Apparatus for measuring and recording pressures indicated by manometer tubes

Claim 1

APPARATUS FOR RAPIDLY MEASURING AND RECORDING DIFFERENTIAL PRESSURES BY MEANS OF NON-CONDUCTIVE MANCOMTER TUBE HAVING FIRST AND SECOND BRANCHES AND CONTAINING A CONDUCTIVE FLUID COMPRISING: A FIRST CONDUCTIVE COATING ON THE OUTER CIRCUMFERENCE OF SAID FIRST BRANCH, SAID FIRST CONDUCTIVE COATING AND SAID CONDUCTIVE FLUID COMPRISING A FIRST CAPACITOR; A SECOND CONDUCTIVE COATING ON THE OUTER CIRCUMFERENCE OF SAID SECOND BRANCH, SAID SECOND CONDUCTIVE COATING AND CONDUCTIVE FLUID COMPRISING A SECOND CAPACITOR; COUPLING MEANS CONNECTED TO SAID CONDUCTIVE FLUID; A VARIABLE CAPACITOR HAVING FIRST AND SECOND STATORS AND A COMMON ROTOR, SAID FIRST STATOR AND SAID COMMON ROTOR COMPRISING A THIRD CAPACITOR, SAID SECOND STATOR AND SAID COMMON ROTOR COMPRISING A FOURTH CAPACITOR, SAID CAPACITORS BEING CONNECTED TOGETHER TO FORM A BRIDGE CIRCUIT; A NULL DETECTOR TO INDICATE BRIDGE CIRCUIT BALANCE CONNECTING SAID COUPLING MEANS TO SAID ROTOR; A ROTATABLE SHAFT MECHANICALLY COUPLED TO SAID ROTOR, MEANS TO ROTATE SAID SHAFT, THE ROTATION OF SAID SHAFT VARYING THE CAPACITANCE OF SAID THIRD AND FOURTH CAPACITORS IN OPPOSITE