US2514768A - Burner, including air feed means - Google Patents

Description

July 11, 1950 J. E. KENNEDY BURNER INCLUDING AIR FEED MEANS Filed March 27, 1946 2 Sheets-Sheet 1 y A 1 W W w J ATTORNEY5 July 11, 1950 J. E. KENNEDY 2,514,763

BURNER INCLUDING AIR FEED MEANS Filed March 27, 1 46 2 Sheets-Sheet z 3 r 1 I3 l4- INVENTOR [ATTORNEYS Patented July 11 -1 U I D is TATES PATENT OFFICE BURNER, CIJUDING AIR FEED Joseph E. Kennedy, New York, N JY.

' Applic'ation'JMarch ZV, 1946, Serial No. 657g4-9fl =7 Claims.

My:inventionrelatesitosimprorementszin steam generator rbumer constructions :adapted for :the effective combustion :of pulverizedmoal and :more particularly :for the :flourning wof v pulverized lanthraciteacoa'l.

- -'ZIhe problem or burning pulverized anthracite coal in steam generators has created considerable difficulties .because of attempts to adapt present generator :constructions .lfOI the use 20f pulverized anthracite coal. Furthermore, anthracite coal varies considerably .in moisture content as well as in rash and other constituents. rIt iis "therefore idi'fiicult to )PYOVidG a furnace burner iconstruction which v isu eadily adjustable iorzhandlin 002115 of warTious :composition and moisture :content. I

iFhepri-mary objectaof :my finrention to ,provide :improved burners .for the efiective handling of pulverized duels.

*Another obj cot-of myzinvention .is :to provide an improved iburner construction which-will :provide for efiec'tive mixing ofrairaand pulverized coal and which :is readily adjustable for variations :in the temperatureioftheipreheatedrairandwthe-composition and fineness of the pulverized =c1oal. l n durther lobiectiofrmy invention is to provide an improved method of 1min; steam generators with pulveriaedriuels. rnccordins to :myinv nt n the improvedburner structure includes :an .air supply :bnxhaving one side openinsintoa combustionchamber, a burner tube having :a ro sesection which is long and narrow for delivering a stream of burning :fuel, the burner tube extending through lt'he air box and opening atsaid:QPfinside-into thecombustion chamber, at: defiector means associated :with the side of the air ibox :opening into the acombustion chamber and with the outlet end :of :the iburner tube for directing air tfrom'the hoxlinto and'toward' the'stream of burning zfuel rdischargedifrom the=burneritube, means ior adjustingrthe deflector means with respect to the sides :of :"the burner tube :out1et,1'a:fuel deflector at "Iea'stas long as the burner tube *outlet ropeningrand :mounted opposite the outlet end of ;the burner tube in the path :of the fuel :issuing therefrom, "and means for ;"supplying air to and through said :fuel ideflec'tor :for use in :burning :fuel r-from the burner tube, the fuel deflector "being constructed and arranged for distributing :airiinto lthe combustion produc'ts-from the burner :tube.

(In the preferred-:nrethod 20f my invention ithe pulverized. coal is produced .by-a tube mill and delivered to :the burners at theatop of :the combustion ;chamber of the generator. :inea stream of preheated air which is preferably produced by the generator. This mixture including primary air, is delivered through the burner-orifices which are preferably flat or elongated and then passed over :a V-shaped -.defiector :so as to substantianydivide-thestreamof fuel of each burner.- In :a preferred construction and method :of opera-v tion ihighly preheated air, which may be called secondaryair, is introduced at a deflected :angle into'the fuel mixture.

In some attempts to burn pulverized anthracite coal considerable losses have been encountered because of the incomplete burning of carbon particles ,.-.a large proportion of which .is carried out with the ash while other quantities are discharged tirom the furnace with the-smoke.

The rieatures 0f construction and :operation 101E my improved burner are illustrated hereinafter in connection with'la steam generator unit.

improved invention .includes :other features and euivantages :which will :be :apparent to ithose skilled in the art :from sthe [fol-lowing rmore detailed description thereof gtaken in connection with. the (accompanying drawings which .:form a part ,of this application,

Imthe-drawings:

.-Fig. .1 is a broken rertical sectional view of -a steam generator unit, the mew-showin particularlythe-construction andarrangement of a portionoithecombustion chamber. v

Eig. v2 is abroken sectional vview taken 313311 the line 22 of Fig. 1, showing theearrangement of the =tube wa11=ofthe=combustionchamber.

.Eig. -3 .-is a vertical sectional view of the .;im proved burner construction of the present :invention, the view being :a broken view taken :on the line-3-3':o fl 3 ig. 6. 3v

Fi 4 tie -.a Al-1 W showing (the bottomrof %the :deflectorlshown in FigSNBand-G.

.PFigU- 5iiS1E broken :top viewpa-rtly inhorizontal section of ithefburnerrconstructiomshownain Fig.

Fig. 6. 1 a broken viewrof the burner construetion shown in :Figs, s3 4 and i5 ataken 1011 :the :ir' rrzgularlined-dofxEigefi.

The steam generator of my invention :is i-illustrated in rconnection with zrelatively ,llarge :units of the t pe used in mower plants in which large quantitiesrof steam'iare@producedias well'asisuper-r heated rsteam. Referring to .Eig. .11 of rt'he :drawings which show such sa plant with parts :largly broken away the installation comprises :a .steam andv water drum to mounted :in the iupper apart of the settin nd iirom which :a sloping roof 12 extends (1OWI1*l7O'1a- Sid8 =Wa1l EH1. .The :ronf :12

and wall i124 are :insulatedand comprise 'zparts fif a combustion chamber it provided with down draft combustion from burners l8 which are supplied with a mixture of preheated air and pulverized coal in the usual manner.

The combustion chamber structure includes an upper header 2!! for the wall 14, an intermediate header 22 spaced substantially directly below the header 20 and a bottom header 24. The wall I4 in addition to including the outer insulated part includes a tube wall comprising closely mounted tubes 26 between the headers 22 and 24, as well as a shadow wall comprising tubes 28 spaced from the tubes 26 and also spaced from each other as shown in the detailed view'of Fig. 2. The upper headers 20 and 22 are connected by relatively short steam generating tubes 38, alternate ones of which are bent out of line so as to provide spaces therebetween. The header 2B is connected with the steam and water drum ID by means of roof tubes 32 which carry the steam and water from the tubes of the wall [4 into the steam and water drum. Water is supplied to the header 24 in the usual manner by a down-comer or supply line not shown.

The combustion gases generated in the upper part of the combustion chamber [6 pass downwardly substantially to the bottom of the chamber and are then directed to the right through suitable passages where the gases are utilized for superheating of steam and othe purposes which are not illustrated and which form no part of the present invention. The ashes produced in the combustion chamber for the most part settle to the bottom and are withdrawn through an ash door 34.

Preheated air is provided for the upper part of the combustion chamber l6 through a duct 36 which for purposes of illustration is mounted opposite the tubes 38 for the convenience of supplying air to the upper part of the combustion chamber around these tubes. For this purpose the side of the air duct 36 is provided with a plurality of dampers 38 for the control of air introduced around the tubes 30. Other preheated air is connected through a duct 40 including branches 42 to the burners 18 mounted in the roof or the combustion chamber. This air first passes into an outer surrounding air supply chamber 44 then into. an air box 46 which immediately surrounds the orifice tube of the burner. The mixture of pulverized coal and primary air for the burner I8 is supplied through ducts 48.

The burners shown more or less diagrammatically in Fig. 1 of the drawings are illustrated in substantial detail in Figs. 3 to 6 inclusive in which it will be noted that the ducts 48 connect directly with flat burner orifice tubes 50 which are shown in cross section. These orifice tubes 50 are mounted in a burner setting or frame work 52 by means of rounded upper side portions 54, which permit the angular adjustment of the oriflce tube, the tube being bolted to the mounting by means of bolts 56 which may be utilized in a well known manner for adjusting the side angle of the orifice tube 50.

The orifice tube 50 in each burner extends through the surrounding air box 46 which is supplied with air from the outer air compartment 44 through a grating 58 on each side of the air box, each grating including a movable slotted slide 60 for controlling the air flow into the box 46. This slide on each side of the burner properly serves as a damper, and it will be noted that as shown in Fig. 5, each is provided with a stop 62.

The slides are operated from the top of the burner mounting by handles 64 mounted on shafts 66 which extend along outside of the gratings and which carry a pinion 68 operating in a rack on the slide as shown in Fig. 6.

The burner construction includes a deflector 10 mounted directly below the burner orifice which comprises a hollow member of triangular cross section with a plurality of holes drilled in the side opposite the end of the burner orifice tube 50. This bottom side is shown in Fig. 4 of the drawings. Preheated air is supplied to the deflector through a pair of end pipes 12, which are preferably connected to a blower not shown so that the air will be supplied at relatively higher pressure than that in the ducts 35 and 40. However, if desired, the supply pipes 12 may be connected into the supply ducts 48 or 42. The supply pipes 12 serve to mount and position the deflector 10 with respect to the mouth of the tube 50, the pipes passing between positioning studs 14 as shown in Figs. 5 and 6, and being held in place by means of adjustable retaining brackets 16 bolted to the top of the mounting 52. The closer the deflector 10 is set to the mouth of the burner tube 50 the greater will be the angle of deflection of the materials discharged from the tube 50.

The air box 46 of each burner has walls which surround and which are spaced substantially from the burner tube 50, these walls opening directly into the combustion chamber Hi. However, each side of the tube 58 is provided with an adjustable louver-like air deflector plate 18 the lower edge of each of which is normally mounted alongside the end of the tube 50. This plate 18 is provided with end lugs as shown in Figs. 5 and 6 which serve as pivot points and which are held to end brackets by means of pivot bolts 82. The end brackets 80 are slotted so that the position of the pivot point of the plates 18 may be adjusted. In the position shown in Fig. 3 the brackets 80 are set so that the plate 18 will be almost as high as possible in the air box 46. This adjustment is correlated with the position of the deflector 10 so that air from the air box 46 is deflected by the plates 18 into the divided streams of fuel-air mixture issuing from the burner tube 50. If the adjustment is such that the deflector I0 is set considerably below the tube 50, the brackets 80 may be lowered so that wider streams of air would be directed into and thoroughly mix with the streams of fuel-air mixture alongside the deflector 10.

Each of the pivoted plates 18 is provided with a lug 84 which in turn is attached to a threaded rod 86 extending through the top of the burner mounting 52. Each rod is threaded to a readily operable nut member 88, the operation of which positions the plates 18. The plates 18 on each side of the burner tube 50 are individually ad- Justed so that the amount of air supplied to each side of the burner 50 may be varied independent- 1y. The flame from the burner therefore may be directed to one side of its normally straight path if desired. These plates 18 are individually adjustable for the further reason that the burner tube 50 may be set at a different angle than that shown in Fig. 3, or some of several burner tubes set at different angles from others.

The combustion chamber shown in Fig. 1 of the drawings will normally be of considerable width so that the roof I 2 will carry a considerable number of the burners l8. In the roof structure the burner mountings terminate in a body of refractory-material andthe burner openings are amended by the motto cs 32 :which are turned out of line at the position act the burners.

In carrying out the operation of the furnace and improyements :in the burning of pulverized anthracite (coal, the coal and primary air mixtune is supplied from the usual type of equipment :to the burnersupply tubes '48 and projected thnough the burner tubes dwagainst the deflectors At rthe same time secondary air is supplied fmmithenair box A-Boyer the plates '18 directly into 'the broad streams .of fuel-air mixture alongside rtheedeflector 7H). 'The 'iniector of the seconda-ry airin this manner creates an intense turbuience iacilita-tes the ignition of all of the meipanticles in the region adjacent to the through, I found that the burning anthracite coal wesgneatly facilitated and "that the operation resulted in a more eiiective operation with considereibly .l'ess carbon in the ash and flue gases. 1 also found that the burning of anthracite coal as well as other coals could be greatly facilitated and improved by means of .a furnace wall construction for introducing tertiary air into the upper part of the combustion chamber. My improved operation therefor'e advantageously includes :the introduction of tertiary air from the duct .35 around the tubes i311 into the burning fiueliin the :upper part :of the combustion chamher; This introduction oflair as well as that from the distributor it adds in maintaining a very high combustion temperature in the upper part ofithetcombustion chamber, thereby keeping the refractory portions of the roof in a very highly heated eo'nditionivhich facilitates the ignition o'f the pulverized fuel. While I have shown the arrangement of the furnace wall for the introduction of tertiary air from the duct 36 only on one side of thechamber I6, it is "to be understood that a similar construction may be provided at the ends of the combustion chamber so that at least a three sides of the chamber include means for introducing tertiaryair at a point or level near but substantially below the burners.

In mounting the burners in the roof [2 they may be ranged in parallel rows or they may be staggered so as to provide a somewhat different distribution across the upper portion of the combustion chamber. Furthermore, sinceeach of the burners are individually adjustable with respect to direction, and with respect to the spacing of the distributor l0 and plates 18, the tubes 50 of some of the burners may be directed at an angle toward a particular side of the furnace in order to increase the temperature at that particular point. Two rows of burners at different elevation are provided as indicated in Fig. 1 of the drawings. The upper row may be operated with the deflectors TB at a lower point than is the case in the lower row of burners so that themain flame or combustion in the upper part of the combustion chamber [6 will be substantiallyat one level. In other words the flames v from the upper burners may be projected farther a 6 into the combustion chamber than from the lower burners. a

. Various other modifications are possible with the particular burner construction used in cooperation with the particular ifurnace wall constructed for the admission of tertiary air. In some cases it may be desirable to have most of the combustion take a lacexat a level above the point of introduction for tertiary air or directly opposite such introduction. These arrangements are possible in view of the flexibility of the particular burner described above. i From the foregoing description it will be ap parent that while the apparatus as described is particularly adapted for the burning of pulverized anthracite and other coals which are difficult to burn, the r-apparatus may be used with considerable advantage in the burning of other fuels which may be gas, liquid .or solid. apparatusmay be modified in some respects without departing from the scope of the invention and still achieve the important vresults described above. .Suchichanges are contemplatedas coming within the scope of the appended claims.

Whatl claim as new is:

1. A burner for steam generators and the like having a combustion chamber comprising e. burner istructureincluding an :air box having one side opening into the combustion chamber, a burner tube havingopposite flat-sides and a crosssection which is long and narrow, the burner tube the flames extending through the air box andopening at said open side and spaced 'irom the side walls of the box, means for conducting fuel and air to the .burnertube, an air supply chamber substantially surrounding the air box, means including air passageways for admitting air from the supply chamber through the sides of the air box, means for varyingthe area of said passageways, adjustable means operatively associated with the end of the air box projecting into the combustion chamber and with the outlet end of the burner tube, said adjustable means including a louverlike yplate adjacent each flat side and near the outlet end of the burner tube for directing air from the box into the stream of fuel and air discharged from the burner tube, a deflector the length of the burner tube opening and mounted opposite the outlet end of the burner tube, and means for supplying air to and through said de fleotor, the deflector being constructed :and arranged for distributing air into the combustion products resulting from the burning of the fuel discharged from the burner tube.

2. A burner for steam generators and the like having a combustion chamber comprising a burner structure including an air box having one side opening into the combustion chamber, a burner tube having a cross-section which is long and narrow, the burner tube extending through the air box and opening at saidopen side and spaced from the side walls of the box, means for conducting fuel and air to the burner tube, an air supply chamber substantially surrounding the air box, means including air passageways for admitting air from the supply chamber through the sides of the air box, means for varying the area of said passageways, adjustable means operatively associated with the end of the air box projecting into the combustion chamber and with the outlet end of the burner tube for directing air from the box into the stream of fuel and air discharged from the burner tube, a deflector at least as long as the burner tube opening and mounted opposite the outlet end of the burner tube, and.

means for supplying air to and through said deflector, the deflector being constructed andarranged for distributing air into the combustion products resulting from the burning of the fuel discharged from the burner tube.

3. A burner for steam generators and the like having a combustion chamber, comprising a burner structure including an air box having one side opening into the combustion chamber, a burner tube having a cross-section which is long and narrow providing opposite broad sides, the burner tube extending through the air box in spaced relation to the side walls thereof and opening'at the open side of the box into the combustion chamber, means for conducting fuel and air to the burner tube, means including air passageways for admitting air through the sides of the air box opposite the broad sides of the burner tube, means for varying the area of said passageways, adjustable means operatively associated with the end of the air box projecting into the combustion chamber and with the outlet end of the burner tube for directing air from the box into the'stream of fuel and air discharged from the burner tube, a deflector opposite the outlet end of the burner tube and extending lengthwise of the tube opening, and means for supplying air to and through said deflector, the deflector having an edge facing the open end of the burner tube and arranged for distributing air from a side opposite said edge into the combustion prod-,

uctsresulting from the burning of the fuel .discharged from the burner tube.

4. A burner for pulverized fuel comprising a burner tube having an oblong-shaped outlet opening, means for conducting fuel and airto the burner tube, an air supply box around said tube arranged to deliver air at the outlet of the tube, along hollow deflector of triangular crosssection mounted opposite and spaced away from the outlet end of the burner tube with an edge facing toward the tube opening so as to divide the stream of fuel and air discharged therefrom,- the deflector extending the full length of the tube outlet opening, means for supplying air to the deflector, and a multiplicity of passageways in the deflector for distributing the air into the burning products resulting from the combustion ipfbthe fuel and airdischarged from the burner u e. 1 I

5. A burner asdefined by claim 4 in which the deflector includes a substantially flat side oppo- 8 site the edge facing the burner tube outlet operi-: ing, said flat side having said multiplicity of air passageways therein.

6. A burner as defined by claim 4 characterized by including an air deflector plate mounted in the air supply box on each long side of the;

burner tube opening, and means for adjustingthe angle of said plates to direct streams of air. toward the opposite sides of the deflector.-

7. A burner for burning pulverized anthracite coal, comprising a burner tube having an oblongshaped outlet opening and through which a mix-.

ture of pulverized anthracite coal and air is delivered, means for conducting fuel and air to the burner tube, a long hollow deflector mounted opposite and spaced away from the outlet end of the burner tube, said deflector having an edge formed by converging side walls facing toward the tube opening and arranged to divide the stream of products issuing therefrom into two substantially flat streams, said deflector extendingthe length of the tube outlet opening and having a wall opposite said edge, a multiplicity of air distributing passageways through the wall opposite said edge, means for supplying preheated air to said deflector for distribution through said passageways into the burning products resulting from the combustion of the fuel and air discharged from the outlet of the burner tube.

JOSEPH E. KENNEDY.

REFERENCES CITED 1 The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Sept. 25, 1930

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