Variable area inlet guide vanes

Claim 1

For a gas turbine engine of the type that compresses air ingested thereby said engine having a combustor with a substantially closed front end, an aerating fuel nozzle mounted in an opening in said front end of said combustor for feeding fuel into said combustor, a first set of air inlet guide vanes for feeding air into said combustor in a manner to circumscribe the fuel jet spray issuing from said fuel nozzle, a second set of air inlet guide vanes for issuing air also to circumscribe the fuel jet spray surrounding said first set of air inlet guide vanes, self-actuating valve means solely responsive to the differential pressure upstream of said combustor and downstream of said combustor relative to the flow of air flowing into and out of said combustor for automatically activating said valve means to admit air to said second set of inlet guide vanes upon reaching a predetermined value of said differential pressure, an annular member having a depending lip attached to said front end of said combustor, said self-actuating valve means including a ring-like element having an extended portion subjected to said differential pressure in abutting engagement with said depending lip when said valve is blocking off the flow of air, a plurality of resilient members engaging said extended portion for imparting a force for urging said extended portion in sealing engagement with said depending lip, said pressure differential acting across said extended portion overcoming the force urged by said resilient members to deploy said extended portion away from said depending lip whereby air is admitted to said second inlet guide vanes, whereby said valve means normally blocks off the flow of air to said second inlet guide vanes, said ring-like element partitions said first set of air inlet guide vanes and said second set of air inlet guide vanes.