An ultrasonic non-destructive testing apparatus utilizing through transmission water jet coupling. Through transmission is provided along an arcuate path which includes paired exit path portions of the apparatus. Sound is transmitted through the bent liquid column via transmitting and receiving transducers upstream of the respective paired exit path portions.
An ultrasonic water jet having first and second housing members. The first housing member includes an interior exponentially shaped duct and a plurality of water inlets equiangularly displaced and circumferentially disposed about the central axis of the exponentially shaped duct for cleansing a face of the ceramic disk transducer clamped between the first housing member and an O-ring seated in the second housing member.