Air flow transducer

Claim 1

An air flow transducer for measuring the rate of air flow into the intake manifold of an internal combustion engine having a propensity to backfire on occasion, said transducer comprising a flow tube forming a passageway, means for mounting said flow tube to pass the air flowing to said intake manifold through said passageway, a rotor having a shaft with a hub mounted thereon for rotation therewith and a plurality of vanes extending outwardly from said hub, means for mounting said shaft for rotation of said rotor within said passageway, and signal means for providing an electrical signal systematically related to the rate of rotation of said rotor, said vanes being equally spaced around the periphery of said hub and shaped to intercept air flowing through said passageway for movement by said air, said vanes being formed of low density plastic, each of said vanes having a thickened root at which it joins said hub, and each of said vanes having a trailing edge that slopes from said hub in the upstream direction at a substantial angle to the plane normal to said shaft to provide a reaction surface to any backfire pressure wave that forces said trailing edge in the direction of said hub in counteraction to forces created by said backfire pressure wave directed to tearing said vane from said hub.