Patent ID: 7004193
Filing Date: 2006-02-28
Classification: E01F,F16K,Y10T

Abstract:
1. An air flow control valve arrangement comprising at least a first and a second valve, and a body for housing the first and second valves, the body defining an air outlet, and an annularly-shaped air inlet having a diameter substantially smaller than the air outlet so that the air inlet forms a jet, wherein the first valve includes a first valve closure, movable against a first biasing means from its natural open state to a closed state, and wherein the second valve includes a second valve closure, movable against a second biasing means from its natural closed state to its open state such that the application of air pressure on the control valve assembly below a first lower threshold level or above a second higher threshold level allows a flow of air through the valve arrangement but an application of air pressure on the control valve between said first and second threshold levels allows substantially no air to flow through the valve arrangement, said first valve closure comprising a member having a shaft portion and a broad flat head portion defining an annular sealing face connected to the shaft portion, the first valve closure being located in an axial bore having an annular seat such that in the closed position the head portion of the first valve closure sealably engages with the annular seat, and wherein the second valve closure comprises a generally annular member, the periphery of the generally annular member cooperating with the annular seat of the first valve and which defines a central passageway incorporating the first valve closure, the first valve closure being operative to open and close the passageway.