Abstract: The invention is a highly portable ground defrosting device that has a manually portable housing which includes a sidewall, a roof connected to the side wall and an open bottom. The side wall and roof each have a coefficient of thermal conductivity of less than about 0.6 BTU-in/hr-ft.sup.2 -.degree. F. at 400.degree. F., and the side wall and roof together define an enclosed heating chamber. At least one port extends through the side wall for receiving a removable burner which substantially occupies and is exhausted through the one port so that the chamber is substantially airtight as the apparatus rests on the ground.

Abstract: A burner device of regenerative and alternate combustion type including a pair of burners and a regenerative bed, which permits flow passage changeover to be taken selectively between the pair of burners, via the regenerative bed, by four-way and three-way valves which are simultaneously operated by one actuator. Preferably, both two valves are connected coaxially together. The four-way and three-way valves have a same angle of rotation for executing their respective flow passage changeover actions, but they each have its own inoperative area defined differently from each other to produce a difference in timing for supply of fluid to one of the two burners, thereby providing a lead time for prior supply of air and a delay time for delaying supply of fuel to facilitate ignition in one of the burners during the alternate combustion operation.

Abstract: A gas radiant tube heater and method of operating the heater. The heater has a housing and a radiant tube mounted within the housing. The heater further has a modular control box mounted within the housing in which serviceable parts can be easily removed as a unit and replaced. The housing and control box are sealed against the elements for outdoor as well as indoor use. The control box is divided into two chambers, with the inlet air flowing from a first chamber into a second chamber. The first chamber is subjected to a vacuum pressure, in which the heat sensitive equipment is mounted, and the second chamber is subjected to a positive pressure, in which the combustible gas and air mix prior to combustion. The heater further has a pressure switch to shut off the gas supply if the air flow through the heater is blocked, and a flame sensor to shut off the gas supply if the ignition element fails to ignite the air/gas mixture.

Abstract: A burner assembly combines air and fuel to produce a burn firing into a downstream tube. The assembly includes a funnel formed to include an inlet, an outlet, and an air and fuel mixing region therebetween. The funnel also includes a cylindrical intake end at the inlet and a conical side wall mating with the cylindrical intake end and converging from the cylindrical intake end toward the outlet to fire a burn initiated in the mixing region into a tube coupled to the outlet of the funnel. The assembly also includes a system for supplying a gaseous fuel to the mixing region in the funnel and a system for introducing combustion air into the mixing region through the inlet of the funnel. The combustion air mixes with the gaseous fuel in the mixing region to produce a combustible mixture.

Abstract: An easily repairable, high efficiency, durable, compact heat exchanger having a modular heat exchanger tube may be provided. The modular heat exchanger tube may be easily disassembled so that any of its modular component tubes (such as its combustion area tube) may be easily removed for repair or replacement. Internal alignment and sealing sleeves may be provided for the adjacent modular component tubes of the heat exchanger tube. The internal sleeves may automatically and permanently increase their sealing power due the automatic and permanent expansion they undergo when they are stress relieved by being heated for the first time by the combustion gasses within the heat exchanger tube. Stress cracking of the heat exchanger tube may be reduced by supporting the heat exchanger tube so that it may move freely as it heats up (expands) and cools down (contracts) during the normal thermal operating cycles of the heat exchanger.

Abstract: A burner assembly (10) for a radiant heater of the infrared type. The burner assembly includes a burner tube (12), a generally cylindrical mixing cup assembly (14), means (16) for mounting the cup assembly within the burner tube, means (18) for introducing air into the upstream end of the burner tube, and means (20) for introducing combustible gas into the burner cup, the gas and air being thoroughly mixed together in the burner cup. The cup assembly includes a generally cylindrical mixer tube (32), and passageway means at the downstream end, the passageway means including a ceramic block (34) and a metallic grid (36) in contact with the downstream face of the ceramic block. The ceramic block has a plurality of relatively small orifices (34.1) which extend through the block. The metallic grid (36) has a plurality of relatively small apertures (36.3) and a large central aperture (36.4).

Abstract: A burner suitable for heating a furnace chamber of an industrial furnace which is equipped with a recuperative preheater for combustion air has a combustion chamber at one end and a feed-through cap at the other end which is accessible outside of a furnace in which the burner is installed. The tubular recuperative preheater is of the coaxial countercurrent flow configuration extending between the combustion chamber and an annular outflow collector cap. A coaxial fuel pipe is centered in the burner extending to the combustion chamber. Overheating of the burner cap is prevented by means of a spacer sleeve of small heat conductivity interposed between the preheater and the burner cap. This permits the valves to be seated in the burner cap without risk of thermal damage. For protection of personnel against contact with hot surfaces, a perforated metal shield is provided between the burner cap and the outflow cap of the recuperator, essentially covering all the portions of the burner outside a furnace wall.

Abstract: A self contained catalytic heating device within which a fuel/oxidizer mixture and combustion products are held out of physical contact with a heated medium, allowing the temperature of the catalytic material to be maintained at a level that is independent of the temperature at the surface in contact with the heated medium; materials and geometric dimensions can be chosen to achieve required temperatures for catalytically coated surfaces and heating surfaces, for example in a tubular construction.

Abstract: A jacketed jet radiant heater for an industrial process furnace as a frame tube composed of axially aligned pipe pieces abutted on one another that are held together by clasps on the outside of the flame tube that have studs which protrude into holes in adjacent pipe pieces and have a head portion which serves to center the flame tube within the jacket tube. The clasps make it possible to provide exhaust gas releasing slots between some of the pipe pieces of the flame tube and thereby avoiding local overheating of the jacket tube.

Abstract: A burner device of regenerative and alternate combustion type including a pair of burners and a regenerative bed, which permits flow passage changeover to be taken selectively between the pair of burners, via the regenerative bed, by four-way and three-way valves which are simultaneously operated by one actuator. Preferably, both two valves are connected coaxially together.The four-way and three-way valves have a same angle of rotation for executing their respective flow passage changeover actions, but they each have its own inoperative area defined differently from each other to produce a difference in timing for supply of fluid to one of the two burners, thereby providing a lead time for prior supply of air and a delay time for delaying supply of fuel to facilitate ignition in one of the burners during the alternate combustion operation.

Abstract: This invention is directed to a heat recovery type combustion apparatus which has a regeverative member of ceramic material attached to the lateral wall of the main body of the combustion apparatus, a rotary duct set in place and adapted to communicate with the regeverative member, an air conduit for allowing flow of combustion air and an exhaust gas conduit for allowing flow of exhaust gas arising from combustion of fuel in the combustion apparatus both formed in the interior of the rotary duct, and rotary means adapted to rotate the rotary duct and enable the combustion air to be heated with the exhaust gas through the medium of the regeverative member.

Abstract: A radiant heating system for a greenhouse utilizing radiator tubing formed from substantially gas impermeable plastic material. The system includes a radiator tube disposed overhead and formed from light transmitting material so that sunlight projecting into the greenhouse will be substantially transmitted to the plants grown thereunder and a second radiator tube disposed proximate the greenhouse floor and formed of similar plastic material. The radiated tubes are interconnected at one of their ends and a burner communicates through a manifold connected to the other ends of the radiator tubes to transmit a heated effluent through the tubes. Valve means and exhaust means are associated with the manifold.

Abstract: A burner head for a recuperative radiant tube burner system is constructed so as to effect clean burning of a gaseous fuel such as butane having a relatively high heat value. The burner head includes a sleeve having a frustoconical section formed with combustion air ports which cause combustion air to spin and mix thoroughly with butane discharged from a gas nozzle having a discharge orifice located downstream of certain ones of the combustion air ports.

Abstract: A radiant tube heater is provided for a gas fired burner which fires heated products of combustion into an inner longitudinally-extending tube which is concentrically pinned to an outer longitudinally-extending tube which in turn is concentrically mounted within a heat transfer, tube which radiates heat to work. The outer and inner transfer tubes have closed axial ends opposite the burner and the inner tube is radially spaced closely adjacent the outer tube to define an annular heat transfer passage therebetween. A specific hole size pattern in the inner and outer tubes in combination with the radial distance of the heat transfer passage insure long path gas flow lengths which promote laminar flow and even heat distribution along the length thereof thus producing a radiant tube which radiates heat uniformly from the heat transfer tube to the work along its length.

Abstract: A radiant heating system for a greenhouse utilizing radiator tubing formed from substantially gas impermeable plastic material. The system includes a radiator tube disposed overhead and formed from light transmitting material so that sunlight projecting into the greenhouse will be substantially transmitted to the plants grown thereunder and a second radiator tube disposed proximate the greenhouse floor and formed of similar plastic material. The radiated tubes are interconnected at one of their ends and a burner communicates through a manifold connected to the other ends of the radiator tubes to transmit a heated effluent through the tubes. Valve means and exhaust means are associated with the manifold.

Abstract: A convection oven comprises a heating compartment, a burner for effecting combustion of gas, a heat exchanger for conducting therethrough the products of combustion of gas initiated at the burner, first and second blowers for blowing air past the heat exchanger and into the heating compartment for heating the compartment, upper and lower blowers each having an inlet through which air is drawn into the blowers from a common side of the heating compartment for recirculation past the heat exchanger, and the heat exchanger having first and second outlets for the combustion products respectively disposed in front of the inlets of the upper and lower blowers. Each outlet is located to direct the combustion products towards a lower region of the inlet of the respective blower.

Abstract: A stream of process gas is indirectly heated in an elongated reaction chamber (1) with a longitudinal axis, a first end (12) and a second end (13) and defined by an outside shell (2) and a thermally conductive inner wall (4). The inner wall defines at least one recess or cavity (3) which extends substantially between the first and second end of the chamber and parallel to the longitudinal axis thereof. A process feed line (6) and a product-gas discharge line (7) are provided at opposite ends (12, 13) of the chamber. A heat conductive and heat resistant barrier (8) which defines an interior space extends coaxially with the recess or cavity (3) substantially along the entire length of the inner wall (4) and forms an annular space (9) therewith. A hot flue gas feed line (10) and a flue gas discharge line (11) is provided at one end (13) of the chamber.

Abstract: A device at a heat treatment oven of the type using a combination of radiation heat and convection heat, and where in connection to the oven chamber are provided means (4, 19) arranged to circulate the oven atmosphere through the oven chamber and a channel (20, 21) situated outside the oven chamber and back to the oven chamber, whereby the device incorporates a gas burner (7) arranged at combustion to emit its flame in a direction, which at least partly touches or coincides with the circulation channel (20, 21) for the oven atmosphere, and where the gas burner (7) is arranged to direct its flame into a vessel (22), provided in the circulation channel (20, 21) for the circulating atmosphere.

Abstract: A single ended radiant tube for furnace heating has four concentric tubes (10, 12, 14, 16). Fuel gas is fed through tube (16) and combustion air through the space between tubes (12, 14). Flame and combustion products flow first in the same direction as the gas and air and then reverse at the end of tube (12) to flow in the opposite direction between that and tube (10). The combustion air is caused to flow in a helical pattern by the provision of helix (36) so as to provide an extended flow path for better heat transfer.

Abstract: A gas-fired heater, in particular of the type having radiant bodies (6) to be heated by gas flames, in which fuel gas and combustion air are supplied under pressure to at least one burner nozzle (19, 10) in a proportion ensuring complete combustion, and further comprising an air chamber (9) in association with the or each burner (20), and the chamber having an outlet terminating in the ambient space of sufficient dimensions to offer no essential resistance to air flowing out into the ambient. A venturi (10) extends from the chamber (9) into the burner (20). A gas supply nozzle (18) is arranged coaxially in front of the throat of the venturi (19) within the chamber (9). Means (3, 7, 8) are provided for supplying air to the chamber (9) in a quantity slightly in excess of that needed for complete combustion at maximum capacity of the burner (20).

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 liquid fuel combustion type infrared ray irradiating apparatus includes a base having a generally rectangular-shaped framework, each corner of which is provided with a wheel, a fuel tank fixed to the base, and a pump disposed on the base and adapted to pump fuel from the fuel tank. A combustion chamber is connected to a burner which receives fuel from the pump for combustion. An irradiation pipe is connected to the combustion chamber for guiding combustion gas from the combustion chamber into an upper chimney, receiving heat from the combustion gas, and irradiating infrared rays. Reflecting plates are disposed to forwardly reflect rearwardly directed radiant heat which has been radiated from the irradiation pipe.

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: A radiant type heater for use in a heating furnace has inner and outer concentric tubes. The tubes have a structure in which silicon carbide particles are joined to each other by a sintering aid such as an aluminum compound sintering aid or a boron compound sintering aid.

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: A post-mix burner having electrical ignition means is particularly adapted for use with radiant tube furnaces. The burner provides two concentric tubes which define a central passage and an annular passage around the central passage. Fuel is introduced into the central passage and primary air through the annular passage. Mixing of the primary air and fuel commences at and near the end of the inner tube. The ignition system provides a spark gap in axial alignment with the end of the inner tube where the mixing of the primary air and fuel commences. The main combustion air is introduced into the burner through an annular pasage surrounding the aforementioned passages. When combustion having substantial length is desired, the fuel and air are introduced into the burner as laminar flow with each component having the same velocity.

Abstract: A hanger for use in a low intensity radiant energy heating system. The hanger is used both for supporting the emitter tube/reflector assembly and as an air dam to prevent convection currents from flowing along the emitter tube due to temperature changes.

Abstract: The apparatus for heating and generating infrared rays has a heating apparatus for indirectly heating a heat medium such as air and water, by a combustion heat and a radiator, wherein a branch combustion gas passage is provided for a combustion gas passage through which the combustion gas in said heating apparatus flows at temperatures of 400.degree. C. or more and 800.degree. C. or less, and said branch combustion gas passage and said radiator are connected.

Abstract: A heating appliance particularly for a drier of a web of material comprising a combustion unit having a burner and a combustion chamber. The combustion chamber consists of an elongated first section extending away from the burner and merging into a second portion via a bend of 180.degree. said two portions defining an U-shaped path for the combustion gases and being approximately of equal lengths. The combustion chamber also being provided with one or more discharge openings for discharging part of the combustion gases, said opening(s) being controllable by means of a valve.

Abstract: An improved immersion tube heater means is disclosed for uniformly and reliably heating oils to a temperature below the oil's critical physical breakdown temperature so as to avoid damage to the oil and coating the tube with damaged oil byproducts.

Abstract: A catalytic combustion device has a fuel supply means communicated with a fuel supply source, an air supply passage communicated with an air supply source, a premixing chamber for mixing together fuel supplied from the fuel supply means and combustion air supplied from the air supply passage to form a fuel-air mixture, a catalyst installed in a combustion chamber to cause oxidation reaction of the fuel-air mixture supplied thereto, thereby effecting catalytic combustion, and an exhaust passage for discharging combustion gas from the catalyst in the combustion chamber.

Abstract: A gas convection oven includes a blower and a heat exchanger which together produce a circulation of hot air through a cooking portion of the oven at a uniform speed and with a uniform temperature distribution. The heat exchanger includes a plurality of generally U-shaped tubes disposed outwardly of the blower and uniformly spaced apart in a symmetrical relationship concentric to the blower. Each of the tubes has a first end in open communication with a first collector chamber in which hot combustion gases are generated by a gas burner and a second end in open communication with a second collector chamber. An exhaust device is connected to the collector chamber for exhausting combustion gases generated by the gas burner from the oven via the second collector chamber and the tubes of the heat exchanger. The exhaust device may in turn include an ejector for aspirating the exhaust from the oven through an exhaust pipe open to the second collector chamber.

Abstract: An apparatus (1) for baking food products includes an elongated tunnel (3) defining an oven (5). A conveyor (13) conveys food through the tunnel. Gas supplied to the tunnel is combusted by burners (43, 45) and the heat generated by the combustion is imparted to an upper hearth (17) and a lower hearth (19) by heat exchangers. The hearths radiate the heat into the oven to bake food product being conveyed therethrough and upper and lower sets of temperature sensors (93, 95) are provided to control the oven heat.

Abstract: An infrared burner with an extremely low pressure drop is described. The burner comprises a corrosion resistant mesh screen having a thick porous coating of ceramic fibers deposited thereon. In addition to a low pressure drop the burner has structural integrity and ability to generate radiant energy at a high rate. The burner is produced by admixing ceramic fibers with a polymeric material which burns off upon heating.

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: Radiant tube space heating appliance includes a burner assembly (12), air flow therethrough being induced by a fan (14) by way of a restricted air inlet orifice (34) communicating with a stabilizing chamber (32) leading to the burner head (26) for smoothing and silencing the air flow; the burner head including a flame stabilizing matrix (40), conveniently formed from windings of flat and corrugated stainless strips (42,43) which define through apertures of substantial axial length. The appliance may further include a turbulator insert (50) in the radiant tube formed as a corrugated strip (52) of stainless steel or similar material which is twisted to form a helix.

Abstract: A burner unit comprising three simple subassemblies which may be readily assembled to form the completed burner unit. The subassemblies include a front housing assembly including a front disk and a front tube; a back housing assembly including a back disk and a back tube; and a burner subassembly including a burner nozzle and a control assembly offset with respect to the central axis of the burner nozzle.

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: This invention relates to a sauna device with an infrared ray radiation sauna heater such that cooling air is introduced into the infrared ray radiation tube heated by combustion heat of fuel such as gas or the like to lower the temperature of the infrared ray radiation tube and radiate far infrared ray absorbable into the human body.It can be made up as the compact sauna device usable in home equipping the combustion devices in a box like mechanic chamber (114) placed at lower portion of the seat (111) in the sauna chamber.It is able to assemble, as the rear wall (102), the side walls (105, 107) the front wall (108) and the ceiling plate (104) can be assembled by engaging the project and groove joint.Attaching laundry rod holders (2210-1, 2210-2) containing a safety switch in the sauna chamber, on which the laundry rod (2209) is hung, it is available to use the sauna chamber as a drying chamber for laundry.

Abstract: A premix furnace burner for a gas combusting furnace. The furnace burner includes a premix chamber and a burner plate assembly. The burner plate assembly is comprised of a burner plate with a plurality of relatively small apertures for the passage of a mixture of combustible gas and air and an annular ring for retaining the burner plate. The annular retaining ring determines the capacity of the furnace burner by appropriately sizing of the opening in the annulus of the retaining ring to sealingly overlay a selected portion of the burner plate apertures. The retaining ring further secures the burner plate in the correct operational position while simultaneously permitting the burner plate to expand and contract in response to temperature changes induced by combustion of the gas and air mixture.

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: A radiant tube burner is presented comprising a gas burner having a divergent flame type nozzle at its end and designed to be movable in the axial direction while placed coaxially in a combustion tube, primary air swirling vanes located at the end of the burner for forming a swirled flame and an air damper fitted on a primary air supply tube connected to the combustion tube for adjusting the primary and the second air ratio, whereby soft two-stage combustion takes place in the radiant tube. Generation of NOx is greatly reduced with the newly invented burner.

Abstract: An efficient gas-fired bayonet-type heater has been developed to challenge the dominant position long enjoyed by the electric bayonet-type heater. The new heater replaces the electric resistance element in the bayonet-type heat exchange shell with a tubular porous fiber burner having a high length-to-diameter ratio attached to a long feed tube for the gas-air mixture. An annular space around the burner and feed tube within the shell provides the path for the combustion gases to flow to a discharge opening near the entry point of the gas-air mixture.

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: A far-infrared radiating system comprises a far-infrared radiating element (2) such as a ceramic, adhered to a metallic material (1) and radiating far-infrared rays upon heating. The system is constructed of a primary-radiating element (5) which is made of a metallic material while heated by a combustion gas passing therethrough and a secondary-radiating element (3) provided with the far-infrared radiating element (2) adhered to the metallic material (1). The primary-radiating element (5) is spaced apart and oppositely disposed from the secondary-radiating element (3) which is heated by infrared rays radiated from the primary-radiating element (5) having been heated with a combustion gas passing therethrough, whereby the secondary-radiating element (3) radiates far-infrared rays.

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 burner unit comprising three simple subassemblies which may be readily assembled to form the completed burner unit. The subassemblies include a front housing assembly including a front disk and a front tube; a back housing assembly including a back disk and a back tube; and a burner subassembly including a burner nozzle and a control assembly offset with respect to the central axis of the burner nozzle.

Abstract: An insulated reflector for a low-intensity radiant energy heating system. Several embodiments are disclosed. In one embodiment, the reflector forms a chamber which is used to preheat fresh air admitted to the heated area.

Abstract: A relatively low temperature, low-intensity infrared heating system in which at least a substantial portion of the effluent in the emitter tube is recirculated and mixed with the hot effluent from the burner of burners to produce a uniform system temperature. A relatively long low-temperature exhaust leg is utilized to increase thermal efficiency. The burner or burners receive combustion air from outside the enclosure and valves are used to prevent reverse flow.