Method for melting a non-ferrous metal charge with liquid fuel

A method for heating and melting a non-ferrous metal charge in a furnace utilizing liquid fuel, atomizing air and combustion air without contaminating the charge with the liquid fuel, comprising the steps of:

• separately supplying liquid fuel, atomizing air and combustion air to a burner assembly mounted adjacent a refractory block formed in the wall of said furnace;
• pre-mixing the liquid fuel and atomizing air within a valve housing means by flowing said atomizing air into and through said liquid fuel before coming into contact with said combustion air, then further pre-mixing said liquid fuel and atomizing air by flowing said mixture through a needle valve means for atomizing the liquid fuel prior to combustion;
• combining the atomized liquid fuel with combustion air adjacent a mixing throat formed between the needle valve means and an inlet portion of the refractory block after said pre-mixing step;
• flowing the mixture of liquid fuel, atomizing air and combustion air from the mixing throat past a first stepped turbulence means into a combustion chamber formed in the refractory block;
• turbulently mixing the mixture of liquid fuel, atomizing air and combustion air to ensure vaporization of the mixture for substantially complete combustion of the mixture within the combustion chamber;
• burning the vaporized mixture in the combustion chamber in order to provide heat for heating and melting the non-ferrous metal charge, while preventing contamination of the non-ferrous metal charge in the furnace with uncombusted fuel;
• and
• discharging the combusted mixture from the combustion chamber past a second stepped turbulence means through an exit venturi arranged within the refractory block, said exit venturi being of a diameter which reduces curvilinearly from an adjacentportion of the combustion chamber outwardly toward the throat of the refractory block;
• whereby the metallurgical quality of the non-ferrous metal charge is maintained.