US2561839A - Boiler - Google Patents

Description

R. K. BEHR July 24, 1951 BOILER 2 Sheets-Sheet 1 Filed June 2, 1945 INVENTOR fizgerzf K 36/72" ATTORNEY July 24, 1951 2,561,839

R. K. BEHR BOILER Fil ed June 2, 1945 2 Sheets-Sheet 2 U U U 0 0 OOOOO 00000 F OUDU f) 025%0000 3) OOOOOOOOOOOOOOO 0 0o 00 oo o 000 00 o iso 2:2 asses P58 88 w;

2?; oo DDOOHOOI'SOOOOOHOQ OOOOOOOOOOUOOOOOOOOOOQOOOOOOOQOOO o 0 88800 8 So 008 0000000 00 0000000 lNVENTOR J ATTORNEY Patented July 24, 1951 rUNITED" STATE J v N 30mm a I 1 Robert K. Behr 'luckahoe, N. Y.; assignor to The Babcock .& Wilcox Company, Rockleigh N l, L

I a corporation ofNew Jersey Application June 2, 1945,Serial-No. 597,201

I The invention herein construction and 'operation of a typemi'water tube boiler having a considerable portion of its heating surface formed of water tubes arranged laterally adjacent an chamber.

My invention relates especially to boilers of the "character described wherein the spacecontaining-boiler' tubes is partitioned fromithe combustion chamber andan entrance for heating gases "is provided at one end adjacent a wall of the setting. Theboiler tubes are suitablyarrangedin "a' bank extending between opposite walls of. the setting and the heating gases which enter from the combustion chamber adjacent one of the wallsareusually directed horizontally in one or more heating gas-passes across the boiler tubes for discharge from the setting adjacent thepoppositewall.

With certain combustion chamber arrangements, "including for example the disposition of 'firing means for the chamber, the heating gases approaching the entrance to the boiler space are caused to flow: through the combustion chamber in 'a' direction generally longitudinally of thepar- "ti'tion wan whereupon, after entering the. space, the gases flowthrough the heating pass or passes in the opposite direction also generally longitudinally of 'the wall. The gases are therefore compelled to make-an abrupt turn of substan 'tially 90 to enter ithe first heating gas pass and thereafter to. completely .reverse their previous direction of flow to continue their passageto the boiler gas outlet. Y In suchconstructions, there uneven distribution of "heating gases .1301 boiler tubes at the: entrance to the first heatinggas pass, both as to gas temperature and gas quantity and, as aresult, certain of theboiler tubes adjacent the entrance are deprived of their proportionate share of the heating effect of such gases whichto some extent impairsthe efficiency oizthe boiler unitf When the fuel is pulverized coal or the like, those: boiler tubes which lie in the. path of concentrated heating gas flow are aptqto become heavi1y-coated with slag which also contributes associated combustion is a tendency for disclosed relates to the 1 cra (01. 1224336) mum transfer of heat to be obtained throughout the superheater without exceeding the maximum safe operating .temperature of the superheater .20 even distribution of heating gases to a heating gas to. decreased operating efficiency of the unit, ha

sidesnecessitating. frequent cleaning of the tubes.

-'Unequal distribution of gas flow intothe first heating gas pass may also have a detrimental eiifect' ongsuperheater operation particularly. when .the superheater: ispositioned adjacent the entrance to the pass as is oftenthecase. On the other hand, uniform distribution .ofgases; toithe passand: across the superheater enables a: maxitube metal.

1 Anobject of my invention is thereforeto provide substantially uniform distribution of heating gases to the heating surface of a boiler unit suchjas described. i I V f Another object of the invention is the provision of upright boiler tubes disposedin. suitable relation to theentrance to a heating gas pass to effect substantially uniform distribution of combustionigas flow into thepass.

An additional object istheprovision of a lim- .ited numberof boiler tubes arranged in a series angularly disposed with respect to the defining wall of a heating gas pass to efiect substantially -uniform distribution of heating gases to the pass ,ina horizontal direction. i

A further object is the method of effecting pass having its entrance disposed at an abrupt angle to the approaching course of flow of such g gases.

Among other objects is the provisionotmeans for. effecting; even distribution of furnace gases to a first boiler heating gas pass while causing .ash or other entrained solids to .be discharged .from the heating gas stream. While baifies forming an angular extension of the partition have been used injsteam boilers of this general type as shown in U. S. Patent 2,186.919, E. Bailey, in such cases the bafile extended across substantially the entire widthof the entrancepasaand functioned. primarily to prolong the flow path of the gases in the furnace chamber and to shield substantially all of the tubes in the first pass from radiant heat. With such constructions the heating gas flow is confined to therelatively narrow space between the endof the partition extension and the rear wall.

A gas throttling effect results which tends to prornotea large eddy current or recirculation efiect across the forward rows of tubes in the first pass.

- j'lihis effect is confirmed by the fact that in the commercial operation of such units, any slag carried by the heating gases tends to deposit on the tubes directlyopposite the gas entrance.

The various features of novelty which characterize my invention are pointed out with particularity in the claim annexed to and forming. a part of this specification. For a better understanding of the invention, its operating advantages and specific objects, attained by its use, reference should be had to the accompanying drawings and biistion chamber H.

, 3 descriptive matter in which I have illustrated and described preferred embodiments of my invention.

'Fig. 1 of the drawings is a sectional elevation illustrating a form of Water tube boiler in which my invention is embodied;

Fig. 2 is a sectional plan of the boiler showrin Fig.1, taken along line 2 2 Fig. 3 is a fragmentary view similar to Fig. 1'

showing an embodiment of my invention in modified form;

Fig. 4 is a sectional plan of the boiler shown v in Fig. 3, taken along line 4-4; and,

Fig. 5 is a fragmentary View, in sectional {plan similar to Fig. 4, showing a further .modifica' tion.

erally of the type disclosed in the aforesaid U. S. Patent 2,186,919 and comprises a setting of rectangular cross section havingupright front and walls 13 and I2, respectively; upright sidewalls l3 and lk'aiid an upper enclosing Wall criteria The space within the setting is divided horizontally by a partition lfi formed of upright boiler tubes-w be later described-the space at one side of thep'artition serving as a [8 receiving hot heatinggases from the com- Bli-Ii'ifS l9 era t pe Suitable for burning the of fuel desires are positioned in the front wall If) for projecting name horizontally through theicombu'sti'on chamber "toward .the'

rear wall [2, the-hot gase -er combustion entering the boiler passage l8 through the entrance opening flier-fried between on'een'd of the -par-' tifibfl l5 and the rear Wall [2. The Spent heating gases are suitably discharged from the boiler passage [8 through a gas outlet, not shown, from a regienadjacent the fldrit Wall ID as discussed for example in the aforesaid patent. I "The boiler structure comprises horizontally disposed upper and lower boiler drums 23'and zteonnectdby a toner tube bank 25 having its nged j'uprignt in rows extending longitu'dir-ially oi-the drums and 24; the embodiment disclosed the tubes have the major tubes a portions of their lengths straight and vertically disposes with their up er ahu lower end p011- tions bent to enter the drums radially.

Each er the setting Walls H), .I 2, ifi jtnd'll lined with fluid cooling tubes Hid, 12a; l-3a,

and 14a suitably cdnnected to the drums 23 and 24, in parallel with'the boiler bank '25, to provide natural eireuiauen sec'uens of'th'e complete boiler circulatory system; the side wen tubes 'l3a-bei ng extended upwardly along the roof 15 to eceneerwan the upper drum 23,an"cl termihating at their lower ends in a header 25 from which connections are made s the sewer drum 24 tissues the floor tubes 21, similar "tothe The boiler unit shown in Figs. 1 and 2&5 gen- Q 4* which extends across-the second and third heating gas passes 32 and 34 from the inner end of the baffle 26 to the front wall 10. r

Tubes 25b of the bank 25 in the first pass 3| are preferably of larger diameter and are more widely spaced, both longitudinally and transversely, than the tubes 250 in the succeeding passes 32v and 34, the tubes 25b being arranged in horizontally spacedgroups to provide an intermediate space 35 for a superheater 36, here shown as being formed of a succession of vertically extending looped tubes 33a having their lower ends connected to inlet and outlet headers Bland 38 respectively; the inlet header 3! being suitably connected to the upper stream and water drum 23 by means of a plurality of longitudinally spaced tubular connectors 39 extend-v ing downwardlyalong the side wall i4 between ;,'coi'nbustionchamber Land the space at the" opposite side a boiler compartment or passage certain of the side wall cooling tubes Ma and thence inwardly between transverse rows of boiler tubesrZBlz. in tlie first pass 3L? -Forwardly of. the superheaterdfi the tubes-of the-:bOiIe'rbank 2fi are'formed in .a group comprising :two'rows of tubes 25b arrangedyand spacedwsubstantially-as the tubes 25b disposed rearwardly of the superheater, and two-rows .Qf

tubes 25d..arranged in staggered relation. toform a well. known pattern. of slag screen rwhereby'i' lcreased entrance areaisprovided for .admi

sion of heating. gases. into the bank 25,.

' The. heating gases. generated in ,thecornbustion chamber 1.1 are first directedlongitudin aliy or the chamber toward. thefiu-id cooled wall I;

at the .rear,..-by reason of the "burners VISbeing positioned in. the front wall l 0, .the. velocityof gas flow being 7 sufficiently high to provide a tendency for the gases to..-maintain their original arrangement sl'r'own in the above mentioned patent.

Transverse baffles 23 and 29 are positioned intermediate the front and rear walls i0 and I2 to provide a plurality of serially connected passes 31,32, and, 34 through which a sub stantiall'y horizontal fi'ow ofheating ases is maintained over the tube bank 25 from the entrance opening 2! into the first pass 3 to the above menuened gas outletleading from the third pass 34.

@ Tubes 25a of the bank-25 are arranged in tube to tube relation to form the partition l6 K direct-ion. of flow beyond the end of thepart t 7, wall 16, with the result that when their tion of flow changes. .touenter. the. first pass 3 l there. is a greater concentration-pf gas flow through theirea'r portion of the entrance opening 2ladjacent thefwall 1.2 than throushthe front. portion adjacent the .transvfllffie, b 1115? 18.

In..order to effect substantially uniformdistrlbution of gas-flow into; the boiler .Qd

across .the superheater 3-6; a .bafiiest uet provided comprising spaced gas deflector units or .bafiies 41 arranged in stepped succession in a row extending .nbliquel'y across the, opening 21 into the first pass .3 I; thebaffle 41a at thefron-t end ofcthb row being positioned adjacent the inner end .Dl the partition wall'IB, and the baflie-fllbzatmfl rear end of the row being positioned adjacent the re'arwall l2 of the combustionbhamber'.

Each of the deflector .bafilesll,"assshown'is formed of boiler tubes lkr, My, andAiehavlng the major portions :of their iengths-straight-and vertically disposed in parallel-relation'to'correr spending straight length portions ofthe boiler bank tubes25b and 25d; the baffle tubeshavi nfi their upper :and lower end portions suitably bent for radial. entrance intothe boiler drums 23 and 24 in cireurnferentialiy spaced longitudinal rows 42 and .JSThe straight leng'th portionsof'the tubes forming each baffle ll are preferably'arirange'diat spacings sufficiently small to provid'e an appreciable directional influence :on thean preaching stream of. heating ases-which to'be guided thereby into the first heating gas asser lfnthe -illustr ated embodiment the spacing is alt aiminimum since the component tubes Mm; Hi}, and 412 are in contacting relation'to provided I b'afiie striicture substantially impervious to g'as flow between adjacent tubes. Suitable-known means, notshown, may be utilizedformaintain- .ing successive baffle tubes in contiguous relation, tor for otherwise.- maintaining eachgroup of tubes m ng/ and 4|z as a unitarygsubstantially continuous. gas deflecting structure. Individual ,baflies 4| may alternatively bev formed by two or more spaced tubes, with suitable closure means provided for the intertube space or spaces. fI'he row of deflector bafiles 4| is inclinedat approximately 45 to the plane of the partition I6, with each. succeeding baflie disposed farther from the plane of the partition than the preceding bafiie; successivelbaiiles being arrangedrat substantially equal .spacings within the row, with theend baffles 4 la and 4 lb arranged at somewhat smaller spacings from the partition and fromthe rear wall [2. The straight length portions of tubes Mr and My of each baflie have their center lines in. a: common plane normal to the longitudinalaxes of the drums and 24, while the tube 412 is displaced forwardly of the common plane at an angle of from 45 to 60 thereto toprovide a-bafiiejl having its leading edge or portion oblique to, the longitudinal direction of flow of the approaching combustion gases.

:-,In,.the specific arrangement shown, each baffle of the series extends outwardly from the opening 2| to a position where its outer edge is at least in.alignment with, if. not actually overlapping,

theinner edge of the next adjacent baffie; for

example, the front tube Me of bafiie Ma and the rear. tube Man of the nextyadjacent battle M are tangentto a common plane parallel to the partitioni ltand to the generally longitudinal directionof flow of the approaching heating gases.

-.Each bafile 4|, which is arranged transversely with respect to the general flow of gases toward the rear of the combustion chamber H, has two distinct effects on gas flow conditions each of which contributes to improved distribution of the gases across the gas discharge opening 2|. First, there is a deflecting action resulting from the transversely extending face of the baffle being impinged upon by a portion of the gas stream flowing longitudinally of the chamber II; this forward, face acting to deflect the major portion of, the gas intercepted thereby and directing that major portion toward the side wall opening 2|, particularly because the outer edge of the baille farther from the opening is slightly upstream with respect to the inner edge adjacent the opening. Secondly, some of the gas that impinges on the outer leading edge of the baffle, as well as gas flowinglongitudinally of the furnace past the outer ,edge of the baflie, expands laterally into the space adjacent therearward side of the baffle whereby a gas eddy is set up which induces a lateral deflection of gas from the stream passing theouter edge of the baflle and thus acts to cause asecond diversion of gas toward the entrance to the gas pass 3|. The same set of actions is repeated with succeeding lateral divisions of the total gas stream by the successively spaced baffles 4|. in the diagonal row. Thus with the gases of combustion more or less uniformly distributed across the width of the combustion chamber between its defining walls I3 and I6, and with the deflection and redistribution of the gases in ad Vance of the opening 2| by the bafiles 4|, an optimum distribution of gas flow throughout the width'of the pass 3| is effected, both with respect to thermal and quantitative characteristics, whereby the entire heating surface of the superheater 36, or other heat exchange surface similarly positioned, may be utilized to its maximum,

closed details of structure havebeen omitted for simplicity of illustration and description. The boiler is represented however as beingof greater capacity, utilizing a greater number of transverse rows of. boiler tubes than in the former embodlment and a correspondingly greater depth of furnace and combustion chamber between the front and rear-walls l0 and I2. The comparative ratios of furnace depth relative to furnace width are approximately, somewhat greater than 1:1 for the unit of Figs. 1 and 2 and somewhat greater than 2:1 for the unit of Figs. 3 and 4. i

. The hot-gases of combustion are projected longitudinally of the chamber ll toward the rear wall 12 as in the former embodiment and due to their relatively high velocity of flow there is a marked tendency for a greater proportion of the gases to enter the first pass 3| through an area adjacent the rear wall |2 than through the remaining area adjacent the transverse baffle 28. The means employed in this instancefor improving distribution of gas flow into the first pass 3|, and across the superheater 36, is a modi fication ofthestructure previously described and comprises a battle 4-5 extending into the combustion chamber I! from adjacent the rear end of the partition wall I6. The baffle also extends beyond the front row of boiler tubes 25d which as shown is substantially in alignment with the row of tubes 25a forming the partition I6.

The bafile 45 is conveniently formed by tubes 45a corresponding in diameter to the tubes 25a of they partition l6, and the baflle constituting,

in effect, an angularly disposed extension of the partition H5. The tubes 45a have the major portions of their lengthsstraight and vertically disposed, similar tothe formation and disposition of other tubes of the boiler; the upper and lower ends of the tubes 45a being suitably bent for radial entrance into each of the boiler drums 23 and 24 in a singlelongitudinal row 48. As shown,

each bafile tube 45a is in contact with the tube adjacent throughout the row, in which relation gasstream, thereby causing the impinging such tubes may be held by suitable means, not shown,

,The battle or deflector 45 is thus positioned in.

the path of the approaching gases where it is impinged upon by a marginal portion of the total -"f. tion to be deflected into the main body of combustion gases and breaking upa part of their velocity head as the gases enter the region fronting the entrance 2| to the first pass 3|. Such impingement and deflection tendsto eiiect substantially complete redistribution of the flowing gases so as to improve both thermal andquantitative distribution throughout the entire gas body before the gases contact tubes of the boiler bank 25. Furthermore, as described in connection with eachbafiie 4|, the flow of gases around the end ofbaiile 4-5 results in the creation of an eddy adjacent the rear side of the bafile which assists in the distribution of furnace gases in a horizontal direction at the side toward the entrance 2|, and thus serves to equalize flow of the gases deflecting structure extending a substantial distance into said stream of rearwardly flowing gases from adjacent the end of said partition without causing any substantial throttling of the gas flow between the combustion chamber and said tube space, and said structure being formed of closely 19 Number up to but not exceeding twenty per cent of the width of said gas discharge opening.

ROBERT K. BEHR.

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

UNITED STATES PATENTS Name Date 2,326,513 Bailey et a1. Aug. 10, 1943 2,415,068 Andrew, Jr. Feb. 4, 1947

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