Abstract: An ultrasonic transducer assembly for monitoring the quality of spot welds employs a transducer element joined to a support element and fitted within a conventional welding electrode assembly. The transducer assembly is biased against the interior surface of the welding electrode tip by a biasing element, preferably a compression spring. A sleeve, preferably composed of brass, surrounds the transducer element and is joined to the support element. A coaxial cable in communication with external instrumentation has a ground lead attached to the sleeve, and a signal lead attached to the transducer element.

Abstract: An ultrasonic transducer assembly for making measurements within a fluid, the assembly including a transducer, a backing member and a matching member all supported within a cylindrical metal housing with the transmitting face of the housing being sealed with a thin sealing element formed of a non-resilient relatively high impedance material encasing a matching layer having an acoustic impedance intermediate between that of the transducer element and the fluid. The thickness of the sealing element is between 1/10 and 1/1000th of a wavelength at the center frequency of the wave emitted by the transducer.