Acoustical analyser for indicating component malfunction of high-speed engines and the like

Claim 1

AN ENGINE SONIC ANALYSER SYSTEM FOR DETECTING MECHANICAL FAULTS IN ROTATING PARTS OF A HIGH-SPEED ENGINE RUNNING AT OR NEAR A PREDETERMINED REFERENCE R.P.M., COMPRISING ACOUSTICAL MEANS POSITIONED IN AIR-SPACED, SEPARATELY MOUNTED RELATION TO THE ENGINE FOR PRODUCING ELECTRICAL SIGNALS REPRESENTING SOUND SPECTRUM ENERGY RADIATED FROM ONE OR MORE SELECTED REGIONS OF THE ENGINE, SAID SPECTRUM SIGNALS INCLUDING AN ELECTRICAL REFERENCE SIGNAL OF FREQUENCY THAT IS CHARACTERISTIC OF A GIVEN ENGINE PART ROTATING IN DIRECT RELATION TO THE ENGINE R.P.M. AND A DISCRETE SIGNAL OF FREQUENCY THAT IS CHARACTERISTIC OF AN ENGINE PART SELECTED FOR TEST, AND ELECTRONIC ANALYSING MEANS HAVING NO MECHANICAL OR ELECTRICAL CONNECTION WITH THE ENGINE, FOR RECEIVING ALL THE AFORESAID SOUND SPECTRUM SIGNALS AND PRODUCING INFORMATION FOR REPRESENTING THE ACTUAL OPERATIVE CONDITION OF THE SELECTED TEST PART AS COMPARED WITH KNOWN DATA ON A NORMAL COUNTERPART, SAID ANALYSING MEANS CONSTITUTING ELECTRONIC CIRCUITRY DEFINING A DATA SIGNAL CHANNEL AND A CONTROL SIGNAL CHANNEL FOR PROCESSING THE SOUND SPECTRUM SIGNALS, THE DATA CHANNEL INCLUDING A BALANCED MODULATOR HAVING A FIRST INPUT FOR THE SOUND SPECTRUM SIGNALS, THE CONTROL CHANNEL CONSTITUTING ELECTRONIC CIRCUITRY INTERCONNECTING THROUGH A SEPARATE BRANCH SAID ACOUSTICAL MEANS AND A SECOND INPUT OF SAID BALANCED MODULATOR AND HAVING MEANS FOR PRODUCING FROM THE SOUND SPECTRUM SIGNALS, INCLUDING SAID SIGNAL REPRESENTING ACTUAL R.P.M. OF THE ENGINE, A TRACKING SIGNAL CORRECTED FOR DEVIATION OF ENGINE R.P.M. FROM THE REFERENCE R.P.M. SAID TRACKING SIGNAL BEING FED TO SAID SECOND INPUT OF THE BALANCED MODULATOR FOR MIXING WITH SAID FIRST INPUT SPECTRUM SIGNALS, AND AN INTERMEDIATE-FREQUENCY FILTER FOR SELECTING FROM THE MODULATED BALANCED MODULATOR SIGNAL OUTPUT OF THE MIXER A PURE TONE SIGNAL REPRESENTING THE DISCRETE TEST SIGNAL CORRECTED FOR R.P.M. DEVIATION, AND A DISPLAY INDICATOR RESPONSIVE TO SAID PURE TONE SIGNAL FOR VISUAL MANIFESTATION OF THE OPERATIVE CONDITION OF THE SELECTED TEST PART AS COMPARED WITH A NORMAL COUNTERPART.