Patent ID: 7828009

Claim:
A flow control device for controlling a fluid flow between an inlet port and an outlet port, comprising: a body having an upper annular portion and an axial bore in fluid communication with the inlet port; a bonnet removably mounted to the body and having a top portion, an axial bore and an axially elongated sleeve extending downwardly from the top portion and having a valve seat, wherein the bonnet axial bore and the body upper annular portion form a cavity within the flow control device with at least a portion of the cavity being in fluid communication with the outlet port; a piston axially disposed within the body axial bore and in a fluid sealing relationship with a wall defining the body axial bore, the piston having an axial bore having an upper portion receiving the sleeve, and apertures placing the piston axial bore in fluid communication with a bottom surface of the piston, the piston being axially movable along the sleeve between a closed position with a shoulder of the piston axial bore engaging the valve seat and an open position with the shoulder disengaged from the valve seat, wherein the outlet port is in fluid communication with the piston bottom surface in both piston positions; a wheel operatively coupled to the top part of the sleeve such that the wheel moves axially along the sleeve when the wheel is rotated; and a spring disposed between the piston and the wheel and biasing the piston toward the open position, wherein the pressure on the bottom of the piston causes the piston to move to the closed position when the outlet port pressure is at least a predetermined maximum outlet pressure, and wherein the predetermined maximum outlet pressure is increased by rotating the wheel in one direction and is decreased by rotating the wheel in the opposite direction, and wherein the bonnet further includes a vent port having a bore extending inwardly from the vent port and intersecting the inner surface of the bonnet proximate the wheel such that the wheel is accessible from the exterior of the flow control device when the bonnet is attached to the body, and engageable to rotate the wheel in either direction, and wherein the wheel comprises a plurality of teeth spaced about an outer circumference of the wheel, and wherein the vent port bore is configured to receive an adjustment tool having a gear with teeth configured to mesh with the teeth of the wheel such that rotation of the adjustment tool causes a corresponding rotation of the wheel, the vent port bore also including an alignment structure that engages a corresponding alignment structure of the adjustment tool when the adjustment tool is inserted into the vent port bore to prevent lateral movement of the adjustment tool within the vent port bore.