Thermal meters measure gas mass flow directly without the need for additional need pressure, temperature and/or density monitoring. They operate either by introducing a known amount of heat into the flowing stream and measuring an associated temperature change, or by maintaining a probe at a constant temperature and measuring the energy required to do so. Thermal mass flowmeters include two temperature sensors and an electric heater between them. The heater can protrude into the fluid stream or may be external to the pipe. By eliminating temperature changes in the process, any heat transfer within the flow stream is directly proportional to its mass flow. For a more complete description of thermal mass flow technologies please go to; http://www.smartmeasurement.com/flow-meters/thermal/measuring-principle
Thermal meters have no moving parts, wide turn-downs (up to 1000:1), a range from 0.02 meters per second (4 feet per minute) to over 200 mps (40,000 fpm), and very low pressure drop. SmartmeasurementTM, s ATMF series of thermal mass flowmeters can be used with pipe diameters ranging from 8mm (¼”) to up to several meters using our multi-sensor configurations. Process connections can be flanged, threaded, or hot-tapped ball valve. SmartmeasurementTM’ s ATMF Series Thermal Mass Flowmeters feature available integral style or remote mount electronics, an easy-to-read OLED display, and a unique calibration self-check technique that allows for field verification of the factory calibration. Please see the Thermal Product Matrix below to select the best configuration for your specific application.