US1761029A - Traveling-grate stoker - Google Patents

Description

June 3, 1930. w, D R c ET AL 1,76L029 TRAVELING GRATE STOKER I I Filed June 12 1926 INVENTOR lA ILLJAM D. YERRICK Jams 14 P5021 WITNESS BY v I, Tm,

Q. i ATTNEY v Patented June 3, 1 930 WILLiAMgD. YEBRICK, oawo'mesmm iyiAssncnnsnr'rs, AND Jnss wrnc r, VCR-NEW YORK, N. Y., ASSIG pas TO RILEY sroxnza conroanrron, or wonensrnn, :iaAssA 'cHUsET'Ts; A CORPORATION. or ASS HUSETTS TR V LING- Application filed ifime '12 This invention relates to traveling grate stokers, and more particularly to traveling grate stokers in which the fuel supporting surfaces are carried on endless chains.

In stokers of this type'the fuel is fed onto the grate from a hopper usually arranged at the front of the furnace. The .fuelis then carried into the furnace, where combustion takes place, and the ash is deposited at the rear. The grate at this point loops down around some suitable support, and returns along the bottom of the stoker tothe front of the furnace. The fuel supporting members, or grate clips, separate to a certain extent in going around the support at the rear of the stoker, and this causes a part of the fine ash to becomeentrapped by the grate clips and car-1 ried on their inner surfaces in their-return path, to be eventually deposited'in'a heap at the stoker front. this point is very objectionable. It is. not only'unsightly, but also requires'frequent attention on the part of the operators to keepit removed. In many plants hoppers have been built beneath the front of the stokers'to, collect this material. Such hoppers add to the cost of installation, and takeup valuablelspace 1n the boiler house. 7 n.

It is accordingly one object of this inven tion to provide a traveling 'gratewhich, Will automatically deposit the incombustible inatter at the rear of the stoker inthe receptacle provided therefor, and in which the tendency for the clips to carry'the ash towards the front of the stoker is minimized.

The grate clips of traveling grate stokers are usually iron castings rather loosely fitted to their support. It frequently happens, therefore, that a clip will not fall properly into place as'it revolves about the driver at the front of the 'stoker, and so-travelsthrough tne furnace with one endprojecting above] the level of the other clips andinto' the fuel bed This causes the projecting clip to become rapidly burned. 'This conditionis aggravated by the enlarged air opening resulting from the displacement ofthe clip, wh ch permits a localized blast of air to lmp nge on'the fuel adjacent to said clip, accelerating combustion at this point;

Such an accumulation at GBATE 'sroxnn 1926. serial no. 115,622.

. It is accordingly another objectof this innecessary burning of the clips, and thus increase the life of the grate-surface.

In accordance with our inventioln'we provide a traveling grate stoker in which the fuel supporting members are so mounted as to form a, substantially continuous surface during their rearward movementinto the furnace and are so arranged that before returning to the stokerfront they will automatically as sume such a positionas to cause the major. portion of the ashes carried by them to be dee; posited in the ash pit or other proper recept-a'c'le', and minimize the accumulation of ashes r on the inner'surface of the clip. This is preferably accomplished by providing a pivoted support for the grate'clips, with stops to limit the extent of movement in either direction,

whereby the clips take a horizontal position when carrying fuel into the furnace, and as sumer a position atasubstantialangle to the horizontal when s'tartingback, so that the accumulated ash will easily-slide off. Ifrdesired, the-force' of gravity may be utilized to accomplish this result, by mounting each clip on a support spaced from its center of gravity in the direction oftravel, or otherwise producingv anvunbalanced condie In order to insure that eachclip will assume its proper position before passing'under the hopper, WG PItOVlCl'Q at this point a suitable ii'nember extendinig' across the width of the fuel supporting surface. This is so arranged that V any projecting V grate clips will strike,

.stolrerj-and' placed {closelyadjacent to the against it and thereby be forced into "place,

If desired; thisineniber may be pivotally mounted, so astobe held by gravity against the grate clips. ltma'y also be formed in a stoker.

, Fig; 1-.isalongitu dinal section} of a lstoker f plurality of sections across the width; ofthe illustrating one embodiment of our invention;

Fig. 2 is a perspective view of a supporting bar formed to carry a number of grate clips; Fig. 3 is a perspective view of a grate clip; Fig. 4 is a detail showing a grate clip mounted on the supporting bar; and

Fig. 5 is a perspective view of a grateleveling member.

The embodiment of our invention illustrated in the drawings comprises walls of suitable construction arranged to form a furnace. Mounted adjacent to the front wall is a fuel hopper 10 formed by a side frame 11 at each side of the stolrer and plates 12 and 14 placed between them. In order to control the thickness of the fuel bed, we may provide'an adjustable gate 15, arranged to be raised or lowered by rotating shaft 17. Adjacent to the gate 15 and inside the furnace, a suitable ignition arch 18 may be arranged to ignite the incoming fuel by heat reflected and radiated therefrom.

Beneath the hopper 10, and so placed as to withdraw fuel therefrom, is a substantially,

horizontal traveling grate 20, arranged to move slowly into the furnace and supply fuel for combustion. The grate is preferably composed of a number of individual grate clips 21, each clip being provided with a supportingarm 22 near its rearward end. If desired, slots 24- may be provided at each side,

to facilitate the passage of air between adjacent clips. The clips may besupported on suitable cross members, such as supporting bars or grate angles 25, each angle having at the ed e of one flange a substantially cylindrical bearing surface 26. It will be understood that these .grate angles extend across the entire width of the stoker, and each one supports a number of clips which are placed sideby side and are assembled by sllding them on from the ends of the grate angles.

The grate angles 25 are preferably sup ported on and carried by two or more heavy endless travelers, such as chains 28. The number ofthese chains may depend upon the width of the stoker. These chains may be driven at the front of the stolrer by sprocket wheels 29 mountedon shaft 30. Thisshaft may be supported by suitable bearings 1n the side frames 11, and is rotated in the direction shown by the arrow by any suitable.

source of power. At the rear, the chains may pass around stationary semi-circular tracks 32 mounted on a heavy girder 33. In'moving horizontally into the furnace, the chains may rest on tracks 85, and on their return they may be carried on tracks 36, in accordance with the usual practice.

Air for combustion may be brought in from the sides of the stoker into the space beneath the fuel supporting portion of the grate, whence it passes upward through the grate and the fuel bed. This space beneath the fuel bed is preferably divided into compartments by means of cross beams 38. Fine coal sifting between the grate clips may be collected on bottom plates 40 in each compart- 1'nen-t,and removed through suitable cleanout doors in, the side walls. Mounted on the rear girder 33, closely adjacent to the grate angles 25, and between the chains 28, are ash guards 42. between the clips where they first break apart to be caught on their upper surfaces and car ried toward the rear of the furnace. At the rear of the stoker we may provide a bridge wall 44, which forms the rear wall of an ash pit 45. In order to prevent leakage of air into the furnace through the space between the grate and the floor, we prefer to form a shallow pit and fill it with cinders to form a cinder-seal 46.

The grate clips 21 are so arranged on the grate angles 25 that they may rock freely about the cylindrical bearing surface 26. We prefer to allow approximately 45 degrees of movement, and it is evident from an inspection of Fig. 4 that the amount of revolution will be determined by the location of the shoulders 4e? and 18 on the arm 22. As the clips are carried downward at the rear of the stolrer, the center of gravity of each clip will be brought to the rear of its support, and the clips will revolve about the bearing 26 until the limit of this movement is reached as determined by shoulder 48. It is evident then that during their travel along the bot-- tom of the stoker, the clips will be held at an angle of approximately degrees with the horizontal. In passing over the cinder-seal 16, the clips are free to swing backward as they make cont-act with the cinders. At the front of the stoker the clips are carried upward around the sprocket wheels 29, and gravity will cause them to assume the position shown in Fig. I, as determined by shoulders 47.

Occasionally an individual clip in going around the driver or sprocket wheel 29 will not fall into position and will project above the grate; In order to overcome this difiiculty and prevent the subsequent burningof the projecting clip, we prefer to provide means at the stoker front to force every projecting clip into its proper position before it passes under the coal hopper.

These cause all iine ash which may-fall inis may be accompllshed by a member 50, arranged in that projecting clips will strike this member and assume their proper position.

In the operation of the stoker, fuel is gradually fed from hopper onto the moving grate 20 and beneaththe adjustable gate 15. As it passes into thefurnace, the fuel l is ignited by heat'reflected and radiated by V arch 18. Air passes'upvvard through the grate and combustion is completed as the fuel bed is carried towards thebridge wall. At the rear, the clips pass downwardaround the tracks 32, and revolve abouttheir bearings 26, so that when started on their return path they are in the positionshown in Fig; l, and

all ash which may have accumulated on their 7 surfaces is free to slide off into the ash'pit 45. The clips pass next over the cinder-Seal 7 4:6 and upward around sprocket wheels 29 at the front, where they assume their original positions, and any projecting clips are forced into place by contact with the member 50.

It will be evident tothoseskilled in the art that we have provided a very efiicient traveling grate ,stoker, in which-ash deposit at the stoker front and burning of the grate In this Way we ha-ve'eliminatedmu ch of the expense clips hasbeen reduced to a minimum.

and loss of time caused by replacement of the gratee'lements and-removal of ash accumulation at undesired points. Vlfehave,

moreover, done away with the necessity of installing expensive and bulky hoppers he neath the front of the stoker. I

Having thus described our invention, what We claim as new and desire to secure by Letters Patent, is: f

1. A stoker comprising a fuel hopper, an

endless traveler to carry fuel therefrom into j the furnace, fuel supporting members pivoted onsaid traveler, and means on sand mem bers to limit the pivotal movement thereof in; each direction so that the members will' eachendless traveler to carry fuel therefrom into afurnace, fuel supporting members loosely mounted on said traveler, and a movable member located in front of the hopper and arranged to rest'by gravity on the tops of said members as they pass successively thereunder and thereby force'any projecting fuel supporting member into the proper position before fuel is deposited thereon.

5. A stoker comprising a fuel hopper, an endless traveler to carry fuel therefrom into a furnace, fuel supporting members loosely mounted on said traveler, and a member piv otally mounted in front of said hopper and arranged to rest by gravity on the tops of the fuel supporting members as they pass successively thereunder and thereby cause the 7 members to form a substantially continuous surface before receiving the fuel from the hopper. j f

e 6. 'A stoker comprising a fuel hopper,'an

endless'traveler, fuel supporting members pivotally' mounted on the traveler, means to hold them in afuelsupporting position while travelin on the upper run and permit them to" turn and dump deposits thereon when travelingon the lower run, and means located in front of the hopper and close to the nori assume a fuel supporting posit-ion when movr 7 ing inwardly and will depend in 3 an ashdum Jin osition when returnin outwardl 1: v

load fuel thereon, fuelsupporting members loosely mounted on said traveler, and ameni- 2. A Stoker comprising. a fuelyfeeding hopper, an endless traveler to carry fuel therefrom into the furnace, grate clips,and

supports for the clips, said supports being secured to the traveler,- and said grate clips being pivotally mounted. on the supports and provided with shoulders so located that the 24;. A stoker comprising a fuel hopper, an

on its pivot to l if clips are held in a horizontal position when 7 traveling inwardly without'resting one on another,and depend under the influence of gravity when returning outwardly. V A stoker comprising anendless traveler to carry fuel into a 'furnace,a fuel hopper to ber mounted in frontfof the fuel loading posiof'the tops of said members so as to force any projecting members into the'proper position tion and arranged close to the normal path before fuel is deposited on them.

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