DEVICE FOR DETECTING ELLIPTICAL DEFORMATION OF CIRCUMFERENTIAL CROSS SECTION OF HEAT-EXCHANGER HEAT-TRANSFER TUBE

摘要

A device for detecting elliptical deformation of the circumferential cross section of a heat-transfer tube comprises: a main transducer body which is inserted inside a heat-transfer tube, and is provided in such a way as to be able to move in the longitudinal direction of the heat-transfer tube and to be able to rotate in the circumferental direction of the inside surface of the heat-transfer tube; support legs which are provided on both ends of the main transducer body and support the linear movement and rotation of the main transducer body; coil support parts which are formed in mutually different positions of the main transducer body; and eddy-current coils which are fitted to the coil support parts, and incorporate a first coil unit and a second coil unit for measuring eddy-current resistance in order to detect oval deformation of the cross section of the heat-transfer tube. In the eddy-current coil, either the first or the second coil unit is used as a test coil while the other is used as a reference coil, or else the first and second coil units are both used as test coils.