Abstract: A shrouded rabble includes a blade having an active face and a backface with a shroud extending from the backface along a lower edge of the blade. The rabble is suspended above a perforated hearth for urging charge materials on the hearth from one location to another in response to relative rotation between the hearth and the rabble. The action of the rabble on the charge materials causes breakdown of the charge materials and accumulation of fines on the perforated hearth. The shroud defines a shroud chamber behind the blade and screens charge materials from the shroud chamber to expose accumulated fines on the perforated hearth. The charge fines thus become fluidized in an upflowing heating gas and exit the shroud chamber through at least one opening in the shroud, facilitating the flow of heating gas through the perforated hearth and into the charge materials. The opening may simply comprise one end of the shroud being open, or it may include a plurality of holes in the shroud itself.

Abstract: A high temperature furnace chamber includes a roller hearth for supporting and transporting workpieces to be heated. The rollers are supported at each end by a rotary sleeve having an inner diameter larger than the outer diameter of the rollers. Rotary movement of the sleeves transmits rotational forces to the rollers. Clearance provided between the rollers and the sleeves allows for roller dimensional variation during various furnace operating conditions.

Abstract: A ceramic tube recuperator for recovering energy from hot flue gases, in which a multiplicity of heat exchange elements connected to a cold air inlet manifold and a hot air outlet chamber extend upwardly into a flow passage for hot flue gases. Each heat exchanger comprises an inner open ended tube extending into the cold air inlet manifold, and an outer ceramic tube having a closed upper end and an open lower end communicating with the hot air chamber. An essential feature of the invention is that the lower end of the ceramic tube is sealed solely as a result of resting on an annular seal, so that the ceramic tube may be removed and replaced simply by lifting and lowering through an access opening in the flue passage.

Abstract: A system is described for precise monitoring and control of the carbon content of the atmosphere of a furnace such as a carburizer used in the heat-processing of steel parts. The disclosed apparatus includes a sampling system for withdrawing a gas sample from the atmosphere within a furnace and an analyzer for producing signals indicative of the partial pressures of at least two gaseous components such as carbon dioxide and carbon monoxide. The analyzer preferably utilizes selective absorption of narrow-band infrared radiation signals in determining these signals. A processor combines the signals indicative of partial pressures with parameters obtained from measurements of furnace temperature, and calculates carbon potential of the furnace atmosphere. The processor output is coupled with an atmosphere control which maintains desired levels of carbon potential in the atmosphere of the furnace by, for example, regulating the flow of an enriching gas to the furnace.

Abstract: A furnace for heat treating metal slabs or strips includes a heating chamber through which stock is passed in confronting relationship to an array of jet impingement radiation burners. Combustion is separated from the stock by flat refractory plates having a plurality of holes uniformly distributed thereover which direct uniform jets of combustion products upon the strip or slab. The jets of combustion products heat the work by convection. Also, the refractory jet forming plates are heated to radiance so that heat energy is transferred to the work by radiation.

Abstract: A crucible furnace for high-temperature melting of metals or other materials which includes a capped vessel for serving as a crucible to hold a charge of material to be melted, a solid baffle surrounding and closely spaced from the vessel to form a restricted passageway and a refractory wall surrounding and widely spaced from the baffle to form a combustion chamber. Fuel is supplied at the base of the combustion chamber and mixed with air preheated by a compact internal recuperator operative from exhaust gases exiting the restricted passageway. The fuel is burned in the combustion chamber, heating the baffle which in turn radiates heat to the vessel containing the charge. Several of the elements forming the combustion and heat transfer system also serve as structural elements providing rigid support to internal components when the furnace is upright and when it is tilted to pour off melt.

Abstract: A furnace for receiving continuously advancing stock in linear array is assembled from a number of independent furnace units. In each unit, a furnace chamber surrounds the advancing stock with a radiative wall. Each chamber is fired by gas burners which surround the stock at the chamber exit. The burners include a series of gas jets which feed the fuel, with or without air, radially into the chamber toward the stock and a series of air jets which are paired with the gas jets to feed combustion air axially into the chamber.

Abstract: A radiant tube burner mixes liquid fuel and/or gaseous fuel with air for combustion in a radiant tube to produce a quiet and stable luminous flame through the entire length of the radiant tube. A flame holding plate is positioned within the radiant tube to define a feed zone and a combustion zone. A liquid fuel nozzle positioned centrally in the plate directs fuel through the plate and into the combustion zone. The plate defines a series of apertures circumscribing the nozzle and another passage outward from the series of openings and concentric therewith. Combustion air is proportioned and admitted to the combustion zone through the series of openings and the passage. Gaseous fuel may be admitted to the combustion zone through the series of openings.

Abstract: A food cooker is illustrated in the form of a deep-fat fryer, in which the fat is isothermally heated to an operating temperature below a temperature range in which an unacceptably high rate of undesirable decomposition products formation occurs in the cooking liquid. The heat transfer process used is vaporization and condensation of a confined liquid essentially isothermally and substantially at the working temperature. Condensation of the heat transfer vapor takes place at an outer surface of the container for the fat. Heat is applied to the heat transfer liquid remote from the container, which having no heating element or elements intruding into its interior is easy to clean. Heat is transferred to the cooking fat by condensation of the heat transfer vapor essentially only as it is used by the load being cooked. Hot spots are minimized, so that the formation of undesirable decomposition products of the cooking fat is retarded.

Abstract: A food cooker is illustrated in the form of a deep-fat fryer, in which the fat is isothermally heated to an operating temperature below a temperature range in which an unacceptably high rate of undesirable decomposition products formation occurs in the cooking liquid. The heat transfer process used in vaporization and condensation of a confined liquid essentially isothermally and substantially at the working temperature. Condensation of the heat transfer vapor takes place at an outer surface of the container for the fat. Heat is applied to the heat transfer liquid remote from the container, which having no heating element or elements intruding into its interior is easy to clean. Heat is transferred to the cooking fat by condensation of the heat transfer vapor essentially only as it is used by the load being cooked. Hot spots are minimized, so that the formation of undesirable decomposition products of the cooking fat is retarded.

Abstract: Food preparation apparatus involves a heat transmitting zone and a heat source located remotely from the transmitting zone. Heat energy is transferred from the heat source to the transmitting zone by a fluid vapor which travels from the heat source to the transmitting zone, condenses upon the transmitting zone and then returns in a liquid state to the heat source.In one described embodiment of this invention, an oven is provided wherein a fluid enclosure within the oven walls confines the vapor which transfers heat energy from a central heat source to heat transmitting surfaces.