Pressure Measuring Instrument

摘要

A pressure sensor (40) useful as a vacuum manometer. A reference pressure cavity (50) of the sensor is evacuated through an evacuation opening (72) located behind a plate portion (54) of the sensor electrode (52) having a non-planar surface for supporting the diaphragm (44) during an overpressure event. The electrode is hermetically sealed to the body (42) of the sensor by a brazed joint with a ceramic seal member (60) disposed there between. The brazed joint may include a layer of buffer material (79) which provides a degree of malleability to the joint to avoid cracking of the ceramic seal member. The brazed ceramic/metal joint permits the selection of materials such that differential thermal expansion effects can be passively minimized. The electrode is connected to the sensor circuitry (84) by a wire having a spring section (53), thereby providing a stress free interconnection.