RU2258218C1 - Electromagnetic acoustical transducer - Google Patents

Abstract

FIELD: measuring engineering.

SUBSTANCE: transducer comprises housing, substrate, cover, connectors, concentrators, inductive coils, and magnetic system made of permanent magnets. The magnetic system is made of three permanent magnets mounted inside the housing in parallel to the plane of the substrate and tightly pressed to each other. The polarization of the side magnets is arbitrary, and the central magnet has vertical polarization. The surface of the central magnet that faces the substrate is provided with concentrators which are arranged with a spaced relation to each other. The concentrators are made of carbonyl iron and impregnated with a glue. The coils and concentrators are glued to the ceramic plate mounted in the same plane as the bottom base of the substrate and are filled together with it with an epoxy resin. The plate made of a ferromagnetic material is mounted on the surface of the magnets from the opposite side.

EFFECT: enhanced sensitivity of the transducer.

Description

The invention relates to the field of ultrasonic non-destructive testing of materials and products and can be used, in particular, for quality control of products of the metallurgical industry (sheet, strips, long products, pipes, etc.).

Known EMAT containing permanent magnets and inductors [1]. In the well-known EMAT, an increase in its sensitivity is achieved due to the fact that it is equipped with three flat inductors, three concentrators made of ferromagnetic material and ring permanent magnets with alternating poles. A disadvantage of the known EMAT are large leakage flows and, as a consequence, low sensitivity.

Known EMAT, containing a non-magnetic housing, a cover, a connector and inductors mounted on a protective substrate of a dielectric [2], superimposed on one another, made in separate sections, wound with one wire and connected to a high-frequency generator.

A disadvantage of the known Converter is the need to place it in an external magnetic field to ensure operation.

The purpose of the invention is a significant increase in the efficiency of the Converter by reducing leakage flows and the concentration of most of the magnetic flux in the area of the inductance coils

To do this, in the proposed electromagnetic acoustic transducer, comprising a housing, a substrate, a cover, connectors, hubs, inductors and a permanent magnet magnetic system, the magnetic system is made of at least three permanent magnets mounted in the housing parallel to the substrate plane adjacent to each other to a friend, and the side permanent magnets have horizontal polarization, and the central one is vertical, on the surface of the central permanent magnet facing the substrate, along its greatest On the other hand, concentrators made of carbonyl iron powder impregnated with glue are installed with a certain step, coils and concentrators are glued to a ceramic plate mounted in the same plane with the lower base of the substrate, and filled together with it, for example, epoxy resin, and on the opposite side a plate of ferromagnetic material is mounted on the surface of all permanent magnets.

The proposed design of the magnetic system allows to obtain maximum induction under the central magnet. In practice, studies have shown that the entire magnetic flux generated by magnets is concentrated in the area of the inductors, which ensures a high level of signals reflected from defects during ultrasonic testing. The execution of concentrators of carbonyl iron powder ensures the absence of eddy currents in them, distorting the signals. The installation of a plate of ferromagnetic material on the surface of the magnets reduces the loss of magnetic flux due to leakage and allows you to receive stronger signals.

Figure 1 shows a longitudinal section of the EMAT (section A-A), figure 2 is a top view of the EMAT (the top cover is not shown conditionally), figure 3 is a transverse section of the EMAT (section BB).

The electromagnetic-acoustic transducer contains a housing 1, a substrate 2, a cover 3, connectors 4, a central permanent magnet 5, side permanent magnets 6, hubs 7, inductors 8, a ceramic plate 9, a plate 10 made of ferromagnetic material, screws 11.

The proposed EMAT can significantly increase the sensitivity and increase the efficiency of ultrasonic testing.

Sources of information

1. RF patent No. 2219539, Bull. No. 35, December 20, 2003

2. RF patent No. 2206888, Bull. No.17, 06/20/2003

Claims (1)

An electromagnetic-acoustic transducer comprising a housing, a substrate, a cover, connectors, hubs, inductors and a permanent magnet magnetic system, characterized in that the magnetic system is made of at least three permanent magnets installed in the housing parallel to the substrate plane to a friend, and the side permanent magnets have horizontal polarization, and the central one is vertical, on the surface of the central permanent magnet facing the substrate, along its largest torons are installed with a certain step; concentrators made of carbonyl iron powder impregnated with glue; coils and concentrators are glued to a ceramic plate mounted in the same plane with the lower base of the substrate and filled together with it, for example, epoxy resin, and on the opposite side to the surface all permanent magnets mounted plate of ferromagnetic material.

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