varmamassaflæðimælar

Varmamassaflæðimælar are instruments used to measure the mass flow rate of fluids, particularly gases. Unlike volumetric flow meters, which measure the volume of fluid passing a point, varmamassaflæðimælar directly determine the mass of the fluid. This is advantageous because the density of fluids can change significantly with temperature and pressure, making volumetric measurements less accurate for mass flow calculations unless these parameters are also precisely known and compensated for.

The principle of operation for many varmamassaflæðimælar is based on heat transfer. A common design involves introducing a known amount of heat into the fluid stream and then measuring the temperature change or the amount of energy required to maintain a specific temperature difference. By measuring the temperature upstream and downstream of a heated element, or by measuring the power needed to keep a sensor at a constant temperature above the fluid, the mass flow rate can be calculated. This is because the amount of heat absorbed by the fluid is directly proportional to its mass flow rate, assuming constant specific heat.

Varmamassaflæðimælar are widely used in various industries, including HVAC systems, industrial process control, natural gas metering, and research applications. Their ability to provide accurate mass flow measurements independent of pressure and temperature variations makes them a preferred choice in many demanding scenarios. They are known for their robustness and ability to handle a wide range of flow rates. Different types exist, including thermal bypass and thermal insertion meters, each suited for specific applications and fluid conditions.