HIGH OVERPRESSURE LOW RANGE PRESSURE SENSOR

摘要

A low range pressure sensor (10) includes a base plate of brittle material (12), and a diaphragm plate assembly (14) mounted on the base plate (12) and sealed around a periphery (16) to the base plate (12). Pressures are introduced to cause a center diaphragm section (18) to deflect toward the base plate (12), and the deflection of the diaphragm (18) is sensed through strain gauges (32) to provide an indication of the pressure. The diaphragm (18) is provided with a plurality of individual support posts (36) on a side facing the base plate (12), so that when the diaphragm (18) is deflected toward the base plate (12) under high overpressures the support posts (36) will support the diaphragm (18) against movement to avoid failure or breakage of the diaphragm (18). The number of support posts (36) can be varied as desired. In a preferred form of the invention, the base plate is provided with a very thin layer (40) of silicon dioxide, which is a good electrical insulator and which also serves to help accommodate slight movement of the support posts (36) as they touch the surface of the base plate (12) to reduce stress buildup in the diaphragm (18) as the overpressure increases.