US Patent 7279128 Molten metal pressure pour furnace and metering valve

An apparatus and process are provided for discharging a dose of a molten metal from a pressure pour furnace. A heating chamber of the furnace is used to keep the molten metal at a selected temperature. A sealing port between the heating chamber and a pressure chamber allows selectively filling of the pressure chamber with molten metal from the heating chamber by inserting or removing a sealing means from the sealing port. The sealing means inserted in the sealing port also provides a means for preventing back flow of the molten metal to the heating chamber when the pressure chamber is pressurized. Differential pressure sensing of the pressure of the molten metal in the pressure chamber and the pressure of the pressurizing gas in the pressure chamber can optionally be used to achieve an accurate measured discharge from the pressure chamber as the level of molten metal decreases from repeated discharges of doses from the furnace. The sealing plate in which the sealing port is disposed and the sealing means selectively inserted or removed from the sealing port can be used as a metering valve between two molten metal containing components such as a launder and a pressure chamber of a pressure pour furnace.