A portable thermal oven includes a metal frame and a plurality of terracotta panels disposed inside of the frame and defining an enclosed chamber having a front panel, a rear panel, two opposite side panels, a top panel and a bottom panel. The furnace also includes a terracotta door hingedly disposed in the front panel and including a handle on one side thereof for opening and closing the door. A plurality of gas manifolds and a plurality of gas burners are disposed on each of the two opposite sides of the chamber and a ventilation hatch is disposed in the top panel for exhausting fumes and excess heat. A first and a second gas cylinder and pipes for connecting the gas cylinders to the manifolds for supplying gas and/or air to the manifolds are also provided.
1. A portable thermal oven for melting gold and other precious metals, said oven comprising:
a metal frame, means for supporting said frame above the level of a floor and a plurality of insulating terracotta plates disposed in said frame and defining an enclosed chamber having a front panel, a rear panel, two opposite side panels, a top panel, a bottom panel and a lower portion;
a terracotta door having four sides hingedly disposed in said front panel along one side thereof and including a handle on one side thereof for opening and closing said door;
a plurality of gas manifolds and a plurality of gas burners disposed on each of said opposite sides of said chamber and a ventilation hatch in said top panel for exhausting excess heat and fumes from said furnace;
a first gas cylinder containing a supply of flammable gas and a pipe connecting said first gas cylinder to said manifolds;
a supply of air or oxygen and means for feeding said air or oxygen into said furnace;
control means for regulating the flow of gas and the amount of air and/or oxygen from said gas cylinder and said supply of air and oxygen to said manifolds for ignition in said burners;
a support member for receiving a mass of gold or precious metal for melting disposed in said lower portion of said chamber and including a plurality of passageways extending therethrough; and
a cone shaped terracotta lined receptacle disposed in said bottom of said chamber and extending through said bottom panel with a larger portion thereof adapted to receive molten metal therein and said bottom portion of said cone-shaped receptacle adapted to direct molten metal into a mold.
2. A portable thermal oven for melting gold and other precious metals according to claim 1 in which said cone shaped receptacle includes an opening and tiltable closure for closing a bottom portion of said receptacle to pour molten metal into a mold or into a casting plate.
3. A portable thermal oven for melting gold and other precious metals according to claim 2 in which said furnace includes a second gas cylinder containing oxygen or other gas and a pipe for connecting said second cylinder to said manifold.
4. A portable thermal oven for melting gold and other precious metals according to claim 3 in which said tiltable closure for opening said cone-shaped receptacle includes a relatively long rod for opening said receptacle from a safe distance removed from molten metal.
5. A portable thermal oven for melting gold and other precious metals according to claim 4 in which said means for supporting said frame above the level of a floor includes four legs having a length at least as long as the height of said chamber and wherein said legs are attached at the corners at the bottom of the frame of said furnace.
6. A portable thermal oven for melting gold and other precious metals according to claim 5 which includes four vertically stacked manifolds on each of said two opposite sides and wherein each of said manifolds include three horizontally aligned gas inlets and a burner at the end of each gas inlet for directing flammable gas into said chamber.
7. A portable thermal oven for melting gold and other precious metals, said oven consisting of:
a metal frame, four legs supporting said frame above the level of a floor and a plurality of terracotta panels disposed in said frame and defining an enclosed chamber having a front panel, a rear panel, two opposite side panels connecting said front and rear panels, a top panel and a bottom panel;
a rectangular terracotta door having four sides hingedly disposed in said front panel and including a handle on one side thereof for opening and closing said door and a glass panel within said door for viewing the interior of said oven;
four vertically spaced gas manifolds disposed on each of said two opposite side panels of said chamber, three gas burners disposed in each of said manifolds and a ventilating shaft disposed in said top panel for exhausting excess heat and fumes from said furnace;
a first gas cylinder including a supply of natural gas and a pipe connecting said gas cylinder to each of said manifolds, a second gas cylinder for supplying air or oxygen or other gas to said chamber and a pipe connecting said second gas cylinder to each of said manifolds;
control means for regulating the flow of flammable gas from said gas cylinder to said manifold and for separately controlling the supply of air, oxygen or other gas from said second cylinder to said manifold for controlling the heat in said oven;
a support plate disposed in a lower portion of said chamber for receiving a mass of gold or precious metal thereon for melting in said oven and said support plate including a plurality of holes extending therethrough;
a cone-shaped terracotta lined receptacle disposed below said support plate and extending through said bottom panel with a larger portion thereof adapted to receive molten metal therein and a closeable opening in a lower portion of said cone-shaped receptacle to deliver molten metal to a mold or casting plate and wherein said closeable opening means includes a relatively long rod for releasing molten metal from said receptacle; and
said furnace including two handles attached to an upper portion of said frame for moving said furnace from one location to another.