Pressure transducer

Claim 1

A MULTIPLE-STAGE PRESSURE TRANSDUCER, COMPRISING A CASING FORMING A CHAMBER HAVING AN APERTURE AT ONE END THROUGH WHICH FLUID MAY PASS, A FLEXIBLE DIAPHRAGM WITHIN SAID CHAMBER COVERING SAID APERTURE, A MOVABLE SHAFT WITHIN SAID CHAMBER HAVING A PLATFORM ATTACHED AT ONE END, A BELLOWS SURROUNDING SAID SHAFT AND YIELDABLY SUPPORTING SAID PLATFORM AND SAID MOVABLE SHAFT, BUT ONLY IN PART, WHEN SAID PRESSURE TRANSDUCER IS BELOW SEA LEVEL, A STRETCHABLE TAPE SUSPENDED FROM SAID CASING SURROUNDING AND SUPPORTING SAID BELLOWS, A BENDING PLATE SUPPORTED BY SAID CASING AND SUPPORTING, IN PART, SAID MOVABLE SHAFT WHEN SAID PRESSURE TRANSDUCER IS BELOW SEA LEVEL, FILTERING MEANS DISPOSED BETWEEN SAID MOVABLE SHAFT AND SAID BENDING PLATE FOR TRANSMITTING ONLY AXIAL MOVEMENT OF SAID MOVABLE SHAFT TO SAID BENDING PLATE, SAID FILTERING MEANS BEING ADJUSTABLE TO A ZERO PRESSURE SETTING ON SAID BEINDING PLATE, AT LEAST ONE STRAIN GAUGE ATTACHED TO SAID BENDING PLATE FOR MEASURING THE DEFLECTION OF SAID SENSITIVE BENDING PLATE, MEANS FOR LOCKING SAID FILTERING MEANS IN A LOWEST POSITION THEREBY SHIELDING SAID BENDING PLATE FROM FURTHER PRESSURE INCREASES, RESILIENT MEANS DISPOSED BETWEEN SAID MOVABLE SHAFT AND SAID FILTERING MEANS PERMITTING THE FUTHER DESCENT OF SAID MOVABLE SHAFT ONCE SAID FILTERING MEANS HAS BEEN LOCKED IN POSITION, AND AT LEAST ONE STRAIN GAUGE ATTACHED TO SAID STRETCHABLE TUBE FOR MEASURING THE MAGNITUDE OF THE DEFLECTION OF SAID TUBE OVER A WIDE RANGE OF FLUID PRESSURES.