Patent ID: 8291707

Claim:
A multi-stage check valve for regulating fuel flow in a fuel injector of a gas turbine engine comprising: a) a valve housing defining an internal valve chamber; b) a main valve member within the valve chamber of the valve housing, the main valve member having an internal valve chamber and being configured for movement between a first position and a second position, wherein in the first position thereof, the main valve member blocks fuel below a predetermined main pressure from flowing through a main fuel path, and in the second position thereof, the main valve member is displaced to allow fuel above the predetermined main pressure to flow through the main fuel path; and c) a pilot valve member within the valve chamber of the main valve member, the pilot valve member having a piston portion with an internal pilot flow cavity and being configured for movement relative to the main valve member between a first position and a second position, wherein in the first position thereof, the pilot valve member engages a pilot valve seat to block fuel below a predetermined pilot pressure from flowing through a pilot fuel path, and in the second position thereof, the pilot valve member is displaced to allow fuel above the predetermined pilot pressure to flow through the pilot fuel path, wherein the pilot fuel path includes a metering orifice configured for movement within the internal valve chamber and spaced axially downstream of the pilot valve seat, and wherein in the first position of the pilot valve member, the pilot valve member blocks the pilot fuel path at a position spaced apart from the metering orifice.