Super User Ultrasonic Flowmeters An ultrasonic flow meter measures the velocity of a fluid with ultrasound to calculate volume flow. Sierra Ultrasonic Flow Meters InnovaSonic 207iUltrasonic Digital Liquid Flow MeterThe 207i calculates thermal energy / BTU flow energy & provides you with the highest accuracy measurements possible to manage energy costs. Learn More InnovaSonic 203Ultrasonic Liquid Flow MeterThis economical ultrasonic liquid flow meter delivers a highly accurate and repeatable flow measurement for liquids at an economical price. Learn More InnovaSonic 210Portable Transit Time Ultrasonic FlowmeterThe handheld battery powered InnovaSonic 210 is ideal for precisely measuring a wide range of liquid flows in pipes up to 6000 mm. Learn More SiteLab Ultrasonic Flow Meters SL1168Dedicated Transit Time Ultrasonic FlowmeterThe SL1168 is a universal transit-time flowmeter that has been designed using FPGA chip and low-voltage broadband pulse transmission. Learn More SL1278PPortable Transit Time Ultrasonic FlowmeterThe SL1278P replaces the SL1168P, it can reliably measure liquids containing moderate amounts of suspended solids with a SD Card for data logging. Learn More SL1188Transit Time Ultrasonic Flow MeterThe SL1188 offers low power consumption and high reliability and can be configured via the keypad without any additional programming. Learn More D118iDedicated Transit Time Ultrasonic FlowmeterThe D118i Ultrasonic Flowmeter is a universal transit-time flowmeter designed using ARM COMA technology and low-voltage broadband pulse transmission. Learn More SL1288iHandheld Ultrasonic FlowmeterThe SL1288i is a portable ultrasonic flow meter that has been designed to enable to user to measure flow checks at many points. Learn More SL3488D PlusUniversal transit Time Ultrasonic FlowmeterThe SL1168 is a universal transit-time flowmeter that has been designed using FPGA chip and low-voltage broadband pulse transmission. Learn More Ultrasonic flowmeters use sound waves to determine the velocity of a fluid flowing in a pipe. At no flow conditions, the frequencies of an ultrasonic wave transmitted into a pipe and its reflections from the fluid are the same. Under flowing conditions, the frequency of the reflected wave is different due to the Doppler effect. When the fluid moves faster, the frequency shift increases linearly. The transmitter processes signals from the transmitted wave and its reflections to determine the flow rate.Transit time ultrasonic flowmeters send and receive ultrasonic waves between transducers in both the upstream and downstream directions in the pipe. At no flow conditions, it takes the same time to travel upstream and downstream between the transducers. Under flowing conditions, the upstream wave will travel slower and take more time than the (faster) downstream wave. When the fluid moves faster, the difference between the upstream and downstream times increases. The transmitter processes upstream and downstream times to determine the flow rateAnother method in ultrasonic flow metering, also not suited for very low flowrates, is the use of the Doppler shift that results from the reflection of an ultrasonic beam off sonically reflective materials, such as solid particles or entrained air bubbles in a flowing fluid, or the turbulence of the fluid itself, if the liquid is clean.