US1978106A

US1978106A - Extension grate

Info

Publication number: US1978106A
Application number: US615282A
Authority: US
Inventors: Clifford E Harrison
Original assignee: American Engineering Co Ltd
Current assignee: American Engineering Co Ltd
Priority date: 1932-06-04
Filing date: 1932-06-04
Publication date: 1934-10-23
Anticipated expiration: 1951-10-23

Description

0a. 23, 1934. c. E. HARR ISON 1,978,106

I EXTENSION GRATE Filed June 4, 1952 2 Sheets-Sheet l ATTORNEY Oct. 23,1934. c. E. HARRISON EXTENSION emvrs Filed June 4, 1952 2 Sheets-Sheet 2 N R0 M; p R mf Y as \\\\x t w m :L H Gig 1 1 w 3" w J K 1%.

ATTbRNEY Patented a. 23, 1934 .97am EXTENSION cane clieora E. Harrison, Philadelphia, 1a., assignor to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Application mi 4,11

Claims.

This invention relates to stoker furnaces, and more particularly'to the extension grates employed in such devices.

Extension grates, as is well known in'the art,

5 are positioned to the rear of-the retorts and tuyres of the Stoker and function to complete the burning of the fuel advancing thereto from the retorts and tuyeres and to feed the residue into the ash pit. These grates, during operation of t e furnace, are in direct contact with the incandescent fuel, and thus are subjected to extremely high temperatures and would deteriorate rapidly unless adequately cooled by the incoming draft air. of the extension grate be effectively cooled." In

order to obtain the best results it is also important.

that the fastening means provided on. the extension grates be removed from the heat of the furnace and to be so positioned thereon asto permit ready installation or removal of the. grate bars from the stoker and yet not obstruct the flow of air thereto. In order to reduce the maintenance cost' to a minimum the individual grate bars should be made as narrow. aspossible without detracting from the strengththereof or the emciency of theunit as a whole.

One object of thepresent, invention is to provide an extension grate bar which is so construct-- will be in contact with the incoming draft air and thus be maintained sufliciently cool to with stand the heat of the furnace.

Another object of the invention is to provide extension grate bars in which the fastening means thereof are removed from the hotzones of the furnace and so positioned as not to obstruct the flow of air through said grate bars.

A further object of the invention is to provide an extension grate bar of such dimensions that the heat absorbing surface thereof will be relatively small as compared with the heat dissipating surfaces which are constantly subjected to the cooling effect of the incoming draft air. I

A further object is to provide an extension grate in such a manner that the maintenance cost thereof will be reduced to a minimum.

.A further object of the present invention is to. provide an extension grate with a series of interlocking ribs to prevent siftings from pa therebetween.

A further object of the invention is to provide w an extension grate in which the individual units thereof are provided with reinforcing means remotely positioned from the hot side of said units,

thereby decreasing growth and distortion caused It therefore is important that all portions. T

932. Serial No. 615,282

by the variable temperatures to which said grate is subjected.

A further object is to provide an extension grate in such a manner that a smooth inclined surface will be presented to the fuel which produces a 39 slicing action of the fuel and also decreases the tendency of clinkers to adhere thereto.

A further object is to provide an extension grate in which the individual units thereof are free to expand without interfering with the proper operation of the unit.

. Other and furtherobjects will become apparent as the description of theinvention progresses.

Of the drawings:

Fig. 1 is a side elevational view taken through one of the retorts of an underfeed stoker showing the general arrangement of the fuel feeding elements and extension grates.

Fig. 2 is an enlarged side elevational view taken through one of the extension grates, showing-the manner in which the grate bars are supported and held in position;

3' is a,..-'-view taken on line 3--3 of Fig. 2 with some of the .gratebars removed to show the structure of the supports therefor.

Fig. 4 is a planview of one of the grate bars comprising the present. invention.

Fig. 5*is-a vie w taken on line 5-5 of Fig. 4.

Fig.6 is a. .view taken on line 6-6 of Fig. 4. I I "Iis'a view taken on line 7-7 of Fig. 2. 85

l igr'ii jis a view showing the construction of the'lower sidefof the end grate bars.

Referring to the drawings, 1 indicates the front wall of a furnace equipped with an underfeed sticker 2; having a plurality of alternately disposed retorts 3 and tuyere rows 4 extending lengthwise of the stoker and inclining downwardly from front to rear thereon Fuel is supplied to the stoker from hoppers 5 which communicatewith a series of cylinders 6, each having a fuelfeeding ram '7 mounted therein. The rams 7 are actuated by any suitable power mechanism indicated at Sand upon each reciprocation thereof} predetermined. amounts of fuel entering the cylinders 6 from hoppers 5 are fed to the retorts 3. Suitably mounted in the bottom of each retort are a series of pushers 9 which underfeed the fuel along said retorts to extension grates 10 which in turn overfeed the consumed fuel to an ash pit 11 where it may be removed by any suitable apparatus (not shown). The pushers 9 and extension grates 10 are also actuated by the power mechanism 8 through the connections indicated generally at 12. Inasmuch as the sneciiic rrneans for actuating the rams, pushers and extension grates forms no part of the present invention, a detailed description thereof is unnecessary.

For the purpose of illustration, but one retort 3, row of tuyeres 4' and extension grate'section are shown, it being obvious that any number may be employed.

It is to be understood that any reference to the front or 'rear portions of the elements shown herein indicates those portions extending toward the front or rear of the stoker.

The extension grates comprising the present invention are arranged in groups, each group being supported on a. separate framework 14 which is mounted for reciprocation atthe rear end of the stoker.

Referring to Figs. 1 and 2, it is seen that the rear end of the stoker is supported upon an I beam 15, extending transversely of the furnace and supported at the ends thereof 'in any suitable manner in the side walls of the furnace. Positioned beneath and. to the rear of I beam 15 is a second I beam construction 16, which also extends transversely of the stoker. The lower grates 17 are supported upon a series of plates 18 extending upwardly from beam 16 and to the upper edge thereof are bolted a series of top plates 19. These plates are provided with an opening extending longitudinally thereof through which draft air from chamber 100 may pass to extension grates 10. Supported on top plates 19 are a series of guard plates 22, each of which also having a longitudinal opening 23 provided therein which registers with openings 20 provided in plates 19. The forward edge of each guard plate 22 is provided with an extension 24 which extends beneath a flange 21 provided in plate 19 and a key member 25 retains the guard plate in locked relation with top plate 19, as shown in Fig. 2. Bolted to I beam 15 and extending rearwardly thereof are a series of brackets 26', each of which having a longitudinal groove 27 provided along the upper edge thereof for guiding the extension grate supporting framework 14.

The framework 14 for supporting a group of extension grates 10, comprises a pair of substantially triangular shaped

side walls

30 and 31. A casting 32 extends between

walls

30 and 31 and is bolted tosaid-walls at the upper ends thereof as shown in Figs. 2, 3 and 7. This casting is provided with a series of spaced vertically extending projections 33, the purpose of which will be fully described hereinafter. A .circular aperture 34 is also provided in casting 32 intermediate the ends thereof for receiving the reduced portion 35 of connecting rod 36 which, as was pointed out before, constitutes one of the operating connections between the power mechanism 8 and extension grates-10 for reciprocating the latter during operation of the stoker. Connecting rod 36 is secured to castings 32 by a pin 37, as shown in Fig. 2, and is guidecl'in an aperture 38 provided in a plate 39 extending transversely of the stoker between I beam 15 and coal plate extensions 40. Also bolted to

side walls

30 and 31 is a casting 41 which,'as shown in Figs. 1, 2 and 3, is provided with a substantially cylindrical locking member 42, and a member 43 spaced therefrom. A series of spaced ribs 44 extend between members 41 -and.42, and are provided to properly space the individual extension grates 10, as will presently appear- The lower edge of

side walls

30 and 31 rest upon the upper surface of guard plates '22 and the forward portion of said lower edges extend into the fuel bed. 1

the grooves 27 provided in brackets 26. The

framework 14 is thus guided in its reciprocatory movement during operation of the stoker.

Each extension grate bar 10 comprises an upper horizontal portion 45, an intermediate inclined;

portion 46, and a substantially vertical lower portion 47. The upper surface of portion 45 is substantially flat and is provided with a pair of laterally extending flanges 48 and 49 which in assembly overlap the corresponding flanges provided on the adjacent grate bars as shown in Fig.

7. The lower side of portion 45 is provided with a substantially T-shaped locking member 50, so constructed that when a grate bar 10 is assembled on the framework 14 the web 51 thereof will lie in the space between adjacent. projections 33 of casting 32 thus preventing lateral movement of the bar. The head portion 52 of locking member is adapted to engage projections 33 so that longitudinal movement of the bar is also prevented.

' The inclined portion 46 of each grate bar 10 has a relatively narrow fuel abutting or heat absorbing surface 53 and relatively wide side or heat dissipating surfaces54 and 55 extending forwardly 103 therefrom. A reinforcing rib 56 defines the lower edge of said portion 46. A series of spaced substantially horizontal projections 57 and 58 are provided on surfaces 54 and 55 respectively,'the former of which extend substantially to the fuel 105 abutting surface 53 while the latter terminate inwardly of surface 53 a distanceequal to the length of projections 57. Projections 57 are provided with beveled surfaces 59 and 60 at the front and rear ends thereof. Projections 58 are likewise 110 provided with beveled surfaces 61 and 62'at the front and rear ends thereof respectively, and in assembly the beveled surfaces 60 and 61 will abut against eachother and the upper and lower surfaces of said projections respectively will lie in the 115 same planes, thus forming relatively long passages through which draft air from chamber 100 may pass to the fuel bed.

Extending downwardly from rib 56 intermediate the ends thereof is a substantially T-shaped 1% hook member 65. In assembly the substantially arcuate portion 66 of hook engages locking member 42 of casting 41 and the head 67 thereof engages in the space providedbetween ribs 44. Thus both vertical and lateral movement of bar 125 10 is prevented.

The substantially vertical portion 47 of each grate bar 10 also has a relatively narrow fuel abutting or heat absorbing surface 70 and relatively wide

heat dissipating surfaces

71 and 72, respec- 133 tively, extending forwardly therefrom. These surfaces terminate in a reinforcing rib 73 which is a continuation of rib 56 provided on intermediate portion 46. A seriesof substantially horizontal ribs 74 and 75 are provided on surfaces 71 135 and 72, respectively, which in assembly lie insubstantial abutting relation with the corresponding ribs of adjacentgrate bars 10, thus defining air passages through which draft air may pass to i Referring particularly to Fig. 2, it is seen that the lower surface of coal plate extensions 40 overlie the upper surface of portions 45 of grate bars 10. These elements are spaced slightly apart so as to permit draft air to flow between them. It will also be noted that the lower edge of the vertical portion 47 of each grate bar 10 is also spaced slightly from the upper surface of plates 19 and 22 so that draft air may also pass between these elements. By supporting the grate bars in this manner it is apparent that, free expansion or growth thereof may take place without interfering with the adjoining elementsor the operation of the unit. All of theextension grate bars ofeach group are similar in construction with the exception of those provided at the extreme ends of the framework 14.

Referring to Fig. 3,, it is seen that end bars "76 are provided with a series of apertures '77 through which draft air may pass. The lower edge thereof, as will be seen by reference to Fig. 8, is provided with a longitudinally extending roove '18 which receives the upper edges of

side wall

30 or 31. Each bar is provided with a pairof hooks '79, one of which engages member 42 of casting 41 in a manner similar to those provided on the ,other extension grate bars of the group. The

purpose of providing two hooks is to make these bars of standard construction so that they may be assembled on either the right or left hand side .walls of the framework 14.

It will be noted that the walls of groove 78'are corrugated. This construction, obviously, insures the passage of air to apertures '77 from chamber 100 even in case the walls of groove 78 should lie in close juxtaposition to side walls or 31 of the framework 14. 1 i I In assembling the grate bars 10 and 76 upon the supporting framework 14, an end bar '76 is first placed upon the right hand side wall 31.

The substantially are shaped portion of a hook 79 of this baris brought intoengagement with the locking member 42 of casting 41'and the groove 78 provided along the lower edge thereof is then fitted over the upper edge of the side wall 31. The next adjacent grate bar 10 is then placed on the frame 14 by first bringing the arcuate portion 660! its hook 65 into engagement withthe locking member 42 of casting 41 and then lowering the forward end of thebar so that the web 51' on the lower side of portion 45 thereof, will enter into 'the space between'adjacent projections 33of casting 32; 'Ihe remainingbars are then assembled on the framework 14 in a similar manner. The laterallyextending flanges 48 and 49 of each bar overlap the corresponding flanges provided on adjacent bars as shown in Fig. 7, thereby forming a seal which prevents sittings from passing therebetween. This lap joint also prevents air from beingdischarged vertically in the vicinity of coal plate extensions 40. Air discharged vertically at these points would obviously increase the rate of com-- bustion to such an extent that serious damage to extensions 40 would result. The overlapping ribs or projections 5'7 and 58 extending from surfaces 54 and 55, respectively, of adjacent grate bars which mm long air passages between the bars, also prevent siftings from passing therebetween. After the grate bars have been thus assembled on the Supporting framework the coal plate extensions 40 are placed.v in position and the rearward end thereof retains the forward end of the extension grate bars against vertical movement. The hooks 65 provided on each of the extension grate bars engage locking member 42 of casting 41 and also prevent vertical movement thereof.

1 Draft air from the chamber positioned beneath the extension grates 10 flows in thedirection of thearrows shown in Figs. 1 and 2, and comes in contact with substantially the entire outer surface of each bar, thus maintaining the same sufficiently cool to withstandthe intense heat of the furnace. It is also to be noted that 'tal ribs provided on each sideof said the exposed surface of each extensiongrate bar 10 is relatively small as compared with the heat,

dissipating surfaces thereof, and thus the heat conducted, through the bar is readily absorhefl by the incoming draft air.

It will also be observed that the reinforcing

ribs

56 and 73 of each grate bar 10 are removed from the exposed surface thereof. By ar- 1 ranging the ribsin this-manner the grate bars 10 willhave greater strength and-the distortion thereof due to growth and uneven expansion caused by the variable temperatures to which a said bars are subjected will-,be greatly minimized.

The fastening books 65 and '79 are also provided at points remote from the hot zone ofthe grate bars and thus cannot be damaged sufficiently to destroy the locking effect thereof or render it difficult to remove the'grate bars from theframework. These hooks are also so pcsitioned'on the grate bars as not to interrupt the new of air ;to any portion thereof. Also, by the present con-' shown and described herein, but only by the scope of the claims which follow. u s.

. What is claimed is:

l. A grate bar of the class described, comprise ing an inclined body portion having a' relatively narrow heat absorbing surface, and relatively wide heat dissipating surfaces, a*series of substantially horizontal ribs provided on each of said heat dissipating-surfaces, the ribs provided on one of said-surfaces extending from substantially the upper edge of saidbody portion to a point intermediate the upper'fi'and lower edges thereof, the ribs provided onanother of said heat dissipating surfaces extend n from substantially the point at which said first mentioned ribsterminate toward the lower edge of said body portion, and locking means provided on said body portion.

2. A grate bar of the class described, compris ing an upper substantially horizontal portion, an intermediate, inclined portion, and a lower sub-' stantially vertical portion, flanges extending lon-, gitudinaily of said upper portion, a series of substantially horizontal ribs provided on each side. of said inclined portion, the ribs provided on one side of said inclined portion extending from the upperedge to a point intermediate its upperand' lower edges, the ribs on the other side extending from the point, at which said first mentioned ribs terminatetoward the lower edge of saiddnclined.

portion, a plurality. of ribs on said vertical portion, reinforcingmeans on said intermediate and lower portions, and locking means on the under side of said upper and intermediate portions.

3. Agrate bar of .the class described, comprising an inclined body portion, a longitudinal groove provided in the underside of said bodyportion adapted to receive the upper edge of a supporting framework, a series of substantially horizonw tion, the ribsprovided on one side thereof extending from the upper edge-thereof to .a point intermediate its upper and lower edges, and the lower edge of said body portion.

4. A grate bar of the class described, omprising an upper substantiallyhorizontal por ion, an intermediate inclined portion, and a lower substantially vertical portion, flanges extending longitudinally of said upper portion,=a longitudinal groove provided in'the under side of said intermediate portion adapted .toreceive the upper edge of a supporting framework, a series of substantially horizontal ribs provided on both sides of said intermediate portion, and locking means depending from said intermediate portion.

5. A grate bar of the class described, comprising an upper horizontal portion, an intermediate inclined portion, and a. lower substantially vertical portion, a longitudinal groove provided in the under side of said upper and intermediate portions adapted to'receive the upper edge of a supporting framework, a series-ofapertures extend- .ing through said intermediate portion from the 'top side thereof to said grooved portion through which draft air maypass, a plurality ofribs projecting from the sides of said intermediate portion,-. and locking means provided on said intermediate inclined .portion for securing said grate bar in position; i

6. An inclined extensiongrate comprising in combination a supporting framework consisting of a pair of substantially triangular, spaced side walls, a pair of spaced"l ocking\members' extendirig transversely between said walls and secured at their ends thereto, and a series of grate bars disposed sideby side each having an upper substantially horizontal portion, an intermediate inclined portion, and a lower vertical portion, flanges on each side of said horizontal portion extending longitudinallythereof, the flange on one. side of ,eac'h bar overlapping the flange on the adjacent side of the next bar, a series of substantially horizontal ribs provided oneach side of the-intermediate portion of each bar, the series of ribs on one side being spaced forwardly or rearwardly'relative to the series of. ribs on the other side so that the ribs on adjacent sides of adjacent bars coact to form long continuous air passages, and locking means provided on the under side of both the horizontal and intermediate portions of each. bar, said. locking means coacting with said spaced locking members to operatively position and 'hold said bars on the supporting framework. q

7. An inclined extension grate comprising in combination a supporting framework consisting of a pair of substantiallytriangular spaced side walls, a pair of spaced locking members extending transversely between said-walls and secured at their ends thereto, a series of intermediate grate bars disposed inside by side relation, and I; on the other side so that the projections on one side of each bar overlapping the flange on the adjacent side of the next bar, a series'of substantially horizontal ribs provided on each side of the intermediate portion of each bar, the series of ribs on one side being spaced forwardly or rearwardly relative to the series of ribs on the other side so that the ribs on adjacent sides of adjacent bars coactto form long continuous air passages, lockingmeans provided on the under sides of both the horizontal and intermediate portions of each bar, said locking means coacting with said spaced locking members to operatively position and'hold said bars on the supporting framework, and longitudinal grooves provided in the horizontal and intermediate portions of said end bars for receiving the upper edge of said side walls whereby said grate bars present a continuous unbroken surface over the entire width thereof.

8. A grate bar of the class described, comprising an inclined body portion having a relatively narrow heat absorbing surface and relatively wide heat dissipating surfaces, a series of projections provided on each of said heat dissipating surfaces, the projections provided on one of said surfaces extending between the upper edge of said body portion and a point intermediate the upper and lower edges thereof, the projections provided on another of said heat dissipating surfaces extending substantially between the point at which said first mentioned projections terminate and the lower edge of said body portion, and locking means provided on said body portion.

9. A grate bar of the class described, comprising an upper substantially horizontal portion, an in termediate inclined portion, and a lower substantlally vertical portion, a series of projections prov ded on each side of said inclined portion, the projections provided on one side thereof extending between the upper edge and a point intermedlate its upper and lower edges, the proections provided on the other side extending substantially between the point at which said first mentioned projections terminate andthe lower edge of said inclined portion, and locking means on the under side of said inclined portion.

10. An inclined extension grate comprising in combination, a supporting framework consisting of a pair of spaced side walls, a pair of spaced locking members extending transversely between said walls and secured at their ends thereto, and

'on the adjacent side of the next bar, a series of projections provided on each side of the intermediate portion of each bar, the series of pro-- jections on one side being spaced forwardly or rearwardly relative to the series of projections jacent sides coact to form passages for draft air, and locking means provided on the under side of each bar, said locking means coacting with said locking members to operatively position and hold said bars on the framework.

. CLIFFORD E. HARRISON;