VARIABLE ORIFICE FLOW SENSOR

摘要

The invention relates to a variable orifice flow sensor with a flow conduit member defining a flow orifice and fluidly connecting first and second fluid flow ports, a magnetizable metal flapper mounted in the conduit member by a hinge portion so that a zero-flow gap is defined between the flapper and the conduit member when there is no fluid flow through the orifice and so that the flapper angularly deflects out of the plane of the orifice in response to fluid flow through the conduit member to vary the effective fluid flow cross-sectional area of the orifice in proportion to the flow rate of fluid through the conduit member, and a pressure sensing tap on either side of the flapper; and a magnetic element configured to generate a magnetic field that forces the flapper into a position that tends to minimize the zero flow gap.