US2187725A - Furnace structure - Google Patents

Description

Jan. 23, 1940 F. H. BROWN FURNACE STRUCTURE Original Filed Dec. 21, 1922 2 Sheets-Sheet 1 Jan. 23, 1940. BROWN I 2,187,725

FURNACE STRUCTURE Original Filed Dec. 21, 1922 2 Sheets-Sheet 2 Ti: IT i? a I Q,

Patented Jan. '23, 1940 UNITED STATES PATENT OFFICE FURNACE STRUCTURE Francis H. Brown,

Ridley Park, Pa., assignor to The Real Estate-Land Title and Trust Company, Philadelphia, Pa., a corporation of Pennsylvania Original application December 21, 1922, Serial 6 Claims.

of delivering and distributng fuel in a furnace,

whereby to increase the efliciency and the utility of the furnace, it will be readily understood that the invention is not limited to such an adaptation, but finds a wide field of utility for other purposes.

Among the more importantobjects and advantages which characterize this invention, are; the provision of an improved apparatus for conveying and distributing fuel, such as coal and the'like; delivering fuel the fuel evenly in the furnace; the provision of an improved grate structure for furnaces and the like.

It is an important object of this'invention to provide an improved mechanism for sizing and evenly and uniformly distributing the fuel delivered to a furnace, and to this end the invention involves an improved grate bar structure which is characterized by the provision of a grate bar comprising a perforated tube; the provision of a grate bar provided with a plurality of radial apertures; the provision of a series of adjacent hollow perforated grate bars; the provision of an improved form of revolving grate bar the provision of a furnace structure characterized by the provision of revoluble grate bars; the provision of groups of revoluble grate bars; the provision of groups of revoluble grate bars for distributing fuel through the furnace; the provision of a grate bar structure which operates to deliver and distribute fuel to a desired point for consumption and during consumption in a furnace, and for collecting and disposing of ash as formed; the provision of an improved form of grate bar provided with a plurality of series of radially disposed apertures; the provision of an improved revoluble grate bar comprising a cylindrical shell or'tube provided with a plurality of circumferential series of radial openings; and the provision, in a furnace grate, of afseries of parallel perforated revoluble grate bars adapted to rotate in the same direction and at the same speed relatively, for the purpose of distributing'and continuously advancing the fuel delivered'to thefurnace, and

Divided and October 22, 1934, Serial No. 749,433

division of my co-pending, for the purpose of shakingout the resultant ash vantages as may appear 01 partly in vertical to a furnace and for distributing "fire box in order to this application during j its formation. a The foregoing and such other objects and adbe pointed out as this description proceeds are" attained in the struc- 5 tural embodiment illustrated in the accompanying drawings, in which:

partial front elevational view,

section, illustrating equipped with the present invention,

Figure 2 is a vertical, longitudinal, sectional view takengenerally on the plane of line 2-2, of Figure 1, looking in the direction indicated by the arrows;

Figure 1 is a a furnace Figure 3 is an enlarged, transverse, sectional view of the improved gratebar of this invention; Figure 41s a fragmentary, elevational view of thegratebarj Figure his a fragmentary, sectional view'of a modified form of the grate bar;

Figure '6' is a fragmentary, elevational View of the same; '2'

Referring first more particularly to the improved method of stoking a furnace involved in my co-pending applications 3. N. 608,228 now Patent 'No. 1,977,620 and S. N. 749,435, there are included the steps of sizing and depositing continuously a required quantity of fuel, such as coal and the like, in a furnace; then the step of continuously' agitating, conveying, and thus distrib-" uting the 'fuel uniformly'throughout the furnace attain a level fire} and, simultaneously with such distribution and during'consumption of the fuel, removing the ash from the entire area of the fire bed as such ash is formed; collecting, an'ddisposin'g of the resultant ash, thus maintaining in operation a continuously clean, ash free fire. Iii attaining the various steps outlined" above, I provide a structural arrangement which comprises fuel sizing, measuring 40' and depositing mechanism, an improved grate structure, particularly characterized by the provision of revoluble grate bars, arranged in a single group or in multiple groups of any desired T lengths, and an improved ash collecting and-dis: posalmechanism adapted to be operated,con tinuously if desired, with said fuel feeding mechanism and grate.

The improved grate bar herein illustrated and described, while not structures as shown in my co-pending applications above referred to, is particularly adaptable to such use. 7

Referring first to Figures 3 and 4, which exemplify one form of grate bar, I provide a cylina 6 5 limited to use with such i. so that tapered "posed in, longitudinal: rows.

drical shell 5, which is provided with an enlarged axial bore 6, said shell or cylinder 5 being closed by end walls 1, preferably integral therewith. The end walls are provided with polygonal openings 8, and complementally shaped blocks 9 are receivable'insaid openings. 1-,A revoluble shaft I is fixedly connected to the blocks: 9 and extends axially through the shell 5, which may be made in sections of any desired length and then fixedly secured to shaft Ill, said shaft being mountedin suitable bearings H, arranged as will be more particularly pointed out later.

The cylindrical wall of the shell. is provided with radial apertures I2-*l2,"these apertures conveniently being substantially frusto-conical as shown, but they may beofany suitable tapering contour, and having their.;-larger:endspresented toward the axis of the shell. The outer portions of the openings 12 are countersunk as at 13-13, angularly related shoulders lL-Hl are provided thus forming tubes of a general venturi shape. As best seen in Figure 4, the countersunk: portions 13 maywbe substantially square :and the apertures .ofeach circumferential series, such, asA and: B, are .complementally vdis- .The function of this grate bar is to receive the fuel and keep same .constantly-agitated, at the same time propelling and distributingthe fuel" over the fire box-area.

and permitting; a free draft through the grate structure at talltimes. Furthermore, the openings-lZ permit the ash, incourse ofzformation', to drop through-the grate. bar. and-thus prevent fusing or clogging due to clinkering of the ash'on 'the grate. The shoulders ill-l4 serve to provide 1 an uneven: abrasive surface :on the grate .to con- ;stantly :removeethe-zashfrom. partially consumed fuel and thus prevent adherence of-large particles of fuel and-;.insure complete consumption.

Upon reference towEigures 5.:and. 6 'it' will be robserved that I have provided a modified form of the grate bar shown in Figures 3 and 4. --In-this arrangementgthejishell or; cylindrical: bar: is ---providedwith awall thicker:than that of :thecylinder :or shell; 5, :in -other'words-,-the .bore l6 of less ,diameter'rthanjthat of the bore 6. The:shell I5-is provided with a pluralityzof zaperturessimi- .lar to apertures ',l2-:of '-Figure 4 such as-cat lL-l'l. arranged-in circumferential series, but in*. which the aperturesgof adjoining series, such: as C and D, shown-in Figure 6; are :relatively offset ,orstaggered, so; that, insteadof; each unit. of adjacent series-being-in longitudinal rows, 'theeapertures :of alternate circumferential series areiin. a--r ow. This arrangementppermitsgjof: a: finer-'01 iclOSBX disposition ofwthe apertures; and thuspermits of a: greater; number ,of: ,draft-zz penings' toa bar. Howevergt-he grate-bar structure shownrinFigure 3 willigiye; :entirely-satisfactory results; and :the

two bars may-be employed :in conjunction, ras will 1 appear-later.

The apertures H are of the isamezshape -as.:the

- apertures 12 and are :provided withrcountersrmk portions 18 at thcir 'outerrends. ,The: counter- :sunk portions l8, as bestseemin Figure 6; afford tapered shoulders 19, but these shoulders-instead of being right-angularly relatedas :are the Eshoulders M, are disposed at relatively acute angles.

QThexsecuring of-the grate: bar l5 t0=itsishaft 20 "is accomplishedgin a'mannertsimilar to. the manwner .of securingthe: grate bar. 5, to its :shaft' ID, that: is, slidably mounted "thereon; and, therefore,

need not be described here.

;The-grate-barstructure may embody bars of any; desired lengths, and may be assembledin rotation to the grate bars. -some fuels that the bars be placed quite closely may almost touch.

any desired and suitable manner for accomplishing the end for which the same is designed, 'but I prefer to assemble this grate bar structure in a mechanical organization to be presently described. However, the desired results may be attained by arranging a plurality of grate bars similar to those'just described, in a continuous series, and then providing means for imparting It is preferable with afforded between them. It will be observed that 'by "the provision of cylindrical grate bars, the burning surface, or that surface presented toward. the fire bed, is materially increased in area, probably to approximately thirty-three and one-third per cent over that which would be afforded by a grate bar having the same width of burning surface as the diameter of the cylindrical bar. For instance, a cylindrical bar six inches in diameter affords a surface one-third greater .,in areathan that of a flat bar six inches wide. This makes the invention very desirable and valuable where great capacity (fuel consumption) is 'requiredwithin a restricted area, such as in locomotive fmnaces.

Referring now to a simple installation involvingtheimproved grate bar of this invention, it

I will be seen upon viewing Figures 1 and 2 that v.there is provided a furnace structure, which includes a bed or base 2 l, containing an ash pit 22, accessible through the doors 23, and disposed "beneath a gratebar structure, generally desigznated; 24, and constructed in accordance .this invention. The'fire box 125 is provided with the usual end walls; 262 and 21, which support water tubes 28. ,As the boiler structure is not, in detail, essential -.to this invention, it will be referred to but gen- With erally.

The grate structure, as illustrated in Figures l--- and 2, comprises a plurality of the bars 5, herein- ,beforedescribed, the shafts H! of said bars being revolubly mounted in bearings H-H above referred to,- which. latter may conveniently be integrally cast with a supporting base 3! as indicated at -468.

It will be understood, of course, that two of the supporting bases 3i are provided,

- one on either end of the grate carrying shaft H! where this number issufficient to support the only one of which is shown, af-

The base member, as

'P'I'hecarriage formed by the abutments 32, is

mounted on the axles 34 and 35, which are in ,turn carried. by wheels 35 and 31. respectively, said wheels operating on rails 38.

.On-xeach of the shafts Hi there are mounted a -'worm gear 39, said gears meshing with a worm Ml which extends longitudinally of the grate bar structure and above said gears. The worm an is rotatably mounted in split bearings 4i and 42:

carried by the upstanding brackets 13 and 44, which latter, as seen in Figures 1 and 2, are suitably mounted upon the axles 34 and 35.

The split bearing 4| is provided with a pedestal portion 45, to which is fixedly secured a support-l 7t mg bracket member 46. The bracket 46 is provided with a shelf which projects therefrom, and upon said shelf there is fixedly mounted ai driv- 'ing' unit, such as a two-cylinder steam engine 48.

The shaft 49 of said engine carries a worm 5B, which is in meshing engagement with a worm gear 5| fixedly mounted upon anexternal transverse shaft 52. The shaft52 carries a worm 53, which is 'in meshing engagement with a worm gear 5 3, fixedly mounted on the projecting forward end 55 of the screw or worm 40. It will be seen that as the engine rotates shaft 49, motion is transinitted through the worm 5t, gear 5i, worm 53, shaft 52 to the worm gear54, and in turn rotary motion, at a speed, which may be constant or variable, is transmitted to the worm do. Of course, a variable speed electric motor may be employed, or the engine may be provided with a controlling throttle. 'ihe direction of rotation of the worm 40 is such that the grate bars 5 will be rotated in the direction of the arrows E, Figure-2, and thus, fuel which is deposited upon the grate at the forward end, that is, the end near the bearing 4|, will be conveyed toward the rear end of the grate structurein the course of consumption.

It is desirable that the ash which does not pass thro'ughthe'perforations in the grate bars or between the grate bars themselves be finally col-- lected at the rear end of the grate and deposited in the ash pit 22, from whence it may be conveyed by suitable mechanism, To this end, the grate structure is, provided with an outlet space, which space may be adjustable and is generally designated 56, afforded by spacing two grate bars as shown in Figure 2. In order that the ash which is conveyed to this end of the grate structure, be deposited through the space 55, two or more grate bars 51--51 are arranged beyond the bracket 44, and the portion 53 of the screw or worm 40 which engages and drives said grate bars 51, is relatively reversed to the major portion of the Worm 40, and thus the grate bars fi'iwill be caused to rotate in the direction of the arrows F, thereby affording a mechanical discharge of ash through space 56. r

The rollers 63 are adapted to rotate in the direction of the arrow G, Figure 2. v

i It will be observed that fuel is introduced into a furnace by deposition on a grate structure, the latter being composed of revoluble grate bars,

and as these bars are constantly rotated at a de sired suitable speed, the fuel, in course of consumption, is carried from one end of the furnace to the other end thereof. in slight spaced relationship, and as each bar is provided with perforations, the resulting fine ash as formed is therefore constantly removed fromv the fuel bed and deposited in the ash pit 22. The constant agitation of the fuel due to its passage over the uneven surface of the grate bar insures an even distribution of the fuel throughout the furnace and thus affords a level fire in which holes cannot occur. The uneven abrasive surfaces of the grate bars serve to re move the partly consumed fuel from that which is not entirely consumed, and thereby facilitates complete ignition. Furthermore, the larger particles of ash or any fuel which is not entirely consumed, will not pass through the perforations of the grate bars, but will lee-deposited at one end of the ash pit, from whence it may be retrieved for further use. I

A fiue 19a is provided at theforward end of the furnace and affords an exit for distilled gases As the grate bars arev developed during combustion at that end of the furnace, and the resultant coke (fixed carbon) is conveyed toward the rear end of grate, and may be burned at this location, or thence it is deposited through opening 56, and conveyed to a point of utilization.

The fuel feeding mechanism, represented by the rollers 63, serves to distribute the fuel over the entire width of -the grate structure, and thus the fuel is not deposited only in one spot. This is further aided b the provision of the flaring hopper 60.

The grate bar structure may be readily bodily removed by separating the bracket 46 from the front end of the furnace, and running the grate structure out upon the rails 38. A removable wall 38' permits access to the grate in use.

From the foregoing description and the accom panying drawings, it will be observed that there is provided a fuel feeding device or stoker which may be readily adapted to various types of furnaces, and as previously pointed out the provision of the curvilinear grate bar surfaces increases the burning surface of the grate for a given area at least'one-third over that ordinarily attained, and at thesame time, while revolving, does not vary the distance between the bars, which would occur with flat bars. Furthermore, the features of operation and the functions possible of attain--w ment in this invention permit of employment of the device either as a steam generating plant or as a coking mechanism, or permits of employment of the device both as a steam generating plant and as a coking mechanism. The provi sion of the outlet 19a shown in'F'igure 1 permits of the recovery of unburned gases which usually are generated when fuel is first deposited on a they constantly remove ash as formed, so that not only is the fuel properly sized and distributed to maintain a level fire and thus prevent holes, but the fire is always maintained free of ash. Thus, for all practical purposes, no clinkers can form. In all cases the revoluble grate bars or groups of revoluble grate bars may be usedin a level, horizontal plane as shown or at any desired angle therefrom.

The foregoing features are common to all of the forms of the invention described and will be common to any further modifications which employ the revo-luble abrasive grate bars of this invention. These grate bars, being provided with air ducts, afford an even and well distributed area of draft. In fact, by the provision of the flared parts of the draft apertures, best shown in Figures 5 and 6, there is practically one hundred per cent draft area afforded, which further cooperates to prevent the development of cool spots or holes in the fire. This arrangement of the draft openings prevents as plenty of fresh air is always passing through burning of the grate the bars and they are constantly presenting fresh cial and industrial gas manufacturing. This will be clear when it is seen that the device may be readily employed for pre-treatment of the fuel and that the distillates therefrom may enter into the generalcombusticn, or they may be diverted wholly or in part to other uses as desired.

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

l. A tubular grate bar provided on the outer surface thereof with a plurality of intersecting ridges lying in a cylindrical surface and forming a plurality of polygonal depressions, and radial draft openings through the wall of said grate bar in each of said depressions.

2. A grate structure having a plurality of tubular grate bars mounted for rotation in closely adjacent parallel relationship, said grate bars having an outer surface comprising a plurality of intersecting ridges lying in a cylindrical surface and delimiting depressed areas, and frusto-conical draft openings in each of said depressed areas passing radially through the walls of said tubular grate bars.

1 3. A grate structure including a tubular grate bar provided with a plurality of radial apertures in the peripheral wall thereof, said apertures being of a tapering configuration and reducing in area from the inner surface of said tubular grate bar toward a point adjacent to the outer surface, whence the walls of said apertures flare to form intersecting abrading ridges on the outer surface of said tubular grate bar which lie entirely in a cylindrical surface.

4. In a grate structure adapted to convey fuel from an. inlet to an outlet in combination, a plurality of tubular grate bars arranged in parallel closely adjacent relation, and each rotatably mounted upon a fixed axis, the outer surface of said grate bars having a plurality of polygonal depressions forming intersecting ridges which lie in a cylindrical surface, said ridges on adjacent bars cooperating to form a substantially continuous surface, and means for continuously rotating said adjacent bars in the same direction.

5. A grate structure comprising a hollow cylindrical member having substantial wall thickness, said wall having a plurality of regularly positioned apertures therethrough, said apertures extending radially through the wall and being frusto-conical and decreasing in cross section from the inner wall surface to an intermediate wall region and thereafter increasing in cross section outwardly as frusto-pyramids to form a series of polygonal depressions on the outer cylindrical surface of the grate.

6. A grate structure comprising a plurality of hollow cylindrical grate bars mounted for rotation in closely adjacent parallel relationship, each grate bar having a substantial wall thickness provided with plurality of regularly positioned apertures therethrough, said apertures being frustc-conical and decreasing in cross section from the inner wall surface to an intermediate wall region and thereafter extending as frustopyramids and increasing in cross section outwardly to form a series of polygonal depressions on the outer cylindrical surface of the grate bar.

FRANCIS H. BROWN.

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