Abstract: The improved incinerator is a concentric elongated tubular array, with an outer closed tubular housing or shell, an annular tubular heat exchanger in the form of a bundle of spaced open ended tubes inside the housing and spaced inwardly therefrom to define an annular air passageway therebetween and front and rear spaces, and a tubular combustion chamber having an open front end and an open rear end. The front end thereof is necked down and in the form of a small diameter tubular inlet immediately downstream of the combustion zone in the combustion chamber. A fuel line, a fluidized waste material line and an ignition system pass through the inlet into the combustion zone, along with heated air to initiate and maintain the desired complete combustion of the waste material. The air is preheated by blowing it into the passageway and around and over the heat exchange tubes, before passing it into the combustion zone.

Abstract: A pair of regenerative burners is provided with feed means (25) for feeding a reducing agent into the products of combustion so that this agent can reduce oxides of nitrogen in the heat store to which heat is imparted by the products of combustion. Refractory elements (17,21) comprised by the heat stores may additionally or alternatively have catalytically active surfaces to promote reaction of the lower oxides of nitrogen.

Abstract: The heat recuperator of a burner for an industrial furnace makes use of a substantially cylindrical body of ceramic produced by extrusion in which there are two interleaved sets of parallel channels, one set for the flow of combustion product gases out of the furnace and another set for the supply of air to be preheated in the recuperator and delivered to a combustion chamber coaxial with the recuperator and possibly located at least in part in the end portion of the cavity surrounded by the cylindrical ceramic body. The combustion product gases and the air being preheated flow in countercurrent and the disposition of the sets of channels facilitates heat transfer. The combustion chamber is constituted entirely of ceramic parts. A jet nozzle is provided on the outlet side of the combustion chamber and a fuel lance passing through the middle of the recuperator body and into the combustion chamber may also serve to adjust the jet nozzle by means of a valve body around its tip.

Abstract: An appliance for the combustion of oxidizable substances in a carrier gas is described, in which the carrier gas is fed through heat exchanger tubes having inlet ends which are bent outwardly adjacent an outlet for gas from which oxidizable substances have been removed by combustion. Prior to entering the tubes the carrier gas passes an annular chamber in which it becomes pre-heated and condensates are evaporated.

Abstract: A method and apparatus for repressing NOx formation in twinned regenerative burner pairs includes inducing a stream of hot flue gas, preferably containing enriched products of combustion, from the main hot flue gas exhaust stream and vitiating the preheated combustion air with the hot flue gas in the firing burner. An interconnecting duct communicating with the twinned burner pair includes a coaxial gas nozzle for injecting a high kinetic energy gas stream into the exhausting hot flue gas to induce a portion of the hot flue gas into the interconnecting duct to pass the hot flue gas to the firing burner for vitiation purposes.

Abstract: A regenerator for a regenerative heating system comprises a chamber 2 for storing a heat storage bed in the form of discrete particles 45, a closable inlet 16 for introducing fresh particles into the chamber 2 to replace contaminated particles and a closable outlet 18 for removing the contaminated particles from the chamber 2 so that the fresh particles may be introduced.

Abstract: Improved combustion of liquid fuel is achieved with a porous fiber burner by forming a mixture of the vaporized fuel and all of the desired combustion air sufficiently heated to prevent condensation of the vaporized fuel, and introducing the heated mixture into the porous fiber burner to effect flameless combustion on the outer surface of the burner. The resulting surface combustion produces a high proportions of radiant heat and increased thermal efficiency while suppressing the formation of nitrogen oxides and other pollutants in the flue gas. Periodically, fuel gas may be supplied to the same porous fiber burner.

Abstract: A vaporizer for liquid fuel for producing a fuel-air mixture including a orization member for the fuel and which is arranged within a flow chamber for combustion air. The surface of the vaporization member which is streamed against by the combustion air is moistened with fuel. The vaporizer incorporates a vaporizing member arranged within a flow chamber for combustion air, wherein the vaporizing member includes a rotatable or circulating filling or charge of balls whose temperature can be adjusted through heat conduction received from the walls of the flow chamber. Thereby, through the revolving or circulation of the ball filling, and the heat transfer to the balls which are currently at the edge of the ball filling in heat-conductive communication with the temperature-regulated walls of the flow chamber, there takes place a rapid and uniform heating of the ball filling.

Abstract: A recuperative burner comprises an outer annular two part duct 13 and 14 for supplying combustion air to four axially aligned chambers 15 located radially inwardly of the ducts 13 within the annular space between the duct 14 and a central fuel pipe 23. The combustion air enters the burner by way of an inlet 9 before entering the outermost duct 14. The air then travels along the innermost duct 13 and enters each chamber 15 by way of an inlet 20. The air then flows forwardly along each chamber 15 before leaving the chamber 15 by way of an outlet 21 before mixing with the fuel leaving a nozzle 24 at the outlet end of the fuel pipe. Waste gas flows in the spaces 22 between the chambers 15 in a direction opposite to the direction of air flow in the chambers 15 before leaving the burner 1 by way of an outlet 11. Heat from the waste gas is transferred to the air flowing in each chamber 15 and to the air flowing in the annular duct 14.

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: 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 combustor for use in an external combustion engine having a rotary-type regenerator heat exchanger includes a housing having a combustion chamber, an air chamber, a plurality of first outlet ports, and a first inlet port. A main partition defining the combustion chamber and the air chamber in the housing has a plurality of second outlet ports defined in a peripheral portion thereof and a second inlet port defined in a central portion thereof. An annular regenerator is rotatably supported in the housing, dividing the air chamber into first and second chambers, the regenerator having first and second axially opposite end surfaces and a multiplicity of axial through-holes extending therebetween. First subpartitions define first outlet passages communicating between the first outlet ports, respectively, and the first end surface of the regenerator, and divide the first chamber into air and exhaust sections.

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 gas burner comprises a ceramic tube through which a gaseous fuel flows, a chamber surrounding the ceramic tube, and means for delivering preheated combustion air to the chamber. There is a venturi around the tip of the ceramic tube, angled with respect to the tube, through which the preheated combustion air flows. The venturi enhances mixing of the air with the gaseous fuel forward of the tip of the ceramic tube.

Abstract: The present invention relates to a method and apparatus for waste heat recovery and reduction in industrial furnaces and heating equipment. The method of heat recovery comprises directing the exhaust gases through a system of channels inside the refractory wall where heat from the flue gases is transferred to the refractory lining and also to the combustion air traveling inside of a heat exchanger also located inside said channels. The high temperature exhaust flue gases traveling along said channels increase the hot face temperature of the refractory wall and reduce the heat flux from the working chamber through the refractory wall. An apparatus for the realization of the heat recovery method includes a flue duct, a recuperator, hot air piping and a hot air burner, all located inside the furnace wall refractory lining.

Abstract: A burner assembly of a type wherein both the combustion air and gaseous fuel are controlled by a pressure equalizing control device comprises an inner barrel and a combustion air preheating passage both arranged exteriorly of a gaseous fuel supply tube, an annular space defined exteriorly of the gaseous fuel supply tube and communicated with the preheating passage through at least one perforation in the inner barrel, and an exhaust passage provided with an exhaust gas sucking device and disposed adjacent the preheating passage.

Abstract: The present invention relates to a process and a device for preheating by combustion gases, a combustive gas intended to be mixed with a combustible gas before its combustion, comprising a box member containing a first, upper vertical exchanger in which the combustive gas is first heated by heat-exchange in counter-current relationship to itself and then in co-current relationship to the combustion gases, and a second exchanger incorporated in a burner and arranged below the first exchanger, the second exchanger allowing the combustive gas to be heated by heat exchange in co-current relationship and then in counter-current relationship to the combustion gases to finally be mixed with the combustion gas.

Abstract: A heat exchanger-combustion chamber construction includes a combustion chamber and a heat exchanger chamber. Disposed in the heat exchanger chamber is an array of inlet tubes, the outlets of which discharge into the combustion chamber. Combustion products discharged from the combustion chamber are flowed over the inlet tubes in heat exchange relation. An array of aspirator sleeves of larger inner dimension than the outer dimension of the inlet tubes is secured to divider structure between the heat exchanger chamber and the combustion chamber, each aspirator sleeve receiving the outlet end of a heat exchanger tube while permitting longitudinal movement of the heat exchanger tube within the sleeve (due to thermal expansion, for example).

Abstract: A burner for gaseous or liquid fuel for heating furnaces includes a ceramic combustion chamber (20) for incomplete combustion of the fuel with primary air from which hot gases exit at high velocity through a constricted outlet (24). The combustion chamber is surrounded by a chamber (42) for the preheated remainder air necessary to complete combustion. Out of this chamber high velocity jets of air issue through nozzle openings encircling the combustion chamber outlet. Energy is saved and simple construction maintained by providing a tubular heat recuperator (4, 7, 9) rearwardly of the combustion chamber in which a cylindrical wall of temperature resistant steel passes to separate the recuperator into two annular chambers (10,11) and extends forward over a large part of the axial length of the combustion chamber so as to form an outer boundary of the remainder air chamber.

Abstract: In a method in the operation of a firing plant of the type comprising a combustion furnace and heat exchanger means to transfer thermal energy from the flue gas of the furnace to its combustion air, wherein a vaporizable liquid, such as water, is added to the combustion air of the furnace, the combustion air pressure is reduced in the portion of the heat exchanger means where the said liquid is caused to evaporate, the necessary evaporation heat being taken from the flue gas of the furnace before the flue gas is discharged to the atmosphere. A plant for performing the method is characterized by containing a pump (11) which has a relatively small inlet opening (10) so that the pump (11) creates a negative pressure in the portion (12) of the heat exchanger (9) where the liquid, fed by means of a nozzle (13), evaporates. This allows large amounts of water to evaporate, and flue gas, which flows through the heat exchanger portion (14), is cooled to a low temperature.

Abstract: A ceramic burner head in which the burner mouth is formed from a unitary porous ceramic body with parallel slits defining fuel-permeable walls between and which is bonded to upper, lower and lateral ceramic plates forming the burner body. The ceramic piece is bonded to the plates in a gas-tight manner.

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: A heat regenerator for use in heating an enclosure such as a furnace.The heat regenerator 51 is detachable at one end from a burner B and at its other end from a reversing valve 58. The regenerator 51 comprises two axially engaging portions 56 and 57, the front portion 56 comprising a cylindrical heat storage bed 59 and a surrounding annular layer 60 of a ceramic fibre insulation material. The rear portion 57 comprises a cylindrical body of refractory having a bore 61 forming a bottle-neck type passage tapering towards the valve 58. The heat storage bed 59 comprises a monolithic refractory block through which a multiplicity of axially aligned gas-carrying channels 65 extends. These channels 65 convey combustion products from the burner portion 52 to the regenerator portion 56 in one mode of operation where the bed is extracting heat from the products for storage.

Abstract: A combustion apparatus for burning liquid fuels has a burner for atomizing and burning the liquid fuels. Oxygen enriched air, obtained by passing normal air through an oxygen permselective membrane, is supplied to the burner as air for combustion.

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: 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 pair of burner tubes are arranged in concentric relationship. Fuel and air in a rich fuel-air ratio is provided to the central burner tube, and fuel and air in a lean fuel-air ratio is provided to the outer burner tube. The rich combination of fuel and air is partially burned at a temperature of about 2,500.degree. F. while the lean combination of fuel and air is burned at a temperature of less than 2,800.degree. F., and the flames from the burner tubes are mixed at the ends of the burner tubes to form a final flame envelope and to finish the combustion of the rich mixture. Exhaust gas is directed about the burner tubes, and combustion supply air is circulated about and preheated by the exhaust gas conduits and the outer burner tube. The separate combustion of the rich and lean fuel-air mixtures at relatively low temperatures and the subsequent mixing of the flames from the burner tubes results in low NOx emissions and results in high luminosity of the final flame envelope.

Abstract: A recuperative burner having a recirculating conduit to direct flue gas to the combustion chamber with the air and fuel, and a compact recuperative stack with a recuperative flue gas conduit and an air passage in which air separated from the flue gas by the recuperative flue gas conduit is preheated before supplying it to the combustion chamber.

Abstract: A burner for burning a low Btu gas including at least one set of fine ducts and at least one combustion chamber disposed on the downstream side of the set of fine ducts for obtaining combustion of the low Btu gas. Combustion gas produced in the combustion chamber heats the combustion chamber and the set of fine ducts through a wall of a combustor.

Abstract: A vaporizing apparatus includes a vaporizing chamber for producing vapors from a hydrocarbon fuel which are drawn into a mixing chamber by pressurized air, and the mixture is delivered to a manifold where a portion is return to the vaporizing chamber and ignited for heating and vaporization, a safety control system sensing the presence of a flame and the temperature of the vaporization chamber and interrupts flow of vapors when the flame is absent or the temperature is outside prescribed limits. A starter burner which uses the hydrocarbon fuel as a combustible material for preheating the vaporizing chamber is also automatically shut off by the control system when the vaporization chamber reaches the operating temperature. The starter burner includes a mixing valve and a combustion chamber with mixing chamber therebetween for drawing ambient air into the mixture of pressurized air and combustible material.

Abstract: A flue gas heat recovery apparatus for reconstituting thermal energy normally lost through the venting of flue gases from a heat liberating plant is disclosed. The apparatus can be employed with forced air or hydronic systems and includes a compressor which draws hot gases from the exhaust flue through a first heat exchanger located in a cold fluid return to the plant, thereby transferring thermal energy from the gases to fluid (typically air or water) flowing in the return duct. The compressor operates to substantially elevate the pressure and temperature of the flue gases passing therethrough and discharges them through a second heat exchanger located in the return duct upstream of the first heat exchanger to further transfer thermal energy from the gases to the fluid flowing therein. Gases exiting the second heat exchanger are directly vented to the atmosphere or, alternatively, are first filtered to remove particulate matter.

Abstract: The invention is a recuperative burner, with heat exchange between the exhausting combustion products and incoming combustion air to the burner nozzle, in which the recuperator essentially comprises separable components of conical shape. The advantages are ease of dismantling, even if the conical components have distorted in use; improved flexibility of design, resulting in better efficiency and reduced formation of nitrogen oxides; and lower costs for both manufacture and maintenance.

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: Apparatus for heating the fuel oil exiting from an oil supply tank and in the supply pipe leading to an oil burner furnace. The return oil line, from the pressure relief valve in the oil burner unit, is led to a coil fitted about the furnace stack leading from the oil burner furnace. The outlet of this heating coil is then led into a metal tempering box, mounted below the tank, through a pipe banded to the supply pipe so as to warm the oil in the supply pipe and the oil in the tempering box. Supply oil is fed from the oil supply tank into the tempering box, to mix with the heated oil in the tempering box, with the mixed warmed oil led from the tempering box into the supply pipe leading to the oil burner of the furnace.

Abstract: A method and plant for recovering heat from smoke gases in combustion plants, whereat the combustion air is compressed prior to being supplied to the combustion chamber of the plant. The compressed smoke gases from the combustion chamber are cooled, at a pressure which exceeds 1.5 atmospheres, to a temperature beneath 100.degree. C., preferably beneath 80.degree. C., and are then caused to expand in a turbine, whereat the energy released by said expansion is utilized for compressing the air of combustion.The plant comprises one or more compressors (2) which are arranged upstream of the combustion chamber (6) of the combustion plant and which compress the air of combustion; and a turbine (9) arranged downstream of the combustion chamber or chambers (6) for expanding the compressed smoke gases.

Abstract: To improve the overall efficiency of heat recuperation in a burner installation, an additional or auxiliary heat exchanger (25) is positioned adjacent the burner (4) immediately behind a heat exchanger recuperator (12) for combustion air, the additional heat exchanger having a heat carrier medium, such as water, pressurized water, heat transfer oil, or the like, circulated therethrough for recuperation of additional heat from the exhaust gases and utilization, for example for space heating, hot water supply, or the like, in a further heat exchanger (28). The heat transfer efficiency of the burner system can thereby be improved to provide for a burner operating at for example 1000.degree. C., of final exhaust gas temperatures in the order of 200.degree. C. which, without the additional or auxiliary heat exchanger, would be exhausted at about 500.degree. C.

Abstract: A fluid-heating apparatus comprises a ceramic burner head formed with narrow passages which alternate with one another for fuel and a combustion sustaining medium such as air, the slit-like passages opening into a combustion chamber at which combustion of the fuel/air mixture occurs. Downstream of this combustion chamber is a ceramic recuperator likewise formed with slit-like passages, the hot combustion gases traversing some of these recuperator passages while the fluid medium to be heated is passed through others of these passages so that heat exchange is effected through the thin ceramic walls supporting the slit-like passages of the ceramic recuperator.

Abstract: An apparatus for generation of steam in a borehole for penetration into an earth formation wherein feedback preheater means are provided for the fuel and water before entering the combustor assembly. First, combustion gases are conducted from the combustion chamber to locations in proximity to the water and fuel supplies. Secondly, both hot combustion gases and steam are conducted from the borehole back to the water and fuel supply. The water used for conversion to steam is passed in a countercurrent manner through a plurality of annular water flow channels surrounding the combustion chamber. In this manner, the water is preheated, and the combustion chamber is cooled simultaneously, thereby minimizing thermal stresses and deterioration of the walls of the combustion chamber. The water is injected through slotted inlets along the combustion chamber wall to provide an unstable boundary layer and stripping of the water from the wall for efficient steam generation.

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

Abstract: An apparatus and method for utilizing the heat of waste gases by exhausting the same at the head of a flue from a source into a heat extractor where the hot gases are caused to move and turbulate about heat exchanger walls to release their heat to such walls before being exhausted downward to the atmosphere so that fluids moved through the heat exchanger may be heated to perform useful work.

Abstract: A ceramic recuperator for the heating of combustion air, e.g. for an oil-fired burner or boiler, which prepares at least the air in the formation of a fuel-air mixture which is ignitable at the burner. According to the invention the recuperator is provided with means, especially electrically operated for heating the ceramic body so that the initial combustion air can be heated before firing of the burner and the further heating of the recuperator by combustion products.

Abstract: A combustion device of the type in which fuel is supplied in liquid phase through a "walking-stick" is improved by imparting a rotary movement to the air passing the "walking-stick". The fuel will form a film which is volatired and mixed so thoroughly with air that the temperature at the end of the "walking-stick" may be used as an indication of the prevailing proportion between the mass flows of supplied air and fuel.

Abstract: A burner head of ceramic materials through which the fuel (combustible) and the oxidizing agent (oxygen or oxygen-containing gas such as air) are passed from an inlet side to an outlet side, combustion being effected at the outlet side. According to the invention, the gas passages for the fuel and the oxidizing medium are of elongated cross section and parallel to one another, being offset in pairs so that indirect heat exchange is effected between the two mediums through the separating ceramic wall. The passages can be formed as rectangular-section channels which are closed at the top and bottom by ceramic plates.

Abstract: The furnace system has a heating chamber wherein a rich combustion mixture is fed. The mixture has been preheated within a regenerator and the flue gas is ducted to another regenerator which is also fed with secondary air to more completely oxidize the flue gas. Part of the hot flue gas leaving the second regenerator is tapped and recirculated to the heating chamber and the remaining flue gas being fully oxidized is vented to the atmosphere. When the first mentioned regenerator becomes too cold to preheat the combustion mixture, given valves are opened and closed so that the combustion mixture first is preheated within the second regenerator, then burned, and directed to the heating chamber and the incomplete combustion flue gases are now ducted to the first mentioned regenerator to be completely oxidized as described before, and, in turn, to heat this regenerator.

Abstract: A gaseous fuel combustor for a Stirling engine includes a shell mounted on the engine, and air inlet and exhaust ports formed in the shell. An annular cylindrical recuperator communicates with the inlet and exhaust ports for preheating the combustion air with the heat from the exhaust. An annular burner surrounds the dome shaped engine heater head for mixing gaseous fuel with the air and burning it at the outer peripheral edge of the heater head. The combustion products converge upwardly in a narrow space between a ceramic partition and the heater head dome so that the heat flux is constant. The combustion products exhaust through a axial hole in the center of the ceramic partition and travel back outward over the top of the partition to the annular recuperator.

Abstract: A burner system in which an ignitable mixture is formed from vaporized liquid fuel and preheated air which is heated by recuperative heat exchange with a furnace exhaust gas from the combustion chamber in which the mixture burns. According to the invention, a feed line for the fuel opens into a closed chamber provided with porous walls permeable to the fuel and with a flow passage traversed by the preheated air, the wall of this flow passage in turn serving for indirect heat exchange of the air by the combustion gases of the furnace.

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: Recuperator burner for industrial furnaces with a central fuel tube which ads the gaseous fuel into a combustion chamber, which tube is concentrically surrounded by a combustion-air supply tube, the outer surface area of the combustion-air supply tube in the area of the recuperator being able to be applied with the exhaust gases which are guided in counterflow through an outer jacket tube and in which combustion-air supply tube there is arranged a first tubular separation wall. The separation wall first guides the combustion-air stream on the way to the combustion chamber along the central fuel tube up to the outlet-side end range of the fuel tube and then redirecting the combustion-air stream in reversed direction.

Abstract: A method and apparatus for making holes in coal seams in a coal mining system in which hot working gas is employed to impinge on the coal under high pressure and speed in order to disintegrate it and particularly for making inclined or horizontal holes which connect vertical drill holes which lead from the surface to the coal seam and through which the medium for gasifying the coal underground is blown in. The vertical drill holes which lead from the coal seam to the surface are used for blowing out gasification gases which are produced by the operation as well as for delivering the hot working gas. With the method of the invention, a gasification medium of high temperature and pressure is advantageously produced directly at the locations where the disintegrated coal is gasified, the disintegrated coal being formed by a rocket combustion process.