THREE-FORCE BALANCING TYPE INSTRUMENT

摘要

PURPOSE:To elevate the measuring accuracy by providing a spring which is adapted to impart an energizing force in the direction of a turning force derived from a displacement due to a differential pressure of two seal diaphragms. CONSTITUTION:A third action member 23 is added in contact with an arc surface of a floating fulcrum 9 and applied between the fulcrum and the other end 28 thereof to be fixed at three points. A tension F'3 working on the member 23 oscillates the first action member 10 counterclockwise to apply a reaction so that pressure receiving diaphragms 3 and 4 are displaced counterclockwise (or the high pressure HP side) through a pressure drawing bar 7 and a strup 8. Then, a bias spring 30 which has a force roughly equivalent to a tension F'3 at the member 23 is provided in the direction of oscillating the drawing bar 7 clockwise against such a reaction to prevent the counterclockwise movement of the diaphragms 3 and 4. In this manner, the reaction due to tension or the like is prevented from affecting the diaphragms 3 and 4 thereby elevating the measuring accuracy.