US2414802A - Combined stoker and furnace - Google Patents

Description

Jan. 28, 1947. Q H, @Usl-UNG 2,414,802

l COMBINED STOKER AND FURNACE Filed June 22, 1944 4 sheets-sheet 1 E. f/ @n IN V EN TOR. George H. Cus/Jing Jamv 28, 1947. G. H. cusHlNG 2,414,802

COMBINED STOKER AND FURNACE Filed June 22, 1944 sheets-sheet s Fig. .3

. INVENTOR. Geo/je H. Cushing G. H. cusHlNG 2,414,802

COMBINED STOKER AND FURNACE Filed June 22. 1944 4 Sheets-Sheet 4 Jan.. 28, 1947.

n i a N C M l. Bmw/ 0 Wd fev7 l @Q l J V.. R. mm,|\ B lww @EN Qu ,y .l nu \w\\ @l M M-J.. Nm all" ""IIHHI, I...... I |$v fl Y f2 m A@ f Patented Jan. 28, 1947 UNITED STATES PATENT OFFICE commun s'roinin AND FURNACE George n. Cushing, chicago, 111. Application .l une 22, 1944, Serial No. 541,545

(o1. 11o-s2) 9 Claims. l

This invention relates to a method of and apparatus for burning hard fuel and part of the subject matter thereof has been divided from my pending application for patent on an improvement in Coal stokers and control thereof and the like, filed February 6, 1943, under Serial No. 474,937, and is a continuation in part thereof.

One of the objects of this invention is the provision of a novel method for burning hard fuel, such as the various kinds of coal, coke, etc., whereby all of the combustibles in fuel may be entirely consumed, leaving only a residue of ne ash.

Another object is the provision of a method of burning hard fuel wherein fresh charges of the fuel are charged upon a cleared section of the grate and contiguous with a previous charge which has become ignited.

Another object is the provision of a method of burning hard fuel which consists in controlling the amount of the charges of fuel, the frequency of introducing the charges upon the grate, coordinatedwith damper means to regulate the draft in accordance with the frequency of charging the furnace, whereby a substantially constant temperature may be maintained in the space or spaces heated by the furnace, regardless of the outside temperature.

Another object of this invention is to provide a side feed stoker for use in connection With a furnace or other heating apparatus for burning hard fuel in measured quantities concurrently in predetermined stages of combustion.

Another object is to provide a Stoker with automatic feed and automatic ash remover.

Another object is to provide a furnace capable of burning a great variety of sizes of solid fuel, either separately or mixed.

Another object is to provide a stoker which will free its operator from any manual attendance upon the furnace.

.Another object is to provide a simple and compartly in vertical longitudinal section taken substantially along the line 2-1-2 of Fig. l, with roller 15a shown in dotted lines to indicate its location;

Fig. 3 is an end elevation looking in the direction of the arrow 3 in Fig. 2;

Fig. Il is a perspective view of fragments of the reservoir, re box and ashv conveyor, and illustrating atrack for a certain trap door associated with the grate;

Fig. 5 is a front elevation of a control box seen in Fig. 2; A

Fig. 6 is a vertical cross section taken on the line E- of Fig. 5;

Fig. '7 is a horizontal section l'-'l lof Fig. 5;

Fig. 8 is a vertical section taken `on. the line 8-8 of Fig. '7;

Fig. 9 is a vertical section through fragments of a smoke pipe, illustrating the damper;

Fig. 10 is a plan of the damper seen in Fig. 9 with the smoke pipe shown in section;

Fig. l1 is an under plan of a fragment of one of the grate segments; and Y Fig. 12 is a wiring diagram of a time switch used for controlling the starting and stopping of the notor which operates the stoker.

Referring to said drawings, which are somewhat schematic and illustrate oneV embodiment of the invention, the reference character Il] designates the casing of a furnace or other solid fuel burning heating apparatus, in the lower end Vof Which is a low fire-brick wall II surrounded by a sheet metal retaining wall I Ia.

Mounted upon a base plate l2, which extends within and without the casing I0, is a base I3 upon which is secured a post I4 having an annular shoulder I5 upon which rests a beveled gear Wheel I6 which carries a grate composed of grate sections I1 that are desirably of segmental form and ride on a circular track I Ib carried by the retaining wall II. Also mounted on the upper end taken on the 'line i of the post I4 is an air dome I8. The grate and rire-brick wall Ila provide a lire-box: in which the fuel is consumed. The beveled gear wheel and grate are intermittently rotated in timed relation to the feeding of fuel upon Ithe grate and the means for rotating the grate may comprise the beveled gear Wheel I6 which meshes with a beveled pinion 29 mounted upon one end of a shaft 2| journaled in suitable bearings and intermittently rotated from the main drive shaft 30 of the apparatus by suitable gearing, as will be presently described.

Disposed at one side of the furnace is a fuel delivery conduit or reservoir 22 which is located therefrom toreceive Ibetween said side walls a reciprocating ram or plunger 2B which functions to intermittently feed solid fuelinto the fire-box and upon the grate and in an approximately radial direction with respect to the axis of the grate. l

The bottom Wall 21 of the reservoir projects over the edge portion of the grate and guides the Afuel thereto. The top wall of the reservoir has an opening 29 therein located above and forward of the ram, Fuel entering said opening falls upon' and in front of the ram where it lies until the ram is retracted, whereupon the fuel lying upon the ram falls into the reservoir in front of the front face of the' ram, This space in the reservoir is calculated to hold a measured quantity of fuel sufficientV for one charge besides a wall of fuel which always remains in the throat.

Any form of hopper or fuel feed may be employed to deliver fuel into the reservoir and the one illustrated will be hereinafter described.

Journaled in suitable bearing brackets ila mounted on the base plate is the main drive shaft 3B, here shown in the form of a crank shaft of which the crank 3l is connected to one end of connecting rod 32, the other end of which is connected to the ram 26 by a wrist pin 33 secured in the side walls of the ram.

Mounted on a motor base 34, which rests on andis secured to the base plate `I2, is a motor 35, desirab-ly in the form of anA electric motor, which comprises the prime mover for the apparatus. Associated with the motor is speed reducing gearing 36 which couples the motor shaft with the main drive shaft 39 and rotates the same through one or more complete revolutions during each cycle of operation of the Stoker. Mounted adjacent the speed reducing gearing is a circuit breaker or time switch 3l which breaks the circuit for the motor at the completion of each cycle of op eration.

The circuit breaker or time switch maybe of the common and well known time switches controlled by a rotating shaft to break the circuit at the conclusion of a cycle of operation,

In Fig. 12, such a time' switch 37 is shown, having a magnet 31a connected tothe control means 40, 45, by lines 43, 65a. The associated armature s'lb is connected to a movableA switch contact piece 31o by a link 31d and makes contact with a stationary `contact'piece 31e whenever the magnet is energized'as a result of one of the contact points 4| closing the circuit through the magnet` When the circuit through the conductors 3U, 31p to the motor 35 is closed by the contacts 31e and 31e, the motor is started. A latch 31h has a finger that prevents the movable contact 37e from breaking con-tact with the stationary contact 31e when the magnet 31a is rie-energized .as a result of the contact 4| running on? the contacts 45. TheV latch 31h is connected to a release lever 3h by a link, and the main drive shaft so has a pin or stud 31j thereon, which engages the lever 31a when the shaft has made one complete revolution, thereby releasing the movable contact 31e from the latch and permitting it to be swung out of contact with the stationary contact 37e, therebyv Lil.

y4 opening the circuit through the conductors 31j. 31g and stopping the motor.

The control means for controlling the frequency of charging the furnace and for controlling the damper is best seen in Figs. 5 to lo inclusive. This control means may be installed at any convenient place in the building heated by the furnace. In general, i-t comprises a. cabinet 33 in which is mounted a motor 3a, such as a clock works, upon the main drive shaft 3sat of which is removably mounted a time disc lll composed of non-conducting material and having concentric rows of contact points [l5 secured therein with their ends flush with the side faces or" the disc. The contact points are spaced equidistantly in each row 'but the number of contact points in each row increases progressively outward from the center of the disc so that with a constant rate of speed of the disc a more or less number of contact pieces will pass a given point during each hour or day.

Sl-idably guided in a vertical guideway ft2 secured to a side wall of the cabinet is a vertically movable contact carrying member i4 formed with .a forked arm l5 straddling the disc and contain-y ing two electrical conductors which `are provided with inturned lcontact fingers liladapted to make Contact with the contact points il of any row'. Means are provided for raising and lowering the contact carrying member .14 so as to position the lingers to make Contact with any given 'row of contact points, depending upon outside temperature, grade of coal, etc. The means here shown for this. purpose comprise an upright rack barlliS which extends up from the forked arm t5 and has rack teeth on one edge that mesh with a pinion i9 fast on a shaft or a spindle 56 that extends out through and is secured to a dial Eil which cooperates with a Vernier 52 secured in thefront Wall 38. A suitable bearing bracket 53 supports the shaft and a knob is fastened on its outer extremityv whereby it maybe rotated. Rotation of the shaft will raise or lower the con'- tact carrying member it through the instrumentality of the pinion and rack bar.

The contact carrying member ill also Vcoinbrols the damper 55 which is contained in the smoke pipe 56 of the furnace. lThe damper consists of ,-two substantially semi-circular damper plates 5l carried `by two parallel rods 58 which are rotatably mounted in a split ring 5e, clamped upon the two adjacent ends of two smoke pipe sections. On `one end of the rods 5S are formed crank arms 68 that cross each other and incline upwardly away from the damper plates when the latter occupy a horizontal position. Means are employed for holding the damper plates in any position of adjustment and, as shown, said means comprises a weighted body 6I which rests upon the upper extremities of the crank arms and is suspended by a cable or other flexable element 62 passing over sheaves 63, $4 and extending to the contact carrying member 415 where the cable is secured to Said member. When the Contact carrying member is lowered to increase the firing frequency it raises the weighted body 6i, pen mitting the damper plates to swing down under the force of gravity, thereby enlarging the pasM sageway between the damper plates and the smoke pipe. Y

In the operation of the control means just described, when the forked arm 5 is set to make contact with the outermost row of contacts, the weighted member 6i has been raised to the limit of its upward movement, thereby holding the damper plates in their fully open position. In this position of the contact carrying member the contact lingers are arranged to make contact with the contact points in the outermost row containing the greatest number of contacts; and as a result, the circuit to the circuit breaker or time switch is closed frequently, thereby causing frequent charging of the furnace. In milder weather the contact carrying member is raised more or less by rotating the knob 54 in a clockwise -direction thereby bringing .the forked contact carrying arm 45 into a position in which .the contact fingers contact with `one or another of the inner rows of contact points, and simultaneously the weighted body 6I is lowered thereby swinging the damper plates into `a more or less horizontal position.

The electrical conductors 65a lead from the control cabinet through the circuit breaker or time switch 31 and are suitably connected to the house current. It is to be understood that, as the disc slowly revolves with the contact carrying member set to make contact between the contact lingers and the contact points of any row, as each contact point contacts the fingers, it closes the circuit to the circuit breaker or time switch, thereby closing the circuit to the motor and setting it in motion. The circuit breaker or time switch is set to permit the motor to run for a suicient length of time to rotate the drive shaft 30 through one or more complete revolutions of 360 degrees and then break the .circuit and stop the motor.

It is to be understood that during each cycle of operation `a measured charge of fuel is charged into the fire box and upon .the grate, which charge is deposited upon the grate contiguous with the previous charge of fuel which has al ready been ignited- Each charge of fuel assumes a "pie slice form upon the grate and is ignited from the burning previously deposited charge. The grate and the fuel thereon remain stationary until the ram is being retracted, whereupon the grate is given a partial rotation whereby to present a vacant space on the grate to receive a subsequent charge to be deposited contiguous with the last charge. The means for intermittently rotating the grate will now be described.

An accepted practice when coal is fired by hand has been for years to move the live coal to one side and re the green coal on ,the vacated space. In laddition to the standard practice, I have provided clearance space between the bottom of the partition and grate to permit small amounts of coked coal to pass beneath the partition to serve as kindling. Finally the green coal impinges against the incandescent coal in the previously deposited charge and is ignited.

Mounted upon the shaft 30 is a mutilated gear wheel B which is arranged to mesh with a gear wheel 66 mounted upon a shaft 61 journaled in the bearing brackets Ma. Mounted upon shaft 61 is a beveled pinion 68 which meshes with a beveled pinion B9 mounted on the shaft 2|. The

mutilated gear wheel 65 has gear teeth upon 186 degrees of 4its face and is so related to the gear wheel 66 that when the main or crank shaft 30 begins its'cycle of rotation `and begins to project the ram 2B, the gear wheel 66, shaft 2| and grate will remain idle, and that when the crank begins to retract the ram, the first tooth of the mutilated gear wheel meshes with the gear wheel 66 and rotates it and therewith rotates the beveled pinions 68, 69, shaft 2|7 pinion 20 and gear wheel I E, thereby rotating the grate through a Rigidly secured to the side wall 24 of the reservoir is a partition or sweep 10 which extends radially over the grate to the air dome i8. The partition 10 extends down to the grate and it functions to sweep the ashes from the grate as lthey encounter the partition.

One of the grate segments is provided with a swingable trap door 1l located in a cutout portion of a grate section. The trap door has a roller 12 (see Fig. 4) which projects in a radial direction with respect to the :axis cf the g-rate and runs upon the annular track l Ib. The track is offset downwardly as at 13 to permit the trap door to swing down and allow clinkers, slate and other unconsumed pieces to discharge from the grate.

Suitable fuel feed and lash removal apparatus are provided. one form of which is shown for the .purposes of illustration.

Extending from a suitable fuel bin (not shown) is an inclined conveyor 15 which conveys fuel to the reservoir and discharges itv through the opening 29 thereof. A cover or closure 16 is provided upon the reservoir above the opening 2S. Any suitable driving means may be provided for the conveyor 15 and it is here shown as comprising a sprocket wheel 11 on the shaft 2l, `a sprocket wheel 19 on the shaft of the upper roller 15a over which the conveyor is trained, and a sprocket chain 18 .trained over said sprocket wheels.

The ash removal means, as shown, comprises a conveyor belt trained around rollers 8l, 82, 83 carried by suitable brackets. The conveyor belt 80 is disposed below and at one side of the partition or sweep 10, as shown in Fig. Land a hopper 80a is provided below the grate for guiding the ashes to the conveyor belt. ISuitable means are provided for driving the conveyor belt 80 and, as shown, said means comprise a Ibelt 85 trained around a sheave 35 on the main crank shaft and a sheave 81 on Ithe shaft of the roller 83.

Below the discharge end of the conveyor belt B is a transversely extending conveyor beltl 84 which carries the ashes away from the furnace. Driving means are provided for the conveyor belt 84 and, as shown, said means comprise a gear wheel 88 upon the shaft 2l which meshes with a pinion 89 on the shaft of the roller 90 over which the conveyor belt 84 is trained,

In the operation of the combined stoker and furnace, fuel is delivered into the fuel delivery conduit and the control means is set in accordance with the outside temperature and the switch for the electric circuit is closed.

. When one of the contacts 4l of the. control mechanism closes the circuit through the conductors 45, 65a, the circuit is then closed through the time switch and through the motor which drives the main crank shaft 3B through one complete rotation and then is stopped by the time switch. During the first half revolution of the crank shaft the grate is stationary and the plunger is moved toward the grate, thereby depositing a` charge of the fuel thereon. During the thereon in front of the discharge opening of the fuel feeding conduit.

The present method of burning solid fuels of any known but widely variable chemical composition and attendant variables comprises the segregation of a predetermined quantity of solid fuel, measured by volume, successively feeding charges of that solid fuel radially upon a cleared section of a circular and perforated grate; igniting each fresh charge of solid fuel by the application `ofheat and air from the bottom, top and side of the fuel; rot-ating the grate at predetermined intervals to the end that the coal, without being disturbed, may burn in a series of stages until combustion is complete; timing the movements of the grate so that the coal will be consumed while the grate is making one complete revolution; regulating the timing of the grate movements to permit the use, at will, of the slowest and fastest burning solid fuels or those havn ing a wide range of volatile content; providing automatic draft regulation to supply the quantity of air needed by fuelbeds of varying thickness and burned in different time periods; .and removing the ash, automatically, to close the grate to permit the free play of air upon the fuel to be burned.

The electrical controlmeans for the motor and for the damper is set in accordance with the outside temperature and the character of fuel used.

The fuel on the grate continues to burn until each charge has been consumed, leaving only a residue of ashes which encounter the partition or sweep and are swept from the grate, leaving a clear space for a fresh charge.

Having thus described my invention, it is obviousI that various immaterial modifications may be made in the same without departing from the spirit ofY my invention; hence, I do not wish to be understood as limiting myself to the exact aform, construction, arrangement and combination of parts herein shown and described, or uses mentioned,

What I `claim as new `and desire to secure by Letters Patent is:

1. In a combined furnace and stokerthe combination of a re box having a rotatable grate, a motor, intermittently operated motor starting and stopping mechanism including a circuit breaker in electrical connection with said motor,

means driven by said motor and including intermittently operated driving connections to lintermittently rotate said grate, a stationary partition extending upwardly and above said grate in a direction radial with respect thereto, said partition functioning to sweep ashes from the grate whereby to provide a clear space on the grate to receive fuel, a fuel delivery conduit having one side wall approximately aligned with said partition and forming the support for said partition, the fuel delivery conduit having 'a throat opening to said fire box, a ram in said fuel delivery conduit for charging fuel upon said grate in a direction approximately radial thereto, and a driving connection between said ram and motor for intermittently reciprocating said ram in timed relation to the rotatory movement of the grate.

2. In a combined furnace and stoker, the combination of a fire box having a rotatable gratea motor drive-n intermittently rotated crankshaft having la crank, drive gearing between said shaft and grate including an intermittently operate-d driving connection, a fuel delivery conduit having one side wall extending radially with respect to the grate and having a throat opening to the firey box above the grate, an ash sweeping partition extending upwardly and above the grate, secured to and supported by said side wall and forming a continuation of said side wall, a ram reciprocating in said fuel delivery conduit, and a connection betweensaid ram and crank of the crank shaft arranged to move the ram toward the grate when the latter is stationary.

3. Ina combined furnace and stoker, the combination of a ire box having a rotatable grate, a

partition extending upwardly and above said grate for sweeping ashes therefrom, whereby to provide a clear space on the grate to receive fuel thereon, a motor driven intermittently rotated crank shaft having a crank, drive gearing between said shaft and grate including an intermittently operated driving connection, a fuel delivery conduit having one side wall extending radially with respect to the grate and forming the support for s'aid partition, said fuel delivery conduit having a throat opening to the fire box above the grate adjacent said partition, a ram reciprocating in said fuel delivery conduit, .and a connection between said ram and the crank of the crank shaft for moving the ram toward the grate while the latter is stationary.

4. In a combined furnace and Stoker, the combination of a re box having a rotatable grate, a motor driven intermittently rotatedr crank shaft having a crank, a `beveled gear wheel supporting said grate, a bearing for said beveled gear wheel,r

`an intermittently rotated Shaft having a beveled pinion thereon meshing with said gear wheel, drive gearing between said crank shaft and in1 termittently rotated shaft including an intermittently operated driving connection, a fuel delivery conduit having one side wall extending radially with respect to the grate and having a throat opening to the fire box above `the grate, an ash sweeping partition extending upwardly and above said grate substantially in line with said side wall, and being supported by said side wall, a ram reciprocating in said fuel delivery conduit, and a connection between said ram and the crank of the crank shaft for moving the ram toward the grate while the latter is stationary.

5. In a combined furnace and Stoker, the combination of a fire box having a rotatable grate, a motor driven intermittently rotated crank shaft having a crank, a beveled gear Wheel supporting said grate, a bearing for said beveled gear wheel, an intermittently rotated shaft having a beveled pinion thereon meshing with said beveled gear wheel, a pair of intermeshing gear wheels, one of which is a mutilated gear wheel, a beveled gear wheel connected to the driven one of said gear wheels, a beveled pinion on said intermittently rotated shaft meshing with said last mentioned beveled gear wheel, a fuel delivery conduit having one side wall extending radially with respect to the grate and having a throat opening to the nre vbox above the grate, a ram reciprocating in said fuel delivery conduit, and a connection between said ram and the Acrank of the crank shaft for moving the ram toward the grate while the same is stationary.

6. In a combined furnace and Stoker, the combination of a re box having a rotatable grate, a trap door pfivotally carried by said grate, an annular track upon which said trap door rides, said track having a downwardly offset portion therein permitting the trap door to drop, motor driven means to intermittently rotate said grate, a stationary partition extending upwardly and above said grate in a direction radial with respect thereto, a fuel delivery conduit having one side wall substantially aligned with said partition and having a throat opening to said re box, said side wall forming the support for the partition, a ram in said fuel delivery conduit for charging fuel upon said grate in a direction approximately radial thereto, and a connection to said ram and motor driven means for itnermitl'ently reciprocating said ram in timed relation to the move ments of the grate.

7. In a combined furnace and Stoker, the comn bination of a furnace body, a smoke pipe leading therefrom, a damper in said Smoke pipe, a re box having a rotatable grate, a motor, driving means driven by said motor to rotate the grate, a fuel delivery conduit having a throat opening to the re box, a ram in said fuel delivery conduit, a connection between said ram and driving means, electrical time control means for starting and stopping the motor, at definite intervals, and manually operable time setting means for `Changing the lengths of intervals for starting the motor, a member of said time control means having exible connecting means connected to said damper, whereby the setting of the time control means varies the position of the damper.

8. In a combined furnace and Stoker, `the combination of a furnace body, a smoke pipe leading therefrom, a nre box having a rotatable grate,

a motor, means driven by said motor to rotate the grate, a fuel delivery conduit having a throat openingto the fire box, a ram in said fuel delivery conduit, a connection between said ram and motor driven means, a damper in said smoke pipe, electrical time control means for starting and stopping the motor and actuating said damper, comprising a motor driven disc hav ing annular rows of contacts, an adjustable con tact carrying member having contact fingers for making contact with the contacts of the several rows, said contact fingers comprising terminals in an electric circuit to the motor, operative connections between said contact carrying member and damper, and means to adjust said contact carrying member including an indicating dial.

9. In a combined furnace and Stoker, the combination of a furnace body, a smoke pipe leading therefrom, a re box having a rotatable grate, a motor, means driven by said motor to rotate the grate, a fuel delivery conduit having a throat opening to the fire box, a ram in said fuel delivery conduit, a connection between said ram and motor driven means, electrical time control means for starting and stopping the motor, a damper located in said smoke pipe, and means actuated by said control means for actuating said damper.

GEORGE H. CUSHING.

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