Means and methods for electrically measuring the amount of oxygen in a gas

Claim 1

AN INSTRUMENT FOR ANALYZING A GASEOUS MEDIUM TO DETERMINE THE CONCENTRATION OF OXYGEN THEREIN, SAID INSTRUMENT COMPRISING A FIRST GLASS TUBE THROUGH WHICH THE GAS TO BE ANALYZED CAN FLOW CONTINUOUSLY, FIRST AND SECOND COILS WOUND IN AXIALLY SPACED RELATION ABOUT SAID TUBE, A SECOND GLASS TUBE MOUNTED WITHIN A CLOSED CONTAINER WHICH IS FILLED WITH A GAS OF KNOWN MAGNETIC PERMEABILITY, SAID SECOND TUBE BEING IN OPEN COMMUNICATION AT ITS OPPOSITE END TO THE INTERIOR OF THE CONTAINER, SO THAT THE INTERIOR OF THE SECOND TUBE IS FILLED WITH THE SAME GAS AS THAT WHICH OCCUPIES THE INTERIOR OF THE CONTAINER, THIRD AND FOURTH COILS WOUND IN AXIALLY SPACED RELATION UPON THE SECOND TUBE, SAID FIRST, SECOND, THIRD, AND FOURTH COILS ALL HAVING IDENTICAL NUMBERS OF TURNS, A SIGNAL GENERATOR, A SIGNAL ISOLATION TRANSFORMER HAVING ITS PRIMARY CONNECTED TO THE OUTPUT SIDE OF THE SIGNAL GENERATOR AND ITS SECONDARY CONNECTED IN SERIES WITH THE FIRST AND THIRD COILS, A MIXING TRANSFORMER HAVING ITS PRIMARY CONNECTED IN SERIES WITH THE SECOND AND FOURTH COILS, ITS SECONDARY CONNECTED TO THE INPUT SIDE OD A HIGH-GAIN AMPLIFER, AND INDICATOR MEANS OPERATIVELY CONNECTED TO THE OUTPUT SIDE OF THE HIGH-GAIN AMPLIFIER.