US2126104A - Automatic stoker - Google Patents

Description

Aug. 9, 1938. w. M. FULTON AUTOMATIC STOKER Original Filed 'sef t. 9, 1951 6 Sheets-Sheet 1 gwuento'c U VLMOW, Mann *n/afary.

Aug. 9, 1938. w. M. FULTON AUTOMATIC STOKER Original Filed Sept. 9, 1931 s sheets-sheet 2 hilllil III II Aug. 9, 1938. w. M. FULTON AUTOMATIC STOKER Original Filed Sept. 9, 1931 6 Sheets-Sheet 5 Aug. 9, 1938. w. M. FULTON AUTOMATIC STOKER s Sheet-Sheet 4 Original Filed Sept 9, 1931 ELL W. M. FULTON AUTOMATIC STOKER 6 Sheets-Sheet 5 OriginalFiled Sept. 9, 1931 vAug. 9, 1938. w. M. FULTON AUTOMATIC sTokER 6 Sheets-Sheet 6 Original Filed Sept. 9, 1931 O m w a W mm /v 1 w. w w .M WW ad L 5 a F Q 9 m w 9 m mw 2 V Patented ,Aiug. 9,1938 1 Weston M. Fulton,=Knoxvlllc, Tenn, assignor to W. J. Savage Company, 1110., Knoxville, harm, a

corporation of Delaware Application September 9, 1931, serial ascrsu V Renewed January 4, 1938 v This invention relates to heating plants, and

r more particularly to automatic stokers for burning solid. fuel. 7

Ithas previously been proposed to provide if ll naces burning solid fuel, such as coal or coke,

with fuel magazines or, hoppers which, as long as they are kept supplied with fuel, provide, a continuous, gravity feed of fuel to a burning zone within the furnace to which air is admitted by the 10 usual dampers and through suitable tuyeres, the ashes-being deposited in an ash pit within the furnace whence they may be removed manually. Other stokers have also been provided wherein the fuel is fed mechanically, as by a moving grate or a screw conveyor, and combustion is facilitated by a power driven air blower. Still other forms of automatic heating plants have been suggested wherein fuel is supplied from a'magazine and mechanically fed into a burning chamber, air being supplied under pressure to said chamber through 'tuyere blocks supporting the fuel bed,

and suitable automatic temperature responsive control devices being provided for controlling the supply of current tothe motor which actuates boththe fuel feeder and the air blower.

All of these prior devices, however, possess ob- Jectio'nable features which it is "the object of the present invention to overcome. The earlier type gravity feed magazine furnaces were particularyobjectionable because irregular, holes or cav itieswould burn through the fuel causing it to arch over the cavities and fail to feed down-'- wardly, and there was also often a tendency for smoke to pass upward through the magazine and escape around the edges of the magazine door,

this being especially true when the fuel had fed down low in the magazine to a point where the thickness of the fuel above the burning zone was i very slight. Other difficulties experienced with 40 thistype of furnace included the escape of volatile matter from the fuel and its deposit on and around the magazine door, the clogging of the burning zone with ashes dueto failure to remove them at proper intervals,- the necessity for a strong chimney draft, and the limitation in ca- 55 thickness, this resulting in wide fluctuations in the emciency at which the fuel is burned. When the demand upon the stoker is great, the tendency is for fuelto accumulate in the burner to a depth which is too greatto permit of complete combustion, 0n the other hand, when the demand is slight, the fuel bed has a tendency to become so thin that the amount of air passing through it -is greater than can be consumed by the fuel, and

causes a. cooling effect with consequent loss of heat units' Secondly, in these automatic stokers 10 of the prior art the combustion chamber and tuyeres are located in the fire box of the furnace or heater itself which makes it' difllcult to remove the ashes and clinkers, and also increases the tendency for fine ash to accumulate in the i5 times become clogged by oversize pieces of fuel or other foreign matter, such clogging resulting either in a breakage of some of the parts or in the temporary stoppage of the stoker. Still another serious diflicultywhich has hitherto been encountered with stoklng devices has resulted from a persistent tendency of the coal or other 30 fuel to bridge or arch at the discharge outlet of the hopper. When this arching occurs, no further fuel feeds down into the combustion chamber or conveyor until the arch is broken up.

It is therefore one of the objects of the present 35 invention to provide an automatic, stoker. for solid fuels which is certain and efiicient in operation, simple and rugged in structure, and free from the defects common to devices of this character previously known to the art. Y 40 Another object is to provide a combined auto matic stoker. and furnace fora heating system a matic stoker and furnace wherein the fuel bed is continuously maintained at a. predetermined thickness and air is supplied thereto under pressure on the cross draft-principle.

Still another object is to provide an automatic stoker embodying novel feeding mechanism for 1 Another objectis to provide novel. agitating combustion chamber. 7 I

A further object is to provide an automatic 2 continuously agitating the fuel bed and moving it so as to prevent irregular burning and arching of the fuel, together with novel means for conveying the fuel from the hopper or magazine to the combustion zone.

A still further object is to provide a stoker having a combustion chamber adapted to operate on the cross draft principle, the tuyeres of which are continuously cooled by the heating medium" of the heating system itself.

Another object is to provide an automatic stoker with novel combined manual and automatic adjusting means whereby a predetermined relationship is constantly maintained between the amounts of air supplied ndl fuel fed to the stoker with novel ash disposalmeansof simple,

of the stoker.

means for feelers. of the hopper type which effectively prevent clogging of the feeder due to arching at the outlet thereof -.of the material beingzfeda" a V i A- still further, object is to provide an automatic stoker embodying-a combustion chamber-of novel structure, built-up from a plurality of individual hollow-walled sections."

Still other objects include novel auxiliary thermostatic control for periodically starting and stopping the stoker independently of the normal thermostatic. controls and without heating the building, novel dust trap.

been described and illustrated in the accompanying drawings, it is to be expressly understood that these drawings are for thepurpose of illustration only and are nottobe construed as a limitation of the scope of the invention reference being had for thatpurpose to the appended claims. a

In the drawings, wherein like reference char- 1 acters indicate like parts throughout the several views:

Fig.1 is a front elevation of one embodiment of the presenti vention showing an automatic a steam generator or water stoker connected heater of the-usual type (and which forconvenience will hereinafter. bereferred to by the generic term -boiler") and'provided with-novel; k v

, ment of the fire therein during/short periods of fwarm'weath'er."

automatic thermostatic control means;

Fig. 2 is a side elevation looking front the left a;

at the embodimentofFig. 1;'

Fig. 3 is a vertical sectionalview taken sub stantially on line 3-3 of Fi'g 2;'

Fig. 4' is an elevation of one of theen d elements" making up the sectional combustion chamber of Fig. 3;

Fig. 5 is an end view looking from the left at I the element of Fig. 4;

Fig. 6 is an elevation similar to thatjof Fig. 4

elements of the'v f products of combustion thenj passing through a the provision .of a I Fig. 7 is an end view looking from the left at the element of Fig. 6;

Fig. 8 is an elevation similar to Figs. 4 and 6 of one of the front intermediate elements of the combustion chamber;

Fig. 9 is an end view looking from the left at the element of Fig. 8; V

Fig. 10 is a sectional view taken substantially on line Iii-l0 of Fig.7;

Fig. 11 is a side elevation of Fig. 10;

Fig. 12 is a front elevation of the fuel feeding mechanism of the embodiment of Figs. 1-3;

Fig. 13 is a sectional view taken substantially on line Iii-I3 of Fig. 12;

, Fig. 14 is a top plan view of the fuel hopper of the embodiment of Figs. 1-3;

" Fig. 15 is an isometric view of one of the sliding agitator plates;

Fig. 16 is a horizontal section, with certain parts shown in full, of the fan shown in Fig. 1;

Fig. 1'7 is a sectional view taken on line ll-l'l .of Fig. 16 and turned through 90;

bodiment of Fig. 19;

, 'Fig. 21 is'a sectional view taken substantially on the center line of the stoker shown in Fig. 19;

and

Fig. 22 is a sectional view taken substantially on the line 2222 of Fig. 21.

Referring now to Figs. 1,2 and 3, there is disclosed therein a heating plant or system comprising a boiler and a novel combined automatic stoker and furnace detachably connected thereto, the stoker not only including fuel supply and feeding means but also having a combustion chamber which is exterior of the boiler, thus greatly simplifying the disposal of ashes and reducing the foulingof the heating surfaces and flues of the furnace by fine ash and dust. This I embodiment of the present'invention also includes a novel combustion chamber operating on the cross draft principle and wherein a predetermined thickness of fuel bed is insured at all times, means for utilizing the heating medium of the system for cooling the combustion chamher and preventing fusion of the tuyeres, im-

' proved fuel feeding means for feeding fuel from the hopper to the combustion chamber, novel means within the hopper for preventing arching of the fuel at the outlet thereof. improved ash operation of the stoker for preventingextinguish- In the form shown. the heating plant comprises .a boiler 23 of any desired type and an automatic stoker and furnaceQindicated generally at 24,

the principalelement's of which are a fuel hopper or magazine 25 from which'fuel is supplied to a combustion chamber or burner 26 "a novel fuel feeding mechanism 21, combustion being supported in combustion chamber 26 by air which is supplied under pressure from a fan or blower 28 through an air trunk or wind box 29 totheburning zone 30 of combustion chamber 28, the gaseous conduit 3| into the'interior of furnace 23. In the form shown, furnace 23 is of the hot water or steam type having a water Jacket 32 through which the heating medium circulates and in which it is heated, a supply pipe or conduit 33 leading from the top of water jacket 32 to the radiators orheating devices disposed throughout the enclosure being heated, and a return pipe or conduit 34 connected to water jacket 32 at its lower portion for returning the heating medium thereto. In the embodiment illustrated, conduit 3| of the stoker 24 is detachably connected to and delivers the gaseous products of combustion from combustion chamber 25 into the ash pit 35 of boiler 23', the hot gases then passing upward through 1 and around the heating surfaces 35 of the boiler and exhausting through smoke pipe 31 to the chimney or flue. As is evident from Figs. 1 and 3, the arrangement of an automatic stoker and furnace detachably-connected to a boiler requires very little reconstruction or rearrangement of the boiler parts, it being necessary only to provide a suitable opening 33in the sideof ash pit 35 to receive the end of conduit 3|, and, if desired, to provide the side of ash pit 35 opposite to open- 111E238 with a baille 33, built up of flrebrick or other suitable refractory material, for preventing the hot gases from injuring ash pit housing 43,

and also for deflectingthe hot gases upward into the heating chamber of the furnace.

Referring" now more particularly to the com- ,ponent elements of combined automatic stoker and furnace 24, fuel hopper 25, which is preferably made of sheet iron or other similar material,-is substantially vertical in order that the fuel may feed therefrom by gravity, and is provided with at le'ast two gradually convergent walls 4| and 42 which'form a comparatively restricted outlet 43. At the lower or outlet end of hopper 25, convergent wall 42 is suitably secured in any desired manner to one end of a substantially semicircular housing or casing member 44,

. the other end of which islikewlse secured to the inlet or bottom end of combustion chamber 25. Fuel feeding mechanism 21 is coaxial with semicircular housing member 44, and is provided with .a rotatable drum 45 to the periphery of which convergent wall 4| of fuel hopper 25 is substantially tangent at its lower or outlet end. Combustion chamber 25 is so located that one of its wall's'is also substantially tangent to the periphery of drum 45 of the fuel feeding mechanism, thus providing an annular space 45 between the periphery of drum 45 and housing member 44 into which fuel is fed from outlet 43 of hopper.25, through which it is carried by thefuel feeding means later to be described, andfrom which it is delivered into the inlet 41 of combustion chamber As is shown best in Fig. 3, inlet 41 of combustion chamber 25 is somewhat larger in cross '-section than annular space 45 in order to allow ,the incoming fuel to .become mixed and agitated at this point.

The body of fuelthua fed to combustion chamber 25 is, due to the continuous underfeed from feeding mechanism '21, moved upward throughL said combustion chamber, is burned in "burning zone 33, and finally approaches the outlet or exit 43 of the combustion chamber as ash or clinker, whence it is automatically and continuously removed by novel ash disposal means which, in the form shown, comprise a sheet metal trough 43 which is secured to one of the walls of combustion chamber 25 and in communication with exit 43 thereof, and into which the ashes overflow by gravity. As indicated in Fig. 2, trough 7 43 is downwardly inclined/and is connected at its lower end to a chute 53 which in turn discharges through an opening in a cover 5| into a suitable removable ash can or receptacle 52.

Referring now to Figs. 12 and 13, there are shownthereln in detail the novel fuel feeding means of combined automatic stoker and furnace 24 which are shown somewhat schematically in. Figs.- 1-, 2 and 3. In the embodiment illustrated,

rotatable feed drum 45 is provided at each end with a disc shaped vflange 53, secured thereto in anysuitable manner, between which flanges are housed the bottom or outlet end of hopper 25',

' semicircular housing member 44, and the forward portion of the bottom or inlet endof combustion chamber 25. Flanges 53 are preferably m'ade integral with drum 45 and are provided with outwardly extending central bosses 54 in which are housed outwardly extending stub shafts 55, the

.latter being journalled in suitable bearing bosses" 55 mounted on brackets 51 which are in turn supported by fa large base 53 on which the major portion of the stoker assembly rests. Flanges 53 are also provided with a plurality of inwardly 'projectlng bearing bosses 53 which are circumferentially spaced around the inner faces of said flanges and so positioned with respect to drum 45 that oscillating shafts 53 journalled therein will just clear the inside surface of drum 45. Rigidly secured to each of oscillating shafts 63 are a pair of lever arms 5| to the outer ends of which are pivotally secured the laterally spaced arms 52 of fuel feeding blades orpaddles 53. v In the embodiment shown, four such paddles 53 are provided, and since they extend substantially diametrically across the interior of drum 45, arms 52 must be suitably spaced so as to allow movement of each blade independently of the other. Since, in its fuel feeding position, each blade 53 must extend outwardly beyond the periphery of feeding drum 45 into annular space 45 so as to engage the fuel, suitable longitudinal slots 54 are provided in the periphery of drum 45 through which blades 53 are adapted to reciprocate.

Novel means are also provided for imparting "reciprocating movement to said blades as drum 45 is rotated, said means being especially adapted to make the outward extension of the blades yielding in character in order that breakage or straining of the parts may be avoided should a blade strike unusual resistance, due'to foreign matter in the fuel, during its outward extension, while the retraction of the blades is performed as a positive operation. As shown, oscillating shafts 53 are each extended at one end outwardly As is shown best in Fig. 12, cam rollers 55 are adapted to engage the surface of cam member 53 in successionas drum 45 is rotated in a man-' ner later to be described, and the contour of cam member 53 is such that the travel of each cam roller 55 therealong'serves to rotate-the shaft 53 to which it is connected and thereby, through lever arms 5|, move its associated fuel feeding blade or paddle 63 from its inner retracted position, wherein the end of said blade is within the outer periphery ofdrum 45, outwardly through slot 64, into contact with and through the fuel Which is fed-intoannularspace 48 from outlet 48 of hopper 25 and into engagement with the inner surface of housing member 44. After cam I roller 66 clears cam surface", blade 63 is maintained inits outward position through'its own inertia until it approachestheinlet or entrance to combustion chamber 26. At this time, cam roller 68 contacts a fixed cam member H rigidly secured to bracket 51 of the supporting framework.

;Movement of cam roller 66 along cam surface 1| gives a positive counter-clockwise rotation to shaft 68 and withdraws blade 83 through slot 64 to its fully retracted position within drum 45 just before said blade reaches the inlet to the combustion chamber.

Since cam member 68 ispivotally mounted on arm 61, and although it is normally maintained in a predetermined position by counterweight 89, should the end of blade 63 strike foreign material in the fuel in annular space 46 such'that un- .'As illustrated somewhat schematically in Figs. 1

and 2;an electric motor I2, preferably of the constant speed type, is provided adjacent. the stoker assembly and drives the fuel feeding mechanism through a suitable speed reduction device. As shown, the shaft of motor. 12 is connected to one element of aspeed reduction gear train housed in a casing or housing 13, the output end of said mechanism driving a worm gear 14 which is rigidly mounted on one end of a shaft 15, on the other end of which is secured a worm. I6 which in turn engages a-plurality of ,teeth l l' forming a gear on the periphery of one of flanges 53 of the fuel feeding mechanism, so as to drive drum 45 in a counter-clockwise direction, as viewed in Figs. 1, 3 and 12. It will be obvious that the speed at which fuel feeding drum 45 is rotated is very much slower than that at which motor I2 rotates,

and that. any of the well known types of speed reduction mechanism may be installed in casing 18 in order to obtain this reduction. Such mechanlsm is also preferably provided with 'manually operable, means such as a lever, 18 for changing the gear ratio of the speed reduction mechanism 1 and thereby varying the speed at whichthe fuel feeding drum 45 is rotated. In: thefembodiment shown movement of lever llto'the right, as viewed in Fig. 1,;reduces the specdatiwhich drum 45 is Referring nowto the detailedfst'ructure of'com- \bustion ,chamber 28-, it .will be seen from Figs. 33-11 that this. combustion'chamber or'burner is,

gcther in scriesby a plurality of hollow nipples rotated.

built up from a plurality of hollow sections, preferablyofcast iron, the sections being secured towhich. are screwed into suitable threaded bosses or openings in each section. As shownin Fig. 3, which is aseetional view taken intermediate the ends ofcombustion chamber 2i, eachsection of said chamber intermediate the ends is composed of two pieces, a front piece indicated generally at 19 and shown in detail in Figs. 8 and 9, and a rear piece indicated generally at 88 and shown in detail in Figs. 6, 7, 10 and 11. All of the intermediate sections made up of 1 front and rear pieces 19 and 88 are assembled together in series by suitable hollow nipples 8! which are screwed at each end by means of unitary side sections indicated generally at 83 and shown in detail in Figs. 4 and 5. As shown in Figs. 4 and 5, end

sections 83 are provided with a solid outer wall 84 and an inner wall 85 from which project threaded bosses 82, the space between outer and inner walls 84 and 85 thus providing free communication between all of the openings in bosses 82 for the circulation of the heating medium in a manner later to be described.

End sections 83 are also provided with inwardly projecting ribs 86 which are adapted toabut similar ribs formed on the adjacent intermediate sections of the combustion chamber and to space said sections the proper distance apart so as to permit the flow of air and hot gases of combustion therethrough. For this latter purpose, the front portion of each end section 83 corresponding to front pieces 82 of the intermediate sections is provided with a plurality of V-shapcd projections or lugs 81 of the same height as ribs 86, separated at their bases by suitable spaces 88 which are adapted to act as tuyeres through which the air supplied to the combustion chamber flows. tion 83 corresponding to the front legs of rear pieces 80 of the intermediate sections is provided with V-shaped lugs 89 similar to lugs 88 but with their vertices directed in the opposite direction, between which lugs there are provided suitable spaces 90 which act as tuyeres through which the hot gases of combustion are exhausted from the combustion chamber.

As shown in Figs. 6 and '7, rear pieces 80 of the intermediate sections each comprises a front leg SI and a rear leg 92, both being substantially L-shaped and joined at their upper ends, front leg 8| acting as the rear wall of the combustion chamber and the space 3| between legs SI and 82 forming the exhaust conduit through which the hot gases of combustion pass from the combustion chamber to the boiler 23. Front pieces I! of Similarly, the portion of each end secthe intermediate sections each comprises a single, I

substantially vertical leg 98 which acts as the front wall of the combustion chamber 28. Both front and rear pieces I! and 80 of the intermediate sections are provided with threaded bosses 82, ribs 88, V-shaped lugs 81 and 88 and openings 84 and 9| similar to those already described in con- ,nection with Figs. 4 and 5. As shown in Figs.

' provided for circulating the heating medium of boiler 23 inside of the various sections making up combustion chamber 28 in order not only to cool the elements of this chamber, particularly the tuyeres formed by lugs ll and 88 and openings 88 and 98, but also to increase the efllciency'of the heating plant by thus adding to the heat content In connection with this detailed description of of the heating medium. As shown, one oithe intermediate sections of the combustion chamber is provided with a suitable inlet opening-95 and outlet opening 96 to which are connected suitable inlet and outlet pipes 91 and 98-1eading from and to water jacket 32, respectively. Inlet and outlet openings 95 and- ,96 communicate with the hollow space 64 within legs 9i and 92 of the particular intermediate section concerned, and the heating medium which is thus supplied through pipe 91 and inlet opening 95 circulates inside of all of the intermediate and end sections comprising the combustion chamber through hollow nipples 8i and the circulating space in the end sections 63 between walls 84 and 85. The temperature ofthe parts of the combustion chamber is thereby prevented from running materially above that of the heating medium in boiler 23.

Referring again to Figs. 1, 2 and 3, it will be seen that the space included between legs 93 and it of the front and rear pieces of the intermediate sections provides a combustion chamber of definite size, two of the Opposite walls of which are gradually divergent from the entrance to the exit thereof. Moreover, since the feeding of fuel to combustion chamber 26 by fuel feeding mechanism 21 not only maintains said chamber full of fuel at all times but also moves said body of fuel through said chamber due to its underfeed characteristics, it is evident that the fuel bed thus supplied is of a uniformly increasing, predetermined thickness.

In order that most emcient combustion shall take place within combustion chamber 26, suitable means are provided for supplying air under pressure thereto in a manner'so as to create a cross draft substantially transverse'to the direction ofmovement of the fuel bed therethrough. As shown, and as previously described, V-shaped lugs 81 and openings 66 in front pieces 1d of the:

sections making up the combustion chamber form tuyeres through which air is adapted to be supplied to the burning zone id of the combustion chamber 26. For this purpose, combustion chamber it is provided with a wind box or air trunk 2d communicating with the inlet tuyeres 81, M, which trunk is supplied with air under pressure from a suitable blower or fan 28 through a conduit 69. Blower W is directly connected to and driven by motor if. Wind box 29 may, if desired, be provided with a suitable cover ltd which may be removed whenever desired for V inspection of the air trunk and removal of any fine ash or dust which might collect therein.

v'JE'he hot gases which are produced by combustion within burning zone '36 are exhausted from the combustion chamber through the tuyeres 6d, 96 formed in the" front legs @l of rear pieces W of the sections comprising said combustion chamber, and are conducted through conduit 3i into ash pit 3b of boiler 28 whence they flow upward in contact with the heating surfaces 36 ofsaid boiler and heat the heating medium in the usual manner. legs 6! and 92 are such as to impart a substantial curvilinear velocity to the hot gases in conduit 3! thus increasing the tendency for any fine ash or dust particles which might be entrained in the hotgases to be deposited in ash pit 35 of boiler 23 and on the bottom of conduit 3| formed by the horizontal portion of L-shaped legs 9| whence said. particles can be readily removed through ash pit door 166' of boiler 23 and an auxiliary door |6l in one of side sections 83 of the combustion chamber 26.

It-will be seen that the l'.-shapes of the combustion chamber 26, it will be noted that "a largernumber of outlet tuyeres 83, 96 have been through burning zone 36 due partly to chemical combination and partly to expansion byheat It has also been mentioned that the combustion chamber is enlarged in cross section as itextends upwardly, this construction being preferable in order that the increased thickness of the fuel bed in the upper portion of the combustion chamber will offer greater resistance to the passage of air therethrough and thus force a greater portion of air to pass through thelower portion of the burning zone where the greatest amount of air is required to sustain combustion.

I In stokers of the type described, difflculty is often encountered in properly feeding fuel from the hopper because of a persistent tendency of the fuel to bridge or arch at the discharge outlet thereof, no furtherfuel feeding down out of the hopper when this arching occurs until the arch is broken up. Novel means are therefore provided for agitating the fuel within hopper 2b and therebycontinually breaking up any arch which might be formed adjacent the outlet d6 of said hopper. As shown in Figs. 1, 2, 3, 14 and 15, hopper 8b is provided with a pair of substantially rectangular, smooth surfaced agitator plates I162 'slidably mounted inside of said hopper adjacent the convergent walls dll and t2.

Plates m2 are of substantially the same size as walls dll and d2 of the hopper and their lower edges lie adjacent outlet it, said lower edges being preferably chamfered or sharpened as indicated at .walking beam 116% extends forwardly over the edge of hopper 2b and is pivotally connected to the upper end of a connecting rod M6 the lower end of which is pivotally'secured to a crank pin um carried by a crank arm till secured to an oscillatable shaft M2 journalled in suitable bearings Md secured to the front wall 42 of hopper it, Shaft lid is also provided with a second crank arm Md having a crank pin M5 on which is pivoted the upper end of a connecting rod lit, the lower end of which is pivotally mounted on a crank pin ill carried by a disc lillt, the latter being rigidly attached to the end of a shaft lid forming part of the speed reduction mechanism housed in casing 13. The throw of crank pin ll Ill carried by disc M8 is preferably less than half that of crank pin 5, so that as shaft H6 is slowly revolved from motor 12 through'the speed reduction mechanism, crank pin 6' and its associated shaft 2 are given only an oscillatory movement, which movement is in. turn transmitted to walking beam I65 thereby imparting to agitator plates I62 an alternate reciprocating l movement substantially parallel to the walls of hopper 25 andthe fuel contained therein. This alternate reciprocating motion of plates I62 gives to the fuel within the hopper adjacent outlet 43;

Although, for all ordinary purposes, successin] operation may be obtained with plates I02 which are smooth on both sides, it is within the contemplation of this invention that, where con- 5 ditions require it, plates I02 may be provided with small projections or otherwise suitably roughened on the sides which contact with the fuel in order to increase the frictional engagementtherewith. Also, in some instances where conditions warrant it, one of the two plates shown may be omitted, although best results are obtained by using both, as in the preferred embodiment.

In connection with the fuel agitating means just described, it has been discovered that the same device is equally eflicient for the prevention of arching and clogging of a number of other materials which are normally fed from hoppers by gravity in a manner somewhat similar tothat in which the fuel is fed from hopper 25 in the automatic stoker herein disclosed. It is therefore within the contemplation oi this invention that the invention embodied in agitator plates I02 and their associated mechanism may likewise be utilized in connection with gravity feeders in general, as for feeding grain, chemicals and the like.

Where automatic stokers of the type herein disclosed are installed in heating systems for residences, apartment houses and the like, it has hitherto been the custom to install a temperature or pressure responsive device on the furnace or boiler to operate in conjunction with a thermostat located within the house for controlling the temperature to which the house is heated. Such an installation is diagrammatically illustrated in Fig. 1 wherein a temperature or pressure responsive control device I20 is mounted on top of boiler 23 and subject to the temperature-pressure condition of the heating medium within water jacket 32, said device being ad-' justable for difl'erent temperatures or pressures within the range of operation of the heating system so that when the water or steam attains the maximum temperature or pressure, the

current through an electric circuit I2I in which heated and set for the desired temperature to be maintained therein. When this temperature is reached, thermostat I24 operates to break an electric circuit I25 in which it is connected and, since circuit I25 also controls relay switch I22, stops motor 12 and the stoker. When the temperature at thermostat I24 drops slightly, circuit I26 is again closed and the stoker again started.

With this installation, the main supply circuit I25 to motor I2 of the stoker is controlled by both regulator I20 and thermostat I24 in such a manner that when either or both of said devices 10 have operated to open their respective circuits,

motor I2 is stopped and the stoker is not opert lxso as .to feed iuel and air to the combustionchamber. By this means, the heating medium within boiler 23 is prevented from reaching an excessive temperature or pressure at times,

such as during very cold weather, when long continuedoperation of the stoker would raise within the enclosure being heated, with the re-' sult that thermostat I24 keeps the stoker shut down during this entire period of time and the fire in the combustion chamber becomes extinguished because of lack of additional fuel and air over this long period of time. This spell of warm weather then terminates in a cool wave with the result that thermostat I24 starts-the stoker but, since there is nothing to cause ignition of the fuel in the combustion chamber, fuel is consequently fed into the burner, is unburned and no heat is generated. In order to cure this defect, novel means are provided by the present invention for controlling the operation of the stoker independently of regulator I20 and thermostat I24, and thereby preventing extinguishment of the fire in combustion chamber 26 during short periods of warm weather.

As shown, a third regulator I26 of any desired construction is installed in return line 34 of the heating system, with a temperature sensitive bulb I21 directly exposed to the heating medium in return line 34. An electric circuit I28 leads from regulator I26 to relay switch I22 and is so connected as to operate said switch independently of circuits I2I and I25. Regulator I26 is calibrated to operate at a temperature materially below that at which regulator I20 is set, and its electrical connections to relay switch I22 are such that it will start motor I2 and stoker 24 when the temperature of the heating medium reaches this low point even though regulator I20 and thermostat I24 have operated to break their respective circuits I2I and' By way of example, it may be stated that, on a steam boiler, regulator I26 may be set to operate at a temperature slightly below that of steam, as at 180 F, With regulator I26 set at this low temperature, a period of warm weather would cause thermostat I24 to stop the stoker, but when the water in boiler 23 has cooled down to 180 F., regulator I26 would operate to complete the circuit to motor I2 and to start the stoker, and would cause it to operate for a short period of time until the temperature of the water in the boiler rises slightly above 180 F., whereupon regulator I26 would operate to stop the stoker until the temperature ,of the heating medium again fell below 180 F. This causes an intermittent operation of the stoker for short periods of time and prevents total extinguishment of the fire in the combustion chamber, yet no heat is supplied to the enclosure being heated since the water in the boiler is maintained below the boiling point and no steam is generated. In a hot water heating system, regulator I26 may be set to operate at a temperature only slightly above any anticipated outdoor temperature, for example F. This low setting is likewise maintained in hot air systems. By this means the fire in the combustion chamber of the stoker is kept alive for a substantial period of time even though the outdoor temperature is sufllciently high to' .always in readiness, for regular'operation when- I ever the weather turns cool.

Although various means'have hitherto been 3 provided for regulating the rate at which fuel is fed into the burner of an automatic stoker, and although it is 'also common practice to provide some manual control means for regulating the amount of air admitted to the burner, in those stokers hitherto known the control of the fuel feed is separate and distinct from the control of the air supply, and it has been left to the operator to adjust these as best he can. This often results in an improper balance between the air admitted and the fuel fed to the combustion chamberwith a consequent inefficiency in the operation of the stoker. Novel means are therefore provided in the present invention for overcoming thisobjection by combining with the fuel feed and air supply adjusting means, an automatic connection whereby when the relative amounts of air and fuel fed have been once ad- :lusted, any change in the adjustment of one will automatically change the other by the proper amount.

As shown in Figs. 1 and 16, fan or blower ll is provided with a casing lid which is reduced in diameter at oneend and provided with an axial opening therein to serve as the air inlet or supply ill to said blower. Fitting over. and around the reduced end of casing ill forming air inlet ill is a cup-shaped cap member ill having a rearwardly extending stem Ill which is slidably'mounted in a boss I33 formed integrally with a pair of supporting arms ill which are suitably secured to the larger portion of easing ltd of blower El. Cap member ill is also provided with a lug lit to which is pivotally connected one end of asuitable connecting rod ill the opposite end'of which is pivotally secured to the lower end of regulating lever it of the speed reduction mechanism housed within easing ll.

As previously mentioned, movement of lever ll to the right, as viewed in'Flg.

ll, and, due to the operative connection between the lower end of said lever and cup member it i it v is evident that such movement will also move said cup member to the left, as viewed in Fig. l, and decrease the effective size of the air inlet llll to blower ld,.'and hence decrease the amount of air supplied thereby to combustion chamber 2t. Suitable manual adjusting means, such as a turn buckle ll'l, is also provided. in connecting rod it for manually adjusting the position of cap member ill at any given position of speed regulating lever ll. Once this adjustment is properly made I thereby- Similarly, a movement of lever I8 to the left increases the rate of fuel feed and automatically pushes cup member I3l to .the right thereby increasing the amount of air supplied to the blower.

1, decreases the a speed of operation of the fuel feeding mechanism By'this means the proper ratio between air supplied and fuel fed to combustion chamber 26 is automatically maintained under all conditions, and a high efficiency of combustion is obtained.

Suitable means are also-provided by the present invention for reducing or eliminating the noise which is normally produced by the high speed moving parts and the passage of the air through the blower of automatic stoker installations of the type herein disclosed. As shown in Figs. 1, 2, l6 and 17, the noise due to the moving parts of electric motor I2, blower 28 and the speed reducing mechanism housed in casing I3 is deadened by mounting these devices upon an individual base l38 which is entirely separate and distinct from the main stoker base 58, and by supporting said base I38 upon a plurality of coil springs I39 or other suitable resilient supports, said springs resting upon a suitable asbestos base MI] on the furnace room floor. In order to permit free vibration of base I38 without interfering with-the stoker drive, shaft It which transmits the driving energy from the speed reduction mechanism in casing I3 to the fuel feeding mechanism ll may be provided with a pair of suitable flexible couplings Ml of any'desired construction.

The noise of. the moving parts of blower 2b is further deadened by constructing blower casing lid with double walls and an air space therebetween. As shown best in Figs. 16 and 17, casing ill comprises an outer wall l ll which is preferably made of hard fiber or other non-resonant material, an inner wall ill secured in any desired manner to outer wall Ill and preferably made of metal, and a dead air space ill between said walls. Cap member lll' may also be provided with a double wall similar to that described for casing lid.

in order to deaden the noise caused by the flow of air through blower ll, the overlapping arrangement of cap member lit and the reduced portion of easing lid is provided in order to make the inlet passageway to the blower a tortuous path as indicated by the arrows in Fig. 16. By this arrangement, the whistle which is ordinarily produced by the inrushing air to a blower is practically eliminated. A further improvement which .inthe provision of a short bellows-shaped section ill of flexible, non-resonant material, such as rubber, leather or other similar fabric, interposed in conduit ll which conducts the air suppliedby blower it to wind box or air trunk 29. With this arrangement, the hum of motor It and the movement of the gears in housing id is silenced by the flexibility of springs ill, while the roar of fan or blower it is deadened by the sound deadening walls of easing ill, and by the tortuous inlet passageway which the air must travel in reaching the blower. Flexible bellows section ill also permits a free vibration of the high speed moving parts wlthoutconducting any sound to the stationary parts of the stoker.

Although it will be evident from the preceding description how the various elements of the present invention function, the operation of the embodiment shown in Figs. 1-17 may be summarized as follows: Assuming that fuel hopper is filled with fuel, and that the temperature or pressure conditions of the enclosure being heated and the heating medium are such that relay switch I22 is in position to close the main supply circuit I23: to electric motor I2, said motor will be driving fuel feedingmechanism 21 through the speed reduction mechanism, and will be directly driving decreases the noise produced by the blower lies 7 blower '28 for supplying air to the combustion chamber 25. Fuel is fed from hopper 25 by. 7

gravity through outlet 43 and into annular space 46 between housing 44 and drum 45. Should there be any tendency for the fuel to arch or clog adjacent outlet 43, agitator plates I02 which are being alternately reciprocated through the driving connections from shaft N8 of the speed reduction mechanism will act to break up any such arch or to prevent its formation. The fuel which is fed into annular space 46 is engaged by paddles 63 as feeding drum 45 is rotated in a counterclockwise direction, said paddles or blades being alternately extended and retracted beyond and within the periphery of drum 45 by the action of cam members 66 and II. Should any blade 63 encounter unusual resistance to its outward extension due to foreign matter in the fuel, cam member 66 will oscillate about its pivot to allow blade 63 to ride over the obstacle until it reaches a point where it can find its way through the less resisting body of fuel and assume its fully extended position in contact with the interior surface of housing 44. The fuel is thus carried around through annular space 46 by blade 63 and is discharged upwardly into inlet 41 of combustion chamber 26, the enlargement of said inlet over the size of annular space 46 permitting the incoming fuel to become mixed and agitated at this point.

The fuel is then fed upwardly within combustion chamber 26 due to the continuous feed of additional fuel below it, and gradually progresses through burning zone of the combustion chamber where it unites with the draft of air which is being blown, transverse to the direction of movement of the fuel body, through inlet tuyres 81, 88 from air trunk 29 to which it is supplied by blowers 28. The hot gaseous products of combustion are exhausted through outlet tuyres 89, 90 into conduit 3| whence they pass into ash pit v3!: of boiler 23 and circulate upwardly therefrom in contact with the heating surfaces 36 of said boiler, finally escaping through smoke pipe 31 to the flue or chimney. After passing through burning zone 30 and being completely consumed, the fuel reaches the upper portion or exit 48 of combustion chamber 26 as ash or clinker and gradually overflows by gravity into ash discharge trough 49 whence it passes through chute 50 into ashcan 52. In the meantime, the tuyeres and other parts of combustion chamber 26 have been cooled and maintained at a temperature not materially higher than that of the heating medium within boiler 23 due to the circulation of said heating medium through the hollow walls of the sectional elements making up said combustion chamber.

The operative connection between regulating lever I8 of the speed reduction mechanism and cap member I3I covering the air inlet to blower 26 insures that at all times the proper ratio of fuel fed and air supplied to the combustion chamber is automatically maintained. Likewise, the resilient, independent mounting of motor I2, blower 26 and the speed reduction mechanism greatly decreases .the noise caused by the high speed moving parts of said devices, as does the double walled casing of the blower, the tortuousshaped inlet passageway thereto and the flexible bellows-shaped section I45 interposed in conduit 69.

Should the enclosure being heated reach the desired degree of temperature, or should the temperature or pressure of the heating medium rise to a predetermined maximum point, thermostat I24 or regulator I 20 will act to open the supply circuit I23 to motor I2 and stop the stoker until such time as the temperature within the enclosure or in the heating medium falls below that at which said regulating devices are calibrated. Should a period of warm weather occur during the time'when the automatic stoker is in operation, such that it is not required that the furnace heat the enclosure, auxiliary regulator I26 will function to intermittently start and stop the stoker so as to prevent complete extinguishment of the fire within the combustion chamber 26.

In the usual types of stoker installations where the combustion chamber is located within the fire box of the furnace, it is a common defect that the blast of air from the fan or blower carries foreign particles of ash and dust up into the fiues and smoke pipes of the furnace, covering them with a coating which reduces the heating efliciency of the installation, and in some cases blows this dirt through the chimney and discharges it on the house tops and surrounding lawns. The embodiment of the present invention illustrated in Figs. 1-17 obviates this defect to some extent by virtue of the fact that the combustion chamber is located outside of the boiler and the shape of the conduit through which the hot gases pass on their way to the boiler is such as to cause most of the fine ash and dust to be deposited in the ash pit of the boiler.

Referring now to Fig. 18, there is disclosed therein still another means for reducing or eliminating this defect. The stoker installation disclosed in Fig. 18 is substantially the same as that previously described, although several features have been omitted from the illustration in the interest of simplicity, with the exception that legs 9| and 92 of the rear pieces of the intermediate sections making up combustion chamber 26 are not only provided with spacing ribs 66 around the outside edges thereof, but also have additional ribs I46 of the same height as ribs 66 around the inner edges thereof so as to form a restricted passageway or conduit I41 for the gaseous products of combustion. The bottom horizontal portion of each leg 9| is also provided with a pair of upwardly extending horizontally spaced partitions I46 and I49, the space between partitions I48 and the vertical parts of legs 9| forming a main ash or dust trap I56, while the space between partitions land I46 forms a secondary trap I5I. Because of the fact that passageway I" is restricted in cross sectional area by ribs I46, the hot gases of combustion exhausting through tuyeres 69, 90 attain a relatively high velocity in passing downwardly through this passageway, and since the fine particles of ash and dust entrained in said gases are heavier than the gases, they have a tendency to continue a vertically downward course and to be deposited in main trap I50. Any residual particles which may be carried beyond trap I56 will be deposited in secondary trap I5I. As the hot gases turn the curve in passageway I41 formed by the L portion of leg 92 at high velocity, centrifugal force aids in separating the heavier ash and dust particles from the hot gases and in depositing them in traps I60 and lil. The ash and dust collected in traps I66 and Iii may be periodically removed through a suitable door in the side of combustion chamber 26 similar to that indicated at IIII in Fig. 1. The almost negligible quantity of dust which escapes traps I50 and lil is deposited in ash pit 36 of boiler 23 whence it may be removed through the ash pit door as desired.

"wall I63 of the combustion chamber. chamber I66, the gaseous products of combus- Although in the preferred form of the invention, the fuel is fed into a substantially vertical combustion chamber, it will be understood that, if desired, the combustion chambenmay be inclined at any desired angle from the vertical without departing from the invention, as in the case of very small residential installations where it is preferable that the combustion chamber lie horizontally. Figs. 19-22 disclose such an installation wherein the combustion chamber is substantially horizontal and the air supplied thereto provides a substantially vertical, downward cross draft. The elemental structure and principles of operation of this latter embodiment of the invention are fundamentally the same as in the embodiment of Figs. 1-17, although various minor improvements such as the hopper agitating means, noise deadening means and the automatic fuel feed and air supply regulating means have been omitted from the drawings in the interest of simplicity, and may be omitted in the actual installation. if desired.

As shown, fuel-is fed from a hopper 25 by fuel feeding means 21 as previously described, to a substantially horizontal combustion chamber I52. The driving means for fuel feeding mechanism 21 is slightly difl'erent from that previously disclosed in that the speed reducing mechanism housed within casing 13, which is driven by motor 12, is provided with a forwardly extending shaft I53 on which is secured a drive pulley I66 which is connected by a suitable belt I55 with a similar pulley I56 secured to the driving shaft 1 of a worm I56, the latter engaging and driv ing a worm wheel I59 which is secured to one of stub shafts 55 of the fuel feeding mechanism. Worm I53 and shaft I51 are suitably journalled in bearing brackets I66 secured to one of a pair -.of legs I6I which support hopper 25 and fuel feeding mechanism 21. v

Combustion chamber I52 is of substantially the same built-up construction as chamber 26 previously described, having a pair of opposite, gradually divergent walls I62 and I63 which form a combustion chamber of gradually increasing cross sectional area from its entrance to its -exit, the upper wall I62 being provided with a plurality of inlet tuyeres I66 and the lower wall I63 having a larger number of similar outlet tuyeres I65. the construction of said tuyeres being similar to those of the preceding embodiments:- -Air is supplied under pressure to inlet tuyeres' I66 from a blower 23 through conduit 66 and an air trunk' or wind box 26, is forced downwardly through the moving body of fuel in burning zone 36 in a substantially vertical direction, and the products of combustion are exhausted through tuyeres' I66 into a chamber or conduit I66 formed below tuyeres I66 by an offset portion I61 of bottom From tion are conducted at right angles through a conduit I66 into the ash pit 35 of the boiler. As will be seen from'Flg. 22, the bottom of chamber I66 is lower thanthat of conduit I66 thereby providing an ash or dust trap I66 in which fine particles of ashor dustare deposited from the hot gases on their way to the boiler,

' said ash and dust being removed when desired through a suitable door I16 in the side of cham-v ber I66. Conduit I66. is also provided at its discharge end in ash pit v35 with a downwardly curved baflle plate "I which deflects the hot gases downward as they enter the ash pit, the curvilinear velocity thus imparted to said gases to separate the fine particles of ash and dust from the hot gases and to deposit said particles in the bottom of ash pit 35.

The walls of combustion chamber I52 are made hollow in'a manner similar to that previously described in order that they may be cooled by the circulation therein of the heating medium from the boiler supplied thereto through a suitable pipe or conduit 91 and returned therefrom to the boiler through a similar pipe 98.

Secured to the outlet end 66 of combustion chamber I52 is a substantially J-shaped ash pit creating a centrifugal force which further tends casing or housing I12, preferably made of sheet metal, provided at its bottomportion with a suitable drawer I13 into which the ashes overflow by gravity from the outlet end of combustion chamber I52. As shown in Fig. 19, drawer I13 is provided with an outer lid I16 which closes tight around the opening in ash pit housing I12 to prevent escape of air therethrough. Ash drawer lid H6 is also provided with a suitable handle I15 for withdrawing it from housing I12 for the purposes of emptying the ashes. Ash pit housing I12 is also provided with a weighted check damper i16 pivoted thereto at its upper end as at I11, said damper tending to retard the flow of ashes so that the fuel bed will be maintained compact and the formation of cavities in the hot burning zone 36 will be prevented.

Suitable means have also been provided for preventing the escape of smoke and other gaseous products of combustion back through the fuel supply and out of hopper and through the ashpit and out of housing I12. As shown, a pipe or conduit I16 is connected between wind box 26 and the inlet 61 to the combustion chamber, and an additional pipe I19 between wind box 29 and a point within ash pit housing I12 adjacent the exit 68 of combustion chamber I52. By thus leading air from wind box 29 to points adjacent the entrance and exit of the combustion chamber, the air pressure at these points is equalized with that in burning zone, 36 and any tendency for smoke or other gaseous products of combustion to escape in these directions is eifectively prevented. v

, It will be understood that in any installation where the combustion chamber is inclined at an angle to the vertical, as in the embodiment just described, fixed cam H of the fuel feeding mechanism is suitably located so that blades 63 are retracted within fuel feeding drum 65 at the proper time, just as they-approach the discharge end of annular space 66.

Although the automatic stokers embodying the present invention have been illustrated as connected to a steam or hot water boiler, it will be understood that the invention is equally applicable to any other type of heating plant. For instance, in the case of a hot air furnace, the connections are substantially the same as those illustrated with the exception that pipes 61 and 66 leading from water jacket 32 of the boiler to the hollow walls of the combustion chamber would be replaced by air pipes, and a rapid cir: culation of air would be maintained through the air chamber of the furnace and the hollow walls of the stoker combustion chamber by means of a power driven fan of the type now generally heated. I There is thus provided by the present invention a new and improved form of heating plant embodying an automatic stoker having a combustion chamber located exteriorly of the boiler and operating on the cross draft principle, thereby providing an installation which is not only efficient and dependable in operation, but also successfully solves the various problems incident to installations of this character and obviates the defects common thereto. Not only has the disposal of ashes and clinker been greatly facilitated by locating the combustion chamber outside of the boiler, but novel means have also been provided for automatically discharging said ashes and clinker from the combustion chamber, and for entrapping the fine particles of ash and dust which become entrained in the gaseous products of combustion and would otherwise be carried into the boiler and deposited on the heating surfaces and in the flues and smoke pipes thereof. The present invention also provides novel fuel feeding mechanism which permits a yielding of the moving parts should foreign obstructions be encountered in the fuel being fed, and thereby avoids breakage or straining of the mechanism, and includes novel agitating means for' preventing the formation of arches in the fuel of the hopper at the comparatively restricted outlet thereof. As has previously been mentioned, this latter improvement is equally well applicable to any other form of gravity feeding hopper means where the material is subject to this same arching or clogging tendency.

Due to the novel construction of the combustion chamber provided by the present invention, a

fuel bed of predetermined thickness is constantnot only preventing damage to these parts of the stoker which are exposed to high temperatures,

but also increasing the heating efficiency of the heating plant as a whole. Novel means have also been provided whereby a predetermined relationship is automatically maintained between the amounts of air supplied and fuel fed to the combustion chamber, said means including a manual adjustment for the air supply independent of the fuel feed.

A further improvement provided by the present invention consists in the provision of novel auxiliary thermostatic control means for periodically starting and stopping the stoker independently of the normal controls, and without heating the enclosure, in order that the extinguishment of the fire in the combustion chamber may be prevented during short periods of warm weather which may occur during the time when the stoker is in operation. Also, novel means are included for deadening the noise produced by the blower and other high speed parts of the stoker apparatus and for preventing transmission of these noises to other parts of the heatingplant. The stoker installation thus provided is adapted for use with any of the usual types of heating plant, large or small, and is readily and inexpensively installed with a minimum of reconstruction and rearrangement work.

Itwillbe obvious that the invention is not limited to the forms described and illustrated in the accompanying drawings, but is capable of a variety of mechanical embodiments. For example, any desired form of fuel hopper may be substituted for the specific form shown and described, and any suitable forms of speed reduction mechanism may obviously be employed for driving the fuel feeding mechanism. Likewise, it will be understood that any known means of automatic control of the heating plant may be substituted for the system described and illustrated. Moreover, features illustrated only in conjunction with one embodiment may be used in other embodiments, and various combinations can be made of the several features illustrated and described,

within the present invention. Various other changes, which will now appear to those skilled in the art, may be made in the form, details of construction and arrangement of the parts without departing from the spirit of the invention, and reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A combined automatic stoker and furnace unit comprising a fuel hopper, a combustion chamber extending upwardly at an acute angle thereto, means intermediate said hopper and said combustion chamber for feeding fuel from said hopper to said combustion chamber and for moving the body of fuel upwardlythrough said combustion chamber, means for providing a cross draft of air from one side of said combustion chamber to the other substantially transverse to the direction of movement of the fuel body therethrough for supporting combustion therein, and means for conducting the gaseous products of combustion therefrom.

2. In an automatic stoker, a fuel hopper, an

elongated, stationary combustion chamber, means between said hopper and said combustion chamber for feeding fuel from said hopper to said combustion chamber and for moving the body of fuel thus supplied longitudinally through said chamber, tuyeres disposed in opposite walls of said combustion chamber. means for supplying air to the moving body of fuel through the tuyeres in one wall of said chamber, and means for exhausting from said chamber the gaseous products of combustion through the tuyeres in the opposite wall, whereby the draft in said chamber is substantially transverse to the direction of movement of said body of fuel.

3. In a heating plant, a fuel supply, a combustion chamber having gradually divergent walls from the entrance to the exit thereof, the walls of said chamber providing a burning zone of definite cross sectional area and volume, means for positively feeding fuel from said supply to said combustion chamber and for maintaining said chamber full of fuel whereby a fuel bed of predetermined thickness is provided, and tuyre means disposed in the opposite divergent walls of said chamber for providing a draft which throughout the combustion zone is across the direction of movement of fuel through said chamber.

4. In a heating plant, a fuel supply, a combustion chamber having gradually divergent walls from the entrance to the exit thereof, means for positively feeding fuel from said supply to said combustion chamber and for maintaining said chamber full of fuel whereby a fuel bed of predetermined thickness is provided,

tuyres disposed in the opposite divergent walls of said chamber, means for supplying air to the fuel bed through the tuyeres in one of said divergent walls, and means for exhausting from said chamber the gaseous products of combustion through the tuyeres in the, opposite divergent wall, the cross sectional area of said exhaust tuyeres exceeding that of said supply tuyeres.

5. In a heating plant, a fuel supply, a combustion chamber having gradually, divergent walls from the entrance to the exit thereof, means for positively feeding fuel from said supply to said combustion chamber and for maintaining said chamber full of fuel whereby a fuel bed 'of predetermined thickness is provided, tuyeres disposed in the opposite divergent walls of said chamber, means for supplying air to the fuel bed through the tuyeres in one of said divergent walls, means for exhausting from said chamber the gaseous products of combustion through the tuyeresin the opposite divergent wall, the cross sectional area of said exhaust tuyeres exceeding that of said supply tuyeres, and ash removal means disposed adjacent the exit end of said chamber into which the ashes overflow by gravity.

' 6. In a heating plant, a fuel hopper, a combustion chamber having approximately vertical walls, means for feeding fuel from said hopper to said chamber and for moving the body of fuel thus supplied vertically upward through said chamber, tuyere means disposed in opposite walls of said chamber, means for supplying air to the fuel body through the tuyeres in one of said .gent walls of said chamber, and means for creating a cross draft through said moving fuel body from one of said tuyere means to the other.

8. In a heating plant, a fuel hopper, a combustion chamber having approximately vertical walls, means for feeding fuel from said hopper to said chamber and for moving the body of fuel thus supplied vertically upward through said chamber, tuyere ineans disposed in opposite walls of said chamberifor providing a cross draft transversely from one side of said moving fuel body to the other, and ash removal means disposed adiacent the upper end of said chamber into which the ashes overflow by gravity.

9. In a heating plant, a fuel hopper, a com- -bust'ion chamber havingapproximately vertical walls, means for feeding fuel from said hopper to said chamber'and for moving the body of fuel thus supplied vertically upward through said -chamber',tuyere means disposed in opposite walls of said chamber for creating a cross draft through said moving fuel body; and means for removing the ashes from said chamber com prising a downwardly inclined troughadjacent to and in communication with the upper end of said chamber into which the ashes overflow, and a chute connecting with the lower end of said trough and discharging into a removable ash receptacle.

10. In a heating plant, a fuel hopper, an elongated, stationary combustion chamber having approximately horizontal walls, means for feeding fuel from said hopper to said chamber and for moving the body of fuel thus supplied hori- 'zontally and axially through said chamber, and tuyere means disposed in a pair of opposite walls of said chamber for creating a cross draft "through said moving fuel body.

11. In a heating plant, a fuel hopper, anelongated, stationary combustion chamber having approximately horizontal walls, said walls being gradually divergent from the entrance to the exit of said chamber, means for feeding fuel from said hopper to said chamber and for moving the body of fuel thus supplied horizontally and axially through said chamber, and tuyere means disposed in a pair of opposite divergent walls of said chamber for creating a cross draft through said moving fuel body.

12. In a heating plant, a fuel hopper, an'elongated, stationary combustion chamber having approximately horizontal walls, said walls being gradually divergent from the entrance to the exit of said chamber, means for feeding fuel from said hopper to said chamber and for moving the body of fuel thus supplied horizontally and axially through said chamber, tuye're means disposed in a pair of opposite divergent walls of said chamber fuel body, and ash removal means disposed adjacent the exit end of said chamber into which the ashes overflow by gravity.

13. In a heating plant, a fuelsupply, a com bustion' chamber, means for positively feeding fuel from said supply to and through said combustion chamber, inlet andoutlet tuyeres disposed in opposite walls of said chamber for creating across draft through the fuel, a furnace, and conduit means connecting saidv outlet tuyeres withthe interior of said furnace. 1

14. In a heating plant, the combination with a boiler of a combined stoker and combustion chamber'detachably mounted in communication therewith, said combined stoker and chamber including means for positively feeding fuel to and maintaining a fuel bed of predetermined thickness in said chamber, means for creating a cross draft by'applyingair to one side of said fuel bed, and means for conducting the gaseous products of combustion from the opposite side of said chamber to the interior of said boiler.

15. In a heating plant, the combination with a boiler of a combined stoker and combustion chamber detachably mounted in communication therewith, said combined stoker and chamber ineluding a fuel hopper, a combustion chamber laterally disposed with respect to said hopper and having gradually divergent ,walls from the enchamber exterior of said boiler, conduit means for" conducting the gaseous .products of combustion from said chamber to the interior of said boiler, said conduit means including means for directing said gaseous products at a relatively highvelocity in a curvilinear path, and a dust trap wherein 75 fine particles of dust and ash entrained in said gaseous products are deposited by centrifugal force.

17. In combination, a boiler, a combustion chamber exterior of said boiler, conduit means for conducting the gaseous products of combustion from said chamber to the ash pit of said boiler, a dust trap associated with said conduit means for collecting dust and fine ash blown through the combustion chamber, and bafiie means at the delivery end of said conduit means for imparting to said gaseous products of combustion a relatively high curvilinear velocity toward the bottom of said ash pit and thereby depositing therein additional quantities of dust and fine ash entrained in said gaseous products.

18. In an automatic stoker for solid fuels, a fuel hopper, a combustion chamber, and means for feeding fuel from said hopper to said chamber comprising a rotatable drum interposed between the exit of the fuel hopper and the entrance of the combustion chamber, a plurality of blades carried by said drum, means for yieldingly extending said blades beyond the periphery of said drum at the exit of said hopper to engage the fuel and carry it to the entrance of said chamber, and means for positively withdrawing said blades within the periphery of said drum at the entrance of said chamber.

. 19. In an automatic stoker for solid fuels, a fuel hopper, a combustion chamber, and means for feeding fuel from said hopper to said combustion chamber comprising a rotatable drum interposed between the exit of the fuel hopper and the entrance of the combustion chamber, a plurality of blades pivotally mounted within said drum, a plurality of slots in the periphery of said drum through which said blades are adapted to reciprocate, a roller operatively associated with each blade, a cam adapted to be engaged by said rollers in succession and to force said blades outwardly through said slots and into engagement with the fuel when adjacent the exit of said hopper, said cam being oscillatable around a fixed pivot and balanced by a counterweight to permit a yielding extension of said blades, and a fixed cam adapted to be engaged by said rollers and to positively force said blades inwardly through said slots when adjacent the entrance of said chamber.

20. In an automatic stoker for solid fuels, 9. fuel hopper, a combustion chamber, and means for feeding fuel from said hopper to said chamber comprising a rotatable drum interposed between the exit of the fuel hopper and the entrance of the combustion chamber, a plurality of shafts journalled within said drum adjacent the periphery thereof, a lever rigidly secured to each of said shafts, a fuel feeding blade pivotally connected to each of saidlevers, an arm rigidly secured to each of said shafts, a roller mounted on each of said arms, a plurality of slots in the periphery of said drum through which said blades are adapted to reciprocate, a cam adapted to be engagedby said rollers and to force said blades outwardly through said slots and into engagement with the fuel when adjacent the exit of said hopper, said cam being osclllatable around a fixed pivot and balanced by a counterweight to permit a yielding extension of said blades, and a fixed cam adapted to be engaged by said rollers and to positively force said blades inwardly through a said slots when adjacent the entrance of said chamber.

21 1In an automatic stoker of the type embody-' to said chamber, a constant speed motor, means for driving said fuel feeding means from said motor and a blower directly connected to said motor for supplying air to said combustion chamber, the combination of a housing for said blower having an opening therein to admit air to said blower, a cap member mounted adjacent said opening and movable with respect to said housing, the space between said cap and housing providing an air inlet passage to said blower, means for moving said cap relative to said housing to vary the amount of air supplied to said blower, means for varying the speed at which said fuel feeding means is driven by said motor, and means operatively connecting said last two mentioned means for movement together whereby the amount of air supplied by said blower to said combustion chamber is regulated in proportion to the amount of fuel fed thereto by said fuel feeding means.

22. In an automatic stoker, a combustion chamber, means for feeding fuel into the entrance of said chamber, means for removing ashes from the exit of said chamber, inlet and outlet tuyeres in opposite sides of said chamber,

.means for supplying air under pressure to the inlet tuyeres, an exhaust passage communicating with said outlet tuyeres, and conduit means leading from said air supply means to points adjacent the entrance and exit of said combustion chamber whereby the air pressure is equalized on both sides thereof.

23. In an automatic stoker, a combustion chamber, a fuel supply passage at one end of said chamber, an ash discharge passage at the other end of said chamber, tuyres in opposite sides of said chamber intermediate said fuel supply and ash discharge passages, an air trunk connected with the tuyeres in one of said sides of said chamber for producing a cross draft therein, an exhaust passage communicating with the tuyeres in the opposite side of said chamber, and conduits leading from said air trunk into both said fuel supply and ash discharge passages whereby the escape of gaseous products of combustion through said passages is prevented.

24. A combined automatic stoker and furnace unit comprising a fuel hopper, a combustion chamber in communication therewith, means intermediate said hopper and said combustion chamber for positively feeding the fuel into and through said combustion chamber, inletand outlet tuyeres in opposite sides of said combustion chamber, a conduit for supplying air to said inlet tuyeres and thence to said fuel bed in a direction transverse to the direction of movement of the fuel therein whereby a fuel bed of predetermined thickness is maintained, a conduit for leading the products of combustion from said outlet tuyeres,

a blower for forcing air through said tuyeres and fuel bed, and a motor for driving said feeding means and said blower, all of said elements constituting a self-contained unit adapted to be mounted exteriorly of a boiler'and to be detachably connected thereto.

25. A combined automatic stoker and furnace unit comprising a fuel hopper, a combustion chamber in communication therewith, means intermediate said hopper and said combustion chamber for postively feeding the fuel into and through said combustion chamber, inlet and outlet tuyeres in opposite sides of said combustion chamber, a conduit for supplying air to said inlet tuyeres and thence to said fuel bed in a direction transverse to the direction of movement of the maintain said chamber full of fuel and thereby fuel therein wherebyza fuel bed of predetermined thickness is maintained, a conduit for leading the products of combustion from said outlet tuyeres, a blower for forcing air through said tuyeres and fuel bed, and means associated with said combustion chamber for removing ashes from the end of said chamber, all of said elements constituting a self-contained unit adapted to be mounted exteriorly of a boiler and be detachabiy connected thereto.

26. Acombined automatic stoker and furnace unit comprising a fuel hopper, a combustion chamber in communication therewith, means intermediate said hopper and said combustion chamber for positively feeding the fuel into and through said combustion chamber, inlet and outlet tuyeres in opposite sides of said combustion chamber, a conduit for supplying air to said inlet tuyeres and thence to said fuel'bed in a direction transverse to the direction of movement of the fuel therein whereby a fuel bed of predetermined thickness is maintained, a conduit for leading the products of combustion from said outlet tuyeres, a blower for forcing air through said tuyeres and fuel bed, means for agitating the fuel in said hopper to prevent arching therein, and a motor for driving said fuel feeding means, said blower and said agitating means, all of said elements constituting a self-contained unit adapted to be mounted exteriorly of 'a boiler and be detachably connected thereto.

27. A combined automatic stoker and ,furnacei comprising a fuel hopper, an elongated, station-;

ary combustion chamber extending at an angle to said hopper, means intermediate said hopper and combustion chamber for feeding fuel from said hopper to said combustion chamber and for positively moving the body of fuel therethrough, said feeding means and combustion chamber. being so constructed and arranged as to continually provide a burning zone of predetermined thickness, means for providing a cross-draft of air to one side of said combustion chamber substantially I transverse to the direction of movement of the fuel body therethrough and to support combustion therein, and means for conducting the gaseous products of combustion from the opposite, side of said combustion chamber..

' .28. In an automatic stoker, afuel hopper, a combustion chamber laterally disposed with respect to said hopper, the walls of said chamber I providing a burning zone of definite cross sectional area and volume, means for feeding fuelfrom said hopper to said combustion chamber and for positively moving said fuel therethrough, the

body of fuel thus supplied completely filling said combustion chamber and thereby constantly providing a fuel bed of predetermined thickness, and tuyeres in the opposite walls of said combustion chamber for supplying air thereto and withdrawing the gaseous productsof combustion therefrom in a. direction} substantially transverse to the direction of movement of said body of fuel there- 29. In' an "automatic stoker, a fuel'supply, a

' combustion chamber the walls of which provide a burning zone of definite cross sectional area and volume, means for positively feedingjfuel from said supply into said combustion; chamber to maintain said chamber completely-filled with fuel A and for moving said fuel through said chamber, whereby a burning fuel bed of predetermined thicknessis provided, and inlet and outlet tuyeres in opposite walls of saidchamber for providing a draft which is'throughout substantially at right angles to the direction of movement of said fuel theretfirough.

'wns'ronu. FULTON-v.1

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