A thermal gas flow meter — also called a thermal mass flow meter — measures gas flow by heat transfer. One sensor on the probe is heated, and the moving gas carries heat away from it. The more gas flows past, the more heat it removes, so the meter reads mass flow directly.

The probe is inserted into the pipe and has no moving parts, so it adds almost no pressure drop. It suits compressed air, biogas and other process gas lines where you want to track consumption.