Measurement arrangement for determining valve stroke employs stroke dependent capacitance with reference capacitor to compensate for temperature conditions

摘要

A stroke transducer (7) has two electrodes, a measurement electrode (3) and a reference electrode (4) forming first and second capacitors. A section of dielectric (6) embedded in the valve shaft passes the first capacitor so varying its capacitance as the valve functions. The second capacitor is not affected and therefore serves as a reference capacitor, i.e to compensate for operating conditions such as temperature etc.