US2136807A - Side retort stoker - Google Patents

Description

Nov 15, 1938. J; 5. SKELLY SIDE RETORT STOKER '3 Sheets-Sheet I Filed Dec. 17, 1934 SLEQ/ENTOR Nov. 15, 1938. J. s. SKELLY SIDE RETORT STOKER Filed Dec. 17, 1934 3 SheetsrSheet 2 INVENTOR Novow, 1938. J. s. SKELLY SIDE RETORT STOKER Filed Dec. 17, 1934 3 Sheets-Sheet 3 atented Nov. 15, 1938 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to underfeed stokers and more particularly to underfeed stokers of the side retort type.

In underfeed stokers having a single horizontal retort positioned adjacent a side wall of a furnace [with an ash receiving grate at one side only of the retort andtuyere blocks spanning the space between the retort and the ash receiving grates, there is a marked tendency for the fuel to m the adjacent furnace side well.

While a side retort stoker requires fewer parts, is somewhat simpler to operate than a center retort stoker and allows the ash to be taken out at one point instead of two (as in the center retort stoker) this cumulative piling up of the fuel has been found to be a marked disadvantage of the side retort type and an object of this invention is to produce a side retort stoker which, while simple in construction, overcomes this piling up tendency of thefuel.

I have found that this tendency of the fuel to pile up above the retort in side retort stokers can be effectively overcome if certain of the tuyere blocks between the retort and the ash receiving grates are caused to reciprocate toward and ,from the retort in the proper amount to cause fuel to move toward the ash receiving grate at the desired rate of speed, and another object of this invention is to produce a simple, rugged, adjustable means for reciprocating these tuyere blocks.

I find that for a given furnace area, that is, for given dimensions within a furnace fire box and with the same retort dimensions, I am able to effectively burn more fuel on a side retort stoker than on a central retort stoker.

Stokers embodying this invention are particularly adapted for sizes from 25-200 H. P. and are particularly suitable for installations in places such as school buildings, apartment houses, office buildings, green houses and the like where it is not usual to employ skilled operators as in larger installations.

After much experimental work on single retort stokers and particularly those of the side retort type, I have found that a screw conveyor is the most satisfactory feeding device for a wide variety of fuels and I have also found that in addition to the reciprocating tuyere blocks on one side of the retort for overcoming the piling up tendency above the retort it is most essential to incorporate, in the unit, means for distributing and agitating the fuel within and above the re- 5| tort and an object of this invention is to produce cumulatively pile up above the retort'and against means operable from a single power shaft for operating in a coordinated manner the screw conveyor, the reciprocating tuyere blocks and the distributing and agitating means within the retort.

I find that it is necessary to so correlate and 5 coordinate these different agencies that each contributes its share to the proper distribution of the fuel, that is, the fuel conveyed to the retort, the fuel within and immediately above the retort m and the fuel burning surfaces between the retort and the ash receiving grate and another object of this invention has been to produce means whereby these different agencies can be properly correlated and coordinated to produce a stoker 1 5 which will effectively burn slack, as well as a wide variety of other fuels.

I also find that it is necessary to vary the air feed to different parts of the fuel bed and a still further object is to provide simple means for allocating air under pressure to different parts of the fuel bed in a side retort stoker in the proper amounts to support combustion without blasting portions of the bed, blowing cold spots in other portions or holes in other portions.

These as well as other objects, which will readily appear to those skilled in this particular art, I attain by means of the stoker unit described in the specification and illustrated in the drawings accompanying and forming part of this application.

In the drawings:

Figure 1 is a view partially in side elevation and partially in section (and with some parts broken away), of a side retort underfeed stoker embodying this invention. This view shows some of the tuyere blocks as well as a portion of the retort side wall on the ash grate side of the stoker broken away;

Fig. 2 is a top plan view of portions of t e stoker illustrated in Fig. 1 with certain of the tuyere'blocks removed. The fuel feeding mechanism, the fuel reservoir or hopper and associated. parts have been omitted and a portion of the ash supporting grates has been broken away;

Fig. 3 is an enlarged view in section, more or Fig. 4 is an enlarged detail view in side elevation of one of the stationary tuyere blocks located between the retort and the ash grates. This view shows its position with relation to the rock shaft for reciprocating the movable tuyere blocks;

Fig. 5 is a detail view partially in section and partially in end elevation of the rock shaft and part of its operating mechanism;

Fig. 6 is a view partially in section and partially in elevation of the parts shown in the central portion of Fig. 3, viz., the tuyere blocks, the rock shaft and part of its operating mechanism, a part of one retort side wall and a part of the wind box wall. This view shows the position of the movable tuyere block at the end of its movement away from the retort.

Fig. '7 is a top plan view of part of the mechanism shown in Fig. 6;

Fig. 8 is an enlarged detail view in end elevation of one of the support members for one of the bearings for the rock shaft. This view includes part of the mechanism for operating the rock shaft; and

Fig, 9 is a view in side elevation of the tuyere block shown in Fig. 4, but taken from the other side and turned end for end.

In the stoker I have chosen for the purpose of illustrating my invention, the retort I is U- shaped in transverse section as shown in Fig. 3 and is elongated (Fig. 2) and provided with a sloping inner end wall II. The top surrounding edge of the retort is provided with an outwardlyextending flange I2 and the retort is provided with support legs l3 which rest upon the floor i4 of the wind box. Upright wall I 5 of the wind box is spaced away from the retort to provide an air channel for supplying tuyere blocks IS with air under pressure. The upper edge of side wall l5 of the wind box is provided with an inwardly extending lip or flange i! which cooperates with flange l2 of the adjacent retort side to support the tuyere blocks.

Side wall l5 of the wind box is adapted to lie against one side wall ii of the furnace within which the stoker is installed. Tuyere blocks l6 fill the space between wall l8 of the furnace and the inner adjacent edge of the retort. These tuyere blocks have their inner surfaces l9 curved and each block is preferably provided with a number of air discharge channels for directing air under wind box pressure to the fuel lying above the retort.

Each of these tuyere blocks has a central partition 2l'which extends downwardly below the I body of the block and terminates in a T-shaped end 22 which cooperates with flanges I2 and H to lock the tuyere block against upward movement.

Side wall 23 of the wind box is provided with an inwardly extending flange 24 along its upper edge and this wall is spaced away from its side of the retort a suflicient distance to accommodate relatively long tuyre blocks 25 and 26.

Tuyere blocks 25 (see Figs. 3, 3a, 3b, 6 and 9) areprovided with one flat side 21 and certain of these blocks 25 are made as rights while certain of them are made as lefts, that is, cer

tain of the blocks have projecting ledges or supports 28 and 29 which extend outwardly in one direction from the flat side 21 while certain others have corresponding ledges projecting in the opposite direction from their flat side 21. This is clearly shown in the right half portion of Figure 1 in which alternate stationary tuyere blocks beginning at the right-hand side of Figure l have their flanges 26 and 29 extending toward the left while the other stationary tuyere blocks have their flanges 28 and 29 extending toward the right. This is also clearly shown in Fig. 3b. Below each such ledge portion the block is provided with a downwardly extending narrow hook-like member; that below ledge 28 is numbered 30 and that below ledge 29 is numbered 3|. These hooklike members are adapted to hook under flanges i2 and 24 respectively, and lock these stationary tuyere blocks 25 against upward movement.

The upper surface of each of the flanges 28 and 29 is smooth and flat and forms a bearing surface upon which tuyere blocks 26 are supported for reciprocation within the channel formed by a pair of stationary tuyere blocks 25 as shown in Figs. 2, 3b and 6.

Approximately midway between the ends of each of the tuyere blocks 25 and projecting laterally from the side opposite its flat side a vertical partition 32 extends from the roof or fuel supporting portion thereof to a sealing flange 33 located at the bottom of the central partition 21. This sealing flange extends across the tuyere block for the full width thereof. Thelower curved surface 34 of each of the sealing flanges is formed on the arc of a circle for a purpose to be hereinafter described. Partition 32 is provided with an air discharge passage 35. The upper or fuel supporting surface of each of the tuyere blocks 25 is provided with a series of air channels 36 between flange 29 and partition 32 and the fuel supporting surface between partition 32 and flange 28 is provided with a series of air discharge channels 31 and another series 38. Channels 38 direct air into the fuel bed above the retort.

Extending outwardly from the flat side of each stationary tuyere block 25 are lugs or flanges 39 and 40 for a purpose as hereinafter set forth. Each of the movable tuyere blocks 26 is provided with a central partition or wall 4| and on each side of this wall is provided with a vertically extending rib 42. These ribs at their lower ends join an inverted U-shaped or bifurcated member 43 which extends across the block and forms its lower extremity serves as means for connecting the tuyere block to the projecting flange of the rock shaft to be'described later. The rock shaft causes the movable tuyre blocks to reciprocate as it is oscillated.

Horizontal shelves 44 extend laterally from central rib 42 on opposite sides of central partition 4i and central partition 4| extends downwardly on each side of the inverted U-shaped member 43. Each of the movable tuyere blocks 26 is provided with a series of air channels 45 for projecting air directly into the fuel above the retort; a series of air directing channels 46 for directing airinto the fuel above the retort and also to that portion of the fuel bed supported by the inner portions of the tuyre blocks and these tuyere blocks also have a series of air discharge channels 41 for discharging air into the shallower portion of the fuel bed above the tuyere blocks. Lugs or flanges 39 and 40 which project laterally from the flat side of each tuyere block 25 retain the movable tuyere blocks in place on supporting flanges 28 and 29 of tuyere blocks 25. Flanges 39 lie aboveflanges 44 of tuyere blocks 26 and flanges 4!! lie above laterally projecting bottom flanges 48 of tuyere blocks 26 as clearly shown in FigureBb.

.The stoker unit of this invention is preferably operated by a variable speed driving mechanism such asdisclosed in my application which is serially numbered 706,040. As in said application, the blower for supplying the wind box with air under pressure is directly coupled to the motor which drives the variable speed mechanism. The variable speed mechanism is provided with a power shaft (Figure 1) and this shaft by means of a suitable coupling, is connected to a shaft 5I of conveyor screw 52.

The inlet end of the feed screw is that portion located below the outlet of the hopper-like fuel storage magazine 53. The outlet of the magazine is controlled by means of a slide 54 which acts as a gate for stopping the flow of fuel from the magazine to the inlet end of the feed screw.

The feed screw is located within a tubular housing 55 which passes through the end wall 56 of the retort I0. rounds housing 55 and serves as a conduit for conducting air under pressure delivered by the blower to the wind box whichsurrounds the retort.

A rock shaft 58 which is circular in transverse section in the main, is provided with an upwardly extending flange 59 which extends throughout its length, except at its extreme end portions. This shaft is mounted below the stationary and movable tuyre blocks 25 and 26 and within the space between the side wall 23 of the wind box and the adjacent side of the retort I0. The rock shaft parallels the wind box side 23 and the retort side and at its rear end is mounted in a bearing block 60 secured to the rear end Wall GI of the wind box. At its front end this shaft is journaled in a bearing 62 formed in a block 63 bolted to front wall 04 of the wind box. This latter bearing as shown in Fig. 8, has an open top so that the shaft, after having its rear end entered in bearing 60 can be lowered into place with the front end cylindrical portion 58 entering the bearing 62 which cylindrical portion is held in position by cap member 65 which in turn is held in place by a bar 66.

Upstanding flange 59 on the rock shaft extends into inverted U-shaped members 43 on the movable tuyre blocks and as the shaft is oscillated, the top of this flange describes the arc of a circle which lies close to the curved undersurfaces 34 of sealing flanges 33 on the stationary tuyre blocks 25.

The rock shaft adjacent its forward end and just behind its bearing 62 is provided with a projecting arm 61. This arm is drilled at its center to form concentric bores of two diameters. The larger bore is tapped to receive the threaded portion 59 of a pin 68 and the smaller portion Ill snugly fits the inner smaller bore. That portion of the pin which projects beyond the outer end of stub shaft 61 carries a bearing ball II which is held in place by means of the head I2 of pin 68.

Block 63 is provided with a partially cylindrical portion I3 which extends laterally therefrom and is drilled to receive a stub shaft I4 and on this, the hub 15 of a bell crank lever is mounted. The upper arm 16 of this lever is provided at its forward end with a box-like portion, I'I which has a rectangular opening within which ball TI is located. The other arm I8 of the bell crank lever projects downwardly and has its lower end I9 bifurcated as shown in Figs. 5 and 8. This bifurcated end is coupled by a coupling device to a connecting rod which is mounted for longitudinal reciprocation toward and from the retort. The coupling device comprises a link 8| connected by means of a pin 82 to arm I8 and Another housing 5'! sur- .the stationary tuyre blocks has its forward end drilled and tapped to receive a screw threaded stem 83 of a lost motion connectlng member 04. This member 84 is provided with an elongated slot 85 into which extends a pini 86 carried at the inner end of the connecting r0 Connecting rod 80 adjacent its rear end carries a laterally extending pin 86 which lies within slot 85. Surrounding pin 86 between member 84 and a plate 81 bolted to the side of the connecting rod is a tubular spacer 88. This serves to space lost motion member 84 from plate 81.

By placing take-up liners (not shown) within slot 85 of lost motion member 84, the amount of lost motion between connecting rod 80 and arm I8 of the bell crank lever may be adjusted. In this way just the right amount of travel of the reciprocating tuyere blocks 26 is obtained. The forward end of connecting rod 80 carries a vertically extending pin 89 and upon this a tapered cam follower or roller 90 is mounted. This tapered roller is positioned within a continuous groove 9| formed in the periphery of a cam wheel 92. The continuous groove 9! has flared sides corresponding to the taper of cam follower 90. The clearance between the follower and the flared sides is such that the follower may run freely within the groove without binding.

Groove M is disposed at an angle to the plane that is perpendicular to the axis of'shaft 50 so that as the cam wheel is rotated, connecting rod 80 will be given a back and forth longitudinal reciprocation. I

The fuel agitator located within the retort and which not only agitates the fuel within the retort and that above the same, but also distributes the fuel so as to form a homogeneous mass, comprises a reciprocating bar 93 which is supported at the front and rear ends of the retort by wear plates respectively numbered 94 and 95. This bar on its upper surfaces carries agitating and distributing members 95 and 91. The forward end of bar 93 by means of connecting plates 81 and 98 and suitable bolts as shown in Figs. 1, 6 and 7 is coupled to connecting rod 80.

Reciprocating bar 93 passes through an opening 99 formed for that purpose in slopingend wall II of the .retort.

The ash receiving and disposal grates I00 may be of any desired design or construction so long as they are of adequate size and design to support the ash between periods of dumping.

Sealing flanges 33 on the stationary tuyre blocks 25 as I have said, lie in close proximity to the top of longitudinal flange 59 on rock bar 58 and these flanges are sufliciently long from front to rear to cover the full movement of flange 59 on the rock bar. These flanges, together with members 43 on the movable tuyere blocks which straddle flange 59 of the rock bar and a sheet metal partition plate IOI which extends from side 23 of the wind box to a point I02 which is beyond the center of the rock bar prevents Wind box air from reaching air channels 41 of the movable tuyre blocks 26 and air channels 36 of 25, except by way of ports 35 in partitions 32 of the stationary tuyre blocks 25 and openings I03 in ribs 42 of the movable tuyre blocks 26.

Partition plate IOI is held in position and in contact with the cylindrical under surface of the rock bar during its oscillation by means of a spring member I04 which is secured to the wind box side and bears against plate I 0|.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an underfeed stoker, an elongated horizontal retort, tuyere blocks on opposite sides thereof and of which at least some on one side 7 are mounted for reciprocation toward and from.

the retort, a screw conveyor for feeding fuel into the retort, a fuel feeder and agitator mounted for reciprocation within and longitudinally of the retort, a rock shaft having operative connection with the movable tuyere blocks, a power shaft for rotating the screw conveyor, a cam wheel carried by said shaft, a connecting rod operated by said cam wheel for reciprocating said fuel feeder and agitator and agents between said rock'shaft and connecting rod for oscillating said shaft.

2. In an underfeed stoker, a horizontal retort, tuyre blocks on opposite sides of the retort with certain of the same on at least one side thereof mounted for reciprocation toward and from the retort, a screw conveyor for feeding fuel into the retort, a rotatable power shaft to which said conveyor is coupled, an agitator and fuel feeder mounted for reciprocation within and longitudinally of the retort adiacent its bottom, a cam wheel carried by said power shaft, a connecting rod reciprocated by said cam wheel and coupled to said agitator and fuel feeder and means also coupled to said connecting rod for oscillating said rock shaft.

3. In an underfeed stoker, an elongated horizontal retort, tuyere blocks on at least one side thereof and some of which are mounted for reciprocation toward and from the retort, ascrew conveyor for feeding fuel into the retort, a fuel feeder and agitator mounted for reciprocation within and longitudinally of the retort, a rock shaft having operable connection with the movable tuvere blocks, a power shaft for rotating the screw conveyor, a cam wheel carried by said shaft, a connecting rod operated by said cam wheel for reciprocating said power feeder and agitator and agents between said rock shaft and connecting rod for oscillating said shaft.

4. In an underfeed stoker, a horizontal retort,

-tuyere blocks on at least one side of the retort with certain of the same mounted for reciprocation toward and from the retort, a screw conveyor for feeding fuel into the retort, a rotatable power shaft to which said conveyor is coupled, an agitator and fuel feeder mounted for reciprocation within and longitudinally of the retort adjacent its bottom, a cam wheel carried by said power shaft, a connecting rod reciprocated by said cam wheel and coupled to said agitator and fuel feeder and means also coupled to said connecting rod for oscillating said rock shaft.

JOHN S. SKELLY

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