Abstract: Molten metal is delivered from a master furnace to the molten metal holding chamber of a low pressure casting machine by a launder assembly having a unitary, quickly replaceable, valve assembly including a valve which, when closed, prevents flow of the molten metal from the master furnace to the holding vessel. The valve has a plug mounted for rotation in a valve body which may be made from graphite. In a modification, the valve has a port centered in a valve plate and a movable plug which may be made from aluminum titanate. In operation, the valve is opened to permit the molten metal within the master furnace and the holding vessel to seek a substantially uniform level and closed when the low pressure casting process is initiated. While the valve is closed, a pressurizing gas is introduced into the holding vessel above the level of the molten metal therein so that molten metal will rise up a riser tube into the cavity of a mold or other molten metal-receiving member.

Abstract: Molten metal is delivered from a master furnace to the molten metal holding chamber of a low pressure casting machine by a launder assembly having a unitary, quickly replaceable, valve assembly including a valve which, when closed, prevents flow of the molten metal from the master furnace to the holding vessel. The valve has a plug mounted for rotation in a valve body which may be made from graphite. In a modification, the valve has a port centered in a valve plate and a movable plug which may be made from aluminum titanate. In operation, the valve is opened to permit the molten metal within the master furnace and the holding vessel to seek a substantially uniform level and closed when the low pressure casting process is initiated. While the valve is closed, a pressurizing gas is introduced into the holding vessel above the level of the molten metal therein so that molten metal will rise up a riser tube into the cavity of a mold or other molten metal-receiving member.

Abstract: The upper structure of an aluminum melting furnace is constructed with supporting structure for a fossil fuel burner and supporting structure for electrically operated heating elements. The furnace may thus be operated with alternate heating systems, one system using fossil fuel and the other electricity.

Abstract: An electrically energized aluminum melting furnace comprises a vessel for supporting molten aluminum and a roof and upper wall structure cooperating with side walls of the vessel to define a heating chamber above the molten aluminum. A plurality of unshielded resistance heating elements are supported by the roof and upper wall structure above the molten aluminum. The molten aluminum has access through a submerged opening to a charging well to which unmelted aluminum is periodically charged without danger that molten aluminum will splash upon the heating elements. Heat conducted from the heating chamber through the body of molten aluminum residing in the vessel is utilized to melt in the charging well the aluminum charged thereto. The melted aluminum in the charging well is permitted to flow through the heating chamber and through a submerged opening to a hot metal well from which hot metal may be withdrawn by any of numerous techniques.