A Thermal Mass Flow Meter is an instrument used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas.
Fox Flow Meters use a Constant Temperature Differential (?T) technology. The sensor has two elements. The Reference RTD measures the gas temperature. The electronics heats the Heated Element above the gas temperature. It is the job of the electronics to maintain a constant ?T between the gas temperature and the Heated Element. As mass flow increases, the increased numbers of gas molecules remove more heat from the Heated Element.
The electronics senses this temperature reduction and adds additional power to the heated element in order to maintain a constant ?T. The amount of power delivered to the Heated Element is proportional to the mass flow rate. The microprocessor then linearizes this signal to deliver a linear output.