Eddy current tube testing by aligned coils - coupled with saw-tooth generator supplying data to coordinate writer

摘要

A tube to be non-destructively tested for defects and/or inclusions by eddy currents is passed through the aligned annular test coils coupled with an AC source with adjustable frequency and amplitude. The coils are linked with resistances to form a test bridge and emit signals proportional to amplitude and phase retention of the coils. To these signals is added a voltage proportional to the length of test-piece which has passed through the coils. The combined signal is applied to the input terminal of an x/y coordinate writer to produce representation of the inductive behaviour of both coils. The amplifier used includes a Saw-tooth generator. USE - Provides reliable information on nature, position and structure of anomalies, e.g. in fast-breeder reactor tubes.