US1018690A

US1018690A - Automatic stoker.

Info

Publication number: US1018690A
Application number: US57595110A
Authority: US
Inventors: David J Ames
Original assignee: Individual
Current assignee: Individual
Priority date: 1910-08-06
Filing date: 1910-08-06
Publication date: 1912-02-27
Anticipated expiration: 1929-02-27

Description

11. J. AMES. AUTOMATIC S'IOKER. APPLIOATON FILED AUG. 6, 1910.

. Patented Feb. 2v, 191.2.

SHEETS-SHEET 1 a e i D. J. AMES.

` AUTOMATIC STOKER.

APPLICATION FILED AUG. S, 1910. Y

` 1,018,690, .Patented Fe10.27,1912.V

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D. J. AMES. AUTOMATIC STOKBR.

APPLICATION FILED AUG.6,1910.

l L'GlSQG. Patented Feb;27,1912.

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DAVID J.- AMES, or AUSTIN, MINNESOTA.

To all whom if may concern."

Be it known that I, DAVID J. AMES, a citizen of tlie" UnitedStates, residing at Austin, inI the county of Mower and State of Minnesota, have invented certain new and useful Improvements in Automatic Stokers; and I do hereby declare the following to be a full,

clear, and exact description of the invention, such as will enable others skilled in the art to which it'fappertains to make and use the same'.

My invention has for its special object tov 1provide an improved mechanical Stoker, and

to this end it. consists of the novel devices and combinations of devices hereinafter de- :scribed and defined in the claims.

` frdnt elevation of an ordinary boiler tire rbox having my invention applied thereto some parts being broken away. Fig. 2 is a detail view partly in elevation and partly in vertical section and withl some parts broken away showing a variable speed mechanism for operating the stokcr proper. Fig. 3 is a view partly in plan and partly in horizontal section and with some parts broken away showing my improved stoker and its actuating mechanism applied in connection with th'e grates of the fire box. Fig. 4 is a detail in section taken approximately on the line mj* of Fig. 3. Fig. 5 is a side elevation showing the stoker applied to the grate and other parts of the furnace being removed. Fig. G is a transverse vertical section taken through the grate on the line of o1 of Fig. 5. Fig. 7 is a plan view of the fuel feed screw, and Figs. 8 and 9 are sections` taken respectively on the lines :as fr and .5.119 az of Fig. 7.

0f the parts of the furnace the numerall indicates the masonry walls and the nu* meral 2 a door which opens into the tire box above the grates. So far as my invention concerned, the grate may be of'any suitable form, but as shownand preferred it is made up..of a rectangular toothed lixed structure. 3, and la multiplicity of rocking toothed bars 4. The lixed grate structure 3 is hori- Lzontally disposed and Vits teeth are interlapped with the teeth of the rocking grate bars 4, the latter at their ends being det-ach- Speeication of Letters Patent. Appli-cation filed August 6.1910. Serial No. 575,951.

At the transverse center the fixed gratel Parenteel ret.' 2r, i912.

structure 3 is formed with a large longi- .y

tudinally extended fuel admission passage irthat is in communication with the delivery end of a fuel supply spout 6. This fuel spout 6 is preferably a eas-t structure havin at its extreme outer end a detachable head connected thereto, as shown, by short nutted bolts 8, best shown in Fig. 5. The outer and receiving end of the spout 6 is in communication with the lower end of a fuel supply hopper 9; one wall 9a of which is inclined at an angle of approximately 45 degrees, and terminates at a point substantially di rectly above the axis ofthe said spout 6. This latter feature is important and is for a purpose which will be hereinafter noted. The delivery end of the spout G is tapered so that its bottom rises quite abruptly throughout that space underlying the fuel delivery passage 5 of the grate The rock ing grate bars 4 at their intermediate portions. are provided with depending arms la that are connected by link l0. O ne of the arms 4e is also connected by a short link il to the depending arm l2 of a horizont-al rock shaft 123 mounted in suitable bearings 11i on the spout G and provided at its front end with a rigidly secured arm l5, the pur pose of which will hereinafter appear.

lVorking within the feed spout 6 is a spiral feed screw of novel construction. indicated as an entirety by the numeral 16. Between the points marked a-Z)` (Fig. 7) the spiral blade of this feed screw 1G is given a constantly increasing pitch or travel, for a highly important purpose presently to be described, and between the points marked p5 o-d Ithe said feed screw is formed in ap proximately. flat contiguous blade sections 16a' that are obliquely set with adjacentl sections reversely inclined. The blade sections 16a work in that portion ofthe spout 6 which underlies the fuel delivery passage The feed screw 15 is preferably cast integral with an axial shaft, the inner vend of which is journaled in the seat formed in the delivery' end of the spout 6 below the grate. The outer end of the 'shaft of the said feed screw is preferably square at 16b and is extended outward through the -head T of the spout G. 'lfhe said head 7 and the flanged end of the spout (S are recessed vto afford la seat for a coperatingworml? worm` gear 18;Y The said gear'18is seated.V

on the square end -16b ofthe feed screw 'shaftwhile the worm 17 is secured to one ve'n`d"of an operating shaft 19. One end o f theshaft v 19 is journaled in a divided'seatfor'medin the depending portions of the head/ and flanged upper end of the spout 6, and the.

other end of the said shaft 19 is journaled in a gear case or housing 20 shown as rigidly secured to the floor in front ofthe furnace and at one side ofv the fuel supply hopper 9. Preferably the 4housing 20 is aY divided or two part structure the sections of which are rigidly secured by suitable bolts and one section vof which in Fig. 2 is removed.

Within the housing 20 the shaft 19 carries a pluralityof spur gears 21 of varying. diameter.

spur gears 22 that `are normally loose on a. shaft 23 that is extended through the hubs The gears 21 are in mesh with thereof, and is johrnaled in the housing 20 and'with freedomfor endwise movements.

' The gears 21 and the gears 22 are in reverse conical larrangement so that by coupling the drivingv shaft 23 ,to different members of the gears 22 a variable speed transmission mechshown, a -sprocket 26 connected to the said shaft 23 by a long key 27. The shaft 23 moves' through the sprocket 26 and-the hub ofthe latter is provided with a groove 28 that is engaged by a forked bearing 29 `rigidly secured to the housing 20. rlhe said bearing 29 holds the sprocket against lateral movements, but'permits the same to freely rotate. A sprocket .chain 25 runs over the sprocket 26.

The shaft 23 is adapted to be given -axial movements and to be set in its different operative and inoperative positions preferably by means' of the rack bar 30 thatis mounted in thetop portion of the housing 20 -and is provided with a depending end 31 of4 which. the corresponding end .on the. said shaft 23 is swiveled. rI he teeth of the rack 30 are engaged by a spur pinion 32 that is 'rotated and mounted in a suitable seat formed within the housing 20 and is provided with a projecting shaft 33 which in practice will be equipped with an operating crank 34. The rack 30 is adapted to' be locked in its various positions by a lock dog 35 pivoted on top of the housing 20 and engageable with notclr`36` in the top of .the said rack 30,

veral spaced perforations Y cated variable distances from the axis of lthe said crank head and adapting lthe lower end of the lock 38 to be .connected to said crank'disk for variable thrust `orcrank actions.

that the surface of the'blad'eslaof the feed screwin a radial direction are straight or approximately flat; and by reference to By reference to Fig, 9 it will be noted.,

Fig. 8 it will be noted that the operative surface of the main body of the feed screw in a radial direction is made concave. Furthermore, the concavity of the working face of the feed screw is such that its greatest depression is at the central portion of the said working face. This latter feature particularly is of verygreat importance, as will be presently more fully explained.

The coal or similar fuel which is to be fed to the furnace is delivered in a suitable way into the hopper 9. The direction or rotation ofthe feed screw 16 is indicated on )Figy 4.

by reference to which it will be seen that the spiral blade of the feed screw cuts off the fuel from the bottom ofthe hopper against the sharp overlying edged portion of the inclinedAv bottom section 9EL of vsaid hopper, in such manner that the body of fuel in the hopper is not forced with anyconsiderable pressure against the side of the hopper.l Coal dust or screenings are very largely and quite generallyused in furnaces employing automatic stokers, and this fo-rm of fuel when used by a feed screw through a spout has'a very great tendency'to pack tight in the spout and produce such .friction that it is practically impossible to feed-the material as far as usually required to deliver thesame properly to the furnace grates. In fact, it

frequently happens that very strong feed screws are twisted off in an attempt to deliver t-he fuel which has become tightly packed in the feed spout. It of course also follows that very great 'power is required to operate the feed screw even under-the most favorable conditions hereto provided for.

l My improved feed screw has been thoroughly tested in actual use and seems to be Aa solution of the problem of making a feed screw. operative for thel purposes above stated. Two highly important features contribute 'to this result. important of the two is the arrangement of the spiral feed blade with an increasing The iirst'and more pitch or travel in the` direction of the feed of the material. ral `space of increasing width and conducting capacity, in the direction of the travel of the material and therefore constantlyr relieves the material pressure whichr would, with a feed screw of constant pitch and di- 'ameter,A be accumulative and increasing.

secure ythe desired result, and it is further important that the'working face of the feed screw have its greatest conca-vity, or depression, approximately at its central portion,`

that is, about midway between its peripheryand the line of its junction with the screw shaft. This gives the vdesired relief from both outward pressure of the material being fed against the spout, and against the shaft of the screw. A third important novel feature of the feed screw is the arrangement of the alternated and approximately dat blade sections in space or capacity through whichthe fuel is delivered from the feed spout upward through the bottom of the grate. ward on to the top 'of the grate and insure good and proper `distribution of the fuel over the upper surface ofthe grate.

By adjustments of the shaft 23, inrespect. vto the gears 22, and already described, the

rate of rotation of the feed screw may be varied, without changing the speed of the driving sprocket 26 or the primary source of power, and this as is evident provides for j a variable supply of fuel to the furnace.

Through the described connections 37, 38, l5, l2, l1 and 10the rocking grate bars will be slowly but constantly moved so as to keep the proper amount of ashes worked' through the grate and into the ash pit. With the adjustable connection of the link 38 to the arm 15 and crank"head 37 makes it possible to vary at will,I the extent of oscillatory movement imparted to the rocking grate bars, at'each complete vibration. The num- `ber of vibrations, per unit of time of the rocking grate bars, varies with the speedof the rotation of the feed screw, but the grate cleaning action may be independently varied by the adjustmentsjust noted. .The ef This in itself gives a spi- These blade sections lift the fuel upthe bottom of said grate, and a feed screw rotatively mounted in said feed spout and provided at its'delivery or inner end with flat contiguous and connected obliqueblade sections, the adjacent-obliqueblade sections `'being reversely inclined, and the. saidV oblique sections being arranged to work in- 70- the-space through which the fuel is delivered upward from the said feed spout through said grate.

2. The combination with `a furnace and a I grate therein, of a feed spout leading into' -said'furnace and opening upward through the bottom of said grate, anda feed screw rotatively mounted in said feed spout, the spiral blade of'v which screw throughout the main body portion thereof having` aprogressively increasing pitch in the direction of the feed of the .material into the furnace, the wbrking face of said blade beingconcave in cross section, andthe said feed screw at the point of delivery of the fuelupward through said grate being provided v,with contiguous andconnec-ted fiat blade sections, the adjacent members-of which are inclined in reverse directions, and. the said' spiral and fiat blade lsections being cast integral with said feed-screw and the 'firstv of said Hat blade sections being integrally united with the spiral blade -of saidscrew.4

3. The combination with a'furnace and .a grate therein, said grate having rocking sections, of' a feed spout eXtendin-ginto said furnace and arranged to deliver the fuel upward from the bottom of said grate, a feed screw working in said feed spout, a powerl driven variable speed transmission mechanism for driving said feed screw, and connections from the said variable speed mechanism for oscillating the said rocking grate sections, the said grat-e operating connec" In testimonywhereof I aflix my signature in presence of twowitnesses.

'Witnesses: Y i l R. A. CARMICHAEL, S. A. SMrrir i DAVID J.I autres.4` l