Patent ID: 7653503

Claim:
A temperature compensating fluid flow sensing system comprising: a first resistance-based sensor element positionable in a fluid flow stream, the first sensor element having a sensor resistance that varies with fluid flow conditions based on heat transfer between the first sensor element and the fluid; a first constant voltage anemometer circuit including the first sensor element, the first constant voltage anemometer circuit being configured to establish and maintain a command voltage across the first sensor element and to provide a CVA output voltage corresponding to the resistance change in the first sensor element due to heat transfer between the first sensor element and the fluid; a controller in communication with the first constant voltage anemometer circuit, the controller being configured to establish the command voltage based on a desired overheat across the sensor and an actual overheat across the first sensor element; and a PDR module in communication with the first constant voltage anemometer circuit and the controller, the PDR module being configured to receive the CVA output voltage and the command voltage from the first constant voltage anemometer circuit, to determine at least one fluid flow parameter and an actual overheat value based at least in part on the CVA output voltage from the first constant voltage anemometer, and to transmit to the controller the actual overheat for use by the controller in updating the command voltage.