US Patent 6915705 Flow sensor and flow resistive element

A flow sensor is disclosed that measures a flow of fluid passing through a conduit and a flow resistive element for use in such a flow sensor. The flow sensor includes a housing having a main channel defined therethrough. A flow resistive element is disposed in the housing across the main channel. The flow resistive element includes a rigid body member having a first surface and a second surface. A plurality of unobstructed, wedge-shaped, openings are defined in the body member and extend through the rigid body member. In addition, a plurality of spokes extend from a central portion of the body member to its perimeter so that each spoke separates adjacent wedge-shaped openings from one another.