| 摘要 |
<p>Pneumatic pressure sensor of the kind where the pressure to be sensed acts on a diaphragm (50) which moves to control the exhaust of gas from a pressurized control chamber (20). The invention provides means for inhibiting or preventing the diaphragm from becoming overstrained. To support the diaphragm against excessive external pressure the diaphragm is mounted spaced a small distance in front of a backing plate (10); while to protect it from excessive internal pressure, firstly, mechanical stop means (62) are provided for limiting the outward movement permitted to a rod (60) fixed to the diaphragm centre, and secondly, pressure control means are provided for limiting to a predetermined extent, and relative to the pressure acting externally, the maximum gas pressure which can act upon the internal face of the diaphragm.</p> |
