Two-chamber furnace for countergravity casting

• US 5,948,352 A
• Filed: 10/31/1997
• Issued: 09/07/1999
• Est. Priority Date: 12/05/1996
• Status: Expired due to Term

• Current Assignee: Deltamation Corporation, GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Original Assignee: Deltamation Corporation, General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Tooley, Gordon Alwin, Vender Jagt, A. Dean
• Primary Examiner(s): KASTLER, SCOTT R
• Application Number:
  US08/961,835
• Time in Patent Office: 676 Days
• Field of Search: 266/239, 266/200, 266/236, 222/595, 222/593, 222/602
• US Class Current: 266/239
• CPC Class Codes: B22D 18/04 Low pressure casting, i.e. making use of pressures up to a few bars to fill the mould
• CPC Class Codes: B22D 18/06 Vacuum casting, i.e. making use of vacuum to fill the mould
• CPC Class Codes: B22D 41/015 with external heating, i.e. the heat source not being a part of the ladle
• CPC Class Codes: F27B 3/045 Multiple chambers, e.g. one of which is used for charging
• CPC Class Codes: F27D 3/14 Charging or discharging liquid or molten material

Abstract

A two-chamber furnace for the low pressure countergravity casting of metal wherein the first chamber is a molten metal supply chamber connected by a submerged orifice closable by a stopper rod valve to a sealed second chamber that is pressurizable to fill a superjacent mold. The stopper rod valve is readily replaceable from the top of the furnace without having to empty the melt from the furnace.

Claims

1. A furnace for holding molten metal and dispensing said metal to a mold, said furnace comprising a first chamber for holding a quantity of said metal;

a gas pressurizable second chamber adjacent said first chamber for dispensing said metal to said mold under super ambient pressure conditions;

a partition interjacent said first and second chambers for isolating said chambers one from the other;

an opening in said partition communicating said first and second chambers, said opening being located near the bottom of said second chamber for admitting said metal into said second chamber beneath the level of molten metal in said second chamber;

at least one immersion heater adjacent said opening in said first chamber;

at least one immersion heater adjacent said opening in said second chamber;

a stopper-rod valve operatively associated with said opening to permit metal to flow from said first chamber into said second chamber via said opening when said valve is open and prevent such flow when said valve is closed;

a gas inlet to said second chamber for admitting sufficient pressurized gas into said second chamber to displace molten metal therein externally of said second chamber; and

an outlet form said second chamber for discharging molten metal displaced by said gas from said second chamber into said mold.

2. A furnace for holding molten metal and dispensing said metal to a mold, said furnace comprising a first chamber for holding a quantity of said metal;

a gas pressurizable second chamber adjacent said first chamber for dispensing said metal to said mold under super ambient pressure conditions;

a partition interjacent said first and second chambers for isolating said chambers one from the other;

an opening in said partition communicating said first and second chambers, said opening being located near the bottom of said second chamber for admitting said metal into said second chamber beneath the level of molten metal in said second chamber;

at least one immersion heater adjacent said opening in said first chamber;

at least one immersion heater adjacent said opening in said second chamber;

a gas inlet to said second chamber for admitting sufficient pressurized gas into said second chamber to displace molten metal therein externally of said second chamber;

an outlet form said second chamber for discharging molten metal displaced by said gas from said second chamber into said mold; and

a readily replaceable stopper-rod valve assembly comprising;

(a) a stopper moveable between an open position for allowing metal to flow through said opening and a closed position to prevent metal from flowing through said opening, and

(b) a sheath surrounding said stopper, said sheath having (1) a valve seat mateable with said stopper on one end of said sheath adjacent said opening and defining an orifice in registry with said opening, and (2) at least one aperture through a wall of said sheath for admitting metal into said sheath from the first chamber and thence through said orifice into said second chamber when said stopper is in said open position.

3. A furnace for holding molten metal and dispensing said metal to a mold, said furnace comprising a first chamber for holding a quantity of said metal;

a gas pressurizable second chamber adjacent said first chamber, said second chamber being adapted to receive a pressurizing gas for dispensing said metal to said mold under super ambient pressure conditions;

a partition interjacent said first and second chambers for isolating said chambers one from the other, said partition comprising a first refractory material permeable by said pressurizing gas and a barrier layer of a second refractory material which is impermeable by said gas to prevent said gas from bleeding into said first chamber when said second chamber is pressurized;

an opening in said partition communicating said first and second chambers, said opening being located near the bottom of said second chamber for admitting said metal into said second chamber beneath the level of molten metal in said second chamber;

at least one immersion heater adjacent said opening in said first chamber;

at least one immersion heater adjacent said opening in said second chamber;

a stopper-rod valve operatively associated with said opening to permit metal to flow from said first chamber into said second chamber via said opening when said valve is open and prevent such flow when said valve is closed;

a gas inlet to said second chamber for admitting gas into said second chamber to displace molten metal therein externally of said second chamber; and

an outlet form said second chamber for discharging molten metal displaced by said gas from said second chamber into said mold.

4. A furnace according to claim 3 wherein said barrier layer is sandwiched between opposing first and second portions of said partition.

5. A furnace according to claim 3 wherein said barrier comprises mica.