US2640467A - Heating apparatus - Google Patents

Description

June 2, 1'953 R. c. JoHNsoN Erm.

HEATING APPARATUS 3 sheets-sheet 1 Filed Feb. s, 1948 HEATING APPARATUS R. c. JOHNSON Erm.

INVENTCRS FA YMoN 6.' JMA/50N Bv Cl. C TYMELL 8C. m

June 2, 1953' Filed Feb. s, 194s ATTORNEY June 2', 1953 R. c. JoHNsoN Erm.

HEATING APPARATUS F iled Feb. 3, 1948 3 Sheets-$heet 5.

INVENTORS YMo/vo L'. .of/NsoN BY 135C! C. TYRKELL ATTORNEY Patented June 2, 1953 thence drawingthe'ebnibustionigases"eicngfthe manner, as by welding, bolts, `or otherwise.

.ip1atef34 4closes the top :of thefcombustion :compartment uI II :forwardlyi'of ithe Vfplzane 24,'1wh1e lcpl-ette 35 closes the toprof sad compartment `ite L herrearibfseidpletem. .'rxnroicemhgasinrplfaite provides eomm'i'rriicetien between i.the fumer end of the combustion compartment Il and the fan compartment 23.

The front plate 24 of said fan compartment 23 extends downwardly below the plate 35 of the combustion compartment and forms the rear wall of a channel 31, the front wall of which is designated 38. Said channel walls are joined by a bottom wall 39 and a top Wall 40, the latter being inclined, as shown, if desired, Said channel 23 fits into vertically extending slots 4i, 42 in op-` posite wall portions of the combustion compartment Il and thus communicates with opposite portions of the furnace space containing the fluid medium to be heated. Said fluid medium thus extends into said channel 31 and absorbs heat from the aforementioned channel walls 24, 38, 39, and 40. Said channel 31, as shown, extends adjacent the top of the pile of coal or other fuel in the combustion chamber and insures against active burning of the coal in the top of said pile, notwithstanding desirable preheating of the coal by the passage therethrough of hot combustion gases derived from the burning coal in the lower portion of the fuel pile. By preventing burning of said coal in the top of the pile, spalling may be prevented when said coal descends into the extremely hot combustion zone lower in the pile.

A fan 45 is positioned in` the compartment 23 and is connected to the motor 22. When said motor is energized, the fan is operated to draw gases at high velocity from the combustion compartment Il through the opening 3B into the fan blades, whence said gases are whirled around in the fan compartment. The major portion of the gases pass upwardly through the flue 32, which terminates in a suitable point of discharge outside the furnace. Fly ash contained in said gases is thrown against the curved lower surface 29 of the fan compartment by centrifugal action and passes with some of the gases along said surface, then through an opening 46 between the end of said surface and a baffle 41, thence down between surfaces 28 and 29, and finally out through an opening 48 in the plate 35. Said fly ash is thus returned to the top of the fuel pile in the combustion chamber beneath said plate 35, where air velocities are low.

As the fan rotates, it draws air from below the compartment Il into the lower end of said` compartment and thence upwardly through the burning coal or other solid fuel. The fan is desirably of such capacity, and is driven at suicient velocity, as to draw sufficient air through the fuel to insure substantially complete combustion Within the fuel bed, with little or no combustion outsidesaid bed. In other words, for best results it is preferred that the air drawn through the bed be sufficient for the oxygen therein to be converted in the bed substantially completely,

to CO2, with practically no CO emerging from 'the pile of fuel.

" The hot gases emerging from the top of the fuel bed are drawn upwardly by the fan at high velocity between the walls ll and 38,' then laterally between the plates 34 and 40, and thence through the opening 36 and out through the flue, as above described, the fly ash being returned to the top of the fuel bed where it is mixed with incoming fuel.

As thehot combustion gases travel at high velocity along the inner surfacesof the compartment walls Il, 38, 40, and 34, the rate of heat transfer between said gases and said surfaces is greatly increased, as is also the rate of heat transfer to the uid medium I8 in contact with said surfaces. Also, said gases, as previously noted, exert a pronounced scrubbing action which maintains said surfaces clean and further increases the rate of heat absorption.

In addition, the gases whirled at high velocity in the fan chamber 23 increase the rate of heat absorption through the surfaces 24, 25, 23, 28, and 30. The heat absorption is further increased by the travel of gases through more than one revolution in the fan chamber before they are discharged.

The portion of the gases emerging from the fan casing through the passage 23 is passed on through the opening 48 into the part of the compartment Il which overlies the pile of fuel to the left of the channel 31, as viewed in Fig. 1. As previously noted, the gases which pass through said opening 4B contain fly ash. In addition, said gases contain substantial heat which is imparted to the cold fuel emerging from the conveyor l2, so that this incoming fuel is preheated. Said gases emerging from opening 48 descend into the fuel bed under the pressure existing in the fan chamber 23, and also under the influence of the suction created by the fan in the space to the right of the channel 31 as viewed in Fig. l.

It will thus be seen that the water or other fluid medium I8 receives heat not only through the portions of the compartment walls Il surrounding the fuel which is burning with substantially complete combustion in the fuel bed, but also from the intensely hot gases drawn from the bed and impelled at high velocity along other portions of said walls ll, and also along the walls 38, 40, 34, 24, 25, 26, 29, and 30. An especially effective high rate of heat absorption is thereby achieved.

It will further be noted that these results are attained, in the embodiment above described, by a single fan which not only draws sufficient air through the fuel bed to insure substantially complete coinbustion in the bed, but also impels the hot combustion gases upwardly from the bed at gh velocity along the surfaces above referred If desired, there may be provided studs or bars 50 of efficient heat conducting material, which bars are shown fitted in openings in the plate 34. Said bars, as shown, extend from the interior of the combustion compartment Il into the uid medium I8. These bars provide additional heat absorbing surfaces, extracting further heat from the gases before they reach the fan 45.

In the embodiment shown in Figs. 5-8. the furnace 6D comprises a combustion compartment 6I, open at its lower end and having an intermediate opening 62 for receiving coal or other solid fuel. The fuel may be fed continuously by a screw conveyor into a hopper 63, from which it flows through opening 62 into the combustion compartment. The ashes pass through the bottom of said compartment on to a grate 64, from which they drop into a receptable 65. As in the embodiment shown in Figs. l-4, the fuel extends across the entire cross-sectional area of the lower portion of compartment 3l, so that the walls of the combustion chamber are contacted by burning fuel around their inner periphery for a substantial distance axially of said chamber.

The compartment 6l may be of cylindrical form as illustrated. Its upper end is closed by a suitable cover G6. Said compartment is further provided with an opening 61 for the passage of gases from said compartment into a hor- :mtal fonct for fcliamber 68, fat encierro of fwliich risipo's'itioned th'effan 69.

lciommunicating with fthe `iperiphery .di .the fan -G9iis1an annular :duct or v.passage FH., .formedfby ic'orrcentrio annular shells 112, `lThe fshell l2 :is 'litted int'c fan opening .in the rear wall im fof 'the ifurnace, .and iis :closed at .its outer lend .floyi'a v4:plate 12'.. vThe le' .lindri'cal :shell 1143 ."ifsfisoac'e'd from and supported by the duct 68, through aniar'iniu- YIarlinenilfz'er 'Sift fsnrroundingfsaidtduotasshown. 1

fA't its opposite Lend, said .ishell .13 ris .joined to the casing P4 '12 rin any Asuitable manner, .fas fby aan fend lfolate 115, which A.has ian aopening 175 Vrcommu- -llicting with 'thefduet 'I 'L "lThe-latteris JfOr-ined lof eonverging vWalls land -extends to an opening l'ui (Figs. 6 randf) mnverticaliiue '11 9.. Said 4duet :"l frn'ay lo'e `secured by Welding or fbolts, or in :other :desired 'finannen to 'the nue .t9 fand yktue shells .'ll H53, forlilatel.

"The isha/ft 180 fof the lian shearing .fin the .iolate 12 .fandri's fdrive'n fby fafniotor 535|. "llibre lspa'ce AWithin "the fout'er'f-uriiiaoe Walls, .-'surroundinglthe compartment 1 `Farid duets ta. TH., ian-d Fro, @contains "water :or other .fluid medium to beheated. v

VIn .operation the fan .t9 draws iair upwardly Sironi lbelow .the 'eomlpartltient 6'l in'to itlfieldwe'r fof said fcompalitme'nt and tllei'iee upwardly through the burning fooal or other solid Afuel. -lt twill :of y-fcounse be understood 'that provision iiior the ientrance .of air tiilfough -t'he Aportion of "the .furnace .iloelowfsaid .ic'omp'artrnerit El frneiy readily lb'e .made Thy 'providing 'suitable openings, variable in size if desired, either Ain the door i60" for lels`e yWherefinthe:turnaoeWalls. ills-1in the case of the iran 45, 'the fanta iis spreeraby of fsuch capactty, and is 'driven at su'nicient velocity, Ito 'draw 'enough-Tail' `th-roilfgh the fuel t'o insure substanti'a-lly fcomplete combustion Within the fuel Sbe'd, so that the oxygen in lthe .air `is converted substantially completely to lCO2 Within the bed,`with 269 jpasses through a practically no C0 emerging *4i-rom the 'pile of fuel.'

.ns .the 'hot .gases evolved :from the iburning fuel 'ascend through the upper 'portion `for 'the bed 'under `the zaotion fof the :fan .69, they preheat 'the final-in @theztop ofthe bed. Thehot g'ases emerg ingu-trom :the top of the fuel bed .are 'thence `.draw-'n upwardly by .said fan at high velocity through the .interior of the compartment 61, and vthroufglci the 'interior of the horizontal ."passage 68.. 'Ihe y'gases arethence .impelledoutwardly 'by 'the .ian 'blades yinto the :annular duct or passage It. Under "the :rotary 'action of the fan blades said :gases :are .set into rotation at -high velocity :said duct, 'While at .the 'sanie time they travel longitudinally therein and then pass through opening 16 into the duct TI.. From the latter, said 4gases `pass into the flue 19 iand thence iup- Wardly therethrough toa discharge point 185 out- 'side the-furnace.

Preferably, the gases are introduced tangentially into the llue '19. The particles 'of lya'sh, ythrough 'centrifugal iforoe, zren'iain adjacent the i'cutter portions of the yspace 'Within said ffiue. llhey gradually .settle 'downwardly'.,ithrough {oassage 186 .and opening al., lintothe rashes on 'the grate :and `are carried therewith finto 'the ash receptacle. Thezlue 19 thus serves additionally iasra fly-ash separator.

As an illustration of the speedro'f rotation im `,patted to the gases in the duct "lil, the fan -rotor typical examples may -revolve iait 'speeds .of *from .1725 `to 3450 v.revolutions.per minute, l"orque- -riplreralspeeds 'of from -450'0 to 9.000. The `gases emerging .from :the :fan lperiphery fare 'thus .rei-

ivolvingiatiapproidniatelyithisspeed. Avelocity of'1rot'ation iof ithe 'gasessin the :duet onarliedly iincreases .the litat-fe Iotiheat itran's'ferzto the iiuidfmediumfwhicnsurroundstooth;themuter l:shell 1.2 -and .the aimiez sli'ell .7:3 lof Fsaid mutt. .im 'iadditionthezhigh speedfof travel nftheegases through I:duct Ylili 'itoward the fan lincreas'es fthe rate iof ih'eat transfer between zithat duct tand ithe :fluid :medium surrounding it. increased heat transfer is also obtainedthrough:theiwallsiofithe compartment im above the fuel fbed ias fthegases travel .rat high velocity ffthrough fsaid compartfrn'ent. 'The @fluid medium thus receives heat fait :a yigredtly .increased tra'nsfer rate from :the inotizgases idr'awn :from 'ithe :fuel bed; and 'ithisheit `is fiadditiona'l to that absorbed :by :said :medium .through the portion ofitheconipartment)walls 6| -vllhichisurroundith'eburninglifuel.

It should `ffurzther be noted .lthat `the sheat 'rabe esorption .isiaidition'allyrincreasediby thelfactthdt the gases make several revolutions around the duct for chamber Lf1 :before ithey :fare discharged lth-rough the @outlet vduct .111. This zis :equivalent itozlpassing 4them l:over ia greatersurfacefarea. addition, rsaid ,-gases, `rdue ,to the ifa'n notation, travel through said chamber 'Ilfiniar-spirallpath, which fis equivalent ito ipr'oviv ng them with a greater length :of :traveli'andftime fof icontactftliu's 'further lincreasing fabsorption iof theirsheat As previously ob'served, :thei'heat-absorbing .sur faces are all arranged fso'athatth'eigasesare vooh- .tinuously wiping ithe-m. Thisiislcarriedfnut even into'the nyashseparatoriiniliigsz and 7.. -Itiviill b'e noted that, afs 'thef-"gasesl are 4foroead 'out iof'ithe chamber 'H through duct l'iirito 'iflue '129, *they are fso -directedlinto saidlifiuei-as-to 'spiralaround therein, 'intimately contacting .lits .heat transfer `r`surfaces.

'The terms 'fandennressions f'we :have einh fplvyed faire lus'edias terms fof .description .fandznot 'fof limitanon, iwe have :ino intention, z.v nthe use `of such `rternisfand expressions, of exludine .any equivalents roi the `'features shown :and ideisoribed or fnortions thereof, ibut vfredognlize that y.various Lmodineations iare possible oviithih -.-the scope @of "the invention iclaimed.

We claim:

l. Heatingfapparatus for :burning 'i's'olid fuel to *produeefcombustion 'with su'listantia'lly. no 41'Clo'in 1the `ilfesiultilfi'g gases 'fand I'obtaining 'la 'fhighrat'ellf 'he'a't itr'a'nsfer AIto a illu-id mediiml, said fdmitus comprising Jf-uel-flfeoeivi'ng -elianib'er having "opening-inthe portion thereof' forrecfeiving-tsolid fuel fand 'a'n :opening -Iin yl-another 'fportion for :the Cdisdhanfge ffof :consumed ffuel, Sfsaid ehamb'er libe vtween -lsa'id `lcmenin'gs comprising :continuous '.fuebenclos'ing ``Wall ffor "contacting .Said ffl-el around the I-in'ne'r surface of :said "Wall iand Iconinning said ``f-.ue'l .in A`an elongated e'olunin, means fior continuously Ysupplying .lsolid fuel 'into fsaid Aohaniloer .through said 'reeeivingopeningsandlcom "CurrentlylexertingYalorcethrough said fuel oelfum'n 'upon the `"consumed Iffuel :for feieeting 'the l-'atter through-"said diseharge-foperiingfia'iportion of said fuel-confining wall betWeensaidirec'eivi-Iig vand f'c'is'charge Vlopenings fde'ning a f'combustion yzone `1in fa lportion of said Ifuel fe'olumn confined by Asaid vSinner 'surface :of :said -Wal-1, "'fa'n @means t'for continuously forcing air through `fsa'id @cornfbu'st'ion zone f'in quantity sufficient ffor I-'substan tially comnlete `combustion 5in 'said fuel ibed 'Tand for thence 'for'cihg "the hot gaseous Yproducts@of said combustion through lthe end portion fof s'ai'd 'conned"fuelieolumnireniotei-from:said discharge opening .to -isbject lvincoming 'fresh lffu'el to the heat of said gases, passage means communicating with said fuel-receiving chamber beyond said remote end of said fuel bed for conducting said gaseous combustion products to a point of discharge, and compartment means for maintaining a fiuid medium in heat transfer relation with said fuel column -and with said passage means, said passage means including a chamber containing said fan means vand located in heat transfer relation with said fluid medium.

2. Heating apparatus as defined by claim 1 wherein said chamber containing said fan means has an arcuate wall adjacent the blades of said fan means whereby gases are impelled by said fan means over said wall with a rotary motion before discharge of said gases from said chamber.

8. Heating apparatus as dened by claim l, wherein said fan means draws air and combustion gases through the fuel bed countercurrent to the travel Aof the latter in said fuel-receiving chamber.

4. Heating apparatus as defined by claim 1, wherein the space enclosed by said fuel-enclosing wall is of substantially uniform cross-sectional area between said fuel-receiving and fuel-discharge openings.

5. Heating apparatus as defined by claim 1, wherein the fan means draws air into the fuel bed in the direction of the longitudinal axis of said bed, and also draws combustion gases through said bed in said direction.

6. Heating apparatus as defined by claim 1, wherein said passage means comprises portions extending upwardly and laterally from said fuel receiving chamber.

'7. Heating apparatus as defined by claim 1, wherein said passage means has a portion extending upwardly from said fuel-receiving chamber for receiving gases emerging from said remote end of said confined fuel column and also has a lateral extension communicating with the upper end of said upwardly extending passage portion, said fan means is in direct communication with said lateral extension, `and said passage means also has a portion for receiving gases through said fan and directing said gases to a gas discharge opening.

8. Heating apparatus as defined by claim l, wherein said passage means has a portion extending upwardly from said fuel-receiving chamber for receiving gases emerging from said remote end of said confined fuel column and also has a lateral extension communicating with the upper end of said upwardly extending passage portion, and wherein the chamber for said fan means is provided at an end of said lateral extension and in communication therewith, and a vertically extending passage has its lower end in communication with the top of said fan chamber and extends Ito a gas discharge opening, said fan means being located in the last-mentioned chamber for drawing gases through the first mentioned passage means and thence impelling them through the last mentioned passage to said gas discharge opening.

9. Heating apparatus as defined Aby claim 1, wherein said passage means has a portion extending upwardly from said fuel-receiving chamber for receiving gases emerging from said remote end of said confined fuel column and also has a lateral extension communicating with the upper end of said upwardly extending passage portion, and wherein the chamber for said fan means is provided in communication with said lateral extension, a second lateral passage being provided which surrounds the lateral extension of the first named passage means and formsan extension of said fan chamber, and said fan means being located in said fan chamber for driving combustion gases through said first mentioned passage means and thence impelling them through said second lateral passage towards a gas discharge opening communicating with said second lateral passage.

10. Heating apparatus as defined by claim 1, wherein said passage means has a portion extending upwardly from said fuel-receiving chamber for receiving gases emerging from said remote end of said confined fuel column and also has a lateral extension, said compartment for containing a iiuid medium surrounding both said upwardly extending portion and said lateral extension of said passage means, said chamber for said fan means being in communication with said lateral extension, a second lateral passage being provided which surrounds the lateral extension of the first mentioned passage means and forms an extension of said chamber for said fan means, said second lateral passage being in communication with a gas discharge opening.

11. Heating apparatus as defined by claim l0, wherein said second laterally extending passage surrounding the first mentioned laterally extending passage is spaced therefrom, and means are provided for maintaining a fiuid medium in the space between said laterally extending passages.

12. Heating apparatus as defined by claim 10, wherein fly ash receiving means communicates with said second lateral passage.

13. Heating apparatus as defined by cla-im 8, wherein other passage means are provided for conducting iiy ash from said fan chamber and baie means are provided between said other passage means and said vertically extending passage for diverting fly ash into said other passage means.

i4. Heating apparatus as defined by claim 1, wherein said passage means has a portion extending upwardly from said fuel-receiving chamber for receiving gases emerging from said remote end of said confined fuel column and also has a lateral extension, a second laterally extending passage being provided which surrounds the first mentioned lateral passage, said fan means being positioned for driving gases through said upwardly extending passage and the first mentioned lateral passage and thence impelling said gases rotatively into said second lateral passage, and said compartment means for the fiuid medium maintaining the latter in heat exchange relation with both said laterally extending passages and said upwardly extending passage.

15. Heating apparatus as defined by claim 14, wherein the second laterally extending passage is in communication with the periphery of said fan for receiving gases impelled rotatively from said periphery.

16. Heating apparatus as defined by claim 1, wherein said fan means is interposed between portions of said passage means for continuously drawing air into said fuel bed and thence drawing the resultant combustion gases into one portion of said passage means and causing said gases to travel spirally in the other portion of said passage means.

17. Heating apparatus as defined by claim 1, wherein said fan means is interposed between portions of said passage means for continuously drawing air into said fuel bed and thence drawing the resultant combustion gases into one por- RAYMOND C. JOHNSON. CECIL C. TYRRELL.

References Cited in the file of this patent UNITED STATES PATENTS Number 5 Re. 22,793 1,561,898 2,216,809 2,340,431

Number Name Date Satchwell Sept. 17, 1936 Antisell Nov. 17, 1925 Derby Oct. 8, 1940 Satchwell Feb. 1, 1944 FOREIGN PATENTS Country Date Great Britain Nov. 11, 1935 Great Britain June 2, -1936 Great Britain Oct. 1, 1936 Great Britain Oct. 8, 1936

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