Abstract: A process and an apparatus for refining molten glass that includes a housing having a vertically oriented longitudinal axis and a transverse axis perpendicular to the longitudinal axis. Molten glass is received at an upper end of the housing and is discharged from a lower end of the housing. A guide extends at least partway across the housing and directs molten glass in a generally downward direction through the housing and in a parallel or oblique direction relative to the transverse axis of the housing.

Abstract: An object of the present invention is to separate CO2 gas generated in a cement-manufacturing facility in a high concentration and recover the CO2 gas. The present invention includes: feeding a cement material before calcination and a heat medium which has a particle diameter larger than that of the cement material and has been heated to the calcination temperature or higher in a medium-heating furnace (14), to a mixing calciner (12); and recovering the CO2 gas generated by the calcination of the cement material. The heat medium circulates between the medium-heating furnace and the mixing calciner. Another aspect of the present invention includes: feeding a cement material before calcination to a regenerative calciner (112) which has been heated to the calcination temperature or higher and has stored heat therein; and recovering the CO2 gas generated by the calcination of the cement material.

Abstract: The present device is a fluid bed regenerative thermal oxidizer configured to minimize dead spaces within it and eliminate the need for complex valve systems, which are typically required to move treated and untreated air across fixed beds. The present device can be a fluid bed regenerative thermal oxidizer comprising a vertical stack having a combustion chamber near its interior center and desorber shelves located within the vertical stack above the combustion chamber and adsorber shelves located within the vertical stack below the combustion shelves. Ceramic spheres can be used as heat sinks that flow from the desorber shelves, around the combustion chamber and onto the adsorber shelves and then back to the desorber shelves. In this way heat from the combustion can be captured by the heat exchange material on the desorber shelves and released to preheat untreated air on the adsorber shelves.

Abstract: A system and method for the calcination of minerals.

Abstract: A process for decarbonation of particles of raw meal, to be burnt in a clinkering kiln at a cement plant, the process includes: a) decarbonation of particles of raw meal, in a fluidised bed heat exchanger, the particles being suspended in a rising carrier gas including carbon dioxide, the fluidised bed heat exchanger having a solid heat carrier circulating counter-current relative to the carrier gas, to provide an effluent gas including carbon dioxide and decarbonated raw meal; b) separating the effluent gas and the decarbonated raw meal c) separating the effluent gas into a first and second part; cooling the first part of the effluent gas and recycling to provide carrier gas, d) isolating the second part of effluent gas e) recovering and re-heating the heat carrier and recirculating to step (a).

Abstract: A tobacco smoke filter which gives an acceptable vapor phase filtration and flavor delivery in the presence of a volatile flavorant (e.g. menthol), the filter containing activated carbon in which (1) pores of under 2 nm pore diameter (micropores) provide a pore volume of at most 0.3 cm3/g (NZ); and (2) (a) pores of 2 to 50 nm pore diameter (mesopores) provide a pore volume of at least 0.25 cm3/g (N2) and/or (b) pores of 7 to 50 nm diameter (larger mesopores) provide a pore volume of at least 0.12 cm3/g (Hg).

Abstract: Embodiments relate to production of hydrocarbons from an underground formation. More specifically, embodiments relate to a system and method for generating steam for heavy hydrocarbon production process. The indirect steam generation system uses moving hot solids (e.g. sand, metal spheres, etc) to produce steam from non-treated (dirty) boiler feed water. The solids are then transported to another vessel (e.g.combustor) where they are reheated and cleaned of contaminants before being recycled back to the boiler to produce more steam.

Abstract: A method for pyrogasification of organic wastes that employs a vertical furnace filled with metal masses in the shape of metal toroids (2) previously raised to a high temperature (500 to 1100° C.) and organic materials to be pyrolyzed. It also employs a furnace for heating toroids transported by an Archimedes screw driven by a gear motor, as well as a separator for recovering the mineral residues, whereby separation between the toroids and residues is effected with the aid of a screen and an Archimedes screw driven by a gear motor.

Abstract: The invention relates to a method for the continuous melting of inorganic salts and a furnace installation for realizing the method. Solid salts are fed into a furnace with the aid of a feeding unit. The salts contained in the furnace are heated. A flow of the salts is generating inside the furnace with the aid of a circulating unit. The flow generates a two-phase region containing solid and melted salt and a separate second region containing substantially solely a melt that is heated to the desired temperature. The melt is discharged from the separate second region simultaneous with the feeding of the solid salts into the furnace with the aid of a removal unit.

Abstract: An apparatus and method for the horizontal conveying of a dry powder is provided, notably useful for conveying heat from a heat-producing operation to a heat-consuming operation. In this application, heat is conveyed by a hot powder flowing through a vertically vibrated duct, the intensity of the vibration being sufficient to place the powder in a liquid-like state. The flow of powder is accompanied by a fall in pressure, and there is included a step for raising the pressure of the powder.

Abstract: The invention relates to a device for continuous heat treatment of granulated materials, especially to the crystallization of polymer granulate, such as polyethyleneterephthalate (PET) for example. The device comprises several adjacent fluidization chambers respectively provided with a sieve plate through which a fluidization gas used to fluidize the granulate can be insufflated into the respective chamber from below via a gas inlet, the gas being able to escape via a gas outlet in the top area of the device. The first chamber takes up the greater part of the overall volume of all chambers and neighboring chambers are, respectively, fluidically connected by product throughflow openings in the separating walls arranged therebetween.

Abstract: A heating device for burning fuel pellets (2) having a spherical combustion area (7), the surrounding wall of which is perforated (37), is disclosed. The combustion area (7) is surrounded concentrically by a wall(40) having perforations (36) and is spaced from the wall (10) of the combustion chamber. The space between the two walls (10 and 40) is utilized to hold the fuel pellets which are ignited by a heated medium directed from the outside towards both the walls (10 and 40).

Abstract: Technology for treating industrial and domestic waste which can be applied in the chemical industry as well as in the power generation sector as a way of using plastic and polymer waste. The method involves: melting down the plastic waste in an atomsphere of superheated steam and thermal destruction of the waste at a temperature of 400.degree.-500.degree. C. on a multi-layered inert material whose particles diminish in size, layer by layer in the direction of flow of the melt, from 3.83 to 0.12 mm; and the removal and condensation of the gaseous products.

Abstract: A thermal method for continuously processing waste having a calorific value and any degree of moisture, wherein waste is put in a flow of hot, heat-resistant, heat-exchanging material which is warmer than 100.degree. C. The heat exchanging material cools due to heat exchange, the waste dries and the non-evaporated waste components are heated. The cooled, heat-exchanging material is subsequently separated from the dried waste materials and the separated dried waste material is mixed with a percentage of the separated heat-exchanging material. The dried waste material and heat-exchanging material mixture is subsequently heated to pyrolyze waste material and heat the heat exchanging material in preparation for its subsequently use in the continuous process.

Abstract: A compact portable apparatus and method for heating gases for periods ranging from about one tenths of a second to several minutes to temperatures as high as 2700.degree. Celsius in 4 hrs. Graphite or metal oxide spherical pebbles which are placed in an externally thermally insulated cylindrical bed. The pebbles enclose and are heated by electrical resistive elements from which they are physically isolated. High heat storage density is achieved by designing the bed for high pressure loss operation and gas flow is in the downward direction. The bed is pressurized prior to initiating the gas flow with a quick acting valve or burst disc placed at the heater outlet. Typical applications are as a heat source for magnetohydrodynamic channels or wind tunnels. For magnetohydrodynamic applications a pulsed liquid seed metal injection method producing micrometer diameter liquid particles is disclosed.

Abstract: A sterilization apparatus for sterilizing medical instruments such as scalpels, tweezers, needles and the like utilizes an electrically heated inert material as the sterilizing media. Instruments to be sterilized are positioned in the inert material and become aseptic within 10 to 30 seconds. The sterilization apparatus includes a cylindrical metal tube which can be electrically heated in a short time to a high temperature (200.degree.-300.degree. C.). The sterilization apparatus also includes insulation surrounding the heated cylindrical metal tube and an insulated base. This insulation ensures that heat is conducted to the inside of the tube and is isolated from other parts of the apparatus, particularly, the electronic components. With this insulation, a compact sterilization apparatus can be made without damage to the apparatus components due to excessive heat.

Abstract: Heated surrogate medium is placed in heat transfer relation with high moisture content waste material where water is evaporated to steam. By agitating the mixture of waste material and heated surrogate medium, particulate matter from the waste material is entrained in the steam. A separator separates the steam and dried waste material and supplies the dried waste material to a burner for heating the surrogate medium. The separated steam flows to a stack or to the surrogate medium and oversized waste material discharged through an outlet of the drying zone for flowing additional particulate material from the waste material flowing through the discharge outlet back into the drying zone. The discharged surrogate medium and the oversized waste material are separated and the separated surrogate medium is recycled into the heating zone.

Abstract: The presence of the oxides of nitrogen in the exhaust gas leaving a regenerator is limited by injecting water or water vapour into the regenerator 1 during its firing phase and causing the water or water vapour to reach the combustion chamber 26 of the regenerator 1 by way its heat storage bed 11 which has been preheated during a previous heat collecting phase.

Abstract: A sterilizer for medical or dental instruments utilizes a reservoir of reusable heat transfer beads, a preselected quantity of which are released into an instrument tray containing instruments to be sterilized. The tray and beads are positioned within a heating column for sterilization and the tray with beads is thereafter removed to the top of the column for instant utilization. The beads are released through the bottom of the tray into the reservoir for reheating.

Abstract: A system is described for producing small uniform pellets of predetermined size which are substantially free of fines from mechanically dewatered sewage sludge and a means for controlling odor from the production of said pellets. The system includes a process and apparatus for mixing the dewatered sludge with previously dried recycled particles of said sludge. Drying the mixture in a thermal drier, separating a substantial portion of the dried solids from the drier off-gas. Clarifying said separated solids to separate the pellets of predetermined size, oversized pellets, and undersized pellets and particles, mechanically crushing the oversized pellets and admixing the crushed oversized pellets with the undersized pellets and particles and recycling said mixture for mixture with incoming dewatered sludge to the drier.

Abstract: A method and apparatus are disclosed for the treatment of paint sludge and for reducing volatile organic compound emissions from a paint spraybooth operation, thereby obtaining a recyclable material for use in new coating products. In such an operation, uncured paint resins mixed with volatile organic compounds are sprayed onto an article to be painted and at least a portion of the overspray is mixed with water to form a waste stream containing water, uncured paint resin, volatile organic compounds and inorganic substances. The method includes the steps of: removing a portion of the water and liquid volatile organic compounds from the waste stream; heating the resultant sludge to volatilize the residual water and liquid volatile organic compounds and to cure the uncured paint resin; collecting the residual solids stream, and removing all of the volatilized organic compounds from the resultant stream, thereby generating a volatile organic compound-free gas effluent.

Abstract: A system is described for producing small uniform pellets of predetermined size which are substantially free of fines from mechanically dewatered sewage sludge. The system includes a process and apparatus for mixing the dewatered sludge with previously dried, recycled particles of said sludge, drying said mixture in a thermal drier, separating a substantial portion of the dried solids from the drier off gas, clarifying said separated solids to separate the pellets of predetermined size, oversize pellets, and undersize pellets and particles, mechanically crushing the oversize pellets and admixing the crushed oversize pellets with the undersize pellets and particles, and recycling said mixture by mixing said mixture with incoming dewatered sludge to the drier.

Abstract: The invention provides an improved apparatus for use in processing wet scrap textile glass fiber into a dry flowable powder. The apparatus includes a unique inlet and outlet structure to prevent clogging during operation. The apparatus also includes a unique discharge unit for ground dry glass fines composed of a pair of rod gratings place proximate the outlet of the apparatus.

Abstract: A process is described for combining the disposal of sewage sludge and lime sludge economically by recalcining the lime sludge to product lime for municipal water treatment, and utilizing the excess heat from the recalcining process to dry and pelletize sewage sludge or to supplement the heat required to dry and pelletize said sewage sludge. The sewage sludge pellets then are produced in uniform sizes and have excellent value as a soil conditioner.

Abstract: A system is described for producing small uniform pellets of predetermined size which are substantially free of fines from mechanically dewatered sewage sludge. The system includes a process and apparatus for mixing the dewatered sludge with previously dried, recycled particles of said sludge, drying said mixture in a thermal drier, separating a substantial portion of the dried solids from the drier off gas, clarifying said separated solids to separate the pellets of predetermined size, oversize pellets, and undersize pellets and particles, mechanically crushing the oversize pellets and admixing the crushed oversize pellets with the undersize pellets and particles, and recycling said mixture by mixing said mixture with incoming dewatered sludge to the drier.

Abstract: A metal compressible bellows-type container or canister is used in a hot uniaxial pressing process with a mixture of high level radioactive nuclear waste material and a synthetic rock forming material filling the canister. The canister has a bottom wall, a convoluted bellows-like side wall, a lid or top wall and transverse metal apertured plates dividing the canister into three equally sized zones. Preferably the apertures are of a clover leaf configuration and are located at the center of the plates. Cylindrical liners can be provided to maintain a zone between each liner and the bellows-like side wall to prevent ingress of the particulate mixture of waste and synthetic rock forming material.

Abstract: The presence of the oxides of nitrogen in the exhaust gas leaving a regenerator is limited by injecting water or water vapor into the regenerator 1 during its firing phase and causing the water or water vapor to reach the combustion chamber 26 of the regenerator 1 by way its heat storage bed 11 which has been preheated during a previous heat collecting phase.

Abstract: A system is described for producing small uniform pellets of predetermined size which are substantially free of fines from mechanically dewatered sewage sludge. The system includes a process and apparatus for mixing the dewatered sludge with previously dried, recycled particles of said sludge, drying said mixture in a thermal drier, separating a substantial portion of the dried solids from the drier off gas, clarifying said separated solids to separate the pellets of predetermined size, oversize pellets, and undersize pellets and particles, mechanically crushing the oversize pellets and admixing the crushed oversize pellets with the undersize pellets and particles, and recycling said mixture by mixing said mixture with incoming dewatered sludge to the drier.

Abstract: Methods for continuous drying of sludges. Large scouring particles are added to a sludge to be dried to create a mixture which is passed through a rotary screw type indirect heat exchanger. The scouring particles are large relative to the particulates of suspended and dissolved solids which result from drying in the heat exchanger. During the process of drying and conveying the mixture through the heat exchanger the scouring particles continuously remove the particulate residue from the surfaces of the heat exchanger. It also appears that the particles assist in the actual heat transfer between the heat exchanger surfaces and the sludge by absorbing and subsequently releasing heat through relatively large surface areas. The scouring particles can be consumptive, that is, consumed in processes during subsequent handling of the residue, or nonconsumptive.

Abstract: A device for and method of working up etching and pickling liquids consisting of a vertical furnace having one or more vertical reaction spaces through which balls move at a maximum packing density.The furnace has a temperature gradient from the bottom (high) to the top (low). The reaction space and the balls consist of a material which is inert with respect to the liquid to be worked up. The liquid is introduced into the upper side of the furnace so that a film is formed in the heated surface of the balls. The salt dissolved in the liquid decomposes pyrolytically. The metal oxide is deposited on the surface of the balls and is removed therefrom after leaving the reaction space. The acid residue vapours are drained at the top and recovered in a separate absorber to the original pickling or etching acid.

Abstract: A method and an apparatus for drying or heat treating granular material fed in a continuous flow. The apparatus comprises a heating container having an inlet end and an outlet end. A heating source is located entirely within the container. An auger conveyor is disposed in the container adjacent the inlet end to displace a particulate medium, capable of retaining heat, from the inlet end to a heat chamber within the container. A transporting mechanism is provided in the heating chamber for showering the particulate medium in direct contact with a flame during a predetermined time so that the medium is quickly heated to an approximate desired temperature. A mixing and drying conveyor mixes and conveys the heated particulate medium with a humid granular material whereby to dry the material by heat transfer between the particulate medium and the granular material. A separator then separates the particulate medium from the granular material.

Abstract: A method of removing coatings from scrap glass is disclosed. The scrap glass is milled in the presence of particulate batch, preheated and fed to a glass melting furnace. The particulate batch aids in the milling of the scrap glass. The process removes the coatings from the scrap during preheating and provides clean material for melting.

Abstract: A method and apparatus for cooling waste gases of a temperature in excess of 800.degree. C. using radiant heat transfer to a plurality of fluidized beds. Solid particulate material is contained within a housing and divided into a plurality of fluidized beds by baffle means and fluidizing gas injected upwardly through the solids, without transfer of solids from the upper surface of a bed to adjacent beds. The hot waste gas is cooled by radiant heat transfer through the surfaces of the beds. Heated solids are cooled by either flow through the housing and cooling of the same outside the housing, or by coolant passed through heat transfer tubes that are positioned within the beds of solid particulate material.

Abstract: In reheating and conveying a granular heat carrier, such as sand, using a carrier gas, where the heat carrier may be utilized for desorption by heating a charged lumpy adsorbent, the heat carrier is circulated through a vertically arranged cycle loop. Initially the heat carrier is conveyed from a carrier gas inlet at the lowermost part of the loop to a separator at the uppermost point. After separation, the heat carrier flows downwardly under the effect of gravity through the loop passing, in turn, through a heater, a desorber where it is mixed with the adsorbent, and another separator where it is separated from the adsorbent, before the carrier returns to the carrier gas inlet for repeating the cycle. If sand is used as the heat carrier it can be conveyed upwardly through the loop by compressed air.

Abstract: A process for preheating particulate material is disclosed. The process also may be used for drying the particulate. The invention uses a heat exchange method that preferably employs furnace exhaust gases. In one embodiment, glass batch is preheated before being fed to a melting furnace. The invention involves the use of glass-ceramic materials as the heat exchange media.

Abstract: Cold, wet gypsum is admixed to a moving bed of hot solid particles of a heat-retaining material. The mixture is fed to a moving bed type drier where it is agitated while the released vapors are withdrawn. After discharge from the drier, dry gypsum is separated from the heating particles and the latter are recirculated into a heater. Preferably, flue gases from a combustion chamber are employed for heating the particles, which are preferably in the form of steel balls.

Abstract: A process and apparatus for drying or heating a particulate material by means of heat transfer media which is brought into direct contact with the particulate material within a continuously rotating cylindrical drum. The particulate material flows in one general overall direction through the drum and the heat transfer media flows in a generally opposite direction through the drum. The particulate material is subjected to heat treatment by repeatedly coming into direct and immediate physical contact with the heat transfer media in the course of flowing through the drum while it is subsequently separated from the heat transfer media per revolution of the drum.

Abstract: The invention discloses a process and apparatus for the heating or cooling of light solid particles having a low free-fall speed, by means of flowing gas-solid exchangers. The process makes it possible to heat or cool light solid particles dispersed in a gas flow by contacting them with a countercurrent flow of heavy solid particles having a greater final free-fall speed and that are hot or cool in relation to the light particles, thus effecting a heat transfer between the particles.

Abstract: A method and apparatus for preheating particulate glass batch comprises a rotatable drum for mixing the batch with particulate heat transfer media in a heat transfer relationship where the batch is separated from the media in a media exit vestibule having a screen through which the batch passes and having compartments mounted for rotation about the axis of the drum for lifting the separated batch to the batch inlet conduit where it is directed back into the drum.

Abstract: An improved apparatus and method for feeding heat carrying solids into a solids heater. A feed conduit is provided which may be removably attached to a solids heater shell. The mounted feed conduit includes an outlet portion disposed within a heating chamber which is defined by the heater shell. A jacket tube is sealed around the feed conduit to provide cooling against high temperatures. Further, inlets and outlets are provided for introducing and removing cooling medium from the cooling zone defined by the space between the jacket tube and feed conduit. The feed conduits are removably attached to the heater shell by way of mounting tubes located in the heater shell roof. For inclined heater shell roofs, the length of the mounting tubes are varied to provide common elevational mounting of a single uniform removable feed conduit.

Abstract: A solids-gas contact vessel, having two vertically disposed distinct reaction zones, includes a dynamic seal passing solids from an upper to a lower zone and maintaining a gas seal against the transfer of the separate treating gases from one zone to the other, and including a stream of sealing fluid at the seal.

Abstract: The present invention provides a method and apparatus for conveying very fine material, for example, a material where 100 percent of the material is less than fifty microns in diameter, and 50 percent of the material is less than five microns in diameter. The method utilizes a vibratory conveyor, on the surface of which is formed a bed of relatively large particulate material (50 mesh or larger in diameter, for example), and the very fine particles are introduced onto the bed. Under vibratory conveying motion, the fine material filters into the interstices formed by the larger particles and thus the fine material is conveyed along with the coarser material to a point of delivery. Another aspect of the invention includes the step of separating the fine material from the particulate material and recirculating the latter. Also, the recirculating particulate material may be chilled during recirculation and thus acts as a cooling agent when reintroduced to the conveyor.

Abstract: The present invention is directed to a process for transferring heat between two gases having different temperatures through the intermediary of a solid heat-carrier, which process may be possibly applied to the treatment of a raw cement. In said process a powderous or granular solid material is employed as the solid heat-carrier, the gases circulating in two different cascades comprising batteries of cyclones and said heat-carrier is used to recover at least a part of the heat carried along by the hot fumes issuing from a clinkerization furnace.

Abstract: A reaction vessel for regenerating particulate adsorbents has a bottom outlet and top inlets for admission of the adsorbent to be regenerated by being heated to a regeneration temperature, and for a particulate regenerating material at a temperature above the regeneration temperature. The mixture of the adsorbent with the regenerating material forms a bed in the reaction vessel and is continuously withdrawn through the outlet so that the bed descends toward the latter and is replenished from above under the formation of a cone at the upper region of the bed. A plurality of tubular baffles coaxially surrounds the inlets which are also coaxial with one another, each of the tubular baffles penetrating into the bed in the region of the cone and retards the flow of the particles of the mixture down the slope of the cone in that the particles must pass underneath the baffle to flow to the next baffle.

Abstract: An apparatus for heating a carbonaceous material to produce a gas in which the carbonaceous material and a heated inert heat exchange medium are passed into a reactor vessel for mixing and for transferring the heat from the heat exchange medium to the carbonaceous material to produce gas. An outlet opening is provided through the reactor vessel for discharging the gas and an impingement plate is disposed in the interior of the vessel and extends across the outlet opening in a spaced relation thereto in the path of the gas. As a result the gas impinges against the plate before discharging from the outlet opening to separate solid particles from the gas.

Abstract: A process and apparatus for treating materials, such as solid, particulate material, wherein the particulate material is introduced into a heat transfer medium, the density of such medium being different from that of the particulate material and the temperature of such medium being higher than that of the particulate material when so introduced. The particulate material, the individual particles of which are preferably introduced separately, travels through the medium and becomes heated thereby to a generally flowable state. The flowable particles of the particulate material thereupon leave the fluid and coalesce to form a flowable mass thereof external to the heat transfer medium.

Abstract: A fuel saving improvement in conventional home, commercial and public building heating furnaces comprising the inclusion of heat absorbing members such as stones on rod mesh trays in the normally substantial amount of unoccupied space above the furnace combustion chamber. The trays carrying the heat absorbing members are held, one above the other, by a metal support frame resting on the refractory material of the combustion chamber. The stones or other heat absorbing members are each at least three inches in cross sectional dimension and in spaced relation to each other. And the heat absorbing members in each tray are positioned above the respective open spaces between the stones in the next lower tray to cause a tortuous path for the heat and energy passing from the heating flame in the combustion chamber to the furnace flue opening. The heat absorbing members thereby absorb heat from the heating flames which would normally be lost to the flue opening during "ON" periods of the heating flame.

Abstract: A method and apparatus for heating articles, such as eyeglass frames, includes a bed of heat retentive beads supported above a plenum chamber by a mesh or screen. Heated air is delivered to the plenum chamber at low velocity and high volume for flowing upwardly through the bed for heating the same. The air is directed through the plenum chamber by bodies which act as baffles as well as a heat sink.

Abstract: A powdery substance in suspension state is heated with the high-temperature combustion waste gas exhausted from a glass tank furnace, and the air for combustion is heated with the thus heated powder substance. When the powdery substance employed is a raw material for preparing glass, the raw materials for preparing glass and the air for combustion to be supplied to the glass tank furnace are both heated therewith thereby contributing to effective recovery of the heat of the combustion waste gas.

Abstract: Methods and apparatus for roasting a product with a heated granular bed are disclosed. A granular bedding, heat transfer material such as salt or the like contained within a rotatable heating chamber is directly exposed to a heat source which directs heat into the interior of the heating chamber. Heated granular material is then conveyed to a separate product roasting chamber and mixed with incoming particles of a product to be roasted. Internally disposed auger and flighting means facilitate movement of the commingled granular material and product through the roasting bin in response to rotation thereof. Separation means at the output of the roasting bin separates the processed product from the granular heating medium, and continuously returns the granular material to the heating bin for repetition of the process cycle. In one form of the invention the heating chamber is coaxially disposed internally of the rotatable roasting chamber to maximize thermal efficiency.