METHOD FOR CONTINUOUS CONTROL OF THICKNESS AND CONTINUITY OF BIMETAL LAYER JOINTS Russian patent published in 2010 - IPC G01B7/06 G01N27/90 

FIELD: physics.

SUBSTANCE: bimetal is exposed to an alternating magnetic field of an inductor coil with a flat-topped core piece. A measuring inductor coil is placed with clearance on the side of the ferromagnetic layer of the bimetal and a standard inductor coil is placed on the side of the ferromagnetic layer of the standard. Secondary windings of the inductor coils are connected in series - anti-parallel. Primary windings of the inductor coils are powered by alternating current with frequency at which the effective depth of penetration of eddy-currents is less than the thickness of the measured bimetal layer. Two double-winding hand probe windings are used, which are placed with clearance on the opposite side of the bimetal and standard sample respectively. Secondary windings of the coils are connected in series - anti-parallel , and primary windings are powered by alternating current on at least two frequencies. The first frequency is selected such that penetration depth of eddy currents is less than thickness of the controlled bimetal layer and the second is such that the said depth is greater than the said thickness. Deviation of thickness of the second layer and continuity of the joint of bimetal layers from the standard are determined at the first and second frequencies respectively from change in voltage across the secondary winding of the measuring coil relative voltage of the secondary winding of the coil lying above the standard.

EFFECT: higher accuracy and broader functional capabilities.

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