US Patent 7464722 Fluid proportioning valve

A fluid proportioning valve meters flow of pressurized inlet fluid in proportion to a pressure drop between the inlet and outlet of the valve. A pressure acutated, return biased poppet valve is actuated by the fluid above threshold fluid pressure to meter fluid to the outlet against spring force. The poppet is annular and has a circular metering edge that controls flow through circumferential orifices in a valve guide. Smooth stable flow is achieved by shearing action of the metering edge over the orifices. Sliding point contact with the poppet valve by non-ferrous convex buttons to eliminate galling and reduce particle contamination within the valve.