Flow-control valve with valve member position sensor

摘要

A valve member position sensor for continuously monitoring the position of the valve member of a flow-control valve in a dry-cleaning apparatus using CO2 as the cleaning fluid. The valve member position sensor includes a potentiometer with its shaft connected to the drive shaft of the valve such the resistance of the potentiometer changes with the valve member position. The resistance value of the potentiometer is detected by passing a constant current through the potentiometer to produce a voltage drop across the potentiometer. The voltage drop is measured by a controller to determine the valve position.