Ultrasonic transmitter-receiver and ultrasonic flowmeter

摘要

An ultrasonic transducer according to the present invention includes: a piezoelectric body 4 to set up ultrasonic vibrations; an acoustic matching layer 3 made of a material with a density of 50 kg/m<3 >to 1,000 kg/m<3 >and an acoustic impedance of 2.5x10<3 kg/m><2>/s to 1.0x10<6 >kg/m<2>/s; a lower acoustic matching layer 9 provided between the piezoelectric body 4 and the acoustic matching layer 3; and a structure supporting member 6 that supports the lower acoustic matching layer 9 and the piezoelectric body 4 thereon and shields the piezoelectric body 4 from a fluid that propagates the ultrasonic vibrations. The ultrasonic transducer includes a protective portion, which contacts with at least a portion of a side surface of the acoustic matching layer 4. This protective portion is defined by a portion of the lower acoustic matching layer 9 and forms an integral part of the lower acoustic matching layer 9.