US2370246A - Stoker - Google Patents

Description

e; E?, 3945. F. G. JAULY'AN E-rAl.l

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the removable cam segment for the Patented Eet. 21, A194s Fred G. Julyan and William M. Schweickart, Euclid, Ohio, assignors to Pocahontas Fuel Company Incorporated, New York, N. Y., a corporation of Virginia Application August 3, 1940, Serial No. 350,500

8 Claims.

This invention relates to stokers and particularly to those made for domestic and analogous uses.

The object oi the invention is to provide a domestic type stoker which is simple, easy and inexpensive to make and install, which may be I readily assembledvin a variety of arrangements with a minimum of changes and extra parts so as to accommodate diierent installation conditions, which is rugged and durable, which is clean and emcient in operation and which requires a minimum of attention.

In the accompanying drawings,

Fig. 1 is a plan view of a stoker embodying the various features of ,this invention;

Fig. 2 is a side elevation of the stoker shown in Fig. l;

, Fig. 3 is va vertical sectional view oi the burner unit taken along the axis of the conveyor;

Fig. 4 is a front elevation view of the burner unit taken transverse to the conveyor;

Fig. 5 -is a vertical elevational view ofthe motor unit of the stoker shown in Fig. 1, taken transverse to the conveyor as indicated by the line I-IB in Fig. l;

Fig. 6 is a side elevational view of the motor unit taken. as indicated by the lines Ii-II in Fig. 1;

Fig. 7 is' an enlarged diagrammatic view of the drive unit,the ilgure consisting of a series of views A, B, C and D taken substantially as indicated by the lines AA, BB, CC and DD, respectively in Fig. 6, with certaindetails omitted or shown schematically for simplication; andv Figs. 8 and 9 are plan and elevational views of shaker shaft driving mechanism.

Referring to Figs. 1 and 2, the complete stoker consists of a burner unit I, an ash disposal unit 2 and a "drive unit 3, as shown, in conjunction with a. suitable coal supply or pick-up unit, not shown. The latter preferably consists of a coal collector unit of the type shown and described in William M. Schweickart and Fred G. Julyan, Patent No. 2,306,189, issued December.22, 1942;

this unit being positioned in the coal bin serving' to collect coal and feed it into the bin end of the conveyor pipe 4 and is driven from the bin end of the conveyor screw l.

Conveyor screw l operates within a conveyor tube or pipe 4 extending from beneath the burner unit I to the coal collector unit. It necessary, the conveyor 4. i may include' a suitable knuckle,

netshowmtoenablethecoaitobefedfroma bin which is at an angle to the portion of the conveyor 4, 5 adjacent the burner unit.

Referring now also to Figs. 4 and 5, the burner unit I consists of a burner body 6 tting over the conveyor pipe 4 and clampedin position by the burner body yoke l. The top of the pipe 4 is provided with a generally circular coal opening 8 the edges of which are engaged by the bottom of the inner annular retort surface 9 provided in burner body 6. Secured to the top of the burner body is the retort base I0, the interior annular surface Il thereof 'forming an upward continuation of the retort surface 9. Positioned above and secured to retort base I0 are the tuyre segments I2 having peripheral surfaces 26, 2l, openings 35, 3l and radial ribs 34.

Burner body B has a hollow portion I3 with a rectangular opening at one side of conveyor pipe 4 for receiving the burner end of the rectangular air tube I4. From this opening the burner body has a passageway I5 communicating with the annular air chamber I6 formed therein between the inner annular wall 9 and an outer annular wall I1, this air chamber I6 being positioned above the conveyor pipe 4. Retort base III is provided with an annular air passageway I8 between the inner annular wall I I and an outer annular wall I8, this air passageway I8 communicating with the burner air chamber` I6 Vbelow and the interior of the tuyre segments I2 above so that' the air from the air tube I4 flows up into and around burner air chamber I G, up through air passageway I8 and into the tuyvre segments I2.

Y furnace between the burner unit I and the interior furnace walls and is provided in two or more parts so that its inner edge can be positioned between thedead ring shoulder 43 and the hook on the dead ring overlying the shoulder 43.

vFrom shoulder 43 the dead ring 42 inclines inwardly and downwardly to formA an ash chamber 43 below the grates 41, and then, from about 'beneath the outer edge of the rotating ash table 4l. the stationary dead ring 42 inclines inwardly supported upon and upwardly substantially parallel to the outer portion of the ash table 48, with the inner edge 49 of the dead ring 42 extending vertically into a groove 50 in the ash table. There is thus formed an annular pocket 5I which maintains a seal of ashes between the rotating ash table 48 and the stationary dead ring 42.

Ash table 48 is a one-piece ring rotatably supported on the burner unit I by the balls 53. The inner portion of the ash table 48 is forked to provide an annular inwardly directed V-shaped groove 54 the surfaces of which engage the balls 53 above and below the centers thereof. The balls themselves are mounted in an outwardly directed V-shaped groove 55 formed at the junction of the outer annular walls I1 and I9 of the burner body 6 and retort base I0. l

The outer annular wall I9 of the retort base I has a pocket 58 in which the top of the upper fork 51 of the ash table extends and also has a downwardly and outwardly extending projection 58 generally lying above the upper ash table fork 51. These surfaces thus cooperate to form an annular space 80 which maintains a seal of ashes between the stationary retort base |18 and the rotating ash table 48 and also to prevent the ash from leaking into the ball bearing support for the ash table. The bottom outer portion of projection 58 is formed with a pluralityof ribs 59 inclined about 60 from the radius, so as to tend to feed the ash-outward1y and thus further tend to prevent the leakage of ash past this seal.

Ihe underside of the portion of the ash table 48 lying above the ash pocket 5|- is formed with ribs 6I substantially tangent to the inner edge '49 of the dead ring and so directed that the ribs 8l tend to move the ashes outwardly from the pocket I.

Supported upon the ash table 48 are the segments of the grate 41. Assembled, the grate 41 is an annular ring extending from near the bottom of the outer surface 21 of the tuyre segments l2 to just above the outer edge 43 of the dead ring 42.

The grate is provided in four sections each of which has a downwardly projecting boss 81 near each radial edge which engages the upwardly extending bosses 88 formed on the ash table 48. In addition, each grate boss 81 has a toothed lug 89 which fits under a bridge portion 18 formed in each ash table boss 88 for securing the grate segments in place. One of the toothed lugs 89 for each grate segment is shorter than the other so that the grate segment is placed in position by first fitting the long toothed lug 89 under its bridge 10 then lowering the grate seg-V ment so that the short toothed lug 89 is opposite its bridge 18 and then circumferentially moving the grate segment until the short toothedV lug is under its bridge.

The underside of ash table 48 is provided with the radial teeth 12. These teeth, shown best in Figs. 5 and 6, are engaged by the tip 18 of the grate pawl 14 for rotating the ash table 48 and grate 41. The'grate pawl 14 is pivotallymo'unted near its center upon the upper end of pawl yoke 15, the grate pawl having its end 16 opposite the tooth-engaging tip 18 weighted in order to maintain the pawl tip in engagement with the ash table teeth 12. The pawl yoke 18 is supported upon and secured to shaker shaft TI at its burner end, where the the burner body yoke 1.

During the rotation of the ash table 48 the ash carried thereby is scraped therefrom by the stationary blade 18 provided on the dead ring 42, the blade scraping the ash into an ash discharge conduit 19 provided in the dead ring.

In assembling the burner unit I the burner body 8 is lrst rclamped to the conveyor pipe 4 by means of the burner body yoke 1. The dead ring 42 is then secured to the burner body (if not previously secured thereto) and then the ash table 48 andballs 53 are put in place. Theretort base I0 is then secured to the burner body, the tuyre segments I2 then inserted on the retort base as described, and then the grate segments41 put in place, as described.

The burner body 8 may be provided with a vertical plate parallel to the conveyor pipe 4 on the side thereof opposite the air tube I4, this plate being removable and held in place by the screw 82. Plate opens into a clean out pocket below the air chamber I8 to enable access thereto for removing any ash or other material which may accumulate therein. To enable a complete clean-out of the air passageways, a cleanout ring 84 may be provided in the air chamber I6, this ring having a series of spokes 85 so that upon manual rotation of the ring from the clean out pocket the otherwise inaccessible material in the air. chamber I6 is brought around so .that it falls into the clean out pocket. The clean out ring 84 is made in two pieces which are welded or otherwise secured together after the ring is positioned in place.

The coal flight 88 of the conveyor screw 5 for conveying the coal from the coal collector into the burner unit I terminates below theburner unit short of the center of the burner unit but within the outer edge of the coal output opening 8. The conveyor screw 5 is provided with a short reverse coal flight 89 commencing beyond the center of the burner unit and within the coal output opening 8. The adjacent ends of the coal flight 88 and reverse coal ght 89 are substantially abrupt and are positioned oppositely about the axis of the conveyor screw.

The coal is thus drawn to the burner unit I by the coal flight 88 and then pushed up into the enclosed portion or retort 9, II, 28 of the burner unit by the coal and reverse coal flights 88, 89. Some ofthe coal is lburned within the retort while the rest of itis burned above and outside of the retort. When the coal is a coking coal, much of the coking occurs within the retort, the coke then burning above and outside vof the retort. The ash resulting from the combustion sifts or is shaken through the grates 41, into the ash pocket 48, is carried by the ash table 48 around to the ash discharge conduit 18 and is there removed from the table by the scraper or blade 18.

-The burner unit described is durable, simple in construction, and contains few expensive parts. Thus, only the tuyre segments l2 and the grate segments 41 need be made of expensive heat-resisting material, and these are such that there is a minimum of tool Aworl: upon these parts. All the remaining parts are either sumciently air cooled or protected from the heat of the combustion as to enable them to be made of cast iron end of the shaft is pivotally or other materials which are not 'only inexpensive but easy to fabricate.

The ashes from the burner unit I which are discharged through the burner unit ash discharge conduit 19 drop down into the conveyor pipe 4 through an ash input opening |88 in the top o! the pipe (see Figs. 2 and 3). `Preferably the opening is provided with an ash receiving member |0| clamped to the conveyor pipe 4 and having a flange |02 tting around the sides of.

ash input opening |00 the conveyor screw 5 has v 5 between the adjacent ends of the reverse coal flight 89 and the ash night |03 is a dam |04 separating the coal and ashportions of the conveyor'pipe 4. The dam |04 preferably consists of a plurality of discs of substantially the same radius as the inside surface of the coal conveyor pipe 4. These may be made in sections and welded or otherwise secured together after the flights are formed on the screw 5 or they may be mounted upon the screw shaft before the flights are formed thereon. Preferably, the conveyor darn |04 is free to rotate with respect to the shaft of the conveyor screw 5.

Referring now to Figs. 1, 2, 5 and 6, the drive unit 3 comprises a base |4| which is secured to the drive unit end of conveyor pipe 4. Secured on base |4| is a. motor |42 the shaft of which drives a worm. |43 and the rotating element of the fan |44. Worm |43 drives a worm gear |45 secured upon a tubular shaft |46. The right hand end of this shaft |46, as viewed in Fig. 6 rotatably supports a sprocket |41 which is releasably secured by a suitable clutch |48 to the shaft |45. This clutch |48 is operated by the knob |49.

Meshing with the sprocket |41 is the chain |50 and this in turn meshes with the sprocket |5I on jack shaft |52. Jack shaft through the drive unit base |4| to the left of the base, as viewed in Fig. 6', where the sprocket |53 ismounted thereon. Sprocket |53 meshes with chain |54 and this in turn meshes with sprocket |55 fastened onthe extension |56 of the tubular shaft portion of conveyor screw 5.r

The base |4| has a cylindrical passageway |51 in alignment with the conveyor pipe, and the conveyor screw shaft extension y.| 56 passes through passageway |51 and projects slightly beyond the left side of the base |4|, as viewed in Fig. 6. To this left side of the base |4| is se'- cured a bearing member |58 for the extension |56, this member also closing the passageway |58.

The motor |42 thus drives the conveyor screw 5 from the ash end thereof and the conveyor screw 5, which is in.one long piece and operates in one long continuous passageway provided by the conveyor pipe, drives the coal collecting unit from the coal end thereof, rotates its coal flight 88 to convey up to the burner unit the coal delivered to the coal endof conveyor screw 5, rotates the burner end of its coal flight 88 and also the reverse coal flight 88 to force the coal up into the burner unit, rotates its ash flight |08 to conveyv the ash from under the burner unit over to the ash disposal unit and rotates the ash disposal unit end of its ash flight |03, and also rotates its reverse ash flight ||1 and its parallel bar ||8, to force the ash up into the ash can of the ash disposal unit. A

The drive unit 3 drives the shaker shaft 11, and thus the ash table 48 and grate 41 of the burner unit |,-by means of a shaker shaft driv- |52 extends ing mechanism schematically shown in Fig. 7.

For a complete understanding of this mechanism reference should also be made to Figs. 5 and 6.

Secured to the jack shaft |52 is an eccentric |10. 'I'his eccentric operates within a spur gear |1l. To this gear |1| is secured a pinA |12 which extends laterally into-a vertical slot |13 provided in a sationary part |14 of the drive unit (such as the base |4I) -so that this pin |12 prevents 'the-,spur gear |1| .from rotating. Thus, as the jack shaft |52 rotates, the center |15 of the spur gear |1| moves in a substantially circular path around the axis |16 of the jack shaft |52.

Rotatably mounted upon jack shaft |52A and concentric therewith is the annular gear |11. In the structure shown there are two more teeth in the annular gear |11 than in the spur gear |1|, the former having thirty-six teeth andthe latter thirtyffour teeth. The successive teethof spur gear |1| mesh with the successive teeth of the annular gear |11 as the jack shaft rotates, this action being the result of the eccentric |10 and the movement which it imparts to the spur gear |1|. Thus, at the end of acomple'te revolution of the Jack shaft, and thus at'the end of a com' plete cycle ofl the `resulting oscillation of the spur gear |1| about a substantially circular path. the annular gear |11 is moved forward a distance corresponding to the excess of the number of teeth on the outer gear |11 over that on the inner gear |1|, these excess teeth being those on the outer gear |11 not engaged by the teethon the inner gear |1| during a complete cycle of inner gearmovement. In other words, when the inner gear |1| makes a complete cycle and returns to its initial position, it causes the thirtyfourth tooth of the outer gear |11 to be in the position originally occupied by vthe thirty-sixth tooth on theouter gear |11, so that the outer gear |11 has moved around a distance corresponding to two teeth. The gears |1| and |11, in con-f junction with eccentric |10 and pin |12, thus providean internal epicycloidal gear train having a large gear reduction ratio.

The annular gear |11 is integral with. the disc |18 which has the hub |19 by means of which the annular gear is rotatably supported upon the jack shaft |52. AThe disc |18 has integrally formed thereon one cam segment |a and is provided with -two thin radial Spokes |8| on which additional camV segments |80b (see Figs. 8 and 9) may be mounted by a fastening screw passing through the'aperture |82 therein andl threaded into the disc |18.

secured to the shaker shaft 11 at the drive una'A end thereof is the cam follower arm |88 having a roller |84 pivotably supported at its outer end and positioned to engage the cam segment |80a, and such of the removable segments |805 as are in place, during the-rotation of the disc |18.

Also secured to shaker shaft 11 is the stop arm |85 having an arcuate outer face |86. A stationary part |81 of the drivefunit 3 positioned above stopA arm |85 is provided with a plurality of holes into. any one of which a removable stop pin |88 may be inserted with its lower end projecting into the path of the end |88 of the stop arm arcuate face |86. One end of a tension spring |80 is secured to the stop arm |85 with the other end secured lto a stationary part of the' drive unit.

the cam follower arm |83 counterclockwise, as 'viewed in Figs. 5 and '1, against the action of spring |80. This rotation of the cam follower arm |83 correspondingly rotates the shaker shaft 11. This results in a counterclockwise rotation of pawl yoke at the burner unit (see Fig. .4) so as to cause the pawl 14 to.move the ash table 48 (and thus the ash grate 41) a distance corresponding to the extent to which the shaker shaft 11 is rotated.

The counterclockwise rotation of cam follower arm |83, and thus the corresponding movement of the parts driven' thereby, ceases when the tip of the cam segment |80a rides under the roller |84. The spring |90 then becomes effective to return the parts toward their original position, the `speed of the return being governed by the rotation of disc |18 and the rear face of cam segment |80a. The return movement of the parts ceases when the end |89 of'arcuate face |88 on the stop arm |85 engages the stop pin |88.

By adjusting the position o f stop pin |88 the range of movement of shaker shaft 11 may be adjusted so as to regulate the amount of rotation imparted to the ash table 48 and grate 41 for each operation or throw of the grate pawl 14. In the construction shown, the range is from zero to four teeth or notches on the ash' table and grate for each pawl operation.

The frequency with which the grate pawl operates is adjustable by means of adjusting the total number of cam segments on the disc |18, this adjustment being provided by the two removable cam segments lllb. l

The total amount of rotation imparted to the ash table and gratey over a given period of timeconveniently termed the speed of rotation of the ash mechanism of the burner unit-is thus the aggregate of the number of notches for each grate pawl operation for as many grate pawl op of rotation of the ash mechanism very much le. than the motor speed, while affording by simple means an adjustment of the' ash mechanism speed over a very substantial range compared to the median speed of the ash mechanism. By this control of the speed of the ash mechanism of the burner unit, the stoker installation may readily be initially adjusted to the speed best suited to the installation, and then the user may readily vary this speed over a substantial range in ac cordance with weather or other conditions related to the action of the nre. This control thereby enables the stoker to be operated at high efficiency and to produce a minimum of unburned fuel inl the ash. For example, the user, by adjustment of the stop pin, may increase the normal speed of the ash mechanism during the severe winter months and decrease its speed during the summer months (at which time the only function of the stoker is to supply hot water).

It is to be noted that the adjustment of the stop pin |88 may be made at any time, for the stop pin will drop down into place to engage the .end |88,of stop arm |85 after the arcuate face |88 of the stop arm has moved out from under the bottom of the stop pin. Thus, with the parts as shown in Fig. 7, and assuming the stop pin is moved from position 4 to position 2, the ensuing operation of the grate pawl is four notches, but during this operation the face |88 moves from under stop pin |88 so that the stop pin falls to its lowermost position. As a consequence, the end |89 of the stop arm is stopped on its return in the two-notch position so that all further grate pawl operations will each be two notches.

The stoker described is particularly flexible in the manner in which it can be assembled to provide different arrangements suitable to different installation conditions.

erations as occur during the given period of In the construction shown the range of speed which can be imparted to the rotating ash mechanism of the burner unit is large, varying fromy one notch to twelve notches for one revolution of disc |18. 'I'he possible adjustments and the resulting speed are as follows:

Total number oi notches of Position of rotation of Number ofl cam segments on disc 178 stop pin 188 grate for one revolution of 'disc 178 AAs a result of 'this construction the uniform rotary motion of the stoker motor is transformed to. an intermittent. rotary motion of ,the .ash mechanism ofthe burner unit with the speed 1I ash table and A www www MNH t.. can mosh-ba .09#

1. A Stoker having a continuous passageway \and a single conveyor screw operating therein,

said screw having a coal night for conveying coal in one portion of the passageway toward and up into the stoker burner and having an ash night for conveying ash in another portion of the passageway from the burner unit toward an ash receptacle, the burner of said Stoker having a rotating ash mechanism, means connecting the stoker motor with the ash end of said screw beyond the end of the ash night for rotating the screw, and means directly connecting the stoker motor with the rotating ash mechanism on the burner so that the drive for the ash mechanism does not include the conveyor screw.

2. A stoker as set forth in claim 1 in which the means connecting the stoker motor with the rotating ash mechanism comprises a shaker shaft, gearing connecting said shaft to said motor and acting to oscillate said shaft, meansat the other end of said shaft acting to rotate said ash mechanism from said shaft. and adjustable means regulating the amount of rotation of the aah mechanism for each oscillation of the shaft.

3. In a stoker mechanism a retort having an upper portion with a vertical passage for the coal and a lower separable portion.' a feed tube of substantially constant diameter passing between said portions of the retort and having an orince intermediate its ends and positioned to open upward into the vertical passage of the retort, means for clamping said upper and lo'wer portions of the retort around said tube rigidly to fasten the parte together and means within the tube for. feeding. coal horizontally to said orinee therethrough into the vertical passage of the retort -4. In a stoker mechanism a retort having an upper portion with a vertical passage for the coal and a lower separable portion and an ash ring surrounding the upper portion of the retort and having a downwardly directed outlet for the ashes, a feed tube of substantially constant diameter passing between said portions of the retort and having a plurality of orices located intermediate its ends and positioned to open upward, one orifice leading to the vertical passage of the retort and the other orifice receiving the discharge of ashes from said outlet, means for clamping said upper and lower portions of the retort around said tube to rigidly fasten the parts together, and means within the tube for feeding coal horizontally to the orifice leading upward to the retort and upward' through said orifice into the vertical passage of the retort and simultaneously feeding ashes horizontally receivedv through the orifice at the said ash outlet.

5. Stoker mechanism as set forth in claim 4 in which the feed tube has a third orice located between the ends of the tube and opening upward for the discharge of ashes and the ash feed means within the tube has an end portion lifting' the ashes upward through said third orifice.v

6. Stoker mechanism as set forth in claim 4 in 7. In a stoker a drive unit comprising a motor,

blower and gearing driven by said motor, a combined ash and coal screw conveyor driven from said gearing,` a continuous straight ash and coal tube section connected at one end to said drive unit and housing said ash and coal screw, a burner unit including a retort member mountedv on an intermediate portion of said ash and coal tube and receiving coal from said coal screw and having a grate means delivering ashes to said ash screw, an ash disposal unit on said ash and coal tube between said drive unit and said burner unit and receiving ashes from said ash screw, and an air tube connecting said blower with the retort member of said burner unit.

8. A stoker combination as set forth in claim 7 in which the burner unit has a rotarypart connected by a shaft to be driven from the gearing of the drive lunit.

FRED G. JULYAN. WILLIAM M. SCHWEICKART.

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