Abstract: A burner unit for heating a gaseous medium includes a heat exchanger provided with tubes, a space between the tubes connected on the upstream side to a feed duct for the gaseous medium; a combustion chamber connected to the downstream side of the space between the tubes; a burner placed in the combustion chamber; and a fuel supply duct connected to the burner. The side of the combustion chamber remote from the heat exchanger is connected to a first end of the tubes; and a flue gas outlet duct is connected to the other end of the tubes. The elongation of the tubes forming part of the heat exchanger renders the use of a conventional tube plate superfluous. Thus, damage resulting from thermal stresses is avoided.

Abstract: A furnace includes a generally cylindrical combustion chamber that is open at one end for receiving a single port inshot target burner. The target burner includes a flame spreader for lowering the heat energy and temperature of the gas flame so as to reduce NO.sub.x emissions. The flame spreader includes a plurality of rods affixed to the target plate or disc.

Abstract: A method and an apparatus for producing semiconductor devices in which a semiconductor wafer is adhered to an ultraviolet sensitive tape, the adhesion force of which decreases upon irradiation with ultraviolet rays, the ultraviolet sensitive tape being adhered to a ring frame so that the semiconductor wafer is fixed to the ring frame with the ultraviolet sensitive tape. Successive semiconductor wafers thus fixed to respective ring frames are subjected to a series of steps including dicing, breaking, and ultraviolet irradiation for reducing the adhesiveness of the ultraviolet tape. The semiconductor wafer, broken and divided in dice and held by the ultraviolet sensitive tape with reduced adhesiveness, is sent to a next step, such as a die-bonding step.

Abstract: A standard atmosphere furnace constructed of a steel casing formed as a cylinder with fibrous insulation attached is operated as a vacuum furnace. A plurality of radiant, fuel-fired ceramic heat tubes positioned in a centered but circumferentially spaced arrangement provides heat input to the furnace to permit it to operate at high, vacuum associated temperatures. The ceramic tubes are vacuum sealed to the furnace case by an elastomer seal/water jacket arrangement which uses an outboard clamp arrangement to establish a ceramic-to-metal contact to permit thermal cooling and prevent tube-flange movement so that the integrity of the elastomer seal can be maintained. In addition, an articulated joint connector is provided so that the tube can be supported in a pivotable manner permitting thermal movement while reducing tube stress to prolonged tube life.

Abstract: A low-voltage electric heating device for application in a carburizing furnace is provided with an outer housing or sleeve for replaceable disposition within the furance, the outer housing radiating heat directly into said furnace; at least one current path conductor is positioned within the outer housing, the current path conductor being electrically connectable to a source of power and electrically insulated from a substantialy part of the outer housing. The heat radiated from the heating device is concentrated in the lower part because a current path has in series at least the current path conductor and at least a corresponding part of the outer housing, the resistance of the lower part of the outer housing being relatively large with respect to the remainder of the current path.

Abstract: A linear combustion emitter regenerator process capable of operating at high temperatures for sustained periods of time, that includes flowing reactants including fuel and air to a combustion zone; adding regenerated heat to at least one of the reactants flowing to the zone; combusting the reactants at the zone to produce combustion products at high temperature, to heat radiant emitter; operating the emitter to radiate energy from the zone passing selective wavelengths of said radiated energy spectrum through an optical filter and converting the radiation from the emitter into photovoltaic-produced electricity; mounting optical filter on water-cooled window to act as a heat shield to protect photovoltaic cells from overheating; reflecting back to the emitter portions of the spectral emission not able to activate the photovoltaic cells; extracting heat absorbed by liquid-cooled window by means of a heat exchanger to transfer heat to incoming combustion air; extracting heat from the combustion products for retu

Abstract: A furnace includes a generally cylindrical combustion chamber that is open at one end for receiving a single port inshot target burner. The combustion chamber is connected to a heat exchanger through which the combustion products are drawn by an induced draft blower. A flame retention ring is provided in the target burner to aid the flame in attaching to the outer surface of the flame retention ring and thereby improve flame lifting characteristics. Also, a frustro-conical member surrounds the end of the target burner within the combustion chamber for directing air into the combustion zone to enhance the combustion process.

Abstract: An improved industrial furnace employing a new and unique heat transfer arrangement is disclosed. The furnace is a closed end cylindrical chamber with a circular, concentrically positioned plate dividing one side of the furnace into a fan chamber containing a fan and the other side of the furnace into a heat treat chamber containing the work. The plate has a central under-pressure opening and its outer circular edge is spaced from the cylindrical wall to define an annular space which is non-orificing. Fan rotation in the fan chamber produces an annulus of wind mass swirling at high circumferential speed which axially travels through the non-orificing space towards the closed end of the heat treat chamber at slow speed. Heating elements extend through the non-orificing space into the heat transfer chamber and are constantly impinged by the swirling annulus wind mass to effect good heat transfer therewith.

Abstract: A radiant tube furnace has a pair of regenerative burners firing alternately into opposite ends of the tube. There is a respective inlet at each end of the tube for admitting gas to the tube immediately adjacent to the wall thereof and these inlets communicate via a duct so that products of combustion are drawn from one end of the tube and introduced into the opposite end of the tube, where the burner is firing.

Abstract: A radiating tubes system of the double-pin type that is in the shape of a "W" used in heating ovens, notably in continuous heating ovens for metallic bands, for providing the heat transfer between combustion bases released by a burner and the products to be heated. In the invention system, the burner is positioned in the lower branch of the tubes; the support device of the cold bend, in the upper portion of the tubes, is made in the form of a simple bearing base; the cold bend and the hot bend are connected to one another without a connecting-rod type intermediate part, and the intermediate bend and the lower tube are connected to one another with a settable play between these two elements.

Abstract: An improved radiant tube heater is disclosed utilizing a burner operating with an excess of either gas or air together with the remote injection of the required air or gas to match the excess and produce a staged combustion.

Abstract: The invention relates to an apparatus for the heat treatment and/or the drying of a web of material 1 passing continuously through. In this case the web of material 1 is treated on one or both sides with infrared radiation. The infrared radiators 6, 7 can be adjusted in their radiation capacity over the width of the web of material 1 by being heated by a plurality of individual hot-gas streams which are guided parallel to the web of material 1, can be adjusted to differing temperatures or can sweep at differing flow rates over the rear sides of radiating plates 6a, 7a of the infrared radiators 6, 7.

Abstract: The present invention relates to method and apparatus for heating a strip of metallic material in a continuous annealing furnace and more particularly to an improvement relating to a method and apparatus for heating a strip of metallic material in a continuous annealing furnace in which annealing of the strip is continuously carried out in such a manner that a gas serving to adjust temperature of the strip, is blown toward the strip through a plurality of gas jet nozzles which are arranged on one side or both sides of the strip, wherein the temperature and flow rate of the strip are properly determined to a required level in response to the changing of the operating conditions such as the heat cycle, line speed, thickness of strip, width of strip and the like.

Abstract: A burner unit is used for firing, for example, formed ceramic bodies in a firing furnace. The burner unit includes a burner tile assembly provided in a furnace wall and a burner connected to the burner tile assembly and provided out of the firing furnace. The burner is integrally provided with a connecting burner tile assembly having a tapered step. The burner tile assembly is also provided with a tapered step. The tapered steps of the connecting burner tile assembly and the burner tile assembly are connected through a sealing material to connect the burner to the burner tile assembly. With this arrangement, the burner unit reduces heat dissipation due to a burner construction and enables maintenance to be effected during operation of the burner.

Abstract: A fuel fired heat treating furnace having an imperforate inner shell for containing a work load in isolation. The shell is made of a refractory material which provides a good heat exchange from the outside to the inside. A multiplicity of hot gas streams is directed under pressure against the outside of the shell by means of a circulation system which includes a plenum, a fan within the plenum and a plurality of apertured distributor tubes extending from one end of the shell to the other. Fuel burners exhaust combustion gases into the system on the discharge side of the fan where the gases mix with returning gases from the intake side of the fan and are fed into the distributor tubes.

Abstract: A dual burner bidirectional radiant tube heater is disclosed utilizing single throat eductors for both the supply of combustion air to the burners and for the exhaust of the products of combustion from the burners.

Abstract: The present invention relates to a low NOx radiant tube burner. The radiant tube burner consists of; a primary combustion chamber which is located outside of the furnace and having an injection outlet of the combustion gas located approximately more inside of the furnace than the bung of the radiant tube, a primary fuel nozzle which injects primary fuel into the primary combustion chamber, and a secondary fuel nozzle which is surrounded with refractory material and injects secondary fuel into the radiant tube from the area adjacent to the injection outlet. Approximately the total amount of the combustion air is supplied into the primary combustion chamber with primary fuel under a high excess air ratio creating primary combustion. The low concentration of oxygen remaining in the primary combustion gas combined with the secondary fuel creates secondary combustion.

Abstract: An inner tube for a radiant tube for recirculating burnt gases supplied by a burner, consisting of a plurality of axially aligned assembled tube sections arranged end to end whereas the assembling means consist each one of a sleeve coaxially surrounding the ends of said sections to be interconnected and the radially inner surface of which comprises in the middle of its length an annular collar projecting radially inwards and fitting between both tube sections to be connected together, the inner surface portions which are located on either side of the collar widening gradually towards the sleeve ends.

Abstract: A radiant wall (6) for heat exchangers, muffle kilns and similar equipment, consisting in a succession of rollers (11) suspended side by side in such a way as to create a physical barrier for the separation of two environments accommodating media between which an exchange of heat is brought about.

Abstract: A gas-fired combination steam and dry oven has an oven cavity that is heated by heat exchange from one or more fire tubes and a boiler that is located outside the oven cavity and is heated by heat exchange from one or more other fire tubes. Both the oven and boiler fire tube heat exchangers employ natural draft gas burners. The combination oven can be operated as a forced-air convection oven, a forced-flow convection oven circulating superheated steam, or a steamer circulating saturated steam. Sensors in the oven supply information to a microprocessor that controls the gas burners to maintain an oven temperature within 5.degree. F. or less. Sensors of the level of water in the boiler assure that the water level stays within predetermined limits. Tray stops keep foods and the trays containing them away from the walls of the oven to permit free circulation of air, saturated steam, or superheated steam.

Abstract: The radiant tube burner assembly comprises a radiant tube having a burner leg and an exhaust leg. A plenum for mixing combustion air and products of combustion from the exhaust leg is positioned to direct the resultant mixture into the burner leg. A jet pump for directing high velocity combustion air through a nozzle and along a central longitudinal axis of the plenum aspirates the products of combustion from the exhaust leg through a duct in registry with the plenum and the exhaust leg. A restricted orifice associated with the duct is dimensioned and sized in relation to the jet pump nozzle to control the amount of products of combustion aspirated to the plenum. A conventional fuel source including a fuel pipe and conventional exhaust means also form a part of the assembly.

Abstract: An improved heat transfer arrangement for use in a unique multi-function, industrial heat treat furnace which employs a sealed, closed end, heat exchanger shell member containing the work. The heat transfer arrangement includes a totally contained, internal recirculation system which develops an especially configured annular jet stream that produces highly efficient, convective heat transfer with the shell member. After heat transfer between the entrained gases in the jet stream with the shell member has occurred, the jet flow is reversed at one end of the shell and impinged against the workpiece, the spent stream being reformed into the annular jet at the opposite end of the shell member.

Abstract: A housing open at both ends has opposed concaved radiant emitter walls which are disposed on opposite sides of a conveyor for defining a drying chamber through which the conveyor moves freshly coated objects. Heated air from a closure is fed to outer cavities in the housing and this air passes inwardly through nozzle ports in partition plates to impinge and heat the walls. A major portion of the air returns to be reheated in the closure. Fresh air is introduced, in heat exchanging relationship to the heated air, to ducts which discharge into the drying chamber. Overhead fans selectively circulate turbulent or laminar air in the drying chamber. Air is withdrawn from both the drying chamber and the outer cavities via over head exhaust ducts. A computer and sensors control the temperature of the emitter walls by controlling the heating of the heated air.

Abstract: A heat treatment apparatus which comprises a treatment chamber formed with heat insulating walls, a graphite heater installed in the treatment chamber, a gas supply port supplying non-oxidizing gas to the chamber and an exhaust port for carrying gas out of the chamber. At least a part of the inner side of the heat insulating walls is made of graphite group material of bulk density of not less than 0.3 g/cm.sup.3. The ratio of the outer surface area of the graphite heater (Ah) to the surface area of the chamber-facing side of the heat insulating walls (Ai), Ah/Ai is within the range of 0.1-0.4, and the relationship between the surface area of the graphite group material (Ar) and (Ah) is Ar>Ah. By this structure, the temperature of the heater to be set for heat treatment of workpieces can be decreased, and the life spans of the heater and the heat insulating walls can be increased.

Abstract: A drying furnace for use in coating drying in which a hot gas recycling duct for emitting radiation heat is disposed on the inlet zone of a tunnel-like furnace main body and resin-removing ducts are disposed along the ceiling of the inlet zone and the exit zone of the furnace main body respectively, wherein the furnace main body is turned in a U-shaped configuration so that the inlet and the exit thereof are arranged side by side, and the hot gas supplied to the hot gas recycling duct is supplied to each of resin-removing the ducts. Resinous substances can surely be prevented from forming and depositing at both of the inlet and the exit of the furnace and the cleaning work for the resin-removing ducts can be saved.

Abstract: A conveyor oven for cooking or heating food products and other items which utilizes a (preferably non-metallic) heat sink to absorb energy from an infrared heat source and then re-radiate the heat into the oven. Control over the degree and distribution of heat is exerted by bottom side vent holes and bottom sliding plates which control the size of the vent hole openings and top rotary flaps which deflect heat onto the food products. A method of cooking or heating food products and other items utilizing such a conveyor oven is also provided.

Abstract: A gas-fired radiant tube that employs heterogeneous catalytic combustion, and a high combustion efficiency, low NO.sub.x catalytic combustion radiant tube heating system, incorporating the radiant tube, are disclosed. In the system, essentially mirror image, combined inlet/exhaust units containing heat regenerator units are connected at opposite ends of the catalytic combustion tube. Combustion flow is cycled back and forth through the units and the combustion tube so that during any given cycle the hot exhaust gases heat the regenerator in the exhaust side of the flow for preheating the inlet gases during the next, reversed flow cycle and the natural gas fuel is completely oxidized. Thus, the cycled flow completely consumes the fuel and constantly preheats inlet air so that the sytem provides both high combustion efficiency and high thermal efficiency.

Abstract: A continuous heat treating furnace for heat treating a ferrous metal work in a protective atmosphere, including a furnace separated into a charge chamber and a heat treating chamber by a partition door and provided with a transport device for transporting the work. A first heating device, a recirculating fan and a gas purge device are provided in the charge chamber, while a second heating device is provided in the heat treating chamber supplied with the protective atmosphere, whereby the work is preheated through convectional heat transfer in the charge chamber simultaneously with high-temperature purging of the charge chamber and then, is heat treated under the protective atmosphere in the heat treating chamber.

Abstract: A procelain enameling furnace includes a combined entrance/exit zone, an air seal section, a radiation/convection heat transfer section, and a heating section. The entrance/exit zone receives an incoming cool ware and discharges an outgoing hot ware at substantially the same location. The air seal section prevents loss of heat from the furnace through the entrance/exit zone. In the heat transfer section, the incoming ware is parallel to and travels in the opposite direction to the outgoing ware for transferring heat therebetween by radiation and convection. The heating section includes a pre-heating zone and at least one heating zone. The pre-heating zone is formed of U-shaped heat exchanger tubes through which the incoming ware passes following the heat transfer section. The heating zone is formed of U-shaped radiant heating tubes for heating the cool ware following the pre-heating zone.

Abstract: This invention relates to apparatus for melting metal, and particularly for melting lead. The apparatus 10 comprises a reservoir 11, a heat exchange tube 12, which extends through the reservoir, a burner nozzle 13 at the inlet 14 of the tube and a flue 15 at the outlet 16 of the tube 12. Heating of air in the tube induces a draught through the tube and up the flue 15, so that air is drawn into the tube at the inlet 14. This flow of air causes the flame from the burner nozzle 13 to be sucked downwardly into the tube. The tube, and hence lead surrounding it, is thus heated.

Abstract: A heat recuperator and a method for recuperating heat from a furnace having a nozzle-mix burner to enhance the efficiency of combustion of one or more burners associated with the furnace. The recuperator comprises an exhaust tube which is connectable to a furnace combustion chamber for receiving heated exhaust gas therethrough. The exhaust tube has an outer cylindrical wall and an inner metallic tube concentrically supported therein. An annular space is defined between the outer cylindrical wall and the inner tube. The inner tube is formed, in at least a major length thereof, with a plurality of corrugations. An air inlet connection is provided at an inlet end of the annular space downstream of the exhaust tube. The annular space also has an outlet upstream of the exhaust tube adjacent an inlet end thereof and connectable to a burner supplying same with heated combustion air.

Abstract: An improvement in negative pressure radiant tube type fuel burner systems is disclosed wherein a heat recuperator in the form of a concentric conduit arrangement for conveying air from the atmosphere to a burner unit extends inwardly into the exhaust leg of the radiant tube so that combustion air for the burner is diverted along generally parallel oppositely directed coaxial paths into and out of the radiant tube to transfer heat from exhaust gas to intake air. The recuperator is made to be free floating within the radiant tube so as to minimize the chance of structural damage due to thermal expansion and a series of radial pins may be employed in conjunction with the recuperator to support the conduit arrangement, and increase heat transfer to incoming air.

Abstract: The support of the invention permits the thermal expansion of the heating body (1) without having an adverse effect on the heating capacity or on the satisfactory operation of the furnace, by joining the tubular hairpin bends (2, 3) of the heating bodies (1) by means of a link (17), and by suspending a unit from a rest (18) sliding on a support arm (19) rigidly fixed to the wall of the furnace.

Abstract: An improvement in negative pressure radiant tube type fuel burner systems in disclosed wherein a heat recuperator in the form of a U-shaped conduit for conveying air from the atmosphere to a burner unit extends inwardly into the exhaust leg of the radiant tube so that combustion air for the burner is diverted along generally parallel oppositely directed paths into and out of the radiant tube to transfer heat from exhaust gas to intake air. The recuperator is made to be free floating within the radiant tube so as to minimize the chance of structural damage due to thermal expansion and a series of baffles may be employed in conjunction with the recuperator to both increase heat transfer to incoming air and to diminish radiant heat loss from the radiant tube.

Abstract: A broiler for cooking food products has an upper heating unit located in a spaced relationship from the food and a lower heating unit in a close heat transfer relationship with the food. The upper unit is preferably a U-shaped radiant fire tube with a gas-fired power burner mounted at one end as a heat source. Hot flue products exiting the radiant tube are directed to the lower heating unit which is preferably a heat pipe assembly with evaporator and condenser zones for a working fluid. In one form the condenser zone includes a generally flat wall portion with a cooking surface defining a set of upwardly facing grooves. In another form the condenser zone is a series of generally parallel pipes that extend under the food in a horizontal, mutually spaced relationship. A movable rack supports the food and moves it into and out of a cooking relationship with the condenser zone of the heat pipe assembly.

Abstract: A radiation tube with a multibranch heat-radiating housing, one of the branches accommodating a burner comprised of a cylindrical air supply shell having inlet and outlet portions, the shell being disposed axially relative to the heat radiating housing so as to form an annular passageway, the passageway having a crossplate provided with one central and a plurality of circumferential apertures for the passage of air therethrough. The burner is further provided with an annular gas header defined by the inlet portion of said air supply shell and a partition wall interposed between the air supply shell and the heat-radiating housing, said partition wall having openings for uniform distribution of gas flow.

Abstract: A solid circular plate mounted above the existing stirrer in a melt grid spinning apparatus provides a positive hold-up time for melting flake descending from the melt grid to the melt pump beneath the grid.

Abstract: Disclosed are a method and apparatus for clean, low loss melting of aluminum using heat transfer by convection and radiation in separate stages. Heat input to a melter stage is provided by silicon carbide tubes into which gas-fueled burners fire so that the tubes radiate heat to a molten aluminum bath. Combustion products exiting the silicon carbide tubes pass through recuperators, preheating burner combustion air. The combustion products then are piped to a preheater stage and formed into jets of hot gases. The jets are directed into convective contact with solid aluminum stock as the stock is transported along a conveyor, preheating the stock to a temperature of about 1,000.degree. F. The solid stock then is fed to the charge zone of the melter stage and melted by contact with the molten bath.

Abstract: A heating furnace in which radiant tubes are extended widthwise into the furnace so that the products of combustion are discharged into the furnace, whereby intermediate shapes such as slabs which are transported through the furnace are heated to desired rolling temperatures.

Abstract: In order to permit operation with preheating of the combustion-supporting air to 50 or preferably 65 percent or more of the oven temperature, the air is fed to a ceramic burner tube through an annular nozzle directing it in an annular jet along the interior walls of the burner tube. For a burner of low back pressure having no restriction at the mouth of the ceramic burner tube, the ceramic burner tube fits over the end of the outer member of the annular nozzle and some of the combustion product gas, flowing from the oven into the burner structure for countercurrent of the preheating of the air supply, is sucked into the underpressure zone between the annular air jet and the inner wall of the burner tube through a small annular gap where the burner tube fits on the air-supply nozzle.

Abstract: A radiant heating apparatus of the type that has a heating tube (13) with ends (14, 15) opening outside the furnace chamber (12), has first and second regenerator cores (33, 34) in opposite first and second tube ends (14, 15) and first and second fluid fuel burners (37, 38) in the tube (13) at the inner ends of the respective first and second cores (33, 34). A cycling control (30, 299) causes inlet air to be admitted to the first end (14) of the tube (13) while the first burner (37, 38) operates and to be exhausted through the second end (15) of the tube (13), thus heating the second core (34). Thereafter the cycling control (30, 299) causes inlet air to flow through the heated second core (34) while the second fluid fuel burner (37, 38) operates, thus heating the first core (33); and the unit continues to heat the regenerator cores alternately.

Abstract: A furnace is described as having a heat treatment chamber which is provided with banks of radiant heaters to heat a load that is placed within the chamber for heat treatment. The radiant heating of the load is improved by the addition of convection heating which is carried out by a plurality of nozzles that are designed to direct jets or streams of heated gas against the load positioned in the chamber.

Abstract: An improved conveyor assembly is provided for transporting a transparent vitreous substrate along a group of controlled radiative heaters. A plurality of control groups are formed from the radiative heaters and the illumination for the various control groups is isolated so that areas of the conveyor or substrate are illuminated by only a single control group at any one time. Heater control thermocouples are affixed to the radiative heater elements and the output signals from the control thermocouples are calibrated from a calibration thermocouple extending to a position between the control thermocouple and the substrate surface. A wire mesh belt assembly permits illumination of the substrate through the conveyor assembly while supporting the substrate in a manner effective to obtain uniform heating of the substrate.

Abstract: An insulated furnace, method of manufacture and purging operation which includes a plurality of interconnected modular panels of fibrous material forming a furnace chamber, a heat source for the furnace chamber and a furnace shell surrounding the fibrous material panels so as to form a space between the shell and the fibrous material panels and to provide a thermal break of greater than 10.degree. F. such that the furnace can be rapidly heated and water vapor and air can be rapidly purged from the furnace. An insulation panel is formed of at least one block of fibrous material in a molded form which includes mixed fibers and a frame member to which the at least one block of material is secured.

Abstract: An apparatus for the continuous porcelain enameling of sheet ware including the combination, in succession, of a drying zone for the incoming ware either integral or separate, a pre-heating zone for the ware following the drying zone, a heating zone for the ware after the pre-heating zone or zones, in which the porcelain enamel coating is fused onto the surface, and a cooling zone or zones. Burner means are provided for introducing hot combustion gases into a serpentine tube radiant heater which is in the heating zone to heat the ware by means of flameless radiation. After leaving the heating zone, the hot combustion gases are directed into the final pre-heating zone where they transfer some of their heat to the ware passing through that zone. Finally, the combustion gases leaving the pre-heating zone are directed into the drying zone where they transfer heat by convection to remove moisture and slightly pre-heat the ware, whereupon the relatively cool combustion gases are exhausted from the drying zone.

Abstract: An internal plug-in recuperator positioned within the exhaust assembly of a furnace for increasing the efficiency of a combustion furnace system by using less fuel input per heat output than conventional systems. Hot exhaust gases flowing within the exhaust assembly heat ambient air are directed through the recuperator before that air is injected into the burner. Preferably, the recuperator is constructed in a counterflow arrangement with an inner recuperator tube positioned within an outer recuperator tube.

Abstract: A burner housing lodged in a furnace wall comprises a nest of coaxial tubes including an inner gas-supply tube terminating in a burner head, an intermediate air-supply tube extending past that head to form a combustion chamber, and an outer tube defining with the intermediate tube a return duct for combustion gases. The metallic intermediate tube is provided with thermally conductive vanes facilitating the preheating of the entering combustion air by the high-temperature exhaust gases whose residual heat is then utilized to preheat the incoming fuel gas in a heat exchanger laterally connected with the outer tube. An ancillary burner at the opposite end of the inner tube directs a pilot flame toward the burner head.

Abstract: Means and method of operating a tunnel kiln in which green carbon articles are baked in the ware (article) space of a baking zone by heat produced by the combustion of fuel directed to chambers adjacent the zone. The combustion chambers are connected in fluid communication with flues extending lengthwise of the kiln, the flues having a pressure gradient that extends lengthwise of the flues. The method of the invention includes the step of changing the pressure gradient within the flues such that a pressure differential between the combustion chambers and the ware space is effected that causes products of combustion to flow into the ware space from the combustion chambers in amounts sufficient to impede and prevent the deposition of coke formations on the walls of the space without burning the carbon articles.

Abstract: The calciner is an elongated, insulated chamber, in which material is fed to counter-rotating screw conveyors. The material is calcined by heat radiating from a muffle plate interposed between the conveyors and gas-fired burners. This radiant heating, applied evenly to material having a constantly-exposed fresh surface, results in increased production, lower fuel cost per pound of product, and higher quality product.

Abstract: A vacuum aluminum soldering furnace comprising an evacuatable soldering cber having two lateral heating zones. The soldering chamber has a middle heating zone arranged parallel to the lateral heating zones and the heating element of the middle heating zone is preferably arranged removable from the soldering chamber.