Ultrasonic flaw detection apparatus

Claim 2

An ultrasonic flaw detecting arrangement including, a pair of ultrasonic transducers constituting transmitters of pulsed ultrasonic energy, said transducers of said pair being so oriented on the workpiece that the beams of energy transmitted therefrom are angled toward each other so as to impinge upon and be reflected from a flaw in the workpiece, a third transducer constituting a receiver of ultrasonic energy for receiving from both of said transmitters reflections of the pulsed ultrasonic energy reflected from the flaw in the workpiece, means connecting the three transducers in a predetermined spaced relationship and permitting movement of said three transducers over the surface of the workpiece while maintaining said predetermined relationship to vary thereby the path length of the pulsed energy between the flaw and each of the three transducers, whereby movement of said three transducers to a position where the path lengths of the pulsed energy from each said transmitting transducer respectively to the flaw and thence to said receiving transducer are equal so as to result in superimposition of the two reflected signals at said receiving transducer and to provide thereby a flaw-responsive signal having an improved signal-to-noise ratio, and means responsive to said superimposed reflection signals.

Claim 3

Ultrasonic flaw detecting apparatus including, a pair of ultrasonic transducers constituting receivers of pulsed ultrasonic energy, a third transducer constituting a transmitter of ultrasonic energy, said transducers of said pair being so oriented on the workpiece that each is responsive to the pulsed ultrasonic energy from said transmitting transducer impinging upon a flaw in the workpiece and reflected therefrom to said receiving transducers, means connecting the three transducers in a predetermined spaced relationship and permitting movement of said three transducers over the surface of the workpiece while maintaining said predetermined relationship to vary thereby the path length of the pulsed energy between the flaw and each of the three transducers, whereby movement of said three transducers to a position where the path length of the pulsed energy from said transmitting transducer to said flaw and thence to a first of said receiving transducers equals the path length from said transmitting transducer to said flaw and thence to the second of said receiving transducers so as to result in concurrent reception of reflections from said flaw by both said receiving transducers, and means responsive to said signals received concurrently by both said receiving transducers to provide thereby a flaw-responsive signal having an improved signal-to-noise ratio.

Claim 4

Ultrasonic flaw detecting apparatus including, a pair of ultrasonic transducers constituting receivers of pulsed ultrasonic energy, a third transducer constituting a transmitter of ultrasonic energy, said transducers of said pair being so oriented on the workpiece that each is responsive to the pulsed ultrasonic energy from said transmitting transducer impinging upon a flaw in the workpiece and reflected therefrom to said receiving transducers, means connecting the three transducers in a predetermined spaced relationship and permitting movement of said three transducers over the surface of the workpiece while maintaining said predetermined relationship to vary thereby the path length of the pulsed energy between the flaw and each of the three transducers, whereby movement of said three transducers to a position where the path length of the pulsed energy from said transmitting transducer to said flaw and thence to a first of said receiving transducers equals the path length from said transmitting transducer to said flaw and thence to the second of said receiving transducers so as to result in concurrent reception of reflections from said flaw by both said receiving transducers, and means responsive to said signals received concurrently by both said receiving transducers to provide thereby a flaw-responsive signal having an improved signal-to-noise ratio.

Claim 5

An ultrasonic flaw detecting arrangement including, a pair of ultrasonic transducers constituting transmitters of pulsed ultrasonic energy, a third transducer constituting a receiver of ultrasonic energy for receiving from both of said transmitters reflections of the pulsed ultrasonic energy reflected from a flaw in a test piece, means connecting the three transducers in a predetermined spaced relationship, variable delay time Means for delaying the output pulses from one of said transmitters to cause the respective wave fronts of said pair of transmitters to arrive at a flaw simultaneously so that the reflections of said wave fronts received by the receiver are superimposed in additive interference to provide an improved signal-to-noise ratio, and means responsive to the superimposed reflections from said flaw received by said receiver.

Claim 6

An ultrasonic flaw detecting arrangement including, a pair of ultrasonic transducers constituting transmitters of pulsed ultrasonic energy, a third transducer constituting a receiver of ultrasonic energy for receiving from both of said transmitters reflections of the pulsed ultrasonic energy reflected from a flaw in a test piece, means connecting the three transducers in a predetermined spaced relationship, variable delay time Means for delaying the output pulses from one of said transmitters to cause the respective wave fronts of said pair of transmitters to arrive at a flaw simultaneously so that the reflections of said wave fronts received by the receiver are superimposed in additive interference to provide an improved signal-to-noise ratio, and means responsive to the superimposed reflections from said flaw received by said receiver.

Claim 7

An ultrasonic flaw detecting arrangement including, a pair of ultrasonic transducers constituting receivers for receiving pulsed ultrasonic energy, a third transducer constituting a transmitter of pulsed ultrasonic energy, means connecting the three transducers in a predetermined spaced relationship, the receivers being arranged to receive reflections of the pulsed ultrasonic energy reflected from a flaw in a test piece, means responsive to the reflection signals received by both said receivers, and variable time delay means for delaying the reflection signal supplied to said responsive means from one said receiver so as to permit superimposition of the reflection signals from said two receivers in additive interference at said responsive means to provide thereby an improved signal-to-noise ratio.

Claim 8

An ultrasonic flaw detecting arrangement including, a pair of ultrasonic transducers constituting receivers for receiving pulsed ultrasonic energy, a third transducer constituting a transmitter of pulsed ultrasonic energy, means connecting the three transducers in a predetermined spaced relationship, the receivers being arranged to receive reflections of the pulsed ultrasonic energy reflected from a flaw in a test piece, means responsive to the reflection signals received by both said receivers, and variable time delay means for delaying the reflection signal supplied to said responsive means from one said receiver so as to permit superimposition of the reflection signals from said two receivers in additive interference at said responsive means to provide thereby an improved signal-to-noise ratio.

Claim 9

The combination of claim 2 which further includes, a second pair of receiving transducers, said transducer of said first pair being placeable on the workpiece symmetrically to either side of said third transducer, said transducers of said second pair being placeable on the workpiece symmetrically to either side of said third transducer and being also spaced outwardly of said transducers of said first pair, said transducers of said first pair having their directivity axes directed toward each other at a large angle to a normal to the surface of the workpiece so as to intersect at a shallow level below the surface of the workpiece, said transducers of said second pair having their directivity axes directed toward each other at a smaller angle to said normal so as to intersect at a deeper level below the surface of the workpiece.