MXPA99010280A - Low-emissions industrial burner - Google Patents

Abstract

A burner (10) for use in both high O2 environments and low O2 environments comprises an outer tube (24) and an inner tube (26). The outer tube (24) defines a flow passage (53) and includes an inlet portion (42), an outlet portion (46), and a nozzle portion (44) interconnecting the inlet portion (42) and outlet portion (46). The inlet portion (42) has a larger effective cross-sectional area than the outlet portion (46) so that air (20) or an air-and-fuel mixture (35) moving through nozzle portion (44) is accelerated. The inner tube (26) is positioned to lie in the flow passage (53) of the outer tube (24) and is formed to include fuel-injection holes (78) to conduct fuel (33) into the flow passage (53).

Description

INDUSTRIAL BURNER OF LOW EMISSIONS Field of the Invention The present invention relates to burner assemblies, and particularly, to an industrial burner of low emissions. More particularly, the present invention relates to an industrial burner of low emissions to burn a fuel mixture to produce a flame.

Background and Brief Description of the Invention Another challenge facing the burner industry is to design a burner with minimal parts that produces low nitrogen oxide emissions (N0X) during operation. Typically, a mixture of gaseous fuel and either air or oxygen in the proper ratio is created in an industrial burner to produce a combustible mixture of air and a combustible substance. The mixture is then ignited and burned to produce a flame that can be used to heat several products in a wide variety of applications. However, when the fuel and Ref.032009 air are not completely mixed or mixed in an appropriate ratio, the combustion of the fuel such as natural gas, petroleum, liquid propane gas, low BTU gases, and pulverized coals often produce high levels of several undesirable polluting emissions such as nitrogen oxide (N0X), carbon monoxide (CO), and total hydrocarbons (THC). In accordance with the present invention, a burner is provided having an outer tube defining a flow passage and an inner tube which is positioned to abut the flow passage. The outer tube includes an inlet portion having a large diameter, an outlet portion having a small diameter that is smaller than the large diameter of the inlet portion, and a nozzle portion interconnecting the inlet and outlet portions. . The inlet portion of the outer tube is adapted to be coupled to an air supply to drive air through the flow passage. The inner tube includes an inlet end that is adapted to be coupled to a fuel supply and is shaped to include at least one hole for fuel injection to drive the fuel from the fuel supply to the flow passage to establish a mixes fuel from the air and the combustible substance inside the flow passage. In a preferred embodiment, the burner is coupled to a long refractory block. The long refractory block extends beyond the outlet end of the burner and creates a flame chamber within the refractory block to contain the flame. The fuel injection orifices formed in the inner tube are preferably located in the outlet portion of the outer tube. However, the fuel injection orifices can also be placed in the nozzle portion or the inlet portion of the outer tube and / or a mixture of air and fuel can be supplied at the inlet end of the burner. In a second embodiment, a burner is coupled to a short refractory block. The short refractory block terminates prior to the outlet end of the burner so that the outlet end of the burner extends beyond the refractory block. This allows a mixture of air and fuel discharged from an outlet end of the burner to mix with the recycled oven gas contained in a furnace chamber in which the flame burns because the flame is not contained within a chamber. for the flame defined by the refractory block.

The additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as it is currently perceived.

Brief Description of the Drawings The detailed description pertains particularly to the appended Figures in which: Figure 1 is a side elevation view of a burner assembly including a burner according to a first embodiment of the present invention, with portions removed by cutting , which shows a supply of fuel and an air supply coupled to an inlet end of the burner and a long refractory block coupled to an outlet end of the burner and formed to include a chamber to contain a flame produced by the burner, the burner it includes an external tube carrying a swirling plate which conveys the air discharged from the air supply and swirled by the stirring plate through a section of the nozzle towards the flame chamber , an inner tube coupled to the fuel supply and configured to discharge the fuel in an accelerated air stream in the outer tube to create a combustible mixture of air and the combustible substance therein, a flame retainer with a flattened wide front body coupled to a downstream end of the inner tube, and a lighter coupled to the outer tube to ignite the combustible air mixture and the combustible substance therein; Figure 2 is a view of the burner assembly taken along lines 2-2 of Figure 1 through the outer tube at a location downstream of the swirling stir plate showing the internal fuel pipe which extends through the external air tube; Figure 3 is a front perspective view of the burner of Figure 1 showing the flared wide front body flame retainer placed in the flame chamber formed in the refractory block; Figure 4 is a perspective view of the inner tube of Figure 1 showing the crushed wide-faced body flare retainer coupled to the downstream end of the inner tube and the fuel injection orifices formed in a portion of the inner tube located upstream of the flared wide front body flare retainer; Figure 5 is a rear perspective view of the burner of Figure 1 showing the swirling plate attached to an air inlet section of the burner to swirl the flow of air through the burner and showing a fuel supply pipe extending perpendicularly through the external pipe in the burner air inlet section; Figure 6 is a side elevation view of a burner similar to the burner of Figure 1, showing the placement of fuel injection ports in an inner tube at a location that remains downstream from the location shown in Figure 1 and closer to the crushed wide front body flare retainer for discharging the fuel in a region immediately upstream of the flared wide front body flare retainer; Figure 6A is a perspective view of the inner tube of Figure 6 showing the flattened wide front body flare retainer coupled to the downstream end of the inner tube and the fuel injection ports in a portion of the inner located tube immediately upstream of the flared wide front body flare retainer; Figure 7 is a side elevational view of a burner similar to the burner of Figure 6, showing the placement of the fuel injection ports in an inner tube at a location that rests upstream of the location shown in the Figure 6 and closest to the swirling stir plate to discharge the fuel to a region immediately downstream of the agitator; Figure 7A is a perspective view of the inner tube of Figure 7 showing the crushed wide-faced body flare retainer coupled to the downstream end of the inner tube and the holes for fuel injection formed in a portion of the tube internally located at the upstream end of the inner tube; Figure 8 is a side elevation view of a burner similar to the burners of Figures 1-7 according to another embodiment of the present invention showing the admission of a premixed air and fuel mixture to the inlet end of the burner without the supply of fuel coupled to the inner tube; Figure 9 is a side elevational view of a burner similar to the burner of Figure 8 according to yet another embodiment of the present invention showing the admission of a premixed air and fuel mixture to the inlet end of the burner in combination with a fuel supply coupled to the inner tube to allow fuel from the fuel supply to be discharged through the fuel injection orifices formed in the inner tube and combined with the mixture of air and fuel admitted through the end of the tube. burner inlet; Figure 10 is a side elevational view of a burner similar to the burners of Figures 1-9 according to yet another embodiment of the present invention showing injection of the fuel through a fuel supply manifold mounted in the burner inlet end; Figure 10A is a perspective view of the burner of Figure 10 showing the passage of the fuel to the external tube of the burner through the tubular spokes spaced apart circumferentially included in the fuel supply manifold in the form of a wagon wheel; Figure 11 is a perspective view of a burner according to a further embodiment of the present invention showing a passageway for receiving air having a somewhat rectangular cross section; Figure 11A is a perspective view of a line burner according to a further embodiment of the invention showing three burners of the type shown in Figure 11 arranged in sequence to define a burner assembly of the line; Figure 12 is a perspective view of a burner similar to the burner in Figures 1-5, with portions removed by cutting, showing an internal fuel supply tube configured to discharge fuel from a primary fuel supply through the fuel injection holes formed in the inner tube and a pair of concentric tubes extending through the inlet end of the burner and into the inner tube and ending in the flame retainer, an outer tube of the concentric tubes which is configured to discharge oxygen from an oxygen supply at an outlet end of the burner and an inner tube from the concentric tubes that is configured to discharge the fuel from a secondary fuel supply at an outlet end of the burner flame; Figure 13 is a perspective view of a burner similar to the burner in Figures 1-5, with portions removed by cutting, showing an internal fuel supply pipe, configured to discharge the fuel from a primary fuel supply through of the holes for fuel injection formed in the inner tube and a single tube extending through the inlet end of the burner towards the inner tube and ending in the crushed wide front body flare retainer to discharge the waste gas from a waste gas supply at an outlet end of the burner flame; Figure 14 is a side elevational view of a burner assembly similar to the burner assembly of Figures 1-5 showing the burner of Figures 1-5 being coupled to a furnace chamber using a short refractory block so that a mixture of air and fuel discharged from an outlet end of the burner is mixed with the recycled kiln gases (the products of combustion) contained in the furnace chamber; Figure 15 is an exploded side elevational view of the burner assembly of Figure 14, showing the burner of Figure 14 in greater detail; and Figure 16 is a side elevation view of a burner assembly similar to the burner assembly of Figure 15, showing the burner without a cyclonizer.

Detailed Description of the Drawings A burner according to the present invention is very suitable for use in environments or processes of high levels of oxygen such as thermal oxidizers, smoke incinerators, and afterburners for burning pollutants wherein the concentration of oxygen (02) in the Process chamber is greater than twelve percent (typically seventeen to nineteen percent oxygen). The present burner is very suitable for use in environments or processes of low oxygen levels such as boilers, ovens, stoves, and rotary dryers where the concentration of oxygen in the process chamber is less than or equal to twelve percent (typically less than six percent). The burner 10 can also be used, for example, to incinerate industrial fumes, to heat water, or to generate steam. A burner assembly 11 including a burner 10 in accordance with the present invention is illustrated in Figure 1. The burner 10 operates in conjunction with an air supply 12, a fuel supply 14, and a refractory block 16 to produce a flare 18 of low emissions within a flame chamber 19 formed in the refractory block 16. The burner 10 includes an outer tube 24, an inner tube 26, a cyclonizer 28, a lighter 30, and a body flame arrestor wide-front crushed _ 32. When used here, "pipe" means any conduit or channel, regardless of the shape (ie, the cylindrical cross-section, the rectangular cross-section or otherwise), through the which some substance (such as a liquid, solid, or gas) is transported or driven. The cyclonizer 28 is positioned to rest on an inlet end 36 of the air of the burner 10 and the flame retainer 32 is positioned to lie at an outlet end 38 of the flame of the burner 10. The inner and outer tubes 26, 24 and the flame retainer 32 are preferably made of heat-resistant alloys. For example, the inner and outer tubes 26, 24 are preferably made of 18-8 stainless steel, and a flattened wide front body flare retainer 32 is made of 310 stainless steel. In use, air 20 is introduced. on a central line 82 of the burner 10 towards a rear portion of the burner 10 and directed to pass over the cyclonizer 28, which provides stability when excess air is present, and is mixed with gaseous fuel 33, which is injected perpendicularly to the air stream 20. A combustible premix of the air and combustible substance 35 is thus established, which flows through a smooth flow passageway 73 and passes over the crushed wide front body flare retainer 32, where the Premix 35 is burned within the refractory block 16 (or, for example, a metal sleeve) to produce the flame 18. The burner assembly 11 uses the refractory block 16 as a combustion chamber. ion in conjunction with a fuel and air premixing apparatus which operates to pre-mix the air 20 and the fuel 33 partially prior to ignition while the air 20 is forced through the burner 10 by a fan (not shown) coupled to the air supply 12. A lighter 30 is positioned to communicate with the premix of the air and fuel 35 at a point in the burner 10 upstream of the flame fixing area. In the burner 10, the possibility of fixing the nearest flame is minimized because: (1) the mixture of air and fuel 35 is moved at a speed that exceeds the speed of the flame and (2) the passageway Flow 75 is relatively smooth to minimize possible turbulence. Although the burner of the present invention includes both of these characteristics, either alone (as well as other features) could be used to effect the same result. For example, even if a burner does not have a "smooth" flow passage, the mixture could be moved at a sufficiently high speed to avoid fixing the closest flame. Similarly, an extremely smooth flow passageway could be used even at slower mixing speeds as long as the nearest flame fixation is avoided. Accordingly, although both features are present in the present preferred embodiment, it is within the scope of the present invention to minimize the possibility of fixing the closest flame using any feature independently or other similar characteristics. As shown in Figure 1, in the preferred embodiment the burner 10 has four sections. An air intake section (or inlet portion) 42, an air acceleration section (or nozzle portion) 44, a mixing / ignition section (or exit portion) 46, and a flame retention section 48. The outer tube 24 is shaped and configured to define the sections 42, 44 and 46. The crushed wide front body flare retainer 32 is positioned to be disposed adjacent one end of the outer tube 24 to define the section 48. An air intake section 42 of the burner 10 is defined by a cylindrical portion of the outer tube 24 located at an inlet end of the air 36 of the burner 10 as shown, for example, in Figure 1. This inlet portion 42 of the outer tube 24 has a relatively large internal diameter 52 and defines a low speed passageway 54 which conducts the swirling air 20 discharged from an air supply 12 and is passed through a cyclonizer 28 in u in the downstream direction 43 towards the air acceleration section (or nozzle portion) 44. The air 20 passing through the large diameter passageway 54 in the air intake section 42 travels in the downstream direction 43 to a relatively low speed, whereby the fall of the air pressure through the cyclonizer 28 is minimized. Preferably, the air 20 travels at a speed approximately equal to 1524 cm / sec. (50 ft / sec.) Inside the air intake section 42 which leads to a pressure drop of approximately 12.70 kg / m2 (0.5 inches of water) of water (column) through the cyclonizer 28. A plug 83 for the air pressure is coupled to the external tube 24 and configured to detect the air pressure 20 in the passageway 54. By locating the cyclonizer 28 in a low velocity environment away from the lighter 30 and the refractory block 16, the cyclonizer 28 is Less likely to be damaged by heat or high-speed pressures and therefore likely to last longer. An air acceleration section 44 of the burner 10 is defined by a conical portion of the outer tube 24 located between the air inlet end 36 and the flame exit end 38 of the burner 10 as shown, for example, in FIG. Figure 1. The conical portion (or nozzle) 44 has an internal diameter 52 at its inlet end 62, a relatively smaller internal diameter 70 at its outlet end '66, and a nozzle-shaped passageway 65 that converges at the downstream direction 43. The nozzle-shaped passageway 65 functions in a manner similar to a nozzle to accelerate the flow rate of air 20 flowing from the air intake section 42 through the air acceleration section 44 toward the exit end of the flare 38 of the burner 10. When the cyclonizer 28 is mounted in the chamber 54 of the air intake section 42, then the air 20 passing through a nozzle-shaped passageway at 65 it is agitated in a swirling manner while accelerating. The mixing / firing section (or exit portion) 46 of the burner 10 is defined by a cylindrical portion of the outer tube 24 located at an outlet end 38 of the burner flame 10 as shown, for example, in Figure 1. The cylindrical outlet portion 46 of the outer tube 24 has a smaller internal diameter 70 and leads to the swirling air 20 accelerated, discharged from an air acceleration section 44 at an additional high speed along a downstream direction 43 towards the flame chamber 19 in the refractory body 16. The inner tube 26 is configured to discharge the fuel 33 towards the swirling air as an accelerated swirl 20 passing through the portion cylindrical 46 of the outer tube 24 so that a combustible mixture of the air and the combustible substance 35 moves at a high speed once the lighter 30"has been passed into the flame chamber 19.

The inner tube 26 is positioned to lie in an outer tube 24 as shown, for example, in Figure 1 and is formed to include the constant outer diameter 71. An upstream end 25 of the inner tube 26 is coupled to the fuel supply 14 by a fuel supply line 27 and a downstream end 29 of the inner tube 26 is configured to support the crushed wide front body flare retainer 32 in the flame chamber 19 of the refractory block 16 in a spaced relation far with respect to the downstream end 31 of the cylindrical portion 46 of the outer tube 24. The fuel supply line 27 includes an elbow-shaped pipe 58, coupled to the upstream end 25 of the inner tube 26 and a supply pipe 56 coupled to the elbow-shaped pipe 58 and to the fuel supply 14. A supply pipe 56 passes through an opening 57 formed in a side wall d the outer tube 24 as shown, for example, in Figures 1-4. A pilot inlet pipe 81 is attached to the supply pipe 56 as shown, for example, in Figures 1-14. The inner tube 26 is configured to conduct the fuel 33 received from the fuel supply line 27 through a passageway 77 formed therein as shown, for example, in Figure 4 and then discharge the fuel 33 into the tube. outer 24 so that it mixes with the swirling air 20 driven through the cylindrical portion 46 of the outer tube 24 to form a combustible mixture of air and the combustible substance traveling in a downstream direction. through a high-speed passageway 73 defined by the inner and outer tubes 26, 24 towards the crushed wide front body flame retainer 32 and the flame chamber 19 in the refractory body 16. In a preferred embodiment, the high-speed passageway 73 is annular and surrounds a cylindrical outer surface 39 of the inner tube 26 and is joined by a cylindrical inner surface 37 of the external tube 36 which is positioned to to surround the inner tube 26. The air 20 has been accelerated to a maximum velocity at the outlet end 66 of the air acceleration section 44 and then is introduced to the inlet end 74 of the high-speed passageway 73 provided in a section of mixing / ignition 46. The air 20 continues to flow and swirl in a swirling manner through the mixing / ignition section 44 at a constant speed because the internal diameter 70 of the high-speed passage 73 remains constant throughout of the length of the mixing / firing section 46. The distance between the inner tube 26 and the outer tube 24 within the mixing / firing section 46 is shown as the constant radial gap 72 defining the annular high-speed passageway. in the mixing / ignition section 46. The axial air velocity through the mixing / ignition section 44 must be slow enough to allow complete mixing of the fuel and the fuel. ire, but fast enough to prevent the closest flame from attaching (ie, fixing the flame upstream of the flame retainer). For example, the air speed of 7620 cm / sec. (250 ft / second) it has been found that it will be slow enough to supplement mixing but fast enough to avoid fixing the closest flame for burners that have a 15: 1 waste ratio. The holes for fuel injection 78 are formed in the inner tube 26 at a point near the inlet end 74 of the high speed passageway 73 in the mixing / firing section 46 in the embodiment of Figures 1-5 to communicate with the passageway for conducting the fluid 77 formed in the inner tube 26 so that the fuel 33 discharged from the passageway 77 in the inner tube 26 is injected perpendicularly into the swirling air at high speed 20, and discharged from the nozzle-shaped passageway 65 in the air acceleration section 44 of the burner 10. The distance 80 from the injection ports of the fuel 78 to the flame retainer 32 is called the "mixing length" and it is preferably twice the hydraulic diameter, wherein the hydraulic diameter is equal to the internal diameter 70 of the high-speed passageway 73 minus the external diameter 71 of the inner tube 26. The injection of the perpendicular fuel into a stream of air stirred in the form of The swirl causes the fuel 33 to mix with the air 20 in a "complete" manner. By locating the holes for fuel injection 78 near the inlet end 74 of the high-speed passageway 73 after the air 20 has been accelerated to its maximum speed in the burner 10, the probability of having the fuel 33 flowing upstream in the direction 45 again towards the air acceleration section 44, is minimized. Also, by injecting the fuel 33 into the accelerated air, the probability of burning within the burner 10 is minimized.

The holes for fuel injection 78 are positioned to lie in a spaced apart circumferentially relation to each other around the cylindrical outer surface 39 of the inner tube 26 so that the holes for fuel injection 78 are aligned to lie along the a plane 47 that is divided particularly through the inner tube 26, as shown in Figure 1. Preferably, the fuel is injected at a pressure of four times the air pressure and the orifices for the fuel injection 78 are spaced apart from each other. about 45 ° so that the proper amount of the fuel 33 can be injected into the high velocity vortex air 20 at the appropriate stoichiometric ratio. The combination of the mixing length 80, the annular gap 72, and the diameter and spacing of the holes for fuel injection 78 allows the burner 10 to achieve low N0X emissions, given the appropriate air / fuel ratio. The air-fuel mixture travels to the outlet end 76 of the ignition / mixing section 46. The igniter 30 burns the mixture 35 so that the mixture 35 temporarily burns within the high-speed passageway 73 in the exhaust air section. blended / ignited 46 of the burner 10. However, the lighter 30 remains on fire for less than 4 seconds so that the air-fuel mixture will not continue to burn within the high-speed passageway 73 of the ignition / mixing section. Instead of this, because of the acceleration of the flow rate of the vortex air 20 in the nozzle-shaped passageway 65 of the air acceleration section 44, the flow velocity of the air-fuel mixture 35 is high enough (that is, greater than 6.35 kg / square meter (0.25 inches) of water (column) so that the mixture of air and fuel 35 is "pushed" downstream in the direction 43 of the mixing / firing section 46 of the burner 10 by the unburned mixture once the lighter 30 is turned off. After the ignited fuel-air mixture passes through the outlet end 76 of the mixing / ignition section 46, the ignited mixture must pass around the crushed-wide-spanned body flare retainer 32 mounted on the running end. down 29 of the inner tube 26. Preferably, the crushed wide front body flare retainer 32 is offset slightly off the offset distance 49 (i.e., a shorter distance than the inner tube 26) from the outlet end 76 of the mixing / firing section 46 so that the crushed broad-faced body flame retainer 32 lies within the flame chamber 19 formed in the refractory block 16, as shown in Figure 1. This not only improves the mixing allowing more air and fuel to flow out of the outlet end 76, but also allows the flattened wide front body flare retainer 32 to be provided with servi It is easy because a wrench can be applied to a portion of the inner tube 26 so that it extends in the direction 43 past the downstream end 31 of the outer tube 24 without interference from the outer tube 24. Placing the flame retainer of flattened wide front body 32 remote from the air and fuel mixing chamber in the high speed passageway 73, a wider recirculation path can be achieved without having to introduce the fuel 33 out of the flame retainer 32 to stabilize flame 18 without a penalty of N0X. Once the mixture of air and fuel 35 passes through the outlet end 76, the flame 18 is attached to the flattened wide front body flame retainer 32 within the flame chamber 19 in the refractory block 16 in where it continues to burn. Preferably, the refractory block 16 is made of alumina / silica, although other refractory block materials could also be used. In addition, the burner 10 is capable of being operated without using a refractory block 16 and still achieves low NOx emissions with low levels of excess air reaching through the burner. As shown in Figures 1-5, the burner 10 is connected to the refractory block 16 by the front plate 90 and the nuts and bolts 92, 94. Preferably, an observation glass 96 can also be used to ensure that an appropriate flame 18 is burning inside the refractory block 16. Preferably, the front plate 90 is continuously welded to the outer tube 24 to ensure no leakage occurs between the front plate 90 and the outer tube 24. As shown in Figure 3, the burner 10 and the refractory block 16 are generally cylindrical in shape and are connected by the generally circular front plate 90. However, as shown in Figure 5, the burner 10 is also slightly tunnel shaped due to the nozzle-shaped configuration of the air acceleration section 44 located between the upstream air intake section 42 and the mixing / turning section 46 downstream. The air inlet end 36 of the burner 10 is also best shown in Figure 5. As shown in Figure 5, the cyclonizer 28 includes the fins 112 and a portion 114 of the body coupled to the fins 112. The fins 112 radially outwardly from the body portion 114 and are twisted in a fan-like manner so that the air 20 from the air supply 12 is introduced to the air intake section 42 in a vortex manner as shown in FIG. Figure 1. As mentioned above, by locating the cyclonizer 28 in a low velocity environment away from the lighter 30 and the refractory block 16, the cyclonizer 28 is less likely to be damaged by heat or high pressures and therefore It is likely to last longer. The internal fuel tube 26 and the crushed wide front body flare retainer 32 are shown in greater detail in Figure 4. The inner tube 26 is formed to include the holes for fuel injection 78 that are equally spaced around of the circumference of the inner tube 26. Downstream of the holes for fuel injection 78, the flared wide front body flare retainer 32 is fixed to the inner tube 26. The flared wide front body flare retainer 32 not only helps with the mixing of air 20 and fuel (not shown), but the crushed wide-front body flare retainer 32 also closes the downstream end 29 of inner tube 26 so that the fuel 33 discharged towards the upstream end 25 of the inner tube 26 from the fuel supply line 27 is forced to flow out of the holes for the injection of The fuel 78 for mixing with the high-velocity vortex air 20 passing through the annular high-speed passageway 73 surrounding the inner tube 26 and communicating with the fuel injection ports 78. The burner 10 swirls in a swirl the air 20 in a passageway 54 of relatively low velocity (large internal diameter) downstream of the cyclonizer 28 to minimize the pressure drop through the cyclonizer 28. The burner 10 accelerates the air 20 through the nozzle-shaped passageway 65 from the low speed passageway 54 to a fuel injection point (for example 78) to minimize the likelihood that the fuel 33 will flow in the upstream direction 45 after it mixes with the air 20 in the high passages. speed 73. The fuel 33 is injected into the air 20 which moves through the passageway 73 in the burner 10 to avoid the need to create an air premix. and fuel outside the burner 10. The fuel 33 is injected into the rapidly moving air 20 that has been accelerated in the nozzle-shaped passageway 65 to minimize the likelihood of burning occurring within the burner 10. Fuel 33 is injected perpendicular to the air stream 20 in a manner that provides sufficient mixing to achieve low N0X emissions, giving the appropriate proportion and ratio of air and fuel. The burner 10 stabilizes the flame 18 (that is, prevents the flame 18 from being blown away) in the vortex wake of the flared wide front body flame retainer 32, which is positioned to radiate at a short distance 49 ( preferably smaller than a diameter of the throat-pipe, ie, the radial void 72) within the flame chamber 19 formed in the refractory block 16. The burner 10 is used, for example, in the field of the incineration of fumes For example, when carts or trailers are processed through paint systems during the manufacturing process, the burner 10 can be used to burn off the fumes from the paint instead of emitting the fumes into the atmosphere. Similarly, the burner 10 can be used to burn the petroleum fuel vapors that are created when the petroleum fuel is transferred from one process to another. Additionally, the burner 10 can be used to burn the fumes that are created by semiconductor chip manufacturers during a chip manufacturing process. The burner 10 can also be used for other applications in which a burner is necessary. For example, the burner 10 could be used to incinerate liquid or solid waste products from almost any manufacturing process. In addition, the burner 10 could be used to burn-off the waste products that are created during the manufacturing process of the drywall material during a calcination process. The burner 10 could also be used in the kiln industry or the aggregate dryer industry. The burner 10 of the present invention can be configured to achieve low N0X emissions in environments both high in 02 and low in 02.

As mentioned above, a high environment at 02 is one in which the 02 in the process chamber (or furnace chamber) is greater than 12% (typically 17-19%). In this environment, the burner 10 can only achieve low NOx emissions by operating in the excess air mode. In addition, a cyclonizer is necessary to operate in excess air mode. Accordingly, although the burner 10 can operate with or without a cyclonizer 28, the cyclonizer 28 must be included in the burner 10 to achieve low NOx emissions in the high environment at 02. Although the cyclonizer 28 is not necessary for the burner 10 operates, _ a cyclonizer 28 creates a "slow" area in the middle part of the flame that resembles an "eye of the storm" and this helps to stabilize the flame 18 generated by the burner 10. To achieve low emissions of N0X , in a low environment in 02 (ie, where the 02 in the process chamber is less than or equal to 12% - typically less than 6%), a short refractory block 116 is used in conjunction with the burner 10 to achieve low N0X emissions and a cyclonizer is not necessary. This embodiment is described in more detail below with reference to Figures 14-16. The burner 10 incorporates mixing techniques that provide a desirably short burner length. The gas 33 is injected perpendicularly to the air 20 with a flow of the moment that optimizes the mixing within an annulus 73. Then the gas 33 and the air 20 leave the annulus 73 and pass over the flame retainer 32 prior to burning . Because the flame retainer 32 remains outside annulus 73, gas 33 and air 20 have additional time for mixing after leaving annulus 73. The possalid area is larger than annulus 73, which means that the flow 35 decelerates when it exits. The shearing forces created by this deceleration as well as the changes in velocity directly attributable to the flame retainer 32 by themselves mix the gas 33 and the air 20 prior to combustion. Mixing reduces emissions from the burner 10. Leaving the flame retainer 32 outside the annulus 73 requires careful attention to the speeds to prevent burning under the flame retainer 32 but allows very rapid mixing. The holes for fuel injection 78 can be formed at any point in the inner tube 26 as shown, for example, in the embodiments of Figures 6 and 7, to enable the discharge of the fuel 33 conducted through the passageway. 77 in the inner tube 26 towards the high-speed passageway 73 formed in the mixing / ignition section 46. Although the holes for fuel injection 78 are formed in the inner tube 26 at a point near the entrance end 74 of the passageway high speed 73 in the embodiment of Figure 1, the fuel injection ports 78 are moved in a downstream direction 43 in the embodiment of Figure 6 so that they are formed in the inner tube 26 at a point near the exit end 76 of the high-speed passageway 73. However, in the embodiment of Figure 7, the holes for fuel injection 78 are moved in an upstream direction 45 and s formed in a section of the inner tube 26 positioned to lie in the air intake section 42 (low speed passageway 54) near the cyclonizer 28. The holes for fuel injection 78 could also be formed in a section of a tube internal 26 positioned to lie in the air acceleration section 44 (the nozzle-shaped passageway 65). In the embodiments shown in Figures 1-7, the outer tube 24 of the burner 10 is formed to include a single "axi-symmetric" flow passageway 53 defined by the passages 54, 65, 73 that admit air 20 into a passageway. of large diameter 54 which minimizes the pressure drop through the cyclonizer 28 or other obstructions in this place. Because the outer tube 24 is preferably cylindrical, differences in diameter between the inlet portion 42, the outlet portion 46, and the nozzle portion 44 determine how the air 20 or mixture 35 is accelerated. However, as shown in Figure 11, when the shape of the outer tube 24 is somewhat different from the cylindrical one, the differences in the effective cross-sectional areas of the inlet portion 42, the portion 46 of the outlet 35, and the portion of the nozzle 44 determines the acceleration. Accordingly, differences in the effective cross-sectional area between these portions 42, 44, 46 determine the acceleration of air 20 or mixture 35 for the cylindrical cross sections as well as other cross sections. In the embodiments of Figures 1-6, the air 20 is then accelerated to the lighter 30 through the conical portion 44. This eliminates the likelihood of having an upstream fuel flow and improves the air flow distribution if the Inlet air flow is unbalanced. The fuel 33 is then injected into the air 20 at any point within the high-speed passageway 73 (Figures 1-6), to minimize the potential for unwanted pre-ignition that could result if a premix is created in a pipeline train that leads to the burner. However, when the fuel injection ports 78 are moved in an upstream direction 43 from the position shown in Figures 1-5 to the position shown in Figure 6, the distance of the mixing length (from the holes for injection of the fuel 78 to the flame retainer 32) is reduced from a distance 80 in Figures 1-5 to a distance 180 in Figure 6. Although the shorter distance 180 in Figure 6 minimizes the probability of burning within the burner 10, the largest distance 80 in Figures 1-5 is preferable because more "complete" mixing can be effected. The fuel 33 is injected into the air 20 perpendicularly to cause the fuel 33 to mix with the air 20 in a "complete" manner. Finally, the crushed wide front body flame retainer 32 stabilizes the flame 19 inside the combustion chamber 19. As shown in Figure 7, locating the fuel injection holes 78 immediately downstream of the cyclonizer 28 in the low speed passageway 54 formed in the air intake section 44, the fuel 33 can be injected into a region within the burner 10 which contains a low turbulent, low velocity air flow (when compared to the air flow) in the high speed passageway 73 shown in the embodiments of Figures 1-5 and 6). The longitudinal mixing distance 280 between the holes for fuel injection 78 and the flame retainer 32 in the embodiment of Figure 7 is longer than the longitudinal mixing distance 80, 180 shown in the embodiments of Figures 1- 5, and 6, respectively, to facilitate the mixing of air and fuel in the burner. Although injection of the fuel 33 downstream from the cyclonizer 28 reduces the mixing that could be gained by passing the mixture through the cyclonizer 28, this injection of the fuel downstream into the passageway 73, 54, or 56, ensures that the cyclonizer 28 will not be burned, especially at lower flow rates. In the embodiment of Figure 8, there are no holes for fuel injection 78 formed in the inner tube 26 and there is no fuel supply coupled to the inner tube 26. Instead, the inner tube 26 simply acts as a support for the flame retainer 32. As shown in Figure 8, a mixture of pre-mixed fuel and air 220 is admitted to the inlet end 36 of the burner 10. The air-fuel mixture 220 passes through the cyclonizer 28 when the The same is introduced into the air intake section 42. The air-fuel mixture 220 is then accelerated through the conical portion 44 before it is introduced into the cylindrical portion 46. The air-fuel mixture 220 is then ignited. within the cylindrical portion 46 and is forced in the downstream direction 43 to produce a flame (not shown) that is affixed to the flame retainer 32. In the embodiment of Figure 9, the burner of Figure 8 is modified so that the inner tube 26 is formed to include the injection orifices 78 and is coupled to the fuel supply 14. Although the injection orifices 78 are shown at a location near the retainer of the Flame 32, the position of the holes for fuel injection 78 can be any of the positions shown in Figures 1-7 or the description referring to Figures 1-7. Accordingly, in the embodiment of Figure 9, the air-fuel mixture 220 can be supplemented by injecting the fuel 33 through the holes 78 within the passages 54, 65, or 73. Of course, the ratio or proportion The air-fuel mixture of the air-fuel mixture 220 which arrives via the inlet end 36 is not necessarily the same as that which comes through the holes for the injection of the fuel 78. In the embodiment of Figure 10, a fuel injection manifold 260 is used to inject the fuel 33 from the fuel supply 14 to the burner 10 at the air inlet end 36. As shown in Figure 10A, a manifold 260 includes a ring 262 that defines a passage for air flow 264 and a plurality of lightning-like injection tubes 266 for discharging fuel 33 through openings 265 formed in ring 262 in low speed air 20 which passes through the passageway for air flow 264. The injector tubes 266 may or may not be configured to induce swirling of the air 20 passing from the air supply 12 through the spaces between the injector tubes 266 and outside the ring 262. The fuel injection manifold 260 according to this embodiment is configured to inject the fuel 33 through tubes or other suitable injectors into the burner air inlet, whereby the time of air and fuel mixing inside the burner body. A fuel injection manifold according to this mode is very suitable for use with liquid fuels. Further, although not shown in Figure 10, a secondary fuel supply could be coupled to the inner tube 26 with the inner tube 26 which is formed to include the fuel injection holes 78 as shown in Figures 1-7. In the embodiment of Figure 11, the burner 10 can incorporate any of the fuel injection methods described above for Figures 1-10. However, in the embodiment of Figure 11, the passages 54, 65, 73 are rectilinear instead of axi-symmetric as shown in Figures 1-10. As shown in Figure 11, a supplementary fuel injection tube 226 is preferably used to inject the fuel 33 into the air 20. The supplementary tube 226 is coupled to the fuel supply 14 and arranged to extend perpendicularly through the inner tube. 26 as shown in Figure 11 so that the fuel 33 will be evenly distributed in all the rectilinear sections 42, 44, 46. In this embodiment, the holes for fuel injection 78 are formed on the supplementary tube 226 instead of the inner tube 26. This modality could also be extended to cover a tea, a cross, an H, an I, or another suitable form. The inner tube 26 is also used to support the flame retainer 32. Two or more rectilinear burners can be arranged in line as shown in Figure HA to create an in-line burner assembly 211 supplied with fuel by means of the supplementary tube. 226 coupled to the fuel supply 14. In the embodiment of Figure 12, a pair of concentric tubes 280, 282 are used to discharge the secondary fuel 286 and oxygen 288 in the flame retainer 32. Preferably, oxygen 288 is of a purity of 75% or higher, but oxygen purities of less than 75% can also be used. The secondary fuel 286 and the oxygen 288 travel through the tubes 280 and 282 respectively so that the secondary fuel 286 and the oxygen 288 do not burn on the front of the crushed wide front body flame retainer 32 with or without the fuel support 33 which is admitted through the fuel injection holes 78, which can be located on any of the positions shown in Figures 1-7. A primary fuel supply pipe 126 is configured to discharge fuel 33 from the primary fuel supply 14 at the outlet end of the burner flame. The concentric tubes 280, 282 extend through the inlet end of the burner and a portion of the primary fuel supply tube 126 and terminate in the flame retainer 32. In the embodiment of Figure 13, the gas difficult to burn 92 such as secondary gas or a waste gas, is introduced through a single tube (or lancet) 296. The embodiment of Figure 13 is identical to the embodiment of Figure 12 except that only one tube is used 296 A primary fuel supply pipe 126 is configured to discharge fuel 33 from the primary fuel supply 14 at the outlet end of the burner flame. The waste gas tube 296 extends through the inlet end of the burner and a portion of the primary fuel supply tube 126 and terminates in the flame retainer 32. In the embodiments of Figures 14-16, it is used a short refractory block 116. Any of the burners shown in Figures 1-13 can be combined with the short refractory block 116 shown in Figures 14-16. As shown in Figure 14, the burner 10 can be connected to a furnace chamber 17 using the short refractory block 116. With a short refractory block 116, the premix of the air and fuel 35 is introduced to the furnace chamber 17 immediately. during the exit of the outlet end 76 of the cylindrical portion 46. The premix 35 is then mixed with the gases from the oven 240 when the mixture passes around the flame retainer 32. The gases from the oven 240 are those gases that exist in an oven, or another process chamber, which are the byproducts of fuel combustion - these gases contain nitrogen, water vapor, carbon dioxide and excess oxygen, left from the combustion of the fuel. The timing and viscosity of the premix 35 induces a circulating flow of the furnace gases 240 within the combustion chamber 17. The gases from the furnace 240 are drawn into the premix 35 so that the presence of the gas from the furnace 240 in the premix 35 dilute 02 into premix 35 and add to its thermal capacitance. This reduces the adiabatic flame temperature which ultimately reduces the rate of thermal NOx formation. The furnace gas 240 continues to migrate to the premix 35 through a diffusion barrier 241 between the furnace gas 240 and the premix 35 so that the furnace gas 240 is continuously recirculated to the flame 18. Because the short refractory block 116 allows the furnace gas 240 to be recirculated and burned within the furnace chamber 17, no additional pipe is necessary for the recirculation of the gas from the external furnace. Furthermore, the grading of the fuel with the burner of the present invention is not necessary in ambient environments either low in 02 or high in 02. Also, in the environment low in 02, the anti-flashback mechanisms of the flame are not necessary because the fuel comes to be only in one place in such a way that secondary fuel supplied downstream for low environments in 02 is not necessary. The burner of Figure 14 is shown in greater detail in Figure 15. As shown in Figure 15, the burner can be any of the burners shown in Figures 1-13 with the exception that a short refractory block 116 is used. Similarly, Figure 16 shows that any of the burners of Figures 1-15 can be configured without a cyclonizer. All modes have thus far shown a cyclonizer or some other obstruction in the air intake. Such obstruction improves the stability of the flame when the burner is operated with excess air, however, the cyclonizer or the forms of obstruction are not required, under this scenario, the flame is stable near the proportions of air / fuel. stoichiometric which are more likely to be applicable for the environment under 02. Although the invention has been described in detail with reference to certain preferred embodiments, there are variations and modifications within the scope and spirit of the invention as described and defined in the following claims.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following

Claims (44)

1. A burner, characterized in that it comprises: an outer tube defining a flow passage and including a large diameter inlet portion having a large diameter, a small diameter outlet portion having a small diameter that is smaller than the diameter large diameter of the large diameter inlet portion, and a nozzle portion interconnecting an outlet end of the inlet portion and an inlet end of the outlet portion and converging toward the outlet portion to establish the passageway of the inlet portion. flow, an inlet end of the large diameter inlet portion that is adapted to be coupled to an air supply to drive the flow of air through the flow passage to an outlet end of the outer tube and an inner tube of small diameter that is placed to lie in a flow passage of the outer tube, the inner tube has an inlet end placed to settle in the I adjust flow out of the small diameter outlet portion and adapted to be coupled to the fuel supply, the inner tube has a diameter that is smaller than the small diameter of the outer tube, and the inner tube that is formed to include a end downstream opposite the inlet end and a fuel injection orifice positioned to lie in a spaced relation away from the downstream end to drive the fuel flowing from the inlet end of the inner tube through the inner tube towards the air flowing through the flow passage to establish a combustible mixture of the air and the combustible substance within the flow passage, and a flame retainer coupled to the downstream end of the inner tube and positioned to extend beyond one end outlet of the small diameter outlet portion of the outer tube and which lies outside the flow passage of Finished by the outer tube to complement the mixing of the fuel with the air when the combustible mixture of the air and the combustible substance leaves the flow passage of the outlet end of the outer tube to produce a flame of low emissions fixed to the flame retainer during ignition of a combustible mix of air and combustible substance.

2. The burner according to claim 1, characterized in that the orifice for fuel injection is formed in the inner tube so that the orifice is positioned to reside within the small diameter outlet portion of the outer tube.

3. The burner according to claim 2, characterized in that it also comprises a lighter coupled to the external tube, placed to settle between the hole for fuel injection and the flame retainer, and configured to ignite the combustible mixture of air and the substance. gas.

4. The burner according to claim 2, characterized in that a cyclonizer is coupled to the outer tube within the large diameter inlet portion to swirl the air through the flow passage.

5. The burner according to claim 1, characterized in that the orifice for fuel injection is formed in the inner tube so that the orifice is positioned to reside within the nozzle portion of the outer tube.

6. The burner according to claim 5, characterized in that it also comprises a lighter coupled to the external tube, placed to lie between the hole for fuel injection and the flame retainer, and configured to ignite the combustible mixture of air and the substance. gas.

7. The burner according to claim 5, characterized in that a cyclonizer is coupled to the outer tube within the large diameter inlet portion to swirl the air through the flow passage.

8. The burner according to claim 1, characterized in that the orifice for fuel injection is formed in the inner tube so that the orifice is positioned to settle within the large diameter inlet portion of the outer tube.

9. The burner according to claim 8, characterized in that it further comprises a lighter coupled to the external tube, placed to lie between the hole for fuel injection and the flame retainer, and configured to ignite the combustible mixture of air and the substance. gas.

10. The burner according to claim 8, characterized in that a cyclonizer is coupled to the outer tube within the large diameter inlet portion to swirl the air through the flow passage.

11. The burner according to claim 1, characterized in that the inlet end of the large diameter inlet portion is adapted to be coupled to a fuel supply to conduct a mixture of air and fuel through the flow passage.

12. The burner according to claim 1, characterized in that a manifold for fuel injection is adapted to be coupled to the inlet end of the large diameter inlet portion of the outer tube, the manifold includes a ring defining a passage for the air flow and at least one lightning-like injector tube to discharge the fuel through the openings formed in the ring to the air passing through the passageway for air flow.

13. A burner, characterized in that it comprises: an outer tube defining a flow passage and including an inlet portion of the large diameter having a large diameter, a small diameter outlet portion having a small diameter that is smaller than the diameter large diameter of the large diameter inlet portion, and a nozzle portion interconnecting an outlet end of the inlet portion _ and an inlet end of the outlet portion to establish the flow passage, an inlet end the large diameter inlet portion which is adapted to be coupled to an air supply to drive the flow of air through the flow passage to an outlet end of the outer tube, a cyclonizer is coupled to the outer tube within the inlet of large diameter to swirl the air through the passage of flow, means to discharge the fuel into the air passing through s of the flow passage to form a combustible mixture of the air and the combustible substance therein, to discharge it into a flame chamber at the outlet end of the small diameter outlet portion where the means for discharging the fuel includes an inner tube having a diameter smaller than the diameter of the small diameter outlet portion of the outer tube, and a flame retainer coupled to a downstream end of the inner tube and positioned to settle out of the flow passage of the tube external.

14. The burner according to claim 13, characterized in that the inner tube has a hole for the injection of the fuel formed therein for the discharge of the fuel.

15. The burner according to claim 14, characterized in that the orifice for fuel injection is positioned to reside within the small diameter portion of the outer tube.

16. The burner according to claim 13, characterized in that the means for discharging the fuel discharges the fuel in the small diameter outlet portion of the outer tube.

17. The burner according to claim 16, characterized in that a cyclone is coupled to the outer tube within the large diameter inlet portion to swirl the air through the flow passage.

18. The burner according to claim 13, characterized in that the means for discharging the fuel discharges the fuel in the nozzle portion of the outer tube.

19. The burner according to claim 13, characterized in that a cyclonized is coupled to the outer tube inside the large diameter inlet portion d to swirl the air through the flow passage.

20. The burner according to claim 13, characterized in that the means for discharging the fuel discharges the fuel into the large diameter outlet portion of the outer tube.

21. The burner according to claim 20, characterized in that the cyclization is coupled to the outer tube within the entry portion of the larger diameter to agitate the air through the passageway of the flow.

22. The burner according to claim 13, characterized in that the inlet end of the large diameter inlet portion is adapted to be coupled to a fuel supply to conduct a mixture of air and fuel through the flow passage.

23. The burner according to claim 13, characterized in that a multiple pair fuel injection is adapted to be coupled to the input end of the large diameter inlet portion of the outer tube, the manifold including a ring defining a passage for the air flow at least one injector tube similar to a beam to discharge the fuel through openings formed in the ring, towards the air passing through the passageway for air flow.

24. A burner, characterized in that it comprises: means for moving a flow of air in sequence through a first section at a low speed, a second section at an acceleration speed that is higher than the low speed, and a third section a speed elevated which is higher than the acceleration rate and means for discharging the fuel transported in a tube through an opening formed in a side wall of the tube to the air flow to form a combustible mixture of air and the combustible substance in the same, to discharge it towards a flame chamber at the outlet end of the small diameter outlet portion.

25. The burner according to claim 24, characterized in that the means for discharging the fuel discharges the fuel towards the third section.

26. The burner according to claim 24, characterized in that it further includes a cyclonator coupled to the first section to swirl the air flowing through the first, second, and third sections.

27. The burner according to claim 24, characterized in that the means for discharging the fuel discharges the fuel to the second section.

28. The burner according to claim 27, characterized in that it also includes a cyclonizer coupled to the first section to swirl the air flowing through the first, second, and third sections.

29. The burner according to claim 24, characterized in that the means for discharging the fuel discharges the fuel to the first section.

30. The burner according to claim 29, characterized in that it also includes a cyclonator coupled to the first section to swirl the air flowing through the first, second, and third sections.

31. A burner, characterized in that it comprises: an outer tube defining a flow passage and including an inlet portion having a large diameter, an outlet portion having a small diameter that is smaller than the large diameter of the portion of inlet, and a nozzle portion interconnecting an outlet end of the inlet portion and an inlet end of the outlet portion to establish the flow passageway, an inlet end of the large diameter inlet portion that is adapted to be coupled to the supply of the air and fuel mixture to drive the mixture of air and fuel flowing through the flow passage to an outlet end of the outer tube, and a cyclonizer placed inside the inlet portion of the outer tube .

32. The burner according to claim 31 further characterized in that it comprises an inner tube of small diameter which is positioned to lie in the flow passage of the outer tube and which has a diameter that is smaller than the small diameter of the outer tube and a Flared wide front body flare retainer which is coupled to the inner tube and extending beyond an outlet end of the outlet portion of the outer tube ..

33. The burner according to claim 32, characterized in that it also comprises a cyclonator coupled to the external tube to swirl the air flowing through the flow passage.

34. The burner according to claim 33, characterized in that the cyclonizer is placed inside the inlet portion of the outer tube.

35. The burner according to claim 33, characterized in that the cyclonizer is placed inside the nozzle portion of the outer tube.

The burner according to claim 33, characterized in that the? Acr is placed in the outer portion of the "A: external.

37. The burner according to claim 31, characterized in that it further comprises a cyclonator coupled to the external tube to swirl the air flowing through the flow passage.

38. A burner, characterized in that it comprises: an outer tube defining a flow passage and including an inlet portion having a large diameter, an outlet portion having a diameter smaller than the large diameter of the inlet portion, and a nozzle portion interconnecting an outlet end of the inlet portion and an inlet end of the outlet portion and converging toward the outlet portion to establish the flow passageway, an inlet end of the inlet portion of the inlet portion. large diameter which is adapted to be coupled to a supply of the air and fuel mixture to conduct a mixture of air and fuel flowing through the flow passage to an outlet end of the outer tube, an inner tube of small diameter which is positioned to lie in the flow passage of the outer tube, the inner tube has an inlet end adapted to be coupled to a fuel supply , the inner tube having a diameter that is smaller than the small diameter of the outer tube, and the inner tube which is formed to include a plurality of fuel injection orifices positioned within the outlet portion of the small diameter of the outer tube to drive the fuel flowing through the inner tube to the mixture of air and fuel flowing through the flow passage, and a flame retainer coupled to the flame outlet end of the inner tube, the flame retainer it is positioned adjacent to the outlet end of the outer tube.

39. A burner, characterized in that it comprises: an outer tube defining a flow passage and including a large diameter inlet portion having a large diameter, a small diameter outlet portion having a small diameter that is smaller than the diameter large diameter of the large diameter inlet portion, and a portion of the nozzle interconnecting an outlet end of the inlet portion and an inlet end of the outlet portion to establish the flow passage, an inlet end of the large diameter inlet portion that is adapted to be coupled to a supply of the air and fuel mixture to conduct a mixture of air and fuel flowing through the flow passage to an outlet end of the outer tube, and a manifold for fuel injection coupled to the inlet end of the large diameter inlet portion of the outer tube, the manifold includes a ring defining a passageway for the flow of air and at least one injector tube similar to a beam extending between the ring and the outer tube to discharge the fuel through the openings formed in the ring towards the air passing through the passageway for the flow of air.

40. A burner, characterized in that it comprises: an outer shell defining a rectilinear flow passage and including an inlet portion having a large volume, an outlet portion having a volume smaller than the large volume of the inlet portion, and a nozzle portion interconnecting an outlet end of the inlet portion and an inlet end of the outlet portion to establish the rectilinear flow passageway, an inlet end of the large volume inlet portion that is adapted to being coupled to a supply of air to drive the air flowing through the flow passage to an outlet end of the outer shell, and a supplementary tube which is positioned to extend perpendicularly through the flow passage of the outer shell, the supplementary tube has a first end adapted to be coupled to a fuel supply and the supplementary tube is formed to include r a hole for fuel injection to drive the fuel flowing through the supplementary pipe to the air flowing through the rectilinear flow passage.

41. A burner, characterized in that it comprises: a first tube defining a first flow passage and including an inlet portion having a large diameter, an outlet portion having a diameter smaller than the large diameter inlet portion, and a nozzle portion interconnecting the inlet portion and the outlet portion to establish the first flow passage, an inlet end of the large diameter inlet portion that is coupled to an air supply to drive air through the first passage of fluid towards an outlet end of the first tube, a second tube defining a second passage of flow and which is positioned to lie in the first flow passage, the second tube having an inlet end adapted to be coupled to a fuel supply and which is formed to include at least one hole for fuel injection to drive the fuel flowing through the fuel. second flow passage to the air flowing through the first flow passage, the second tube also has an outlet end adapted to be coupled to a flame retainer to prevent fuel from leaving the outlet end of the second tube, the flame retainer is positioned adjacent the outlet end of the outer tube, a third tube defining a third flow passage and which is positioned to lie in the second flow passage, an inlet end of the first tube which is adapted to be coupled to an oxygen supply to conduct the oxygen through the third flow passage to the outlet end of the second tube, the third tube extends through the flame retainer to conduct the oxygen out of the outlet end of the second. tube, and a fourth tube that defines a fourth flow passage and that is positioned to lie in the third flow passage, an inlet end of the first tube that is is adapted to be coupled to a secondary fuel supply to drive the secondary fuel through the fourth passage to the outlet end of the second pipe, the fourth pipe extends through the flame retainer to drive the secondary fuel off the end of exit of the second tube.

42. A burner, characterized in that it comprises: a first tube defining a first flow passage and including an inlet portion having a large diameter, an outlet portion having a diameter smaller than the large diameter inlet portion, and a nozzle portion interconnecting the inlet portion and the outlet portion to establish the first flow passageway, an inlet end of the large diameter inlet portion that is adapted to be coupled to an air supply to drive the air through the first flow passage to an outlet end of the first tube, a second tube defining a second flow passage and which is positioned to reside in the first flow passage, the second tube has an inlet end adapted to be coupled to a fuel supply and which is formed to include at least one orifice for fuel injection to drive the fuel flowing through the second flow passage to the air flowing through the first flow passage, the second tube also has an outlet end adapted to be coupled to a flow retainer. flare to prevent fuel from leaving the outlet end of the second tube, the flame retainer is positioned adjacent the outlet end of the outer tube, and a third tube defining a third flow passage and which is positioned to settle in the second flow passage, an inlet end of the first tube which is adapted to be coupled to a supply of the waste gas to drive the waste gas through the third flow passage to the outlet end of the second tube, the third tube extends through the flame retainer to drive the waste gas out of the outlet end of the second tube.

43. A burner assembly, characterized in that it comprises: a burner having an outer tube that includes an inlet portion and an opposite outlet portion, the outer tube is adapted to be coupled to a furnace chamber such that the inlet portion of the outer tube is positioned to reside outside the furnace chamber and the outlet portion is positioned to reside within the furnace chamber and a short refractory block that is coupled to the outlet portion of the outer tube inside the furnace chamber and which is shorter than the outlet portion such that the outlet portion extends beyond the refractory block further into the furnace chamber.

44. A burner, characterized in that it comprises: an outer tube defining a flow passage and including an inlet portion having a large effective cross-sectional area, an outlet portion having a small effective cross-sectional area, which is more smaller than the effective cross-sectional area of the inlet portion, and a nozzle portion interconnecting an outlet end of the inlet portion and an inlet end of the outlet portion to establish the flow passage, an end of entrance of the inlet portion that is adapted to be coupled to an air supply to drive the air flowing through the flow passage to an outlet end of the outer tube, an inner tube that is positioned to settle into the passage of external tube flow, the inner tube has an inlet end adapted to be coupled to a fuel supply and an opposite downstream end, and The inner tube has an effective cross-sectional area which is smaller than the effective cross-sectional area of the outer tube, and the inner tube which is formed to include a fuel injection orifice placed to lie in a spaced apart relationship with respect to at the downstream end to drive the fuel flowing through the inner tube to the air flowing through the flow passageway to establish a combustible mixture of the air and the combustible substance within the passage, and a flame retainer coupled to the At the downstream end of the inner tube, the flame retainer is positioned to settle out of the flow passage defined by the outer tube to supplement the mixing of the fuel with air as the combustible mixture of the air and the combustible substance leaving the end of the tube. output of the outer tube to produce a flame of low emissions fixed to the flame retainer during the ignition of the combustible mixture of the air and the combustible substance.