Stall-surge sonic sensor and control apparatus for turbo-compressor type gas engines

Claim 1

IN A GAS TURBINE POWER PLANT HAVING AN AXIAL FLOW COMPRESSOR HAVING LOW PRESSURE AND HIGH PRESSURE STAGES AND A FUEL FLOW CONNTROL VALVE, IN WHICH SAID COMPRESSOR GENERATES DISCRETE SONIC FREQUENCIES VARYING IN ACCORDANCE WITH THE OPERATING RANGE OF SAID COMPRESSOR AND CHARACTERIZED BY THE DEVELOPMENT OF A PREDETERMINED NUMBER OF PERIODICALLY RECURRING PULSES IN THE SONIC FREQUENCIES WHEN SAID COMPRESSOR APPROACHES AN OPERATING RANGE CAUSING STALL TO SURGE CONDITIONS THEREIN, A MICROPHONE MOUNTED ON SAID POWER PLANT ADJACENT SAID LOW PRESSURE STAGES OF SAID COMPRESSOR TO RECEIVE AND DEVELOP INPUT SIGNALS CORRESPONDING TO THE SONIC FREQUENCIES AND PULSES GENERATED IN THE LOW PRESSURE STAGES OF SAID COMPRESSOR, A CONTROL CIRCUIT ELECTRICALLY INTERCONNECTED BETWEEN SAID MICROPHONE AND SAID FUEL FLOW CONTROL VALVE INCLUDING MEANS TO AMPLIFY SAID SIGNALS WITH AN AUDIO FILTER FOR SELECTIVELY PASSING SAID SIGNALS WITHIN A FREQUENCY RANGE INCLUDING SAID PULSES GENERATED AND A THYRATRON CIRCUIT HAVING A VARIABLE TIME CONSTANT INCLUDING A DISCRIMINATOR RESPOSIVE TO PULSES HAVING THE PULSE RAPIDITY RATE ACCOMPANYING STALL AND SURGE CONDITIONS PASSING THROUGH SAID FILTER TO ENERGIZE SAID THYRATRON AND RELAY MEANS ENERGIZABLE BY SAID THYRATRON AND CONNECTED TO SAID FUEL FLOW CONTROL VALVE TO ADJUST THE SAME IN RESPONSE TO THE ENERGIZATION OF SAID THYRATRON TO CONTROL THE RATE OF FUEL CONSUMPTION OF SAID POWER PLANT TO PREVENT THE PROGRESSION OF STALL AND SURGE CONDITIONS IN SAID COMPRESSORR.