Media independent differential pressure transducer

Abstract

A differential pressure transducer utilizing fluid-filled chambers as pressure transfer linkage to an isolated, fluid-filled aneroid sensing system. Isolation diaphragms are spread by means of internal fluid pressure fill of transfer chambers, thus providing elevated line pressure mode and pressure-biased operation. Construction offers media isolation from sensitive interior elements of the transducer. Material to come into physical contact with a pressure medium may thus be chosen for specific application. Dual, nested aneroid sensors cooperated to produce a linear displacement in response to an applied pressure differential. A cantilever beam assembly responds to the linear displacement so caused by flexing in a degree proportional to the applied pressure differential. The fluid-filled sensing system may comprise nested, aneroid capsule diaphragms, carrying a sufficient amount of incompressible fluid to support the capsule diaphragm for high line pressure use. The nested, aneroid capsule diaphragms are thus also spread by the fluid pressure, thereby placing the pressure deflection of the aneroids in an elevated line pressure mode and providing pressure-biased operation. Strain gages respond to the flexing of the cantilever beam assembly, thereby having an electrical signal induced in them proportional to the applied differential pressure as sensed by the aneroid capsule diaphragm sensors.