Patent ID: 7644726

Claim:
A fluid flow shutoff valve comprising: a housing having an inlet section with an inlet, an outlet section with an outlet, and a passage between the inlet and the outlet, the outlet section including a valve seat, the valve seat and an internal surface of the outlet section defining boundaries of an annular space; a poppet guide and metering slot insert having at least one metering slot disposed within the inlet section, the at least one metering slot forming a perforation passing completely through a side wall of the poppet guide and metering slot insert, a valve element slidably mounted in the passage between a first position and a second position with at least one intermediate position therebetween and including a sealing surface at a downstream end, the sealing surface being configured to engage the valve seat, a wall of the valve element slidably engaging the poppet guide and metering slot insert; and a spring in compression between the housing and the valve element biasing the valve element toward the inlet and away from the valve seat, a downstream portion of the spring being disposed within the annular space; wherein the valve element is configured to control flow between the inlet and the outlet through the at least one metering slot, the first position being with the sealing surface displaced from the valve seat and communication through the at least one metering slot closed, the second position being with the sealing surface engaging the valve seat to completely seal flow through the valve seat and the at least one metering slot open to the inlet only, and the at least one intermediate position being with the sealing surface displaced from the valve seat and the at least one metering slot open to the inlet and the outlet.