US1689202A - Furnace stoker - Google Patents

Description

0d; 30, 1928. Y I 1,689,202

w; A. HARE FURNACE STOKER Filed Nov. 23. 1922 2 Sheets-She et- 1 awoo wiioz Oct. 30, 1928..

w. A. HARE FURNACE STOKER 2 Sheets-Sheet Filed Nov. 23. 1922 I awoentoz reams oct'eio, eae.

wrnrann A. HARE, or nn'rnorr, r'aicmeam' summon s'ronn'n.

Application aiea now-renter 2a, 1922. serial no. states.

In applying an automatic stoking device to domestic or small fuignaces, dificulty arises;

H due to the limitedspa ce within-which such-12 litdevicemust be installed in order ton1ake the' 1 same universally" applicable to flllfniaces of this character now on the market and an lobject of the invention is to provide a, stokerwhich may be readily applied to and installed inthe several common forms of house-heating or domestic furnaces and the like. Further,

in the application of an automatic stokerto operation is essential to commercial success,.

-' and therefore, the device should be so structed as to require only a minimumamount of power for operating the fuel feeding and ash eliminating mechanisms, and it is therefore an object of the present invention to so construct these mechanisms as to secure ease of operation and prevent cloggin whereby a small motor may be employed wit assurance of continued and efficient opera-v tion, A further object is to provide .simple and eflicient means for intermittently feeding at regular intervals, measured uantities of fuel. to the fire pot or combustion chamber,

and means for supplying air to maintain combustion, all combined in a Structure adapted tobe applied as a unit to a domestic furnace. 5

It is also an object, in such application, to provide a stoking devicerequ ring a minimum of attention and which is simple in .con-struction and efficient in operation, and wherein are embodied other new and useful features, further and efiiciency. I With the above and other ends in view, the invention consists in the matters'hereinafter set forth and more .particularlypointed out in the appended claims, reference being ha d to the accompanying drawings in which Figure 1 is aside elevation of a stok ng device illustrative of the'inventiom'with portions broken away and in section to more clearly disclose the construction and showing the device as applied to a furnace structure;

'Fi 2 a longitudinal vertical sectionsub- 'stant ally upon the line 2-2 of Big. 3;

Fig. 3.;is ajhorizontal section, the portion a i being a sectionsubstantially upon the line increasing its reliability I of,said..figure belowthe line 2-2 thereof,

3 3 of Fig. 2 and that portionabove said i line, being a section substantially upon the l1ne 44; of Fig. 2; J Flg. 4 is a sectional detailof the fuel-hopper discharge and measuring mechanism,

showing the latter in discharge position to 7 illustrate its operation and upon the line 5-5 of Fig. 1.1

Fig. 5 is a sectional detail isiibstantially =65. For the purpose of illustrating an application of the invention to a common form of 1 furnace, the lower end portion of a conventinal form'o'f furnaceis shown, 1 indicating the. combustion chamber, surrounded by con-' centric spaced walls 2 forming betweenthem u a 'water space or annular-water leg 3, and 4 small furnaces or heating plants, economical I removed and a front casting or plate 6 su sti:

tuted therefor or the usual plate when of suitable construction may be employed, said front or plate being provided with an opening to receive a suitable casting 7 forminga section of a suitable fuel delivery-trough or passage, such trough section being inserted through the usual draft door opening when the usual furnace front is utilized, and below the opening in the furnace front in which this casting is inserted, is a; doorway closed by an ash door 8 (hi 2) and through which doorway the ash an cinders may be removed from the ash pit. 4 p

Bolted or otherwise secured to the outer end of the casting 7 and to the front platefi, v is a suitable casing indicated as a whole by the numeral 9 and this casing is formed with a continuation of the fuel trough or passage 10 and the outer end of this trough communi-i cates with the fuel measuring device located within the casing and hereinafter described, said measuring device being located to receive fuel from a suitable hopper 11 mounted upon the casing. The casing also fo rmsa housing for driving mechanism'for driving a screw conveyor 12 located'in and extending longi tudinally of, the fueltrough 10, said drive mechanism com-prising a worm 13 secured upon the armature shaft 14 of an electric ios motor 15 and engaging a worm wheel 16- Y which worm wheel is secured upon a shaft 17 which is an extens on of the screw conveyor 1'12, and also a housing for a worm 18 on the shaft fl'7 and a, worm wheel 19 on a shaft 20 extending at rightangle's to and below the shaft 17, and further for bevel gears 21 and 22, the gear 21 being secured upon the shaft and the gear 22 upon the end 'of a shaft 23 which extends through the rear side of the housing parallel with the conveyor screw, and which shaft conveys motion from the shaft 20 for driving underfeed mechanism, hereinafter described, the worm gears 18 and 19 and the bevel gears 21 and 22 being located upon their shafts within a suitable chamber at its inner end and is detachably connected gear 31 20. The drum isthus turne tion to the movements of the other parts, to

at its outer end to the end of the shaft 17 in any suitable manner, as by providing an internally serewthreadcd socket 27 on the outer end 'of the eonveyor' shaft to be engaged by the screwthreaded end of the shaft 17. The free or unsupported end of this conveyor extends within its trough to a point adjacent the underfeed mechanism to deliverfuel thereto from the measuring device which is located at the outer end of and above the trough 10, and comprises a rotary drum 28 having diametrically opposite openings or slots in the sides thereof, one to register with the discharge throat 29 of the hopper 11 in one position of the drum, and the other to. register with the inlet to the trough 10 in another position of the drum. 3 This drum is rotatable upon projecting end trunnions 3.0, upon one of which is secured a segmental to mesh with a like segment 32 secured u on a rock-shaft 33 which shaft is mounte to rock in bearings on the frame or easing. Motion is imparted to this rock shaft 33 from the shaft 20 below,by means of a crank arm 34 on the shaft 33, to the free end of which arm is pivotally attached a connecting rod 35 having pivotal connection at its lower end with the, free end of a crank arm 36 indicated in dotted lines in Fi 2, on the shaft in timed relabring its inlet opening into registry with the hopper throat 29, as shown in Fig. 2, and

to bring its discharge opening into registry with the inlet end of the trough 10 as shown in Fig. 4. 5

In order to feed the fuel from the hopper 11 into the throat 29 and prevent clogging, a

. feed slide 37 is rcciprocable across the lower or discharge end of the hopper, in a suitable guide 38, and a flap or plate-39 is pivotally attached at 40 near one edge, to the lower end portion of the slide, the opposite end of said flap being thickened and rounded as at 41 to rest bygravity and slide upon the top of the measuring drum 28, the reciprocation of the slide and flap carried thereby being so timed relative to the turning movement of,

the drum, that the flap will bewithdrawn from over the-opening in the drum as said opening moves into registry with the hopper throat and will be projected over the .drum as the same is turned toward discharge position so that clogging of the feed in the throat is prevented by the flap and interference with the cut-off movement of the drum obvi-.

ated.

To reciprocate the feed slide 37 and flap carried thereby, said slide is provided with a series of teeth 42 to be engaged by a-mutilated gear or segment 43 on the rock shaft and therefore said slide and flap are reciprocated in timed relation to the turning movement of the measuring drum 28. To form a yieldable seat andclosure for the lower side of the "drum, a 'shoe or plate 44 having an inner surface curved to conform to the curvature of the outer surface of the drum is provided, and this shoe is pivotally supported at its outer edge, as at 45 to swing upon said pivot into firm contact with-the drum and close the discharge outlet from the drum when its inlet openin is in registry with the hopper throat. This sioe is normally held in contact with the drum by means of a weight arm 46 extending outwardly from the pivot 45 of said shoe, and therefore clogging or binding of the drum by reason of particles of fuel getting in. between the drum and. its closure or seat is prevented, as the shoe may swing away from the drum against the action of its weight-arm and relieve the binding action of any such obstruction, and further, any sifting of fine particles of fuel through the joint or seat is normally prevented as the shoe is firmly held in contact with the drum by the action of the weight arm. The flap or 5 plate 39 reciprocating over the inlet mouth of the drum and across the hopper throat 29,

supports the weight of fuel in the hopper and prevents jamming of the fuel in the throat against the drum, thus permitting freer moyement of the drum and requiring less lUO power to operate the drum and other fuel feeding members. With this arrangement clogging of any of the fuel. feeding mechanismis obviated and eflicient operation insured.

Ease of operation and consequent minimum power requirements is further insured by the arrangement of the conveyor screw 12 and its driving mechanism in that said screw is continuously driven by the worm 18 and worm gear 19 whilefmeasured quantities of fuel are intermittently fed to the screw, and therefore a measured quantity of fuel fed into the trough 10- is. quickly conveyed to the v nseam;

underfeed mechanism, hereinafter described,

before another chargev is delivered to the conveyor, and ease, of operation and minimum power requirements are insured as thescrew conveyor is never overloaded or buried .in fuel' and may be rotated at a comparatively high speed.

-'Reciprocable msultable ways across the I lower or discharge end ofthe hopper 11 and directly above the feed slide 37, is a manually operablejcut-o'fi "slide or plate which may be moved in'or out by the operator to regulate co 1 inuation 48 of the through 10,,said exten si'on leading radially inward to one side of a circular seat 49 for a circular fire put 50 which extends downwardly withim the casing 47 at the axis thereof and has an'openlower end andan inner surface which converges downwardly and is formed with a seriesof steps or ledges 51, each of greaterdiameter than the one below. This fire pot is arranged to fit loosely within its seat 49 in the casing 47 and is removably supported therein by means of an outwardly extending annular flange 52 on itsupper end resting upon the top of said casing. g Y

The mechanism for feeding fuel upwardly into the open lower end of the fire: pot whichfuel is delivered thereto by; the screw coneyor inthe trough 10 and its extension 48. comprises a cylinder 53 pivotally supported at its lower end, as indicated at 54in dotted lines 'n'Fig. 2, in-the casing 46" directly heneath he open lower end of the pot, and arranged to swing from the'inclined position shown in said figure with its open upperend in position to receive fuel from the inner end of the feed trough, into vertical alignment with said open lower end of the pot. This cylinder is formed with laterally extending wings 55 which are curved concentrically with the axis of pivoted support of said cylinder and the'wall 56 of the casing 47, in.

which wall an opening is formed registering with the open ends of the troughand fire pot, is "also curved concentrically with said axis,

. so that .these vidngs form .a closure for said opening in all positions'of the cylinder to prevent the escape of fuel into .the casing 46 and to support the fuel .in the pot-when thecylinder is turned out of alignment there? with. I Y

The cylinder 53' is also open at itslowem forms a closure for this lower end and also a plunger to force the fuel out'of the open upper end and upwardly into the fire pot when the cylinder, filled with fuel, is turned to a vertical position. a

- To swing the feed cylinder. upon its pivcomprises a shaft 58 (Fig. 1) extending transversely of a lateral extension 59 of the casing46 and within said extension is a cani member 60 secured upon the'shaft 23, said .oted support, the support at one side thereof cam being provided'with a camroove 61 engaged by a pin or roller 62 on t e end .of

an arm 63 secured upon the outer end ofsaid shaft 58. The cylinder is'thus swung between-receiving and discharge positions in timed relation to the feeding of measured J quantities of fuel and said cam groove is preferably so formed as to effect a quick swinging movement and a dwell or station? ary period at both its receiving (asshown in Fig. 2) and its" discharge. or vertical position. a

The reciprocation of the piston or plunger 57 is'also effected in timed relation" to the swinging movements of the cylinder and the operationof the feeding mechanism, by providing a second cam groove 64 in the cam member (SOengaged bya roller 65 on'the. free end of an arm 66 which is secured upon the outer end of a .shaft 67 extending parallel with the shaft 58, which shaft 67 is provided with a second arm 68 (Fig. 2) adjacent itsv inner end extending beneath the open lower end of the cylinder and having its free end pivotally' connected tothe piston 57 by means of a link or'connecting'rod 69. The cam groove 64 is preferably so formed as to cause the'piston to recede rapidly to the lower end of its stroke after the cylinder has reached its receiving position'as shown in Fig. 7, and to remain in that positionuntil said cylinder has been swung to discharge or vertical posi-' tion whenfurther turning of the cam will efiect a slow upward movement of the piston 11" which will gradually force the charge'of fuel in the cylinder upwardly into the bottom'of the fire pot, pushing the previously fed fuel upwardly in the pot. 'When the piston has reached the upwardor discharge end of its charge .to receiving position, and as the upper "end face ofthe piston is curved to conform to the curvature of the wings, the fuel'is en-' tirely ejected from the cylinder an'd'this'end of the piston substantially. fills the end of the cylinder, providing a comparatively smooth surface-together with said wings,',t0. support the fuel inthe" fire-pot and permit the easy swinging of the cylinder 'therebeneath, the

end, but a piston 57 reciprocable therein slight retraction of the piston relieving the g 113' stroke with its upper end face flush with the pressure thereon When the cylinder is in *lower end 0 charged from the drum into the-outer end of the conveyor trough just about the time said cylinder reaches its receiving position so that the charge will be quickly conveyed by the continuously rotating conveyor screw, to the open upper end of the cylinder to fill the same. a As previously described, the fire pot 50 is of inverted truncated conical shape, that is, flared upwardly and outwardly with its'bottom opening of smallest diameter and its inner surface formed with the series of steps 'or ledges 51 so that as the fuel isforced upwardly therein by the piston 57 it will grad-.7 ually spread out,

riphery upon the several ledges and bridging across the pot so that the weight of fuel above will be supported by this bridging ac tion of the fuel itself and the gradual upward enlargement of the pot will permit the free upward movement of the fueltherein without clogging.

Aseries of twyer rings 70 forms an upward extension of the fire pot 50, said rings being superposed loosely, one upon another and the bottom ring being formed with an end rib 71 to fit over an'annular rib on the pot and hold said rings in position relative to the pot. Each ring of the series is of greater diameter than the next ring below and the intermediate rings are'formed with downwardly extendin ribs 7 2 upon their under sides to rest upon tide ring below and form spacers for the rings and also a plurality of radial air pas sages between the rings for the entrance of air to maintain combustion within the twyer formed by the rings which twyer is an upward extension of the fire pot. Downwardly extending lugs or portions 73 or each rib .7 2 on eachring above the bottom ring, engage over the ring below )0 center the rings and de tachably hold them in place, one upon another, and an annular enclosing wall74 of a diameter equal to the diameter. of the casing 47 below, is bolted or otherwise secured to the top of said casing and is formed with a rounded and inturned upper edge flange 75 extend ing inwardly and over the upper ring of the series. A series of spaced vertically and inlower side and wardly extendingribs 76 is provided upon the inner surface of the wall 74, these ribs also extending inwardly of the flange 7 5V on the to the inner edge thereof to twyer ring and form air engage the upper rough the twyer into its passages opening th the bulk resting at its peinterior or the combustion chamber formed thereby. An annular upwardly extending and outwardly'fiaring wall member 77 is'also.

secured to the top of the casing 47 with its lower end encircling'the supporting flange 52 47 through the annular opening 78 in thetop of said casing, to pass upwardly around said wall and over the upper edge thereof before it can pass through the-air passages formed by the ribs 72 and into-the fuel to maintain combustion thereof within the combustion '70 of the fire pottoassist in holding the pot, in place and with its upper edge spacedf-rom the air entering said chamber from'thea casing chamber. 'The ribs 76 in the wall 74 tend to distribute the air flow around the twyer and to direct these air streams into. the air ducts between the ribs on the twyer rings, and

as the annular wall 77 is spaced from'the twyer rings,the air may flow downwardly'in 4 the space bet-\veen'it and the lower ring to coolthis ring and to supply air to the'twyer ducts between this lower'ring and the next rin above. Y i

s the fire pot 50 and twyer rings are simply set in place in interlocking relation and firmly secured in position by the enclosing wall 7 4, the inwardly extendingflange 75 of which engages over the upper ring of the series, the entire twyer and fire pot may be quickly and easily removed by simply dis-' connectin the wall member 7 4 from the oils ing 4,7, w en the several parts may be lifted out. Further the construction of the twyer such that air for maintaining combustion is supplied evenly through the air passages in the twyer at all points of the twyer surrounding the combustion chamber, and as each twyer rlng is inclined inwardly and downwardly in cross section, as shown-in Fi 2, the

air ducts formed between the ribs 2 will also be inclined inwardly and downwardly toward the combustion chamber so that fuel fed'upwardly from the open lower end of the fire pot will not get into and clog these ducts. Further, it will be noted that each succeeding twyer ring is of greater internal diameter than the ring below, thus providing a series of steps or ledges at the inner faceof the er formed by these rings, which steps or. I

t l ges form peripheral supportsfor the body of fuel which bridges the combustion cham ber wlthmthe twyer and thus prevents packmg and consequent clogging of the fuel --in' the combustion-chamber. The upwardly and outwardly inclined wall formed by the twyer rings'also assists in the pushing'of the coal upwardly within the combustion chamber from beneath, because of the gradual expansion'of'the mass within the chambera's it is moved .upward'and finally flowsover the pefuel in the combustion chamber but that por h= tion of the fuel which passes over the periph eral edge of the chamber is caught by the-annular grate 79 which surrounds the enclosing wall 74 and is burned there-0n, combustion being maintained by air from the ashpit 4 which passes upward past the grate through the narrow space between the inner edge of said grate and said wall and between the outer edge of the grate and the surrounding wall 2 of the furnace. 4

This grate 79 com rises an annular casting having an imper orate upper coal carrying surface Which is inclined radially outward and downward and also inclined in the direction of its length, being of spiral formation with the high end and the low end of the spiral surface 80 connected by a vertical portion-81, and, as shown in Fig. 2, this grate is supported upon one or more rolls 82 pivotally mounted upon the outer side of the wall 74 and also by a lever 83 pivoted intermediate its ends, at 84, to the wall of the easing 47 with its upper end loosely engaged between downwardly extending ribs 85 on the grate. To the lower end of this lever 83 is pivotally attached one end of a connecting rod 86, the opposite end being pivot-ally attached to a disk or wheel 87 secured upon the end of the shaft 23 which serves to transmit motion from the shaft 20 and prime moving mechanism previously described. An 0scillatory motion is thus imparted to the grate to cause the ash and clinker and residue of coal falling upon the grate over the upper edge of the twyer to travel down the spiral surface of the grate and radially outward to ward the surrounding furnace wall 2. The lower end portion of the spiral grate surface is preferably curved downwardly as at 88 to assist the discharge of any large clinker into the'ash pit, the finer particles of clinker and the'ash being discharged into the ash pit through the narrow space between the outer edge of the grate and the wall 2 during the .travel of the residue down the spiral. .As

' the wall 2 presents a smooth surface into contact with whichclinker comes"durin'g its travel down the incline of the grate, andas the grate surface is. also smooth, clogging or ment of the grate, is obviated and unburned portions of coal remain upon the grate until consumed.

,To provide air under pressure for mainer or motor 15 for driving the underfeed stok binding which would prevent the free movetaining combustion, a fan oi blower 89- (-Fig.-

thereby and by the front plate 6, said fan casinghaving an axial air inlet-opening 91' and a tangentoutlet throat 92 which is connectedto theouter end of an air passage 93 formed at one side of the-casting 7 parallel 7 with the trough 10 and opens into the casing 47 which surrounds the fire pot and has the annularopening 78 in its top for the upward escape of the air into the chamber enclosed by-the wall 74 and surrounding the twyer. 7 A constant supply of air under pressure is thus provided for maintaining combustion 7 within the combustion chamber and by providing an opening 94 in the passage 93 a portion of this air may be passed into the ash pit 0 4: to n'laintain combustion uponthe grate 7 9, said openinglbeing provided with a cover or closure 95 for opening or closing the opening to the desired degree so that the amount of air which is permitted to escape into the ash s5 pit may be regulated. By the described construction, a verycompact arrangement is secured embodying all of the elements necessary for efliciently and automatically feeding fuel and maintain ng I .combustlon, whlch construction 1s particular- 1y applicable to domestic or house'furnaces, being a unit construction and of a size and form to be readily inserted in theash pitof the several forms of furnaces as usually 1 constructed. The construction also insures eificient and. uninterrupted operation at a minimum expense due to low power requirements,- and as the fuel-feeding mechanism and fanfor supplying air to maintain oombustion are driven-by a single motor mounted upon the casing andidirectly connected to said mechanism and fa the proper relative k proportion of air and fuel is always maintained. Further, the construction and ar- 5 range'mentis such that the device may be -made entirely automatic by providing a -thermostatic regulatingdevice (not shown) for stoppingfandstarting the motor so that the fire will be constantly maintained at a rate 1 to maintain the desired house temperature without any attention on the partofthe occupant further than to keep fuel in the hopper.

Ob iously changes maybe made within the scope of the a pendedclaims, in the articular form an arrangement describe with-- out; departing from the spirit of the invention, and I do not, therefore, limit myself to the construction shown. U

Having thus fully described my invention, what I claim is 1. In a device ofthe character described, the combination with a; hopper having a discharge throat, a casingbeneath said hopper, a measuring device mounted for turning movement in said ca'sing and having an inlet open- .ing to receive fuel from said throat and adischarge opening, a; trough member to the outer end of which said casing is attached, l

said trough member being positioned with its outer, end in position to receive fuel discharged from said measuring device, a conveyor in said trough for conveying fuel dis charged thereinto by the measuring device, means for o erating the conveyor, means for rocking sai measuringdevice about its axis,

a-plate adapted to project beneath the-hoppcr throat and over the measuring device, and means for operating said plate in timed relation to the. rocking movement of said measurng device.

2 In a device of the character described,

- the combination of a fuel hopper having a dismeans for operating said'conveyoiy 3. A device as characterized in claim 2 and wherein a plate is pivotally connected adjacent one, edgeto the free end portion of said slide, said plate being free to engage and ride upon the top of said drum adjacent its free edge;

4. A devlce as characterized in claim 2 and including a manually. operable regulating slide for regulating the discharge of fuel from the hopper, said regulating slide being reoiprocable across the hopper throat adjacent to and directly above the feed slide.

5. In adevice of the character described,

the combination of a supporting casing and an extension therefor adapted to be inserted within an opening in a furace front with the casing projecting outside .the furnace, said casing and extension being formed with a passage for fuel to be fed therethrough to the combustion chamber of the furnace and with an air passage at one side thereof for supplying air to maintain combustion in the combustion chamber, and with an air chamber below the furnace iii-e pot into which said air passage opens, said air chamber being open-at its top to discharge air upwardly around the fire .pot, said supporting casing being also formed with a fan chamber communicating with the outer end of said air passage and also forward with a gear chamber, a conveyor in said fuel passage, a fan in said fan chamber, a hopper mounted upon the supporting casing and having a discharge throat communicating with the outer end of said fuel passage,

a motor mounted upon said supporting casing, a. motor shaft upon which said fan is mounted, and .gearing within the gear chant ber of the supporting casing for transmitting motion from said motor shaft to operate said conveyor.

6. A device as characterized in claim 5 and including a fuel measuring device mounted in said supporting casing between the outer end of the fuel passage and the hopper throat, and meansoperated by said gearing for actuating said measuring device.

7. A device as characterized in claim 5 and including a hollow measuring drum mounted in bearingsv on said supporting casing and having an inlet opening at one side to receive fuel from the hopper throat and a discharge opening at .its opposite side for the discharge of measured quantities of fuel into the outer.

end of said fuel passage, a feed slide reciprocable in ways on the supporting casing across the hopper throat above said measuring drum, and means operated by said gearing for turning said drum on its axis, and reciprocating said feed slide in timed relation to' the turning movement of said drum. v

In testimony whereof I aflix my signature.

WILFRED A', HARE.

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