Heat treatment of metal castings and integrated sand reclamation

A method for heat treating a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the method comprising steps of:

• introducing the casting, with at least a portion of the sand core therein, into a furnace system,
• wherein the furnace system defines
• a heat treating region, and
• a reclaiming region disposed below the heat treating region and in heat and gaseous communication with the heat treating region,
• wherein the furnace system includes a support assembly for supporting the casting within the heat treating region, and
• wherein the introducing step includes a step of placing the casting upon the support assembly;
• heat treating the casting while the casting is disposed within the heat treating region;
• dislodging portions of the sand core from the casting while the casting is disposed within the heat treating region, wherein the dislodging step includes a step of combusting binder material of the portion of the sand core;
• causing the dislodged portions of the sand core to fall from the casting and the support assembly into the reclaiming region;
• reclaiming, at least partially and within the reclaiming region, sand from the fallen portions of the sand core, wherein the reclaiming step includes steps of
• further combusting binder material of the fallen portions of the sand core, and
• agitating the fallen portions of sand core in a manner that facilitates the step of further combusting;
• and
• conveying the reclaimed sand away from the furnace system,
• thereby accomplishing heat treatment, core removal, and at least partial sand reclamation in an integrated process associated with a single furnace system.

A method for heat treating a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the method comprising steps of:

• providing an oxygenated atmosphere;
• heating the oxygenated atmosphere to a temperature in excess of the combustion temperature of the binder material;
• introducing the casting, with at least a portion of the sand core therein, into a furnace,
• wherein the furnace includes a support assembly for supporting the casting within the furnace,
• wherein the introducing step includes a step of placing the casting upon the support assembly,
• wherein the casting is exposed within the furnace to the oxygenated and heated atmosphere to permit binder material to combust, and
• wherein portions of the sand core are loosened from and fall from the cavity of the casting and the support assembly while the casting is within the furnace;
• collecting, distant from the casting and the support assembly, the portions of the sand core which fall from the support assembly prior to the binder material being combusted therefrom;
• maintaining the collected portions of the sand core within the oxygenated atmosphere in a manner that permits binder material to be combusted therefrom such that sand is at least partially reclaimed from the collected portions of the sand core;
• and
• conveying the at least partially reclaimed sand away from the furnace.

A method for heat treating a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the method comprising steps of:

• introducing the casting, with at least a portion of the sand core therein, into a furnace;
• heating the furnace to a temperature in excess of the combustion temperature of the binder material;
• containing the casting, with the at least a portion of the sand core therein, within the heated furnace;
• combusting binder material of at least a portion of the sand core disposed within the casting, whereby portions of the sand core are loosened and fall from the cavity of the casting while the casting is within the furnace;
• collecting the portions of the sand core which fall from the casting;
• fluidizing the collected portions of the sand core within a flow of heated gas such that sand is at least partially reclaimed from the collected portions of the sand core,
• wherein the flow of heated gas is directed into the furnace, and
• wherein the flow of heated gas contributes to the heating of the furnace;
• and
• conveying the at least partially reclaimed sand away from the furnace.

A method for heat treating a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the method comprising steps of:

• introducing a casting with at least some sand core therein into a furnace,
• wherein the furnace includes a support assembly for supporting the casting within the furnace, and
• wherein the introducing step includes a step of placing the casting upon the support assembly;
• heating the furnace to a temperature sufficient to heat treat the casting and sufficient to combust the binder material of the sand core;
• burning binder material of the sand core within the furnace to release sand core portions from the casting, wherein the released sand core portions fall from the cavity of the casting and the support assembly while the casting is within the furnace;
• reclaiming, at a reclaiming region distant from the casting and the support assembly, at least some sand from portions of the fallen sand core portions,
• which reclaiming is accomplished through additional burning of binder material of portions of the fallen sand core portions, and
• wherein the reclaiming region and the furnace are proximately located such that heat passes between the reclaiming region and the furnace;
• and
• thereafter conveying sand and any attached binder material away from the furnace.

A method for heat treating a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the method comprising steps of:

• introducing the casting, with at least a portion of the sand core therein, into a furnace;
• heating the furnace to a temperature in excess of the combustion temperature of the binder material;
• providing an oxygenated atmosphere within the furnace;
• containing the casting, with the at least a portion of the sand core therein, within the oxygenated atmosphere in the heated furnace to permit binder material to combust, whereby portions of the sand core are loosened and fall from the cavity of the casting while the casting is within the furnace;
• collecting the portions of the sand core which fall from the casting prior to the binder material being combusted therefrom to form a bed of loosened portions of sand core;
• fluidizing the bed of loosened portions of sand core such that sand is at least partially reclaimed from the bed of loosened portions of sand core, the fluidizing step including a step of burning binder material from the bed of loosened portions of sand core, whereby fumes are generated;
• capturing and at least partially incinerating the fumes within the furnace;
• and
• conveying the at least partially reclaimed sand away from the furnace.

A furnace system for heat treating a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the furnace system comprising:

• a heat treating region for receiving the casting therewithin;
• a support assembly for supporting the casting within the heat treating region;
• and
• a heating means for heating said heat treating region to a temperature sufficient to loosen portions of the sand core from the casting while the casting is in said heat treating region;
• a reclaiming region disposed below said heat treating region and in heat and gaseous communication with said heat treating region, wherein the loosened portions of the sand core fall under the force of gravity from the casting and said support assembly into said reclaiming region;
• and
• a fluidizer for fluidizing and reclaiming sand from the fallen portions of the sand core disposed within said reclaiming region.

The furnace system of claim 79,

• wherein the furnace system further comprises a hopper defining a hopper interior and including
• a hopper inlet that is oriented such that the loosened portions of the sand core fall into said hopper inlet and into said hopper interior, and
• a hopper outlet defining an opening below said hopper inlet, wherein said hopper outlet is constructed and arranged to pass the fallen portions of the sand core from said hopper interior, and
• wherein said fluidizer is proximate to said hopper outlet.