Rotary hearth furnace and method of loading and unloading the furnace

A method of operating a rotary hearth furnace having a heated chamber and having an intermittently rotatable hearth in said chamber for indexing workpieces step-by-step around a circle, said hearth having a plurality of angularly spaced workpiece stations which are spaced equally from one another by an angular distance F, said method comprising periodically indexing said hearth through equal steps each having a preselected angular distance G which is a whole multiple of said angular distance F whereby one station stops at a predetermined loading position each time the hearth dwells between successive steps, and placing a workpiece in the station which stops at the loading position when the hearth dwells, said method being characterized in that said angular distance G is selected such that the quotients resulting from dividing 360 degrees by G and by 1/2 G are non-integers so that successively loaded workpieces are placed in non-adjacent stations during one revolution of said hearth and are placed in stations located between loaded stations during the next revolution of said hearth.

A method as defined in clam 10 in which said unloading position is approximately, but not exactly, diametrically opposite said loading position.

A rotary hearth furnace having a chamber, means for heating said chamber, an intermittently rotatable hearth in said chamber for indexing workpieces step-by-step around a circle, said hearth having a plurality of angularly spaced workpiece stations which are spaced equally from one another by an angular distance F and which periodically dwell in a loading position, means in said loading position for placing a workpiece in each station when the station dwells at the loading position, and means for indexing said hearth through equal steps each having a preselected angular distance G which is a whole multiple of said angular distance F and which also is such that the quotients resulting from dividing 360 degrees by G and by 1/2 G are non-integers whereby successively loaded workpieces are placed in non-adjacent stations during one revolution of said hearth and are placed in intervening stations during the next revolution of said hearth.

A method of operating a rotary hearth furnace having a heated chamber and having a rotatable hearth in said chamber for advancing workpieces around a circle, said hearth having a plurality of angularly spaced workpiece stations which are spaced equally from one another, said method comprising the steps of rotating said hearth in one direction within said chamber, and placing workpieces in said stations at said loading position, said method being characterized in that successive workpieces at said loading position are placed in non-adjacent stations during a first revolution of said hearth and are placed in intervening stations during a second revolution of the hearth.