Proportioning valve for volumetric proportioning of flow

Claim 1

A proportioning valve for volumetric proportioning of flow in an influent fluid line between two effluent fluid lines, comprising, in combination, a housing; a valve chamber; an influent flow passage and two effluent flow passages in the housing in fluid flow connection via the valve chamber; a first valve element interposed across the line of flow between influent and effluent flow passages in a manner to sense influent flow and apportion influent flow between the two effluent flow passages, and mounted in the valve chamber for movement between limiting positions and a multiplicity of intermediate pressure-balanced positions therebetween; the first valve element having a first pressure surface exposed to upstream fluid pressure in the influent flow passage tending to move the valve element in one direction; a second pressure surface exposed to downstream fluid pressure in the valve chamber, tending to move the valve element in the opposite direction; and a third pressure surface exposed to downstream fluid pressure in one effluent flow passage tending to move the element in said opposite direction; the first valve element assuming a position with respect to the limiting positions responsive to influent volumetric flow, and in proportion to such flow and a balancing differential pressure-related force acting on the second and third pressure surfaces; the first valve element defining with side walls of the valve chamber a first variable opening for fluid flow into the chamber from the influent flow passage, the open area of said first opening available for flow being related to the valve position, the first valve element also defining with a wall of said one effluent line passage a second variable opening for fluid flow into the said passage from said chamber, the open area of said second opening available for flow being related to the valve position; the first valve element defining the opening size in proportion to volumetric flow in the influent line into the valve chamber; a second valve element movable independently of and cooperating with the first valve element in defining the size of the second variable opening; the second valve element having a first pressure surface exposed to upstream fluid pressure in the influent flow passage tending to move the valve element in one direction, and a second pressure surface exposed to downstream fluid pressure in the said one effluent line passage tending to move the valve in the opposite direction; bias means urging the second valve element in one direction, and resisting movement of the second valve element in the opposite direction, but permitting movement in that direction at pressures exceeding a predetermined minimum, in a manner such that its resistance to that movement increases as the valve element moves in that direction; the second valve element being movable against the bias means in response to a sufficient differential pressure between the influent passage and the said one effluent flow passage, to define the variable opening size in response to said differential pressure, the first and second valve elements in combination controlling flow in said one effluent flow passage at a desired volume and pressure in relation to pressure and flow in the influent flow passage.