A.P. Pudovkin – Dr.Sci. (Eng.), the professor, the head of the department of «Radio Engineering», Tambov State Technical University. E-mail: firstname.lastname@example.org
J.N. Panasjuk – Ph.D. (Eng.), associate professor of «Radio Engineering», Tambov State Technical University. E-mail: email@example.com
S.P. Moskvitin – Ph.D. (Eng.), associate professor of «Radio Engineering», Tambov State Technical University. E-mail: firstname.lastname@example.org
Improvement of quality of multilayered metals is connected not only with improvement of manufacturing techniques and processing equipment for their production, but also with application of nondestructive methods of continuous quality control. The method of vortex currents belongs to such methods. Use of contactless sensors in the measuring devices based on use of a method of vortex currents, gives the chance to exercise the high-speed automated control.
For measurement of a continuousness of layers of bimetal depth of penetration of vortex currents we choose more than layer thickness, that is h > δ. The sinusoidal current of the second frequency operating in exciting (primary) windings measuring and reference coils, creates an electromagnetic field which raises vortex currents in an electroconductive top layer of a bimetallic strip. These vortex currents fade in process of penetration of deep into studied object.
The electromagnetic field of vortex currents influences secondary windings of measuring and reference coils, directing in them EDS which are proportional to change of a continuousness of connection of layers of bimetal and a standard. Tension of the reference coil also constantly, and tension of the izmeritelkny coil supervising a continuousness of connection of layers of a bimetallic strip, changes depending on change of a continuousness of connection of layers and thickness of a layer of bimetal.
The resultant signal is given on the demodulator at which exit the straightened tension proportional in size to change of a continuousness of connection of layers and thickness of bimetal from set standard will be created. This tension will be transformed and moves on an entrance of the microprocessor device where signals at the first and second frequencies are compared and on a difference of tension judge change of a continuousness of connection of layers of bimetal.
Thus, the deviation of thickness of the second layer and a continuousness of connection of layers of bimetal from a standard determine respectively at the first and second frequencies by tension change on the second winding of the measuring coil concerning tension to a secondary winding of the coil located over a standard.