US Patent 10180106 Solenoids for gas turbine engine bleed valves

A solenoid for a bleed valve includes a solenoid body with an actuation fluid passage, a bleed valve passage, and a drive fluid chamber. A main armature is disposed within the solenoid body and is movable between open and closed positions, the actuation fluid passage being in fluid communication with the control outlet in the open position, the actuation fluid passage being fluidly isolated from the bleed valve passage in the second position. A pilot armature is disposed within the solenoid body, is movable relative to the main armature, and is operably coupled to the main armature by the drive fluid chamber to move the main armature between the open and closed positions by controlling issue of a drive fluid into and out of the drive fluid chamber.