Ultrasonic testing apparatus

Claim 1

IN APPARATUS FOR THE ULTRASONIC NON-DESTRUCTIVE TESTING OF LENGTHS OF PIPE HAVING ACCESSIBLE ENDS TO DETERMINE THE EXISTENCE OF FLAWS THEREIN, FIRST AND SECOND WAVE DIRECTOR ASSEMBLIES ADAPTED FOR ENGAGING OPPOSITE ENDS OF THE PIPE, EACH OF SAID WAVE DIRECTOR ASSEMBLIES INCLUDING A PLURALITY OF WAVE DIRECTORS, EACH OF SAID WAVE DIRECTORS COMPRISING A BODY HAVING AN OUTPUT SURFACE ADAPTED TO ENGAGE THE END OF THE PIPE AND AN INPUT SURFACE SPACED FROM THE OUTPUT SURFACE, THE BODY OF EACH OF SAID WAVE DIRECTORS HAVING AN ATTENUATING PORTION ADJOINING THE REGION BETWEEN THE INPUT AND OUTPUT SURFACES, A TRANSDUCER FOR EACH WAVE DIRECTOR, EACH OF THE TRANSDUCERS MOUNTED TO PASS ULTRASONIC WAVE TRAINS THROUGH THE BODY OF THE WAVE DIRECTOR AND THROUGH THE INPUT SURFACE, THE WAVE DIRECTORS BEING FURTHER CONSTRUCTED SO THAT EACH WAVE DIRECTOR TRANSMITS OR RECEIVES ULTRASONIC WAVE TRAINS AT A SUBSTANTIAL ANGLE TO THE OUTPUT SURFACE, EACH OF SAID FIRST AND SECOND WAVE DIRECTOR ASSEMBLIES HAVING MEANS FOR MOUNTING THE WAVE DIRECTORS IN AN ARRAY IN WHICH THE OUTPUT SURFACES LIE FACING IN A SINGLE DIRECTION AND ARE ADAPTED TO CONFORM TO THE SHAPE OF THE END OF THE PIPE, THE WAVE DIRECTORS IN THE ARRAY BEING ARRANGED SO THAT THE OUTPUT SURFACES THEREOF ARE SPACED APART AND THEREFORE ADAPTED TO ENGAGE SPACED APART PORTIONS ABOUT THE END OF THE PIPE, THE WAVE DIRECTORS WITHIN EACH ARRAY BEING SIMILARLY POSITIONED WITH RESPECT TO THE WALL OF THE PIPE, THE TANGENT TO THE WALL OF THE PIPE BEING TAKEN AS A REFERENCE, THE WAVE DIRECTORS OF ONE ASSEMBLY TRANSMITTING OR RECEIVING ULTRASONIC WAVE TRAINS THROUGH THE PIPE IN HELICAL DIRECTION OPPOSITE TO THAT OF THE OTHER ASSEMBLY, MEANS FOR ENERGIZING THE TRANSDUCERS ON ONE OF SAID ASSEMBLIES FOR GENERATING ULTRASONIC WAVE TRAINS WHICH ARE INTRODUCED INTO THE PIPE AND TRAVEL IN HELICAL PATHS, FLAWS IN THE PIPE REFLECTING SOME WAVE TRAINS INTO AN OPPOSITE DIRECTION AND THEREFORE RECEIVABLE BY ONE OF THE WAVE DIRECTORS OF SAID OTHER WAVE DIRECTOR ASSEMBLY, MEANS FOR PROVIDING AN INDICATION WHEN ANY OF SAID OTHER WAVE DIRECTORS RECEIVE SUCH REFLECTED HELICAL WAVE TRAINS.