US2248206A - Ash removal equipment for stokers - Google Patents

Description

July 8, 1941. R w. SUMAN 2,248,206

ASH REMOVAL EQUIPMENT FOR STOKERS Filed Feb. 29, 1940 4 Shets-Sheet 1 July 8,. 1941. R, w, SUMAN ASH REMOVAL EQUIPMENT FOR STOKERS v Filed Feb. 29, 1 940 4 Sheets-Sheet 2 3 1 IaieriWJmw July 8, 1941. R. w. SUMAN ASH REMOVAL EQUIPMENT FOR STOKERS Filed Feb. 29, 1940 4 Sheets-Sheet 3 fiam mmw ASH- REMOVAL EQUIPMENT FOR STQKERS Filed Feb. 29, 1940 4 Sheets-Sheet 4 man g 5 fi'Meri/l M I be driven.

Patented July 8, i

UNITED STATES "PA-TENT- OFFICE esn asmovanaommmu'r FOR s'roxr:

Robert W. Suman, Chicago, 111., assignor to Link Belt Company, a corporation of Illinois Application February 29, 1940, Serial No. 321,581 (c1. no -4s) 12 Claim;

This invention relates to new and useful improvements in ash removal equipment for stokers which is capable of breaking ash from around the margin of the fire or the burner head and collecting and delivering it to suitable containers, receptacles, bins, or the like, located outside the furnace or boiler.

Ash removal equipment of this type now available on the open market and disclosed in the prior patented art, naturally, has assumeda variety of diilerent styles, designs, etc., and embodies several difierent operating principles. 'A .careful study of these various mechanisms discloses the fact that there are several very objectionable structural and functional features which make their appearance in diilerent combinations and to varying degrees in all of them. Prior attempts to overcome certain ones of these objectionable features have caused others to appear. In other words, no prior worker in the art has been successful so far in developing a mechblower portions thereof. With certain stoker assemblies the prime mover is either located with- 1 in the front portion of acasing or housing which also encloses the hopper, or it is located outside of the front of the hopper. As this prime mover is essential to the operation of the stoker, it is employed 'as a source of power for driving the ash clipping, scraping, or slicing device, the ash anism which is free of all of these undesirable features.

To illustrate, a practical anthracite ash removal mechanism which is suitable for use as a part of a domestic underfeed or spillover stoker must be-eapable of removing the ash from around the margin of, the retort or burner head. Some suitable form of movable ash scraper, clipper, or slicer device must be used for this purpose and, of course, it must be driven. After the ash is removed from around the entire periphery of the burner head margin, it must be collected and moved to a point where it can be picked up by a conveyor device and removed fromthe ash pit of the furnace or boiler. This ash collecting device usually either takes the form of means for tunneling the ash to the conveyor device or movable blades ior accomplishing the same result. If it consists of movable blades, they, of course, must be driven. The conveyor device must pass through the wall of the furnace or boiler to reach the exterior thereof, and it usually is called upon to elevate the ash to a level where it may be discharged into one or more ash cans, or other This conveyor device must types of receptacles.

The conventional stoker apparatus usually includes either a coal hopper which is located a reasonable distance in iront'of the furnaceor boiler doors or a coal bin conveniently located with respect to the furnace or boiler. Coal and collecting device, and the ash conveying device. The drives for these ash handling devices, therefore, must take into account the locations of the devices relative to each other and to the source of power.

Quite -a number of the prior ash removal mechanisms employ inclined screw conveyors for removing the ashirom the furnace or boiler and carrying it to a suitable elevation for discharge into one or more ash cans, or the like. The discharge end of the screw for the conveyor usually is driven from the speed reducer which is connected to the prime mover of the stoker and normally is employed for driving the slow speed coal conveyor. To provide this type of drive necessitates the use of some form of gearing, usually of the chain and sprocket type, which must be' enclosed. If this drive is located at the end of the hopper farthest from the furnace or boilto be entirely removed from the building in which,

the stoker is located and deposited in outside receptacles or bins. This type of ash disposal requires an unusually long conveyor. conveyor screw is driven at its discharge end from a stoker motor located either within or outside the front portion of the casing or housing, it is impossible to provide an ash conveyor of sufllcient length to accomplish this desired result.

Most prior ash removal mechanisms take their drives for the ash clipping, scraping,. or slicing devices and the [ash collecting devices from the burner end of the ash conveyor screw. A rather common form of drive of this type employs the spiral flights of the conveyor screw as one element of a worm gear set and provides the burner head parts, which are to be driven, with the sec- 0nd gear element. This worm gearing operates in the ashes accumulated in the ash pit and is When the spur and/or miter gearing in connection with a counter or stub shaft for driving the ash collecting device from the conveyor screw. A casing must be provided to enclose this driving mechanism. As the casing and its gearing must be located in the ash pit, it frequently is difficult to install this type of equipment because of the ash pit dimensions.

When the ash clipper or scraper and the ash collector drive is of the first mentioned type, the

meshing of the conveyor screw flights directly with the worm gear which drives said devices necessitates locating the receiving end or the conveyor at a rather high level. The conveyor tube. therefore, is too high to pass through the conventional ash pit door opening and requires the cutting of a special opening in the furnace or boiler casing wall. The elevation of the receiving end of the conveyor, also, allows a rather thick layer of ashes to accumulate in the ash pit below the operating or receiving range of the conveyor.

In an endeavor to overcome the limitations placed on the permissible length of the ash.conveyor by driving the same at its discharge end directly from the stoker prime mover and to lower the height of the ash conveyor where it passes out of the furnace or boiler, certain ash removal mechanisms employ a horizontally arranged screw conveyor which extends from within the ash pit to approximately the location of the coal hopper and then employ an inclined screw elevator which receives the ashes from the discharge end of the screw conveyor and lifts them to the desired elevationfor discharge. into a suitable receptacle. This arrangement materially increases the manufacturing costs for such equipment due to the considerably larger number of parts involved.

The driving of the burner head parts, i. e., the ash clipping or scraping device and the ash collecting device, from the receiving end of the ash conveyor screw necessitates supporting this end of the screw in a bearing. The discharge end of the screw conveyor also must be supported by a bearing because of the drive connection between the same and the prime mover of the stoker. These two bearing supports for the conveyor screw rigidly mount the screw and such a mount-' ing is responsible for the heavy scraping of the ash particles on the inner surface of the ash tube which results in developing considerable noise that is very objectionable.

It is a primary object of this invention to provide ash removal mechanism for stokers which employs a single inclined conveyor for withdrawing ashes from the ash pit and lifting them to any reasonable height for discharge into suitable cans, bins, pits, or the like, which may be located any necessary distance from the furnace or boiler, the said height and distance of discharge being made possible by the novel form of drive employed between the stoker prime mover "and the conveyor screw.

A further important object of the invention i to provide a greatly improved form of drive for the ash clipper, scraper, or slicer and the ash collector device which will extend directly from the stoker prime mover to these devices without involving the ash conveyor screw. These portions of this drive mechanism which are located with in the ash pit are of such a character as to be capable of operating in the presence of ashes without being subjected to rapid wear even though they are not separately encased.

Another primary object of this invention is to eliminate the need for employing the screw of the ash conveyor as a driving member for any portion of the ash removal mechanism so that the conveyor may be inclined and yet be sufficiently low at its receiving end to permit it to pass through the conventional ash pit door opening, and, also, to permit the receiving end of the conveyor screw to be left free from support by a bearing, whereby the screw may float in the ash tube and have far less tendency to cause noise by heavy scraping of the ash particles.

Still another object of the invention is to provide ash removal equipment which is not dependent upon any special design of stoker and, therefore, may be supplied as an accessory to standard stokers and applied thereto without materially modifying any part thereof.

Other objects and advantages of the invention will be apparent during the course of the followlowing description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

, Figure 1 is a side elevational view of a domestic, anthracite stoker of the underfeed or spillover type with one form of ash removal equipment embodying this invention operatively associated therewith.

Figure 2 is a top planview of the mechanism disclosed in Fig. l,

Figure 3 is a detail elevational view of the retort or burner head of the stoker and the immediately associated portions of the ash removal equipment, the said view being taken at a angle with respect to the disclosure of Fig. 1,

Figure 4 is a detail horizontal sectional view taken on line 4-4 of Fig. 1,

Figure 5 is a detail vertical sectional view of the retort or bumer'head portion of the stoker disclosed in Figs. 1 and 2 with a slightly modified form of ash removal equipment operatively associated therewith,

Figure 6 is a top plan view, partly broken away of the mechanism disclosed in Fig. 5,

Figure 7 is a detail, partly elevational and partly vertical sectional view of the mechanism disclosed in Figs. 5 and 6,

Figure 8 is a view similar to Fig. 5 but illustrates a further modified form of ash removal equipment, and

Figure 9 is a view similar to Fig. 6 but illustrates the modification of Fig. 8. l

In the drawings, wherein for the purpose of illustration are shown the preferred embodiments of this invention, and particularly referring to Figs. 1 and 2, the reference character l0 designates the casing or housing which encloses the. coal hopper and additional parts of a domestic stoker of the underfeed or spillover type adapted to handle anthracite coal. Although this type of casing or housing with its enclosed coal hopper has been selected to illustrate .the invention, it is to be understood that the ash removal equipment described herein might just as well have been illustrated with a coal bin feed type of installation. A suitable cover II is provided for the coal hopper portion of the casing in to permit filling the said hopper.

A combined coal feed tube and air duct l2 extends from the casing ii to the base I! of the burner head or retort which includes the flared tuyere section IL Fig. 2 generally illustrates the tuyre bars II arranged within the tuyere section ll. These bars are grouped around the cen- .of the burner head base 13.

bracket or casting 24 has projecting horizontal-' which may tral opening I6 through which the coal is fed upwardly to the fire, or bed of burning coal, not

' speed reducer unit 11 and drives this unit through suitable gearing 20, which may take the form of a V-belt and pulleys.

A mounting bracket 2| is suitably secured to the transmission unit 11 and carries a bearing Y 22 for supporting tl e front end of a horizontally extending drive shaft 23 having a sprocket wheel 24 mounted thereon. A roller chain 25 is trained over the sprocket wheels l8 and 24 for driving the shaft 23 from. the speed reducer unit l1.

The horizontal drive shaft 23 is illustrated in Figs. 1 and 2 as emerging from the rear end of the casing Ill and extending to a point adjacent the burner head base 13. A mounting bracket or casting 24 is provided with a securing flange 25 for attachment to the projecting portion 13a This mounting .end portion of the arm bevel gear casing 21 is attached to and keyed {to the drive shaft 23.

4|. The tube attaching 39 is curved or bent at 390 to fit around approximately one-half the circumference of the ash tube. A clamping strap, or the like, 42 is secured to the arm 39 and is shaped to cooperate with the curved or bent portion 390. of the arm to clamp the ash tube in place on the end of the arm. The miter or braced by the ash tube by means of a clamping strap, or the like,, 43, see Figs. 1 and 2.

- Journaled at its opposite ends in the miter or. bevel gear casing 21 and the spur gear casing 31 is a countershaft 44 which extends in parallelism with the ash tube 30. A miter or bevel gear 45 is keyed to the lower end of the countershaft and meshes with the miter or bevel gear 28 This meshing of these two gears drives the countershaft 44 directby means of a bracket ly from the drive shaft 23. Spur gears 46 are keyed to the upper ends of the countershaft 44 and the shaft of the conveyor screw for driving the said screw from the 'countershaft. These spur gears are mounted in the gear casing 31. Cover plates 41 and 48 are provided for closing the two gear casings 21 and 31, respectively.

It will be seen from this arrangement that the upper end, or discharge end, of the conveyor screw 35 is driven from the upper end of the 1y therefrom a spacer tube 26 through which the drive shaft 23 rotatably extends.

The remaining end of the spacer tube 26 is loosely fitted or socketed in the miter or bevel gear casing 21 through which the drive shaft r 23 extends. A bevel or miter pinion 28 is suitably keyed to the drive shaft 23 within the casing 21. 4

The mounting bracket or casting 24 has formed thereon a sleeve 29 in which is secured the lower end of an ash conveyor tube 30. Fig. 1 discloses this ashtube as being inclined, while Fig. 2 discloses the tube as extending laterally or at an angle with respect to the longitudinal center line of the stoker assembly so as to clear the adjacent side of the casing 10. This ash tube 30 may be of any desired length to enable it to dis charge the ashes into any desired receptacle located within the buildingin which the stoker is installed or outside of said building if this type of ash disposal is required. Figs. 1 and 2 disclose the ash tube 30 as having formed therein two openings 31 nipples or. tube sections 32 with the covers 33 be fitted to the tops of ash cans 34.

Rotatably mounted in the ash tube 30 is a conveyor screw 35. This screw projects from the lower end of the ash tube 30 and terminates, as is clearly illustratedin Figs. 1, 3, and 4, in close proximity to the burner head base 13 and just short of the floor level 36 of the furnace or boiler ash pit, not shown. This conveyor countersha-ft 44 which in turn is driven from the horizontally arranged drive shaft 23. If it is desired .to discharge ashes from around the burner head to a bin located outside of the build- I ing in which the stoker is installed, it is possible to extend the ash tube 30 to this distant point and still drive the conveyor screw at its upper or discharge end from the countershaft 44 be.- cause this countershaft can be extended so as to correspond with the length of the ash tube Figs. 1 and 4 disclose a bracket 49 attached to the projecting portion l3a of the burner head I base l3. This bracket carries a bearing 50 in which are connected by short screw extends the entire length of the ash .tube

30 and the shaft of the screw projects beyond the ash tube by means of the sleeve.

40 of the casing 10 which is mounted the hub portion 5| of a disc 52. The disc hub 5| is provided with a suitably shaped socket, not shown, to receive the squared or splined end portion 530i the drive shaft 23. This construction causes the end of the driveshaft 23 to drive the hub 55 and its disc 52. A crank pin 54 is suitably mounted on the disc 52. It will be appreciated that as the 'coal burns and fresh coal is fed upwardly through the central opening l6, the'ash or clinkers are forced outwardly radially. of the tuyere section 14 so as to overhang the margin of the same. For the purpose of breaking off the overhanging ash or clinkers, a clipper ring 55 is provided. This clipper ring is supported by the angularly shaped lever arm 55 and the short arm 56a, see Figs. 1 and 3, which are pivoted about diametrically arranged pins 51. This clipper ring 55 is caused to rock about the common axis of the two pins 51 by means of a pitman rod 58 which is connected at its lower end to the crank pin 54 of the disc 52 and at its upper end to the ears 59, carried by the clipper ring 55, by means of the pivot pin 60. Suitable, cotter pins, or the like, 6| are provided for maintaining these connections.

Journaled for oscillatory movement about the 0 line of juncture between the burner head base 13 and the burner head tuyre section I4 is an ash collector ring 62. This ring 62 hasformed about its periphery a, plurality .of mounting ears or lugs 63 to which are securedthe wedge. shaped teeth 64 that project radially-of the ring $2. zBy

inspecting Figs. 1 and 3, it will be seen that these wedge shaped teeth 64 are each provided with a fiat perpendicular face or longitudinal edge 65, while the remainder of the body of each tooth tapers away from this perpendicular face.. Figs. 1, 3,and 4 clearly disclose these teeth 64 as being spirally arranged. around the periphery of the ring 62. In other words, the mounting lugs or ears 63 are suitably shaped to support the teeth 64 at different elevations. The tooth 55 which is arranged closest to the receiving end of the ash conveyor screw 35 is arranged at the lowest point of the spiral, or partial convolution, collecarranged in a notch 61 formed in the lower end of the mounting lever 56, which partly supports the clipper ring 55. In other words, the lower end of this mounting lever 56 is bifurcated at 61 and the pivot pin 66 is positioned between the spaced furcations.

To explain the operation of this ash removal equipment, the drive shaft 23 may be rotated either intermittently or continuously, at the desired slow speed, from the transmission unit I'I. Through the miter gears 26 and 4 5, the countershaft 44 is driven from the drive shaft 23. The spur gears 46 drive the conveyor screw 35 at its upper endfrom the upper end of the countershaft 44. The projecting lower end of the conveyor screw will pick up the ashes from the ash pit of the furnace or boiler, not shown, and carry the ashes up through the tube, 36 to be dis-' charged into the cans 34, or other suitable receptacles.

To bring the ashesaround to the operating zone of the lower projecting end of the conveyor screw, the collecting ring 62 and its ash advancing teeth 64 are oscillated about the vertical axis of the burner head. The flat, perpendicular front faces 55 of the collecting teeth 64 cause the ashes to be advanced around the periphery of the burner head when the ring" 62 is oscillated in one direction. The return stroke or movement of the ring 62, and its teeth 64, will not bring about a retrograde movement of the ashes because of the tapered or wedge shaped bodyof the teeth.

The collector ring 62 and its teeth 64 are oscillated throughout the desired range of movement by the mounting lever 56 which partly supports the clipper ring 55. As this clipper ring oscillates, it will shear or break off the ash or clinkers which project beyond the margin of the tuyere section I4. This rocking of the clipper ring is brought about by the pitman connection between the ring and the crank pin 54 which is driven by the drive shaft 23. Y

It is obvious from the above description that the burner head parts, the clipper ring 55 and the collector ring 62 with its teeth 64, are driven by the drive shaft 23 entirely independently of the drive for the conveyor screw 35. The conveyor screw, therefore, may be located at a very low level at its receiving end with the result that the conveyor tube 30 may pass through the conventional ash pit door of the furnace or boiler in which the burner head is positioned. It is not necessary, therefore, to cut a special hole in the wall or casing of the furnace or boiler to accommodate the ash tube.

It has been determined that by supporting the shaft of the conveyor screw at its upper end only, or in a suitable bearing located in the spur gear casing 31, the remainder of the conveyor screw will fioat'or be permitted to partake of movement relative to the bore surface of the ash tube 30. This floating of the conveyor screw within the ash tube eliminates a considerable amount of noise which would be produced if the conveyor screw were supported at its opposite end portions in two or more bearings, because the floating screw will not scrape the ash particles heavily against the bore surface of the ash ube.

In Figs. to '7, inclusive. there is disclosed a modification of the ash removal mechanism illustrated in Figs. 1 to 4, inclusi've. This modification deals entirely with the ash collecting mechanism and its actuation from the clipper by means of the pin H.

ring. All of the remaining structural elements are the same as those disclosed in Figs. 1 to 4, inclusive, and for that reason the same reference characters will be applied to identical elements. It is to be understood, also, that the elements which are disclosed in Figs. 1 to 4, inclusive, such as the casing i0 and its enclosed parts, the upper end of the ash tube 30, the ash cans 34, etc., are to be employed with the mechanism which is actually illustrated in Figs. 5 to 7, inclusive.

Specifically describing the modified structure, it will be seen that an ash collecting ring 68 is journaled for rotary movement about the periphery of the burner head base 13 and the tuyre section l4. This collecting ring 68'has projecting radially therefrom a plurality of ash engaging teeth 69. These teeth need not be of tapered formation because they always move in one direction.

To effect this rotary movement of the collector ring 68 and its teeth 69 in a step-by-step manner, the clipper ring supporting or mounting lever has pivoted on its lower end a pawl 10 This pawl is shaped above the pivot pin H to provide a laterally projecting arm I2 which acts as a weight and is the pawl I0 will engage one'of the teeth 69 and advance the ring 68 in a clockwise direction around the burner head base I3, when viewed from above. As the lower end of the mounting lever 56 swings backwardly or to the right, the curved rear surface of the pawl 10 will ride over the teeth 69 of the collecting ring 68. The collecting ring,,therefore, is not caused to partake of retrograde movement. shoulder 13, by engaging the edge of lever '56, causes the pawl 10 to drive the ring 68 when the lower end of the mounting lever 56 swings to the left. When the lower end of the lever 56 swings to the right, the pawl 70 will pivot about pin II and the offset portion or shoulder 13 will swing downwardly and outwardly away from the The offset portion or -When the pawl .bell crank lever I1.

per ring 55 into a step-by-step rotary movement for the collecting ring 68.

In Figs. 8 and 9. there is disclosed afurther modified form of mechanism for shearing the ashes or clinkers which project beyond the margin of the burner head and for around to the operating or receiving zone of the screw conveyor. This ash breaking and collecting mechanism is driven by a slightly modified means from the crank pin which is driven by the inner end of the drive shaft 23. All other parts of this mechanism will correspond with the parts disclosed'in Figs. 1 to 4, inclusive, and like ref-- erence numerals will be applied to identical elements. It, also, will be understood that the stoker parts and ash removal elements disclosed in Figs. 1 to 4, inclusive, and omitted from Figs.- 8 and 9 are to be used with the devices which are actually shown in these last two figures.

To specifically describe the modified structure disclosed in Figs. 8 and 9, the reference character 14 identifies the collector ring whichhas projecting radially a plurality of ash collecting teeth 15. A plurality of substantially L-shaped bars 16 are attached at their lower ends to' appropriate teeth 15. These slicer or suitably arranged with respect to the periphery or margin of the tuyere section Id of the burner head to break off the ashes or clinkers which project beyond this margin. The ashes broken off in this manner are moved around to the operating zone of the conveyor screw lecting teeth 15. 1

. It'is desired to have the collecting ring 14, with its teeth 15, and the slicer bars rotate around the burner head in a step-by-step manner in one direction. To accomplish this movement, a bell crank lever I1 is pivotally mounted by the pin |8 at one side of the burner head base l3. The arm 19 of this bell crank lever is pivotally connected to a link 80 by means of the pin ill. The

free end 82 of this link is connected to the crank pin 54 carried by the disc 52. pivoted to the remaining arm of the bell crank lever I! by means of a pin 84. Fig. 9 discloses the pawl as having a lateral projection or finger 85 which is adapted to bear against one longibreaker bars I6 are moving the ashes lower end It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. Ash removal equipment for underfeed stokers, comprising a burner head through which the coal is fed upwardly, tending from a point adjacent the base of the burner head to an elevated point of discharge, a screw conveyor arranged in said tube and extending beyond the burner head end thereof so as to be unconfined for picking upash at its from around the burner head and carrying it into and through thetube, a horizontal by the col- A pawl 83 is I drive shaft receiving itspower from the prime mover of the stoker and extending toward the burner head to terminate'adjacent thereto, a. countershaft arranged in parallelism with the ash tube, a gear connection between the lower end of the countershaft and an intermediate portionof the drive shaft. and a gear connection between a the upper ends of thecountershaft and the screw conveyor.

2. Ash removal equipment for underfeed stokers, comprising a burner head through which the coal is fed upwardly, an inclined ash tube extending from a point adjacent the base of the. burner head to an elevated point of discharge,

a screw conveyor arranged in saidtube and extending beyond the burner head end thereof so as to be unconfined for picking up ashat its lower end from around the burner head and carrying it into and through the tube, bearing means for rotatably supporting the upper end of the conveyor screw in said ash tube, the remainder of the length of said screw being free to fioat in said tube, a horizontal drive shaft receiving its power'from the prime mover'of the stoker v and extending toward but terminating just short of the burner head, a countershaft arranged in parallelism with the ash tube, a gear connection between the lower end of the countershaft and tudinal edge of the bell crank lever arm on which the pawl ranged on the same side of the pivot pin 84 as the finger 85. This second arm acts as a weight to hold the laterally projecting finger 85 against the edge of the bell crank lever.

When the perpendicularly projecting arm of the bell crank lever 11 is moved to the left, see

engages an ash collecting lever to bring about this action of the pawl in driving the collecting ring in one direction.

83 pivots about the pin 84, during the return movement of lever 11, the finger 85 will travel in an arc past the upper end of the perpendicular arm of hell crank lever I1. After the pawl has ridden over the next adjacent tooth I5, the arm 86 will returnthe pawl to its normal position with the finger 85' engaging the edge of is mounted. A second arm 85 is arthe collecting ring N with the, drive shaft, and a gear connection between the upper ends of the countershaft and the conveyor screws.

3. Ash removal equipment for underfeed stokers, comprising a burner head through which coal is-fed upwardly, an inclined ash tube ex tendingfrom a point adjacent the base of the burner head to an elevated point of discharge, a screw conveyor arranged in said tube and extending beyond the burner head end thereof so as to pick up ash fromaround the outside of the burner head andcarry it into and through the tube, a horizontal drive shaft receiving its power from the prime mover of the stoker and extending to a point adjacent the burner head, means for supporting the ash tube and the drive shaft from the burner head, a countershaft arranged-alongside of the ash tube, a drive connection between'the countershaft and the drive shaft, and a drive connection between the countershaft and the screw conveyor.

4. .Ash removal equipment for underfeed stokers comprising a stoker drive mechanism, a burner head, a drive shaft extending from the drive mechanism to a point adjacent to out extcriorly of the base of the burner head, means for supporting the end of the drive shaft from the burner head, an inclined ash tube, means for supporting the ash tube from the burner head, a

an inclined ash tube exconveyor screw arranged in the ash tube, a countershaft arranged parallel to the ash tube, means for supporting the countershaft from the ash tube, gearing drivingly connecting the lower end of the countersh afito the drive shaft, and gearing di'fv ing'iy c c mnecting the upper ends of the countershaft and the conveyor screw.

'5. Ash removal. equipment for underfeed stokers comprising a stoker drive mechanism, a burner head, a drive shaft extending from the drive mechanism to a point adjacent to but exteriorly of the base of the burner head, means for supporting the end of the drive shaft from the burner head, an inclined ash tube, means for supporting the ash tube from the burner head, a conveyor screw arranged in the ash tube,

bearing means for journaling the upper end of the conveyor screw in the ash tube, the remainder of the length of said screw being free to float in said tube, a countershaft arranged parallel to the ash tube, means for supporting the countershaft from the ash tube, gearing drivingly connecting the lower end of the countershaft to the drive shaft, and gearing drivingly connecting the upper ends of thecountershaft and the conveyor screw.

6. Ash removal equipment for underfeed stokers comprising a stoker drive mechanism, a burner head, a drive shaft extending from the drive mechanism to a point adjacent the base of the burner head and employed solely as a source of power -for ash removal equipment, means for supporting the end of the drive shaft from the burner head, an inclined ash tube, means for supporting the ash tube from the burner head, a conveyor screw arranged in the ash tube, a countershaft arranged parallel to the ash tube, means for supporting the countershaft from the ash tube, gearing drivingly connecting the lower end of the countershaft to the drive shaft, gearing drivingly connecting the upper ends of the countershaft and the conveyor screw,

mechanism associated with the burner head for breaking off the ash and delivering it to the lower end of the conveyor screw, and means for driving said mechanism from the horizontal drive shaft independently of its drive of the conveyor screw.

'7. Ash removal equipment for underfeed stokers including a burner head through which the coal is fed upwardly, comprising a clipper ring mounted to-rock about a transverseaxis adjacent the margin of the burner head for breaking off ash projecting beyond said margin, an ash collecting mechanism movably mounted on the base of'the burner head, a horizontal drive shaft receiving its power from the stoker prime mover, a crank and pitman connection for operating the clipper ring from the adjacent end of the drive shaft, and means for employing the rocking movement of the clipper ring for actuating the ash collecting mechanism.

8. Ash removal equipment for underfeed stokers including a burner head through which the coal is fed upwardly, comprising a clipper ring, a mounting lever rockably supporting the clipper ring adjacent the margin of the burner head for breaking of! ash projecting beyond said margin, ash collecting mechanism, including a ringhaving ash engaging teeth, mounted for movement about the vertical axis of the burner head, means for actuating said collecting mechanism from said clipper ring mounting lever, a drive shaft receiving its power from the stoker prime mover, and means driven by the drive shaft for rocking the clipper ring.

9. Ashremoval equipment for underfeed stok breaking off ash projecting beyond the said margin, ash collecting mechanism, including a ring having wedge shaped ash engaging teeth, mounted for oscillatory movement about the burner head, means for connecting said clipper ring mounting lever to said ash collecting ring to cause rocking of said clipper ring to effect oscillation of said collecting ring, a drive shaft receiving its power from the stoker prime mover, and a rank and pitman connection between the drive shaft and the clipper ring.

10. Ash removal equipment for underfeed stokers including a burner head through which the coal is fed upwardly, comprising a clipper ring, a mounting lever rockably supporting the clipper ring adjacent the margin of the burner head for breaking off ash projecting beyond said margin, ash collecting mechanism, including a ring having ash engaging teeth, mounted for movement about the vertical axis of the burner head, a pawl pivotally carried by the clipper ring mounting lever and engageable with the teeth of the collecting ring for effecting step-by-step rotation of the collecting ring, a drive shaft receiving its power from the stoker prime mover, and means driven by the drive shaft for rocking the clipper ring.

11. Ash removal equipment for underfeed stokers comprising a burner head through which the coal is fed upwardly, a horizontal drive shaft receiving its power from the prime mover of the stoker and extending to a point closely adjacent the burner head, an ash tube extending from a point adjacent the burner head end of the drive shaft to an elevated point of discharge, said ash tube being inclined with respect to and diverging laterally of the horizontal drive shaft, a screw conveyor arranged in said tube and projecting beyond the burner head ends of both the horizontal drive shaft and'the tube, the inclined and laterally diverging arrangement of the ash tube resulting in placing the projecting and unconfined end portion of the screw conveyor below the burner head end of the drive shaft and close to the burner head so as to pick up ash from adjacent the burner head and carry it into and through the tube, a countershaft extending in parallelism with the ash tube from the discharge end of the latter to a point adjacent an intermediate portion of the drive shaft, a drive connection between the upper end of the countershaft and the screw conveyor, a drive connection between the lower end of .the co'untershaft and the said adjacent, intermediate portion'of the drive shaft, mechanism associated with the burner head for breaking off the ash and delivering it to the projecting, unconfined lower end portion-of the screw conveyor, and means for driving said mechanism from the burner head end of the drive shaft.

12. Ash removal equipment for underfeed stokers comprising a burner head through which the coal is fed upwardly, a horizontal drive shaft receiving its power from the prime mover of the ascrew conveyor arranged in said tube and pro jecting beyond the burner head end thereof and beyond and below the burner head end of the horizontal drive shaft so as to pick up ash from adjacent the burner head base,'a countershaft extending in parallelism with the ash tube, a drive connection between the upper ends of the countershaft and the screw conveyor, a drive connection between the lower end of the countershaft and an adjacent, intermediate portion of the drive shaft, a casing for enclosing the last mentioned drive connection, means for supportmg the ash tube and the said drive connection casing from the burner head, means for supporting the end of the drive shaft from the burner head, mechanism associated with the burner head for breaking of? the ash and delivering it to the projecting end portion of the screw conveyor, and'means for driving said mechanism from the burner head-supported end of the drive shaft.

ROBERT W. SUMAN.

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