Pressure difference compensated torsion tube - is used to transfer measurement force between volumes using strain gauges and sensing

摘要

A torsion tube device is for transfer of a measurement force from one volume to another where the volumes are at different pressures. It is designed to compensate errors due to the press. difference. The device may be used in fluid level measurement where the position of a float is converted into a rotation of the tube which is measured externally by optical, electrical, or pneumatic methods. The tube (3) is a hollow cylinder (3) with its open end (4) fitted into a seal in an opening (1) in the wall (2) separating the volumns. The measurement force (K) applies torque to the sealed tube end (5). Strain gauges (7, 7') placed at 45 degrees to the tube axis on or in the tube are connected in a circuit so as to compensate the static press (P1) signal component.