Abstract: A method and an apparatus for the combustion of high viscosity low grade liquid fuel (e.g., residual oil), in which the fuel is directed through an ejector into an impact chamber in which it impinges upon a baffle with the rebounding fuel particles being further pulverized by jets of air introduced into this chamber with an inclination to the axis of the burner. The resulting fuel-air mixture passes around the impingement baffle with a laminar flow of air passing axially along the wall of this chamber and preventing precipitation of fuel droplets thereon. Upon emergence from the chamber the fuel-air mixture encounters a flow of air passing along the exterior of the impact chamber and intercepted by a plurality of inwardly extending steps which furtherpromote pulverization and mixing.