COIL UNIT FOR ELECTROMAGNETIC ACOUSTIC TRANSDUCERS Russian patent published in 2013 - IPC H01F27/30 

FIELD: physics.

SUBSTANCE: coil unit for electromagnetic acoustic transducers has a group of inductance coils lying one below the other with overlapping and are independently connected to their own receiver, wherein the group of coils has an arbitrarily large total length of the working zone, and coils in a group lie in several layers in a linear direction, a curvilinear direction or on a circle depending on the purpose of ultrasonic inspection, the shape and direction of movement of the inspected object, wherein the unit is provided with a second group of inductance coils connected to their own generators, lying above the first group of coils with complete or partial overlapping of coils of the first group; coils of the second group are placed with bias from each other in the direction of the transverse axis, wherein coils of both groups have a different number of windings, different width of working zone and different geometric configuration on the plane, and the length of the working zone L of coils of the first group is selected from the condition L=(N×Z)-(N-1)×C, where Z is the length of the working zone a coil, N is the number of coils, C is the overlap value for each neighbouring coils.

EFFECT: providing electromagnetically independent operation of coils on different modes from different generators, different receivers and generation of a uniform acoustic field on the entire width of the unit in a wide range of thickness of the inspected articles.

5 cl, 8 dwg