US Patent 7748268 Thermal flow meter

A thermal mass flow controller or mass flow meter having a novel sensor housing that reduces heat conduction from the housing mounting plate or base to the sensor itself. The housing also greatly minimizes the thermal gradient that can result from the uneven application of heat to the housing base. This reduction is accomplished in part by the use of one or more thermal isolation slots to isolate the upper portion of the housing (which holds the sensor) from the lower portion of the housing. Heat transfer to the sensor housing is also minimized by raising the middle portion of the bottom of the housing so that thermal contact is made between the base and the housing only at the two ends of the housing.