Abstract: The present invention explains a multi-fuel combustion system. It consist of a combustor basket adapted to combust at least two type of fuels. The combustor basket has got a circumferential wall comprising a plurality of openings. The combustion system further has a first conduit adapted to provide a first type of fuel directly to the combustor basket, a second conduit adapted to provide a second type of fuel directly to the combustor basket and a third conduit adapted to inject at least one of the first type of fuel and the second type of fuel through the openings into the combustor basket.

Abstract: A system when installed in-line with a pollution source provides reduction and/or complete combustion of harmful emissions generated there from. Such emissions including (but not limited to) compounds such as oxides of nitrogen, hydrocarbons, carbon monoxide, odors, organic and inorganic particulates. The pollution source can be of any type, such as smoke from a smokestack, engine exhaust, etc. The re-burner system is of very simple construction, is extremely energy efficient and does not require any moving parts or maintenance, respectively.

Abstract: Disclosed is a mixing hole arrangement for improving homogeneity of an air and fuel mixture in a combustor, the mixing hole arrangement comprising a plurality of mixing holes defined by a liner, wherein at least one of the plurality of mixing holes is a mixing hole that is at least one of sized and positioned to impede penetration of a fluid flow into a primary mixing zone located in a head end of the combustor.

Abstract: What are described are a multiple burner arrangement and a method for operating such a multiple burner arrangement with a multiplicity of individual burners which are designed as premix burners and which serve for firing a combustion chamber of a thermal engine and each have a swirl space into which combustion supply air and fuel can be introduced so as to form a swirl flow, the swirl flow forming downstream of the premix burner, within the combustion chamber, a backflow zone in which a burner flame is formed.

Abstract: Abatement systems are described. An abatement system includes a combustion chamber and a fuel burner ring coupled with the combustion chamber. Another abatement system includes a combustion chamber and a fuel flow control mechanism coupled with the combustion chamber.

Abstract: A flame tube for a liquid fuel burner is disclosed. The liquid fuel burner includes a fuel atomizer directing atomized fuel into the flame tube and an igniter disposed within the flame tube to ignite the atomized fuel. The flame tube comprises an outer wall and an inner wall disposed about the outer wall to define an air passage therebetween. At a discharge end of the flame tube, the outer and inner walls are conjoined to form an annular surface, the annular surface being perforated. Preferably, the annular surface is perforated in an evenly distributed pattern.

Abstract: A premix burner for producing an ignitable fuel/air mixture has a swirl generator with at least two burner shells (B) which complement one another to form a throughflow body, which in each case have a first burner shell section (1) with a partial cone shape and together enclose an axially conically widening swirl space and which mutually define, in the axial cone longitudinal direction, tangential air inlet slots (LS), through which the combustion feed air (L) passes into the swirl space, in which an axially spreading swirl flow forms, and includes fuel feeds which are arranged at least in sections along the tangentially running air inlet slots (LS).

Abstract: A method and device for improved efficiency in thermal oxidation is presented which uses a cyclonic flame to combust a stream of hydrocarbons drawn to the flame source by a pressure differential. The improved burner and method are particularly suited for combusting volatile organic compounds that are a derivative result of another waste management process mechanically attached to a thermal oxidizer. The improved burner is formed by configuring a burner basket into a conical shape with openings that allow a combustible gas to travel along the interior of the basket frame. The gas travels spirally within the basket frame as it is assisted by forced air and when ignited, creates a cyclonic flame effectively combusting material such as volatile organic compounds that are manipulated into contacting the flame.

Abstract: A device for igniting combustible means, especially solid combustibles such as wood, charcoal, and similar. The device includes a pressurized receptacle that is filled with a combustible medium, a spring-loaded actuating valve which selectively opens and closes a discharge port of the receptacle, preferably by applying pressure with a fingertip, and a top part that is joined to the discharge port and has a tubular extension having an adequate length.

Abstract: The invention relates to a burner comprising several substantially concentric channels, one (1) of which is arranged outside of all fuel supply conduits and is delimited by two pipes (2,3), whose axes (4) are placed in a parallel position and which are movable with respect to each other. According to said invention, diverting members (6) used for imparting a tangential component (7) to a fluid flowing in the channel (1) are carried by the first pipe (2) and are fixed thereto, the second pipe (3) comprises a drive portion (9) for driving the fluid outside the diverting members (6) and the angle of tangential deviation of the fluid at the downstream end (8) of the channel (1) depends on the axial position of the second pipe (3) with respect to the first pipe (2).

Abstract: A variable orifice combustor unit 10 comprises an annular combustion chamber 12 extending about a central axis 14 and ending in a discharge nozzle 16. Charging of the chamber 12 takes place from combustion fuel and air supply chambers 18 and 20 via a fuel charging orifice array 22 and an air charging orifice array 24. The orifices 28.1, 28.2 of the orifice arrays 22, 24 are positioned and slanted at the same forward angle in the direction of the nozzle 16 to the effect of their central axes 38, 40 cutting along the longitudinal centre of the combustion chamber 12. The cross sectional sizes of the orifices 28 are adjustable by means of an orificed displaceably mounted cyndrically shaped covering body 44 for the fuel charging side and an orificed cylindrical body 58 for the air charging side both being displaceable in the direction of the axis 12.

Abstract: A combustor comprises in flow series a burner, a transition piece and a combustion chamber being of larger diameter than the transition piece, the combustion chamber being connected to the transition piece via a dome portion. In the dome portion are located air injection openings. A method of operating the combustor comprises the stop of introducing air from the dome portion by means of air jets.

Abstract: A lean premixed, radial inflow, multi-annular staged nozzle for creating three independent combustion zones within a can-annular, dual-fuel gas turbine combustor is provided. The nozzle includes a pilot zone fueled by a gas pilot nozzle and center cartridge; a flame holder zone fueled by an inner main gas fuel; a main flame zone fueled by an outer main gas fuel; a main radial swirler for mixing a portion of incoming air to the nozzle with the inner main gas fuel supply and the outer main gas fuel supply; an endcover; and means for controlling the ratio of an inner main gas fuel supplied and an outer main gas fuel supplied.

Abstract: The present invention includes an integrated fuel processor subsystem incorporating a thermal combustor, a catalytic combustor, a quasi-autothermal reactor (QATR) and a air-fuel-steam (AFS) mixer to provide a range of operating modes exhibiting performance between that of a pure steam reformer and a pure autothermal reformer to increase the flexibility of the fuel processor to handle transient system demands such as cold starts, suppress emissions and carbon formation and improve efficiency.

Abstract: A premix burner for a heat generator has partial cone shells (5) which make up a vortex generator, and which encompass a conically widening vortex chamber (6) and mutually define tangential air inlet slots (7), and also with feeds for gaseous and/or liquid fuel, of which at least one is arranged along the air inlet slots (7) on the partial cone shells (5), and at least one other is arranged along a burner axis (A) which centrally passes through the vortex chamber (6). At least n partial cone shells (5) encompass the vortex chamber (6), and define n air inlet slots (7), with n?3, preferably n?5, the n air inlet slots (7) each have at least a maximum slot width (10) which is equal to or larger than that slot width (10) which a generic type premix burner (1) of the same size and dimensioning with m?2 partial cone shells (5) and m air inlet slots (7) has.

Abstract: A burner apparatus for an indoor or outdoor fireplace, fire pit, stove or oven is shown. The burner apparatus operates to produce natural gas fueled or liquid petroleum fueled amber flames among artificial logs, coals or a combination of artificial logs and coals, simulating a natural fire. One embodiment of the burner apparatus comprises a burner tube loop for the distribution of fuel, a fuel/air mixing valve for mixing the fuel and air before ignition of the resulting fuel/air mixture, metal cups for the dissipation of the fuel/air mixture and flames, an ignition system for igniting the fuel/air mixture, a control system for monitoring and controlling the ignition of the fuel and for regulating the flow of fuel, and artificial logs, coals or a combination of logs and coals placed around the burner tube loop to provide for an aesthetically pleasing and natural looking display.

Abstract: A burner assembly for a gas powered cooking appliance is provided. The burner assembly may include a burner body including a central region and a plurality of radiating extensions extending radially outward from the central region. The burner assembly may include a burner cap with a central region and a plurality of radiating extensions extending radially outward from the central region. The burner cap is positioned on top of the burner body when the burner is assembled. The burner cap may include at least one overhang positioned on the outer perimeter of the central region and between an adjacent pair of radiating extensions. The at least one overhang forms a gap between the exterior wall of the burner body and the interior wall of the overhang. This gap, or flame stabilization chamber, provides for collection of gases and flame that aid in maintaining the flame during low temperature operation.

Abstract: A direct-air, gas-fired air makeup heating unit is disclosed which provides reduced nitrogen dioxide emissions with a higher temperature rise. The unit includes a combustion chamber with a protective chamber downstream of the combustion chamber. At high firing intensity, the flame exits the combustion chamber and enters the protective chamber. The resulting flame is therefore protected from excess air moving around the combustion chamber, thereby lowering nitrogen dioxide emissions even at such high firing intensities.

Abstract: A combustion apparatus comprising a pre-combustor stage and a primary combustion stage, the pre-combustor stage having two co-axial cylinders, one for oxidant and one for fuel gas, in which the fuel gas is preheated and the primary combustion stage having rectangular co-axial passages through which fuel and oxidant are admitted into a refractory burner block. Both passages converge in the vertical plane and diverge in the horizontal plane. The passage through the refractory burner block also has a rectangular profile and diverges in the horizontal plane. The outlets to the primary combustion stage are recessed in the refractory burner block at a distance which may be varied.

Abstract: A burner apparatus comprising housing defining a chamber and having an air inlet, a peripherally extending baffle disposed in the housing, a first peripherally extending flow passage being formed between the housing and the baffle, the first flow passage being in open communication with the air inlet, a peripherally extending combustion liner disposed inwardly of the baffle, a second peripherally extending flow passage being formed between the liner and the baffle, the second flow passage being in open communication with the first passage, a reversing diverter disposed in the chamber and positioned to direct air flowing from the first flow passage into the second flow passage, a burner assembly mounting plate disposed in the liner and having a first side and a second side, the mounting plate and the liner at least partially defining a burner barrel on the first side of the mounting plate, at least one burner assembly mounted on the burner mounting plate and a plenum on the second side of the mounting plate th

Abstract: A combustion system for a portable forced air heater having two frusta-conical sections attached to a circular burner tube, wherein each frusta-conical section has pre-determined vent hole patterns that allow the gas heater to have a variable burn rate.

Abstract: A continuously operating ultra-stable flare pilot for igniting a flammable fluid discharged from the open end of a flare stack and methods are provided. The flare pilot basically comprises a fuel-air mixture inlet conduit, a fuel-air mixture discharge nozzle attached to the fuel-air mixture inlet conduit and a wind shield having a lower end attached to the fuel-air mixture discharge nozzle or the fuel-air mixture inlet conduit. The wind shield has an open upper end which includes an upstanding wall portion facing the open end of the flare stack and the wind shield includes an outwardly extending wind capturing baffle attached to each of the opposite sides of the wind shield positioned substantially around openings in the wind shield through which captured wind can flow into the interior of the wind shield.

Abstract: A direct gas-fired burner assembly is disclosed in which a two-stage flame is produced. A gas manifold is attached to two baffles with apertures disposed therein. The apertures are designed such that a fuel rich zone occurs near the manifold, while a lean zone occurs away from the manifold. At high fire, the apertures create a negative pressure zone which draws the gas away from the burner thereby allowing a primary flame to burn. The primary flame in the fuel rich zone ignites a secondary flame in the lean zone. Because a flame is burning throughout the entire combustion zone, the flame does not move out past the baffles, the flame remains smaller and cooler, and a lower output of pollutants is achieved.

Abstract: A gas generator S of the present invention comprises an elongated cylindrical housing 1 closed at both ends thereof, a combustion chamber 2, formed in the housing 1 at one end portion thereof, for packing gas generant 3 that is burnt to generate high temperature gas, an igniter device 5, fixed in the housing 1 at one end thereof, for igniting and burning the gas generant 3 packed in the combustion chamber 2, a filtering member 4, inserted in the housing 1 and set at the other end portion of the housing 1, and gas discharge holes 6 formed at the other end of the housing 1 to communicate between an inside of the housing 1 and an outside of the same with respect to an axial direction of the housing 1.

Abstract: A continuously operating ultra-stable flare pilot for igniting a flammable fluid discharged from the open end of a flare stack and methods are provided. The flare pilot basically comprises a fuel-air mixture inlet conduit, a fuel-air mixture discharge nozzle attached to the fuel-air mixture inlet conduit and a wind shield having a lower end attached to the fuel-air mixture discharge nozzle or the fuel-air mixture inlet conduit. The wind shield has an open upper end which includes an upstanding wall portion facing the open end of the flare stack and the wind shield includes an outwardly extending wind capturing baffle attached to each of the opposite sides of the wind shield positioned substantially around openings in the wind shield through which captured wind can flow into the interior of the wind shield.

Abstract: A combustion system for a portable forced air heater having two frusta-conical sections attached to a circular burner tube, wherein each frusta-conical section has pre-determined vent hole patterns that allow the gas heater to have a variable burn rate.

Abstract: An industrial burner assembly comprising a manifold with a fuel inlet and a longitudinal axis, and a plurality of elongated burners positioned radially about the longitudinal axis having fuel ports in communication with the manifold and fuel inlet, wherein each elongated burner has an outer mixing tube, an inner mixing tube positioned coaxially within the outer mixing tube to form an annular space therebetween in communication with the fuel port, the inner mixing tube having an inner surface forming a passage for air flow through the burner assembly, and a plurality of apertures formed in the inner mixing tube to allow introduction of fuel from the annular space into the air flow passage to provide for efficient mixture of air and fuel in the burner assembly prior to combustion.

Abstract: A device for incinerating waste gases has a combustion chamber, burner for burning waste gas in the combustion chamber, and a tubular conduit extending substantially vertically from the combustion chamber so that products of combustion of the waste gas in the combustion chamber travel vertically upwardly through the tubular conduit, the tubular conduit being composed of a plurality of tubular elements located one above the other and arranged relative to one another so as to form a gap between each two neighboring tubular elements for introducing air into an interior of the tubular conduit through the gaps.

Abstract: A waste and toxic gas reactor for completely combusting produced gases with low NOx emissions is provided. The reactor includes a plurality of staged air orifices that create a vortex in the combustion chamber. The vortex increases the residence time of the introduced gas molecules and thus facilitates complete combustion at lower temperatures.

Abstract: A combustor having a combustion liner and at least one combustor orifice assembly, the combustor orifice assembly comprising a boss, an orifice plate that defines an orifice, the orifice plate having a bottom surface that is adapted to be received by the boss, and a retaining ring, whereby the orifice plate is retained between the retaining ring and the boss.

Abstract: An air heating burner having improved CO emissions across a broad range of heat inputs. The burner incorporates wings which cover portions of mixing plates associated with low to medium-low fire. The wings reduce air flow velocity to eliminate quenching during such conditions, thereby increasing combustion temperature and reducing CO emissions. The wings also form pre-heat chambers which further increase combustion temperature. The burner produces a substantially consistent level of CO emissions across the range of inputs, regardless of the pressure drop across the burner.

Abstract: Dilution sleeves are provided in radially aligned openings in the combustion liner and flow sleeve of a combustor for a gas turbine. The sleeves have a flange for seating on a collar of the flow sleeve about the opening therethrough enabling the dilution sleeve to extend through the aligned openings. A cover is removably mounted on the outer casing and a spring bears between the cover and the dilution sleeve flange to maintain the dilution sleeve in the openings. Dilution sleeves having different cross-sectional flow areas may be provided in lieu of initially installed dilution sleeves upon comparing measured emission levels with desired emission levels and ascertaining the desired increase or decrease in cross-sectional flow area through the dilution sleeves.

Abstract: A combustor having a combustion liner and at least one combustor orifice assembly, the combustor orifice assembly comprising a boss, an orifice plate that defines an orifice, the orifice plate having a bottom surface that is adapted to be received by the boss, and a retaining ring, whereby the orifice plate is retained between the retaining ring and the boss.

Abstract: There exists a tendency in the construction of combustion devices to employ a multi-level, spatially distributed feed of the combustion air in order to be able to better influence the stoichiometric ratios during the combustion. These solutions are little suited for the compact construction and, in addition, the flame temperature is too high in the region of the air feed relative to a low NOx combustion if one does not employ expensive constructions with additional cooling bodies.

Abstract: A three-stage lean burn combustion chamber (28) comprises a primary combustion zone (36), a secondary combustion zone (40) and a tertiary combustion zone (44). Each of the combustion zones (36,40,44) is supplied with premixed fuel and air by respective fuel and air mixing ducts (54,70,92). The fuel and air mixing ducts (54,70,92) have a plurality of air injections apertures (62,64,76,98) spaced apart in the direction of flow through the fuel and air mixing ducts (54,70,92). The apertures (62,64,76,98) reduce the magnitude of the fluctuations in the fuel to air ratio of the fuel and air mixture supplied into the at least one combustion zone (36,40,44). This reduces the generation of harmful vibrations in the combustion chamber (28).

Abstract: An improved gas burner comprising in combination means for controlled feeding and subsequent admixing of a secondary air directly to the base of the flame in a form of a cap coaxially surrounding a burner head of the gas burner comprising a lateral apertures for issuing combustible air-gas mixture to form a flame. The through lateral openings of the predetermined size having the total cross section greater than the total cross-section of the apertures of burner head are performed on the side wall surface of the cap. During the operation of the gas burner the exact measured amount of the secondary air is admixed directly to the base of the flame, thereby highly efficient and complete combustion process characterized by high-elevated temperature is achieved.

Abstract: A high efficiency, Vortex Inertial Staged Air (VIStA) combustor provides ultra-low NO.sub.X production of about 20 ppmvd or less with CO emissions of less than 50 ppmvd, both at 3% O.sub.2. Prompt NO.sub.X production is reduced by partially reforming the fuel in a first combustion stage to CO and H.sub.2. This is achieved in the first stage by operating with a fuel rich mixture, and by recirculating partially oxidized combustion products, with control over stoichiometry, recirculation rate and residence time. Thermal NO.sub.X production is reduced in the first stage by reducing the occurrence of high temperature combustion gas regions. This is achieved by providing the first stage burner with a thoroughly pre-mixed fuel/oxidant composition, and by recirculating part of the combustion products to further mix the gases and provide a more uniform temperature in the first stage. In a second stage combustor thermal NO.sub.

Abstract: A heat shield configuration, particularly for protecting supporting structures and structural parts of gas turbine plants against a hot fluid. The heat shield has an inner lining which consists of a heat-resistant material and which is composed of plate-shaped heat-shield elements resistant to high temperatures and are disposed next to one another with gaps in-between. The heat-shield elements cover the entire area of the structural part. The heat shield is anchored so as to be thermally movable to the supporting structures and parts by bolts. The heat-shield element is formed of an erosion-proof and corrosion-proof material. An insulating brick formed of a refractory ceramic is disposed in each case between each heat-shield element and the supporting structure or parts.

Abstract: A combustion chamber of a burner for a vehicle heater or for thermal regeneration of an exhaust gas particle filter having a frontal boundary wall, a circumferential boundary wall, a connector for fitting a glow plug and a connector for conveying combustion air which projects from the frontal boundary wall into the combustion chamber and has at least combustion air outlets through the connector wall, in which the combustion chamber with the frontal boundary wall, the circumferential boundary wall, the glow plug connector and with or without the air supply connector takes the form of a one-piece precision-cast component.

Abstract: A burner arrangement for ferrous scrap melting and the like includes a fuel outlet and a primary oxidant supply outlet communicating with a mixing chamber. The burner also has a main outlet and secondary oxidant supply outlets. In addition there is a convergent-divergent nozzle communicating with the mixing chamber. Valves control the flow of gaseous fuel to the fuel outlet, and the flow of primary and secondary oxidant to the primary and secondary oxidant supply outlets. In operation, oxidant is supplied to the primary and secondary outlets, hot flame or combustion gases are accelerated through the nozzle with the result that a sonic or supersonic velocity can be created. Such high velocities facilitate the penetration of the combustion gases through a slag layer into molten metal.

Abstract: In a burner for operating a combustion chamber with a liquid and/or gaseous fuel (12, 16), the combustion air (7) required for this purpose is directed through tangential air-inlet ducts (5, 6) into an interior space of the burner. This directing of the flow results in a swirl flow in the interior space, which swirl flow induces a backflow zone at the outlet of the burner. In order to stabilize the flame front forming there, at least one zone (27) is provided at each sectional body (1, 2) forming the burner, within which zone (27) inlet openings (29) are provided for the injection of supplementary air (32) into the swirl flow (7a). Due to this injection, a film forms at the inner wall of the sectional bodies (1, 2), which film prevents the flame from being able to flashback along the inner wall of the sectional bodies (1, 2) into the interior space of the burner.

Abstract: In a premix burner (18) having axial or radial air inflow, in which premix burner (18) the combustion air (15) flows out of a plenum (27), arranged before or around the burner (18), into the burner (18) and fuel (12, 13) is mixed with it on the way through the burner (18), a perforated component (24) having a wall thickness (s) and openings (25) of in each case a diameter (d) and at a distance (t) apart is arranged between the plenum (27) and the burner (18), which component (24) splits the combustion air (15) flowing through into small defined jets which reunite after a certain running length (l), the ratio of wall thickness (s) to the diameter (d) of the openings (25) being greater than/equal to one, and the ratio between the through-flow area of the component (24) and the possible inflow area to the burner (18) being greater than/equal to one as a function of the type of burner.

Abstract: A combustor for a gas turbine engine having a porous outer metallic shell and a thin-walled, nonporous ceramic liner whose backside is impingement cooled, with only primary and secondary openings in the ceramic liner for delivering pressurized primary air and dilution air to the combustion zone.

Abstract: A flare burner comprises a stack conduit, a plurality of gas distributing conduit extending radially from the stack conduit, and a plurality of gas supersonic gas nozzles connected to the gas distributing conduit. The stack conduit supplies flare gas to each of the gas distributing conduits, with gas communication therebetween. In one embodiment, the nozzles are directly connected to gas distributing conduit and in another embodiment the nozzles are connected to the gas distributing conduits via vertically extending burner conduits. The gas discharged through the supersonic nozzle flows at a supersonic velocity. The length of the burner conduits attached to the same gas distributing conduit becomes progressively shorter as the burner conduits are positioned further away from the stack conduit.

Abstract: A fuel-fired, forced air, draft induced heating furnace is provided with NOx reduction apparatus associated with a plurality of combustor tubes forming a portion of its heat exchanger structure. In-shot type fuel burners are spaced apart from and face the open inlet ends of horizontal combustion sections of the combustor tubes. The NOx reduction apparatus includes a plurality of metal mesh tubes having diameters substantially less than the internal diameters of the combustion tubes. Each metal mesh tube is coaxially anchored to and telescopingly over the outlet end of one of the burners and extends therefrom coaxially into the associated combustion tube.

Abstract: In a cooled wall part having a plurality of separate convectively cooled longitudinally cooling ducts (2) running near the inner wall (1) and parallel thereto, adjacent longitudinal cooling ducts (2) being connected to one another in each case via intermediate ribs (3), there is provided at the downstream end of the longitudinal cooling ducts (2) a deflecting device (4) which is connected to at least one backflow cooling duct (6) which is arranged near the outer wall (5) in the wall part and from which a plurality of tubelets (7) extending to the inner wall (1) of the cooled wall part and arranged in the intermediate ribs (3) branch off. By means of this wall part, the cooling medium can be put to multiple use for cooling (convective, effusion, film cooling).

Abstract: A nozzle adapted for use in a high excess air burner. The nozzle includes three combustion chambers and an outer flame retention ring for supporting combustion of gaseous fuel over a range of volumetric flow rates. Combustion air is staged to each of the combustion chambers and to the outer flame retention ring for mixing with the fuel to form a combustible fuel-air mixture. Combustion occurs in the first combustion chamber at relatively low flow rates of fuel. Combustion occurs in the second and third combustion chambers and the outer flame retention ring with increasingly higher fuel flow rates. The second combustion chamber is configured with a radially inwardly converging sidewall to provide for a smooth transition of the flame between the second and third combustion chambers.

Abstract: An ignition device including a housing, which is formed of an upper shell, a bottom shell, and a partition plate longitudinally connected between the upper shell and the bottom shell; a gas release device mounted within the housing and controlled to release a fuel gas for burning; a sliding control key device mounted on the housing and controlled to drive the gas release device, causing the gas release device to release the fuel gas, and to produce static sparks for burning the fuel gas; and a fan device mounted within an upright endless wall on the partition plate between the upper shell and the bottom shell and controlled by the sliding control key device to draw a flow of air into the housing, permitting the flow of air to be further guided out of the housing for accelerating the burning of the article been burnt by the ignition device.

Abstract: A pressurized space heater for burning gaseous fuel has as its main component a generally conical burner tube that receives at its narrow end a combustible mixture of fuel and primary air. Complete combustion in the tube is enhanced by two sets of holes disposed along the tube for admitting secondary air. The location, number and sizes of the holes are so chosen as to ensure complete combustion and to avoid the production of noxious substances.

Abstract: The pressure head needed to drive combustion air into the combustion region (46) of a heat gun (930) is imparted to the air by a compressor blades (36) driven by a turbine whose blades (32) are interposed in the fuel conduit that leads to the combustion region (46). The expansion of the gaseous fuel, which is obtained from a pressurized source, provides the power to impose the necessary pressure head. The turbine-compressor combination is efficient enough that it can extract from the fuel flow enough power to maintain the necessary pressure head not only on the combustion gas (A.sub.1), which flows through vents (44) in a manifold (43), but also on a larger volume of air (A.sub.2) delivered downstream of the combustion region (46) to dilute the combustion products and thereby cool them to the desired heat-gun output temperature.