Armstrong Ultrasonic Flowmeter And BTU Meter

The Armstrong Ultrasonic Flowmeter (AUF) is designed to be installed at a fixed location for long-term flow measurement on a closed pipe, carrying pure liquids or liquids with some suspended particles. The AUF will be equipped with clamp-on transducers to meet various application challenges.


An ultrasonic flowmeter is a clamp on style flowmeter that uses transducers to measure the transmission time of ultrasonic signal both with and against flow (Figures 1 and 2). The time differential is proportional to velocity of liquid.

BTU Measurement

With a matched pair of 100 OHM 3 wire platinum RTD temperature sensor probes and a thermal energy module, the AUF-B can measure the thermal energy (BTU) using the temperature of the supply and return lines of a heating or cooling circuit. The AUF provides versatile input and output interfaces, such as digital and relay outputs, batch control, alarm and flow/energy totalizing, 4-20mA output, RS485/MODBUS and optional BACnet (IP or MSTP) output, which can be easily used by a host computer, BMS, PLC or a flow controller for process monitoring and control.


The advantages of Armstrong’s Ultrasonic Flowmeter are no moving parts/maintenance, NIST traceable factory calibration, multi frequency system, thermal energy measurement, no shutdowns/pipework for installation, and optional communication protocols: BACnet, GPRS, RF wireless, RS485/MODBUS.