Double-acting seal for metering valve

Claim 1

In a fluid control device: a housing having an inlet, an outlet, and a bore communicating the inlet with the outlet; a valve seat area on said housing in said bore; first and second relatively movable coaxial valve members reciprocable in said bore dividing the latter into an inlet chamber and an outlet chamber; first resilient means yieldably biasing said first valve member into engagement with said valve seat area; and second resilient means carried by said first valve member yieldably biasing said second valve member from said first valve member whereby fluid communication between the inlet and outlet chambers is permitted until a predetermined level of fluid pressure in said inlet chamber overcomes the bias of said second resilient means to drive said second valve member into sealing engagement with said first valve member whereupon fluid communication between the chambers is terminated until a second predetermined pressure is achieved sufficient to overcome the bias of said first resilient means to drive said first valve member from said valve seat area to permit fluid communication between the chambers; said first valve member having an annular section telescopingly receiving said second valve member and a second projecting radially outwardly from said annular section; said outwardly projecting section being adapted to engage said valve seat area; said annular section having a diameter substantially larger than said second valve member to define an annular chamber between said annular section and said second valve member; said second resilient means being a coiled spring disposed in said annular chamber; said second valve member including a valve stem having larger and smaller diameter portions presenting a shoulder therebetween; said annular section having a radially inwardly projecting lip; said spring operatively interconnecting said lip and said shoulder.