#Ultrasonic flow meters use high-frequency sound waves, above 25 kHz, for accurate measurements without audible noise, generated by vibrating piezoelectric crystals. An ultrasonic flow meter consists of at least one sensor and transducer pair. Each member of the pair can act both as a transmitter and a receiver. When in receive mode, an ultrasonic wave passing through the fluid creates vibration in the piezoelectric crystal, and an electrical impulse is generated. When in transmit mode, an oscil