US1732497A - Fuel grate - Google Patents

Description

0d:D 22, 1929. J, J, BUCKLEY 1,732,497

FUEL GRATE original Filed March 17. 192e;

Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE JOHN J. BUCKLEY, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO FIREBAR CORPORATION, OF CLEVELAND, OHIO, A CORPORATION OF DELAWARE FUEL GRATE Application filed March 17, 1926', Serial No. 95,265. Renewed June 21, 1928.

l This invention relates to certain improvements in fuel grates and, more particularly to fuel grateswhich are primarily designed for the combustion of the more finely divided forms of fuel, such as pea7 and buckwheat anthracite coal, screenings and the various forms of bituminous coal.

In the combustion of coal, one of the greatest sources of loss of heat-units arises from failure to supply sufficient air or oxygen to all parts of the fuel mass, so that conditions which approximate tocomplete combustion may be secured of the gases which are driven off and of the carbon content.

lVhile the more finely divided forms of coal may be burned With greater' economy and efficiency than the larger sizes, so far as I am aware, prior to my invention, no fuel grate has been produced which will both effectively support the finer formsof coal and will, at the same time, permit air to be supplied' in suficient volume to all parts of the fuel mass to secure even approximately complete combustion thereof. This failure to supply sufticient air to all parts of the fuel mass is largely due to the fact that, while ordinarily approximately one half the total area of a grate surface is open for the passage of air, in grates which are almost universally used the solid portions haveflat top surfaces on which thev fuel rests and over which the air is prevented from passing by reason of the vclose contact of this fuel with the grate surface, so that, while air may be supplied in sufficient quantities to fuel directly over the grate openings, it is insufficiently supplied to the other portions of the fuel. Moreover, these grate openings tend to cause concentrated air jets to be directed up through the fuel, which tend to cause holes in the fuel mass, the formation of uncombustible slag and clinkers, and` what is more objectionable, overheating of the grate bars, resulting in warping and burning away the iron of which they are formed.

The objects of my invention are to provide a. form of fuel grate which is adapted to support the finer sizes of coal untll consumed and which will not permit the passage of unconsumed coal therethru to an appreciable extent, and will, at the same time, support the coal in a manner to permit air to be conducted to all portions of the fuel mass at the bottom thereof, or at the top surface of the grate, so that air will be supplied to all portions of the fuel in quantities sufficient to secure practically complete combustion thereof. Also to provide a grate which is so constructed that the air passing therethru will have a cooling action thereon and will prevent overheating of any portion thereof.

I accomplish these objects by providing a form of fuel grate which comprises a series of bars each of which is provided at each side thereof with a series of upwardly tapering projections which extend above the top surface of the bar and have fuel supporting faces at their upper ends, said projections being mount-ed on laterally projecting lugs, fins or flanges which are formed on the sides of the bar and extend downwardly from its top surface for a substantial distance, or to, or nearly to the bottom side thereof, said projections and lugs being cast integrally with the bar, and the fuel -being supported above the level of the top sides of the bars, or on the tops of said projections, so that air passing upward between the bars and the lugs on the sides thereof, will pass over the tops of the bars between the projections and upward thru the fuel and will be diffused thruout practically the whole mass. At the same time, heat imparted to the projections, which might be excessive in amount by reason of the direct contact of the fuel therewith, Will be conducted to the lugs on the sides of the bars and this heat will be radiated therefrom and taken up by the air passing upward between the lugs and bars, thereby preventing overheating of any portion of the grate.

For a more complete understanding of my invention reference is made to the accompanying drawing in which:

Fig. 1 is a plan View ofa stove or furnace grate embodying my invention. Y

Figs. 2, 3, 4 and 5 are sectional views at lines 2--2, 3 3, 4-4, and 5 5, respectively of Fig. 1.

Fig. 6 is a fragmentary View of the grate in perspective.

According to m invention I provide a frame 10, which, or a stove or small furnace, will be made to lit the bottoml of the fire box,and be supported therein in the usual manner, the frame, in the present instance being shown in rectangular form. The entire inner edge portion of the frame is provided with a series of integral, inwardly, and horizontally extending lugs 11, which are regularly spaced apart, providing internediate vertically extending passages 12. An upwardly extending rib 13 is formed integrally with the frame and extends continuously about the saine at the ends of said are spaced equall passages. Said lugs 11 are each provided with an integral, upwardly extending, cubically shaped projection 14, having aflat, horizontally disposed face 15 at its upper end, the faces 15 being all disposed in the same horizontal plane. A groovek or horizontal passage 16 is thus formed between the rib 13 and each projection 14, which opens at its inner side to each passage 12 between the lugs 11. The width of the passages 12 is preferably slightly less than the width of said lugs and projections.

The grate, which is adapted to be mounted inthe frame 10, comprises a middle longitudinal bar 17, on the ends of which trunnions 18 and 19 are formed, the trunnion 18 being indicated as supported on some part of the stove or furnace, and the trunnion 19 in the4 frame 10,' permitting the grate to be turned to a Vertical position. The grate .also comprises two longitudinal edge bars 20 and series of-parallel cross bars 21, which or arranged at regular intervals from en to end of the grate. All

' of said bars are cast integral with each other at their points of intersection, and the upper Asurfaces thereof are disposed in the same horizontal plane. Said edge bars 20 and cross bars 21 are provided with a regular series of pairs of transversely or vertically extending lugs, fins or flanges 22, 26, 27 which project laterally from each side thereof in directly opposite relation, andare cast integrally therewith, and each lug has an integ`ral. trunco-pyramidall -shaped vprojection 23 extending vertically rom the upper portion thereof and directly thereover, three of the sides of each projection being continuous with the corresponding side of the lug, and

lthe fourth side extending from the up er surface of the bar adjacent its edge, so t at a space is provided between the adjacent sides of each pair of pru"ections ap roximately equal tothe width o thebar. Said projections are extended above the upper surfaces of the bars a distance, in practice, approximating to the width of the bars, although this distance will be varied according to conditionsto be provided for, and the upper ends thereof are flat, so that a fuel-supporting face 24 is provided on the upper end of each projection, said faces being disposed in the same horizontal plane. Said projections 23 are regularly spaced and arranged in line, both longitudinally and transversely, with each other and with the projections 14 on the frame, so that the width of the spaces between the sides of adjacent lugs, and between the ends of adjacent lugs on adjacent bars, are uniform and approximately equal tothe spaces between the lugs 11 on the frame.

As shown in the drawing, the maximum cross sectional area of the lugs 22, 26, 27 and projections 23 is at the level of, or closely adjacent the level of the top side of the bars and the sides of said lugs converge downward from this level to their lower ends and the sides of the projections 23 converge upward from the same level to their upper ends. The sides of the bars also converge froln top to bottom. This tapering formation is a practical necessity in forming the entire grate construction in a single integralY casting, as shown, the grate being molded from two patterns in separate flasks, the bars and lugs being molded in one flask and the projections 23 being lnolded in the other, and the construction permitting each pattern to be drawn from the moulding sand, so that when the flasks are placed in together in register these portions may be cast in one piece.

The frame 10 is also similarly formed, and is cast in a similar manner, the frame proper and the lugs 11 thereon having their sides tapering downward from the top surface of the frame and the rib 13 and projections 14 having their sides tapering upward from said surface. The above described tapering formations of the side lugs and projections have, however, important advantages in the practical operation of the grate, as hereinafter described.

With the above described construction, an upwardly extending air passage is provided on three of the sides of each lu and the projection thereon, except when t ese passages are partly obstructed by the intersection of the longitudinal bars with the cross bars. A horizontally extending passage is also provided between each pair of projections, so that each fuel-supporting face 24 is separated from each adjacent face either by an air passage which leads directly `from the ash-pit, or by a passageover the bar, which opens directly to such a passage at both'ends and at both sides. Consequently air will be supplied to the fuel sup orted on each face 24 at. all sides thereof, an will, therefore, be directly supplied to all portions of the fuel body. Ash collecting on the faces 24, or on the upper surfaces of the grate bars, will readily slide therefrom into the adjacent air passages and fall into the ash pit, so that the passage of air over the bars between the projections is unlikely to be blocked with ash to an extent suff'r cient to interfere with thedesired distribution of air beneath the fuel mass, a slight jarring action on the grate usually being sufficient to dislodge the ash and cause it to fall thru the passages between the side lugs into the ash pit, and, as these passages increase in transverse area from the level of the tops of the bars downward,'clogging thereof with ash is unlikely to take place. While, in practice, much of the fuel may be of such size that it will be possible for it to fall thru the air passages unconsumed, yet, on accou t of the fact that the grate surface is broke by the projections, there is a greater tendency for the pieces of fuel to become wedged together, and vto arch over the passages, as indicated in Fig. 3, than if the entire 4 same level.

As the fuel is 'fthus practically entirely supported by a relatively large number of f small faces, each of which is` separated from the next by a passage thru which air is ordinarily free to pass, the air will be practical-v ly uniformly distributed throughout the entire `area of the grate and, therefore, beneath the entire fuel mass, and as the air will pass upward thru the fuel practically uniformly in all portions thereof correspondingly uni form combustion will be'v secured throughout the -entire fuel mass, and over-heating at certain points by the well known blow torch effect of large grate openings will be` avoided. Also as the fuel is supported by the projections 23 out of direct contact with the grate barsthey do not become over heated and warpedor burned out.

While the top faces ofthe projections 14 and 23 are in direct Contact with the fuel and there-is,'in consequence, a tendency to cause theirto-p portions to be over-heated,

this tendency is effectively counteracted, as the construction permits the air passing up between the bars and lugs to pass about all sides of said projections,` so that heat radiating therefrom 'will be imparted to the air `and carried upward to the fuel. Also, as

*said projections taper or decrease in cross sectional areaA from the tops of the bars upward, and the heat from the fuel is primarily imparted directly to'theirupper ends, the mass of metal provided to conduct the heat from the top .endsof-the projections is greater than the mass to which the heat is directly imparted-.so that'the heat is con;

ducted to the gratep'ortions on which the projections areformed, vpractically as rap'- idly as it is imparted .'thereto, under ordinary conditions. Accumulation of heat in the top portions of these projections is thus -prevented by providin an increasing cross sectional areaof meta 'for conducting the heat from these portions,l and 'this heat is in turn conducted to the' side lugs `on 'which grate surface was at the they are mounted, and also, to some extent, directly to the bars. The lugs, which receive'the greater portion vof the heat imparted to the projections, are in turn effectively cooled by the air passing upward, in most instances, at three of the sides thereof, the air taking up the vheat radiated from lugs. The heat imparted to the bars will also bc absorbed by the air in like manner, so that the whole grate will be effectively cooled, or `be kept from being overheated by the air which is drawn, or forced up thru the grate to support combustion. The air will in this manner also be effectively pre-heated before it becomes mixed with the gas from the fuel, so that the efficiency of combustion will be thereby greatly increased. Vv'hile there is a practical limit to the extent to 4which it is desirable to have theprojections 23 extend above the level of the top of the grate bars, the extent indicated in the drawings is desirable, but may be somewhat varied according to conditions.

As the adjacent sides of the lugs on the sides of the bars diverge from the tops of the bars downward, the 'air passages there-A between are contracted as they extend -upward. so that the air is somewhat concentrated into jets at the points at which it is delivered to the fuel, and theseujets are immediately diffused or expanded beneath the fuel lbetween the projections 23 and over the top sides of the bars. As the sides of the projections 23 converge as they Yextend .upward from the-tops tof the bars, and the Itops of the projections are. small, they ash rate of fuel combustion is secured, with a corresponding increase in evaporation capacity, this being principally dueto the greatly'increased volume of air which is supplied to the whole fuel mass. lA relativelyl igh heat is, in consequence, secured at the surface ofthe fuel mass, with the further result that material carrying a low percent-4 age of carbon is disintegrated and materials carrying' no carbon, -s'uch as slate, are highl heated, sojthat as these'materials smk dyown close to' grate and the `relatively cool air comes in contact therewith,they crumble, so that they pass readily thru the grate.

- The 'combustion materials in the fuel are* practically entirely consumed, as the *perlis " The formatlon of clinkers isalmost entirelyprevented for similar reasons. 4 y

las

centage of unburned combustible `in the ash l is found to be inconsequential, being confined to small particles which fall thru the,- grate. l 2 1 lac In consequence the grate becomes freed from noncombustible material, either automatically, or by a slight jarring action on the grate, so that dumping or otherwise cleaning the grate is only necessary after long periods of use.

The construction shown permits the grate to be tilted, to shake it, or dump the fuel thereon, but it will be understood, however,

that my invention is not necessarily limited 'o dumping forms of grates, but may be employed in connection with grates of other types.

I claim:

1. A fuel grate comprising aseries of suitably spaced horizontally dis osed bars, each bar having a series of suitalbly s aced lugs projecting laterally from one si e thereof, to provide vertically extending air passages between the "adjacent sides of the lugs at the side of the bar and between the ends of the lugs and the next adjacent bar, each of said lugs being extended above the level of the top of the bar and having fuel supporting faces cnl their upper ends.

2. A fuel grate comprising a series of suitably spaced horizontally disposed bars, each bar having a series of suitably spaced lugs projecting laterall from Aeach side thereof,

ao t0 prov'dz vertice. ly extending air passages at each side of the bar between the adjacent sides of the lugs and between the ends of the lugs and the next adjacent bars, each of said lugs being extended above the level of the top i of the bar and having fuel supporting faces on their upper ends.

3. A fuel grate comprising a series of suitably spaced horizontally dis osed bars, each bar having a series of suitaibly s aced lugs o projecting laterally from one si e thereof and extending from the bottom to the top of the ba1`,.t`o provide vertically extending air passages at the side of the bar between the adjacent sides of the lugs and between the 5,endsof the lugs and Itnenextadjacent bar, each of said lugsbeing extended above the level of the top ofthe bar and having fuel supporting faces on their upper ends.

. 4. A fuel grate comprising a seriesv of suitablyspaced horizonta ly di osed bars, each vbar havinga series of suita ly spaced lugs A projecting laterally from each side' thereof and extending vertically from the bottom of the' barto a level above the level of the top of the bar and having fuel y,supporting faces at their upper ends, to rmit the freecirculation o air between t e adjacent sides of the lugs and between the end s of the lugsv and the adjacent bars thereby totake up heat 6o conducted from the top ends of the lugs to their lower portions.

5. A fuel rate com rising a series of suitably spaced iorizonta ly disposed bars, each bar having a series of suitably spaced lugs t projecting laterally from one side thereof, to

provide vertically extendin air passages between the adjacent sides o the lugs at the side of the bar and between the ends of the lugs and the next adjacent bar, each of said lugs being extended above the level of the top of the bar and having fuel supporting faces on their upper ends and the sides of said lugs bein arranged to extend convergently downwar from the top of the bar.

6. A fuel grate comprising a series of spaced, horizontally disposed bars, each bar having aseries of lugsprojecting from each side thereof from top to bottom in opposite relation, the lugs of each bar being spaced uniformly from each other and from the adjacent lugs of the next adjacent bar, and being extended vertically above the level of the bars, to form projections, said nrojections having fuel-supporting faces at tieir upper ends disposed at an approximately uniform level, whereby vertically extending air pas-l sages are provided at the three sides of each lug and its projection and a horizontally extending passage is provided between the opposite projections of each lug, which open to said air assages at each end.

7 A ucl grate comprising) a series of spaced, horizontally disposed ars, each bar having a series of lugs projectinf1r horizontally from each side thereof, said lugs being spaced apart and terminating at a distance from the adjacent bars to provide air passages at each side and the ends thereof, and a projection extending vertically from the upper side of each lug with its sides extend ing continuously therewith at three sides and with its fourth side extending from the u per surface of the bar adjacent the line o its edge, and said projections having fuel-supporting faces at their upper ends.

8. A fuel grate comprising a series' of spaced, horizontally disposed bars, each bar having a series of lugs projecting horizontally from each side and verticaly from bottom to top thereof in opposite relation, said lugs being spaced from each otherl and from the lugs 'of the adjacent bars at v their ends and each lug having a projection extendin verticallyfrom the upper portion thereo above the level of the upper' surfaces of the bars, each projection havlng a fuel-supporting face at its upper end.

9. A fuel `grate comprising a series -of parallel, horizontally disposed and uniformly s aced bars, each bar having a series of uni ormly spaced lugs projecting horizontally from each side thereof, each opposite pair of lugs being in alignment with each other and with a corresponding pair of lugs of the other bars and the adjacent lugs of the next adjacent bars being spaced apart at their ends, eachlug1 having a projection formed continuously t erewitli and extending verticallyfrom the upper portion thereof, above the level of the 4upper surfaces of the bars, 13o

the opposite projections of each bar being spaced apart by approximately the width of the bar and said projections having fuelsupportin faces at their upper ends.

10. A uel grate comprising a frame having a series of regularly spaced, inwardly projecting lugs extending about the inner edge thereof, said lugs havin upwardly extendingI projections having uel-su porting faces at their upper ends disposed a ove the level of the grate, a plate mounted within the frame and comprising longitudinal and transverse bars having similarly spaced lugs projecting from each side thereof and proj ections extending vertically from said lugs 'above the level of said bars and havihg fuelsupporting faces at their upper ends.

11. A fuel gratebar having a horizontally disposed top surface and a series of suitably spaced lugs projecting laterally from one side of the bar and extending downward from said surface, roviding a vertically extending air passa e etween adjacent lugs, each of said lugs aving a projection thereon which extends continuously therewith above the level of said to surface and is provided with a fuel-supporting face on its top.

12. A fuel grate bar having a horizontally disposed top surface and a series of suitably spaced lugs projecting laterally from both sides thereof and extending downwardly from said surface, providing vertically lextending air assages between adjacent lugs, each of said ugs having a projection thereon which extends continuously therewith above thelevel of said top surface and has a fuelsupporting face on its top, and all of said projections being s a'ced apart to permit the passage of air entirely about the same.

13. A fuel grate bai` having a horizontally disposed top surface and a series of suitabl spaced lugs projecting laterally from bot sides thereof and extending downwardly from said surface, providing vertically extending air passages between adjacent lugs, each of said lugs having a projection thereon which extends continuously therewith above the level of said top surface, all of said projections being spaced apart to permit the assage of air entirely about the same and aving fuel-supporting faces at their tops disposed at approximately the same level.

titi

14.-. A fuel grate bar having a horizontally disposed top surface, a series of integrall formed lugs projecting laterally from eac side thereof in spaced relation and extending downwardly from i top surface and upwardly from said sur ace .to form projections having fuel-sup orting faces at theirtops, each proection eing formed to taper from said sur ace to its to and having its sides continuous with the sides of its corresponding lug..

15. A fuel grate bar having a horizontally disposed top surface, a series of integrally formed lugs projecting laterally in spaced relation from one side of the bar and extending downwardly from its top surface and having integrally formed projections extending upwardly from said surface, said roj ections having. fuel-supporting faces at t eir top ends and said lugs being formed to taper downward and said projections to taper upwardly from said surface, prqviding air passages between adjacent lugs, the sides of which converge to the top of the bar and diverge above the bar. f

16. A fuel grate bar having a horizontally disposed top surface and a series of lugs projecti-ng laterally therefrom in spaced relation, and formed integrally therewith, each lug being extended downwardl from a level adjacent said surface and aving an integral projection extending upwardly from said level and provided with a fuel-supporting face at its top, the corresponding sides'of each lug and its projection being continuously formed and the opposite sides thereof bein tapered oppositely from said-level to its en to provide vertically extending air passages between adjacent lugs and projections the sides of which converge toV said level and diverge from said level as they extend upwardly.

17. A fuel grate comprising a series of horizontally disposed bars arranged in parallelism'each bar having a series of integrally formed lugs pro'ecting laterally from each side in s aced relation and extending downwardly rom its top surface and upwardly frolnl said surface to form projections having fuel-supporting faces at their tops, the sides of each lug and its projection being oppositely tapered from said surface, and said bars being arranged to provide air passages between the outer sides of the lugs on each bar and the lugs on the next adjacent bars.

l18. A. fuel grate bar which comprises a longitudinal member, cross bars extending from said member, a lurality of spaced lugs projecting laterally rom both sides of said cross bars and extending downwardly from the top thereof to provide vertical air assages between adjacent lugs, and projections extending upwardly from said lugs and having flat to s lying above the top of said cross bars, the at tops of said projections forming a fuel 'supporting surface, said projections being spaced apart to permit air from said passages to flow between said 'projections to the fuel supported thereon.

19. In a fuel grate bar, the combination of a longitudinal member, cross bars extending from said member, a lurality of s aced lugs projecting laterally rom both si es of said cross bars, adjacent lu s in .part defining vertical air assages, an projections extending upward y from said lugs, each projection terminating in a flat fuel supporting surface of less area than the average cross-sectional area of the projection, said surfaces lying above the top of said cross bars and said projections bein spaced to permit air from said passages to ow between said projections to the fuel supported thereon.

In testimony whereof, I have signed my name to this specification.

' J OHN- J. BUCKLEY.

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