US2048383A - Furnace grate - Google Patents

Description

H. B. HOLT FURNACE GRATE July 21, 1936.

Filed Oct 23, 1934 2 Sheets-Sheet 1 vw aw Fwy/A 4:). AM @m lmm N WITNEzEEs Q H. B. HOLT FURNACE GRATE July 21, 1936.

Filed Oct. 23, 19-34 2 Sheets-Sheet 2 INVENTOR MW; m Mya- MTNESSES a 4. MW

Patented July 21, 1936 ear oFFIeej FURNAGEJ Gem 3 Harriet: H'olt, l'ibr'mbnti Pa; 7' Application flctober 2s, melee-term.masssv iziola ms; (o1 :11 o;4m V

This: inventiont relates e'tofurnace grates; and more. particularly to; traveling; grates of. the end.- lesswchain or beltitypfewhich; by their movements; carry: into furnaces new supplies ofi fueltor other 5 material. to be burned, andrcarryiiawawthe ashes remainingafter combustion's. i

Asv chain grates: become heated their' lateral expansion is: relatively -greatibecause ofthe large Widthr of such grates: There-fre,;the; grate or 19 fUIHBCQUI both, must be so-constructedas-to provide for thisexpansion' without-tleavi-ng-"opene ings through 1 the 1 grate. or: betweenithegrate;- andthe'furnace Wall through whichfuel: can escape when the grate is not'fullwexpandedi Various meansihave been suggested forsthispurpose, but they have generally been unsatisfactory; or'ex: pensive and difficult to construct and to reach forrepairs. i 7

It is among the objects-of this inventionato: provide a-grate the width of which=rernainssubstantially constant whether. the grate is hot or cold, and through which-fuel can not -fallq A151 other object is to-provide an expansib grate; in which the grate bars remain uniformly. spaced;- apart laterally under allltemperature.conditions.

Further objects are to providesuch agratewhicli is. relatively. simple and inexpensive to. construct: strong; dependable, very. unlikelyto get; out of order, and has means for maintaining" brazen 3Ov grate bars in "place. I I

In accordance 'withthis invention thereis pro: vided a grate including a support ifiith "a" "131' I; rality of grate bar supports extending transverse ly thereof. A plurality ofgratabars i's"mounted. sideby. side in rows on" the grate bar'supports; and means is connected to alternate bars in eacli row for spacingthe intermediatebarsuniform distances therefrom; Theinterrnediate bar'sarei loosely mounted ontheg-ratebansupportfs: 40 the spacing means and the portionsaof the i termediate bars which-engage-the spacing"me'a'nsare formed for elevating the intermediate-bars when i the bars expandtowardone "anethry When the bars contract; th'eelevated bars are' permittedto drop back to their original posi f tions andfthe spacing means agai-nmaintai-fi all oftthe bars equal distances-*apartL The bars a'r'e also provided .with means for interlocking them in; such manner that broken bars? are maintained in place until removed; v v

1 The'preferred embodiment of the invention 'is illustrated in the accompanying? drawings inc which Fig.1 ,is-a fragmentarvplanzviewlofinaria unexpandedendless chain @grate showm partly iin 55:;section and with some of the grate bars:remcued':-\;

pins 'l giiboth strands -of each=chaiinbeingn1cori Figs. 2 and.3 are viewsitalien on their-regular Iines II'-II and-IIIIIL respectivelyof- Fig-2 1; Fig; s a plamvievfi of one type of grate bar usediw-i-tli thegrate'; Fig; 5' isa side view thereof; Fig-6 is a -plan view of a second type of grate 1581 Used: With-*the grate; Fig. 7 is'a'lside new tliereof'eFiglt is a rear VieW,- partly ini's'e'c'tion; of threegrat'e bars in the positions they occupy whert'thegrate'iscold; and-Fig.- 9 is a"viw, -siif1-' ilar to Fig; 8;: showing. the grate bars in the p05 sition s they -occupywhen they: have expanses;

Referring: to the'drawin'gs, a traveling chain V grate isishown as being formed-of wa general parts=,l'-amend1esslchain or belt I" and fuel-sup portinggrate bars mounted thereon. The pre ferred' construction 'of this belt is best illustrated in Figl lwhere the belt is shoWri-ascofnprising a; plurality of parallelichain's*3 retainedin spaced relation by means ofcylindrical spacing menubersfll rand -grate bar supports 5. The chains are preferablya -of the double strandtype' adapted to tiravelmover: sprockets- (not? shown) at the: ends ofua l furnace and formed from' a plurality of links fi pivotallyiconnected at their ends by pivot nected by the same pins to bring their c'orre-'- spending piv'ot axes into alignment; A"plurality ohthe spacing .members 4* and grate 'bar sup ports 5 ."servex-to retain the chains and" their strands of links in: predetermined -spaced parallelrelatiom; thereby" completing: the 'belt;

5' The cylindrical spacing members d aredisposed between the strands of each chain with the "pivot pins J= extending; .therethroughp and the" grate bartsupports"5.;have -tubularend portions: l l into which the rendsr of pivot 1 pins in adjacentchain's projectw One sideof: the body! portion between the {tubular ends-of:- eachgrate bai support is open, 131$ at I 2;- :t'o give access to the pivot'pins projecting into itso-that they maybe readily drivewout-or 1 replaced should the belt" require repairingaand also to eliminate unnecessary weighti-R- i i As shown' 'in Fig. 2, each of: the grate barsup ports =is-;provided with an integral radia'l ribi I 3* projectin gs outwardly from the belt and havir'ig oppositely disposed side flanges l4 extending-w therefromie The? rib and flanges project-w across" the pivoted-ends of the adjoiningelinks to within arshortadistance 'of the other 'grate bar supports in 1 line therewith and thereby form transverse" parallelrowsowithi each row taking-' the form of a--rsub'stantial ly continuous grate bar" supportw The-'tubularend portions" I I ofthe grateubar' s'up portsaare:proividedtwith radial bores "l fi regi's'tr by the arrows in Figs. 1 and 2. The front end,

of each link 6 is provided with a pair of upwardly tapered lugs 2| forming between them a V-Shaped recess 22, as shown in Fig. 2. The portions of the grate bar supports which project across the links are formed for engaging the lugs in recesses 22, whereby the grate bar supports are rigidly positioned with relation to the row of links whose lugs 2| they engage. A plurality of fuel-supporting grate bars 2a and 2b is slidably mounted on each row of grate bar supports, the lower portion of each bar being provided with a recess 23 (Figs. 2 and 5) for receiving radial'rib l3 and its flanges I4, and with inwardly projecting lugs 24 for engaging the under surface of the flanges to retain the grate bar on its support. The grate bars are prevented from sliding ofi the ends of their supports by end bars 26 (Figs. 2 and 3) that are slidably mounted on the grate bar supports in the same manner as the other bars. Bars 26 are held in place by plates 21 which engage their outer sides and are detachably connected to belt I by means of nuts 28 threaded on pins 29 whose'inner endsare threaded in openings in the ends of adjoining pivot, pins and in ribs l3 of adjoining grate bar supports, the outer ends of pins 29 projecting through plates 21. The fuel-engaging surfaces of the outermost grate bars 26 are wider than the fuel-engaging surfaces of the other bars, and the bars 26 project laterally from the belt be-' yond the grate elements below them and travel in' close proximity 'to the furnace walls, not shown. a r v The outer surface of each grate bar is preferably of the form shown in Fig. 2 with the outer surface of its nose 3| formed as an arcuate por-,

tion of an imaginary cylindrical surface coaxial with the pivotpins supporting the grate bar sup-' port oriwhich the'bar is mounted, so that when thegrate rounds the curved endsof its path in a" furnace therows of grate bars do not spread apart and open up the fuel-supporting surface. The noses of the grate bars are also preferably narrowed in width to form ash-receiving recesses 32 between them for receiving'ash at one end of the grate and discharging it at the opposite end.

It is a feature of this invention that the grate is so'constructed that its parts can fully expand and contract with temperature changes without changing in overall width to any appreciable extent and' without'forming openings through its fuel-supportingsurface through which fuel can fall; Accordingly, the diameters of the bores l6 and I1: through .the grate bar supports and the pivot pins are somewhat greater than the diameter of the bolts disposed therein, and the length of the supportsis less than the distance between the sprocket-positioned chains 3 when the grate isxcold. Consequently, when the grate becomes heated and the members constituting the beltexpand. transversely thereof, the grate bar supports and the pivot pins are'permitted to telescope relative to each other, whereby, although the constit-- uen't members of the belt expand, the overall width of the belt is not noticeably increased.

As the grate bars also expand with the heat, it is necessary to make provision for such expansion. A former way of doing this was to put a fewer number of bars in each row than the row would accommodate and to then spread out the bars to provide substantially uniform spaces between them into which they could expand. However, it is obvious that as there was nothing to maintain this uniform spacing of grate bars the vibration of the moving grate caused them to work together in groups or towards one side of the grate, thereby leaving relatively large open spaces in the fuel-supporting surface of the grate through which fuel could fall.

Applicant has eliminated this difficulty by providing some of the grate bars in each row, preferably alternate bars 2a, with laterally projecting lugs 33 (Figs. 4, 5 and 8) which engage the sides of adjoining or intermediate grate bars 2b and space them therefrom, all of such spacing being uniform. Either the surfaces 34 of intermediate bars 2b that engage lugs 33 or the lugs upper surfaces which engage the intermediate bars, preferably both as shown in Figs. 8 and 9, are inclined upwardly toward the adjoining bars 2a. The grate bars are slidably mounted on their supports, and recesses 23 are large enough to provide sufiicient play between the bars and sup ports to permit bars 2b to move outwardly relative to the supports within predetermined limits,

When the bars in any given row'become heated and expand laterally there is a tendency for the inclined surfaces 34 of intermediate bars 2b and the inclined upper surfaces of lugs 33 to move toward each other in a plane parallel to belt I, but movement in such a plane is impossible be-- cause these surfaces are already in engagementwith each other. Consequently, intermediate bars; 2b ride up the inclined surfaces of lugs, 33; as the bars approach one another, the loose play be. tween bars 2b and their supports permitting their elevation in this manner. Thus, although the grate bars are originally spaced apart by positive means (lugs 33), such means do not prevent the spaces between the bars from being closed up when the bars expand, as shown in Fig. 9, whereby lateral expansion of the grate bars is permitted without increase in the length of the rows of bars.

When the grate cools, the surfaces of the grate bars in effect move away from each other and, as any given alternate bars 2a contract, the inover against an adjacent bar 2a and thereby leave a space between itself and the bar adjacent its posite side which is double the width it would be if the intermediate bar were equally spaced from adjacent bars 2a on both sides of it, because the force of gravity causes it to slide down lugs 33 to a point midway between the adjacent bars 2a.

End bars 26 are neither provided with elevating lugs nor elevated when the remaining grate bars expand, but the end portionsof grate bar supports 5 on which the 'end bars are mounted are recessed slightly to form shoulders 35, 'as shown in Fig. 3, for limiting the distance that the end bars can move inwardly away from the sides of the grate.

. supports 15. and tiltingup at theirrear ends, the

rear portions of, those bars are provided with lateral-ly projecting lugs 36 adapted to strike against the lower faces of shoulders 3.1 on bars 2a when bars 2b attempt to tilt or are elevated, by expane sion. .Lugs 36 are disposed farther down from the fuel-supporting surface of a. grate bar than are lugs 3.3 so that they will not interfere with the desired elevation of bars 219;. Rear lugs 33 on grate each grate bar is provided with a, laterally projecting lug 38'and the'opposite side is provided with a lug-receiving socket 39, these lugs and sockets registering throughout the length of each row. Thus, the front portion of a broken grate bar is supported by the lug 38 which projects into the socket 39 of the broken bar. As soon as a broken grate bar is discovered it can be removed by sliding the bars off one end of their support and sliding on a new bar. Sockets 39 are of such depth and breadth relative to the length and breadth of lugs 38 as not to interfere with the expansion of the grate bars and the raising of bars 2b.

A furnace grate constructed in accordance with this invention can be placed in any furnace without having to construct the furnace to allow for expansion of the grate. The grate takes care of its own expansion so that it does not increase in width a noticeable amount. The grate bars forming the surface of such an expansible grate remain uniformly spaced apart laterally so. that openingsare not formed in the fuel-supporting surface through which fuel could fall and jam the grate or be wasted. The expansion compensating means are simple and'inexpensive and practically certain not to get out of order. Furthermore, in case a grate bar breaks in this grate the broken pieces are held in place until discovered and removed. v

According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention, and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A grate comprising a support, a plurality of grate bar supports connected thereto, and a plurality of grate bars mounted side by side in a row on each grate bar support, alternate bars in each row being provided with means engaging and spacing the intermediate bars therefrom, the intermediate bars being loosely mounted for free vertical movement on each grate bar support, and said means and the portions of said intermediate bars engaging said means being formed for elevating the intermediate bars when the bars expand toward one another, whereby said spacing means do not interfere with lateral expansion of the grate bars.

2.. A, grate comprising a support, a plurality of grate bar, supports connected thereto, and a plurality of grate bars mounted side by side in a row on each grate bar support, alternate bars in each row being provided with means engaging and spacing the intermediate bars therefrom, the intermediate bars being loosely mounted for free vertical movement on each grate bar support, the engaging surfaces of said means and the. portions of said intermediate bars engaging said means being inclined for elevating the inter mediate bars. when the bars expand laterally toward one another.

3. A grate comprising a support, a plurality of. gratebar. supports connected thereto, and a plurality of grate bars mounted side by side in a row on each grate bar support, alternate bars in 'each row being provided with means engaging and spacing the intermediate bars therefrom, said intermediate barsbeing provided with shoulders projecting laterally therefrom, said bar-spacing means projecting below said shoulders on the sides of the intermediate bars, the latter being loosely mounted for free vertical movement on each grate bar support, and the shoulder-engaging surfaces of said means being inclined downwardly and outwardly, whereby the intermediate bars are elevated by said means when the grate bars expand laterally.

4. A grate comprising a support, a plurality of grate bar supports connected thereto, and 'a plurality of grate bars mounted side, by side in a row on each grate bar support, alternate bars in each row being provided with means engaging and spacingthe intermediate bars therefrom, said intermediate bars being provided with shoulders projecting laterally therefrom, said bar-spacing means projecting below said shoulders on the sides of the intermediate bars, the latter being loosely mountedfor free vertical movement on of and supported thereby, a plurality of grate bars mounted side by side in rows on the grate bar supports, and lugs projecting laterally from the sides of alternate bars in each row and engaging the intermediate bars for spacing all of the bars substantially equal distances apart, the intermediate bars being loosely mounted on the grate bar supports for free vertical movement thereon, the lugs and the portions of said intermediate bars engaging the lugs being formed for elevating the intermediate bars when the bars expand laterally toward one another.

6. A grate comprising a support, a plurality of grate bar supports extending transversely thereof and supported thereby, a plurality of grate bars mounted side by side in rows on the grate bar supports, and lugs projecting laterally from the sides of alternate bars in each row and engaging the intermediatebars for spacing all of the bars substantially equal distances apart, the intermediate bars being loosely mounted on the grate bar supports, the engaging surfaces of the lugs and the portions of the intermediate bars engaging the lugs being inclined for elevating the intermediate bars when the bars expand laterally toward one another.

7. A grate comprising a support, a plurality of grate bar supports extending transversely thereof and supported thereby, a plurality of grate gaging the intermediate bars for spacing all of the bars substantially equal distances apart, the intermediate bars being loosely mounted on the grate bar supports, the portions of the intermediate -bars engaging the lugs being formed as shoulders, the shoulder-engaging faces of the lugs being inclined downwardly and outwardly and the lug-engaging faces of the shoulders being inclined upwardly and outwardly, whereby the intermediate bars are elevated by the lugs when the bars expand laterally toward one another.

8. An endless traveling chain grate comprising a plurality of endless chains advancing in parallel paths and formed of links pivotally connected at their ends by pivot pins aligned in parallel rows, a plurality of grate bar supports provided at their ends with axial bores for slidably receiving the ends of said pivot pins whereby axial movements of the grate bar supports and the pivot pins relative to each other are permitted as the grate expands and contracts with temperature changes,

.means for limiting said axial movements, and a plurality of grate bars mounted side by side in rows on the grate bar supports, alternate bars in each row being provide-d with means engaging and spacing the intermediate bars therefrom, the intermediate bars being loosely mounted on the grate bar supports for free vertical movement thereon, and said means and the portions of said intermediate bars engaging said means being formed for elevating the intermediate bars when the. bars expand laterally toward one another.

- 9. A grate comprising a support, a plurality of grate bar supports extending transversely thereof andsupported thereby, and a plurality of grate bars mounted side by side in rows on the grate bar supports, alternate bars in each row being provided with means engaging and spacing the intermediate bars therefrom, the intermediate bars being loosely mounted on the grate bar supports 'for free vertical movement thereon, said means and the portions of said intermediate bars engaging said means being formedfor elevating the intermediate bars when the bars expand laterally toward one another, and means connected to the bars for limiting longitudinal rocking of the intermediate bars on said grate bar supports relative to said alternate bars.

' 10. A grate comprising a support, a plurality of a grate bar supports extending transversely thereof and supported thereby, a plurality of grate bars mounted side by side in rows on the grate bar supports, and lugs projecting laterally from the sides of alternate bars in each row and engaging the intermediate bars for spacing all of the bars substantially equal distances apart, the intermediate bars being loosely mounted on the grate bar supports, the lugs and the portions of said intermediate bars engaging the lugs being formed for elevating the intermediate bars when the bars expand laterally toward one another, said alternate bars being provided with side shoulders, and lugs on the sides of the intermediate bars projecting beneath said shoulders, whereby rocking of the intermediate bars on said grate bar supports relative to said alternate bars is materially limited.

11. A grateicomprising a support, a plurality of grate bar supports extending transversely thereof and supported thereby, a plurality of gratebars mounted on each grate bar support andincluding a plurality of grate bars loosely mounted for free vertical movement on said grate bar support, said loosely mounted bars being adapted to be elevated relative to the remaining bars on said grate bar support and all of said bars being disposed. side by side in rows, and lugs projecting laterally from the sides of the grate bars adjacent said loosely mounted bars for engaging and spacing the latter therefrom, the engaging surfaces of said lugs and the portions of said loosely mounted bars engaging the lugs being inclined for elevating said loosely mounted bars when the bars expand laterally toward one another.

l2.-A grate comprising a support, grate bar supports connected thereto, and a plurality of grate bars mounted on each grate bar support and including a plurality of grate bars loosely mounted for free vertical movement on said grate bar support, said loosely mounted bars being adapted to be elevated relative to the remaining bars on said grate bar support and all of said bars being disposed side by side in rows, the grate bars adjacent said loosely mounted bars being provided with means forengaging and spacing the latter bars therefrom, and said means and the portions of said loosely mounted bars engaging said means being formed for elevating the loosely mounted bars when the bars expand toward one another, whereby said spacing means do not interfere with lateral expansion of the grate bars.

HARRIS B. HOLT.

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