Temperature compensated pressure indicator

Claim 1

A PRESSURE INDICATOR COMPRISING A TUBULAR HOUSING HAVING A CLOSED END AND AN OPEN END, A CLOSURE FOR SEALING SAID OPEN END HAVING AN OPENING FOR FLUID FLOW CONNECTION OF SAID HOUSING TO A RECEPTACLE CONTAINING A GASEOUS MEDIUM UNDER PRESSURE TO BE MONITORED, A TUBULAR CASING IN SAID HOUSING FOR CONTAINING A CONSTANT MASS OF GASEOUS MEDIUM UNDER PRESSURE HAVING A WALL AT ONE END SECURED TO SAID CLOSURE AND HAVING A TUBULAR WELL AT ITS OTHER END EXTENDING AXIALLY TOWARDS SAID WALL AND PROVIDED WITH AN OPEN INNER END FACING SAID WALL, A TUBULAR PRESSURE RESPONSIVE ELEMENT IN SAID WELL HAVING AN OPEN INNER END SEALED WITHIN THE OPEN INNER END OF SAID WELL AND HAVING A CLOSED OUTER END EXTENDING OUTWARDLY OF SAID WELL, WHEREBY THE CONSTANT MASS OF GASEOUS MEDIUM IS CONFINED WITHIN SAID CASING AND SAID ELEMENT AND SAID ELEMENT IS MOVABLE IN RESPONSE TO PRESSURE CHANGES OF THE GASEOUS MEDIUM IN SAID HOUSING, AND AN INDICATOR MEMBER SECURED TO SAID PRESSURE RESPONSIVE ELEMENT FOR MOVEMENT THEREWITH, SAID HOUSING BEING CONSTRUCTED AND ARRANGED FOR VIEWING SAID INDICATOR MEMBER.