| 摘要 |
PURPOSE:To reduce span errors owing to static pressure, temp. and tightening and to improve protective performance against overpressure by such constitution wherein a bellows is used for a pressure receiving element and when said element is overloaded, stop bars contact an O-ring and inhibit the movement of sealed liquids. CONSTITUTION:When a high measuring pressure PH is introduced through an introducing hole 611 into a measuring chamber 61 and a low measuring pressure PL is introduced through an introducing hole 711 into a measuring chamber 71, the pressures there of are transmitted to sealed liquids 4, 5 with sealing diaphragms 23, 24. The pressures thereof are converted to forces by the front and rear surfaces of a bellows 11, which forces move the electrode 12 at the preceding end of the bellows 11 rightward, thereby decreasing the electric capacity between the electrodes 12 and 16 and increasing the electric capacity between the electrodes 12 and 17. A differential pressure is thus detected. Since the bellows 11 is used as a differential pressure element and strains are absorbed in the cylindrical part of the bellows end, span errors owing to static pressure, tightening and temp. are reduced. When the element is overloaded, stoppers 18, 19 contact an O-ring 29 and inhibit the movement of the liquids 4, 5; therefore the protective performance against overpressure is good. |
