| 摘要 |
PURPOSE:To simultaneously inspect existence of an oxygen absorbing agent and a metallic foreign substance in an anti-oxidation object by passing a body to be inspected through an alternating magnetic field, extracting a magnetic substance component signal contained in a detected signal, and removing the magnetic substance component signal so as to extract a conductor component signal. CONSTITUTION:A magnetic field is generated by an oscillator 1 and a transmitting coil P, and change of a magnetic flux due to a body to be inspected is detected with detecting coils Sa, Sb and a preamplifier 2. The detected signal C is sent to a wave detector 3, and a magnetic substance signal (d) of low frequency is taken out. The signal (d) is sent to a first judging part 10, compared with the set level, and judged if it is iron particulate. It is inspected if an oxygen absorbing agent is enclosed in a vessel or if oxygen absorbing function is given to it. Meanwhile, the signal (d) is sent to a modulator 5, and modulated by voltage (a). The phase is adjusted by a phase shifter 6, a regenerated magnetic substance component signal (e) is sent to a differential amplifier 7. The signal (e) is subtracted from the signal (c) by the amplifier 7 so as to obtain a conductor component signal (f), compared with the set level at a second judging part 11 through a wave detector 9, so as to inspect mixing of metal. |
