MAGNETIC SUBSTANCE CONCENTRATION MEASURING DEVICE AND MAGNETIC SUBSTANCE CONCENTRATION MEASURING METHOD

摘要

A magnetic substance concentration measuring device comprising an exciting coil (11a) and an output coil (11b) for generating an exciting voltage when an AC current flows through the exciting coil (11a). The device further comprises measuring means (6) for measuring a variation of the difference between the phases of the voltages of the exciting coil (11a) and the output coil (11b). From the variation of the phase difference occurring when an object under test is made to approach the exciting coil (11a) or/and the output coil (11b), the concentration of the magnetic substance is measured with high accuracy, and further the small concentration of the magnetic substance in a fluid can be continuously measured.