Pressure measuring instrument for high static pressure atmospheres

Claim 1

A DIFFERENTIAL PRESSURE MEASURING INSTRUMENT FOR MEASURING RELATIVELY SMALL DIFFERENCES BETWEEN FIRST AND SECOND HIGH STATIC PRESSURE COMPRISING: A CASE HAVING A FIRST AND SECOND PRESSURE CHAMBER, A COMMON WALL SEPARATING SAID FIRST AND SECOND CHAMBER AND DEFINING SAID CHAMBER AND HAVING AN APERTURE EXTENDING THERETHROUGH A PLURALITY OF DIFFERENTIAL PRESSURE MEASURING CAPSULES, SAID CAPSULES BEING STACKED AND MOUNTED IN SAID SECOND PRESSURE CHAMBER, SAID STACKED CAPSULES BEING MOUNTED ON SAID WALL SEPARATING SAID FIRST AND SECOND CHAMBERS AND ENCLOSING SAID APERTURE SO THAT SAID APERTURE COMMUNICATES BETWEEN SAID FIRST CHAMBER AND THE INTERIOR OF SAID STACKED CAPSULES, A FIRST FITTING IN THE WALL OF SAID FIRST CHAMBER TO COUPLE SAID FIRST STATIC PRESSURE TO SAID FIRST CHAMBER TO APPLY SAID FIRST STATIC PRESSURE TO THE INTERIOR OF SAID STACKED CAPSULES THROUGH SAID FIRST CHAMBER AND SAID APERTURE IN SAID WALL, A SECOND FITTING IN SAID SECOND CHAMBER TO COUPLE SAID SECOND STATIC PRESSURE TO SAID SECOND CHAMBER AND TO APPLY SAID SECOND STATIC PRESSURE TO THE EXTERIOR OF SAID STACKED CAPSULES, INDICATOR MEANS COUPLED TO SAID STACKED CAPSULES TO INDICATE MOVEMENT OF THE UNMOUNTED END OF THE CAPSULE STACK AS THE STACKED CAPSULES EXPAND AND CONTRACT IN RESPONSE TO DIFFERENCES BETWEEN SAID FIRST AND SECOND PRESSURES APPLIED RESPECTIVELY TO THE INTERIOR AND EXTERIOR OF SAID CAPSULES, A FIRST VALVE COUPLED TO THE UNMOUNTED END OF THE CAPSULE STACK TO SEAL SAID APERTURE WHEN THE CAPSULE STACK HAS EXPANDED TO THE DESIGNED LIMIT OF EXPANSION, AND A SECOND VALVE COUPLED TO THE UNMOUNTED END OF THE CAPSULE STACK TO ENGAGE SAID SECOND FITTING TO SEAL SAID SECOND CHAMBER AGAINST PRESSURE LOSS WHEN SAID CAPSULES HAVE EXPANDED TO THE DESIGNED LIMIT OF EXPANSION, SAID SEALING OF SAID APERTURE AND SAID SECOND FITTING OCCURING SUBSTANTIALLY SIMULTANEOUSLY SO THAT, ON SUDDEN REDUCTION OF STATIC PRESSURE APPLIED TO THE SECOND CHAMBER, THE DIFFERENCE IN PRESSURE APPLIED TO THE INTERIOR AND EXTERIOR OF SAID STACKED CAPSULE WILL NOT EXCEED THE PRESSURE DIFFERENTIAL FOR WHICH THE CAPSULES ARE DESIGNED.