Patent Publication Number: US-9851099-B2

Title: Flat-flame nozzle for burner

Description:
BACKGROUND 
     The present disclosure relates to burners, and particularly to oxygen-fuel burner assemblies. More particularly, the present disclosure relates to nozzles for producing flat flames in oxygen-fuel burner assemblies. 
     SUMMARY 
     According to the present disclosure, a flat-flame nozzle is provided for producing a flat flame in a flame chamber included in a burner assembly. The flat-flame nozzle is configured to conduct fuel from a fuel supply to an ignition zone in the flame chamber. In some illustrative embodiments, the flat-flame nozzle is also configured to conduct oxygen from an oxygen supply to the ignition zone to produce a combustible oxygen-fuel mixture in the flame chamber. 
     In illustrative embodiments, a removable first plate-separation border frame is positioned to lie between a first lower plate and a companion first upper plate. This border frame is configured to cooperate with those plates to form in the flat-flame nozzle a fuel-discharge outlet and a fuel-transport passageway communicating with the fuel-discharge outlet. Fasteners are provided to releasably retain the removable first plate-separation border frame in a stationary position between the first lower plate and the first upper plate to establish a first flow velocity of fuel flowing through the fuel-transport passageway toward the fuel-discharge outlet. The fasteners can be removed by a technician at an industrial plant to allow for replacement of the removable first plate-separation border frame with a relatively thicker or thinner removable alternate first plate-separation border frame. This modification causes a change in the volume of the fuel-transport passageway and the size of the fuel-discharge outlet formed in the flat-flame nozzle. Using the removable alternate first plate-separation border frame of a different thickness establishes a different second flow velocity of fuel flowing through the fuel-transport passageway to and through the fuel-discharge outlet. 
     In illustrative embodiments, each plate-separation border frame includes a separator strip trapped between top and bottom gaskets. The separator strip is made of stainless steel and each gasket is made of a relatively softer material such as copper. The thickness of the plate-separation border frame can be changed by varying the thickness of the separator strip. 
     A collection of plate-separation border frames of varying thicknesses can be stored at an industrial plant so as to be available to technicians. Then the fired capacity of a burner at the plant can be changed in the field by a technician simply by replacing a first plate-separation border frame with an alternate first separation border frame having a different thickness. 
     In other illustrative embodiments, the flat-flame nozzle is configured to conduct streams of oxygen in addition to streams of fuel. Such an oxygen-fuel flat-flame nozzle is formed to include a lower oxygen-transport passageway terminating at a lower oxygen-discharge outlet located below the fuel-discharge outlet and an upper oxygen-transport passageway terminating at an upper oxygen-discharge outlet located above the fuel-discharge outlet. The oxygen-fuel flat-flame nozzle is formed to locate the fuel-transport passageway between the lower and upper oxygen-transport passageways. 
     In illustrative embodiments, the oxygen-fuel flat-flame nozzle includes a second lower plate arranged to lie below and in spaced-apart relation to the first lower plate to locate the lower oxygen-transport passageway and the lower oxygen-discharge outlet therebetween. A removable second plate-separation border frame is arranged to lie between the first and second lower plates. The oxygen-fuel flat-flame nozzle also includes a second upper plate arranged to lie above and in spaced-apart relation to the first upper plate to locate the upper oxygen-transport passageway and the upper oxygen-discharge outlet therebetween. A removable third plate-separation border frame is arranged to lie between the first and second upper plates. 
     Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a sectional view taken along line  1 - 1  of  FIG. 2  of an oxygen-fuel burner unit showing a first embodiment of a flat-flame nozzle configured to conduct fuel and to provide means for generating a flat flame when fuel conducted by the flat-flame nozzle is exposed to oxygen to produce a combustible oxygen-fuel mixture that is ignited and showing that the flat-flame nozzle is arranged to extend through an oxygen-supply housing so that fuel discharged from the flat-flame nozzle mixes in a flame chamber formed in a burner block with oxygen flowing from the oxygen-supply housing into the flame chamber through an oxygen-flow passageway containing portions of the flat-flame nozzle and showing that a rotatable oxygen-flow control valve is coupled to the underside of the oxygen-supply housing and configured to vary the supply of oxygen provided to mix with fuel discharged from the flat-flame nozzle into the flame chamber; 
         FIG. 2  is a perspective view of the oxygen-fuel burner unit of  FIG. 1  with portions broken away to show the horizontally extending flat-flame nozzle mounted in the oxygen-supply housing and arranged to terminate in the flame chamber formed in the burner block and showing a valve rotator configured to provide means for rotating the oxygen-flow control valve of  FIG. 1  about a horizontal axis of rotation to vary the flow of oxygen discharged from an oxygen-distribution system into the oxygen-supply housing; 
         FIG. 3  is a perspective view of the flat-flame nozzle of  FIGS. 1 and 2 ; 
         FIG. 4  is an exploded perspective assembly view of components that cooperate to form the flat-flame nozzle of  FIG. 3  showing a first lower plate, a top cover including a first upper plate and a fuel-inlet pipe coupled to an upstream end of the first upper plate, an unassembled removable first plate-separation border frame arranged to lie between the first lower plate and the first upper plate and defined by a thin U-shaped top gasket, a relatively thicker U-shaped separator strip, and a thin U-shaped bottom gasket, and fasteners for retaining the plates and border frame in stationary positions relative to one another to form the flat-flame nozzle; 
         FIG. 5  is an enlarged side elevation view of the flat-flame nozzle of  FIGS. 1-3  showing an upstream end on the left and a downstream end on the right; 
         FIG. 6  is an end elevation view of the nozzle of  FIG. 5  showing a rectangle-shaped fuel-discharge outlet formed in the downstream end of the flat-flame nozzle of  FIG. 5 ; 
         FIG. 7  is a bottom view of the flat-flame nozzle of  FIG. 5 ; 
         FIG. 8  is a view of an upstream end of the oxygen-fuel burner unit of  FIGS. 1 and 2 ; 
         FIG. 9  is a top plan view of the oxygen-fuel burner unit of  FIG. 8 ; 
         FIG. 10  is a view of a downstream end of the oxygen-fuel burner unit of  FIG. 8 ; 
         FIG. 11  is an enlarged view taken along line  11 - 11  of  FIG. 1  showing a series of three rectangle-shaped oxygen-admission inlets and eight round oxygen-admission inlets formed in a bottom wall of the oxygen-supply housing through which oxygen passes to enter the oxygen-flow passageway formed in the oxygen-supply housing to surround the flat-flame nozzle; 
         FIGS. 12-16  show a flat-flame nozzle made in accordance with a second embodiment of the present disclosure to conduct fuel and oxygen along separate paths through the oxygen-fuel flat-flame nozzle into a flame chamber; 
         FIG. 12  is a sectional view taken along line  12 - 12  of  FIG. 13  of an oxygen-fuel burner unit showing a second embodiment of a flat-flame nozzle configured to conduct fuel and oxygen along separate flow paths to provide means for generating a flat flame and showing (in an illustrative embodiment) that the oxygen-fuel flat-flame nozzle is arranged to extend through an oxygen-supply housing so that fuel and oxygen discharged from the flat-flame nozzle mixes in a flame chamber formed in a burner block cooperate to provide a combustible mixture in the flame chamber and showing that a rotatable oxygen-flow control valve is coupled to the underside of the oxygen-supply housing and configured to vary the supply of oxygen provided to the flame chamber via a primary oxygen chamber formed in the oxygen-supply housing; 
         FIG. 13  is a perspective view of the oxygen-fuel burner unit of  FIG. 12  with portions broken away to show the horizontally extending oxygen-fuel flat-flame nozzle mounted in the oxygen-supply housing and arranged to terminate in the flame chamber formed in the burner block and showing a valve rotator configured to provide means for rotating the oxygen-flow control valve of  FIG. 12  about a horizontal axis of rotation to vary the flow of oxygen discharged from an oxygen-distribution system into the oxygen-supply housing; 
         FIG. 14  is an enlarged perspective view of the oxygen-fuel flat-flame nozzle of  FIGS. 12 and 13 ; 
         FIG. 14A  is an end elevation view of the downstream end of the oxygen-fuel flat-flame nozzle of  FIG. 14  showing in sequence (bottom to top) a rectangular lower oxygen-discharge outlet, a rectangular fuel-discharge outlet, and a rectangular upper oxygen-discharge outlet; 
         FIG. 15  is an exploded perspective assembly view of components that cooperate to form the oxygen-fuel flat-flame nozzle of  FIG. 14  showing a bottom cover including a second lower plate and an oxygen-inlet pipe coupled to an upstream end of the second lower plate, a top cover including a second upper plate and a fuel-inlet pipe coupled to an upstream end of the second upper plate, a series of plates (two) and U-shaped plate-separation border frames (three) arranged to lie between the second lower plate and the second upper plate, and fasteners for retaining the plates and border frames in stationary positions relative to one another to form the flat-flame nozzle and suggesting that each of the thin U-shaped plate-separation border frames could be replaced by an alternate U-shaped plate-separation border frame to change the velocity of fuel or oxygen flowing through a passageway defined by such plate-separation border frames; 
         FIG. 16  is a side elevation view of the oxygen-fuel flat-flame nozzle of  FIG. 12 ; 
         FIG. 16A  is an enlarged sectional view taken in the circled region shown in  FIG. 16  to show that the oxygen-fuel flat-flame nozzle is formed to include a lower oxygen-transport passageway, a (middle) fuel-transport passageway, and an upper oxygen-transport passageway; 
         FIGS. 17-21  show an oxygen-fuel flat-flame nozzle made in accordance with a third embodiment of the present disclosure to conduct fuel and oxygen along separate paths into a flame chamber; 
         FIG. 17  is a sectional view taken along line  17 - 17  of  FIG. 18  of an oxygen-fuel burner unit showing a third embodiment of a flat-flame nozzle configured to conduct fuel and oxygen along separate flow paths to provide means for generating a flat flame and showing that the oxygen-fuel flat-flame nozzle is arranged to extend through an oxygen-supply housing so that fuel and oxygen discharged from the flat-flame nozzle mixes in a flame chamber formed in a burner block to provide a combustible mixture in the flame chamber; 
         FIG. 18  is a perspective view of the oxygen-fuel burner unit of  FIG. 17  with portions broken away to show the horizontally extending oxygen-fuel flat-flame nozzle mounted in the oxygen-supply housing and arranged to terminate in the flame chamber formed in the burner block; 
         FIG. 19  is an enlarged perspective view of the oxygen-fuel flat-flame nozzle of  FIGS. 17 and 18 ; 
         FIG. 19A  is an end elevation view of the downstream end of the oxygen-fuel flat-flame nozzle of  FIG. 19  shown in sequence (bottom to top) a rectangular lower oxygen-discharge outlet, a rectangular fuel-discharge outlet, and a rectangular upper oxygen-discharge outlet; 
         FIG. 20  is an exploded perspective assembly view of components that cooperate to form the oxygen-fuel flat-flame nozzle of  FIG. 19  showing a bottom cover including a second lower plate and an oxygen-inlet pipe coupled to an upstream end of the second lower plate, a top cover including a second upper plate and a fuel-inlet pipe coupled to an upstream end of the second upper plate, and a series of plates (two) and unassembled U-shaped plate-separation border frames (three) arranged to lie between the second lower plate and the second upper plate and each border frame is defined by a thin U-shaped top gasket, a relatively thicker U-shaped separator strip, and a thin U-shaped bottom gasket, and fasteners for retaining the plates and border frames in stationary positions relative to one another to form the flat-flame nozzle; 
         FIG. 21  is a side elevation view of the oxygen-fuel flat-flame nozzle of  FIG. 17 ; and 
         FIG. 21A  is an enlarged sectional view taken in the circled region shown in  FIG. 21  to show that the oxygen-fuel flat-flame nozzle is formed to include a lower oxygen-transport passageway, a (middle) fuel-transport passageway, and an upper oxygen-transport passageway. 
     
    
    
     DETAILED DESCRIPTION 
     A flat-flame nozzle  10  is included in a burner apparatus  12  of an oxygen-fuel combustion system  14  as suggested in  FIGS. 1 and 2 . Flat-flame nozzle  10  is modular and is formed to include interchangeable components that can be changed by technicians in the field as suggested in  FIG. 4  to vary the flow velocity of fuel  16  flowing through the nozzle  10  to allow the fired capacity to be adjusted in the field after installation of burner assembly  12  at an industrial plant. A flat-flame nozzle  110  configured to conduct oxygen  18  and fuel  16  and to be adjusted in the field to vary flow rates of fuel  16  and of oxygen  18  is shown in  FIGS. 12-16 , while another field-adjustable oxygen-fuel flat-flame nozzle  210  is shown in  FIGS. 17-21 . 
     Burner apparatus  12  includes a nozzle-support fixture  20  coupled to a burner block  22  formed to include a flame chamber  24  as suggested in  FIGS. 1 and 2 . Flat-flame nozzle  10  is mounted on nozzle-support structure  20  as suggested in  FIG. 1  and arranged to extend into flame chamber  24 . 
     In use, fuel  16  from fuel supply  16 S is caused to flow in flat-flame nozzle  10  and exit into flame chamber  24  through a fuel-discharge outlet  34  formed in flat-flame nozzle  10  as suggested in  FIG. 1 . Oxygen  18  from oxygen supply  18 S is discharged into an oxygen-supply housing  26  provided in nozzle-support fixture  20  and caused to move through an oxygen-flow passageway  28  interconnecting an interior region  26 I of oxygen-supply housing  26  and flame chamber  24  and containing a downstream portion of flat-flame nozzle  10  as suggested in  FIG. 1 . Fuel  16  discharged from flat-flame nozzle  10  mixes with oxygen  18  discharged from oxygen-flow passageway  28  to produce a combustible oxygen-fuel mixture  19  which is ignited in flame chamber  24  to produce a flat flame  30  as suggested in  FIGS. 1 and 2 . 
     Flat-flame nozzle  10  includes a fluid conductor  32  configured to conduct fuel  16  therethrough. Fluid conductor  32  is formed to include a downstream fuel-discharge outlet  34  and a fuel-inlet pipe  36  coupled to an upstream portion of fuel conductor  32  as shown, for example, in  FIG. 3 . Fluid conductor  32  is formed to include an upstream fuel-receiving plenum  56  and a downstream fuel-transport passageway  37  interconnecting fuel-receiving plenum  56  and fuel-discharge outlet  34  as suggested in  FIG. 1 . Fuel-inlet pipe  36  is adapted to be coupled to fuel supply  16 S via any suitable supply line  16 L as suggested in  FIGS. 1 and 2  and is configured to discharge fuel  16  into fuel-receiving plenum of fuel conductor  32 . 
     Fluid conductor  32  of flat-flame nozzle  10  includes a first lower plate  41 L, a first upper plate  41 U, and a removable (and thus replaceable) first plate-separation border frame  50  comprising a thin U-shaped top gasket  51 , a relatively thicker U-shaped separator strip  52 , and a thin U-shaped bottom gasket  53  as shown, for example, in  FIG. 4 . Upstanding alignment pins  32 P pass through apertures formed in components  41 L,  41 U and  51 - 53  as suggested in  FIG. 4  to align the components with one another before they are fastened together using fasteners  55 . 
     Fasteners  55  are passed through companion fastener-receiving apertures formed in each of plates  41 L,  41 U and border frame components  51 ,  52 ,  53  as suggested in  FIGS. 3 and 4  to retain removable first plate-separation border frame  50  in a stationary position between first lower plate  41 L and first upper plate  41 U to form fuel-discharge outlet  34  and a fuel-transport passageway  37  communicating with fuel-discharge outlet  34 , and an upstream fuel-receiving plenum  56  communicating with fuel-inlet pipe  36  and downstream fuel-transport passageway  37 . The fasteners  55  can be removed by a technician in the field working on a burner apparatus  12  that has been installed in an industrial plant to replace removable first plate-separation border frame  50  with a relatively thicker or thinner removable alternate first plate-separation border frame  50 ′ as suggested diagrammatically in  FIG. 4 . Such a modification can be made to change the fired capacity of burner assembly  12  in the field after installation at the option of the user. 
     A burner apparatus  12  comprises a flat-flame nozzle  10  configured to conduct fuel  16  and to provide means for generating a flat flame  30  when fuel  16  conducted by the flat-flame nozzle  10  is exposed to oxygen  18  to produce an oxygen-fuel mixture that is ignited as suggested in  FIG. 1 . Flat-flame nozzle  10  is formed to include a fuel-discharge outlet  34  and a fuel-transport passageway  37  communicating with fuel-discharge outlet  34  as shown, for example, in  FIGS. 1 and 5 . Flat-flame nozzle  10  includes a first lower plate  41 L, a first upper plate  41 U, and a removable first plate-separation border frame  50  interposed between first lower plate  41 L and first upper plate  41 U as suggested in  FIGS. 3 and 4 . Removable first plate-separation border frame  50  is configured to cooperate with first lower plate  41 L and first upper plate  41 U to form fuel-discharge outlet  34  and fuel-transport passageway  37  as suggested in  FIG. 4 . 
     Flat-flame nozzle  10  also includes fastener means for releasably retaining the removable first plate-separation border frame  50  in a stationary position between first lower plate  41 L and first upper plate  41 U to establish a first flow velocity of fuel  16  flowing through fuel-transport passageway  37  toward fuel-discharge outlet  34  and for allowing replacement of the removable first plate-separation border frame  50  with a removable alternate first plate-separation border frame  50 ′ of a different thickness to establish a different second flow velocity of fuel  16  flowing through fuel-transport passageway  37  toward fuel-discharge outlet  34  as suggested diagrammatically in  FIG. 4 . A technician can exchange border frames in the field to change the fired capacity of burner apparatus  12  easily after installation. 
     Removable first plate-separation border frame  50  is configured to include a first separator strip  52  having a first thickness, a bottom gasket  53  positioned to lie between first lower plate  41 L and first separator strip  52 , and a top gasket  51  positioned to lie between first upper plate  41 U and first separator strip  52 . First separator strip  52  is made of stainless steel and each of bottom and top gaskets  51 ,  53  is made of copper in an illustrative embodiment. 
     Removable alternate first plate-separation border frame  50 ′ is configured to occupy a space between first lower plate  41 L and first upper plate  41 U vacated by the removable first plate-separation border frame  50  to establish the different second flow velocity of fuel  16  flowing through fuel-transport passageway  37  toward fuel-discharge outlet  34  as suggested diagrammatically in  FIG. 4 . Removable alternate first plate-separation border frame  50 ′ is configured to include a second separator strip  52 ′ having a different second thickness, a bottom gasket  53 ′ positioned to lie between first lower plate  41 L and second separator strip  52 ′, and a top gasket  51 ′ positioned to lie between first upper plate  41 U and second separator strip  52 ′ as suggested diagrammatically in  FIG. 4 . 
     The fastener means includes several fasteners  55  and each of the fasteners  55  extends through a companion fastener-receiving aperture formed in each of the first lower plate  41 L, bottom gasket  53 , first separator strip  52 , top gasket  51 , and first upper plate  41 U as suggested in  FIG. 4 . Each of the first lower plate  41 L and the first upper plate  41 U is rectangular and has perimeter portions formed to include the fastener-receiving apertures. Each of first separator strip  52  and bottom and top gaskets  53 ,  51  is U-shaped and arranged to cause an open end thereof to establish a portion of the fuel-discharge outlet  54  as suggested in  FIG. 4 . 
     First upper plate  41 U is formed to include a shallow upper recess  56 U facing toward first lower plate  41 L and arranged to lie in spaced-apart relation to fuel-discharge outlet  34  to locate fuel-transport passageway  37  therebetween as suggested in  FIGS. 1 and 4 . First lower plate  41 L is formed to include a shallow lower recess  56 L facing toward first upper plate  41 U and cooperating with shallow upper recess  56 U and an inner edge  50 E of one of the removable first plate-separation border frame  50  and the removable alternate first plate-separation border frame  50 ′ to form a fuel-receiving plenum  56  as suggested in  FIGS. 1 and 4 . Fuel-receiving plenum  56  is configured to provide fuel distribution means for collecting fuel  16  admitted into the shallow upper recess  56 U and distributing collected fuel  16  into fuel-transport passageway  37  for downstream movement toward fuel-discharge outlet  34  and fuel-transport passageway  37  is arranged to conduct fuel  16  discharged from fuel-receiving plenum  56  to fuel-discharge outlet  34  as suggested in  FIG. 1 . 
     First upper plate  41 U includes an exterior surface facing away from first lower plate  41 L and an interior surface facing toward first lower plate  41 L and defining boundary portions of the shallow upper recess  56 U and fuel-transport passageway  37  as suggested in  FIGS. 1 and 4 . First upper plate  41 U is formed to include a fuel-admission port  57  as shown, for example, in  FIG. 4 . Fuel-admission port  57  has an inlet formed in the exterior surface of first upper plate  41 U and an outlet formed in the interior surface of first upper plate  41 U to open into the shallow upper recess  56 U. Fuel-inlet pipe  36  is coupled to first upper plate  41 U at the fuel-admission port and configured to conduct fuel  16  into the shallow upper recess  56 U for subsequent movement through fuel-transport passageway  37  to and through fuel-discharge outlet  34  as suggested in  FIGS. 1, 3, and 4 . 
     As suggested in  FIG. 4 , each of the first separator strip  52  and the bottom and top gaskets  53 ,  51  includes a first leg L 1 , a second leg L 2  arranged to lie in spaced-apart relation to first leg L 1 , and a bight portion B arranged to interconnect upstream ends of first and second legs L 1 , L 2  and lie in spaced-apart relation to fuel-transport passageway  37 . Shallow lower recess  56 L is located between each of the bight portions B and fuel-transport passageway  37  and between each of the first legs L 1  and each of the second legs L 2 . 
     A flat-flame nozzle  110  in accordance with a second embodiment of the present disclosure is included in a burner apparatus  112  of an oxygen-fuel combustion system  114  as suggested in  FIGS. 12 and 13 . It is within the scope of the present disclosure to use oxygen-fuel flat-flame nozzle  110  by itself apart from the rest of burner apparatus  112  as suggested in  FIG. 14 . 
     A burner apparatus  112  comprises a flat-flame nozzle  110  configured to conduct fuel  16  and oxygen  18  and to provide means for generating a flat flame  130  when fuel and oxygen conducted by flat-flame nozzle  110  is mixed to produce an oxygen-fuel mixture  19  that is ignited. Oxygen-fuel flat-flame nozzle  110  is modular and is formed to include interchangeable components that can be changed by technicians in the field as suggested in  FIG. 15  to vary the flow velocity of fuel  16  and oxygen  18  flowing through the flat-flame nozzle  110  to allow the fired capacity to be adjusted in the field after installation. Flat-flame nozzle  110  is formed to include a fuel-transport passageway  137  conducting fuel  16 , a lower oxygen-transport passageway  138  conducting oxygen  18 , and an upper oxygen-transport passageway  139  conducting oxygen  18  as suggested in  FIGS. 16 and 16A . 
     Burner apparatus  112  includes a nozzle-support fixture  120  coupled to a burner block  122  formed to include a flame chamber  124  as suggested in  FIGS. 12 and 13 . Oxygen-fuel flat-flame nozzle  110  is mounted on nozzle-support fixture  120  as suggested in  FIG. 12  and arranged to extend into flame chamber  124 . 
     In use, fuel  16  from fuel supply  16 S and oxygen  18  from oxygen supply  18 S are caused to flow in oxygen-fuel flat-flame nozzle  110  and exit into flame chamber  124  through separate fuel and oxygen discharge outlets formed in oxygen-fuel flat-flame nozzle  110  as suggested in  FIGS. 12 and 13 . Oxygen-fuel flat-flame nozzle  110  is formed to include lower oxygen-discharge outlet  133 , fuel-discharge outlet  134 , and upper oxygen-discharge outlet  135  as shown, for example, in  FIG. 14A . 
     Oxygen  18  from oxygen supply  18 S is also discharged into an oxygen-supply housing  126  provided in nozzle-support fixture  120  to move through an oxygen-flow passageway  128  interconnecting an interior region  126 I of oxygen-supply housing  126  and flame chamber  124  and containing a downstream portion of oxygen-fuel flat-flame nozzle  110  as suggested in  FIG. 12 . Fuel  16  discharged from flat-flame nozzle  110  mixes with oxygen  18  discharged from lower oxygen-discharge outlet  133  and upper oxygen-discharge outlet  135  and with oxygen  18  discharged from oxygen-flow passageway  128  to produce a combustible oxygen-fuel mixture  19  which is ignited in flame chamber  124  to produce a flat flame  130  as suggested in  FIGS. 12 and 13 . 
     Flat-flame nozzle  110  includes a fluid conductor  132  configured to conduct fuel and oxygen therethrough. Fluid conductor  132  is formed to include a downstream fuel-discharge outlet  134  and a fuel-inlet pipe  136  coupled to an upstream portion of fluid conductor  132  as shown, for example, in  FIG. 14 . Fuel-inlet pipe  136  is adapted to be coupled to fuel supply  16 S via any suitable supply line  16 L as suggested in  FIGS. 12 and 13 . Fluid conductor  132  is also formed to include an oxygen-inlet pipe  131  coupled to an upstream end of fluid conductor  132  as shown in  FIGS. 15 and 16 . 
     Fluid conductor  132  of oxygen-fuel flat-flame nozzle  110  is shown in  FIG. 15  to include (from bottom to top) a second lower plate  142 L, a removable second plate-separation border frame  152 , a first lower plate  141 L, a removable first plate-separation border frame  150 , a first upper plate  141 U, a removable third plate-separation border frame  153 , and a second upper plate  142 U. Fasteners  155  can be used to hold all of these components together to produce fluid conductor  132 . A collection of three alternate border frames  152 ′,  150 ′, and  153 ′ is provided for technicians to use in the field as replacements for border frames  152 ,  150 , and  153  in accordance with the present disclosure to change the firing capacity of burner apparatus  112  as suggested in  FIG. 15 . 
     Each of border frames  152 ,  150 , and  153  (and alternate border frames  152 ′,  150 ′, and  153 ′) comprises a U-shaped separator strip, a U-shaped top gasket, and a U-shaped bottom gasket as disclosed in the embodiment of  FIGS. 1-11 . The thickness of each border frame can be varied by, for example, varying the thickness of the separator strip. 
     Flat-flame nozzle  110  also includes fastener means comprising several fasteners  155  for releasably retaining the removable first plate-separation border frame  150  in a stationary position between first lower plate  141 L and first upper plate  141 U to establish a first flow velocity of fuel  16  flowing through fuel-transport passageway  137  toward fuel-discharge outlet  134  and for allowing replacement of the removable first plate-separation border frame  150  with a removable alternate first plate-separation border frame  150 ′ of a different thickness to establish a different second flow velocity of fuel  16  flowing through fuel-transport passageway  137  toward fuel-discharge outlet  134  as suggested in  FIG. 15 . Removable alternate first plate-separation border frame  150 ′ is configured to occupy a space between first lower plate  141 L and first upper plate  141 U vacated by removable first plate-separation border frame  150  to establish the different second flow velocity of fuel  16  flowing through fuel transport passageway  137  toward fuel-discharge outlet  134  as suggested in  FIG. 15 . A technician can exchange border frames in the field to change the fired capacity of burner apparatus  112  easily after installation. 
     Fasteners  155  are passed through companion fastener-receiving apertures formed in each of plates  142 L,  141 L,  141 U, and  142 U and border frames  151 ,  152 , and  153  as suggested in  FIGS. 14 and 15  to retain the border frames  151 - 153  in fixed positions relative to the plates  142 L,  141 L,  141 U, and  142 U as suggested in  FIG. 15 . Fasteners  155  can be removed by a technician in the field to replace removable first plate-separation border frame  150  with a relatively thicker or thinner removable alternate first plate-separation border frame  150 ′ as suggested diagrammatically in  FIG. 15 . Similarly, border frame  152 ′ can replace border frame  152  and border frame  153 ′ can replace border frame  153 . Such a modification can be made to change the fired capacity of burner  112  to be changed in the field by changing fuel and/or oxygen velocity flow rates in oxygen-fuel flat-flame nozzle  110  after installation at the option of the user. 
     Oxygen-fuel flat-flame nozzle  110  is also formed to include a lower oxygen-discharge outlet  133  and a lower oxygen-transport passageway  138  communicating with lower oxygen-discharge outlet  133  as suggested in  FIGS. 14A, 15 , and  16 . Flat-flame nozzle  110  also includes a second lower plate  142 L and a removable second plate-separation border frame  152  interposed between the first and second lower plates  141 L,  142 L and configured to cooperate therewith to form lower oxygen-discharge outlet  133  and lower oxygen-transport passageway  138 . The fastener means is configured to provide means for releasably retaining the removable second plate-separation border frame  152  in a stationary position between first and second lower plates  141 L,  142 L to establish a first flow velocity of oxygen  18  flowing through lower oxygen-transport passageway  138  toward lower oxygen-discharge outlet  133  and for allowing replacement of the removable second plate-separation border frame  152  with a removable alternate second plate-separation border frame  152 ′ of a different thickness to establish a different second flow velocity of oxygen  18  flowing through lower oxygen-transport passageway  138  toward lower oxygen-discharge outlet  133 . Removable alternate second plate-separation border frame  152 ′ is configured to occupy a space between first and second lower plates  141 L,  142 L vacated by removable second plate-separation border frame  152  to establish the different second flow velocity of oxygen  18  flowing through lower oxygen-transport passageway  138  toward lower oxygen-discharge outlet  133 . 
     Oxygen-fuel flat-flame nozzle  110  is also formed to include an upper oxygen-discharge outlet  135  and an upper oxygen transport passageway  139  communicating with upper oxygen-discharge outlet  135  as suggested in  FIGS. 14A, 15 , and  16 . Flat-flame nozzle  110  also includes a second upper plate  142 U and a removable third plate-separation border frame  153  interposed between first and second upper plates  141 U,  142 U and configured to cooperate therewith to form upper oxygen-discharge outlet  135  and upper oxygen-transport passageway  139 . The fastener means is configured to provide means for releasably retaining the removable third plate-separation border frame  153  in a stationary position between first and second upper plates  141 U,  142 U to establish a first flow velocity of oxygen  18  flowing through upper oxygen-transport passageway  139  toward upper oxygen-discharge outlet  135  and for allowing replacement of the removable third plate-separation border frame  153  with a removable alternate third plate-separation border frame  153 ′ of a different thickness to establish a different second flow velocity of oxygen  18  flowing through upper oxygen-transport passageway  139  toward upper oxygen-discharge outlet  135 . Removable alternate third plate-separation border frame  153 ′ is configured to occupy a space between first and second upper plates  141 U,  142 U vacated by removable third plate-separation border frame  153  to establish the different second flow velocity oxygen  18  flowing through upper oxygen-transport passageway  139  toward upper oxygen-discharge outlet  135 . 
     Second upper plate  142 U is formed to include an exterior fuel-admission port  100 E communicating with fuel-inlet pipe  136  as shown in  FIG. 15 . Each of the second upper plate  142 U, removable third plate-separation border frame  153 , and first upper plate  141 U is formed to include an interior fuel-admission port  100 I. Fuel-admission ports  100 I are aligned with one another and cooperate to provide fuel conductor means  100  for conducting fuel  16  discharged into the exterior fuel-admission port  100 E formed in second upper plate  142 U along a path  100 P into fuel-transport passageway  137  for subsequent movement through fuel-transport passageway  137  to and through fuel-discharge outlet  134  as suggested in  FIG. 15 . Second upper plate  142 U is also formed to include a shallow upper recess  156 U facing toward first upper plate  141 U to cooperate with first upper plate  141 U to form an oxygen-receiving plenum therebetween communicating with an upstream end of upper oxygen-transport passageway  135  as suggested in  FIG. 15 . 
     Second lower plate  142 L is formed to include an exterior oxygen-admission port  101 E communicating with oxygen-inlet pipe  131  and with the lower oxygen-transport passageway  138  as suggested in  FIG. 15 . Each of the first lower plate  141 L, removable first plate-separation border frame  150 , and first upper plate  141 U is formed to include a first interior oxygen-admission port  101 I. First interior oxygen-admission ports  101 I are aligned with one another and cooperate to provide first oxygen conductor means  101  for conducting a first portion of the oxygen  16  discharged into the lower oxygen-transport passageway  138  through the exterior oxygen-admission port  101 E formed in second lower plate  142 L along a first path  101 P into the upper oxygen-transport passageway  139  for subsequent movement through the upper oxygen-transport passageway  139  to and through the upper oxygen-discharge outlet  135  while a second portion of the oxygen  18  discharged into the lower oxygen-transport passageway  138  through the exterior oxygen-admission port  101 E formed in second lower plate  142 L flows through the lower oxygen-transport passageway  138  to and through the lower oxygen-discharge outlet  133  as suggested in  FIG. 15 . Second lower plate  142 L is also formed to include a shallow lower recess  156 L facing toward first lower plate  141 L to cooperate with first lower plate  141 L to form an oxygen-receiving plenum therebetween communicating with an upstream end of lower oxygen-transport passageway  133  as suggested in  FIG. 15 . 
     Each of the first lower plate  141 L, removable first plate-separation border frame  150 , and first upper plate  141 U is formed to include a second interior oxygen-admission port  102 I. Second interior oxygen-admission ports  102 I are aligned with one another and cooperate to provide second oxygen conductor means  102  for conducting a third portion of the oxygen  18  discharged into the lower oxygen-transport passageway  138  through the exterior oxygen-admission port formed in second lower plate  142 L along a separate second path  102 P into the upper oxygen-transport passageway  139  for subsequent movement through the upper oxygen-transport passageway  139  to and through upper oxygen-discharge outlet  135 . In an illustrative embodiment, interior fuel-admission port  100 I is formed in first upper plate  141 U to lie between interior oxygen-admission ports  101 I,  102 I as shown in  FIG. 15 . 
     A flat-flame nozzle  210  in accordance with a third embodiment of the present disclosure is included in a burner apparatus  212  of an oxygen-fuel combustion system  214  as suggested in  FIGS. 17 and 18 . It is within the scope of the present disclosure to use oxygen-fuel flat-flame nozzle  210  by itself apart from the rest of burner apparatus  212  as suggested in  FIG. 19 . 
     A burner apparatus  212  comprises a flat-flame nozzle  210  configured to conduct fuel  16  and oxygen  18  and to provide means for generating a flat flame  230  when fuel and oxygen conducted by flat-flame nozzle  210  is mixed to produce an oxygen-fuel mixture  19  that is ignited as suggested in  FIGS. 17 and 18 . Oxygen-fuel flat-flame nozzle  210  is modular and is formed to include interchangeable components that can be changed by technicians in the field as suggested in  FIG. 20  to vary the flow velocity of fuel  16  and oxygen  18  flowing through the flat-flame nozzle  210  to allow the fired capacity to be adjusted in the field after installation. Flat-flame nozzle  210  is formed to include a fuel-transport passageway  237  conducting fuel  16 , a lower oxygen-transport passageway  238  conducting oxygen  18 , and an upper oxygen-transport passageway  239  conducting oxygen  18  as suggested in  FIGS. 21 and 21A . 
     Burner apparatus  212  includes a nozzle-support fixture  220  coupled to a burner block  222  formed to include a flame chamber  224  as suggested in  FIGS. 17 and 18 . Oxygen-fuel flat-flame nozzle  210  is mounted on nozzle-support fixture  220  as suggested in  FIG. 17  and arranged to extend into flame chamber  224 . 
     In use, fuel  16  from fuel supply  16 S and oxygen  18  from oxygen supply  18 S are caused to flow in oxygen-fuel flat-flame nozzle  210  and exit into flame chamber  224  through separate fuel and oxygen discharge outlets formed in oxygen-fuel flat-flame nozzle  210  as suggested in  FIGS. 17 and 18 . Oxygen-fuel flat-flame nozzle  210  is formed to include lower oxygen-discharge outlet  233 , fuel-discharge outlet  234 , and upper oxygen-discharge outlet  235  as shown, for example, in  FIG. 19A . Fuel  16  discharged from flat-flame nozzle  110  mixes with oxygen  18  discharged from lower oxygen-discharge outlet  233  and upper oxygen-discharge outlet  235  to produce a combustible oxygen-fuel mixture  19  which is ignited in flame chamber  224  to produce a flat flame  230  as suggested in  FIGS. 17 and 18 . 
     Flat-flame nozzle  210  includes a fluid conductor  232  configured to conduct fuel  16  and oxygen  18  therethrough. Fluid conductor  232  is formed to include a downstream fuel-discharge outlet  234  and a fuel-inlet pipe  236  coupled to an upstream portion of fluid conductor  232  as shown, for example, in  FIG. 19 . Fuel-inlet pipe  236  is adapted to be coupled to fuel supply  16 S via any suitable supply line  16 L as suggested in  FIGS. 17 and 18 . Fluid conductor  232  is also formed to include an oxygen-inlet pipe  231  coupled to an upstream end of fluid conductor  232  as shown in  FIGS. 20 and 21 . 
     Fluid conductor  232  of oxygen-fuel flat-flame nozzle  210  is shown in  FIG. 20  to include (from bottom to top) a second lower plate  242 L, a removable second plate-separation border frame  252 , a first lower plate  241 L, a removable first plate-separation border frame  250 , a first upper plate  241 U, a removable third plate-separation border frame  253 , and a second upper plate  242 U. Fasteners  255  can be used to hold all of these components together to produce fluid conductor  232 . A collection of three alternate border frames  252 ′,  250 ′, and  253 ′ is provided for technicians to use in the field as replacements for border frames  252 ,  250 , and  253  in accordance with the present disclosure to change the firing capacity of burner apparatus  212  as suggested in  FIG. 20 . 
     Each of border frames  252 ,  250 , and  253  (and alternate border frames  252 ′,  250 ′, and  253 ′) comprises a U-shaped separator strip, a U-shaped top gasket arranged to lie above the companion separator strip, and a U-shaped bottom gasket arranged to lie below the companion separator strip as shown in  FIG. 20 . The thickness of each border frame can be varied by, for example, varying the thickness of the separator strip. 
     Flat-flame nozzle  210  also includes fastener means comprising several fasteners  255  for releasably retaining the removable first plate-separation border frame  250  in a stationary position between first lower plate  241 L and first upper plate  241 U to establish a first flow velocity of fuel  16  flowing through fuel-transport passageway  237  toward fuel-discharge outlet  234  and for allowing replacement of the removable first plate-separation border frame  250  with a removable alternate first plate-separation border frame  250 ′ of a different thickness to establish a different second flow velocity of fuel  16  flowing through fuel-transport passageway  237  toward fuel-discharge outlet  234  as suggested in  FIG. 20 . Removable alternate first plate-separation border frame  250 ′ is configured to occupy a space between first lower plate  241 L and first upper plate  241 U vacated by removable first plate-separation border frame  250  to establish the different second flow velocity of fuel  16  flowing through fuel transport passageway  237  toward fuel-discharge outlet  234  as suggested in  FIG. 20 . A technician can exchange border frames in the field to change the fired capacity of burner apparatus  212  easily after installation. 
     Fasteners  255  are passed through companion fastener-receiving apertures formed in each of plates  242 L,  241 L,  241 U, and  242 U and border frames  250 ,  252 , and  253  as suggested in  FIGS. 19 and 20  to retain the border frames  250 ,  252 , and  253  in fixed positions relative to the plates  242 L,  241 L,  241 U, and  242 U as suggested in  FIG. 20 . Fasteners  255  can be removed by a technician in the field to replace removable first plate-separation border frame  250  with a relatively thicker or thinner removable alternate first plate-separation border frame  250 ′ as suggested diagrammatically in  FIG. 20 . Similarly, border frame  252 ′ can replace border frame  252  and border frame  253 ′ can replace border frame  253 . Such modifications can be made to change the fired capacity of burner  212  to be changed in the field by changing fuel and/or oxygen velocity flow rates in oxygen-fuel flat-flame nozzle  210  after installation at the option of the user. 
     Oxygen-fuel flat-flame nozzle  210  is also formed to include a lower oxygen-discharge outlet  233  and a lower oxygen-transport passageway  238  communicating with lower oxygen-discharge outlet  233  as suggested in  FIGS. 19A, 20 , and  21 . Flat-flame nozzle  210  also includes a second lower plate  242 L and a removable second plate-separation border frame  252  interposed between the first and second lower plates  241 L,  242 L and configured to cooperate therewith to form lower oxygen-discharge outlet  233  and lower oxygen-transport passageway  238 . The fastener means is configured to provide means for releasably retaining the removable second plate-separation border frame  252  in a stationary position between first and second lower plates  241 L,  242 L to establish a first flow velocity of oxygen  18  flowing through lower oxygen-transport passageway  238  toward lower oxygen-discharge outlet  233  and for allowing replacement of the removable second plate-separation border frame  252  with a removable alternate second plate-separation border frame  252 ′ of a different thickness to establish a different second flow velocity of oxygen  18  flowing through lower oxygen-transport passageway  238  toward lower oxygen-discharge outlet  233 . Removable alternate second plate-separation border frame  252 ′ is configured to occupy a space between first and second lower plates  241 L,  242 L vacated by removable second plate-separation border frame  252  to establish the different second flow velocity of oxygen  18  flowing through lower oxygen-transport passageway  238  toward lower oxygen-discharge outlet  233 . 
     Oxygen-fuel flat-flame nozzle  210  is also formed to include an upper oxygen-discharge outlet  235  and an upper oxygen transport passageway  239  communicating with upper oxygen-discharge outlet  235  as suggested in  FIGS. 19A, 20 , and  21 . Flat-flame nozzle  210  also includes a second upper plate  242 U and a removable third plate-separation border frame  253  interposed between first and second upper plates  241 U,  242 U and configured to cooperate therewith to form upper oxygen-discharge outlet  235  and upper oxygen-transport passageway  239 . The fastener means is configured to provide means for releasably retaining the removable third plate-separation border frame  253  in a stationary position between first and second upper plates  241 U,  242 U to establish a first flow velocity of oxygen  18  flowing through upper oxygen-transport passageway  239  toward upper oxygen-discharge outlet  235  and for allowing replacement of the removable third plate-separation border frame  253  with a removable alternate third plate-separation border frame  253 ′ of a different thickness to establish a different second flow velocity of oxygen  18  flowing through upper oxygen-transport passageway  239  toward upper oxygen-discharge outlet  235 . Removable alternate third plate-separation border frame  253 ′ is configured to occupy a space between first and second upper plates  241 U,  242 U vacated by removable third plate-separation border frame  253  to establish the different second flow velocity oxygen  18  flowing through upper oxygen-transport passageway  239  toward upper oxygen-discharge outlet  235 . 
     Second upper plate  242 U is formed to include an exterior fuel-admission port  200 E communicating with fuel-inlet pipe  236  as shown in  FIG. 20 . Each of the second upper plate  242 U, removable third plate-separation border frame  253 , and first upper plate  241 U is formed to include an interior fuel-admission port  2001 . Fuel-admission ports  2001  are aligned with one another and cooperate to provide fuel conductor means  200  for conducting fuel  16  discharged into the exterior fuel-admission port  200 E formed in second upper plate  242 U along a path  200 P into fuel-transport passageway  237  for subsequent movement through fuel-transport passageway  237  to and through fuel-discharge outlet  234  as suggested in  FIG. 20 . 
     Second lower plate  242 L is formed to include an exterior oxygen-admission port  201 E communicating with oxygen-inlet pipe  231  and with the lower oxygen-transport passageway  238  as suggested in  FIG. 20 . Each of the first lower plate  241 L, removable first plate-separation border frame  250 , and first upper plate  241 U is formed to include a first interior oxygen-admission port  2011 . First interior oxygen-admission ports  2011  are aligned with one another and cooperate to provide first oxygen conductor means  201  for conducting a first portion of the oxygen  16  discharged into the lower oxygen-transport passageway  238  through the exterior oxygen-admission port  201 E formed in second lower plate  242 L along a first path  201 P into the upper oxygen-transport passageway  239  for subsequent movement through the upper oxygen-transport passageway  239  to and through the upper oxygen-discharge outlet  235  while a second portion of the oxygen  18  discharged into the lower oxygen-transport passageway  238  through the exterior oxygen-admission port  201 E formed in second lower plate  242 L flows through the lower oxygen-transport passageway  238  to and through the lower oxygen-discharge outlet  233  as suggested in  FIG. 20 . 
     Each of the first lower plate  241 L, removable first plate-separation border frame  250 , and first upper plate  241 U is formed to include a second interior oxygen-admission port  2021 . Second interior oxygen-admission ports  2021  are aligned with one another and cooperate to provide second oxygen conductor means  202  for conducting a third portion of the oxygen  18  discharged into the lower oxygen-transport passageway  238  through the exterior oxygen-admission port  201 E formed in second lower plate  242 L along a separate second path  202 P into the upper oxygen-transport passageway  239  for subsequent movement through the upper oxygen-transport passageway  239  to and through upper oxygen-discharge outlet  235 . In an illustrative embodiment, interior fuel-admission port  2001  is formed in first upper plate  241 U to lie between interior oxygen-admission ports  2011 ,  2021  as shown in  FIG. 20 . 
     Flat-flame nozzles in accordance with the present disclosure are configured to allow for the design and manufacture of high-aspect ratio (width to height) nozzles that produce flat-flame patterns. These nozzles comprise flat sheets formed to include special-shaped patterns cut using lasers or water jets. The flat sheets are stacked and fastened together to create a fuel path or fuel and oxygen flow paths that give the resulting flame its flat shape. 
     Because the flow paths for oxygen and fuel are shaped from individual sheets and those sheets are held together with removable fasteners, it is simple for technicians working in the field to disassemble flat-flame nozzles in accordance with the present disclosure and substitute a new sheet for either the oxygen or fuel flow passageway. For example, by replacing the fuel gas flow sheet with a thinner or thicker material metal, the effective capacity of the burner can be changed in the field without replacing the burner. Since flame luminosity can be determined in large part by the fuel velocity, in this way, the capacity of a burner in accordance with the present disclosure can be increased or decreased without changing the flame luminosity. 
     Flat-flame nozzles in accordance with the present disclosure use a metal sheet (made, for example, of stainless steel) cut by laser or water jet to create a flat-flame shape. Two matching thin-cut sheets of copper material (or other soft oxygen-compatible metal) are used on both sides of the specially shaped sheet to effect a gas seal to prevent fuel gas leakage from the nozzle. The sheet and the two copper gaskets are sandwiched between a full top and bottom sheet of standard thickness to form the fluid containment walls of the nozzle. The special-cut stainless steel (border frame) sheets can be produced from various thicknesses of material, and in this way, can be used to vary the flow capacity of the fuel gas nozzle. In use, the flat-flame nozzle would install into a burner housing and block in which the oxygen required for combustion would pass over, under, and around the fuel gas nozzle to mix and ignite in a flame zone beyond the end of the fuel gas nozzle. 
     In embodiments suggested, for example, in  FIGS. 12-21 , two additional border frames (each comprising a separator strip sheet and top and bottom gaskets) are provided and constructed to carry oxygen on both sides of fuel conducted through the nozzle. The oxygen is separated from the fuel by a full-size sheet provided between the oxygen cavities and the fuel cavity. Special flow passages cut into the nozzle sheets allow for oxygen to pass through the fuel gas layer without mixing with the fuel. In use, this oxygen-fuel flat-flame nozzle could be inserted through a slot in a wall or block without a housing required. The oxygen and fuel would mix and ignite at some point past the downstream end of the nozzle. 
     In accordance with the present disclosure, flat configuration fuel gas-oxygen nozzles are designed and manufactured with high aspect ratios. Burner nozzles in accordance with the present disclosure have aspect ratios ranging from about 10:1 to about 100:1. 
     Glass melting furnace use mainly radiant heat transfer. A burner nozzle that creates a flat thin flame over the glass surface is provided in accordance with the present disclosure to maximize the flame surface area directly over the surface of the glass. 
     When a glass furnace is designed, a burner firing capacity (measured in BTU&#39;s per hour) is specified by the designer. Replacement of the burner may be needed if the designer overestimates or underestimates the required burner firing capacity. In accordance with the present disclosure, a flat-flame nozzle is provided for a burner that allows the fired capacity to be adjusted simply and easily in the field by a technician. Such a flat-flame nozzle can be modified in the field to allow for fired capacity changes. By varying fuel velocity, a flame can be produced that is luminous and highly radiative as described by glass manufacturers or pale to blue for those end users preferring less transfer of radiation from the flame to the workload. Being able to determine and maintain an optimal fuel velocity in accordance with the present disclosure for maximum flame luminosity would improve glass furnace efficiency and performance.