US1976746A - Furnace grate - Google Patents

Description

OCL 16, 1934 c. F. REGAN 1,976,746

l FURNACE GRATE Original Filed Oct. 23, 1929 2 Sheets-Sheet. l

@EVIL JZ /4 r//p /8 Y h 'l x11" IlIIA [NI/ENTOR ATTORNEY oct. 16, 1934. Q F REGAN 1,976,746

FRNACE GRATE Original Filed Oct. 23, 1929 2 Sheets-Sheet. 2

INVENTOR 4 Troie/VE y Patented Oct. 16, 1934 OFFICE FURNACE GRATE Charles F. Regan, New York, N. Y., assigner to Caroline Regan, New York, N. Y.

Application October 23, 1929, Serial No. 401,639 Renewed February 20, 1934 2G Claims.

My invention relates to improvements in furnaces and more particularly to furnace grates, and has for one of its objects to provide a furnace grate having a very low resistance to the passage g 5 of air therethrough, so that suiicient air finds access to the fuel on the grate to insure complete combustion of such fuel and is distributed uniformly over the surface of the grate. It is also an object of the invention so to construct a furnace l grate that the same may easily and quickly be repaired by the attendant or householder without the need of expert help or of special parts. It is a further object of the invention to provide a grate which is composed of easily removable and l replaceable parts of simple construction which can be manufactured at a low cost. Other objects Will appear from the description following and the features of novelty Will be pointed out in the claims.

One of the most important considerations in the design and construction of a furnace grate is the insurance of a suicient supply of fresh air for the fuel so as to obtain as complete and as uniform a combustion as possible. For eicient and economical combustion, not only must provision be made for an abundant supply of air during the comparatively slow burning of the free carbon content of the fuel, which is generally anthracite coal, but a sufficient quantity of air must be present to burn, at the surface of the fuel on the grate, the combustible vapors and gases which quickly escape when a new layer of coal is spread over the bed of incandescent coals on the grate. With known types of grates a large part of these combustible gases and vapors escapes from the combustion space and is lost before enough oxygen can reach the same to support combustion thereof. This has been due largely to the fact that grates as heretofore constructed have usually been composed of a more or less flat plate of metal provided with slots for the passage of air, the area of the metal surface being generally greater than that of the slots, so that great resistance is encountered by the air. These slots have to be .45 made small to prevent the fuel from falling through the grate; at the same time, since the grate element is produced by casting, it is necessary to make the metal strips dening the slots rather wide, for if the metal lacework were made `5i) thin and delicate, the pattern could not be removed from the sand in the mold without injuring the impression, while the molten metal on pouring would frequently solidify before'filling all the fine passageways and on cooling strains would be 2 set up because of the difference in the rate of cooling between the heavy mass of metal at the ends of the grate element and the thin lacework of metal intermediate such ends, so that defective castings would frequently result. For these reasons, known grates of this type are made with comparatively large and continuous metallic surfaces between the air slots so that, as stated, great resistance is opposed to the flow of air and combustion is consequently incomplete. Other Vgrates are known which are composed of a number of separate elements designed to'be arranged side by side upon a grate bar and locked thereto, and provided with spaced teeth between which flowed the air for supporting the combustion. The present invention relates to this latterftype of grates. As heretofore constructed, the teeth, spacing members, supporting grate bar, and other members forming part of or associated with the grate offered considerable resistance to the flow of air and prevented complete and uniform combustion. In my copending application Serial No. 347,367, filed March 15, 1929, of which the present application is a continuation in part, I describe a novel form and arrangement of teeth for the grate elements whereby the resistance to the ilow of air is reduced. In the present application I shall describe, among other things, a novel form of grate element, grate banand grate frame whereby not only is the flow area for air still further increased and the air-resistance correspondingly diminished, but the replacement of parts is facilitated and the cost of manufacture reduced, while at the same time the shaker mechanism for rocking or dumping the grates is simplified and rendered flexible in a manner to be explained hereinafter.

My invention will best be understood by reference to the accompanying drawings which show by way of example a preferred form of the invention. In said drawings,

Fig. l is a plan view of a grate constructed in accordance with the present invention, and shows the grate bars in position on the grate frame and a number of the grate elements in position on the bars;

Fig. 2 isa side View of a completely assembled grate and illustrates the shaker mechanism therefor;

Fig. 3 is a front view of the mechanism shown in Fig. 2;

Fig. 4 shows an enlarged perspective of a grate bar; v

Fig. 5 is a section along the line 5 5 of Fig. 6; Fig. 6 illustrates an enlarged front view, partly 110 in section, of a grate bar with a number of the grate elements thereon; and

Figs. 7 and 8 illustrate two forms of grate elements forming part of a grate bar assembly.

My improved grate comprises a frame 10 having aligned pairs of sockets 11 designed to receive the trunnions 12 on grate bars 13 a1l as clearly shown .in Fig. 1. Thefrarne 10 is composed of two side members 14 connected at their V'ends by bars 15, the side members and end bars being connected in any suitable manner, as by means of atapered tongue and groove connection 16. Upon each of the grate bars are mounted a plurality of grate elements 17, to be described more in detail hereinafter, only a small number of such elements being shown in position in Fig. 1. "It will be understood that `a number Iof assembled frames 10 may be arranged side by side within the combustion space of a furnace, the frames being mounted in any desired fashion upon a suitable` foundation. r

In yaccordance with -the present invention th .grate bars 13 areconstructed in .such a manner that they offer-a minimum of resistance to ow Iof air-upwardly through the grate andalso provide -for .suflicient clearance between `adjacent lgrate elements Y.and .grate bars when the latter are-oscillatedxor .rocked to dumpthe Igrate Aelements. As shown more in Adetail in-Fijg. 4, the Vbar.1f3 is composed of Ia pair of spaced longitudinal side members .connected at their ends by the plates .18, .such lplates Ycarrying the trimnions .1-2.

The -side members are connectedonly at their-ends so vthatuthe interior -of the bar is free of any obstruction for a purpose .to be set .forth hereinafter. 4It `will be observed that the bar 13 isofextremely simple form, presents only ya small mass `of metal -in the path of flow of the air, and can .be easily manufactured .at a low cost. The side members are preferably `parallel to each other, as shown, but they may, `if desired, be inclined yto the vertical. The edges of the side members may be slightly beveled, as .shown at 18 to reduce deformation as a result of expanysionand contraction.

.'-Ihe bars 13 are each designed to support a plurality of removable grate elements 17 larrangedin'separate rows thereon. As shown in Fig.-.8,-'each fof the elements 17 comprises a segment-like por-tion19 from which extends centrally thereofa stern of tongue portion 20.V This tongue lportionis preferably vso dimensioned that it ts closely or snugly between theside members o'f thebar 1.3. In this manner the .bar 13 vis reinforced bythe tongues ofthe jgrate elements 1'7 against distortion, and especially against inward bending of the side members of the bar. The grate velements are each provided with slots 21 adapted .to receive the upper ends of the side members of 'the grate bar as the elements are lowered onto the bar, the walls o'f such slots cooperating with the bar to prevent more than slight transverse movement ofthe'grate elements with'respect to the bar. As will be 'clear from 1. Figsul, '5, 6 landv', thegrate elements may easily be inserted upon or removed from the grate bar merely by'lowering or raising the same vertically and without `disturbing any of the other `grate elements on such bar. A defective or burnt-out element 'can .therefore be removed and replaced with very little effort and in a very short time. Itwill also befclear ,that thegrate-elements can readily be slid along the length of the bar as no obstruction isvpresent toprevent such movement. -While each grate element isshownas provided with two slots, a single slot may in certain cases be suflicient.

The upper edge of the grate elements, as shown in Fig. 8, is preferably made highly convex longitudinally of such elements, i. e. transversely of the grate bar, thereby increasing quite considerably the eifective area of the grat-e. The upper edge of the grateelements is alsorounded transversely of such elements as shown in Figs. 3 and 6 and as 'described in my above-mentioned application.

Mounted upon each side of the grate elements and below the top edge thereof is an arcuate row of opposing walls of adjacent teeth thus diverge at the upper portionscf the teeth, thereby promotingV distribution of air longitudinallyof the grate elements, such "air rising from below the teeth. The grate 'elements are adapted to be so positioned upon the grate bar that opposed sets of teeth `upon adjacent elements are 4preferably in alignment and spaced from each other. .'Ihis spacing is accomplished by -means lof lugs 23 integral with the .grate elements and, like the teeth 22, Vbuilt in the form `of 'truncatedrcones The lugs on each side of an element are spaced from each other; the lugs are also rsmall in sizefso that they offer vvery little resistance to the air.

As'shown in Figs. 1, 3 and 6, the si'de members 14rof .the .frame 10 :are curved so as to correspond with the outline of therows of grateelcments arranged between the same. The body of .fuel may consequently extend to and upon the side .members fso that vthe effective grate area .is increased. .In order to improve the circulation of air at such side members, I provide the latter1 with teeth which are similar to the teeth on the :grate elements, 'and in order to `bring the opposing Vseries of teeth of the last or end grate elements onthe grate bars close to the teeth on .the grate 'frameglcmit the spacing lugs..23 Afrom Vthe outeriface lof such end grate elements (see Fig. 6) .Toinsure 'a :suflicient draft of .air from the isides of vthe frame I 'provide the side inemhers with'air vents 24 adjacent to the upper 'surface thereof. The end bars 15 are similarly provided with air `vents 25.as illustrated in Fig. 3.

.As shown in Figs. 2, 3, 5, 6, and 7, at least one ofthe grate `elements on each ofthe bars 13 is .provided withan extension 26 having an opening .27 `through which it'may be bolted to a shaker bar 28 operated in lany suitable manner from the front of the furnace. This element is preferably 'the lend element as'shown in Fig. 6 and is in other .respects similar to the elements 17. When it :forms one of the Vend elements on a grate bar,'it is provided with spacing lugs 23 at 'only Athe rone side thereof. In order to prevent suchend element 17 from working its way up through the :bar 13 as the same is oscillated, the extension 26 is enlarged at its upper end to provide shoulders 28 which engage the underside of the bar I.13. To facilitate insertion of the enlarged extension`26 through the bar 13, the latter is'provi'ded at its underside with slots 29 which are out of alignment with each other, as shown in Figs. 4 and 6. To positionY the end element 17 upon the bar'13 the former is'inserted between the side members ofthe latter in an askew manner as indicated in dotted'lines in Fig. 1, so that the shoulders 28 engage the slots 29, whereupon the element may be turned until it is at right angles to the bar and may thenbe slid to the end of the latter.

- It will be seen that by the provision of an eX- tension on one of the removable grate elements I dispense with the necessity of casting a shaker arm vintegral with the grate bar 13. In 'this way I not only simplify the construction of the grate bar, but facilitate and reduce the cost of replacementshould the shaker bar become damaged or broken; for should such arm be broken in known constructions, wherein it forms an integral part of the grate bar,not only must the whole grate bar be replaced, but the whole assembly must be removed from the grate frame. In Yan apparatus constructed in accordance with the present invention it is only necessary to remove and replace the end grate element 17 without in any way disturbing the grate bar or more than one or two of the grate elements 17. Such replacement can easilyV be done by a non-skilled attendant or householder in a very short time.

A' further advantage of that feature of my invention which involves the attaching of the shaker arm to one of the grate elements resides in. the fact that Where insuicient clearance eX- ists at the end of the grate bar for the shaker mechanism, `as for example, in circular furnaces, the special grate element 17 provided with the eX- tension A26 may be moved inwardly upon the grate bar until sumcient clearance is provided, the space on the bar between such element and the endof the bar being filled with the normal elements 17.

It will be clear from Figs. 4, 6, 7, and 8, that the grate bar and elements constructed in accordance with my invention present a minimum of obstruction to the flow of 'air through the grate, so much so that complete land uniform com-bustion can be obtained with a natural draft, the gases and vapo-rs escaping from a new charge of coal being completely burned at the surface of the grate. The grate elements, it will be noted, are composed for the greater part of a nat, comparatively thin, strip or web of metal while the spacer lugs 23, of which preferably three are provided on each side of the elements, except, of course, the end elements, are small and do not im/pede the now of. air. As a result a large volume of air reaches the |teeth 22 which are spaced both from each other and from the opposing set 'of teeth, so' that the air encounters little resistance and gains ready access to the fuel on the grate. The construction of vthe parts is such that the air spreads in a fan-wise manner through the teeth 22 transverse-l57 of the grate bar because of the fact that they encounter no angular or sharp corners, such spreading being promoted by the -flaring path afforded each stream of air passing between adjacent teeth, as will be clear from Figs. 5, 'Tand 8. Furthermore, because ofv the fact that the teeth taper outwardly while V the l'grate teeth. Ast'he teeth are dropped below the upper edges of the grate elements, considerable space is provided between the bed of -coal on the grate and the teeth, the air circulating through such spaces. In this manner Ithe air encounters aminirnum lof resistance and is distributed uniformly over the surface Iof the grate. The grate elements may be provided with vents 29 through'which the air may course to cool the elements where they are hottest.

My ini-proved grate can be easily installed in any type of furnace in a very short time and requires no bricking up or special foundation. The parts described above can be manufactured in any foundry and require no special apparatus.

In order to prevent binding of the grate bars against the sides of the frame as a result of eX- pansion, I provide washers 12 at the endsof the bars, which are arranged to engage similar projecting washers upon the frame.

Variations may be resorted to within the scope of the appended claims without depanting from the spirit of the invention.

I claim:

1. In a furnace grate, in combination, a grate bar of substantially rectangular cross-section and including two spaced substantially vertical side member-s, and a plurality of substantially T-shaped grate elements whose stem portions are 'adapted to t snugly between said side members, whereby the latter are reinforced by said stem portions against distortion inwardly, the horizontal portion of said T-shaped elements being pcvided with rectangular notches arranged to receive snugly the upper edges of the said side members as said elements are lowered onto the grato bar, whereby said side members are reinforced against distortion. cutwardly -by the outer walls of such notches, said grate elements resting only upon the upper surfaces of said side members and each being removable and replaceable by free vertical movement thereof with respect 'to the grate bar without disturbing the remaining elements.

2. The combination as set forth in claim l including an additional T-shaped grate element having `an extension on its stem for connection with anr actuating member for rocking the grate bar.

3. In a furnace grate, in combination, a grate bar of substantially rectangular cross-section and-including two spaced substantially vertical side members, a plurality of substantially shaped grate elements whose stem portions are adapted to iit snugly between said side 'members, whereby the latter are reinforced by `said stem portions against distortion inwardly, the honizontal portion of said T-shaped elements being provided with rectangular notches arranged to receive snugly the upper edges of the said side members as said elements are lowered onto the grate bar, whereby said side members are reinforced against distortion outwardly by the outer walls of such notches, said grate elements resting only upon the upper surfaces of said side members and each being removable and replaceable by free vertical movement thereof with respect to the grate bar without disturbing the remaining elements, and spaced coneshaped spacing lugs on each of said grate elements adapted to engage similar lugs on an adjacentelement for holding such lelements in soaced relation to aiford a substantially unobstructed passage for air lbetween said elements.

e. In a furnace grate, in combination, a grate bar comprising a pair of spaced side members, and a plurality ofsubstantially T-shaped lgrate elements whose stems fit snugly between said side members and operate to reinforce the latter against distortion inwardly, said elements resting upon the upper surfaces of said side members and each being individually removable from the bar by lifting thesame without disturbing the other elements, and a row of spaced, conical, fuelsupporting teeth at each side of each of said elements vertically spaced from the uppermost edge thereof.

- 5. In combination, a grate bar comprising a pair of spaced side members, andagrate element having an intermediate portion of such width as to fit snugly between the said members and having an enlarged bottom portion adapted to be connected to a shaker bar, said members being provided with notches at their lower edges, said notches being out of alinement, whereby said element may beinserted obliquely between the side members of the bar and then be turned so as to cause the enlarged portion thereof tez-enter said notches to permit the said element 'to be positioned at right angles to such bar.

6. In a furnace grate, in combination, a grate bar` comprising a pair of spaced side members of rectangular cross-section, aplurality o-f grate elements resting on said bar, and each being individually .removable from the bar by lifting the element, While the other elementsare in position on. the bar, without -disturbing .such other elements, and spaced teeth in the vicinity of the upper edge of each clement, each element being provided with rectangular slots arranged to receive snugly the said side members, whereby said barfis-reinforced against outward distortion by the outer walls of such notchesfv Y 7.-'Ihe combination as set forth in claim wherein said grate bar is free of transverse webs intermediate its ends, whereby the grate elements resting onthe bar can be'shifted therealong.

8. In a furnace grate, in combination, a grate bar comprising a pair of Vspaced side members, a plurality of grate elements vresting on said bar and capable of movement longitudinally of said bar while in position thereon, each of said elements being 4individually removable ffrom and replaceable on such bar while the remaining elements are in place without disturbing suchv remaining elements, spaced teeth in the vicinity of the upper edge of each element, and means for rocking said bar parallel to the planes ,of said elements, said teeth being in the form of a truncated cone.

A9. In a furnace grate, in combination, a grate bar consisting of only two spaced verticalside members which are smooth upon ltheir inner faces, the bar being free of transverse webs intern mediate its ends,rand a pl-urality of substantially T-shaped grate elements whose, stem portions have parallel vertical edges and are of such width as to fit snugly between the vertical side members of the grate bar, grate teeth on said elements, and spacing lugs on said elements, said elements being placeable on and removable from said side members merely by free rvertical movement, and said teethbeing of curved outline in planes parallel to the said elements and beingdisposed below the top edgesof said elements, wherebyresistance to the. passage of air is reducedand spreading of such air longitudinally of said elements -is promoted. f

10. In a furnaceV grate, in combination,l agrate bar comprisingv a pair of spaced. side members, and a plurality of substantially T-shaped grate elements whose stems nt snugly between said side membersv and operate to reinforce the latter against distortion inwardly,- said elements resting upon the upper surfaces of said side members and each being individually removable from-.the bar bylifting the same while the 'other elements are in rposition .on the bar, without disturbing such other elements, each of said elements having on each side thereof a row of spaced, fuel-supporting teeth which are 'curved at the upper portionsv thereof and are arranged below the uppermost edges of said elements a suicient distance to enable air travelling upwardly between the elements and between the teeth to ow over the curved surfaces of suchteeth through-the space between such teeth and the top edges of the elements and become distributed along the length of such elements below the bed of fuel resting on the latter. f

11. In a furnace grate, in combination, a grate bar of substantially rectangular cross-section and including two'spaced substantially vertical side members, and .a .plurality of substantially T- shaped grate elements whose stem portions are adapted to fit between said side members, whereby the latter are reinforced by said stem portions against-distortion inwardly, the horizontal portion of said T-shaped elements being provided with rectangular notches, which receive said members, the outer walls of said notches snugly vengaging said members so that such horizontal portions reinforce the members against distortion outwardly, spaced teeth on said grate elements, said `spaced' side. members and spaced teeth affording a passageway of l-arge area for air pass-- ing upwardly between the grate elements, said elements having each an aperture therein near the top thereof to permit the air to travel transversely of the elements to cool the latter.

12. In-a furnace grate, in combination, a rack member, a plurality of grate units mounted on said member, and grate teeth on each of said units, at least the upperportions of said teeth being of curved outline, longitudinally of such units, whereby corners are eliminated at the upper portions of said teeth and the opposing walls of adjacent teeth diverge at the top portions of said teeth so that air flowing upwardly between the teeth spreads over the length of said units, the upper surfaces of said elements being convexly curved in planes transverse to the length ofthe rack member.

13,"In a furnace grate, in combination, a grate bar, a plurality of grate elements removably mounted on said bar, and grate teeth on said elementsbelow the top surface of said elements, said teeth being of the form of a truncated cone, whereby corners are eliminated and resistance to the passage of air reduced.

i4.v In a furnace grate, in combination, a grate bar, a plurality of grate elements removably mounted on said bar, and grate teeth on said elements below theV top surface of said elements, the top surface of said elements being curved transversely thereof and said teeth being of curved outline,` whereby corners are eliminated and resistance to the passage of air reduced.

, 15. -In a furnace grate, in combination, a grate bar, a. plurality of grate elements removably mounted on saidl bar, and grate teeth on said elements belowthe-top surface of said elements, the top surface of said elements being curved transversely thereof and saidteeth being of the form of a truncated-cone, whereby corners are eliminated and resistance tov the passage of air reduced.

16.` In a furnace grate, in'combination, a grate b ar, a plurality of grate elements removably mounted on said bar, and grate teeth on said elements .below'the top surface of said elements,

the top surface of said `elements being curved transversely and longitudinally thereof and said teeth being of the form of a truncated cone, whereby corners are eliminated and resistance to the passage of air reduced.

17. A removable grate element comprising a web member, and a row of spaced teeth upon each side of said member, said teeth being tapered transversely of the web member and of substantially circular vertical cross-section, and said rows of teeth being spaced from the top edge of said member to such an extent as to induce currents of air passing upwardly between the teeth to spread longitudinally of said web member and over the top edge thereof.

18. In a furnace grate, in combination, a grate bar, and a plurality of grate elements remov ably mounted on said bar, certain of said elements comprising a web member and a row or" spaced teeth upon each side thereof, said teeth being tapered transversely of the web member and of substantially circular vertical cross-section, kand said rows of teeth being spaced from the top edge of said web member to such an extent as to induce currents of air passing upwardly between the teeth to spread transversely of said web member and over the top edge thereof.

19. In a furnace grate, in combination, a grate bar, a plurality of grate elements mounted on said bar, and grate teeth on each of said elements, at least the upper portions of said teeth being of curved outline longitudinally oi such elements, whereby corners are eliminated at the upper portions of said teeth and the opposing walls of adjacent teeth diverge at the top portions of said teeth so that air flowing upwardly between the teeth spreads over the length of said elements. c

20. In a furnace grate, in combination, a grate bar, a plurality of grate elements removably mounted on said bar, and grate teeth` on said y elements, at least the upper portions of said teeth being of curved outline longitudinally of such elements, whereby corners are eliminated at the upper' portions of said teeth and the opposing walls of adjacent teeth diverge at the top portions of said teeth, so that air flowing upwardly between the teeth spreads over the length of said elements, said teeth being dropped below the top edges of said elements a sufficient distance to provide passage for such air beneath a bed of coal on said elements.

CHARLES F. REGAN.

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