Pressure transducer

Claim 1

A PRESSURE TRANSDUCER COMPRISING: (A) A CIRCULAR DIAPHRAGM HAVING AN INTEGRALLY ATTACHED RIM, SAID DIAPHRAGM FLEXING IN RESPONSE TO PRESSURE ON THE SURFACE OF SAID DIAPHRAGM TO PRODUCE TENSION AND COMPRESSION STRAINS IN SAID DIAPHRAGM; (B) A COVER PLATE ATTACHED TO THE RIM OF SAID DIAPHRAGM TO FORM A HERMETICALLY SEALED CHAMBER BETWEEN SAID DIAPHRAGM AND SAID COVER PLATE SURROUNDED BY SAID RIM, SAID CHAMBER BEING EVACUATED; (C) A FIRST PAIR OF STRAIN GAGES, EACH COMPRISING A STRAIN SENSITIVE ELECTRICAL RESISTANCE ELEMENT, POSITIONED IN SAID HERMETICALLY SEALED CHAMBER,ATTACHED TO SAID DIAPHRAGM AND COVERING THE CENTRAL AREAL OF SAID DIAPHRAGM OUT TO ABOUT 58 PERCENT OF THE OVER-ALL RADIUS OF SAID DIAPHRAGM, EACH STRAIN GAGE OF SAID FIRST PAIR OF STRAIN GAGES OCCUPYING ABOUT ONE-HALF OF SAID CENTRAL AREA OF SAID DIAPHRAGM AND HAVING A PLURALITY OF SEMICIRCULAR ELEMENTS CONCENTRIC WITH THE CENTER OF SAID DIAPHRAGM; (D) A SECOND PAIR OF STRAIN GAGES, EACH COMPRISING A STRAIN SENSITIVE ELECTRICAL RESISTANCE ELEMENT, POSITIONED IN SAID HERMETICALLY SEALED CHAMBER, ATTACHED TO SAID DIAPHRAGM AND POSITIONED AROUND THE OUTSIDE OF SAID FIRST PAIR OF STRAIN GAGES, EACH STRAIN GAGE OF SAID SECOND PAIR OF STRAIN GAGES, EACH STRAIN PLURALITY OF ELEMENTS ARRANGED RADIALLY ON SAID DIAPHRAGM; (E) SAID FIRST AND SECOND PAIR OF STRAIN GAGES HAVING APPROXIMATELY EQUAL RESISTANCES, EACH STRAIN GAGE BEING ONE ARM OF A WHEATSTONE BRIDGE; AND (F) A SEPARATE ELECTRICAL CONDUCTOR CONNECTED TO EACH STRAIN GAGE AND PASSING THROUGH A WALL OF SAID HERMETICALLY SEALED CHAMBER TO A LOCATION OUTSIDE OF SAID HERMETICALLY SEALED CHAMBER.