Fuel economiser for combustion devices

An economiser for combustion devices, consisting of a preferably steel tube (1) around which at least two coils (B1,B2) set side by side are wound, said coils being traversed by electric current and being capable of inducing an electromagnetic field inside the tube. The coils are enclosed in a preferably metal casing (2) and then possibly resin-potted. The device is preferably designed for improving combustion in engines, boilers, and burners in general.