Ultrasonic testing apparatus

Claim 1

IN ULTRASONIC INSPECTION APPARATUS FOR EXAMINING THE INTERIOR OF A HOLLOW MEMBER, THE COMBINATION COMPRISING A PLURALITY OF ACOUSTICAL ENERGY TRANSDUCERS POSITIONED SUBSTANTIALLY IN A PLANE AND JUXTAPOSED TO AT LEAST PARTIALLY SURROUND THE MEMBER BEING INSPECTED, AT LEAST TWO OF SAID TRANSDUCERS BEING DISPOSED FACING EACH OTHER AN OPPOSITE SIDES OF THE MEMBER AND A THIRD TRANSDUCER INTERMEDIATELY DISPOSED BETWEEN SAID TWO TRANSDUCERS, EACH OF SAID TRANSDUCERS BEING OPERATIVE TO TRANSMIT AN ACOUSTIC ENERGY PULSE INTO THE MEMBER SUBSTANTIALLY NORMALLY TO ITS OUTER SURFACE WHEN SAID EACH TRANSDUCER IS ELECTRICALLY ENERGIZED, AND TO PROVIDE AN ELECTRICAL OUTPUT SIGNAL IN RESPONSE TO REFLECTED ACOUSTIC ENERGY PULSES RECEIVED FROM THE MEMBER; PULSE GENERATING MEANS FOR ENERGIZING SAID PLURALITY OF TRANSDUCERS, SAID OPPOSITELY DISPOSED TRANSDUCERS BEING ENERGIZED SIMULTANEOUSLY AND SAID INTERMEDIATE TRANSDUCER BEING SUBSEQUENTLY ENERGIZED AFTER A TIME SUFFICIENT TO PRECLUDE ANY SUBSTANIAL INTERFERENCE OF REFLECTED ACOUSTIC ENERGY FROM A PREVIOUSLY APPLIED ENERGIZING PULSE; SEPARATE OUTPUT CIRCUIT MEANS CONNECTED EACH TO A DIFFERENT TRANSDUCER; AND SEPARATE GATING MEANS CONNECTED BETWEEN SAID PULSE GENERATING MEANS AND SAID OUTPUT CIRCUIT MEANS CONNECTED TO EACH TRANSDUCER, WHEREBY EACH OF SAID GATING MEANS CONDITIONS EACH OF SAID OUTPUT CIRCUIT MEANS TO BE RESPONSIVE TO ELECTRICAL SIGNALS DERIVED FROM REFLECTIONS OF ACOUSTIC ENERGY CAUSED BY THE ASSOCIATED ONE OF PREVIOUS ENERGIZATION OF THE ASSOCIATED ONE OF SAID TRANDUCERS CONNECTED THERETO.