US2250181A - Automatic stoker - Google Patents

Description

July 22, 1941./4` G, H. cRoclER AUTOMATIC sToKER Filed oct. 12, 1937 sym INN.. J L1 .M r und" JW, hmmm.. Mm. .Nm N n. mm l En @NNY @NRW Mmwwh .vw .www

HTI'ORNEY Patented July y2.2, I1941 AUTOMATIC STOKEB George H. Crocker, Lansdowne, Pa., asslghor to Newton Supply Company, a corporation of Delaware Application October 12, 1937, Serial No. 168,540

9 Claims. (Cl

The invention relates to automatic stokers and involves various improvements in the burner, the fuel feeding device, the ash removal device. the power apparatus, and certain combinations and arrangements of these parts of an automatic stoker with respect to each other.

Automatic stokers designed for domestic use are usually provided with a conveyor for deliv` ering fuel to the burner, a conveyor for removing the ashes discharged from the burner, a blower for producing a forced draft in the burner, and motor mechanism for driving the conveyors and the blower. It is usual in such apparatus to combine the motor and the blower as a unit for assembly with the other elements of the` stoker. The present invention has for its primary object a decrease in the cost of stakers of this general type. This object is accomplished by simplifying the structure of the different parts referred to above, by the elimination of various .features of construction, and by certain novel y arrangements of the fuel feeding device and the ash removal 'device with respect to the burner and the power unit.

The invention also has for an important object the provisionof a fuel feed `screw which is directly connected to the power unit so as to be driven thereby with a minimum reduction in speed, and consequently with a minimum number of parts in the speed reducing mechanism -ash pit of the furnace into a receptacle in the form of a bag made of paper or other suitable material. With such a structure the ashes from the stoker are automatically delivered to the receptacle, and the employment of paper bags makes possible the use of what would otherwise be a waste household product, and avoids the necessity of transferring the ashes from the receptacle to a collecting wagon or truck with the consequent annoyance caused by spilled ashes.

Another object of the invention is the provision on the conveyor for transferring the ashes from y the ash pit to the bag of a bag holder so designed secured to and extending outwardly from the ash pit of the furnace and having' a sleeve slidably arranged thereon and adapted to be removed therefrom with a lled bag and thereafter removed from the filled bagI and restored to the discharge tube. i

'A further object of the invention is the provision of means for preventing combustion gases from backing up through the fuel feed pipe from the burner and escaping into the furnace room. This object is accomplished by providing an air passage between the air chamber surrounding the grate and the outlet end of the fuel feed pipe, and by providing a funnel or pick-up device at the inlet of this passageway in the air chamber to insure the flow of air from the air chamber to the fuel feed pipe.

Still other objects and advantages of the invention will be apparent from the following description, taken with the accompanying drawing wherein:

Fig. 1 is a vertical setcional view showing my improvements in assembled relation with respectv 'to a furnace, the burner being lshown in elevation; v

Fig.l 2 is a transverse sectional' view taken on the line 2-2 of Fig. 1, slightly enlarged:

Fig. 3 is a vertical sectional view similar to Fig. 1, but slightly enlarged and showing the burner in section; and

Fig. 4 is a plan view, partly broken away, of the bag holder employed with the ash removal device.

My improved stoker has been designed particularly for assembly with a furnace III theretofore installed as part of a heating system, although it will be understood that it is also adapted to be incorporated with the furnace upon its installation in the system if desired. The stoker is of the type in which an upright burner Il is mounted in the ash pit l2 of the furnace I0 so that the upper end thereof projects into the combustion chamber I3 and ashes and other solid products of combustion are discharged over the upper edge of the burner and drop downwardly into the ash pit.

'Ihe body of the burner Il comprises a casing I4 which is generally circular in cross section and open at its upper end. 'I'he upper end of the casing Il is closed by means -of a grate in the form of a fire pot composed of a plurality of downwardly curved, tapering sections I5, the upper ends of which are supported upon the upper edge of the wall of the casing I4 and are secured thereto by bolts I6. As shown at I1, thev lower end of the side wall of the casing I4 tapers inwardly to a small central opening I8 which serves as a discharge opening for fine ashes and powdered coal which fall through the perforations I3 in the grate.

The lower end of the lire pot communicates with an opening 20 in a fuel conduit 2| which extends transversely through the wall of the casing |4 and terminates at its outer end in a faucet 22. The fuel conduit 2| is continuous with a bearing chamber 23 in the opposite side of the casing |4 and projecting outwardly thereof as a hollow boss 24 closed at its outer end except for a central shaft opening 25 in alinement with the fuel conduit. Y f Y Inasmuch as the burner casing |4 disclosed herein has been designed for use with stokers of various types, the form shown in the drawing is one in which an adapter 26 is employed for the purpose of permitting a distinct type of fuel feeding device to be used therewith This adapter is in the form of a hollow casting with the inner end thereof provided with a shaft opening 21 in alinementwith the opening 25 in the outer end of the hollow boss and with the axis of the fuel conduit 2|. As indicated at 26, Vthe inner end of the bore through the adapter 26 curves upwardly to anvopening 29 in alinementwith the opening 2|! from the fuel conduit into the lower end of the iire pot. The adapter may be retained in position in the fuel conduit by means of a set screw 3|! threaded through the wall of the faucet 22 into engagement with the adapter.

The fuel conduit 2| is connected to a source of fuel supply, 'such as a coal hopper or bin 3|, by means of a fuel feed pipe 32. The outer end of the fuel pipe 32 is supported bythe bin 3| and the inner end projects into the adapter 26 and is secured therein by a set screw 33 extending through an opening in the faucet 22 and threaded through the adapter into engagement with the pipe. In order to preventthe transmission of vibrations from the stoker to the furnace, the opening 34 in the furnace wall through which the fuel pipe 32 extends may be packed with asbestos rope or the like and cated at 35.

The fuel feeding device which I employ has been so designed as to operate at a speed much greater than the speed which has been necessary with stokers heretofore manufactured and used, the improvements in the feeding device being necessitated by reason of certain other improve- A ments which I have made in the power unit for the purpose of eliminating parts thereof as herelength of t,he .fuel pipe 32 and having the flight thereof formed of a round wire or rod wound,

spirally on the shaft and welded or otherwise se- `cured thereto at suitable intervals. As I have disclosed the same herein, and as a convenience in manufacture and installation, .the fuel-feed screw, as well as the extended driving shaft therefor, is made in sections of limited length. In the form which I now prefer to use, a shaft section 36 extends through the fuel conduit 2|, the shaft opening 21 in the inner end of the adapter, the bearing chamber 23, and outwardly through the opening 25 in the boss 24, with the opposite end extending outwardly Vinto the fuel pipe 32. The latter end of the shaft section 36 is provided with a night of wire 31 theinner end of which terminates within the fuel conduit 2| and merges with a night 38 comprising a single turn in the form of a spiral blade which serves as a propeller to feed the fuel upwardly into the fire pot at a rate slightly greater than that at which it is delivered by the wire spiral 31. The

diameter of the spiral blade 38 is preferably slightly greater than the diameter of the wire spiral portion 31, and the inner end of the propeller 36 preferably terminates a slight distance inwardly of the edge 39 of the opening from the adapter into the fire pot.

The outer end of the shaft section 36 is provided with a collar 4|| secured'thereon by means of a pin 4| and serving as a connecting member with the adjacent shaft section 42. -The end of shaft section 42 may be removably secured in the collar by any suitable means such as a bolt 43.

The fuel feeding means on shaft section 42 comprises a flight 44 `made of round wire wound spirally about the shaft and suitably secured thereto as heretofore described in connection with the flight 31 on shaft section 36. In this case, however, the flight 44 may be formed of vround wire having a diameter slightly less than the diameter of the wire forming the flight 31. With two conveyor sections of this character, it will be apparent that the feed of the fuel through that portion of the fuel pipe 32 adjacent the burner will be greater than the feed through the portion of the pipe adjacent the source of fuel supply 3|, and that such a construction facilitates the feeding of the fuel from the source of supply to the burner and eliminates any tendency suitably cemented as indiof the fuel to jam in the feed pipe. It will be understood that additional conveyor sections may be used if necessary to extend the conveyor to the source of fuel supply.

The fuel feed pipe which I now utilize for feeding a line grade of coal has an inner diameter of two inches. While a structure having other dimensions maybe devised, .I -have found from experience that the coal screw disclosed herein operates with entire satisfaction with a shaft having a diameter of one-half inch. The preferred diameter of the wire forming the flight 31 on the conveyor section 36 is iive-sixteenths of -an inch, with a pitch of two inches,'and the preferred diameter of the wire used for the flight 44 of the shaft section 42 is one-fourth of an inch, with a two-inch pitch. The preferred over-all diame- *ter of the propeller 33 is one and three-fourths inches. It vn'll be understood, however, that these dimensions are merely suggestive and are not intended to limit the scope of my invention in any manner.

The improvement which I have devised in ash removal mechanism includes a screw conveyor 45 extending transversely throughthe ash pit |2 below the burner |I. Ash directing plates 46 may be inserted in the ash pit, if desired, to deflect the ashes toward the ash screw 45. The ash screw extends outwardly. from the ash pit through an opening 41 near the bottom of the furnace wall, and through an ash discharge tube 48 projecting outwardly from the opening 41 and secured to the furnace wall by bolts 49. A sleeve 50 is-s1idably mounted on the ash discharge tube 48 so that it may be bodily removed over the outer end of the discharge tube. 'I'he sleeve 50 may be retainai in its innermost position by means of a bayonet Vslot 5| formed on its inner end for co-operation with a pin 52V secured in the discharge tube. The outer end of the sleeve 50 may be turned outwardly to provide a tapered of paper or other suitable material upon the sleeve to serve as areceptacle for discharged ashes.

The outer end of the ash screw 4i preferably extends to some distance beyond the outer end of the ash discharge tube 48 so as to properly feed ashes to the bottom of the bag. When the bag has been completely filled with ashes, the bayonet slot li in the end vof the sleeve is disconnected from the pin I2, and the bag, with the sleeve secured in the open end thereof, is removed from the ash discharge tube 48. The bag may then be placed in upright position and the sleeve may be removed therefrom after unfastenlng the strap Il. With such a structure,

`the bag may be removed from the ash discharge l device without danger of spilling ashes due to the withdrawal of the ash screw 45 from the bag. As will also be apparent, when paper -bags are used as ash receptacles, the open ends of the bags may be closed and secured by' strings, so that such receptacles may be collected without transferring the ashes therefrom and the usual spilling .of the ashes due to such transference.

'I'he power 4mechanismrwhichv I have devised for use with my invention is of the type wherein an electric motor 56 is directly associated with a blower 51, the fan of the blower being mounted on an extension of the motor shaft 5l. Such a unit is well understood in the art and a detailed description thereof is unnecessary to a complete understanding of the present invention. As disclosed herein, the blower casing terminates at its lower end in an air outlet 59 provided with a faucet 60 within which one end ofthe air pipe Il is secured. The opposite end of the air pipe Il extends through an opening 62 in the furnace wall, into a faucet structure 63 forming an air inlet on the wall of the burner casing for admitting air into the air chamber 64 between the grate I5 and the side wall lof the burner casing I4. Preferably the air supply pipe il is insulated from the furnace wall in the manner heretofore described with respect to the fuel pipe I2.

A plate 65 extending horizontally from the blower casing serves as a support for the motor ll which is suitably secured to the top thereof. A gear case Il secured to the underside of the plate il extends downwardly therefrom. The gear case contains two shafts arranged at right angles to each other. Shaft 61 extends through the case parallel to the motor shaft .58 and has a worm 6l secured thereon within the case. This worm meshes with the worm wheel I secured on a stub shaft 1li arranged at right angles to motor shaft 58. The worm shaft Il is driven by a large pulley Il secured on the outer end thereof and carrying a belt 12 which passes around a small driving pulleyll on the motor shaft. With this arrangement of power mechanism and transmission mechanism, the stub driving shaft III is positioned in alinement with the fuel feed screw and is connected directly to one end of a shaft section 14 by means of a coupling' 15 pinned to the stub shaft and removably bolted to 'shaft section 1l. Theloppoa'ite end of shaft section 1I is similarlylghected toshaft section I6, within the a'shpit I2, by a coupling 16.

'Ihe air outlet 59 from the blower casini provided n each side with a horizontal/l v 1r havingv a hole therein threaded/toV yreceive threaded adjusting legs 18 by meansof which the power unit is supported on the floor 19. A

5 lsecured tothe shaft thereof by the couplingV and pin connection Il. The opposite end of the stub shaft l2 has a sprocket wheel I4 secured thereon and driven by a4 sprocket chain Il passing around a driving sprocket Il secured-on the l stub driving shaft 'il in the gear caso.

As will beapparent from ,this arrangement of power mechanism, the fuel feed screw is connected directly to the stub driving shaft 1I. and theeash screw l! is driven directly from the l sprocket wheel 86 on the stub driving shaft. 'Ihe arrangement makes it possible to eliminate additional reduction gearing which5 has been necessary for the satisfactory operation of auto- 1 matic stokers heretofore manufactured, This 20 elimination of parts from the speed reducing mechanism ordinarily employed with automatic stokers results in an on rating speed forthefuel feed screw which'is much greater than has heretofore been practical. Such an increase in the speed of rotation of the fuel feed screw is possible with the stoker herein disclosed byreason of the unusual structure of the feed screw which `I-have devised.

As will be apparent from the drawing, the burner mechanism is supported in the furnace solely by the fuel pipe 32 and the air pipe Il, the fuel pipe having its outer end secured in the bin or other source of -fuel supply 3i; and its` inner end supported in the opening 34' in the 35 furnace wall. The air delivery pipe is supported at its outer end by the motor-blower unit, and

lssupported at its inner end in the opening l2 in the furnace wall.

With the above-described arrangement of the various parts of my improved stoker, it will be apparent that the power mechanism, the burner,

and the source of fuel supply are arranged in` alinement, and that the fuel conveyor shaft extends in a direct line with the stub driving shaft 1B of the transmission mechanism, through the lower part of the burner, and through the fuel supply pipe to the source of fuel supply. It will also be apparent that the ash screw is paralulel with the fuel feed screw, is driven directly from the stub driving shaft of the transmission by a sprocket chain, and operates to discharge the ashes from the ash pit in the direction of the source of fuel supply.

It will also be apparent that both conveyor shafts have, in effect, a floating construction. The coupling 15 by which the feed screw is connected to the stub driving shaft fits somewhat loosely upon the adjacent ends of the connected shaft sections so as to permit a considerable degree of lateral movement in the feed screw. In like manner the otherl coupling members between the different sections of the fuel feed shaft are loosely fitted thereon. `As will be apparent, therefore, the only positive support for the fuel feed screw is that which is provided by its connection with the stub driving shaft. When the stokerr is in operation, the feed screw is supported the fuel feed pipe by the fuel which is being Vdelivered therethrough, also by the self-forming bearing which is produced in the bearing chamber 23 by means of thel powdered fuel which works its way into this chamber and is compressed therein by the rotation of shaft section 36; I have found from experience that a bearing of this character operates with entire satisfacnon and makes possible the elimination of the .metal bearing which has heretofore been regardair chamber 64 and the perforations I9 in the grate, the ashes and other solid products 'of combustion are discharged from the yupper edge of the burner and drop downwardly into the ash pit I2. The ash plates I8 are preferably employed to direct the ashes into the region of the ash screw 45, whereupon they are Adischarged through the ash tube 48, into the' bag 55 supported on the iioor 19, in the manner heretofore described. It will be understood, however, that the ash directing plates 46 are not essential to the operation of the ash removal device inasmuch as the ashes may be permitted to accumulate in the ash pit to a suiiicient extent to bring them within the zone of action of the ash screw. The tapered end I'I of the burner casing facilitates the movement of the ashes to the ash screw.

passageway, a pick-up device in the form of a' funnel 89 is positioned with its outlet end in the -passageway and its inlet end in the air chamber,

side near the lower end thereof, and a conveyor shaft opening in .alinement therewith in the opposite side, a grate supported in said casing and having an opening at its lower end communicating with said inlet opening, and a fuel conveyor pipe connecting said inlet opening with a source of fuel supply, the combination of a conveyor shaft extending through said pipe and projecting outwardly through said'shaft opening, a wire Wound spirally around said shaft said pipe toform a conveyor for feeding fuel through said pipe to said grate upon rotation of saidV shaft, the overall diameter of said conveyor being substantially less Athan the inside diameter of said conveyor pipe, and` power means connected to said shaft for rotatingihe same. l

2. In an automatic `stoker provided with a burner having a fuel inlet opening in one side near the lower end thereof, a hollow boss on said burner; opposite said inlet opening and having a conveyor shaft opening in its outer end, and a fuel conveyor pipe connecting said inlet opening with a source of fuel supply, the combination of a conveyor shaft extending through said pipe and said boss and projecting loosely through said shaft opening, a wire spiral wound around and secured to said shaft within said pipe to form a conveyor for feeding fuel through said pipe to said burner, theV overall diameter of said conveyor being substantially less than the inside l diameter of said conveyor pipe, and means conpreferably projecting in a direction opposite that in which the current of air in the air chamber drawing, the ash removal devicemay be omitted where this is desired for reasons of economy. This may be easily done by reason of the fact that the sole connection between the ash removal device and the other parts of the mechanism is through the bracket 80 which is detachably secured to one of the lateral lugs 'I1 by means of bolts 90. In case the ash removal device is omitted,it is, of course, necessary that ashes be removed from the ash pit .I2 from time to time in order to prevent too great an accumulation therein.

While certain structural forms of the important features of the stoker have been disclosed herein, together with a preferred arrangement of the various parts with respect to one another, it is to be understood that the invention is not intended to be limited to the precise structure and arrangement of parts as shown and described. The above description and the accompanying drawing is therefore to be regarded as illustrative only of the form and arrangement of the various elements of the apparatus, and it is to be understood that the invention is susceptible of other forms and arrangements so long as they come within the scope of the appended claims.

What I desire to claim is:l

l. In an automatic stoker provided with a burner casing'having a fuel inlet opening in one nected to said shaft for rotating the same.

3.V In an automatic stoker provided .with a burner having a fuel inlet opening in one side near the lower end thereof to deliver fuel upwardly therethrough, and a conveyor pipe connecting said opening with a source of fuel supply, the combination of a conveyor shaft extending through said pipe and said opening, a wire spiral wound around and secured to said shaft to form a conveyor for feeding fuel through said pipe upon rotation of said shaft, the overall diameter of said conveyor being substantially less thanthe inside diameter of said conveyor pipe, and means for rotating said shaft.

4. In an automatic stoker provided with a burner having a fuel inlet opening in one side near theA lower end thereof to deliver fuel upwardly therethrough, and a conveyor pipe connecting said opening with a source of fuel supply, the combination of a conveyor shaft extending through said pipe and said opening, a wire spiral wound around and secured to said shaft to form a conveyor for feeding fuel through said pipe upon rotation of said shaft, the overall diameter of said conveyor being substantially less than the inside diameter of said conveyor pipe, propeller means secured on said shaft at said inlet opening to feed the fuel upwardly into said burner, and means for rotating said shaft. 5. In an automatic stoker provided with a burner having a fuel inlet opening in one side near the lower end thereof to deliver fuel upwardly therethrough, and a conveyor pipe connecting said opening withv a source of fuel supply, the combination of a conveyor shaftextending through said pipe and -said opening, a wire spiral wound around and secured to said shaft to form a conveyor for feeding fuel through said pipe upon rotation of said shaft, the overall diameter of said conveyor beting substantially less than the inside diameter of said conveyor pipe, a at spiral flight secured on said shaft at said inlet opening to feed upwardly into said burner and fuel delivered to said opening by said wire spiral, and means for rotating said shaft.

6. In an automatic stoker provided with a burner and a coal conveyor pipe extending between said burner and a source of coal supply, the combination of a shaft extending through said pipe, a spiral of wire closely wound around and secured to said shaft to form a conveyor to feed coal through said pipe to said burner upon rotation of said shaft, the overall diameter of said -conveyor being substantially less than.

the inside diameter of said conveyor pipe, and power mechanism for rotating said shaft.

7. In an automatic stoker provided with a burner and a coal conveyor pipe extending between said burner anda source of ooalsupply, the combination of a iioating shaft extending through said pipe, a spiral of round wire closely Wound around `and secured to said shaft and forming a conveyor to feed coal through said pipe to said burner upon rotation of said shaft, the overall diameter of said conveyor being substantially less than the inside diameter of said conveyor pipe, and power transmitting mechanism in alinement with said pipe for supl porting one end of said shaft and rotating said shaft..

8. In an automatic stoker provided with a burner and acoal conveyor pipe extending between said burner and a source of coal supply, the combination of ashaft extending through said pipe, a spiral of wire of a given diameter closely wound around a section of said shaft adj acent said burner, a spiral of wire of smaller diameter closely wound around the portion of said shaft between said section and said source of supply, said spirals forming a conveyor having an over'- all diameter substantially less than the inside diameter of said conveyor pipe, and means for rotating said shaft.

9.,In an automatic stoker provided with a 4 burner and a coal conveyor pipe extending between said burner and a source of coal supply, the combination of a shaft extending through said pipe, a wire spiral of a given diameter closely wound around a section of said shaft adjacent overall diameter substantially less than the insideA diameter of said conveyor pipe, a at spiral flight secured on said shaft at the delivery end of the` second wire spiral, and means for rotating said shaft.

GEORGE H.V CROCKER.

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