US1285671A - Stoker. - Google Patents

Description

J. S. S. FULTON.

STOKER.

APPLICATION HLED DEc.e. |917.

Patented Now'. 26, 1918.

3 SHEETS-SHEET l.

J. S. S. FULTON.

STOKER.

APPLICATION FILED DEC6, 19H. 1,285,671. Patented Nov. 26, `1918.

3 SHEETS-SHEET `2.

by] I J. S S. FULTON.

STOKER.

APPLICATION FILED DEc.6. 19H.

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JOHN S. S. FULTON, OF CHICAGO, ILLINOIS, ASSIGNOR TO UNITED STOKERS CORPORA- TION, A CORPORATION F ILLINOIS.

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Specification of Letters Patent.

Patented Nov.. 26, 1918.

Application led December 6, 1917. Serial No. 205,869.

To all @hom t may concern:

Be it known that I, JOHN S. S. FULTON,

Chicago, in the county ofjCook and State of' Illinois, have invented certain new and useful Improvements in Stokers, of which the following is a full, clear, and exact speeii-. cation.A

My invention pertains to the chain or traveling grate type of mechanical Stoker 1n which the fuel is'carried by the movement of the grate from a hopper located at the front end into the combustion chamber -of the furnace, where 1t becomes ignited, and the burning fuel is carried Slowly rearward until it is consumed and the ashes are carried over the rear end and permitted to fall into an ash pit.

The invention has for its object to provide new and effective improvements, in construction and operating mechanism, which will eliminate certain of the objectionable features of the traveling grate type of mechanical Stoker.

A further object of my invention is to provide such a construction and arrangement and movement of the grate that the effect of the destroying action of the furnace fire thereon will be reduced toa minimum, thereby requiring little or no repair, and small amount of power for efficient and continuous operation. f

In carrying out these objects, I have developed a novel construction and arrangement of a traveling grate Stoker and the mechanism for. operating same, which will be illustrated in the accompanying drawings, and described in the following specification.

In the drawings:

Figure 1 is a perspective view of my improved Stoker;

Fig. 2 is a vertical Section of the right half of my improved Stoker taken along the line 2-2 of Fig. 4;

Fig. 3 is an elevation of the left half of the front of the Stoker' with the exception of the geared reduction drive, which is shown in section through its center line;

Fig. 4 is a central longitudinal sectional elevation of the Stoker, parts being broken awa Fig. 5 is a side elevation, partly in section 4tion 28 of the ratchet wheel,

of he geared reduction drive for the grate; an

Fig. 6 is a perspective view of a grate bar or element.

Referring to the. drawings, yfthe Stoker frame 10 is shown as supported upon the wheels 11 mounted on the tracks 12,'on which the stoker may be` moved into and out of the combustion chamber of the furnace. The fuel hopper 13 supplies fuel to the upper surface of the grate 14 as the latter is moved slowly in frame 10 into and through the combustion chamber. Means,

such as perforate lugs 10, coperating with the stationary framework of the furnace, are employed to fasten the frame 10 and hopper 13 in operative relation to the combustion chamber.

The present practice with stokers of this type is to operate a battery of automatic stokers from a line shaft. The line shaft is driven by a small motor. or steam engine at a constant speed. Motion is transmitted from it to each individual Stoker by means of an eccentric which reciprocates the eccentric rod 15. In my improved operating mechanism, the Aclevis 16, mounted on the ratchet arm 17, receives motion from the rod 15, thereby imparting an adjustable intermittent rotating movement to the ratchet wheel 18 through the agency of pawls 19, mounted upon the arm 17. Additional pawls Q0, pivotally mounted on a stud :21 on the casing 22, prevent the ratchet wheel from having any backward movement. The line shaft speed being constant, a widle range of speed of the ratchet wheel 18 may beobtained' by an adjustment of the clevis 16, by rotating the hand wheel '23, thereby rotating the screw 24, on which the nut 25, forming part of clevis 16, is mounted. When it is desired to stop the operation of the stoker entirely, the pawls 19 are thrown out of engagement with the ratchet wheel 18. The ratchet wheel 18 is loosely mounted on the main Stoker shaft 26., and the sleeve portion 27 of the ratchet arm is constructed to rotate freely on an extending hub por- By this arrangement, all stress imparted to the ratchet wheel is only at such times as both ratchet wheel and arm are moving asm unit, thereby eliminating all possibility of wear between the two surfaces.F Gn the return movement of the ratchet' arm there is no work performed or stress imparted, and consequently no wear occurs.

In order to secure the proper ratio of speed between the rotation of the ratchet wheel 18 and the main stoker shaft 26, an intermediate gear 29 and pinion 30 are provided. This intermediate gearand pinion are rotatably mounted on the shaft 33 carried by casing 22. This casing is supported entirely by the journal box 34, and the entire reduction gearing is movable as a unit with the shaft 26 and box 34. The pinion 3l attached to the ratchet wheel 18 engages the gearr29, and its pinion 30 in turn engages the gear 32. which is securely keyed to the main stbker shaft 26, resulting in a slow intern'i'ittent rotating movement of the shaft 26 that in turn causes the slow intermittent movement of the grate. This movement ot the grate is accomplished by suitable sprocket wheels 86 keyed to the front and rear stoker shafts, 26 and 3T respectively. Two or more chains, as may be required (according to vthe width of the Stoker), are provided, composed of links 38 identical -in construction but designed to be held together by pins 39. These chains engage projections forming a portion of the sprocket wheels 36. Cross bars 40 ot standard T- section are bolted to corresponding links of these chains, and the grate elements4l are in turn bolted tothe cross bars 40. The grate elements 4l form the grate surface upon which the fuel is carried into the furnace from the fuel hopper 13, and upon which combustion takes place.

In order that these grate elements 4l may progress from the front to the rear of the stoker, while carrying the burning fuel, without any movement whatsoever in the relation of one to the other, and to provide a free means of travel from the front to the rear, and their return on the bottom from the rear to the front, rollers 42 and 48 are provided, mounted on the pins 39. rThe rollers 42 are grooved circiunferentially and engage the tracks 44, which are fastened to frame l() and extend the entire distance between the front and rear sprocket wheels directly under the upper run of each chain. lt is desirable that this track be constructed wedge-shaped. substantially asshown, so as to provide against the lodgment of ashes and cinders thereon. which would interfere with the rotation of the rollers.

During the movement of the grate elements 41. from the front to the rear, the rollers 42 only are employed` ther rollers 43 remaining idle. 0n the return movement of the grate elements (at the bottbm) the rollers 43 of a rhain engage the lower flange of the Zshaped track 45,`fastened to frame `the returning grate elements.

assenti l0, and the rollers 42 remain idle. fn order to prevent ashes and cinders from falling on this track andinterfering with the movement of the rollers, the plate or shield 46 is secured to the stoker framework in such a manner as to exclude them, substantially as shown. j r

The grate elements 41 are made in suitable sections and so constructed as to overlap adjacent sections or be in turn overlapped by adjacent sections, thereby eliminating any sifting of the fuel due to the expansion and contraction of the grate elements caused by the furnace heat. 4In order that these' grate elements may be easily and quickly removed and replaced by wrench, a square hole 47 is provided in each grate element through which square necked bolts 48 pass to fasten it to the cross bars 40, preventing turning when a wrench is applied to the nut. These grate elements are provided with positioning and spacing lugs 49 and 49a, which maintain the elements at a fixed distance from the cross bars 40, thereby permitting a" free circulation of cooling air between each grate element and its support, and reducing the liability off the cross bars becoming overheated and warped, the points of contact between the grate elements and the cross bars through which heat may be conducted being very small. Furthermore, these grate elements are mounted at one side of each cross bar and `overhang the space between adjacent cross bars, thereby giving an unobstructed path to the streams ot air required for combustion, and also removing the joints between adjacent grate 'elements from vertical alinement with the pins 39 and their bearings.

As the grate passes over the sprockets on the rear Stoker shaft 37 the grate elements one man with a single i.

become separated, and unless suitable means were provided the ashes from the furnace (which is intended to be carried into the ash pit at the rear of the entire Stoker) would fall through and lodge on the under side of To prevent this l provide the shield 50. The ashes and refuse fall down between the upper grates on this shield, and are in turn dragged rearward into the ash pit by the action of the cross bars 40. lt will be noted that by arranging the grate elements 4l so that they overhang the space between adjacent cross bars in the direction of movement of the grate, there is no tendency for ashes or refuse to be. caught by or collected in the under side of the grate and. carried toward the front end of the furnace.

i During the operation of stokers of this type a small amount of tine fuel may sift through properly constructed grate bars before the fuel becomes ignited. rThis unignited zone seldom extends more than twelve or fifteen inches inside the furnace; that is,

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' veyer beyond the stoker'gate forming the inner portion of the fuel hopper 13. Unless conserved, this fuel, however, will pass on through the lower or returning grate ele-V ments into the ash pit, where it will become mixed with the ashes and lost. Certain portions of the fuel may become lodged in the under side of the air spaces of the lower grate elements, clogging up said air spaces andvinterfering with combustion. To prevent this and conserve the fuel, I provide a shield or ho per 5l extending beneath the upper run o the grate a. sufficient distance to catch the fuel sifting through said grate. The collected fuel may be carried out' the side of the stoker by the action of a conscrew 52, which may be kept in constant rotation in any desired manner.

Great trouble, annoyance and expense are encountered with all stokers of this type due to clinkers adhering to the side walls, and the fuel burning out adjacent the side Walls before a like amount is consumed throughout the remaining portion of the furnace. The cause of clinkers adhering to the side walls is due to the natural aflinity of clinkers and rebrick when subjected to high temperatures.4 This/results in the projecting clinkers interfering with the proper feed of the fuel along the furnace sides, permitting large air holes todevelop which seriously affect the capacity nace. As this occurs constantly in standard types of stokers, the only remedy is to keep repeatedly breaking the projecting clinkers 0E with a large bar, introduced beneath the hopper gate. This is not only very laborious work, but the clinker being less refractory than the firebrick results in the destruction of the side walls in a short time, and the displacement of the ledge plates which are built into the side walls and necessary with all other stokers of this type.-

My improved stoker has been so designed that the burning fuel of the furnace does not come in contact with the fire-brick side walls, neither will the fuel burn any more rapidly along the sides of the furnace than throughout the remaining portion, and ledge plates are not required. This is accomplished by permitting theportion 53 of the grate area along each side to be devoid of any air space. This portion is fastened to the frame 10 and does not travel or progress-,- as in the case of the remaining grate area, mains stationary at all times. In order, however, to increasetheecctiveness in operation the gate of the hopper is preferablyV constructed so as to admit to the surface of the grate a larger-supply of fuel at each side than in the middle. In the course of a very short period of time, by this arrangement, fine, disintegrated ashes collect over the stationxarydead grate, and ,as the fuel hopper and hoppergate are narrower than the and efficiency of' the furbut rel width of the total grate area, and as the fuel as introduced into the furnace under the. hopper gate is thicker at the sides than in the middle, it will be seen that no burning fuel whatever comes in contact with the firebrick side walls, and that means are provided to supply an ample excess of fuel along eachside to cover the extra grate area. This Stoker is supplied with front take. ups. `(For taking up the wear and slack out of the chain.) This is accomplishedby adjusting the journal boxes 34'. and v34a in opposite sides of the frame 10 by means of. the adjusting screws 54. In view of the fact that the speed reducing driving gearing is mounted on the main stoker shaft 26, either 9u many changes and modifications may be made without departing from the spirit of i' the invention or its scope, as set Vforth in the accompanying claims. y

What I claim as new is:

1. In an automatic Stoker, an endless chain conveyer comprising a plurality of link menibers, anti-friction supports for said linksY in the upper run of said conveyer, independent anti-friction supports for the links in the lower run of said conveyer, both sets of anti-friction supports being mounted ico upon and movable with said links, fuel supy,

porting elements carried by said link mem, bers, and means for driving said conveyer. 2. In an automatic Stoker, a frame, two

parallel endless chains made up of a plurality of link members, supporting guides in said frame for said link members, cross bars connecting corresponding links in said iio parallel chains, grate elements, means for detachably fastening the grate elements to said cross bars, said grate elements being provided with spacing lugs separate from said fastening means for maintaining vthe grate elements a fixed distance from the cross bars thereby permitting a'free circulation of cooling air between each grate element and its supporting cross bar.`

3. In an automatic Stoker, a frame, an endless chain conveyer comprising a plurality of link members, supports for said "link members, fuel supporting elements carried by said link members, means for driving said conveyer, speed reducing gearing also mounted upon said frame and connected to'- iasl said driving means, and means for adjusting said driving means and speed reducing gearing bodily in said frame to take up the slack in said conveyer.

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4. fn an automatic stoker, an endless chain conveyer comprising a plurality of link members, supporting guides for said link members, fuel supporting elements carried by said link members, means including speed reducing gearing for driving said conveyer, and means for adjusting said driving means including said speed reducing gearing bodily to take up the slack in said conveyer.

5. ln an automatic stoken, a frame, an endless chain grate operatively mounted in said frame, and means for driving said grate including a shaft, and speed reducing power transmission ,mechanism connected to andy movable as a unit bodily with said shaft when the latter is adjusted laterally, and means fon-adjusting the shaft laterally in said frame to take up the slack in said grate.

6. ln an automatic stoker, a frame, upper and lower guide tracks carried by said frame, endless chains, each made up of a plurality of links, sprocket wheels for said chains at the ends of said frame, two sets of rollers carried by said chains, one set of rollers operating on the upper guide tracks and the other set of rollers operating in the lower guide tracks, fuel supporting elements carried by said links, said guide tracks and rollers being so arranged that each link has an anti-friction support during its forward and return travel.

7. ,ln an automatic Stoker, a frame,.guide tracks in the upper and lowerportions of said frame, endless chains, each made up of a plurality of links, sprocket wheels for said chains at the ends of said frame, rollers carried by said chains and operating on the guide tracks in the upper portion of the frame, another set of rollers operating n the track in the lower portion of the frame, fuel supporting elements carried by said links, said Guide tracks and rollers being so arranged that the links of the chain 'have anti-friction support during forward travel along the upper portion of said frame and also during retuin travel along the lower portion of said frame, and means for preventing the accumulation of ashes on the tracks in the lower portion of the frame.

8. in an automatic Stoker. a traveling grate comprising a plurality of chains,

cross-bars mounted upon the links of said chains and grate elements mounted rigidly -for adjusting said boxes to take taeter/i upon the cross bars, said grate elements being provided with lugs for attachment to said cross-bars, and additional lugs for spacing the elements from the cross-bars able as a unit therewith when the driving shaft is adjusted to take up the slack;

l0. ln an automatic Stoker, a frame, an endless traveling grate, a driving shaft therefor, bearing boxes in said frame, means up the slack in said grate, a train of speed reducing gears mounted upon one of said boxes and an. extension of said driving shaft, and movable as a unit therewith when, the driving shaft is adjusted to take up the slack, an oscillatory pawl arm and a ratchet wheel through which power is applied to said train of gears, the wheel having an extended hub upon which the arm is mounted so as to move as ay unit therewith when the grate is moved in the frame, and to rotate freely on said hub in a reverse direction when the grate is stationary.

ll. In an automatic stoker, a frame, an endless travelin grate, a driving shaft therefor, means for adjusting said shaft to take up the slack in said grate, and a train of speed reducing gears for driving said shaft from a source of power and movable as a. unit with the driving shaft as it is adjusted to take up the slack in the grate.l

l2. In an automatic stoker, a frame, a grate in said frame, an operating shaft for said grate, driving mechanism for said shaft including a ratchet wheel and oscillatory pawl arm, the wheel having an extended hub upon which the arm is mounted so as to move as a unit therewith when power is applied to the shaft and to rotate freely on said hub in a reverse direction when the shaft is stationary.

ln testimony whereof f affix my signature.

JHN S. S. FULTQN.

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