Patent ID: 8104341

Claim:
An ultrasonic transducer unit externally mountable to a tank wall and operable to measure a liquid level inside a tank, comprising: an emitter to generate an ultrasonic beam to pass through a tank wall and to receive an echo of the ultrasonic beam off a liquid surface inside the tank; a transducer driver in electrical communication with the emitter; an acoustic lens coupled to the emitter and including a convex outer surface and configured to shape the ultrasonic beam and configured to diverge the ultrasonic beam and thereby provide an ultrasonic beam with a uniform wavefront after the ultrasonic beam passes through a tank wall; and an acoustic coupler disposed adjacent the acoustic lens and including, a first concave surface to receive the convex outer surface of the acoustic lens, and a second concave surface to compliment the curvature of the tank wall, wherein the acoustic coupler is configured to increase transmission of the ultrasonic beam to the interface with the tank wall.