US1992061A - Mechanical stoker - Google Patents

Description

Feb. 19, 1935.

A. B. FAHNESTOCK MECHANICALSTOKER 3 Sheets-Sheet l Filed March 29, 1950 JNVENTOR /D/QM FHM/55750( B Y C? ATTORNEY Feb. 19, 1935.'

A. B. FAHNESTQCK MECHANICAL STOKER lFired March 29, 195o 5 Sheets-Sheet 2 INVENTOR 50i/VE. 75mm-5 Tac/ BY ATTORNEY Feb- 19, 1935- l A. B. FAHNEsTocK 1,992,06

MECHANICAL STOKER Filedv MaIfCh 29', 1950 5 Sheets-Sheet 3 REVERSING' ENGINE 1r WIS' ATTORNEY Patented Feb. y19,1935

MECHANICAL STOKER Adam B. Fahneatock. Manhasset, N. Y., assigner to The Standard Stoker Company, Incorporated, a corporation of Delaware Application March 29,

19 Claims.

My invention relates to stokers for locomotive or other boiler furnaces, and is more particularly concerned with mechanical stokers wherein a rotating disc is employed for projecting the fuel over the furnace grate. In stokers of this character provided in the I past, the fuel is projected and distributed over "I sides of the re.

the grate by a disc rotating at different rates of speed during successive periods, gradually increasing to a maximum and then gradually diminishing to a minimum; the disc then being rotated in the opposite direction through corresponding gradually increasing and gradually decreasing rates of speed, in order to spread fuel to both 'I'he disc of such stokers both projects and distributes the fuel over the fire, this together with the method of operation results in anl overlapping of the fuel streams thrown to each side of the firebox causing'a heavier fire in the center of the iirebox, and little if any fuel at all is delivered to the rear corners.

The efficiency of a boiler depends largely upon the amount of fuel fed per unit of grate area at equal intervals of time, andthe uniform and even distribution of this fuel over the entire grate. My present invention makes this delivery of the fuel possibi/e and it is one of the principal objects of the invention.

This invention is an improvement upon the structures of the past and another of its objects is the provision of an automatically operable, periodic reversing mechanism, whereby the fuel projecting disc is rotated at a constant speed and periodically reversed to project fuel uniformly and evenly first over one side of the grate and then over the other.

A further object of my invention consists in the provision of a rotatable disc without the boiler furnace cooperating with a deflector extending within the furnace, to spread the fuel evenly and in equal amounts over the entire grate.

A still further object of .the invention is to provide in a stoker of the character specified a novel construction of fuelcasing and associated parts such that the fuel will be directed to a respective side of the iirebox dependent upon the direction of rotation of the disc, at the same time preventing overlapping of the fuel streams to avoid formation of banks vcir thick spots in the rebox.

My invention also contemplates and has for another one of its objects cooling those parts of the stoker that are exposed to the heat of the furnace by providing such a construction that 'v the rotary disc acts as a fan or pressure blower 1930, sex-m1 No. 439,887

(ci. 11e-115) to direct a cooling stream of air under the exposed parts; and further the disc blower functions to prevent fuel `dirt from sifting in to the gearingof its operating mechanism, such dust being lblown into' the furnace beneath the main supply 5 of the fuel.

Somewhat more specically a further object of this invention is to obtain the longest trajectory path for the fuel with a minimum speed of the rotating disc.

A still further object of my invention is the provision of a simple and novel mechanism fr producing periodic reversal of the disc without materially changing its constant rate of speed.

Many advantages and additional objects of my invention will be apparent from the following description and the drawings, in which Fig. 1 is a central vertical longitudinal section of the stoker as applied to a locomotive;

Fig. 2 is an enlarged detail longitudinal sec: tion of a portion of the stoker;

Fig. 3 is a plan section on the line 3-3 of Fig. 2;

. Fig. 4 is a detail vertical section on the line 4-4 of Fig. 3;

Fig. 5 is a plan section on the line 5-5 of Fig. 4, showing the driving mechanism;

Fig. 6 is a front elevation of the driving engine showing a part of the reversing mechanism;

Fig. 'Z is an isometric view of the rotating disc with a portion broken away; and

Fig. 8 is a detail section on the line 8-8 of Fig. 5.

The rear portion of a locomotive is indicated generally at`10, a portion of its tender at 11, its backhead at 12, its grate at 13, and the cou- 35 pling connecting the locomotive and tender at 14. The fuel transfer conduit comprises the usual tender trough 15, telescoping housing 16, and screws 17 and 18 disposed therein, connected at their adjacent ends by universal joints of conventional form as illustrated. Carried at the forward end of the trough is a crusher 19 which is adapted to engage the coal which has been moved forward by the screw 17. The forward portion of the telescoping housing 16 communicates with the forwardly and upwardly curved casing 20, by means of an elbow 21 universally connected at its rearward end to the housing 16 and rigidly connected at its forward end to the casing 20 by suitable means. To the casing 20 is attached the casing 22, said casing 22 as best shown in Fig. 3 having fastened thereto ,the driving engine 23 on one side and the reversing mechanism 24 on the other side. Extending within both the easing 22 and me forwardly 5 curved casing 20' is located a disc 25 provided on its upper face or fuel supporting surface with the ribs or projections 26. It will be observed that the fuel supporting surface of said disc. is slightly below the oor of the feed casing 20, but forms, in effect, a forward continuation thereof. The casing 2O has an opening at its forward end communicating with the ring opening 27 through which the fuel is fed, and is open at its rearward end for receiving fuel from the conveyor. Both the forward curved portion 2Q and the casing 22 are secured through the flanges 28, 28a and 29 respectively, to filler plate 30, which in turn is fastened to the backhead 12 of the locomotive.

The sidewalls of the casing 20 taper inwardly from the center line of the disc 25 forward, as is best illustrated in Fig. 3. In constructions not having tapering sidewalls and in which firing is done by periodic reversal of a disc, a fan shaped bank of fuel is formed in the rebox extending forwardly from the backhead, since the area covered by the bank receives a double supply of fuel. It Was noted that a great amount of fuel seemed to follow along the sidewall of the casing, this fuel being that which could easily get out of reach of ribs or vanes provided on the disc, being thrown against the sidewalls of the casing at a point approximately in line with the center line of the disc parallel to the backhead and forming the above described bank. To restrain the fuel and hold it longer in contact with the propelling ribs 26, the casing is drawn in at the sides from the center line of the disc forward. This construction almost entirely eliminates the above described fan shaped bank of fuel in the firebox, and prevents overlapping of fuel along the center line of the rebox. By clockwise rotation of the disc 25 the right half of the box may be fired, and the left half of the box by counter-clockwise rotation.

The disc 25 comprises ahub portion 31 which is bored out to receive an upright shaft 32 supported on radial and thrust bearings 33 and 34. The shaft 32 is preferably inclined so that the disc is tilted at an angle of eight degrees from the horizontal, since at this inclination it is possible to obtain the longest trajectory path for the-fuel with a. minimum speed of the rotating disc. While eight degrees is the preferred inclination it will be understood that the inclination may be more or less than eight degrees if desired. Also if desired, the disc may be mounted horizontally without departing from the spirit of my invention.

The ribs or projections 26 on the disc 25 may be of any shape but are shown in the drawings with curved faces which flare outwardly from the hub to the peripheral portion of the disc 25,. The ribs may be cored outl as shown in Figures 1 to 3 in order to reduce their weight. The underside of the disc 25 is provided with ribs 35. The casing 22 is so designed as to provide the space 36 under and around disc 25 and the opening 37 at the rear of and near the center of the casing. The space 36 enlarges in width toward the front and in combination with the ribs 35 becomes a pressure blower. Air entering the opening 37 is thrown out through the openings 38 around the disc 25'and the opening39' at the front of the Stoker, whence it passes under the deflector plate 40 to the rebox. This flow of air sweeps the coal dust into the rebox and thus prevents it from sifting into the gears and bearings of the 745i gearbox. The current of air passingunder thedeector 40 constitutes a cooling mediumfor the deflector and other parts of the Stoker which are exposed to the heat of the rebox. The current of air entering the flrebox assists in the comof fuel at the corners of the redoor opening and exerta directive influence on the projected fuel.

eflector plate 40 is supported from the backhead 12 by the depending portions 42. The deector plate/l0 is provided with a pair of grooves 43 and 44/having their front walls curved forwardly and laterally for directing a certain amount of the fuel laterally into the back corners of the flrebox, these curved walls being raised slightly above the plane of the plate to constitute the 4ribs 45 and 46 which act to intercept a portion of the fuel being delivered into the frebox, Aand directing the portion intercepted to the rear of the rebox.

The disc 25 is driven by the engine 23. The drive mechanism as best shown in Fig. 5 is self explanatory and requires no detailed description. The drive shaft is indicated at 47 and communicates through suitable reduction gearing with the intermediate shaft 48 which in turn operates the disc shaft 32 through the engaged gears 49 and 50. The drive shaft 47 and the intermediate shaft 48 are supported on suitable bearings. The shaft 32 carries the gear 50 which is comprised in means for rotating the disc 25 rst in one direction and then in the opposite direction.

Referring now particularly to Fig. 4 and Fig. 5; the reversing mechanism comprises the casing 51 enclosing a shaft 52. The shaft 52 is operated from the intermediate shaft 48 through the worm 53 mounted on the intermediate shaft 48 which engages the worm gear 54 mounted on the shaft 52. The disc and reversing mechanism yare operated from the same shaft in timed relation with each other. The gear shaft 52 projects upward and the upper or lead portion 55 is threaded and carries the nut 56. The movement of the nut 56 along the threaded shaft 55 in turn moves the shaft 57 by means of the forked arm member 58. The forked ends of the arm 58 are fastened to the nut 56 while the opposite end communicates with the shaft 57: The shaft 57 is connected to a toggle switch if the drive is'electric or to a toggle reverse mechanism shown in Figures 5' and 6. The direction in which the disc 25 rotates may bereversed at any predetermined uniform intervals of time by the proper selection of reduction in Igearing and the number of threads on shaft 55. Reversal of the disc approximately every two minutes has been found to be desirable, but it will be obvious that the time interval between reversals may be varied greatly and still be operative and produce good results.

Referring to Figures 5, 6 and 8; 59 is an arm lfixedly connected at one end to the shaft 57; 60

is an arm fixedly attached at one end to the forward and reversing shaft 61, best shown in Figure 8; 62 is a spring connecting the free ends of the arms 59 and 60. The shaft 61 is provided with slots 63 which are adapted to engage the key 64. Pressure is exerted on the key 64 through the coiled spring 65. The movement of the nut 56 along the threaded shaft 55 moves the shaft 5'7 through the arm 58. The shaft 57 in turn raises the arm 59 increasing the tension on the spring 62 until it overcomes the pressure exerted on the key 64, through the spring 65. The tension on the spring 62 causes the arm 60 to jump and assume the position shown in broken lines in Figure 6, and thereby moves the shaft 61 and forces the key 64 out of engagement with the slot 63 in saidshaft. Immediately after the arms I59 and 60 have assumed thenew position, the tension on the spring 62 is released and the key 64 which was forced from one of the slots 63 is forced into the other slot by the pressure of the spring causing reversal of the steam admission port in the engine. The slot and key arrangee ment 'described prohibits any rotary movement of the shaft 61, which would affect the operation of the motor 33, until the. arm 59 has reached its maximum reversing position. Tension on the spring 62 then will be suflicient toovercome the action of the spring 65 in restricting rotation of the shaft 61. When the shaft 61 moves it is quickly pulled to the end of its travel by the spring 62 and the key 64 will then engage the other slot 63. The movement of the arm 60 from the position shown in full lines to the position shown in broken lines, Fig. 6, and vice versa is rapid and almost instantaneous, and after reversal of the disc in the direction of rotation the maximum speed is quickly restored. Reversal in the direction of rotation of the disc 25 takes place almost instantaneously and there is no ap' preciable slowing up of the disc before reversing and no appreciable acceleration after reversal.

Inoperation., coal which enters the trough 15 from the bin 11 ,is carried forward by rotation of the screw 1'7 into the telesooping housing 16 from whereit is carried forward by rotation of the screw 1B. The coal is urged forwardly and upwardly through the rearward end of the casing 20 onto the rotatable disc 25. With the disc rotating in clockwise direction fuel is fed to the right half of the firebox and counter-clockwise to the left half, and by reason of the tapering sidewalls of the casing 20 nooverlapping of fuel takes place along the center line of the firebox. A part of the fuel projected forwardly from the disc 25 is intercepted on the deector plate 40 and the novel construction of the plate 40 permits of fuel to reach the rear corner of the. firebox on the respective side toward which the disc is rotating.

I claim: 1. In a stoker, in combination, a firebox, a fuel delivery casing operatively associated therewith, a rotatable fuel projecting disc mounted in the floor of said casing for propelling fuel forwardly therefrom into said firebox, the fuel supporting surface of said disc forming an approximate continuation of said floor, and means for delivering fuel forwardly into said casing through the rear end thereof in a plane substantially parallel to the fuel supporting surface of said disc to 'that portion of said disc remote from the firebox.

2. In a stoker, in combination, a rebox having a firing opening in its backwall, a fuel delivery casing operatively associated therewith and at its forward end communicating with said firing opening, a rotatable fuel projecting disc mounted on an upstanding axis in the floor of said casing for propelling fuel forwardly through said ring opening in a plane substantially perpendicular to said axis, the fuel supporting surface of saidv disc forming an approximate continuation of said floor, and a conveyor delivering fuel forwardly into said casing through the rear end thereof, said casing and disc being arranged so that the fuel is delivered' continuously to said disc in the plane f the path of its rotation.

3. In va Stoker, in combination, a firebox havlivery casing outside of said firebox and operatively associated therewith, said casing opn at its forward end to communicate with said firing opening, a rotatable fuelv projecting disc mounted on an upstanding axis in the floor of said casing for propelling fuel forwardly through said ring opening in a plane substantially perpendicular to said axis, the fuel supporting surface of said disc forming an approximate continuation of said oor, a conveyor delivering fuel forwardly through the rear end of said casing to that portion of said disc remoteffrom the firing opening, and deflecting means /within the firebox arranged to intercept a portion only of-the propelled fuel directing the intercepted portion to the rear corners of said firebox to assist said disc in uniformly distributing the fuel.

4. In a device of the class decribed, a fuel casing having top, bottom, and sidewalls, said casing being provided with an open forward end and an opening in its rear` end through which fuel is delivered forwardly toV said casing, and a rotatable disc mounted in the casing floor and arranged therewith to receive `fuel continuously from said opening in the rear end in the plane of the path of the rotation of said disc and project it through said open forward end of the casing, the fuel supporting surface of said disc forming an approximate continuation of said door, the opening in the forward end of said casing being of less width than the diameter of said disc.

5. In combination, a firebox, a fuel delivery casing operatively associated with said rebox, means for continuously supplying fuel forwardly to said casing through the rear end thereof, a rotatable disc in said casing arranged to receive a continuous supply of fuel on that portion of its ing a firing opening in its backwall, a fuel de.-

surface remote from the firebox and periodically distributing the fuel to each side of the firebox, and means for rotating said disc first in one direction and then in the opposite direction at a ,constantv speed for a predetermined period of time.

6. In combination, a firebox, a fuel delivery casing operatively associated with said firebox, means for supplying fuel forwardly to said casing through the rear end thereof, means including a rotatable disc in said casing receiving the fuel on that portion of its surface remote from the firebox and periodically projecting the fuel to'each side of the firebox, and a deflecting means within the firebox acting to direct a portion of the propelled fuel to thefrear corner of the firebox on the side to which the fuel is being delivered.

7. In combination, arebox, a fuel delivery 1 the propelled fuel to the rear corner of the flrebox on the side to which the fuel is being delivered.

8. In combination, a firebox having a ring opening in the end wall thereof, a fuel casing opening into said ring opening, a rotatable disc. mounted in said casing, means for periodicallyI rotating said disc in opposite directions for timed intervals, a conveyor for delivering fuel forwardly onto said disc through the rear end of said casing in a plane substantially parallel to the fuel supporting surface of said disc, said disc periodically projecting the fuel to each side of the rebox, and deflecting means within the flrebox acting to direct a portion of the propelled fuel to the rear corner of the rebox on the side to which the fuel is being delivered.

` 9. In a Stoker, in combination, a firebox having a firing opening therein, a fuel delivery casing in communication with said firing opening, a rotatable fuel projecting disc inclined forwardly and upwardly toward said opening and mounted in the door of said casing for propelling fuel forwardly therefrom into said flrebox, and means for delivering fuel forwardly into said casing ,through the rear end thereof to the portion of said disc remote from the flrebox.

10. In a stoker, in combination, a flrebox having a ring opening in the end wall thereof, a fuel casing opening into said firing opening, a rotatable fuel projecting disc inclined forwardly and upwardly toward said opening and mounted in the' floor of said casing for projecting fuel forwardly therefrom into said flrebox. the fuel supporting surface of said disc forming an approximate continuation of said floor, means for delivering fuel forwardly to said casing through the rear end thereof in a plane 4substantially parallel to the fuel supporting surface of said disc, and deflecting means extending into the rebox forwardly from said disc.

11. In a mechanical Stoker, the combination of a fuel casing having converging sidewalls, a rotatable disc mounted in the oor of said casing and arranged to receive fuel in a plane substantially parallel to the fuel supporting surface of said disc, said fuel supporting surface forming an approximate continuation of said oor, a deflector plate in communication with said fuel casing and arranged to receive fuel therefrom, said deector plate having its rearward edge following the contour of said disc, and means disposed at the forward end of said deflector plate for intercepting a portionof the fuel and deecting it laterally.

12. In a mechanical stoker, the combination of a fuel casing having converging sidewalls, and

an opening in its rear end for delivering fuel, a rotatable disc mounted in the floor of said casing and arranged to receive fuel forwardly from said opening in a plane substantially parallel to the fuel supporting surface of said disc. said fuel supporting surface forming an approximate continuation of said door, a deflector plate in communication with an opening in the forward end of said casing for receiving fuel therefrom and means disposed at the forward end of said defiector plate for intercepting a portion of the. fuel and deecting' it laterally.

13. In a mechanical stoker, the combination of a fuel casing having converging sidewalls, a rotatable disc mounted in the floor of said casing and arranged to receive fuel `in a plane substantially parallel to the fuel supporting surface of said disc, said fuel Supporting surface forming an approximate continuation of said door, and a deflector plate so arranged that the sidewalls of said casing form retaining sidewalls for the rearward portion of said deflector plate, shoulders on said deflector plate constituting extensions of the casing walls, grooves disposed in the forward end of said defiector plate curving forwardly and laterally and ribs carried on said plate and forming walls for said grooves.

14. In combination witl` a rebox having a firing opening in a wall thereof, a mechanical stoker comprising a casing in communication with said rebox through the ring opening thereof, a fuel projecting disc rotatably mounted in said casing to rotate about an upstanding axis, the underside of said disc together with said casing forming a chamber which communicates,with said firing opening at its forward end and with the atmosphere at its rearward end,

the underside of said disc being in the form vof a blower fan arranged to discharge the current of air entering the rearward end of said chamber through the forward end thereof into the flrebox.

15. In combination with a firebox having a ring opening in a wall thereof, a mechanical stoker comprising a casing in communicationv with said flrebox through the ring opening thereof, a fuel projecting disc rotatably mounted,

in said casing to rotate about an upstanding axis, drive mechanism for rotating said disc disposed beneath the fuel supporting surface of saidI ydisc, the under side of said disc together with said casing forming a chamber which communicatesy with said firing opening at its forward vend and with the atmosphere at its rearward end, and

fan blades secured to said disc intermediate the under side of said disc and said drive mechanism, said fan blades arranged to discharge the current of air entering the rearward end of said chamber through the forward end thereof into the flrebox. l

16. In combination with a flrebox having a firing opening in a wall thereof, a mechanical stoker comprising a fuel deflector plate extending into the flrebox through said opening, a casing, a fuel projecting discl rotatably mounted in said ycasing to rotate about an upstanding axis, said casing having a floor -forming with the underside of said disc a chamber in communication with said firing opening at its forward end and with the atmosphere at its rearward end, the underside of said disc being in the form of a blower fan arranged to discharge the current of air entering the rearward end of said chamber through the forward end thereof into the rebox, such current of air impinging the underside of said fuel deflector plate.

17.` In a mechanical Stoker, the combination of a rotary disc for projecting fuel, means for conveying fuel to said disc, and mechanism for alternately rotating the disc in one direction vfor a predetermined period and then in the opposite direction for a predetermined period, said mechanism being constructed to actuate the disc for a plurality of revolutions during each period including a plurality of successive revolutions of the disc for the greater portion of each period at the same speed.

18. In a mechanical stoker, the combination of a. rotary disc for projecting fuel, a casing enclosing said disc open at one end for delivery of fuel to said disc and open at the opposite end for the discharge of fuel therefrom by said disc, fuel deflecting means adjacent the discharge end of the casing positioned in the path of the projected fuel, and mechanism for alternately rotating the disc in one direction for a. predetermined period and then in the opposite direction for a predetermined period,- said mechanism being constructed to actuate the disc for a plurality of revolutions during each period including a plurality of successive revolutions of the disc for the greater portion of each period at the same speed.

19. In combination with a rebox having a firing opening, a casing having an opening at one end in communication with said ring opening, a rotary fuel projecting disc mounted in said casing for projecting fuel therefrom through said nring opening, fuel deecting means adjacent the firing opening positioned in the path of the projected vfuel, and vmechanism for alternately rotating the disc in one direction for a predetermined period and then in the opposite direction for a predetermined period, said mechanism being constructed to actuate the disc for a plurality of revolutions during each period including a plurality of successive revolutions of, the disc for the greater portion of each period at the same speed.

ADAM B. FAHNESTOCK.

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