Thermal dispersion flow meters: how do they work? In many industrial sectors, various types of gases with different characteristics are used every day, which are transported and distributed through pipes. Various measuring principles are available to measure the flow rate: among them the principle based on thermal dispersion. A fluid, in its passage, removes heat from a heated body: this principle can be traced back to the Canadian physicist Louis Vessot King, who in 1914 mathematically described the transfer of heat in moving fluids. Also called thermal mass flow meters? Each meter contains two temperature sensors (also called thermometric resistors): one measures the real temperature of the fluid, which acts as a reference value. The other sensor is electrically heated to maintain a constant temperature difference compared to the first sensor. When the fluid flows into the measuring tube, the heated temperature sensor cools as it passes: each gas molecule, in fact, ...