Acoustic velocity measurement of slow moving media - using periodically interchanged piezo transducers operating at HF

摘要

The measurement of the velocity of movement of a medium is based on measurement of sound waves transmitted between two identical single-crystal quartz transducers immersed in the medium. The electrical connections to the transducers have similar phase characteristics up to gigahertz frequencies and are periodically reversed at a rapid rate. A transducer head has a quartz piezo-electric transducer which acts as a piston generator mounted on a shoulder in a ball-shaped metal head. A hollow chamber inhibits back radiation. Electrodes are provided for the electrical connections to the piezo transducer which is fed through a tubulr hole. A thick, piezo-inactive window permits acoustic coupling to the medium. O-rings seal the transducer against ingress of sea water and permit operation at great depths.