US1497823A - Stoking mechanism - Google Patents

Description

june 17,1924,

J. G. woRKER STOKING MECHANISM Filed Oct. 3o 1920 2 sheets-sheet .1,

IN VEN TOR.

W I TNESSES: @www ATTOREY l l june 17 '1924.

Filed oct. 3o.

ATTORNEY Patented .lime 7, 1924.',

NrrED TES JOSEPH Gr. WORKER, OF EAU CLAIRE, WISCONSIN.

STOKING MEGEANISM.

Application filed October 30, 1920. Serial No. 420,663.

To all whom t may concern:

Be it known that I, JOSEPH G. WORKER,y

acitizen of the United States, and a resident of Eau Claire` in the county of Eau Claire and State of lVisconsin, have invented a. new and useful Improvement in Stoking Mechanism, of which the following is a specification.

This invention relatesto stokers and particularly to that class of stokers known as :mtomatic stokers commonly used in heating steam boilers. Such stokcrs usually comprise an inclined combustion grate supplied with fuel at the front end either by overfeed or underfeed mechanism or both, the combustion grate beingusually supplemented by a pivoted diunp grate closing the dumping opening at the lower and rear end of the grate between the lower end of the combustion grate and the customary bridge wall of the furnace.

In the usual type of furnace the mixture of ashes and slag accumulating ower the dump grate adheres firmly to thebridge wall. This accumulation interferes with` the proper operation of the'dump grate and the combustion of the fuel at the rear of the furnace and must therefore be dislodged at quite frequent intervals. The slag adheres !'irmly and occasions much difficulty in its removal, necessitating severe manipulation with a heavy iron rod or paddle. The frequency and severity of the operation does appreciable damage to the bridge wall necessitating expensive repairs thereof which occasion costly delays in the operation of the plant.

The principal objects of this invention are the production of a stoking mechanism in which the accumulation of slag adjacent the bridge wall is substantially prevented; the production of a stoking mechanism wherein the fuel usually wasted at the rear end of the furnace is burned; the production of a stoking mechanism wherein the fuel is properly manipulated automatically so as to cause complete combustion of the fuel with a minimum production of slag; the production of an automatic stoking mechanism that requires comparatively little manu'al labor in keeping the ash discharge open and free from sla-g accumulation; the production of an improved dump grate mechanism whereby combustion is facilitated at the rear of the furnace; the production of an improved dump grate which is substantially self-cleaning and therefore practically free of slag deposits; the production of.

means in connection with a dump grate for preventing burning of the grate, and suchv other objects as may hereinafter appear. Certain embodiments of the invention are *illustrated in the accompanying drawings "-wherein Fig. 1 is a partial plan view in part dia.- grammatic of the rear end o-f a furnace showing the improved dump grate mecha- 'nism with portions shown in horizontal section;

Fig. 2 is a vertical section in part diagrammatic through a furnace on line II--II of; Fig. 1;

F ig. 3 is an enlarged vertical section showing grate operating mechanism; and

Fig. -1 is an end view of a valve used in connection with the'cylindrical dump grate.

This invention relates particularly to dump grate mechanism used in connection with a well known type of underfeed automatic Stoker. Such a stoking mechanism is illustrated in F ig. 2, wherein the fuel is fed into a hopper 1 and is passed into a furnace through a passage 2 by means of a reciprocating plunger 3 operated by a motor 4 which continuously rotates a shaft 5 and with it a crank 6.' The plunger 3 is connected to the crank 6 by means of a link 7 which reciprocates the plunger back and forth at each revolution of the shaft 5.

After passing through the passage 2, thev fuel enters a number of fuel troughs 8 ar- -ranged in parallel relation with tuyre boxes 9 between them. The coal is therefore fed from beneath the burning surface, yand air is supplied tothe fuel bedI through the openings in the tuyere boxes communicating with a wind box 10 arranged beneath the grate construction. The wind box l0 is supplied with a blast of air through a pair of verticallydisposed conduits 10a (Figs. 1 and 2). The grate4 mechanism just described is usually supplemented by a moving grate 11 which, v in some furnace constructions, is adapted to' bey reciprocated from and toward the l tuyre boxes by lany suitable mechanism operated by the motor shaft 5. The air supplied to the grates just described is controlled by butterfly valves l2 arranged in various places in the wind box 10.

At the rear end of the furnace, a bridge wall 13 is separated from therear end of the movin grate 11 so as to provide a refuse pit or umping opening 14 between the moving grate and the bridge wall throu h which ashes and other residue from the uel may bel discharged. In the refuse pit 14, a plurality of cylindrical dump grates 15 are dis posed longitudinally thereof and are preferably situated beneath and at the rear of the rearmost active grate 11 so as to receive the material discharged therefrom. These cylindrical grates are closed at their ends Yand are pivoted for rotation upon a hollow trunnion shaft 16 extending entirely across the Width of the furnace or transverse to the direction of flow of the fuel. The trunnionshaftc 16 is mounted inl hollow bearings 17 and, 1s provided with two sets of perforatlons 18 and 19, the former beingv disposed so as to discharge into -the interior of the cylindrical grates 15, and,the latterl per` forations are adapted to communicate with chambers 20 in the hollow bearings 17 so that air supplied to the bearing chamber 20 through the pipe 21 may enter the interior of the trunnion anddischarge through the openings 18 or from the other end of the trunnion into the chamber 20 and out through the conduit 2.2. The purpose 'of such circulation of air through the trunnion shaft 'will .hereinafter appear.

The cylindrical dump grates 15 are hollow, the c lindrical shells thereof being pro# vided wit ports or perforations 23 through which air supplied lto the interior of the `dump grates' may be discharged in to contact with the material supported upon the cylindrical dump grates 15. It isthe object of these perforations to supply a blast of air tothe ash deposited on the upper surface of the dump grate. In order to economize the air and sup ly itonly to that por-Y tion of the surface o the cylinder in contact with the ash, the interior of the cylindrical dump grate is provided with asegmental cylindrlcal valve 24 carried upon the trunnionvshaftl 16 by means of bearings-or webs 25 integral with or secured to theA valve 24. .An end view of this valve is illustrated in Fig. .4 which shows that the cylindrical portion thereof extends through an arc of morev than ,180 and as shown in Fig. 2 prevents the escape of air `through any perforations 23 except those between the points a and b which are uncovered by thevalve.l It will be seen that i'f'the valv324 is held stationary and the dump grate 15 rotated, the ports`23 located around the perforations of the dump grate will be successively opened at the point *a and closed at the point b so that air only escapes through the points of the cylinder in contact with the mixture of `fuel and ashes. By reason of the blast of air which f may pass through the perforations any combusti le naterial remaining in the ashes will be consumed. v v

The trunnion shaft 16 is 4supported upon rocker arms 27 which are-keye 28 extendin parallel with the dump grate, this shaft emg mounted for rotationin. suitable` bearings 29 carried lupon I-beams 30 which beams serve to support the rear end of the furnace structure.- The shaft 28 is adapted to berocked or oscillated by end of the furnace where' itis provided with a hand wheel' (not/shovim)l whereby the worm 32 maybe manipulated. e When it is desired to dumpthe grate, the worm 32 is actuated vso as to move the worm-.gear 31 counterclockwise, which action will lower the trunto a shaft means of aworm gear segment 31 which is meshed with a worm 32 leading to the front nion shaft 16 and with it the dump grateso' ffas to dump the furnace whenever itis desired. 'It will be seen that by this mechanism the relative position o'f the dump grate with respectv to the moving grate 11 can be r -which extends forwardly of theJfurnaoe and is pivotally connectedto a bell crank leverl 37 pivotally carried by a-bracket 38 secured of the furnace. The forward arm of the rocking lever 37 is pivotally connected to a yielding link connection 40 which is pivoted at its upper end to the crank 6, operated by the motor 4. The yielding connection 40 may be of any ,suitable construction and as shown consists of telescoping members 44 and '45 and a spring 46subject to compression upon the imposition thereon of a load greaterv than a predetermined `safe load. The link 36 is supported between thev bell crank 37 and the rocking lever 35'v by means of a link 41. It will be seen from the foregoingthat, for each revolution ofthe crank 6, the rocking lever 35 will; be oscillated back and forth once and with each oscillation the weighted pawl 34 willratchet over certain dump grate 15 will be intermittent y rotated counterclockwise.

The rotation of the Idump grate intermittently toward the bridge 4wall causes the ash -to the I-beam 39 supporting the frontend teeth of the ratchet wheel 33 so that for each oscillation of the lever 35 the c lindrical ias tobe agitated and movedtoward the bridge.'

:wall and finallyfdischarged into the ash pit beneath the dumpmg grate. Any clinkers toolarge to normally pass over the dump "subsequently through the cylindrical grates 15. Any excess of air is returned to the wind box 10 through the conduits 22, previously 'referred to. This circulation of air prevents any overheating of the trunnion shaft and the cylindrical dump grate 15 and therefore the dump grates are not liable to be burned out.

The trunnion shaft 16 is preferably rotatable in bearings 17, and the bearings of the valves 24 preferably have loose fitting collars 42 embracing the trunnion shaft 16. llt is also desirable to provide the valves 24 with counterweights 43 (Fig. 4) so that they may be held by gravity in the position i1- lustrated in Figs. 2 and 3.

While I have shown my invention in two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and' 1 desire, therefore, that only such limitation `shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

1What I claim is 1. A dump grate for stoking mechanism comprising a moving hollow grate member provided with ports for the passage of fluid through the member into contact with the material on the surface thereof, and a valve closing such ports as do not discharge into contact with said material.

2. A dump grate for stoking mechanism comprising a moving hollow grate member having a single chamber provided with ports extending through the shell of the member exposed to contact with combustible materials and communicating with the interior of the grate member, means for supplying fluid to the interior of the grate member, and means closing such ports as do not discharge into contact with said niaterial. l

3. The combination with a stoking mechanism of a combustion grate, a refuse pit at the rear of the combustion grate, a moving hollow dump grate adjacent to the combustion grate and adapted to receive and to convey material discharged from the combustion grate, said hollow dump grate having ports for delivering fluid to the material supported thereon, means for intermittently moving the dump grate, and means closing such ports as do not discharge into contact with the material during the movement of the dump grate. 4. The combination with a stoking mechanismhaving a combustion gra-te terminating adjacent a dumping opening, of a rotary1 dump grate in said opening adjacent to said combustion grate, means for actuating said dump grate for elfectingl an intermittent movement of the ash-supporting surface contiguous to the plane of the combustion grate, and means for bodily moving the dump grate substantially transversely to the' plane of the combustion grate.

5. A stoking mechanism comprising in combination, a combustion grate, afstop member spaced from the discharge end of the combustion grate to form a dumping opening, a cylindrical dump grate in the opening, means for rotatingthe dumping grate so as to convey material from the combustion grate and crush it downwardly between the stop member and the dumping grate, and means for bodily swinging said cylindrical dumping grate downward y out lof the path of the material passing through the dumping opening,

6. A stoking mechanism comprising in combination, a combustion grate, a stop member spaced from the discharge end of the grate t0 form a dumping opening, a cylindrical dump grate in said opening adjacent to the combustion grate, spaced from the stop member and adapted to receive ash discharged from the combustion grate, means for rotating the dumping grate to move ash toward said sto-p member, and means for bodily adjusting the position of the dump grate with respect to the stop member.

7. A dump grate for a stoking mechanism comprising a rotary hollow cylinder, means for supplying fiuid to the interior of the cylinder, the shell of the cylinder having ports for the discharge of fluid therethrough, and a valve for closing certain of said ports, so as to secure uniform directional discharge through the open ports during the rotation of the hollow cylinder.

8. A dump grate for stoking mechanism comprising a rotary hollow cylinder, means for supplying fluid to the interior of the cylinder. the shell of the cylinder having ports for the discharge of fluid in the cylinder through the grate 'surface thereof, and valve means closing each 'of the ports duringl a predetermined arcuate travel of the rotating cylinder.

9. Stoking mechanism comprising in combination, a combustion grate, means for feeding fuel to the grate, means for operating the fuel feeding means, a hollow rotary dumpgrate cooperating with the combustion grate, means for rotating the dump grate actuated bvthe said operating means, said hollow dump grate having ports for the delivery of fluid to the material-passingv ing aim to'the interior of the dump grate from the said air supply passage, and means for discharging air from the` dump grate into the said @wind box.

combination a combustion grate discharging v into a refuse pit, a stop member spaced from the discharge end of the combustion grate so as to provide a dump opening into the refuse pit, a rotary dump grate at one side 13. A dump grate for fuel stoking mecha. ni'sm, comprising a hollow perforated trun'- nion shaft, a rotar hollow dump grate supported in said sha t and having ports in the portion of the shell thereof in contact with the combustible fuel, a valve carried by' the;

trunnion for closing certain ports in the dump grate shell, and means for holding the valve in a predetermined positione 14. A dump grate for a stoker comprising 11. Stoking mechanism comprising in; a hollow cylinder having peripherally discombination, a combustion grate, a wind box posed ports, means for supplying fluid to for supplying air to the rate, an air supply the hollow cylinder, means for rotating the passage leading to the windbox, a hollow` cylinder, a segmental cylindrical member dump grate cooperating with the combusdisposed within the hollow cylinder and artion grate, means connecting the interior of ranged to close ports which in the rotation the vdump grate with the said. air supply pasof the hollow cylinder are not in a position sage and`means connecting the interior of Jto discharge fluid into contact with the mathe dump grate with the wind box whereby terial supported by the hollow cylinder. air may passv from. the supply passage In testimony whereof, I have hereunto through the dump grate and into the said subscribed my name this twenty-fifth day of wind box. p October, 1920.

'12. Stoker mechanism comprising 7in JOSEPH G. WORKER.

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