Pintle valve having an internal flow modifier with self-aligning head

摘要

A flow modifier for insertion into the chamber of a large pintle valve to change the apparent flow range of the valve to that of a smaller valve. The flow modifier includes a perforated cup-shaped restrictor disposed within the valve on the valve pintle and sealingly surrounding the valve seat such that all flow through the valve must pass through the passageways in the restrictor. The restrictor is held in place by a compression spring surrounding the pintle. The total open area of the passageways may be varied by varying their number and/or size and is preferably substantially less than the open area of the valve seat. The restrictor thus acts as a flow choke or fixed throttle to reduce the flow range of the valve. Different restrictors may be provided as required to size a single large valve having a large inherent flow range to a plurality of applications requiring valves having smaller flow ranges. A further embodiment includes a valve head resiliently and articulably mounted on the internal end of the valve pintle. The head is free to move axially and/or radially and/or rotationally with respect to the pintle as directed by the mating surface of the valve seat to effect a seal therewith.