Low-pressure isostatic casting process and machine
AssigneeEtude et Developpement en Metallurgie (S.A.R.L.)
InventorPierre L. Merrien
Life of this patent
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Abstract
In this low-pressure casting process a mold is filled from the bottom with a liquid metal or alloy contained in a hermetically sealed furnace. The metal or alloy is forced into the mold through an injection tube by a pressurized fluid. A crucible containing the metal or alloy in the furnace is separated from electrical heating elements and thermally insulative parts by a sealed metal inner jacket supporting the crucible. Fluid is fed from the side of the inner jacket opposite the crucible throughout the casting operation, until the cast part has solidified. The pressure of this fluid is varied according to the pressure above the surface of the metal or alloy in the crucible, so as to maintain a pressure balance at all times between the inside and the outside of the inner jacket.
Claims12
A low-pressure casting process comprising:
- (a) providing a crucible containing metallic substance in a hermetically sealed furnace and a mold for receiving said metallic substance located outside said furnace, said mold communicating with said crucible by means of a conduit having one end positioned within said crucible and another end opening into said mold, said furnace being divided by a sealing metal inner jacket supporting said crucible wherein said sealing metal jacket divides said furnace into two spaces, said crucible located in a first space and said electrical heating elements and thermally insulative parts located in a second space;
- (b) introducing a pressurized first fluid into said first space to force said metallic substance through said conduit and into said mold in a manner so that said fluid is introduced from a side of said jacket opposite said crucible throughout the casting operation until the cast product has solidified;
- (c) varying a pressure of a second fluid in said second space according to pressure of said first fluid above the surface of said metallic substance in said crucible so as to maintain a pressure equilibrium at all times between the inside and the outside of said inner jacket.
A low-pressure casting machine for implementing a low-pressure casting process comprising a sealed outer furnace jacket, a crucible positioned inside said outer jacket for containing a metal substance surrounded by electrical heating elements, refractory and thermally insulated elements wherein said crucible, electrical heating elements, refractory and thermally insulated elements are positioned inside said outer jacket, a lid, a casting nozzle on said lid, and on said lid, a metal inner jacket fixed in a fluid-type manner to a frame of said furnace supporting said crucible and isolating said furnace in a first space in a fluid-tight manner from a second space containing said heating, refractory and insulative elements, means for pressurizing and depressurizing said first space including a first region above the surface of said metal substance in said crucible, means for establishing communication between the second space and a source of pressurized fluid or a vacuum, said means for establishing communication incorporating a valve, and a regulator with a pressure sensor located in said first space and a separate pressure sensor located in said second space connected to said regulator, wherein said regulator is arranged so as to maintain pressure equilibrium between said first space and said second space.
Dependencies are inferred from the claim text.