Abstract: A dryer or oven of the type utilizing radiant burners having a heating chamber extending therethrough with opposed sides in which radiant burner units are arranged in spaced rows with enclosure panels therebetween. The burner units face opposed panels and the panels are formed with radiantly refelective surfaces for re-radiation of heat from the burner units into the heating chamber. In one form, a dryer is formed with T-shaped modules, each having narrow vertical sections and top cross-sections for joining in face-to-face relation to adjacent units, with exterior access spaces between the vertical sections and with the burner units having back sides exteriorly exposed in the spaces for convenient access. In another form, an oven is formed with burner units and enclosure panels extending in a longitudinal horizontal heating chamber that is open along its top for passage therethrough of articles suspended from a conveyor.

Abstract: A copying machine includes a sheet heating device for heating a sheet to fix a developed image thereon. The sheet heating device includes a heater unit extending transversely to and substantially fully across the sheet feed path, and an air blower for supplying air to the heater unit substantially fully across the sheet feed path and along a surface of the sheet in a direction opposite to the direction in which the sheet is fed along the sheet feed path. The sheet heating device also includes a cover covering the heater unit and the air blower and having an inlet slot and an outlet slot, and a guide plate disposed underneath the cover. The sheet heating device further includes a plurality of fixed or angularly movable air flow guide vanes for guiding an air flow from the cross-flow fan toward the heater unit. The air flow guide vanes are disposed between the heater unit and the cross-flow fan and spaced at intervals along the heater unit.

Abstract: A heating apparatus comprising a heating chamber the inside of which is heated to a fixed temperature and which is provided with an entrance and an exit through which articles to be heated are taken in and out of the heating chamber, a support on which the articles are supported inside and outside of the heating chamber, a conveyer which moves vertically and horizontally so that the top surface of the conveyer is above and below the top surface of the conveyer is above and below the top surface of the support and that the conveyer reciprocates in the direction in which the articles are conveyed, and a pair of doors for opening and closing the entrance and exit of the heating chamber, whereby the articles are successively moved over a fixed distance by the conveyer toward the heating chamber, thereby providing a heating apparatus with a simple structure in which articles such as semiconductor devices are conveyed to the heating chamber without vibration and then properly heated in the heating chamber.

Abstract: Printed circuit boards, assemblies and the like are heated uniformly from edge to edge or to a desired lateral temperature profile while being conveyed through a heating area. The conveying systems reliably conveys circuit boards and the like through the heating area without dropping them. A rail heater is provided to heat rails supporting conveyors having pins to hold circuit boards and the like. A control for the rail heaters controls the temperature of the rails so the circuit boards are positively supported on the conveyors and have a uniform temperature profile or desired temperature profile from edge to edge.

Abstract: Printed circuit boards, assemblies and the like are heated uniformly from edge to edge or to a desired lateral temperature profile while being conveyed through a heating area. The conveying systems reliably conveys circuit boards and the like through the heating area without dropping them. A rail heater is provided to heat rails supporting conveyors having pins to hold circuit boards and the like. A control for the rail heaters controls the temperature of the rails so the circuit boards are positively supported on the conveyors and have a uniform temperature profile or desired temperature profile from edge to edge.

Abstract: The apparatus comprises a steel belt (5) extending according to an endless strap around two guide rollers (3, 4) driven in rotation according to horizontal axes. The upper part of the belt (5) defines a first going stretch (5a) onto which the product (6) in progress of working is laid, said product being transported due to the movement communicated to the belt as a result of the rotation of said guide rollers. Water is sprayed against the underneath surface of the first belt stretch for cooling the product through a heat exchange with the belt itself. The apparatus further comprises a heat exchange roller (14) rotatably supported according to the horizontal axis and arranged so that it comes in contact with the product (6) located on the first belt stretch (5a). Water circulation takes place within the heat exchange roller (14) and an additional cooling action is therefore accomplished on said product (6).

Abstract: A heating furnace comprises a horizontal body portion, a source of heat located at an intermediate portion of the body portion for forming hot gas which circulates in the body portion by natural convection, a gas discharge port formed in the wall of the body portion, a gas collecting hood connected to the lower end of an exhaust cylinder, and a horizontal conveyor for conveying an article to be heated through the furnace. The opposite ends of the body portion act as the inlet and outlet ports as well as gas discharge ports. In one embodiment, upper half portions of the inlet and outlet ports are covered by shielding plates. In another embodiment the opposite ends of the body portion are inclined downwardly to form the inlet and outlet ports near or below the bottom surface of the furnace. In still another modification, air curtains are formed at the inlet and outlet ports.

Abstract: In a printing sheet conveying device in which a sheet bearing a toner image is passed through a heating roll and a pressure roll, and which has means for changing the right and left contact pressures of these rolls to correct the meandering movement of the sheet when conveyance of the sheet is started; in which when conveyance of the sheet is started, the contact pressure of the rolls is made higher on one of the right and left sides than on the other side, and in a predetermined period of time the contact pressures on both sides are made equal to each other.

Abstract: A forced jet convection oven is utilized to practice a vacuum bagging process for the production of thermoplastic composite laminates containing reinforcing fiber. The oven comprises a support suitable for supporting a panel wherein said support means is positioned in the oven with the upper surface of the support means being spaced apart from the oven ceiling to define a panel-receiving chamber between the upper surface of the support means and the oven ceiling, a first manifold means having a first multiplicity of outlets directed toward the upper surface of the support means wherein said first manifold means is positioned between the upper surface of the support means and the oven ceiling; and a second manifold means having a second multiplicity of outlets directed toward the upper surface of the support means wherein said second manifold means is positioned between the upper surface of the support means and the oven floor.

Abstract: A multimode thermal treatment system includes a series of particle treatment zones. Perforate conveyer structure for supporting the particulate product to be thermally treated is disposed for movement through the series of treatment zones. Each treatment zone includes first (upper) distribution plenum structure disposed above the treatment zone and an array of nozzle tubes extending downwardly from the upper distribution plenum into the treatment zone to flow conditioned gas with substantial velocity into the treatment zone for thermal treatment of particulate material being transported by the conveyer structure through the treatment zone; and a second (lower) distribution plenum disposed below the treatment zone for pressurizing the region below the treatment zone and flowing conditioned gas upward through the conveyer structure and the particulate material on the conveyer.

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: A high velocity web dryer which has a series of upper and lower air bars for floatingly suspending a running web as the web moves through the dryer. A hot air supplying system provides hot air to the bars for drying the web. The system includes a gas fired burner and a source of combustion air for the burner. A valve control is provided for controlling the admission of combustion air to the gas fired burner, and includes a movable valve for controllably admitting combustion air to the burner. The said valve control includes an initial air admitting valve for providing initial air through the valve control prior to partial opening of the valve control, to thereby provide a relatively smooth and excessive surge-free supply of air to the burner, whereby a stable air supply system in provided without oxygen starvation and without blowing out a flame of the burner.

Abstract: Apparatus and method for storing and subsequently dispensing environmentally sensitive material into a manufacturing process is disclosed. The material is stored in an environmentally controlled chamber and conditioned prior to being dispensed into the manufacturing process.

Abstract: A drier for a web of material in particular for a offset printing machine, consisting of an housing with an inlet slot and an outlet slot for the web of material. The housing is provided with air nozzles which are fed via one or more fans with the atmosphere in the housing. The housing also have at least one heating appliance provided with a combustion unit for treating the atmosphere inside the housing. The interior of the housing is divided by a partition into a heating section and an evaporating section. The heating appliance is provided with an incinerating portion and part of the combustion gases is via an opening discharged to the heating section, while the remaining combustion gases are discharged into the outside air, and the atmosphere of the evaporating section is used as combustion air for the burner of the combustion unit.

Abstract: A furnace for firing an enamel-insulated wire comprising a principal cham, an auxiliary unit for withdrawing a first stream of air and solvent vapors from this principal chamber for effecting combustion of the vapors themselves. A part of a second stream leaving the auxiliary unit is mixed with a volume of air at ambient temperature and passed to the principal chamber; another part is sent to a heat exchanger in which it gives up part of its thermal energy to a second volume of air at ambient temperature which is heated and introduced into the principal chamber.

Abstract: A method and an apparatus for treating materials in a combustor are disclosed. A pair of axially aligned slide gates extend longitudinally through the combustion chamber of the combustor. The innermost ends of the gates abut when the gates are closed, with the gates being openable by moving them axially apart to define a treatment aperture. Movement of the two gates permits the aperture to be positioned at a desired location in the combustion chamber, while movement of one gate with respect to the other adjust the width of the aperture.

Abstract: A rotating-drum heat treatment apparatus for carrying out cooling or heating of a material to a desired temperature. The apparatus includes two drums arranged in a casing adjacent to each other for continuously cooling or heating the material to be heat-treated, to thereby increase a time required for the heat treatment of the material.

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: Continuous ovens are known for soldering electronic components on circuit boards, with a conveyor belt having supports for the circuit boards, and having infrared radiators disposed in a spaced-apart relationship along the conveyor belt above and/or below the plane of belt movement, which are associated with at least one preheating zone and, following this zone in the direction of movement of the belt, with a soldering zone. To develop a continuous oven such that the temperatures between large and small components to be soldered on circuit board will be nearer one another in the soldering zone than in conventional ovens, a cooling zone is disposed between the preheating zone and the soldering zone, in which a forced cooling is performed with a gaseous coolant which is driven by a blower through nozzles disposed in the cooling zone substantially perpendicularly to the plane of the conveyor belt.

Abstract: An apparatus for the heat treatment of a continuously moved wire which loops in several turns round a drum arranged in a heat-treatment zone, has at least one tension roller which is assigned to the drum and around which each wire turn is looped in series with the drum, and the axle of which is displaceable in parallel and/or pivotable relative to the axle of the drum counter to the effect of a limited tension force exerted by a tensioning device, thereby preventing the wire from breaking in the event of an interruption in operation and the stopping of the drum.

Abstract: A compact web dryer oven (A) is disclosed which is heat efficient, may be open for convenient cleaning, and raises automatically under the effects of an explosion to relieve pressure and reduce damage to the oven interior. The oven includes a lower housing (B) and an upper housing (C) which are essentially identical. Each housing includes an air distribution system having a short path and recycle time which includes a hot air discharge blower (H), an air reducing plenum (I), and a redirecting chamber (J) which directs the air in a vertical direction. An elongated air diffuser manifold (K) extends the length of the housing and includes a radial arrangement of pipes (71) and radial air openings (72) which distribute the air (45) in equal parts across the width of web (W). Lower and upper hot air registers (E,F) receive the proportioned air flow. The air registers include spaced tubular members (22) transverse to the air diffuser manifold having an air divider nozzle (G) positioned between each member.

Abstract: In a high-temperature heating furnace, its central longitudinal passage in which articles to be heated are placed, and its inner support which makes a space between its inner surface and the above-mentioned passage for accommodating heaters therein and which makes also another space between its outer surface and a furnace shell for filling insulators therein, are both installed in the furnace by assembling a plurality of thin plates made of carbon fiber reinforced graphite or carbon compounds to cuboids which are coaxial to each other and have rectangular cross sections.

Abstract: This invention relates to a method of using a liquid or powder varnishing furnace utilizing near-ultrared bulbs to form high temperature regions and low temperature regions which are alternatively disposed and spaced apart by a fixed distance to heat a cleaned and painted workpiece, whereby the workpiece is dried rapidly and paint sprayed onto the workpiece firmly adheres thereto.

Abstract: An apparatus and method are presented for removing filler from electrical cords during manufacture. The electrical cord is stripped of its outer jacket to expose the filler and conductors and thereafter positioned within a nozzle where the stripped end is subjected to microprocessor controlled heated and unheated air pulses to degradate and remove the filler along the stripped end portion prior to attaching the cord conductors to electrical appliances or the like.

Abstract: A furnace for firing electrically conductive wires clad with an insulating lastics resin, comprising a principal chamber defining a first portion in which evaporation of solvents from the resin takes place and a second portion in which this resin is polymerized and cross linked, and a diffuser element provided with separator means operable to divide the gas stream into a plurality of partial streams and means for distribution and introduction of these partial streams into a peripheral zone of the first portion in a direction substantially parallel to the lateral surface of the first portion itself.

Abstract: A preheater assembly for softening a selected portion of plastic stock material prior to severing and edge sealing is disclosed. The preheater assembly includes a pair of opposed preheaters, each having a heater tip connected to a source of heated air. The air flows through the tip to maintain it at a preselected temperature. The preheaters are mounted on opposite sides of the stock material for motion toward the material to engage it on opposite sides to heat and soften it, and away from the material to release it. Clamp elements engage the stock material during the heating and softening process.

Abstract: Apparatus for the heat treatment of a length of continuously moving material in a plurality of treatment zones contains a fan to provide a stream of circulating air. The outer wall of the machine and fan housing is provided with an opening which can be closed by a closure device, through which the interior of the fan housing and the nozzle casing are accessible.

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: An air texturing system for partially oriented yarn in which a draw block of aluminum or other suitable material is employed to provide two stages of drawing for the yarn to be textured. The draw block has an inlet offset from the outlet to provide for one stage of drawing between the inlet and outlet of the draw block.

Abstract: The invention relates to a continuous material heating oven ideally suited for sterilizing and depyrogenating materials for introduction to a sterile environment. The oven includes a cool air supply means which is self-deprogenating eliminating the need for manual sterilization. A volumetric airflow control means is included with the cool air supply means for substantially linearly cooling materials to reduce breakage. Control means is provided by the system for maintaining the sterile environment at a greater positive pressure than its adjacent environments to protect the sterile environment from contamination.

Abstract: A method for heating stock comprises feeding stock 9 to be heated into a heating chamber 1, causing heating gas to enter the heating chamber 1 to heat the stock 9 and leave the heating chamber 1 after heating the stock 9 and then removing the stock 9 from the heating chamber 1 on completion of heating, the heating gas being allowed to enter the heating chamber 1 by way of a plenum chamber 2,3 which communicates with the heating chamber 1. The heating gas may be supplied by a regenerative burner 4,5 as fuel combustion products. Where there are two such burners 4,5 one may be firing while the other is flueing.

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 method and apparatus for treating sludge from a paint spray booth operation. The sludge from the spray booth is deposited onto a porous belt of a conveyor system to allow the water to pass through the belt where it is collected for discharge from the apparatus. The remaining residue is passed over a vacuum device positioned beneath the belt and is then carried by the belt through an oven comprising a series of infrared thermal reactors arranged in serial fashion over the belt. The sludge is passed continuously beneath the infrared reactors and is dried thereby so that the sludge leaving the apparatus is in a dried particulate form which may be readily disposed of and/or solid. Convection air is recirculated through the apparatus to preheat the incoming sludge, remove smoke and other contaminants from the oven, and provide the desired pressure condition within the oven to optimize the efficiency of the thermal reactors.

Abstract: An improved full color electrophotographic print engine using flexible belts to carry a photosensitive electrostatic image developer and a transfer belt for building up composite developed images. Each belt, and an optical scanner, are driven by mechanically independent motors which are synchronized by an electronic digital controller implementing precise servos. The use of the flexible belts allows the machine to be relatively inexpensive, very small compared to previous full color print engines, and yet maintain precise registration of color composite images. An improved fuser mechanism with increased dwell time at constant machine speed is also shown. The fuser includes a pair of spaced-apart rollers, both of which urge a sheet of image receptor against the heated roller over a predetermined angular portion of the roller. The machine is specifically designed to be used interchangeably with an optical bench source as a copier or with a laser bench as a laser printer.

Abstract: A method and apparatus for heating fibers reinforced thermoplastic sheets is disclosed. The apparatus involves use of gas heating ovens adapted to allow several layers of material to be heated continuously, with the conveyors stacked are above the other. Stacking of the heated product can be provided at the oven exit. Provisions for cleaning and diffusing the gases over the work piece are also described.

Abstract: A low velocity oven seal for use with an elongated oven complex of the type in which articles to be processed are moved longitudinally through the oven. The seal includes an air seal compartment adapted to be aligned with the entry end of the oven complex to form a prefix to the oven complex. In one form of the invention, a blower assembly is mounted on the roof of the air seal compartment adjacent the exit end of the comparment and functions to withdrawn air from the upper region of the air seal compartment adjacent the exit end thereof for delivery to a pair of plenum chambers disposed at either side of the air seal compartment. The air delivered to the plenum chamber is introduced into the lower region of the air seal compartment generally below the path of the articles being processed within the oven complex and this air in turn moves upwardly and toward the exit of the air seal compartment where it is received by the inlet to the blower assembly to complete the air cycle.

Abstract: A method and apparatus for heating fibers reinforced thermoplastic sheets is disclosed. The apparatus involves use of gas heating ovens adapted to allow several layers of material to be heated continuously, with the conveyors stacked are above the other. Stacking of the heated product can be provided at the oven exit. Provisions for cleaning and diffusing the gases over the work piece are also described.

Abstract: An oven includes a plurality of pairs of upper and lower spaced non-focused infrared heater panels. Product is conveyed between these panels to effect solder reflow. To increase heat transfer and to achieve temperature uniformity, air is forced through equally spaced holes drilled in the insulating block of one or more upper heating panels. To define an equal flow through these holes, a valve is placed below the air intake opening to define an annular opening between the panel casing and the valve. The valve has openings having an area which is matched to the annular area between the casing and the valve.

Abstract: In the modular kiln, which is designed for the firing of ceramic tiles etc., one has a series of single treatment zones (16) arranged in a continuous succession and interconnected by a conveyor (6); heat exchange is brought about by radiation between special surfaces built into the various zones of the kiln, and the material being fired.

Abstract: A process and apparatus for removing volatile contaminants from scrap metal is disclosed. The process is carried out in a furnace maintained at a relatively constant temperature and having a first zone in which volatiles contained on the surface of the metal are vaporized and a second zone in which carbon contained on the surface of the metal is pyrolyzed. The furnace also has a conveyor for transporting metal therethrough at a specific speed to ensure complete vaporization and pyrolysis of the contaminants. The process includes the steps of sufficiently vaporizing the volatiles without oxidizing the metal, the vaporizing producing fumes containing unburned hydrocarbons. The hydrocarbon fumes are then burned to produce hot gas which is recirculated to the furnace. The hot gas contacts the incoming metal and vaporizes the volatiles contained thereon.

Abstract: A method and apparatus for heating fibers reinforced thermoplastic sheets is disclosed. The apparatus involves use of gas heating ovens adapted to allow several layers of material to be heated continuously, with the conveyors stacked are above the other. Stacking of the heated product can be provided at the oven exit. Provisions for cleaning and diffusing the gases over the work piece are also described.

Abstract: A continuous heat treating furnace is equipped with an automatic flow control system and contains a high-temperture treating zone internally provided with a plurality of burners, a pre-heating zone connectively disposed at one end of the high-temperature treating zone and a cooling zone connectively disposed at its other end, the pre-heating and cooling zones being partitioned into a plurality of compartments each provided on its ceiling portion with a convection fan.

Abstract: Apparatus for melting by vapor-phase treatment a solder applied to an object. The liquid serving for vapor production, which is situated in a vessel, is heated by electrical heating means which are disposed exclusively outside of the vessel and are completely enveloped by a liquid heat-carrying medium. The vessel floor is provided with projections to increase the thermal transfer. A tubing coil is furthermore disposed in the heat-carrying medium for rapid cooling thereof.

Abstract: A method for producing carbon fibers in a vertical carbonizing furnace and an apparatus for producing carbon fibers using such a method are disclosed. The furnace includes a heating chamber for carbonizing fibers, the furnace including,(i) a fiber inlet at the upper end of the chamber(ii) an air tight sealed fiber outlet at the lower end of the furnace,(iii) an inert gas inlet provided on the wall of the chamber and above the fiber outlet,(iv) at least one inert gas injection portion, formed on the wall of the chamber, each capable of forming a curtain of inert gas across the heating chamber, each injection portion being provided between the gas inlet and the fiber inlet,(v) at least one outlet each being provided below each inert gas injection portion, and(vi) a heating member capable of controlling the temperature in the heating chamber in such a manner that the temperature gradually increases from the upper end toward a lower end of the heating chamber.

Abstract: A wire coating oven (2) is disclosed which includes a wire cooling apparatus (1) for cooling a wire (3) passing therethrough, while minimizing gaseous emissions. The cooling apparatus includes a wire cooling passage (10) having a wire entrance end (13) adjacent the oven and a wire exit end open to the atmosphere, with the wire cooling passage defined by a first wall (11) which surrounds the wire passing therethrough. A hot gas passage (15) is defined by a spacing between the first wall and a second wall (14) disposed adjacent thereto with hot gas entering the passage at about the wire exit end and exiting at the oven end. The first wall includes an outwardly tapered surface (19) near the wire entrance end for forming a venturi with the second wall, whereby a hot gas passing therebetween creates a negative pressure within the wire passage, drawing cool air (20) into the wire passage, cooling the wire and drawing any vaporous emissions into the oven.

Abstract: The invention resides in the temperature control of the oven of a gas chromatograph. A variable speed fan circulates air within the oven. Vents in the oven wall open automatically in response to pressure imbalances between the ambient atmosphere and the oven interior. Temperature is controlled by regulated exchanges of ambient and oven air produced by variations in fan speed.

Abstract: The process comprises creating a screen of non-reactive or inert gas at least at one of the two ends of the heat treating zone or cooling zone of a furnace, the screen being substantially homogeneous and laminar throughout its height. The use of this process permits, on the one hand, a reduction in the flows of gas necessary for the heat treating and, on the other hand, the division of the heat treating furnace into precise zones. The invention is particularly applicable to heat treating furnaces.

Abstract: A high temperature fan plug for a jet heat recuperator includes inner and outer face plates spaced apart by tubular spacers extending between the plates to form a heat insulative cavity. A fastener bolt extends from one face plate through a tubular spacer and projects from the other face plate. A spring with washers at opposite ends thereof is compressed by nut members on the end of the bolt which projects from the face plate for clamping the outer and inner face plates against the spacers. A hub structure carried by the inner and outer face plates receives a seal. The face plate exposed to high temperatures in the recuperator extends between spaced apart rings that are secured to a rim that is in turn carried by the other of the face plates. The rings slidably engage the outer peripheral portion of the face plate exposed to the high temperature environment.

Abstract: A continuous annealing furnace for a strip which is provided with a first treating furnace of horizontal type including at least a heating zone and a soaking zone, and a second treating furnace of vertical type disposed adjacent to the first treating furnace. The first treating furnace further includes a floating type transporting means which is composed of plural stages of floating type supporting devices for supporting the strip to be treated on them in a floating state, and a plurality of direction changing devices for transporting the strip from an upper stage towards a lower stage of the supporting devices, and the second treating furnace includes a plurality of rolls for transporting the material in a zigzag manner on vertically arranged multi-row passage.

Abstract: An indirect-fired, infrared drying oven for articles of manufacture which have been through a coating process. Tubular radiators are mounted within the enclosure to produce infrared radiation which impinges upon the coated articles. The tubular radiator operates at a sub-ambient interior pressure and is vented near the burner to directly inspirate fumes from the interior of the oven as they are given off by the drying articles. Temperatures in the radiator are sufficient to incinerate the fumes as they travel along the length of the tubular radiator. A heat exchanger is utilized near the exhaust end of the radiator to recover waste heat and return this heat to the oven enclosure, thus balancing air flow within the enclosure and maintaining a neutral pressure condition.