Armstrong Ultrasonic Portable Flowmeter and BTU Meter

The Armstrong Ultrasonic Portable Flowmeter (AUP) hand held unit is the most compact yet powerful flow/BTU meter on the market. The utilization of our proprietary technologies, such as ultrasonic signal processing, signal quality tracking, and self-adaptation as well as high density electronic design, allows the device to measure liquid flow, temperature and thermal energy from outside of a pipe reliably and accurately.


Armstrong ultrasonic portable flow and energy meters are based on the transit-time measurement principle, where the system utilizes a pair of sensors (Figures 1 and 2) that function as both ultrasonic transmitter and receiver. The sensors are installed on the pipe wall, either clamped on the outside of the pipe or inserted into the pipe at a specific distance from each other. The flowmeter operates by alternately transmitting and receiving a coded burst of sound energy between the two sensors and measuring the transit time it takes for sound to travel between the two sensors. The difference in the transit time is directly related to the velocity of the liquid in the pipe. The flowrate is then calculated based on the transit-time difference, the geometry of the pipe and the fluid dynamics formula.

Convenience on the Go

The advantages of Armstrong’s Ultrasonic Portable Flowmeter are thermal energy measurement, bi-directional flow, non-intrusive installation, and data logging all in a convenient portable package.