Differential coil arrangement for metal object detection - has whole number of coil segments connected together symmetrical to central main plane

摘要

Screening is arranged at least between the excitation and detection coils. A whole number of the coil segments (51,52) is symmetrically arranged w.r.t the central main plane (33) in the axial direction of the arrangement (50). The coils egments are of identical construction and connected together. They are pref. mirror-symmetrically arranged. The radial screening between the outer excitation winding (3) and the internal detector winding (1) is pref. in the form of a wound screen (5). The windings are pref. of lacquered wire. USE/ADVANTAGE - Precision detection of differences in physical values. Relatively simple matching to various requirements with equalising of symmetrical characteristic.