Temperature measuring apparatus

Claim 1

A TEMPERATURE MEASURING APPARATUS FOR MEASURING THE TEMPERATURE WITHIN A ZONE WHICH APPARATUS COMPRISES, AN ENCLOSED GAS FILLED ACOUSTICAL RESONATOR, A FIRST ELONGAGED COUPLING TUBE HAVING AN EXTREMITY THEREOF CONNECTED TO SAID RESONATOR, A FIRST TRANSDUCER SECURED TO SAID FIRST COUPLING TUBE AT THE OTHER EXTREMITY THEREOF FOR TRANSMITTING AN AUDIO SIGNAL THROUGH SAID ACOUSTICAL RESONATOR, A SECOND ELONGATED COUPLING TUBE HAVING ONE EXTREMITY THEREOF CONNECTED TO SAID RESONATOR IN SPACED RELATION TO SAID FIRST COUPLING TUBE, A SECOND TRANSDUCER SECURED TO SAID SECOND COUPLING TUBE AT THE OTHER EXTREMITY THEREOF FOR RECEIVING THE SIGNAL TRANSMITTED THROUGH SAID ACOUSTICAL RESONATOR AND FOR PRODUCING AN ELECTRICAL SINGAL RELATED THERETO, SAID COUPLING TUBES BEING SUBSTANTIALLY SMALLER IN CROSS-SECTION THAN SAID RESONATOR AND BEING OF SUFFICIENT LENGTH OF EXTEND BEYOND SAID ZONE, MEANS SELECTIVELY VARYING THE FREQUENCY OF THE AUDIO SIGNAL TRANSMITTED THROUGH SAID ACOUSTICAL RESONTATOR UNTIL THE GAS THEREIN IS INDUCED TO OSCILLATE IN A RESONANT MODE, THE RESONANT OSCILLATION OF THE GAS BEING MANIFESTED AS A MAXINUM SIGNAL PRODUCED BY SAID SECOND TRANSDUCER, AND MEANS MEASURING THE FREQUENCY OF SAID AUDIO SIGNAL AT WHICH A RESONANT CONDITION IS INDUCED IN THE GAS SO THAT THE TEMPERATURE THEREOF CAN BE DETERMINED, THE TEMPERATURE OF THE GAS BEARING ON THE MEASURED VALUE OF THE FREQUENCY IN ACCORDANCE WITH THE FOLLOWING RELATIONSHIP: