Ultrasonic inspection apparatus

Claim 2

In an ultrasonic nondestructive material tester for testing a workpiece a transmitting transducer including: a plurality of pairs of spaced electrodes forming a current path therebetween, each said pair of said plurality being aligned with one another and spaced a predetermined distance between one another; an electrically conductive fluid being disposed between the current paths of said pairs of electrodes; means coupled to said plurality of pairs of electrodes for sequentially applying a potential to said plurality of pairs of electrodes for causing a current to flow sequentially between each pair of such plurality: and means for limiting the current flow between said plurality of pairs of electrodes to a level below the arcing point thereof whereby each pair of said plurality of pairs of electrodes has current flow therebetween timed to occur as the ultrasonic wave flow travels across each current path.

Claim 3

A nondestructive tester for testing a workpiece, said tester including the combination of: a transducer having a pair of electrodes electrically separated from each other by spaced current path; an electrically conductive fluid between the electrodes of said pair filling said path, the fluid being sufficiently electrically conductive to allow current to flow between said pair of electrodes when the voltage across said pair of electrodes is less than a predetermined breakdown voltage level; pulse means coupled across the electrodes in said transducer for applying a voltage across said pair of electrodes which is below the breakdown voltage of said path, said pulse means being effective to produce an electrical current between the electrodes and through the electrically-conductive fluid, whereby ultrasonic energy is transmitted toward the workpiece; at least one additional pair of electrodes effective to form at least one additional spaced current path, the current paths being separated from each other by a predetermined distance; and said pulse means being effective to circulate pulses of current sequentially across said spaced current paths, whereby ultrasonic energy is produced in each path, said pulse means being effective to circulate said current pulses at intervals which are substantially coincident with the intervals required for the ultrasonic energy to travel said predetermined distances.

Claim 4

A nondestructive tester for testing a workpiece, said tester including the combination of: a transducer having a pair of electrodes electrically separated from each other by spaced current path; an electrically conductive fluid between the electrodes of said pair filling said path, the fluid being sufficiently electrically conductive to allow current to flow between said pair of electrodes when the voltage across said pair of electrodes is less than a predetermined breakdown voltage level; pulse means coupled across the electrodes in said transducer for applying a voltage across said pair of electrodes which is below the breakdown voltage of said path, said pulse means being effective to produce an electrical current between the electrodes and through the electrically-conductive fluid, whereby ultrasonic energy is transmitted toward the workpiece; at least one additional pair of electrodes effective to form at least one additional spaced current path, the current paths being separated from each other by a predetermined distance; and said pulse means being effective to circulate pulses of current sequentially across said spaced current paths, whereby ultrasonic energy is produced in each path, said pulse means being effective to circulate said current pulses at intervals which are substantially coincident with the intervals required for the ultrasonic energy to travel said predetermined distances.

Claim 5

The nondestructive tester as defined in claim 2 and including receiving means effective to receive the ultrasonic energy from the workpiece.

Claim 6

The nondestructive tester as defined in claim 2, wherein the pulse means is effective to circulate a pulse of electric current across the pulsed current path which is substantially unipolar.