Patent ID: 7284450

Claim:
An averaging orifice plate fluid flow meter for measuring the volumetric rate of fluid in a conduit, comprising: a constant diameter conduit for carrying fluid from an upstream to a downstream location; a planar flow impedance plate disposed transversely across the interior of the conduit; a set of at least three circular apertures in the planar flow impedance plate eccentrically disposed with respect to the longitudinal axis of the conduit, wherein the set of at least three circular apertures defines all of the circular apertures disposed through the planar flow impedance plate that are eccentrically disposed with respect to a center point of the planar flow impedance plate, wherein each of the set of at least three circular apertures has a center point that is disposed on a single circle having a center point coincident with the center point of the planar flow impedance plate so that the set of at least three circular apertures are disposed symmetrically around the center point of the planar flow impedance plate; a first static pressure sensing element disposed within the conduit upstream of the planar flow impedance plate and proximate thereto; a second static pressure sensing element disposed within the conduit downstream of the planar flow impedance plate and proximate thereto; and a transmitter coupled to the first and second static pressure sensing elements to determine the volumetric rate of fluid in the conduit.