Air turbine starter having a force balanced, pressure energized, weighted check valve

摘要

An air turbine starter is provided that includes a check valve assembly for placement between a first environment, at least a portion of which is at a first pressure (P₁), and a second environment, at least a portion of which is at a second pressure (P₂), wherein the difference between the first and second pressures generate a pressure force (F_p). The check valve assembly comprises a valve element disposed between the valve seat and the valve body, the valve element capable of being acted upon by a gravitational force (F_w), a viscous force of the fluid to be communicated between the gearbox assembly and the starter housing (F_v), a buoyancy force of the valve element (F_b), and the pressure force on the valve element (F_p), the valve element further configured to translate axially to a closed position when P₂P₁ and F_wF_v+F_b+F_p.