at least one of the fluids being submitted to a swirling motion

Full Title

Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid > Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone (F23D14/38 takes precedence) > with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other > at least one of the fluids being submitted to a swirling motion