Abstract: There is disclosed a damper for controlling the flow of high temperature gases to respective hearth chambers of a multiple hearth furnace, for example, the damper being formed of temperature resistant ceramic plate having an air cooled shaft extending diametrically therethrough and insulated from the plate by a heat resistant ceramic fiber material.

Abstract: Method and apparatus for treating waste material in a counterflow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone.

Abstract: Furnace apparatus and method used to heat or incinerate materials which are being stirred or rabbled under atmospheres of corrosive gases, and which employs a new material of construction for fabricating rabble teeth to impart improved resistance to mechanical and thermal shock as well as improved resistance to attack by corrosive gases at elevated temperatures.

Abstract: Method and apparatus for treating waste material in a counter-flow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone.

Abstract: Method and apparatus for treating waste material in a counterflow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone.