US2526416A - Water-cooled furnace - Google Patents

Description

' 2 sheets-sheet 1 G. A. REHM WATER-COOLED FURNACE Oct. 17, 1950 Filed Aug. 8, 1947 oct. 17, 195o G. A, REHM 2,526,416

WATER-(zoomen FURNACE Filed Aug. 8, 1947 2 sheets-sheet 2 @www Patented Oct. 17, 1950 In"WATER-#C0OLED EURNACE I.'@tust-av.ArRehm,eWorcesteir, Mass., `assigner to 1. Rileytoker f Corporation, 'Worcesterj- Mass., a

corporation of'Massachusetts i Application vAugust 8, 1947,.,,Seriailotfl This invention relates towater cooled furnaces,

i and more particularly to the construction and arrangement of hopper bottom furnaces forrthe combustion of pulverized coal orsimilar fuels in suspension.

It has been proposed heretoforerto construct the lower portion of a furnaceV in the form of a V in longitudinal cross section, the front and rear walls of the furnace -bottom converging downwardly toward a transverse slot or opening through which thefuel ash is discharged. The

y side walls of such furnaces are usually provided With upright water wall tubes,.but in general it .has not been considered feasible to extend these i tubes downwardlyinto the Vrshaped portion of the. furnace, primarily because of the` difculties involved in supplying water. to the tubes. Consequently, the side walls ofthe hopper bottom v1. have ordinarily been constructed ofbrickwork Without water cooling, Aand this has resulted in excessive air infiltration and .highmaintenance l walls thereof.

It is a further object of the invention to prov vide a hopper bottom furnace in which the side walls of the main combustion chamber, as well as the side walls of ther hopper bottom, are adequately cooled by water tubes.

It is a further object of the invention to provide, a simple and relatively inexpensive construction for a hopper bottom furnace, in which the side walls are cooled by `water vtubes and the need for brickwork is avoided.

It is a further object of the invention` to provide a hopper bottom furnace having a new and advantageous arrangementv of Water tubes for cooling the various Walls, and a highly effective downcomer system for supplying water to the tubes.

With these and other objects in view, as will be apparent to those skilled inthe art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention', and in which like reference numerals indicate like parts,

Fig. 1 is a longitudinal sectional view of the lower portion of a water cooled furnace, the section being taken on thek line I-I of -Fig. 2;

Fig. 2 is a section taken on the line 2-2 of 4Fig; 3` is al section taken on the line 3-3' of j Fig. l and Figl Il;A is a fragmentary plan View taken as L `indicated by the line lei-li of Fig. 1.

5 f They embodiment illustrated comprises a furnace or combustion chamberj It having a front "wall II, a rearwall I2, and two side walls' I4, th'efront Wall having'an opening" I5 therein vfor Vtheintroduction "of a suitable fuel, such as m pulverized coal, which is burned in suspension. f- 'At the rear ofthe combustion' chamber there is f `mounted a `transverse horizontal water drum I6 from which a bank of convection water tubes f I8"ert e'nds=rv upwardly. An` upright b'aliefii is 1"5'mounted'at' the front`of thetube banlrl to deflect" the" furnace gases upwardly in a wellknown mannerf''he usual soothopper '2Q is ff-provided behind the drum? Ii to collect particles of soot orfash'- which may be carried rearwardly 20" over'- the top ofthe bale i9.

The lower vp'ortion'of the combustion chamber Il) is shaped tof'provide a hoppe'rbottomwhich will' collect anddi'scl1argev the`ash^which is deposite'dftherein)from the `burning fuel'.` lFor this 25 purpose a reawb'ottomwall 22 slopes ldownwardly and `forvl/'ardlyf'from'ther loweri marginof the "rear wall i2,'and afrontbottom wallt slopes downwardly and rearwardlyV fromthe lower marginiof' thevfront'w'all iIf'Th'e lower portions gf, 'of the'sloping w'alls'22VV and 23k are separated by a comparatively..narrowY "transverse slot '24 through'whiclrthe"ashes maydrop into an ash pit 26 therebeneath-These lsloping'vvallsextend between th'e'sideiwalls'A IQ." An'access ldoor openrg' ing 2l' is provided inone" of'the'side walls, somea what above theslotZt.

G'The: upper surface of the sloping rear iwall i? 22of the hopper isi protected fand" cooledv by 4rrsmeans'of a'row.' of inclined water tubes 29 which de: are connectedat their-lower ends to a transverse 'fhorizontal header" 3i] located adjacent to 4the :.f-f-lowerfedge of'rthe Wall; ;These;tubes extend up- 1: wardly valong-.the rear wallV I2 :and thebaille I9. )TeInf orderthat'-A an adequate supply of rwater .may Is-be deliveredto. the vheadert;Y this header is connected to the water drul'nf.v It by. means of a '.:trowofrtdowncemerl tubes 3i: located. slightly to the-rear of the .tubes 2 9. ffihe upper surfaceof the? sloping front wall 50-` 23 of the hopper is protectedand cooled by means ofv a `rowi of inclined-.water tube'sl 'whichv are 'nconnectedattheir lower'A ends -to a v transverse .-'rrzhorizontal header 3%. located adjacent thexlower edge of thefrwalh fThese tubes'extendvupwardly halon'gfthe ffrontwialli II.`1 lnworderthat: an adefxquatersupply of vwaters'mayY be deliveredto the header 34, its ends are connected to the adjacent ends of the rear header 30 by means of horizontal headers 35. It will be apparent that the headers 3B and 34, in conjunction with the two headers 35, form a header structure of generally rectangular shape which surrounds the ash discharge slot 24.

Provision is made for protecting and cooling the side walls I 4. For this purpose a row of spaced water tubes 31 is provided adjacent each side wall. The lower ends of the tubes I31 are connected to the headers 35. and the tubes extend upwardly along the inner surfaces of the side walls l ll. These tubes are relatively few in number and comparatively widely spaced, but they are sufficient for the protection of the lower portions of the side walls of the hopper, which are not subjected to very high temperatures in service. Certain of these tubes are bent laterally to avoid interference with the door opening 21. The upper portions of the side walls I4 require additional protection, and accordingly other upright water tubes 3B are arranged to extend along the inner surfaces of these walls. The lower ends of the tubes 3B adjacent each wall are connected to a horizontal header 39 which is located an appreciable distance above the corresponding header 35 but preferably somewhat below the tops of the sloping walls 22 and 23. Each header 39 is positioned at the outer side of the corresponding group of water tubes 31. 'Ihe tubes 38 are preferably located in a common plane with the tubes 31, except for the end portions of the tubes. which are bent to enter the headers. As best shown in Fig. l, the tubes 38 adjacent to the -central portion of each side wall are widely spaced and alternate with the tubes 31, whereas the tubes 38 adjacent the front and rear portions of the wall are closely spaced. Thus the portion of the wall above the header 39 is protected throughout by closely spaced tubes certain of which extend downwardly to protect the lower portion of the side wall of the hopper.

The headers 39 are adequately supplied with water by an independent downcomer system. For this purpose these headers `are extended rearwardlv, and a row of tubes 4I connects the drum I5 with the rear portions of the headers. The tubes M are located behind the tubes 3|, and they are bent laterally (as best shown in Fig. 4) to connect with the headers.

The operation of the invention will now be apparent from the above disclosure. The water tubes 29, 33, 31 and 3S will absorb heat which is radiated from the combustion flame, and some of the water in these tubes will be changed to steam. This will produce an upward flow of the steam and water mixture in these tubes. Water will ow downwardly through the tubes 3l from the drum I6 to the rear header 30, and thence forwardly through the lower side headers 35 to the front header 34. Thus the lower ends of the tubes 29, 33 and 31 will be supplied with water. Water will also flow from the drum I6 downwardly through the tubes 4| to the rear portions of the upper side wall headers 39 and thence forwardly through these headers, thereby supplying water to the lower ends of the tubes 38. Thus an adequate supply of water will be provided for all of the heat exposed tubes, a rapid circulation will be ensured, and there will be no possibility of a reverse iiow in any of the tubes.

The construction is comparatively simple and inexpensive. The side walls of the hopper bottom are eiectively water cooled, and no brickwork is required in their construction.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A water cooled furnace comprising two opposed upright side walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal lower header located adjacent the lower margin of each side wall, water wall tubes extending upwardly from each of said headers, a substantially horizontal upper header located an appreciable distance above each lower header and at the outer side of the corresponding water wall tubes, other Water wall tubes extending upwardly from each of said upper headers, and downcomer means to supply water to all of said headers.

2. A water cooled furnace comprising two opposed upright side walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an .ash discharge opening, a substantially horizontal lower header located adjacent the lower margin of each side wall, a substantially horizontal upper header located an appreciable distance above each lower header, closely spaced upright water wall tubes associated with the side walls above the upper headers, certain of the said tubes being connect-ed at their lower ends to the upper headers and other` of the said tubes extending downwardly past the inner sides of the upper headers to connect at their lower ends with the lower headers, and downcorner means to supply water to all of said headers.

3. A water cooled furnace as covered by claim 2, in which one of the side walls is provided with an access door opening located between the corresponding upper and lower headers, and certain of the downwardly extending tubes are bent laterally to avoid interference with said door opening.

4. A water cooled furnace comprising two opposed upright side walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal lower header located adjacent to the lower margin of each side wall, a substantially horizontal upper header located an appreciable distance above each lower header, upright water wall tubes sociated with the side walls above the upper headers and connected at their lower ends to the upper headers, the tubes adjacent to the central portion of each side wall being spaced apart more widely than the tubes adjacent to the front and rear portions of the side walls, other upright water wall tubes located between the said more widely spaced tubes and extending downwardly past the inner sides of the upper headers to connect at their lower ends with the lower headers, and downcomer means to supply water to all of said headers.

5. A water cooled furnace comprising two opposed uipright side walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal lower header located adjacent to the lower margin of each side wall, a substantially horizontal upper header located an appreciable distance above each lower header, closely spaced upright water wall tubes associated with the side walls above the upper headers, alternate tubes adjacent to the central :portion of each side wall extending downwardly past the inner sides of the uppei headers to connect at their lower ends with the lower headers, the remaining tubes being connected at their lower ends to the upper headers, and downcomer means to supply water to all of said headers. Y

6. A water cooled furnace comprising two opposed upright side Walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal lower header located adjacent to the lower margin of each side wall, a substantially horizontal upper header located an appreciable distance above each lower header, closely spaced upright water wall tubes associated with the side walls above the upper headers, certain of the said tubes being connected at their lower ends to the upper headers and other of the said tubes extending downwardly past the inner sides of the upper headers to connect at their lower ends with the lower headers, a substantially horizontal header located adjacent to the lower margin of each of said sloping walls, water tubes extending upwardly from each of the last-mentioned headers and along the ycorresponding sloping wall to cool the same, and downcomer means to supply water to all of said headers.

7. A water cooled furnace as covered by claim 6, in which the ends of the said last-mentioned headers are connected to the ends of the lower side wall headers to form a header structure of generally rectangular shape surrounding the ash discharge opening. v

8. A water cooled furnace comprising two opposed upright side walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal header associated with each side wall and located an appreciabledistance above the ash discharge opening, upright water wall tubes associated with the side walls above the headers, certain of the said tubes being connected at their lower ends to the headers and other of the said tubes extending downwardly past the inner sides of the headers to cool the lower portions of the side walls, downcomer means to supply water to the headers, and other downcomer means to supply water to the lower ends of the said downwardly extending tubes.

9. A water cooled furnace comprising two opposed upright side Walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal upper header associated with one side Wall and located an appreciable distance above the ash discharge opening, upright water wall tubes associated with the said one side wall above the header, certain of the said .tubes being connected at their lower ends to the header and other of the said tubes extending downwardly past the inner side of the upper header to cool the portion of the side wall therebeneath, a lower header to which the lower ends of the said downwardly extending tubes are connected, downcomer means to supply water to the upper header, and other downcomer means to supply Water to the lower header.

10. A water cooled furnace comprising two opposed upright side walls, two opposed sloping bottom walls extending between the side walls and converging downwardly toward an ash discharge opening, a substantially horizontal upper header associated with each side wall and located an appreciable distance above the ash discharge opening, upright water wall tubes associated with the side walls above the headers, certain of Vthe said tubes being connected at their lower ends to the headers and other of the said tubes extending downwardly past the inner sides of the headers to cool the lower portions of the side walls, inclined water tubes associated with each of the said bottom walls, lower header means adjacent to the ash discharge opening, the lower ends of the said downwardly extending tubes and of the said inclined tubes being connected to the lower header means, downcomer means to supply water to the upper headers, and other downcomer means to supply water to the said lower header means.

GUSTAV A. REHM.

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

UNITED STATES PATENTS

Images