex shape, the core is made with a two-layer pole tip in the form of a hollow truncated box, installed coaxially with the core, less warping which faces towards the controlled article, the inner layer of the cone br 1polnen ferromagnet thickness iJrfd M-o / and naruzh1P 1st layer is made of nonferromagnetic conductive material thickness where f - frequency of excitation of the transducer; (j / i is the specific conductivity of a ferromagnet, SIM / m; magnetic constant is 4J .-. iO-7rri / M; relative magnetic permeability; (iri is the specific conductivity of the SIM / m material. Sources of information taken into account during the examination 1. A. L. Dorofeev. Measurement of coating thickness using eddy currents, M., Mashinostroenie, 1975, pp. 52. 2. Devices for non-destructive testing of materials and products. Handbook, ed. V.V. Klyuev9, t, 2, M., 1976, p. 74-75 (prototype).