Fuel nozzle for gas turbine engine

Claim 1

A dual orifice type fuel nozzle having a primary fuel passage normally continuously operative throughout the engine operating envelope and a secondary fuel passage normally operative solely during the high thrust regimes and inoperative during the low thrust regimes of said engine operating envelope, for a combustor of gas turbine engine having a compressor, said fuel nozzle having a generally conically shaped casing with a primary fuel passage centrally disposed therein, secondary fuel passage formed therein concentrically disposed relative to the primary fuel passage, both primary and secondary passages exiting fuel into said combustor through a substantially mutual transverse plane, means for imparting a swirl component to compressor discharge air surrounding the fuel exiting from said primary and secondary passages, means for pressurizing the secondary passage when said primary passage is solely operative with said compressor discharge air whereby said secondary passage maintains a positive pressure for preventing fuel from said primary passage from migrating therein and coking the walls of said secondary passage, first fuel swirl means in said primary passage for imparting a swirl motion to the fuel issuing therefrom, second fuel swirl means in said secondary passage for imparting a swirl motion to the fuel issuing therefrom, said first fuel swirl means, said second fuel swirl means and said means for swirling the air imparting swirling motion in a common direction.