Qualley Ray W, Thompson Robert L: Dual fuel burner apparatus. Modine Manufacturing Company, Hofgren Wegner Allen Stellman & McCord, August 13, 1974: US3829279 (55 worldwide citation)

A dual fuel burner apparatus for burning two or more different types of fuel some of which require greater amounts of primary air entrapped with the fuel than others and comprising a first nozzle for a first fuel having an orifice directed into and located adjacent to the entrance end of a mixer cha ...