Position measuring device using change in inductance of coil, float-type flowmeter, and position measuring method

摘要

A float-type flowmeter measures the rate of a fluid flowing upwardly through a tube based on the position of a float movably disposed in the tube and including a magnetic material. A coil is wound around the tube such that the intervals gradually decrease in an axial direction. The coil is excited by an alternating current supplied from an inductance change detector. The inductance change detector detects a change in the inductance of the coil which is caused when the float moves in the axial direction, and generates a voltage. A voltage-to-position (flow rate) converter determines a flow rate from the voltage corresponding to the position of the float.