PNNL

Abstract

An ultrasonic sensor has been developed in which 1) the transducer is bonded to the stainless steel pipeline wall, possibly as part of a spool piece or 2) a separate clamp-on sensor is fastened to the stainless steel pipeline. In either case, the stainless steel acts as part of the sensing system, in which ultrasound is reflected at the interface between the pipeline wall and the liquid or slurry. A method will be described in which the acoustic impedance of the liquid (defined as the density of liquid multiplied by the speed of sound in liquid) is determined. By using a time-of-flight method, the speed of sound is determined which, in turn, yields the density. The self-calibrating feature of the sensor will also be described in which fluctuations in the pulser voltage applied to the transducer do not affect the measurement. A U.S. patent application has bgeen filed for this sensor.