Patent ID: 8650947

Claim:
A device for measuring the flow rate of a fluid, the device comprising: a measure cell having at least one fluid flow inlet and at least one fluid flow outlet and providing a fluid flow path between the inlet and outlet; a selected one of: a heated measure element arranged in the measure cell so as to be exposed to heat transfer effects of fluid flowing through the fluid flow path and a heated reference element arranged in the measure cell so as to have reduced exposure to fluid flowing through the fluid flow path compared to the measure element, wherein the measure and reference elements are each heated with respect to the temperature of the measure cell; or a cooled measure element arranged in the measure cell so as to be exposed to heat transfer effects of fluid flowing through the fluid flow path and a cooled reference element arranged in the measure cell so as to have reduced exposure to fluid flowing through the fluid flow path compared to the measure element, wherein the measure and reference elements are each cooled with respect to the temperature of the measure cell; wherein the measure and reference elements are symmetrically or equivalently arranged within the measure cell for thermal exchange between the measure and reference elements, such that they experience an equivalent heat transfer environment, other than the heat transfer effects due to fluid flowing through the fluid flow path; at least one measurement component connected to at least one of the measure element and the reference element, for measuring at least one parameter that is indicative of the heat transfer effects of fluid flowing through the fluid flow path; and means for deriving a signal indicative of the fluid flow rate from the at least one measured parameter.