ULTRASONIC GAS FLOWMETERS

Ultrasonic contrapropagation flowmeters for gases have been used successfully in a wide variety of applications. During the past dozen years or so for example, several manufacturers have solved major pow problems in pare gas, natural gas, and in CEM (continuous emissions monitoring) of gas exiting smokestacks and vents. This article compares ultrasonic gas and liquid flowmeters. Opportunities exist for ultrasonic gas meters to measure not only pow velocity but also average molecular weight, density, concentration, and mass flow rate. These opportunities occur in applications in ducts ranging from a few millimeters to several meters in. diameter; in flows from 1 cm/s to the order of 100 m/s; from low temperatures up to 500 degrees C using a recently-developed one- or two-part buffer rod; and pressure from below 1 bar up to 300 bar (4500 psig).