Apparatus for the countergravity casting of metals

A countergravity casting apparatus comprising:

• reservoir means (14) having a casting chamber (46) therein for containing a supply of molten metal, said casting chamber (46), provided with a cover (40) for defining an enclosed air space over the metal in said chamber (46),
• said reservoir means (14) including inert gas purging means (64) for delivering inert gas directly into said air space (62) and purging it of any external atmospheric gases which would otherwise react with and contaminate the metal in said chamber (46);
• a casting mold (12) supported above said reservoir means (14), said mold (12) having an internal mold cavity (24) formed therein and a plurality of inlets (28) extending from a bottom side (26) of said mold (12) into said cavity (24) for admitting molten metal into said cavity (24);
• a secondary distribution vessel (78) between said reservoir means (14) and said mold (12), said vessel (78) having a distribution chamber (82) therein with an inlet (86) into said chamber (82) through a bottom side of said vessel (78) and a plurality of outlets (90) formed in a top side (88) of said vessel (78), said mold (12) being supported on said top side (88) of said vessel (78) with said plurality of inlets (28) of said mold (12) in aligned registry with said plurality of outlets (90) of said vessel (78);
• electromagnetic pump means (66) associated with said casting chamber (46) and fluidly coupled with said distribution vessel (78) through an uphill feed tube (76), said pump means (66) being responsive to an input voltage applied thereto for pumping the metal with pressure against gravity from said casting chamber (46) into said distribution vessel (78) through said feed tube (76) and thence into said mold cavity (24) through said plurality of bottom inlets (28) of said mold (12) to thereby fill said mold cavity (24) with the molten metal;
• feedback pressure control means (98) for continuously directly measuring the actual pressure of the pumped metal during the casting cycle and controlling said input voltage to said pump means (66) for conforming the actual metal pressure with an ideal reference metal pressure versus casting cycle time mold filling schedule of said control means (98).