US1463300A - Automatic stoker - Google Patents

Description

' L46300 l.. R. s'rowE' AUTOMATIC STOKER Filed June 1e j 1919 5 sheets-sheet 2 July 31, 1923. l

l.. R. sTowE AUTOMATIC sToKER' i File@ June' 16.' 191s;- s sheets-,sheet 5 July 31, E923.

. L. R.v STOWE AUTOMATIC sToKER Filed Junejle. 1919 #2236551? ZE. /jfozzz y5 Sheets-,Sheet 5 sof f being Application led June 18, 1919. Serial No. 304,584.

'To all whom z't may com em.'

' Be it `known that I, Lern R. Srown a citizen of the United States residing at Maplewood, in the county of t. Louis and State of Missouri, have invented certain new and useful Im rovements in Automatic Stokers, of. which die following is a specification.

This invention relates to improvements in stokers, and its purpose is to provide an improved automatic stoking devicein which the under-feed principle is combined lwith means for securing a positive feed Aof the fuel throughout the length of the grate.

It is we known that in the ordinary under-feed Stoker, it is impossible to secure a uniform and sitive movement of fuel toward 4the disc arge end of the grate or to secure and maintain a uniform condition of the fuel bed especially when thin lires are carried. t is well known that inthe usua type of underfeed Stoker a large quantity of fuel containing hlgh percenta of combustibles reach the discharge en of thestoker, where, for the sake of economy, it must be held untilzfthe combustion is nearly completed, while .other parts of the fuel reach the dischar e end o the grate uite well.consumed,an for the purpose o avoiding clinkers these' other vparts must be immediately discharged to the ash it. The diculty caused by this irreguljarity is increased by the absence in the usual under-feed stoker of a positive and continuousfmeans of discharging the refuse. These .defects in the under-feed stoker have been overcome in the present invention by combining a plurality of under-feed devices with a p ura ity vof grate chains which are arranged in alternation, so that the fuel which is moved upwardly by the under-feed devices is positively moved along the grate by the movlng chains, thereby securing a positive feed of the fuel from one end of the grate to the other and a positive discharge of the ash at the lower end of the grate. B means of the present invention, it is possigle to adjust the movements of the underfeed devices and the moving chains in order to secure any desired depth and condition gf the fuel over any part ofthe grate surace. Y

The nature of the invention and the various objects to be attained thereby will be understood from the following specification,

taken'in connection with theaccompanying.

drawings, in which one embodiment is illustrated.

In the drawings- Figure 1 shows a top plan view of my proved stoker, parts of the same being removed for the sake of clearness;

Fig. 2 shows an end elevation of the for'- ward end of the Stoker, parts of the 'same being removed.

Fig. 3 shows a side elevation of the Stoker;

Fig. 4 shows a loi'gitudinal sectionalview on the line 4-4 of .Fig 5 shows a partial transverse sectional View on the line 5-5 of Fig. 3; and

Fig. 6 show s a partial transverse sectional view on the line 6-6 of Fig. 3.

The mechanism of the stoker is su on a foundation 10 of concrete or t e like which is preferably arranged in a series of steps Y10, 10", and 10, A conduit 11 is provided between the foundation, pressure is supplied through this conduit to the underside of the grate, the flow of air being regulated by a valve 12. The Stoker comprises a .pair of side frames 14 which-are provided with upper and lower parts 14n, letb and 14, respectively, ada ted to rest upon the steps 10, 10b and 10c o the foundation. One or more intermediate center frames 15' are located between the side frames 14 and each center frame is provided with parts 155, 15b and 15c the parts A10, 10", and 10, respectively, of the foundation.

The side frames and the center frame carry the fuel feeding mechanism which comprises a plurality of under-feed retorts 16 which extend downwardly substantially throughout two-thirds of the'length of the grate and which are arranged in alternation with a plurality of endless flexible grate chains 17 Aextendin throughout the lenh of the grate. A p1 urality of other exile chains 18 are mounted between the .chains 17 from the lower ends-of the under-feed retorts 16 to the discharge end of the ate, and the lower portions of the chains 1 and the chains 18 have a lesser inclination to the horizontal than the fuel retorts and the upper parts of the chain 17, as shown particularly in Fig. 4. The lower ends of the side frames and the center frame have' their upper parts construtedto conform to the conthe two upper steps of and o, blast of air under which rest uponl ported i Too Vcranks 30a in opposite directions, so that one of thev formation of the upper surface of the grate. The inclination of the upper portion 'of the grate surface preferably approximates the angle of repose, but it is found in practice that an angle of about 20o is a suitable angle of inclination for most fuels, and the decreased inclination of the lower part of the grate surface is provided in order to effect a retardation of the fuel adjacent the lower end of the grate.

The fuel retorts 16 comprise metal troughs 20 whi^h are rectangular in crosssection` as shown in Fig. 5, and tapered toward their lower ends, so that the depth of each trough gradually decreases toward the lower end of the grate.- rlthese troughs are supported at their upper ends on a transverse -beam 21 which has its ends secured to the side frames 14 by means of angle plates 22. The -beam 21 is supported between its ends by one or more posts 23 which rest directly on the foundation 10a. The lower portions of the troughs 2() are supported by transverse -beams 24 which are secured to the upper side of the center frame 15 and to the inner walls of the side frames 14. the lower parts of the troughs being provided with downwardly extending portions 20a which are secured to the lower I-beam 25. The upper end of each trough is provided with a top wall 20b which Acooperates with the side walls and the lower wall of the trough to form a' guideway for a fuel pusher or ram 27. These pushers reciprocate in their guides to push the fuel downwardly onto the grate surface and they are operated by connecting rods 28 which are detachably connected through bearing blocks 29 with the cranks 30a of a crank shaft 30 journalled in bearings 31 carried by the troughs 2() and in bearings 32 carried by the side frames 14. The alternate of the crank shaft are directed pushers 27 is in its uppermost position when the next adjacent pistons are in their lower positions.

The crank shaft 30 extends through one of the side frames 14, and has its outer end journalled in a bearing 33 carried by an auxiliary frame 34 which is secured to the side frame. A gear 35 is secured to the shaft 30 between the'side frame and the bearing 33, and this gear is adapted to mesh with a pinion 36 secured to an intermediate shaft 37. The shaft 37 also has fixed thereon a gear 38 which meshes with a driving pinion 39 secured to the shaft 40 journalled in bearings cr-rre'l by the upper parts of the side frame and the auxiliary frame 34. The shaft 40 is'driven by a ratchet wheel 41 which is fixed fhereon and adapted to be engaged by a '.awl 42 pivoted on the bell crank 43 which has its other arm 43a connected to an operatinfr rod 44. The rod 44 may be reciprocated in their guides.

raeaaoo by any desired mechanism in order to effect the rotation of the ratchet wheel and the consequent rotation of the crank shaft 36 which causes the pushers 27 to reciprocate The fuel to be burned is fed to the grate from a hopper 45 which comprises an inclined lower wall 46 and a vertically movable feed gate 47 by which the size of the outlet opening 48 may be controlled. 'llhe furnace arch 49 of fire brick or the like extends upwardly and rearwardly from the feed gate 47, and the space between the lower wall 46 of the hopper and the foundation 10 is closed across the front end of the furnace by a front wall 5() of sheet metal, or the like, which may be provided with a plurality of openings to permit access therethrough to the operating mechanism of the Stoker. rlhe fuel which .passes through the outlet opening 48 drops into the retorts formel by thetroughs 20, and the pushers 27 engage the fuel and push it downwardly in the inclined troughs, so that it is gradually forced upwardly onto the fuel bed beneath theburning fuel. edges of the sidewalls of the troughs it passes thereover onto the chains 17, each of which is formed of a plurality of series 17a of alining links 51. The links in one series overlap those in the adjacent series, and connecting pins 52gextend transversely therethrough to form a pivotal connection between the links of the chain. Portions of the innermost links of each'chain are cut away on their inner sides, as shown at 53, to receive sprocket wheels adapted to engage the pivot pins or connected parts for advancing the endless grate chains and all of the links are provided with grooves in their sides to form apertures for permitting the flow of air to the fuel. The form of grate chain herein shown together with means to vary the tension thereof is more fully illustrated and described in my United States Patent No. 1,379,135 granted May 24, 1921.

At the upper end of the grate, the chains 17 are mounted on idler wheels 55 which are located between the fuel retort-s and adapted to rotate on the crank shaft 30 between fixed collars 56. At the lower end of the grate, the chains 17 extend around sprocket gears 58 which are secured to a drive shaft 60 extending transversely of the furnace and mounted in bearings 61 carried by the side frame and a bearing 62 carried by the lower portion of the center frame 15. The bearing 62 is open on its upper side and is provided with a slot 63 to permit the insertion of the shaft. rlhe chains 17 also pass over chain supportingl wheels 64 mounted on a shaft 65 which is supported by bearings 66 carried by the side frame and by a bearing 67 carriedby the center frame, the bearing 67 being open on its upper side to permit the As the fuel rises above the upper j rca insertion of the shaft. The shaft carries a plurality of other chain supporting wheels 69 which are located beneath the lower ends of the troughs 20 and the lower driving shaft 60 carries a-plurality of fixed sprocket ars 70 which are in alinement with the w eelsv 69. The short flexible chains 18 which extend from the fuel retorts to the lower end of the grate are mounted on the wheels 69 and sprocket gears 70 and are formed of complementary links which are connected together in the manner that the links of the chain 17 the lower end of the middle fuel retort which is located above the center frame l5 is preferably occupied by two chains 18 which are spaced apart, and the lower part 15d of the center frame extends upwardly between these chains with the upper surface thereof in alinement with thegrate surface formed by the upper surfaces ofthe links. The upper and lower stretches of the chains 17 and 18 are supported by tubular rollers 72 which are'adapted to rotate on rods 73 extending between the side frames and the center frame 15.4 These rods are detachably carried by the frame members and may be secured in position by nuts 74 or by other suitable means which will permit the ready removal of said rods. The upper stretches of the chain 17 are supported between the fuel retorts by dan es 75 which are formed integrally with t e lateral walls of the troughs and extend transversely thereto.

Both the chains 17 and the chains 18 are driven by the lower shaft 60, which has a worm-wheel 76 secured to the end thereof, and this worin wheel 77 which is secured to the lower end of a shaft 78 journalled in bearings 79 secured to the side frame 14. The shaft 78 extends upwardly to the forward end of the Stoker where it is journalled in a bracket 80 secured to the forward end of the side frame. A ratchet wheel 81 is secured to the shaft 78 between'the )arms of the bracket 80, and this ratchet wheel is adapted to be driven by a pawl 82 which is pivoted on one arm of a bell crank lever 83, the other arm of this lever being pivotally connected to an operating rod 84 which may be reciprocated by any desired mechanism in order' to operate the drive shaft 60 and thereb actuate the chains. In the operation of t e Stoker, the feed gate 47 ma be located in any desired position in or er to adjust the relative action of the under-feed mechanism and the dexible chains in advancing the fuel over the grate. When raised substantially above the grate surface, the gate 47 permits the coal to fall onto the chains as well as into the troughs, so that some fuel is carried downwardly onto the grate by the .advancing chains, and an additional quantity of fuel is fed onto the grate by the downward moveany n.,

are connected. The space belowis engaged by a wormy ments of the pushers 27. The positive feed of the chains is thus combined with the 4operation of the under-feed mechanism, so that a greater uniformity in the thickness of the entire fuel bed is maintained, 'while at the same time an adequate air supply is provided through the air spaces of the chains. The front wall 50 confines the air blast at the forward end of the stoker and a sheet metal partition is also preferably provided across the ends of the side frames beneath the lower end of the grate in order to separate the air chamber from the ash pit. The chains carry the fuel positively from the upper part of the grate to the ash pit, and the lesser inclination of the lower part of the grate operates to'retard the fuel and to effect a thickening of the fuel bed adjacent the bridge wall, so that the burning out of the fuel bed v without interfering with a positive discharge of the ash. lf the feed gate 47 be lowered until it rests directly on the upper parts of the fuel troughs, chains in conveying fuel directly from the fuel hopper is eliminated, and the fuel is fed to the I" te b the under-feed mechanism alone aer whlchthe chains cooperate with the pistons to advance the fuel downwardly throughout the grate surface. The action of the stoker can be regulated by adjusting the speed of the ratchet mechanism by which the chains are operated and by adjusting the ratchet mechanism by which the underfeed mechanism `is operated. If the chains run relatively slow there will be a greater accumulation of ash on the lower stretches of the chains, and the thickness of the fuel bed at the lower end of the grate will be increased. 'lhe use of one or more center frames 15 makes it possible to increase the width of the Stoker to any desired extent while at the same time providing the necessary support for the intermediate parts of the grate.

Although I have shown and described one embodiment of the invention for purposes of illustration, it will be understood that it may be constructed in various other forms without departing from the scope of the 'appended claims.

What I claim is:

1. rThe combination in a Stoker of spaced grate chains inclined downwardly at their forward portions, feeding troughs, pusher members coacting therewith, said trou hs being mounted between said spaced chains and having the sides thereof tapered to accord with the inclination of said chains, and substantially horizontal endless chains located at the extremity of each of said troughs between said first named chains adapted to retard the movement of the fuel at the forward end of the Stoker.

2. The combination in a Stoker of a pair trough, means of side frames, a fuel trough mounted hetween said side frames, endless rate chains mounted on opposite sides o said fuel trough, a crank shaft journalled in said side frames, a pusher mounted in said fuel for operatively connectin said pusher with said crank shaft, a secon shaft mounted parallel to said crank shaft, a series of sprocket gears fixed on said second shaft, a lurality of chain supporting Wheels rotata ly mounted on said crank shaft, said grate chains being mounted on said sprocket gears, and said chain supporting wheels, and means for of said shafts.

3. rlhe combination in a stoker of a pair of'side frames, a fuel trough mounted hetween said side frames and extending through a portion of the length of the grate, an endless grate chain extending in alinement with said fuel trough through the reactuating each receso@ maining portion of the length of the grate, a shaft journalled in saidside frames adjacent the feeding end of the grate, means actuated by said shaft for advancing fuel in said trough, a second shaft journalled in said side frames adjacent the lower end of said trough, a third shaft journalled in said frames adjacent the lower end thereof, wheels mounted on said second shaft and sprocket gears on said third shaft for supporting said endless grate chain, other wheels mounted on said first-named shaft and other sprocket gears on said third shaft, other grate chains extending throughout the length of the grate on opposite sides of said fuel trough and supported by said other wheels and sprocket gears, and means for driving said third shaft.

ln testimony whereof, l have subscribed my name'.

LQYD R. STOWE.

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