Abstract: An fluid flow rate measuring device preferably includes an airfoil, a differential pressure sensor and a programmable electronic controller. The airfoil includes a leading edge, a first pressure chamber, a second pressure chamber, and a trailing edge. At least one first hole is formed through the first pressure chamber. At least one second hole is formed through the second pressure chamber adjacent the trailing edge. The at least one first hole communicates with the first pressure chamber. The at least one second hole communicates with the second pressure chamber. The first and second pressure chambers are connected to first and second input ports of the differential pressure sensor. The differential pressure sensor outputs a voltage to the programmable electronic controller. The programmable electronic controller takes a square root of the differential pressure and multiplies it by a K factor to produce an fluid flow rate in CFM.

Abstract: A sealed prism assembly including a prism having a cylindrical body region which terminates at one of its ends with an annular flange. Encasing the body region and fitting closely thereabout is a cylindrical cup terminating at a circular end which contacts the flange. A silicone rubber sealant distributed between the prism body region and the cup forms an expandable-contractable air-tight seal therebetween. The prism and cup are encased in a canister in an axially compressed condition.