Abstract: Modular, conveyor-type heat exchange apparatus is provided which is especially adapted for handling large volumes of shale rock and preheating incoming raw shale using hot, spent shale from a commercial processing operation. The apparatus includes an elongated heat exchange zone having a plurality of separate, interconnected, insulated modules; two superposed, oppositely moving sections of an endless conveyor pass through the zone and respectively support hot and raw shale material for heat exchange therebetween. The conveyor includes spaced, interconnected, shale-supporting triangular elements which facilitate gas flow between the conveyor sections in the heat exchange zone. In preferred forms, the modules present restricted inlet and outlet throats, and are provided with slow moving fans for circulation of air currents between the conveyor sections without creation of chimney-like drafts along the length of the modules.

Abstract: A process and system to dry wet sewage sludge with hot sand and to burn the dried sludge. The sand is heated in a heating device by burning dried sludge, and the hot sand is mixed with wet sludge in a drying device. Thereby moisture is driven from the wet sludge to dry it. The dried sludge and sand are separated, and the sand returned to the heating device while the dried sludge is burned to heat the sand.

Abstract: A novel kiln with overlying beds arranged about a central hollow shaft carrying rabble arms attached thereto and with alternate apertures formed in the floors between adjacent stories adjacent the hollow shaft and adjacent the periphery of the floor and with treatment gases being supplied through such orifices in a direction opposite to the direction in which the material moves through a furnace and further providing hot gas feed conduits located in the walls of the furnace in one or more stories and directed in a generally tangential direction relative to the story floors.

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: In a top-shaped lime kiln which comprises a slowly rotatable platter-shaped kiln bed having a cylindrical calcined lime-cooling chamber extending downward for connection to the central opening of said kiln bed; an immovably hung round lid having a fuel combustion chamber extending upward for connection to the central opening of said lid; and raw limestone granules-feeding chutes 19 opened to an annular gap 12 formed between the peripheral walls of both bed and lid; an improvement wherein a hot-gas-circulating apparatus is fixed in the maturation zone of the cooling chamber, and automatically reciprocative pushing rods are inserted into the limestone granule layer formed on the rotary kiln bed through the peripheral wall of said bed or lid so as to let fall the calcined lime into the cooling chamber.

Abstract: Method and apparatus for the heat treatment of volatile containing materials in a rotary hearth type furnace wherein the flue gases emanating from the calciner are employed to create either a positive or negative pressure within the calciner hearth as well as the soaking pit area of the said calciner.

Abstract: A scraper flight conveyor for preheating thermoplastic bulk material and feeding it to a screw extruder comprises a succession of controllably heated slideways arranged in superposed series, a plurality of scraper flights in sliding contact with each slideway and spaced along a path of travel over the surface thereof, and a drive operable to move the scraper flights on each slideway along the path of travel. The scraper flights push discrete portions of the thermoplastic bulk material along the path of travel. The delivery rate of the material to the slideways is controlled.

Abstract: A method and apparatus for incinerating waste material in a multiple hearth furnace having a plurality of vertically spaced hearths wherein waste material is introduced to the furnace at the top thereof and moves downwardly in a generally serpentine fashion moving alternately inwardly and outwardly across the hearths and is discharged at the bottom of the furnace, and including the steps of introducing towards the lowermost hearth thereof air in a quantity less than that theoretically required for complete combustion of the material being processed, thereafter at successively higher hearths ascertaining the temperature at each hearth and adding air thereto in quantities only sufficient to support combustion thereon, and on each hearth in the middle portion of the furnace adding only enough air to each hearth so as to maintain the temperature on that hearth under a maximum predetermined limit, and on the hearths towards the top of the furnace reducing the quantity of air added, and thence discharging the exhau

Abstract: The invention is directed to method and apparatus for treating waste material containing alkali metal in a counter-flow furnace wherein the waste material to be processed is introduced at one end thereof and the processed material is discharged from the other end, while simultaneously air is introduced and the gases of combustion are caused to flow in a 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, and a fixed carbon burning zone, and wherein a maximum temperature is maintained in the furnace below about 1400.degree. F. directly adjacent the surface of the bed of material being processed.

Abstract: The present invention is directed to 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 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, a method characterized by the step of adding an oxidant including water vapor to the fixed carbon burning zone.

Abstract: An insertable and reversible rabble tooth for the rabble arms of furnaces including specially shaped wedges to clamp the rabble teeth to the rabble arm in either in hearth condition or in out hearth condition by reversing the positions of the wedges and reversing the positions of the teeth held by the wedges.

Abstract: The invention relates to a method and apparatus for the heat treatment of materials on a traveling hearth mounted on a horizontal plane and rotated on a vertical axis within a substantially air-tight enclosure. The materials on the hearth are deposited thereon in separate and distinct rows and retained in separate rows while undergoing heat treatment within the enclosure. The material in one of said rows is capable of evolving volatiles when the materials are subjected to a heat treatment and the evolved volatiles rise and are dispersed in the upper portion of the enclosure where the same will combine with an oxidant such as air and/or oxygen which is admitted into this portion of the enclosure. The mixture of evolved volatiles and oxidants such as air and/or oxygen will combust in the upper portion of the enclosure.

Abstract: A hearth cleaning apparatus includes a wheeled car movable along a floor at the side wall of a reheat furnace wherein metallic workpieces are heated while they are advanced along the furnace hearth. The car is latched to the side wall of the furnace at any one of the normally-closed openings therein. An inverted U-shaped spacer slab is passed through the furnace between two workpieces for access to the hearth. An elongated digging bar which may be cooled by the internal flow of water is supported by the car and advanced through an opening in the side wall of the furnace to engage and loosen slag or other materials adhered to the soaking hearth while exposed by the spacer slab. The car includes a vernier elevation adjustment for the digging bar at the point of support adjacent the furnace and a course elevation adjustment for the digging bar at the opposite end of the car. The digging bar is propelled along the furnace hearth by a pair of pinch rolls.

Abstract: Coal dust comprising coal particles of 40 mesh or less may be utilized as a fuel for stable combustion by aspirating the dust in fluidized suspension for delivery to a turbulent reservoir and aspirating the suspension from the reservoir for delivery to a combustion zone.

Abstract: A system for controlling the operation of a multiple hearth furnace over a diverse range of operating conditions at a minimum level of energy consumption. Relatively low temperature gases are controllably recirculated from the drying zone to the combustion zone of the furnace, and/or gases are controllably discharged from the combustion zone and/or drying zone to regulate drying zone temperature, combustion zone temperature and the quantity of excess air required to provide optimum furnace operating conditions. The system is particularly useful for controlling the incineration in a multiple hearth furnace of sludge from waste water treatment plants.

Abstract: This application describes a continuous method of removing polyvinyl chloride insulation or other volatilizable material from items such as copper wire without producing undesirable by-products. The method involves the pyrolysis of the insulation on the wire in a fluidized bed reactor charged with small particles of calcium carbonate. The calcium carbonate reacts with the gaseous chlorine from the insulation to produce calcium chloride which then is collected and can be used for snow removal, road construction, and the like. After removal of the insulation, the copper wire is cooled and cleaned. The products of combustion are passed through an afterburner to a HCl scrubber containing CaCO.sub.3 where any remaining chlorine is reacted with calcium carbonate to produce CaCl.sub.2. The application also describes apparatus for moving the items across the heated reactor.