RU2325638C1 - Inductor coil block for electromagnetic acoustic transducer - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: inductor coil block for the electromagnetic acoustic transducer consists of at least, two inductor coils, located one under the other, in which case each inductor coil, located on the upper layer, is displaced relative the other indictor with covering, satisfying the condition: 0<D<100 mm with overall length of the operational zone of the electromagnetic acoustic transducer equal to (L×N)-(D×N), where N is the number of inductor coils, L is the length of the coil, D is the overlap in millimetres. Each inductor coil has its own contacts for autonomous connection to its generator and receiver. The block of inductor coils can have any length of the operational zone and the inductor coils in the block can be laid out in several layers in rectilinear, curvilinear direction, along the perimeter or in a circle depending on the intended function of the ultrasonic control, form and direction of motion of the control object.

EFFECT: autonomous operation of the coils in different modes of different generators and receivers.

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Description

The present invention relates to the field of non-destructive ultrasonic testing of rolled products and can be used to detect internal defects of sheets, strips, long products and pipes made of ferromagnetic material.

Known electromagnetic-acoustic Converter containing two inductors spaced from each other along the horizontal axis to reduce electromagnetic interference [1]. The disadvantage of this arrangement of coils is the insufficient density of ultrasonic testing and the appearance of uncontrolled zones as a result of the location of the coils relative to each other at a distance.

A known electromagnetic-acoustic transducer, in which, in order to increase the sensitivity, an inductor consisting of two sections connected in series with each other, is installed symmetrically relative to the longitudinal axis of the U-shaped magnetic circuit, and the sections of the turns forming the bridge of the coil are located on the branch of the magnetic circuit, which made in the form of a truncated prism, the smaller base of which is the end of the branch [2]. The disadvantage of this arrangement of coils is the insufficient density of ultrasonic testing due to the presence of a jumper between the coil sections.

Known electromagnetic-acoustic transducer, which contains at least two inductors located in layers by stacking one on another with a shift in the winding direction and made in the form of separate sections, wound with one wire and laid close to each other, and the turns of one section inductors are located inside the space between the turns of sections of another inductor, and the ends are bent [3].

The disadvantage of this arrangement of coils is the high complexity of manufacture and the inevitable occurrence of interference and heterogeneity of the received signals due to the presence of bent ends of individual sections of the coils.

Known inductance coil of an electromagnetic-acoustic transducer, made on a dielectric board, single-layer or multi-layer, containing one or several sections, of various shapes, and in a multi-layer coil, the turns of one layer are located in the gap between the turns of another layer without overlapping, on one or on opposite sides coils and are interconnected, the transition from one layer to another is made through 2-3 turns, a paired ellipsoidal inductor is made of two autonomous sections, located nnyh the board in one plane, or one above the other on different sides of one board with the possibility of joint operation [4]. A disadvantage of the known multilayer coil, the sections of which are interconnected, is the impossibility of using these sections in an autonomous mode by connecting them to different generators and receivers, due to which it would be possible to increase the sensitivity of the electromagnetic-acoustic transducer.

Known electromagnetic-acoustic transducer, in which, in order to increase sensitivity, each inductor is multilayer in height from separate conductors connected in series with the transition from the overlying layer to the underlying layer through n turns separated from each other by a dielectric layer [5]. The known combination of arrangement and connection of sections ("butterflies") of the coil has the same drawback as the previous one. All coil sections are connected to each other in series, which does not allow each coil section to work autonomously in different modes independently of each other from different generators and receivers.

The aim of the invention is the creation of such a block (assembly) of inductors for EMAT, with such an arrangement and connection in it, which would ensure their autonomous, independent from each other operation in different modes from different generators and different receivers.

This goal is achieved by the fact that in the block of inductors for an electromagnetic-acoustic transducer containing at least two inductors located one below the other, each inductor located in the upper layer is offset from another inductor with an overlap that satisfies the condition : 0 <D <100 mm with a total length of the working area of the electromagnetic-acoustic transducer equal to (L × N) - (D × N), where N is the number of inductors, L is the length of the coil, D is the overlap in millimeter x, wherein each inductor has its own autonomous terminals for connection to the generator and its own receiver.

In addition, the block of inductors can have an arbitrarily large total length of the working area. Inductors in a block can be arranged in several layers, in a straight, curved direction, around the perimeter or around a circle, depending on the purpose of the ultrasonic testing, the shape and direction of movement of the test object.

Figure 1, a shows an autonomous inductor (N = 1) inductance with the length of the working zone L;

figure 1, b shows a block (assembly), consisting (assembled) of N-coils EMAT (not shown) with overlapping D;

figure 2 shows the location of the coils relative to each other in adjacent layers. “C” is the distance between the layers.

To obtain a high control density in one EMAT unit (not shown), several active elements of N-coils of inductance are installed (Fig. 1, a) having a certain length of the working zone L. The total length of the working zone of the EMAT in this case is the sum of the working lengths zones of elements N. In order to ensure uniform sensitivity characteristics of the entire EMAT unit, the superposition of coils N on each other is carried out according to Fig.2, b. Inductors are overlapped by a certain value of D, which is selected based on the requirements for the characteristics of the EMAT, and can vary in one direction or another. Thus, the total length of the EMAT working area is obtained, equal to (L × N) - (D × N) with the unevenness of the adjusted sensitivity characteristics in each channel N of not more than 2 dB.

The proposed block of inductors for EMAT allows you to control 100% of the surface of the object, regardless of its shape and direction of movement.

Information sources

1. RF patent No. 31305.

2. A.S. USSR No. 1758546.

3. RF patent No. 2206888.

4. RF patent No. 2268517.

5. RF patent No. 2265208.

Claims (1)

A block of inductors for an electromagnetic-acoustic transducer, comprising at least two inductors located one below the other, characterized in that each inductor located in the upper layer is offset relative to the other inductor with an overlap satisfying the condition 0 <D <100 mm, with a total length of the working area of the electromagnetic-acoustic transducer equal to (L × N) - (D × N), where N is the number of inductors, L is the length of the coil, D is the overlap, mm, with each coil and the inductance has its own conclusions for autonomous connection to its generator and its receiver, the block of inductors can have an arbitrarily large total length of the working area, the inductors in the block can be arranged in several layers, in a straight line, curvilinear, perimeter or circumference direction from the appointment of ultrasonic testing, the form and direction of movement of the object of control.

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