As a new coming technique in the gas flow measure area, Ultrasonic flowmeters (USF) are just becoming the most favorite selection, special for the nature gas transport project. Due to the accuracy, stability, no pressure loses, wide measure range, and low cost, the Ultrasonic flowmeters just show its competitions.USF can be used to measure the gas and liquid both, there are same theories: Ultrasonic flow meters determine the fluid velocity by transmitting pulse stream upwards and downwards and measuring the...