US2333426A - Solid fuel stoker - Google Patents

Description

Nov. 2, 19430 W. C. JOLLY SOLID FUEL STOKER 3 Sheets-Sheet 1 1 Filed March 18, 1940 JNI/EN 7'01? MLL/AM C JOLL);

A47 TOP/V5 rs Nov. 2, 194-3, w. c. JOLLY 2,333,425

SOLID FUEL STOKER Filed March 18, 1940 3 Sheets-Sheet 2 JA/l/EN TOP g ML 1. MM C. Jam 5 m ,5?

- TTO/P/VEKS- Nov. 2, 1943. w. c. JOLLY 2,333,426

SOLID FUEL STOKER Filed March 18, 1940 5 Sheets-Sheet 3 JA L EN TOP MAL/AM C J04; K

fly W M /9 E Jr TOP/V6 r5 Patented Nov. 2, 1943' UNITED STATES PATENT OFFICE soup FUEL STOKER William C. Jolly, Indianapolis, Ind. Application March 18, 1940, Serial No. 324,490

3 Claims.

This invention relates to a stoker for feeding solid fuel to a furnace in accordance with demand therefor to support combustion and it is primarily adapted to handle coke in domestic sizes. A primary object of the invention is to provide an exceedingly simple andyet highly successful means for feeding coke with the use of minimum power.

A further primary object of the invention is to provide a stoker of the type indicated which may be built and supplied to the trade at an extremely relatively low price without sacrificing in any way reliability of operation as well as durability. A still further important object of the invention is to provide means for maintaining a level of fuel bed and to maintain the level in accordance with the rate of combustion.

A still further important object of the invention is to provide a structure which may be built in a complete unit readily shiftable into position for feeding fuel to the furnace and out of that position to permit ready access to the fire box or chamber. Not only is the structure em bodying the invention built to feed the fuel to the furnace but it is also built to shake ashes from the combusion chamber at substantially the same rate as they are formed. In the form of the invention herein shown the ash shaking mechanism is adapted to connect with the usual grate bar shaker without change.

These and many other objects and advantages of th invention, including the unique combinations of elements to accomplish those objects and advantages, will become apparent to those versed in the art in the following description of one particular form of the invention as illustrated in the accompanying drawings, in which Fig. l is a side elevation in partial section of a structure embodying the invention;

Fig. 2, a detail on an enlarged scale in top plan view of the discharge end of the stoker;

Fig. 3 a detail in side elevation of the discharge end of the stoker of the opposite side from that shown in Fig. l; and

Fig. 4, a front elevation of the stoker.

Like characters of reference indicate like parts throughout the several views in the drawings.

Th fuel to be fed, coke being taken as the fuel in the present example, is placed in the hopper ID from which it is fed to drop onto a conveyor belt H by a structure not forming a part of the present invention but covered in my U. S. Letters Patent No. 2,299,394, issued October 20, 1942. In any event, the coke is carried upwardly on the top side of the belt l I which, as indicated in Fig. 1, is set upon an incline throughout its major length to have a short horizontal length at its upper discharging end. An electric motor i2 is provided to drive the belt through suitable speed reducing means, such as the belt l3 to the pulley t4, the chain it to the shaft l6, and a. worm gear drive to the pulley M, Fig. 3, around which the belt is carried.

The hopper l0, belt H, and motor l2 are, as indicated, carried by a suitable framework, generally designated by the numeral l8, and this framework is preferably mounted on casters l9 so that the entire stoker assembly is portable and may be rolled about on the floor with ease. The horizontal extension of the belt I! is within an extending box 20 which is secured to the front side of the framework l8.

Within the box 20 mounted transversely thereacross on the shaft 2| is a distributing roller 22, the upper side of which is at a lower elevation than is the top side of the belt I I, the roller 22 being mounted forwardly of the end of the belt H, as best indicated in Figs. 2 and 3. This roller 22 is driven from the shaft l6 through suitable gears, such as spiral gears 23 and 24, the important feature being that the roller 22 is revolved at a much higher rate of speed than is the pulley ll about which the belt II is carried. The upper side of the belt H is moved to travel in a direction toward the roller 22, Fig. 3, and the roller 22 is turned in a clockwise direction.

Forwardly of the roller 22 is fixed a downwardly inclined floor 25 which extends outwardly beyond the box 20. Preferably this floor 25 is provided with side walls 26 and 21 so as to form in effect a chute through which the coke must travel to be discharged from the stoker.

The upper end of the floor 25 is located to be below the top of the roller 22. Coke being brought up on the belt II is discharged from the forward end thereof and in order to prevent that coke from dropping between the belt II and the roller 22, a short length of floor 28 is interposed therebetween in an inclined manner so that the coke may slide down over this floor section 28 into contact with the rapidly revolving roller 22. This roller 22 is provided with a plurality of transversely arranged ribs 29, these ribs departing from parallel relation with the axis of the roller 22 somewhat to form broad V-like faces with the apex of the V in the central portion of the roller as best indicated in Fig. 2.

When the coke strikes these ribs 29, the coke will be given a decided impetus forwardly and in a direction depending upon what part of the rib strikes the particle of coke. In other words since the forward face of each rib 29 is non-parallel with the roller axis, the coke will be thrown to either side of the longitudinal center line of the floor 25, coke coming on one side of the roller being thrown diagonally across the floor 25 toward the opposite side of the roller 22 but forwardly thereof, particles of coke striking the center of the roller being, of course, normally directed stright ahead. Th box 20 is provided with a furnace door flange 3ILextending therearound and so located longitudinally of the box as to properly present and locate the forward end of the floor 25 within the combustion chamber of a furnace geenrally designated by the numeral 3|, the box 20 being of such dimensions as will permit its insertion through the doorway of the furnace to carry the floor 25 and its side walls 24 and 21 into the combustion chamber of the furnace. However, this extension of the floor 25 into that chamber is limited and is only carried therein a sufllcient distance as to permit regulation of the feeding of the coke in accordance with the depth of the fire bed.

Hanging freely from the top forward portion of each of the side walls 26 and 21 are the bars 32 and 33 respectively, consisting in the present form of iron bars pivoted by their upper ends to those walls to swing freely along their sides. The lower ends of these bars 32 and 33 are tied together in a fixed manner by a plate 34 which is inclined downwardly and forwardly and is positioned below the plane of the floor 25 so that the plate 34 is free to rock forwardly and rearwardly under the forward lip 35 of the floor 25, Fig. 2. As a counterbalance to some extent the plate 34 is extended rearwardly a short .distance back of the bars 32 and 33 and inclined downwardly and rearwardly to form the plate portion 36, Fig. 3. A connecting rod 31 is rockably attached to one of the bars, herein shown as the bar 33, and is carried rearwardly along the outer side of the box 20 to rockably connect with a rocker arm 38 carrying a mercury tube switch 39 on the side of the box 20. Thus as the plate 34 may be swung forwardly and rearwardly the mercury switch 39 is rocked accordingly. The mercury switch 39 is placed in the power line leading to the motor I 2 so that when this switch 38 is rocked to its open position, no current can be supplied to the motor I2 but when the switch is rocked to the closed portion, the motor I2 is immediately energized and sets into motion the feed belt II and the distributing roller 22.

In order to close off a passageway through the box 20 above the fioor 25, the front end of the box 20 being closed below that floor 25, a door 40 is swung within the box 20 near its upper end on a shaft 4|, the door being overbalanced so that it will normally drop to a closed position, as indicated in Fig. 3, by reason of its own weight. As indicated in Fig. 3, the upper end of the door 40 is in close proximity to the forward end of the top wall of the box 20 while the lower edge of the door 40 rests directly on the floor 25. The side edges of the door 40 are in close proximity with the side walls of the box 20, although the door is free to be lifted and to drop by its own weight to the closed position.

On the right-hand side of the box 20, in the present form of the invention, is mounted a solenoid magnet 42 to the armature 43 of which is attached the rod 44 that is pivotally connected with the arm 45 fixed to the shaft 4| on which the door 40 is itself fixed. 'The solenoid 42 I: so arranged that when its winding is energized the armature 43 will be pushed forwardly to open the door 40 and the door 40 will thus be maintained in that open position only as long as the magnet 42 is energized. The winding of the magnet 42 is so arranged in the power supply circuit that it is under control of the switch 39 and, therefore, is energized only when the motor I2 is energized.

In order to prevent the door 40 from dropping immediately upon de-energization of the magnet 42 and while the distributor roller 22 and the belt I I may be coasting to a stop, a time delay means is provided eifective immediately upon tendency of the door 40 to drop following deenergization of the magnet 42. In the present form, this time delay means consists of a piston 46 operating within a cylinder 41 against air or liquid therein slowly expelling the resisting medium through a small orifice, all in the usual manner of piston check structure. The piston 46 is interconnected with the armature 43 through suitable linkage, as indicated in Fig. 3. The cylinder 41 is arranged to have a sufficiently large opening at the rear end as will permit the armature 43 to travel forwardly rapidly without any great interference or resistance set up by the piston 45.

In use, the usual furnace door is removed and the stoker is rolled up to the furnace 3| to have the forward end of the box 20 and its extending floor 25 entered through the door opening to have the box encircling flange 30 brought up against the door frame preferably with asealing gasket 48 therebetween and fixed in that position by any suitable means, one particular means being illustrated in Fig. 2 as consisting of an external lever 49 on each side fixed to a shaft 50 extending through the flange 30 and carrying a cam 5| on the inside to engage behind an extending flange ear 52. In any event the stoker is thus aligned with the furnace to have the discharge end thereof entering into the combustion chamber.

As long as the plate 34 is hanging free and not rocked, the switch 39 is in the closed circuit position and the motor I2 causes the coke to be carried on the belt II and thrown into the furnace by means of the roller 22 as above explained. When the fire bed builds up sufllciently high within the fire box of the furnace, coke will eventually roll back against the plate 34 in increasing quantities and thereby push it back under the floor 25. This travel of the plate 34 causes the switch 39 to be rocked to its open circuit position to stop the feeding of the coke. The door 40 drops to close off admission of air into the furnace so that combustion in the furnace is then supported by air entering in the usual manner, such as by the draft door 53, Fig. 1. As the coke is burned, the fire bed will naturally drop and thereby allow the plate 34 to swing forwardly to close the switch 39 again to set up feeding of the coke to replinish the fuel bed and restore it to its normal depth.

This action will continue repeatedly as long as the fire bed is lowered and raised a indicated. However, it is necessary to remove the ashes from time to time, otherwise the ashes will build up until there is not suflicient room for coke to maintain combustion thereof. As above indicated, in the present form of the invention, means for operating the usual grate shaking mechanism is supplied by the stoker. The furnace 3| carries the usual external grate shaker lever 64 having a shaker bar 55 entering the furnace and connected to the grate bars in the customary manner (not shown). Suitable connections are made between the shaker bar 56 and the motor l2 to recpirocate the shaker bar 56 at all periods Of feeding coke into the furnace. These connections are so arranged and proportioned as to limit the travel of the shaker bar 56 within that range whereby the ashes are shaken out only in approximately the same rate as they are formed so that the burning coke itself is not shaken down to the grate bars but in the most desirable method a thin layer of ashes is allowed to remain over the grate bars without increasing the thickness of that layer.

The connections between the motor drive and the shaker bar 54, in the present form of the invention, consist of a jackshaft 56 which carries the pulley M; a crank 51 on the forward end of the shaft 56; a connecting rod 58 connected to the pin of the crank 51 by one end and extending across to a pulley crank lever 59 mounted to swing on a vertical pin 60; and a link 6| extending from the other arm of the pulley crank 59 to the shaker bar 54. Thus when the shaft 56 is being turned by the motor i2, the crank 51 rocks the pulley crank 59 and thereby reciprocates the shaker bar 54. Of course, the degree of travel of the shaker bar -54 i determined by the lengths of the arms of the bell crank 59 or by the throw of the crank 51 or both. In any event this simple expedient operates very successfully to shake the ashes without having to install complicated grate bars or grate bar operating means internally of the furnace, a further advantage of the stoker being that it may be applied to the usual furnace in most cases without any radical changes in the furnace itself and in fact by simply removing the furnace fire box door and then connecting the shaker bar 54 with the shaking connections above described.

Of course, when ashes are to be removed from the ash pit, the stoker may be disconnected from the furnace by releasing the latching levers 49 and pulling out the pin 62 that interconnects the link 6| with the shaker bar 54 and then the stoker may be pulled away from the furnace to give plenty of room. Where automatic ash removing means is employed, even this disconnecting from the furnace, as simple as it is, is not required.

As is apparent from the foregoing description, the coke will-continue to be fed into the furnace to maintain a definite thickness of fire bed as demanded by change in thickness thereof. In order to control the amount of heat delivered by the furnace and thereby in turn control the rate of change in thickness of the fuel bed, it is necessary to incorporate some means for controlling the opening and closing or the draft door 53. This may be done in any one of the several ways now commercially used. A very satisfactory method is to employ the usual room thermostat 63 and the commercially obtainable damper control motor 64 that carries an operating arm 65 from which a chain or cable 66 drops down to connect with the door 53. As indicated in Fig. 1, the room thermostat may operate between two terminals 6'! and 68 in the usual manner to control direction of operation of the motor 64 and thereby cause the arm 65 to lift or lower in ac-- cordance with the position of the thermostat 63. In other words the motor 64 is a reversing type motor of the usual construction employed for this purpose.

By the addition of this damper control, a very simple and yet a most effective control of stoker operation is had, all in accordance with the demand for heat in the space to-be heated. Thus upon call for heat in that space, the thermostat 63 shifts to the proper terminal to close a circuit, here shown as leading from a transformer 66 interconnected with the usual household service line, to cause-the motor 64 to operate and lift the arm 65 and thereby admit air to the furnace to increase the rate of combustion of the fuel therein. Of course, the greater demand for heat, the longer the thermostat 63 will remain in the position indicated to keep the draft door 53 open and as the coke is consumed, more coke is added automatically thereto until that demand for heat is satisfied; the door 53 closes and the fuel bed is built up to its maximum depth. The low fire condition is maintained even though the door 53 be closed by coke being added only as required by drop in elevation of the fuel bed.

While I have herein shown and described my invention in the one particular form, it is obvious that structural changes may be employed without departing from the spirit of the invention and I, therefore, do not desire to be limited to that precise form beyond the limitations as may be imposed by the following claims.

I claim:

1. In a solid fuel stoker for a furnace, a discharge box arranged to open through the fire box door of the furnace, a conveyor belt entering the discharge box, a floor in said box extending forwardly of the discharge end of the belt and having a transverse slot thereacross ahead of the belt, a fuel distributor roll positioned on an axis transversely of and below the floor to have the upper side only of the roll enter said slot, means for driving the belt and the roll in the same direction, said means driving the roll at a greater speed than that of the belt, whereby fuel particles coming from the belt onto the roll are thrown by the roll from said discharge box, a draft cut-off door hinged to swing across said discharge box forwardly of said roll to close against said floor, a fuel bed level controlling member hinged to swing freely directly under the discharge end of said box to have all of said fuel particles pass thereover, a motor for operating said driving means, a switch normally closed and controlling operation of the motor. means interconnecting said level controlling member and said switch operating to open the switch upon being rocked a predetermined position toward said box, electro-magnetic means in circuit with said switch operating said draft door to an open position when energized upon closed switch condition.

2. In a solid fuel stoker for a furnace, a discharge box arranged to open through the fire box door of the furnace, a conveyor belt entering the discharge box, a floor in said box extending forwardly of the discharge end of the belt and having a transverse slot thereacross ahead of the belt, a fuel distributor roll positioned on an axis transversely of and below the'floor to have the upper side only of the roll enter said slot, means for driving the belt and the roll in the same direction, said means driving the roll at a greater speed than that of the belt, where by fuel particles coming from the belt onto the roll are thrown by the roll from said discharge box, a draft cut-off door hinged to swing across said discharge box forwardly of said roll to close against said floor, a fuel bed level controlling member hinged to swing freely directly under the discharge end of said box to have all of said fuel particles pass thereover, a motor for operating said driving means, a switch normally closed and controlling operation of the motor, means interconnecting said level controlling member and said switch operating to open the switch upon being rocked a predetermined position toward said box, electro-magnetic means in circuit with said switch operating said draft door to an open position when energized upon closed switch condition, and time delay means holding said door open for an interval of time following opening of said switch.

3. For a furnace having a fire box, a fire box door opening, and a stoker, a stoker fuel feed chute formed to enter through said door opening to terminate by an end within and over said fire box adjacent the side thereof at said door .opening, a plate rockably supported by said and to be adjacent one side of said fire box away from the zone therein in which fuel from the stoker is initially deposited, stoker control means, and connecting means between said plate and said control means actuated in response to a predetermined lateral movement of fuel in said flre box against said plate causing movement of the plate toward the wall of the tire box, whereby said control means may be actuated in accordance with the depth of fuel in the flre box. said plate being free to swing back substantially horizontally to its normal position when said fuel drops therebelow.

WILLIAM C. JOLLY.

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