US1729776A - Furnace - Google Patents

Description

Oct. 1, 1929;

W'. 'A. HARE FURNAGE Filed Feb.' 8, 1926 5 Sheets-Sheet Oct. 1929. w, A, HARE 1,729,776

FURNGE I Filed Feb. B, 192e s sheets-sheet 2 @Ww/whoa Ot.1,1929. wA-,HARE 1,729,7*16

4FURNAGE Filed Feb. 8, 1926 5 Sheets-SheetA 5 lf: l Q 91 s im g; l I I x @l O3 k) l u i Rv y N I C Q l q 7 i Q "u H 1f atroz neg V, Patented Oct. 1, 1929 PATENT OF FICE `VTQIIiFBE'IID A. HABE, 0F DETROIT, MICHIGAN FBNACE Application led February This invention relates to furnaces of the automatic stoker classvand more particularly to automatic stokers use. An object of the invention is to provide a movable grate structure for the automatic elimination of ash and clinker which structure is applicable todomestic furnaces, particularly those of the round firev pot type. A furtherobject is to provide such a great structure which is applicable to stokers of the under-feed type, and an arrangement whereby the feeding of fuel and the operationof the grate structure is effected in a simple and efficient manner. It is also an object to provide an automatic Stoker of simple construction/which may be readilyapplied to common types of domestic furnaces, and embodying a construction wherein the parts may be `readily assembled and as readily disassembled for the purpose of replacement or repair. A further object is to provide in a stoker for the purpose and of the present type, a simple construction and arrangement for supplying air under pressure to the grate surface and retort for the purpose of maintaining combustion, and to provide certain other new and useful features in the construction and arrangement, whereby compactness and appli- @ability are secured and cost of manufacture is reduced.

Withthe above and other ends in view, the invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims, reference being had to the accompanying drawing in which- Figure 1 is a transverse vertical 'section through a structure illustrative of an embodiment of the present invention; l Fig. 2 is a side elevation of the structure shown in Fig. 1;

Fig. 3 is a plan view of the structure vshown in Fig. 1 with portions broken away and in section to more clearlydisclose the construction; Fig. 4

structure Fig. 3;

Fig. 5 is a perspective View of a pair of grate bars; and

is a transverse vertical section ofthe substantially' upon the line 4-4 of designed for domestic- 8, 1926. Serial No. 86,786.

Fig. 6 is a transverse section of a plurality of bars in operative position.

lIn the drawings and as illustrated in Fig. 3, Aindlcates the base of any old and well known construction of domestic furnace upon which upper structure B forming the fire chamber of the furnace is supported in theusual manner. Within this base is supported a wind boxl of circular formation in plan View, 'having a neck portion 2 extending through a door or\ other opening, in a side wall of the box A and through which neck portiony air 1s supplied under pressure in any suitable manner, to the box. Arranged axially with- 1n the box 1 is a vertically extending fuel chamber 3 open at its upper end and supported by an axial gear chamber 4, the upper wall of which closes the lower end of the fuel chamber, and leading laterally from the fuel chamber 3 is a tubular fuel passage which I extendsoutwardly within the neck portion 2 of the wind box to a point outside the fur- 'naple to receive fuel at its outer end, as from a opper or other holder, not shown, and within this tubular passage is a screw conveyor 6 for conveying the fuel inwardly to the fuel chamber 3 and to a vertically arranged screw conveyor 7 within said chamber. Secured directly upon the'upper end of the chamber 3 is a retort comprising a tubular upwardly and outwardly flaring magazine 8 into the -lower end :of which fuel is forced by the screw 7 and a twyer or cap ring 9 which is supported upon the upper end of the magazine and forms' an upward extension of the l86 magazine and rounded upper end or throat therefor, said magazine and twyer ring thus t together forming a retort or circular fire pot which is supported axially of and ext ends upwardly for a short distance within the lower end ofthe fire chamber of the furnace.

The twyer ring 9 is formed with an inwardly and downwardlyv extending flange 9", the upperv surface of which forms a continuationof the outwardly Haring curved inner surface of the magazine 8 and the under surface' of `this flange is formed with ribs 9b to rest upon an outwardly curved fiange 10 von the upper end of the magazine 8 and space the twyer ring from the flange 10, thus providing air entrance openings 11 opening into the upper part of the retort with said ribs forming between them and between the twyer ring and flange 10, air passages which are in communication at their outer ends beyond the -outer edge of the flange, with the air box 1 to receive air under pressure therefrom. Certain of said ribs 9b are formed with downv wardly extending portions 9c toengage the from the under side of the ring and spaced .the outer ends of the air from the peripheryof the flange 10 to direct the upwardly flowing air under pressure into passages formed by the ribs 9b. vThis annular rib 9 also serves to divide the air stream and deflect a part thereof outwardly beneath the outer annular edge of the ring 9 and through a small space 12 between said edge and the inner ends of a series of' radially extending grate bars 13 surrounding the twyer ring and extending outwardly therefrom, to supply a small l' amount of air underpressure to the upper or inner edge of said grate along the entire outer edge of the ring and maintain combustion along said edge,

The several grate bars 13 are supported at i their inner ends upon the upper edge of a movable ring 14 for imparting thereto al movement'for working the fuel flowing over the -twyer ring'from the retort or fire pot, outwardly along said lbars and to cause,- the ash and clinker to pass from the outer ends of these bars and fall into the ash pit formed by thebase A. To connect these several grate bars 13 to the ring 14 at their inner ends `so I rthat they will becaused to move therewith,

each bar 13 is formed with a notch 15 at its innerend to receive the upper edge ofthev ring 14. All of the grate bars are" thus detachably attached'to the movable or grate bar actuating ring 14 to move therewith, said bars resting at their outer ends upon a rotatabld supporting or ash ring 16 having a broad flat upper Surface upon which the bars may rest and slide freely when motion is imparted y thereto by the ring 14. This ash ring- 16 is extended voutwardly beyond the upper flat surface upon which the bars rest and is preferably formed with a series of annular `steps 17-extending outwardly and downwardly be- A yond the upper bar supporting surface of the r1ng to receive the ash and clinker discharged from the ends ofy said bars, and this ash orl grate bar supporting ring is rotated upon a gear at diametrically opposite points. This ring gear member Vrests with its lower edge riding upon the rollers with the ash ring may be freely rotate and to impart an intermittent rotative movement thereto, said ring gear is formed with ratchet teeth 24 on the under side of an outwardly extending annular flange 25 on said ring gear, said ratchet being engaged by a pawl 26 pivoted intermediate its ends upon one end of a lever 27 having a pivoted support intermediate its ends upon a bracket 28 secured* the outer side of the windbox wall, the loweend of said lever 27 being connected by a link 29 to a crank disk 30 on the outer end of a drive shaft 31 which shaft extends through the wall of the wind boxand across the same, and into the gear box 4. Rotation of sha-ft 31 therefore swin s the lever 27 upon its sup'- port, through t 'e crank and link connection, and as the pawl 26 is carried by the upper end of this lever, it will' engage the ratchetteeth 24 during one movement of said lever, and rotate the ring' gear in one direction, and

Avduring the other swinging movement of said thereof will hold its opposite end in engagement with the ratchet teeth and to support the tail end of said pawl, a roller 32 is mounted upon the bracket 28'. The tail end of the pawl rides freely upon the roller and the roller prevents the pawl from exerting an upward thrust on the ratchet ring, which thrust might otherwise tend to lift the ring gear olf the su porting rollers 18, which rollers are provi ed with -flanges 18a to engage and center the ring gear concentric with the axis of the retort `8. x

As the ring gear 20 is in constant engagement with the piions 22, these pinions are to impart extending studs or pins' (projecting radially from the i box 1, said ring 16 being rig- 18 so that it, together v .diate its ends, the weight Aof the tail end l of the several radial grate bars 13 are con- 'l nected so that said said ring 14` is provided at diametrically opposite sides, with outwardly extending arms 33 which are formed integral with or rigidly vattached at their inner ends to'said ring 14, and at their outer ends are provided,

eachy with an eye forming a bearing to receive a pin 34 on each pinion extending 'upwardly gratel bars will be moved,

from the side Athereof and positioned laterally of the axis of turning movement of the said pinions to form crank pins for transmitting motion from said pinions to the ring 14. As said pinions 22 are positioned at diametrically opposite sides of the ring member 14 and as the arms 33 are rigidly connected to said ring, the motion of travel of the crank pins about the axes of the pinions, is directly imparted to the ring 14, thus imparting to all of the radial grate bars a motion defined by the travel of the crank pins during each vrotation of the two pinions, the outer endsfof the bars sliding upon the upper flat surface of. 'the ash ring 16, and moving at their .inner ends with the actuating ring 14, which ring' slides freely upon the flat upper surface of an annular flange on the upper end of the wall .of the wind box 1.

Power for rotating the grate supporting ring 16 through the medium of the pawl 26 and ratchet 24 and for imparting movement' to the several grate bars through the medium Y of the ring 14, is transmitted from any suit- The several grate bars 13, as shown inA Fig.v

3, are tapered throughout their length and are of, greater width at their outer than at their inner ends so that when. placed side by side in'radially extending position about the retort, they will fit closely together and form,

ineflect, a continuous annular. grate ,spanning the space between the operating ring 14, and the.ash ring .16, with the inner ends of the bars lying beneath the outer edge of the twyer ring 9 but free to move relative thereto, and substantially filling the space between the upper end of the grate bar operating ring 14 and said edge of said twyer ring, there being only sufficient space 12 between the upper face of the ends ofthe bars and the edge of the twyer ring to permit a small `amount of air under pressure to escape from the wind box and maintain combustion upon the upper ends of the grate bars, which space is always kept clear by themovement of the bars relative to this cap ring of thetwyer.

'krlo prevent too rapid a discharge of ash and clinker from the lower or outer ends of the. grate bars and from the ash ring 16, a filler ring member 42 iinserted between the upper end of the base A and the lower end of the structure B, said ring being formed with an inwardly extending annular flange 43, of an innery diameter to provide a narrow space between theouter ends-of the grate bars and said flange, with the flange projecting inwardly over the stepped portion `17 of the ash ring 16. This filler ning also serves as an adapter to permit of the adapting. of

what inrdiameter and also to vary the height of the base, ring adapters or filler rings of different sizes in diameter and cross-sectionl being provided to take care of such variations. j

As before stated, air under pressure issupplied to the wind box Land a portion of this air is admitted to the retort or fire pot through the passages formed between the ribs 9* on the twyer ring 9 as described. Forced draft or a portion of this air under pressure also escapes through the annular space at the outer edge of the twyer ring to maintain combustion on the upper ends ofthe grate bars, and` to provide forced draft for maintaining com-y bustion upon the surface of the annularv grate formed by the several grate bars 13, each bar is formed with a recessed side to co-operate with a'like 'recessed side of an adjacent bar in forming a passage 44 open at the inner ends of the bars to receivey air under pressure from the wind box and this passage opens into the base A to furnaces 'which may vary some- ..10 i

the inner lendI of a chamber 45 formedA by recessingadjacent sides of adjacent bars so that one-half of each chamber will be in one bar and the other half in the other bar. Vhen the bars' are placed side by side in close contact, a closed chamber is formed extending throughout the main portion of the length of said bars and is open through the outer end or the end face which rests upon the ash ring 16 so that the outer ends of said chambers will be closed by said ring. The edge of the bottom wall 46 ofthe recess in one bar fits closely againstthe like wall. of the recess inthe adjacent bar, tightly-closing' the lower side of each chamber 45 but the upper walls of these recesses, the outer surface of which forms the uppei` grate surface, are formed to 'provide narrow longitudinal 4slots 47 openf ing through the` grate surface and providing for the escape'of air from-the chambers 45',

upwardly through'the grate surface to maintain combustion thereon throughout the.

length thereof.. A rib 48 on each bar co7 operates with a like rib on an adjacent bar to form a division baille betweenthe inner end of' each chamber 45 and passage 44 leading thereto, this baille extendlng downwardly from the upper wall of the chamber to near the bottom wall 46 thereof, so that air under pressure will enter the upper or inner end of each chamber near the bottom thereof to blow any-ash which may fall into the chamber through the slot' 47, along the bottom toward the lower or outer end ofthe chamber, which end is closed by the ash ring. The grate bars are all so shaped as to provide an outwardly and downwardly inclined grate lsurface to assist in the discharge ofiash and-clinker from their outer ends onto the ash 'ring and also to incline the chambers so that the ash entering through the air discharge slots in the grate surface, will readily nd its way into the lower or outer end of each bar to be discharged therefrom when said lower open ends of the bars pass over an opening 49 (see Fig. 3) in the upper surface or wall of the ash ring upon which the outer ends of these bars rest and slide, the outer open end of each bar passing over said opening once during each complete rotation of the ash ring. 4 In order that the discharge end of each bar may be gradually opened as said end asses` over the opening 49said opening is e ongated with its length extending diagonally of the upper surface of the ash ring `and its circular path of travel. The air pressure chambers of the several bars are therefore swe t clean once during each rotationof the ash ring and during the remainder of `such rotation, are closed by said ring except that thc air under pressure contained in said chambers may at all times escape through the narrow slots' 47 in the gra-te surface.

In order to supply air under natural draft to the grate surface, the side of each grate bar 13 opposite that which is recessed to form the chamber 45, is cut away throughout a major portion of its length to form, together with the adjacent bar which is cut away in a like manner, a slot 50, which slots open through both up er and lower surfaces of the grate structure ormed by said bars and provide passages for the direct upward flow of airl through the grate from the space below, or the ash pit, thus providing for the supplying of air to maintain combustion upon the grate by natural draft so that the fire may be maintained, should the means for supplying air under pressure to the wind box fail for any reason, and itis obvious that natural 4draft alone may be relied upon .to maintain combustion upon the grate, by reason of the forming of the bars in this manner at both sides and providing natural draft slots at both sides of each bar, eliminating the forced draft .air chambers. It will be noted that each. bar

adjacent its ends is of full width to contact adjacent bars and form tight joints therewith, providing in effect, continuous grate portions at the inner and outer ends of the bars, said inner ends thus together forming a wall to close or. substantially close the space between the upper end edge of the operating ring 14 and the outer edge of the twyer ring 9.

Preferably, the` retort member 8, adjacent its upper outwardly flaring end which is ,provided with the outwardly and'upwardly curved annular flange 10, is formed with an internal upwardly open annular groove 51 adapted to receive and retain ash for the purpose of insulating this portion of the magazine or fire pot against the extreme heat generated at this point due -to the entrance through the openings 11 directly above, of airA under pressure into the fire pot. Overheating of the retort woulddistill out coal gases from the coal in the retort, which gases would pass downward inthe retort throughthe coal in the chamber 3 and finally find their way out through the fuel passage 5. `This overheating is prevented by the insulation provided by between the base and upper part or body off the furnace, further insures adaptability and provides an inwardly extending fiange or ledge to surround the grate structure with a restricted annular opening between this flange and outervends of the grate bars so that theV discharge of ash and clinker from the grate may be regulated, said opening being such that it will be clogged by accumulation of ash and clinker lon the ash ring provided the ash ring is not moved, but a rotation of the ring will cause a discharge of the ash from the ring and therefore by regulating the speed of the ring, the discharge of ash and clinker may be accurately controlled to control the fire on the The construction whereby the retort ring cap'9 is detachably locked in place upon the retort and in turn detachably holds the several grate bars assembled upon their actuating ring 14, provides for ready assembly and disassembly, and an efficient movement of the entire grate structure is secured by the application of motion to the actuating ring 14 through the medium of two crank motions imparted in unison thereto by the pinions 22 and eccentric connection of the ring to these gears by the crank pins 34 on the gears and rigid arms 33 on the ring at diametrically opposite sides of the ring. The movement imparted to the grate structure is therefore a movement corresponding to the path of travel of the pins'about the two axes of the pinions and without ,rotation of the gratestructure upon its own axis. This motion as well-as the motion of the ash ring 13, is intermittent due to the turning of the ash ring by the pawl and ratchet which imparts a very or fire pot and' the 'ash and clinker is discharged from their outer ends on to the ash ring which, by its rotative movement graduall discharges it into the ash pit. This'longitu inal movement of the grate bars relative to the retort cap ring-9 which is stationary, also keeps the narrow air space between the upper ends of the bars and the outer edgepf said cap ring clear so that air under pressure may enter the fire all along the edge of the cap and maintain combustion at the upper ends of the grates where the fuel forced upwardly in the retortoverlows the cap ring.

The construction and arrangement of elementsof the present invention particularly adapts the same to a circular construction and makes it particularly adaptable to furnaces having circular fire chambers but obviously the construction and arrangement may be varied within the scope .of the appended claims, to adapt the invention to installations other than that illustrated. Further, the construction is such as to provide a very compact device which may be readily installed in a furnace baseof the usual dimensions with the neck portion 2 through which fuel is fed and air under pressure is conducted, extending through the usual base opening or ash door,

"with said neck portion rigidly secured to the base by means of a flange 52 on the neck bolted or otherwise secured to the base around the opening, so that the entire structure within the base is supported by the neck portion, with the space all around the structure and beneath the same within the base, free from obstructing supports and so that the ash and clinker may be readily removed from the base or ash pit.

Havingfthus fully described my lnvention,

- 1. In la furnace, the combination of a plurality of radially extending grate bars together forming a grate, and means for moving said grate bodily in a horizontal plane l along a'closed path having a vertical axis.

2.In a furnace, the combination of a plurality of radially extending grate bars. together forming a circular grate, and means for imparting to said grate a non-rotative bodily circular movement in a horizontal plane.

3. In a furnace,'the combination of a central fire pot, a plurality of grate bars together forming an annular grate surrounding said fire pot, and means for moving sald -bars central fire pot, a pluralit tending radially from sai fire pot and forming a grate surrounding the ot and movable relative thereto, means for eeding fuel into the lower end of the fire pot, and an ash ring at the outer ends of said grate bars.

6. In a furnace, the combination of. a central fire pot, a plurality of grate bars extending radially from said fire pot and forni'- ing'a grate surrounding the pot and movable re tive thereto, a twyer ring on the upper end of the pot, means for moving the grate relative to the pot and means for introducing air under pressure into the fire pot through said ring. 7. In a furnace, the combination of a central fire pot, a plurality of grate bars extending radially from said fre'pot and forming a grate surrounding the pot and movable relative thereto, said bars being formed to provide air discharge openings through the upper surface of the grate, a twyer ring on the upper end of said pot with its periphery overhanging the inner ends of said bars, means for introducing air under pressure into the fire pot through said ring and into the fire on the grate surface through Said air discharge opening, .and means for moving the grate relative to said fire pot.

8. In a furnace, the combination of a central lire pot, a plurality of grate bars extending radially from said ir'e pot and forming a grate surrounding the pot and movable relative thereto, a twyer ring lon the upper end of the pot withtits periphery overlying the -inner ends of said bars, anash ring at the outer ends of said bars to receive ash therefrom, me ans for moving said errate as a whole, relative to said pot and to sald ash ring, and means for moving the ash ringy relatively to the outer ends of said bars to effect the disof grate bars excharge of ash from the outer ends of the bars. Y

9. In a furnace, the combination of a centralfire pot, a plurality of'grate bars ex-4 tending radially from said fire potand forming a grate surrounding the pot and movable relative thereto, a twyer ring on the upper end of the pot with its periphery overlying the inner ends of said bars, an annular member supporting the inner ends of'said bars, an ash ring supporting the outer ends of said bars, and means for moving said annular member to' move the bars lengthwise.

10.I A furnace as characterized in claim 9 including means for rotating said ash ring about the axis of the-fire pot.

11. A furnace as characterized in cla'im 9 wherein said means for movingsaid annular member is actuated by @rotative movement of said ash ring.

12.` An automatic .stoker for domestic furnaces having a base provided with an opening in'one side thereof, said Stoker in-v cluding an upwardl extending fire pot, a

neck portion extending laterally 'of the fire Y pot and forming a fuel Vpassage leading to the from the-upper end of the wer end of the extended throug A and secured to .the base adjacent the o n'- ing, means in said neck portion for f in fuel into the lower end ofthe fire pot, an a grate structure to receive fuel overflowing fire pot,said stokate and fuel feeder including said'ire'pot,

in said base solely inglmeans being suppo by said neck portion.

13.. A device ef che character described *end as characterized in claim 12, and whereinV said neck ortion provided with a passage for air un erl ressure and a t er 1s mount- *ed upon the re pot and provided with air passages opening into the fire pot and coinmunicating with said passage in said neck portion.

14. A device of the character described and Vzas-characterized in claim 12, and wherein a driving shaft extends longitudinally of'said neck portion therein and 'means is provided structure `and move at the inner end of said shaft 'for transmit-` ting motion therefrom to operate the grate A the same relative to the 15.'Avde v1ce of the character described i and as set forth in claim 12, and a filler ring for interposition between the upper end of the .furnace base and upper part of the furnace.

`16. A deviceof the character described and as set forth in claim 12, and a `filler rin for interposition between the upper end o the ,furnace base and upper part of the furnace,

Y Vsaid, ring bein provided with a Ilan e extending inwar y toward the end of sai grate structure to restrict the discharge of ash and clinker from the grate.

17. An automatic stoker for domestic furnaces having a base provided with an openl portion for feeding fuel into the fuel chamber, means int-he fuel chamber for feeding fuel into the' lower end of the fire pot, a frate structure extending radially from the Ere pot to receive fuel overflowing therefrom, said grate structure being mounted upon the structure forming the fuel chamber and neck portion, and means for moving the grate. structure relative to the ir'e pot.

18. An automatic Stoker as'characterized in claim 17 and further characterized in that .Said structure forming said fuel chamber is .also provided with a -wind box and said neck portion of` the structure is formed with a t, said neck portion being the opening in the baseVv passa e 'for air under pressure leading'to the i wind ith air passages opening into the pot and communicating with the wind box.

' 19. An automatic stoker as characterized in claim 17 and further characterized in that said neck portion is of a length .to position the x, and a twyer o n the fire pot formedV i fire pot centrally of said base and said grate v I structure com rises p uralify extending ra 'ally froin sai fire pot with their inner ends supported adjacent the upper eid of the pot, and an ash ring forming a support for the outer. ends of said bars and movable relative theretov and upon which the bars are free to` move when the grate structurl is moved relative to the fire pot.

20. An automatic Stoker as characterized of grate bars in claim 17 and further characterized in that said neck portion is of a length to position the fire pot'centrally of said base and said grate structure comprises 'a plurality of grate bars extending radially from said fire pot with their -inner ends supported adjacent thc 11D i ed upon the structure forming the fuel cham- 'ber and support for the lire tion about the fire pot axis.

21. An automatic Stoker as characterized pot, for rotain claim 17 and further characterized in that said neck portion is of a length to position the fire pot centrally of said base and said "'ate structure com rises a plurality of grate ars extending ra 'ally from said fire pot with their inner ends supported adjacent the upper end` of the pot, an annular ash ring having an outer ends o bein formed with outwardly and downwarily stepped annular surfaces and mounted upon the structure forming the fuel chamber and support for the fire pot for rotation about the fire pot axis, and an annular filler ring for interposition between the furnace base and upper furnace structure, said ring bein war y over the stepped portion of the ash ring and restricting t tween the outer ends of the the yfurnace wall.

22. A furnace Stoker including a supp`orting struct-ure forming a wind box and a fuel chamber, a fire pot mountcdcupon said fuel upper flat surface upon which the the grate bars rest, said ash ring grate bars and chamber, a twyer mounted upon said fire pot eannular opening be-v formed with a flange extending inand formed with a'ir passagesopening into the-fire pot, a member providing a wall forming an upward extension of the wind box and movable relative thereto, a series of grate bars engaging the upper edge of said Wall provided by said member and movable therewith, a flange on said twyer overlyin the upper ends of the grate bars, saidwin -box claim 22 and including an ash receiving member upon which the outer ends of the grate bars are supported to move freely thereon and to span the space forming an upward extension of the wind box and said ash receiving member, and

means for moving said member forming the upward 'extension of the wind box wall, to

move the grate bars relative to said twyer. 24. A furnace stoker including a memberproviding a Wind box, a fuel chamber and a passage leading to the fuel chamber, an upwardly open and flared magazine. on said fuel chamber to receive fuel therefrom and forming a fgepot, a twyer ring on the upper end of' said magazine and formed with air passages communicating with said wind box,

the magazine, with lugs to pass and a series of grate bars extending radially from the magazine with the1r inner endsunderlying the outer edge of the twyer .witl a narrow 'space therebetween communicating with the wind box, said grate bars together forming a grate surrounding the {ire p ot and chambers within the grate with openings from said chambers through the grate surface, said chambers being in communication with the wind box through the inner ends of said bars.

25. A furnace stoker as characterized in claim 24 and wherein said grate bars are tapered longitudinally in plan view, with their outer .ends of greatest width, whereby an annular grate is formed by placing said bars side by side and in contact throughout their length. A I- 26. A furnace Stoker as characterized in claim 24 and further characterizedin that the air chambersinsaid grate open through `an outer end portion of the bars, and in that a rotatable member is provided upon which the open outerends of thebars rest to close said ends, said member being provided with an opening to register with the open ends of the barduring the rotation of the member relative to said bars.

27. A furnace stoker including a vertically arranged magazine with open upper and .lower ends andformed with 'an outwardly extending ange adjacent its upper end formed with notches, a twyer ring on said magazine formed with air passages opening into the upper end of said magazine and formed with downwardly extending portions to center said twyer upon said flange on said portions being provided throughthe notches in said flange and detachably hold said twyer in place.

28. A furnace Stoker as' characterized in between said member said twyer ring is formed with an outwardly extending peripheralange to overlie the inner ends of grate bars, and a series of grate bars is supported side by side and in contact and in radially extending position to form an annular grate surrounding said magazine with the inner ends of said barsxproj'ecting beneath the outwardly -extending flange of said twyer ring. v

29. In a furnace Stoker, the combination' of a member forming av wind box open at the top, a fuel chamber open at the top and a fuel passage leading tothe chamber, a magazine mounted upon the fuel chamber to receive fuel therefrom, means for conveying fuel through said passage into said chamber,

an annular twyer on the upper end ofthe magazine formed with air passages opening into the magazine, an Vannular member uponthe wind box forming an upward extension of the wall thereof surrounding the magazine,

-a series of grate bars operatively and detachably connected to and resting upon the upper edge of said annular memberand together substantially filling the space between said edge of said annular member `and the annular outer edge .of said twyer with said bars together forming' an annular'grate surrounding the maga e, an ash ring rotatively supported upon sa d member forming said fuel passage, fuel chamber and windbox, upon-which ash ring the outer ends of said grate bars rest, and means for moving the annular memberupon which the inner ends of the grate bars rest, to move the grate relative to' the magazine and twyer.

" 30. A furnace Stoker as characterized in claim 27 and further characterized'in that claim 29 and including a pawland ratchet for rotating said ash ring about the axis o f said magazine and said means for moving saidannular member upon which the innerends of the grate bars rest, includes cranks operatively connected to said annular member.`

31. In a furnace, the combination of a` lurality of grate bars forming a grate, an rotating means for imparting to said grate, a circular motion in a horizontal plane, said lmotion being .defined by the revolution of said rotary mean ing axes.

32. In rality of gratebars forminga grate, means for imparting to said grate, a circular motion in a horizontall plane, said means including a plurality of cranks simultaneously rotatable about separate upwardly extending axes and defining by their revolution about said axes said circular motion.

and

In testimony whereof I affix my signature.

- WILFRED A. HARE.

about upwardly extend- 1 a furnace, the combination of .a plu-

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