Patent ID: 6871534

Claim:
A flow rate measuring device comprising: a post located in a fluid passage, the fluid passage passing a fluid flow and the post extending across a part of the fluid flow; a measuring duct in the post, the measuring duct including a fluid introduction port having an elongated shape confronting a flow direction of the fluid flow, the elongated shape having a maximum inside dimension in a longitudinal direction and an inside dimension in a transverse direction, perpendicular to the longitudinal direction and smaller than the maximum inside dimension, the longitudinal and transverse directions being perpendicular to the fluid flow; and a flow rate detector located in the measuring duct and comprising a substantially plate-shaped mounting member extending along the fluid flow and bridging the measuring duct, substantially parallel to the longitudinal direction of the elongated shape of the fluid introduction port, and a flow rate detection element on a main surface of the mounting member, wherein the measuring duct has a portion extending from the fluid introduction port to the flow rate detector substantially smoothly narrowing along the longitudinal direction of the elongated shape.