PILOT-OPERATED VALVE

摘要

Provided is a valve having a movable valve member with an orifice, a plunger movable to block/allow flow through the orifice, and a resilient biasing member for resiliently biasing the valve member away from the valve seat. When the plunger is moved to a position allowing flow, fluid flows through the orifice creating a pressure differential in the valve that in combination with the resilient biasing member moves the valve member to a position allowing flow through a main passageway of the valve. During a low or no flow condition, the valve member is held in the position allowing flow to prevent a drop in performance of a system utilizing the valve that would result if the valve member moved to a blocking position.

主权项

1. A valve including:
a valve body having an inlet port, an outlet port in selective fluid communication with the inlet port by a main passageway through the valve, and a valve seat surrounding the main passageway; a valve member mounted in the valve body for movement between first and second positions respectively blocking and permitting flow through the valve seat, the valve member having a piston portion that separates a control chamber upstream of the valve seat from a point downstream of the valve seat and a pilot orifice through the piston portion for bleeding off pressure from the control chamber to the point downstream of the valve seat; a plunger movable between a first position blocking flow through the pilot orifice and a second position allowing flow through the pilot orifice; and a resilient biasing member connecting the valve member to the plunger, wherein the resilient biasing member holds the valve member in the second position away from the valve seat when the plunger is in the second position.