Abstract: In a power plant boiler having oil and coal burning capability, a coal disperser support tube and an oil gun extending through the disperser support tube are slidable in a bearing sleeve extending through a removable access plate in the wall of an elbow of a coal guide. The disperser is arranged to be withdrawn into the coal guide delivery pipe by a first two-position, reversible, linear pneumatic actuator, and the oil gun is arranged to be withdrawn into the disperser support tube by a second similar actuator the body of which is carried with the piston of the first actuator and the piston of which is connected to the oil gun. The piston of the second actuator is withdrawn when the piston of the first actuator is extended to minimize space requirements. The dispenser support, oil gun, actuators, and associated parts are all mounted on the removable access plate, and can be removed as a unit with the access plate.

Abstract: In a valve system for controlling the flow of liquid fuel and steam to a nozzle in a large scale power plant boiler, a pair of valves are operated by rotary pneumatic actuators. Three-position operation is achieved for one of the valves by coupling the valve shafts together through a lost-motion coupling and using an actuator for the other valve which delivers more torque than the actuator which operates the three-position valve. The same actuator and coupling system can be used for straight high pressure mechanical atomization, for mechanical atomization with recirculation, and for steam atomization, with simple substitution of rotary valves.