Abstract: A recuperative radiant tube heating system in which a recuperator tube telescoped into a radiant tube and over a burner assembly is formed as three interconnected sections to facilitate manufacture of the recuperator tube, to facilitate assembly of the recuperator tube with the burner head of the burner assembly and to enable easy replacement of that portion of the recuperator tube which is most susceptible to burn out. The burner head includes a nozzle having gas discharge ports which are angled in such a manner as to effect good mixing of the gas with combustion air while reducing the likelihood of the ports becoming clogged with carbon.

Abstract: A radiant heater comprises first and second reflector portions (1, 2); first and second side reflector plates (3, 4); first and second end reflector plates (5, 6); first and second steel U-tubes (7, 8) received by the first and second portions (1, 2) respectively; end reflector plates (9, 11) for the reflector portion (1) and end reflector plates (10, 12) for the reflector portion (2), the ends of the tube (7) protruding through the plate (9) and the ends of the tube (8) protruding through the plate (10); first and second gas (or oil) burners and control units (13, 14) communicating with the ends of tubes (7, 8) respectively nearer a V-shaped channel; and first and second suction fan units (16, 17) communicating with the ends of tubes (7, 8) respectively which are further from the channel (15). In use of the heater, gas (or oil) is burnt at the burners and control units (13, 14), and hot air is sucked through the tubes (7, 8) by the suction fan units (16, 17).

Abstract: Oxygen is introduced through oxygen supply line (5) into an annular gallery (6) which it leaves at high velocity through annular channel (7). The outlet of the annular channel (7) is shaped so that, by virtue of the Coanda effect, the oxygen travels towards the downstream end of the burner (1) substantially parallel to the wall of the tubular body (2). Combustion gas from combustion chamber (13) is induced between support bars (4) into the tubular body (2) by the flow of oxygen and mixes with the oxygen and subsequently with natural gas introduced through fuel supply line (8). The mixture burns at the outlet (9) of the fuel supply line (8). The maximum temperature reached by the gas leaving the burner (1) is substantially lower than that which would be obtained by a conventional oxy-fuel flame. The burner may be used in radiant tubes.

Abstract: A burner assembly for heating a U-shaped radiant tube. The burner assembly includes a generally conical burner nozzle supported on the end of a gas supply pipe and disposed within an inner tube which, in turn, is located within the radiant tube. The burner nozzle may be adjusted selectively back and forth within the inner tube to change the ratio of primary and secondary combustion air supplied to the nozzle and thereby change the length of the flame produced by the burner assembly.

Abstract: A gas convection oven includes a heating chamber having a gas combustion chamber formed therein and a blower positioned within the combustion chamber for circulating air through the heating and combustion chambers. The blower defines a low pressure inlet centrally of the combustion chamber for receiving air from the heating chamber and forcing it through the combustion chamber back into the heating chamber around the outer edges of the combustion chamber. A gas burner extends into the combustion chamber and includes a distally-mounted diverter for dividing and directing flame and combustion products into two different directions. A bifurcated heat exchanger defines first and second tubular passages which are aligned with and encompass the blower and define inlets aligned with the two different directions for receiving the combustion products from the burner.

Abstract: A flame radiator structure is disclosed for inhibiting formation of oxides of nitrogen (NO.sub.x) by a combustion system of the type having at least one monoport inshot burner which burns fuel to produce a combustion flame which is projected through an inlet opening into a heat exchanger for the combustion system. The flame radiator structure comprises a perforated, tubular, main body section having open ends and means for attaching this perforated tubular main body section at the inlet to the heat exchanger. Alternating ribs and oblong openings are spaced along side walls of the perforated main body section to stiffen the structure and to allow the structure to safely expand and contract in response to thermal cycling.

Abstract: An ultrasonic atomizing burner for smaller heating apparatus particularly for mobile spaces, such as motor vehicles comprises an atomizer which has a fuel inlet and which is equipped with an atomizer discharge plate and a structure skirting the plate which defines a combustion air flow space for 1% at most of the combustion air amount. This structure includes a cylindrical combustion chamber having a forward discharge end with a flame baffle and with a heating gas outlet tube connected to the discharge end for the axial flow of the combustion gases. The combustion chamber has an ignition zone which is provided with wall bores for admitting primary air and it includes a spark plug in the ignition zone for igniting the combustion gases and the primary combustion air. The combustion chamber also has a burnout zone which is provided with wall slots for admitting secondary air downstream of the primary air.

Abstract: A burner for use in a heat regeneration system for a combustion furnace. The burner includes a burner shell having two internal chambers, wherein the first chamber is disposed on the flame axis of the burner, and the second chamber surrounds the radial perimeter of the first chamber. A gas permeable, annular regenerative bed separates the first and second chambers such that gas flow between the first and second chambers must travel through the regenerative bed in a direction which is generally radial with respect to the flame axis. The burner has "flue" and "fire" modes of operation. Valving elements are included for supplying combustion air to the second chamber under pressure when the burner is in the fire mode, and for exhausting products of combustion (POC) from the second chamber when the burner is in the flue mode. In the disclosed embodiment, the burner valving elements are annular and integral with the burner body.

Abstract: Oxygen is introduced through oxygen supply line (5) into an annular gallery (6) which it leaves at high velocity through annular channel (7). The outlet of the annular channel (7) is shaped so that, by virtue of the Coanda effect, the oxygen travels towards the downstream end of the burner (1) substantially parallel to the wall of the tubular body (2). Combustion gas from combustion chamber (13) is induced between support bars (4) into the tubular body (2) by the flow of oxygen and mixes with the oxygen and subsequently with natural gas introduced through fuel supply line (8). The mixture burns at the outlet (9) of the fuel supply line (8). The maximum temperature reached by the gas leaving the burner (1) is substantially lower than that which would be obtained by a conventional oxy-fuel flame. The burner may be used in radiant tubes.

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: A heat exchanger for heating air supplied to a burner is described. The heat exchanger includes two passages. One of the passages provides a channel through which combustion gas is exhausted from the burner while the other passage provides a channel through which air is supplied to the burner. The two passages are arranged to transfer heat from the combustion gas to the combustion air. Each of the passages includes a helical guide baffle for directing fluid through each respective passage substantially along a helical flow path. The helical guide baffles of the passages each exhibits a variable pitch which changes at a predetermined rate to maintain the pressure and velocity of the fluid in the respective passages within predetermined limits.

Abstract: A ceiling radiation heater has a plurality of hot-air radiation pipes arranged as high as possible below the ceiling at a distance from the ceiling and from each other in one or several planes longitudinally parallel side by side and combined in groups, with reflectors behind which thermally insulating layers may be provided arranged above and laterally of the pipes. Combustion gases and/or waste heat available from production processes may be introduced into the air-filled, closed hot-air radiation pipe system.

Abstract: A method of burning a fuel gas in a low NO.sub.x level in the exhaust gas is disclosed, wherein a radiant tube burner having concentrically arranged outer air flow nozzle, fuel gas nozzles arranged in a circle and inner air flow nozzle and having a particular structure is used and the fuel gas is burnt under a particularly limited condition.

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: A process for the surveillance of jacketed radiant heating tubes and recuperative burners using a detector responding to the oxygen partial pressure in the exhaust gas. At low exhaust gas temperatures down to 200.degree. to 300.degree. C., an abrupt change in the detector output signal occurring due to the transition from over-stoichiometric to under-stoichiometric combustion and vice-versa is detected and is reproduced as an actuating and/or alarm signal. The process can also be used for flame surveillance, for the determination of leaks and cracks in jackets, and for surveillance of the tightness of closed magnetic gas valves.

Abstract: A gas-fired infrared heater for projecting an infrared beam in a radiation pattern having a predetermined geometry for irradiating the surface of a food product or other body to effect uniform heating thereof at a rapid rate. The heater includes a ribbon-type burner having an elongated pre-mix casing into which is fed air and gas, and an outlet extending along a slot in the casing and projecting therefrom. The outlet is provided with two sets of corrugated ribbons separated by a gas pressure chamber, whereby the air-gas mixture from the casing passes through one set into the chamber where the pressure thereof is equalized before the mixture passes through the other set from which it emerges as a sheet of flame of uniform intensity. The outlet is inserted in the longitudinal socket of a refractory body to impinge on a surface thereof whereby the surface is heated to a temperature level causing the surface to emit infrared energy which is projected by an array of radiation horns formed in the assembly.

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: Heating apparatus is described that is particularly adapted for thawing frozen particulate material in railroad hopper cars. The apparatus is a low profile, fuel-fired heater adapted for installation between rails traversed by the hopper cars within a thawing shed. The construction employs heat-radiating metal plates forming an elongated gas-conducting chamber through which high velocity combustion gases are conducted. The arrangement of plates is such as to enhance the emission of radiant heat to the hopper car bottoms with appropriately positioned heat insulated regions to protect hopper car brake hoses, or the like, from damage caused by overheating.

Abstract: The present invention relates to a fuel-fired heating element of the tubular kind particularly though not exclusively for use as an immersed heating tube in molten metals, salts or fluidized beds of solid particles for conductive heating or for use in an enclosed or partially enclosed chamber to provide radiant and convective heating.The element includes a tubular housing 1 having one end 2 closed and an opening to provide an outlet 4 for combustion products. A burner assembly 6 is received with an annular clearance 51 within the housing between the outlet 4 and the closed end 2 and is arranged to direct its combustion products as a stream towards the closed end 2.The tube 7 encloses with clearance three axially aligned tubes 60, 61 and 62 whose external and internal diameters decrease sequentially from the burner 6 to the end 2.

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 gas-fired convection oven for processing food, for example, having a fan for moving air along a circulatory path over, along and about the food to be processed. A package type gas burner outside the oven is directed into a heat exchanger tube of substantial length extending into the oven. High-temperature exhaust gases are discharged from the burner to be directed through the heat exchanger into the circulatory path of air flowing through the convection oven. Relatively proximate the burner the heat exchanger has a linear portion that is of elliptical cross section, and that portion is oriented with respect to the outlet of the convection blower and walls of the convection blower chamber to draw air over substantially the entire surface area of such portion for maximum cooling/heat exchange function with respect thereto.

Abstract: A radiant tube to be heated by high-temperature gases supplied from its one end. The tube supplys a heat radiation by being thus heated. The gases used for the heating are discharged from the other end of the tube. Inside the tube a heat exchanger is provided in the proximity of the gas outlet of the tube so as to recover thermal energy from the used gases before they come out from the outlet.

Abstract: A high efficiency induced draft clamshell type heat exchanger for use in a hot air furnace. The geometry of the heat exchanger is such that the various segments are compactly arranged to transfer heat from the fuel to the air passing over the heat exchanger surface while maintaining the discharged products of combustion at a temperature sufficiently high to prevent condensation from forming or collecting within the heat exchanger during steady state operation.

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: Thermal shock resistant catalytic monolithic structures are described comprising curved-surface plates with flow-through passages. Such structures are especially useful as combustor catalysts and their use in catalytic combustors permits much more rapid start-up and cool down than with conventional monolithic catalysts.

Abstract: A gas-fired infrared heater for projecting an infrared beam in a radiation pattern having a predetermined geometry for irradiating the surface of a food product or other body to effect uniform heating thereof at a rapid rate. The heater is constituted by a refractory assembly formed by a stack of identical slabs having a bore therethrough to receive the cylinder of a controllable ribbon-type gas-air burner from whose longitudinal slot is emitted a sheet of flame. Each slab is provided with a sector-shape channel cut in one face thereof to define a fin and side walls that diverge from the bore to create a flattened IR radiation horn whose mouth is aligned with the burner slot, whereby the surface of the assembly on which the flame impinges is heated to a temperature level causing this surface to emit infrared energy. The parallel array of radiation horns created by the assembly produces a radiation pattern whose shape depends on the geometry of the channel.

Abstract: The invention provides a complete heating system for large buildings in which waste process gas is circulated around a loop of duct which is above the space to be heated and radiates downwardly in said space. Purging and diluting air supplies into and from the duct are provided, and also separate input means for use when process gas is unavailable or unsuitable.

Abstract: A single-ended recuperative radiant tube assembly for increasing the efficiency of a combustion furnace system by using less fuel input per heat output than conventional systems. The single-ended recuperative radiant tube assembly has inner and outer recuperator tube assemblies positioned in a counterflow arrangement within a radiant tube assembly. Hot exhaust gases emitted from a burner within the single-ended radiant tube assembly are directed through a flame tube to an annular exhaust chamber located between the outer recuperator tube and radiant tube assemblies. Ambient air flowing towards the burner in an air chamber between the inner and outer recuperator tube assemblies is heated by the exhaust gases in the annular exhaust chamber.

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: A porous ceramic heating reactor is positioned within a tubular casing to contain the flame and the end products of combustion. A flattened portion of the casing extends substantially past the reactor to provide for further transfer of heat through the casing wall from the hot exhaust gases and to carry those exhaust gases to a safe point of exhaustion. The unit is essentially modular so that any number can be selected for an installation. The casing configuration enhances turbulent flow of the hot gaseous products of combustion. Turbulent flow increases heat transfer to and through the walls of the casing to the boilder or other area to be heated. The size and shape of the tubular casing provides an explosion proof, leak proof, efficient heat transfer device. Each reactor has a spark plug one of whose elements is a bi-metallic strip. In a multi-unit installation the spark plugs are connected in parallel across a spark generator.

Abstract: A torch type heating device has a removably mounted grid and pivotally attached handle assembly convertible to a tripod support to facilitate installation as a cooking apparatus and as part of a space heater assembly. Shields mounted adjacent opposite ends of the torch tube associated with the heating device, render the heating device wind-proof.

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: 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: An air heater for use in association with a radiant heating tube, the air heater comprising a heat exchanger having a combustion air inlet and a heated combustion air outlet, and a heated gas inlet and a heated gas outlet. The heated combustion air outlet has a transfer pipe connected thereto, an opposite end of the transfer pipe adapted to be connected to an inlet end of a radiant heating tube, and the heated gas inlet to the heat exchanger adapted to be connected to a discharge end of said radiant heating tube. The transfer pipe extending from the heated air outlet of the heat exchanger to an entrance to a radiant heating tube has an air control damper means situated therein. The end of the transfer pipe adapted to be connected to an entrance to a radiant heating tube has a venturi portion therein, an oil nozzle means being situated at inlet of the venturi portion of the transfer pipe adjacent the intake end of said radiant heating tube.

Abstract: A radiant burndown tube for furnaces which have a chamber sealable from the ambient atmosphere and in which there is a combustible gas. The burndown tube is divided into three functional areas; the burner leg, the exhaust leg and a tube portion. The tube portion is located within the furnace chamber. There is an inlet where the combustible gas from the furnace chamber is drawn into the burndown tube. The combustible gas is mixed with air and ignited in the tube and the combustion products are exhausted via the exhaust leg. Thus, the heat energy normally lost in the burndown of combustible furnace exhaust gases outside of the furnace is captured and used to provide additional heat to the furnace.

Abstract: A system for the transmission and conversion of the potential energy of hydrocarbon fuels to available heat, power and light. The system is particularly adapted for use with natural gas, artificial gases or any of the LPG fuels such as propane, butane, etc. According to the system of the invention, the fuel gas is mixed with air preferably in the amount providing the stoichiometric ratio to oxygen and is stored under pressure and ultimately transmitted to burner elements which are hermetically sealed except for the inlet and discharge ports, such as tubes, power sources, such as captive and free piston devices and gas turbines and light sources. The system includes special forms of equipment for mixing and pressurizing the gas and air in the correct ratio and special forms of equipment for establishing and controlling the combustion processes.

Abstract: In a tank immersion heating system a conical casing surrounds the high intensity fuel burner with its narrower end communicating with the immersed tube to introduce combustion air with progressively increasing velocity so that although flame "lift-off" is avoided combustion takes place mainly within the tube.

Abstract: A jet pipe burner for heating the interior of an industrial furnace includes a jet pipe and a burner head positioned within the jet pipe. An air pipe and a gas pipe provide combustion air and fuel gas to the burner head. A gas-air mixer is connected to the air pipe and the gas pipe for mixing the combustion air and the fuel gas before they flow to the burner head. A valve, connected to the mixer, controls the supply of combustion air and fuel gas to the burner head. In one embodment a ring-shaped air duct is arranged coaxially with and laterally enclosing the burner head for cooling the burner, the ring-shaped air duct has nozzles which open into the jet pipe. A conduit connected to the source of combustion air delivers cooling air into the ring-shaped air duct. In another embodiment radially projecting cooling plates formed of heat resistant material are angularly distributed about the circumference of the burner head.

Abstract: A heating assembly for a heat treating furnace is disclosed which includes a heating tube from which heat is transferred to the furnace and a burner disposed in the heating tube. The burner is connected to a source of mixed fuel and air and is constructed to define a mixture inlet section, a throat section and a discharge section. A primary mixture flow passage is defined by the throat section and secondary mixture flow passages communicate with the discharge section to impinge secondary mixture flows into the primary flow and impart a vorticular motion to the mixture flowing from the burner.The burner is constructed from a first relatively easily machined member which defines the inlet and throat sections and in which the secondary passages are formed. A second tubular cylindrical heat resistive member defines the discharge section and the members are shrink fitted together to enable reconditioning of the burner by replacement of the second member.

Abstract: In a generally elongated tubular burner heating element for the furnace chamber of an industrial furnace there is provided within the heating element at an end thereof opposite the end at which the burner is located a flame breaker assembly arranged to extend along the length of the burner heating element comprising a plurality of generally circular baffle plates spaced axially along the heating element and arranged basically in three groups. The first group of baffle plates which may comprise one or more plates and which is arranged closest to the burner comprises convex discs with their convex side directed toward the burner. The second group intermediate the first and the third group comprises a plurality of generally planer discs while the third group comprises concave discs having their concave side facing toward the burner.

Abstract: A fuel-fired radiant-heating tube for an industrial furnace is provided, at its fuel-feed end externally of the furnace, with an acoustic damper or muffler which comprises a double-wall housing defining two elongated annular flow passages in indirect heat-exchanging relationship through a thermally conductive inner wall. The combustion exhaust gases are conducted through one of these passages while combustion-sustaining gas, e.g. air, is supplied through the other in counterflow to the exhaust gas, thereby preheating the air. The outer wall is provided with acoustic and/or thermal insulation while at least one of the passages is provided with sound-damping elements, e.g. vanes for baffling the flow through this passage.

Abstract: A jet pipe containing a burner extends through the interior of an industrial furnace. A seal for sealing the interior of the jet pipe from the interior of the industrial furnace, is positioned between an end face of the jet pipe and a flange having a recess in which the end face of the jet pipe seats. The seal is made of a material, preferably a lead-copper alloy, which is in the solid state when the temperature of the furnace is below a predetermined operating range and which changes into the plastic state as the temperature of the furnace increases and reaches the operating range of the furnace. Preferably, the seal is shaped as an annular member with a cylindrical extension having an outside diameter corresponding to the inside diameter of the jet pipe.

Abstract: A bellows arrangement for forming a gas leakage resistant pressure seal between ceramic heat exchange tubes has an elongated metallic bellows defining a central passageway with first and second ends. A metallic tube passes through the bellows and freely moves with respect to the second end of the bellows while defining a gas chamber between the tube and bellows. Axial expansion of the bellows under the influence of the internal pressure when such pressure is higher than the external pressure which may be the atmosphere acts to apply a force at the interface between the bellows assembly and the ceramic heat exchange tube which is proportional to the internal pressure of the heat exchange tube, thereby accommodating movement of the heat exchange tube and providing a pressure seal that is leak resistant.

Abstract: Heating apparatus for a baking oven or the like wherein product to be heated or baked is conveyed through the oven, and a plurality of heating elements are arranged longitudinally along the path of product movement through the oven, the heating elements each comprising a conductive tube extending transversely across the path of product movement, a burner at one tube end for introducing a combustible mixture therein, and combustion products outlet means at the other tube end for discharge into the oven chamber.

Abstract: A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

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

Abstract: A combustible fuel gas burner has a primary tube supplying gas and primary air to a main burner, a secondary tube supplying secondary air to the main burner to afford complete combustion, and an exhaust tube through which the products of combustion are exhausted. The exhaust tube also acts as a flash-tube for igniting the main burner. In the absence of combustion, the gas and primary air issuing from the primary tube and the secondary air issuing from the secondary tube combine to form an air-gas mixture in the exhaust tube which is too lean (below the lower limit of flammability) to be ignitable. The supply of secondary air is controlled so as to vary the air-gas ratio in the exhaust tube such that this ratio changes through a spectrum of values between the lower and upper limits of flammability wherein the flame propagation speed of the mixture is substantially greater than the flow velocity thereof.

Abstract: A radiantly heated furnace is provided with a heating arrangement capable of generating heat from two different sources of energy. The arrangement includes a thin-walled tube extending within the furnace which operates as a resistor when connected to a high current source of electrical energy to generate and radiate heat within the furnace. The thin-walled tube also acts to radiate heat into the furnace from hot burner gases injected therein by a fuel fired burner. The arrangement is so constructed that switching from the electric to the gas fire mode or vice versa can be swiftly effected without removal of electrical connections or burners.