US2546171A - Stoking apparatus ash removal means - Google Patents

Description

March 27, 1951 c. E. SHAFFER ET AL 2,546,171

STOKING APPARATUS ASH REMOVAL MEANS 3 Sheets-Sheet 1 Original Filed March 15, 1940 0 v RE. n M M w s 0 jam 5/ R E0 r w y w. cak m March 27, 1951 c. E. SHAFFER 'ET AL 2,545,171

STOKING APPARATUS ASH REMOVAL MEANS 3 Sheets-Sheet 2 Original Filed March 15, 1940 am HuQEu:

n 12 aunt: no 632 l l u 1 l 1 1 l l -J INVENIORJ & CHESTER E SHflFFER,

H70 FISHER,r/Q.

ATTORNEY.

March 27, 1951 c. E. SHAFFER ET AL 2,546,171

STOKING APPARATUS ASH REMOVAL MEANS s Sheets-Sheet 5 Original Filed March 15, 1940 r 5 WW8 N r e #5 0 mi 7 4 mm 30 #2 4 Y B Patented Mar. 27, 1951 STOKING APPARATUS ASH REMOVAL MEANS Chester E. Shafier, Arlington, N. J., and Albert Boyd Fisher, J12, Wilkinsburg, Pa., assignors to Koppers Company, Inc., Pittsburgh, Pa., a corporation of Delaware Original application March 15, 1940, Serial No. 324,048. Divided and this application August 1, 1945, Serial No. 608,232

4 Claims.

The present invention relates to the domesticheating art. More particularly, the present invention relates to the ash-removal means disclosed in our Patent No. 2,388,294 granted November 6, 1945 of which this application is a division.

The domestic heating furnace described in Patent 2,388,294 comprises apparatus for automatically withdrawing solid fuel from a nearby storage bin by a conveyor, delivering the fuel to an underfed stoker tube through which the fuel is forced into a fuel bed supported upon an oscillatory grate. The oscillating movement of the grate acts to work ash and clinker through the fuel bed to the grate and to break up and force the ash through the grate into a furnace hearth under the grate. From the hearth the ash is positively moved into an ash-pit.

In the coke stoker illustrated in Patent 2,388,294 fuel is burned in the bed continuously and a single motor is used for operating all movable parts used in feeding the coke and disposing of the ash. The fuel feeding mechanism and the ash-removing mechanism are not operated continuously, but are put into operation to feed fuel to the fire bed and remove ash from the fire bed and furnace hearth when the consumption of fuel in the fuel bed has lowered the surface of the bed below a predetermined level. When the fuel feeding operation tends to increase the surface level of the fuel bed above a predetermined point .the operation of the mechanism is discontinued.

The primary object of the present invention is to provide an apparatus for moving the ash from .the furnace hearth to an ash disposal pit which is simple and dependable in operation.

Another object of the invention is to provide an apparatus for moving ash from the furnace hearth to a disposal pit which is quiet in operation and effective irrespective of the type of ash to be disposed of.

The invention has for further objects such other improvements and such other operative advantages or results as may be found to obtain in the apparatus hereinafter described and claimed.

In the accompanying drawings forming a part of this specification and showing for purposes of exemplification a preferred apparatus in which the invention may be embodied and practised but without limiting the claimed invention specifical- 131 to such illustrative instance or instances;

l is a partial plan view with parts broken away, of the furnace-grate, the stoker, the conveyor means for feeding fuel from storage to the grate, the ash-bars, and the actuating means for operating the fuel feeding and ash removing apparatus. v

Fig. 2 is a side elevational view with parts shown in section taken on the line IVIV of Fig. 1 and showing the adapter-member whereby fuel moved from the storage bin by the conveyor is introduced into the underfeed stoker, the figure also showing in full lines one of the ash-bars 9| of the present invention, and their operating connections, and also showing their orientation relative to the ash disposal pit;

Fig. 3 is a vertical sectional view taken along the line VV of Fig. 1;

Fig. 4 is a plan view of the feed-tube of the stoker member with parts broken away to show details of its interior construction and the improved ash-bars of the invention, and the ash-pit.

Fig. 5 shows in diagram electrical circuits employable in actuating the instant system for feeding solid fuels to domestic furnaces according to the present improvement.

Figure 6 is an isometric diagrammatic view of the ash removal apparatus with other apparatus of the stoker broken away showing the driving mechanism.

As the present invention is of general application, for example, it may be used with various other types of stoking apparatus, as well as being of especial utility with the tyne of apparatus of our aforesaid Patent No. 2,388,294, which is hereby expressly made a part hereof by crossreference thereto, a brief description herein of only so much of the general features thereof as is essential to an understanding of the present invention will suffice for an understanding of the same,

The same reference characters used in said Patent No. 2,388,294 will be used herein to designate the same parts in each of the several views.

The conveyor means for transporting fuel in a horizontal plane between the bin and the stoker members of the unitary system comprises plate 3| that is reciprocally mounted in a sheet metal housing 32, Figs. 1 and 2. It is slidably supported above the bottom of its housing 32 on metal strips that serve as tracks. The said conveyor-housing 32 extends from a. coke-bin to the stoker inlet. Metal-covered wooden strips 34 are affixed to the walls of conveyor-housing 32 and the wooden stri s 34 form a sort of recess in which the reciprocating conveyor-plate 3| is actuated, and'have the effect of directing all fuel that flows into the bin-trough only onto said plates upper surface.

Beneath the reciprocatory plate 3| of the conveyor and afiixed thereto at its outer end is connecting-rod 36, Fig. '1 whereby it is actuated by the electric motor that is adapted to operate the unitary system, said connecting-rod being attached to the conveyor-plate 3i by means for increasng or decreasingthe amount of movement imparted to the conveyor-plate during 'each.

stroke of the connecting-rod and, consequently, to regulate the quantity of fuel carried from the bin during each cycle of movement of the conveyor-plate.

The conveyor housing is provided, for purposes of cleanliness, with cover-platez39.

Adjacent the discharge orlinner end of 'conveyor 3B, the reciprocatory plate.3l and the recess-forming members 34 therefor are both supported on the horizontal surface .of the inlet to adapter-member 4!, Figs. 1 and 2,.ithati-is :held atop the sto"er apparatus, and which serves to direct conveyed fuel downwardly onto the actual stoking device of saidstoker. Cleats 4i) allow free movement of the conveyor-plate 3 I.

Flexible finger [4! attached to the walls of adapter-member 'eL'as shown in Fig. 1, can be moved by its associated thumb-"sorew'to restrict orincrease the free-way for fuel flowing along the conveyor-plate 3i and serves as means for "obtaining fine regulat on of the quantity of fuel delivered from storage to the Stoker during any period.

Adapter-member ii, for directing conveyed "fuel-into the stoker'apparatus, is supported in the circular inlet to the stoker tube by means of screwslsas-shown in Fig. 2; in consequence of this arrangement, the adapter and its associated conveyor are pivotable around the stokerinletand can be thus arranged at a diversity of angles to the stoker and the furnace.

As also shown in Fig. 2, a damper valve 44 is installed at the inlet side of said adapter-member M to close the air passage between the conveyor and the slicker-during such times as fuel is'not being introduced into the latter,thereby to prevent combust on-air being drawn into the furnace through adapter 4| and stoker tube52 when they are only partially filled with solid *fuel at :any interval. As shown in Fig. 2, dampervalve 44 is supported at its 'top by'a'hinged arrangement 'to the-walls of adapter 4| adjacent its'inlet. Finger-45 depending from one end of the hinge-pin serves to open and close said damper-v-alve, said fin er being automatically actuated by arm 46,'that is attached to and moves correspondingly with connecting-rod '36 in such manner that during the Tor-ward stroke of the connecting rod, when coke is being delivered to .the stoker, thedamper'is'open'e'd and conversely 'is closed on the return strokeofsaid connectingrod. Asconnecting-rod 36 is always attheend 4 of its back stroke when the unitary system is at .rest, damper-valve a: is opened position only ering 83 for the working parts of the assembly.

Referring now -to'Figs. 1' and '2, the stoker apparatus with which is incorporated the present invention is of the underfeed type and comprises a casting 52 having a relatively extended, horizontal section that, beneath the furnace-grate,

terminates in'substantially a right-angle bend on the upper surface-of which there is supported a removable extension-ring 63, the vertical section I of the 'stoker-tube and said -'-extension-ring sweep.

being flared slightly outwards, thereby to facilitate flow of fuel through the tube @and impede backward movement ofsuch thereofas has been elevated above its horizontal section.

Casting 52 is essentially a hollow, cylinder-like body whose top and side walls are of continuous metal construction. In the bottom of the casting, there is a large rectangularly-shaped opening thatextends from directly beneath its fuel inlet upto :apoint', somewhat short of its upward Themerober 52 is lined with replaceable liner-*platesBB that cover most of the lower part of .the side .walls of the tube and are conveniently formed of cast iron, hard-surfaced steel, or other: appropriate material.

These plates 53 are of greater thickness adjacent the fuel inlet of thestoker-tube than they are further therealong, as shown in Fig. 4, their vertical edges thus formin a sequence-of ridges or oifsets that have the-effect of presenting to the solid fuel as it traverses the casting inthe direction of the grate, tube-sections of increasing cross-sectional area which facilitate thestoking operation and tend to restrict any backward movement of the stoked 'fuel during the backward stroke of the reciprocatory Stoker-plate 5|.

'Recipro-cally mounted within the tube-casting E2, and forming a substantial portion of its lower wall, is the:stokerplate 5| which, adjacent theirilet-en'd of said tube-casting, is mounted on-cr-oss head ll of thedriving mechanism for the unitary system and extends through a providedslit in the adjacent end-wall of said 'casting. At its opposite end, said Stoker-plate is rigidly afiixed to the upper surface of ram-head 59, the said cross-head, plate, and ram-head being all arranged for reciprocatory movement as aunit. The shelf-like ridges 62, shown in Fig. 3, :on the inner walls of thetube-casting form a track for the Stoker-plate during its recipro- "ca'tory movements.

tube casting have threaded holes containing bolts 5Swhose heads serve as feet for said casting and whereby the stoker can be levelled.

That lower wall-portion of the Stoker-tube, adjacent the point where the stoked fuel undergoes a sharp change of direction, is naturally subjected to heavy abrasive action by the fuel. It has therefore been found expedient, for lengthening the operative life of a stoker-tube, to form its walls in this part of extra thickness of metal, as shown in Fig. 2; in the same figure, there is also clearly illustrated rib I33 that is cast integrally with the stoker-tube walls and which, in

combination with the hereinabove described finger-bar 6i and also the adjacent offsets formed at the termini of liner-plates 53, assists in supporting, above the normally only partially filled horizontal section of the Stoker-tube, that vertical column of fuel which is about to be elevated into the fuel-bed by the movements of the reciprocatory ram-head 59.

The upper edge of extension-ring 63 is flanged and presents a smooth surface whereon there is rotatably supported, by means of a co-acting groove, the grate 6B of the unitary system. For simplicity of fabrication, the grate can be formed of sections having integrally-cast lugs whereby said sections can be bolted together to form a single rotatable unit. The smooth upper surface of said grate lies in substantially a horizontal plane and its slotted perforations 98, that extend through the body thereof for the removal of ashes from and for the admission of combustion air to the fuel bed, are arranged in groups according to a barred pattern wherein each has at least one slot substantially radially disposed whereas the remainder are in parallelism therewith.

Difectly beneath the grate for which it can function as means to prevent tipping of the former in the event of unequal loading, or the like,

but operatively independent thereof, is the ashring which is supported by radial brackets that are themselves supported at their inner ends on the outer walls of extension-ring 63. Ash-ring 80 is formed of arc-like sections bolted together, the ends of such sections having slot-like openings that permit adjustment of its overall diameter, so that its periphery can be made substantially equal to that of the grate or be increased somewhat thereover. This feature of extensibility of said ash-ring is of special importance in K that it permits the employment of a grate of some standardized dimension in an existing furnace having a fire-box of which the internal diameter is so much greater than that of the grate that otherwise excessive leakage of ash and of fuel would take place in the peripheral space therebetween. The closing of this peripheral space by the ash-ring is susceptible of further refinement by supporting thereon, during the installation of the apparatus, a seal 84 formed from an asbestos cement, or the like.

In accordance with the present invention, after ashy combustion residues have passed through the slots 98 of the grate, they are removed from the floor or hearth of the furnace under the grate and carried therefrom to an ash pit or receptacle by means of the hereinafter described ashremoval apparatus.

Referring particularly to Fig. 6 in which the ash removal apparatus is shown isometrically and separated from other components of the unitary system, the motor H2, gear reducer H3, crank arm I I4 and lever I I5 provide the reciprocating driving force to the ash removal apparatus. Interconnected for simultaneous reciprocal movement from the lever H5 is the cross-head 1|, member I34 and stoker plate 5| to the underside of which is attached the vertically disposed connecting bar or post 99. A cross-head es depends from the said post 99. A pair of reciprocatory slide bars 9| as shown in Figs. 1, 2, 3, i, and 6 are pivotally secured to the cross-head 9G with which they move backwards and forwards in unison. Adjacent their opposite ends, the bars 9| are slidably held in guides 93 therefor which are spaced apart a distance greater than that cbtainingbetween the said bars pivots on their cross-head. During their reciprocatory movement the ash-removal bars are thus provided with some lateral as well as lengthwise movement, the former said movement serving to clear the path through the accumulation of'ashes that are retained in a pile on the floor of the furnace within the restrictive area defined by the furnace walls. The said path so-cleared by the lateral movement of the slide-bars 9| is wider than the bars, so that any of the ashes falling upon their upper surfaces can be moved along such surfaces and out from the furnace-hearth without being brushed off by adjacent material of the ash-pile.

As shown particularly in Figs. 3 and 6, longitudinal guide plates I55 having integral cover plate I55A are mounted at each side of the stoker tube 52 and extend along the sides of the slide bars 9! from the hearth to the ash receptacle or ash-pit 95. The ash which is moved from the furnace hearth toward the ash-pit moves between the guide plates I55, and the side walls of the said guide plates support ash lying at approximately its angle of repose from the sides of the guide plates down to a trough extending longitudinally along the slide bars 9 I. The guide plates I55 confine the ash within a channel extending from the hearth to the ash-pit and assist the bars 9| in directing the ash from the said hearth to the ashpit essentially by retaining the ash along the sides of the slide bars 9! in much the same manner as the furnace wall retains the ash in a pile on the hearth. Ashes extracted from the furnace hearth, by the movement of the ash-removal bars, drop from their surfaces into ash-pit 95 and into a therefrom removable container, if pre ferred.

The integral cover plate |55A prevents the flow of excess air into the furnace hearth through the opening required for ash removal. Cooperating to prevent uncontrolled inflow of air through furnace-hearth openings to the grate is a tightly fitted'metal plate 92 which fills the space customarily covered by an ash-pit door and fits closely around the stoker tube and ashremoval apparatus. Fitted against the plate 92 as it extends from the face of the furnace and smoothly joining the same to the furnace walls is a further section of the overall sheet metal stoker-cover 83.

In its embodiment shown in the drawings, the present unitary system is arranged for actuation in response to fuel requirements of the fuel-bed to keep the same at a constant level. Means for accordingly actuating the unitary system coinprises geniculate rod I ill to which is affixed at its lower end a truncated metal body I I12, preferably formed from such resistant alloy as Ni-Resist, or the like, that is in constant contact with the upper surface of the fuel-bed, said rod being pivotally mounted on a bracket for movement in a vertical plane, so that the member I 22 can easily follow small changes in the level of the upper surface of the fuel-bed. Counterweight I I3 is adjustably mounted on the outer end of rod It! thereby increasing its ease of movement and sensitivity to changes in the fuel-bed level and also functioning to prevent the said rods own weight causing its sinking below the surface of the bed. Adiustably affixed to the said geniculate rod where it extends through switch-box HM, there is an electrical switch, pr ferably of the Mercoid type, that is included in the circuit driving electrical motor I I2 whereby the unitary system is actuated. The said switch is disposable to open or close said circuit when the u per surface of the fuel-bed has respectively been for any reason raised or lowered beyond a predetermined level. The opening of said electrical switch however does not necessarily stop motor H2 immediately, unless the driving rod H5 for the assembly is at the end of a full backward stroke, as will be hereinafter set forth.

The above-describedfeatures of the system'are all interconnected for simultaneous movement by means of electrical motor H2 operative through speed-reducer H3, crank-arm H4, and the single driving-rod or lever. I I5, all of said members being mounted on the'basal casting Ill. 'Pivotally attached to lever I I and adapted to be reciprocally moved thereby is cross-head?! to which is bolted the one end of stoker-plate 5| that reciprocates inside of Stoker-tube 52.

All of the driven parts of the apparatus, that is, conveyor member 3 I, stoker-plate 5|, ash-bars f1! and grate 60, are arranged to communicate directly or indirectly with the said driven crosshead ll. Viewing Fig. 1 from that end thereof adjacent the actuating motorythere is observed at the right-hand side of the cross=head H a thereto afiixed arm containing an extended obtuse-angled slot H6 which terminates at its upper end in a short transverse slot. By means of the illustrated belt that -can be slid along said slot HS and secured at any preferred position therein, link I I? is pivot-ally secured to said cross-head and serves as a connecting arm whereby reciprccatory motion of the cross-head is utilized to reciprocate the two cranks H8, disposed at right angles to each other, about their own pivot, which is supported in the bracket E 2i attached to the lower side of the adapter-mem her =31. ent drawings, as well as those of the aforesaid. parent application, were made, the two cranks l id, shown at right angles to each other in Fig. l, were, as indicated therein, adjustable to any angle, about their own pivot, so that when the angle of approach of-the conveyor to the stoker is changed, the angle between the crank arms H8 may be changed. Through thisleversystem, reciprocatory movement of the cross-head is resolved into similar movement of connectingrod which actuates the fuel conveyor-plate 3 l. The particular shape of obtuse-angled slot H6 and the adjustable angle between cranks H8 makes it possible to dispose conveyor-plate 3i at a wide range of angles-of-apprcach to the stoker inlet and yet to employ the motion of member H for operating the conveyor-plate to feed the stoker.

Operatively connected with the opposite end of cross-head H is the train of co-operative devices whereby the furnace-grate is, accordingly, made adjustably rotatable about its vertical axis, as there is required a greater or lesser removal of ashy residues, and the like, from'the fuel-bed during any period of combustion. Within linear slot 72 of the cross-head, the effective length of said slot, as is clearly visible in Fig. 3, being simply regulable by means of a screw bolt E3 that is adapted for movement longitudinally thereof, the pin 19 is adapted "to slide freely independently of the cross-head a distance determined by and regulable according to the accorded space between the end of said bolt 13 and its 'ad jacent slot-end and the said end of the bolt and said slot-end are adapted to engage said pin at some point during respectively the backward or forward movement of the reciprocatory cross-- head, and in so doing, to move in the same dire-3 tion the link M which is pivotally moveable at bothits ends. Movement of said link '54 by pressure of the cross-head thereagainst effects cor responding movement of link 18 that is supported on a bracket, projecting from walls of the underfeed-tube, by the bolt I09 which also serves to support for movement independentlyof saidlink In the apparatus'from which the pres- 8 1B the ratchet 61 which is rotatable around said bolt.

:Spring. actuated click 68 and pawl 59, of which the former is mounted on a pin for independent movement on lever '10 whereas the latter is similarly mounted on the above-mentioned bracket affixed to the walls of the stoker-tube, are so disposed in respect of the teeth of the ratchet 61 that pawl 69 engages a tooth thereof during the forward stroke of the cross-head thereby allowing lever 18 similarly to move about pin H30 independently of the ratchet and the click 68 to advance in the direction of pawl 69 a number of teeth that is regulable by the effective length of slot #2, and during the backward stroke of the cross-head, click 68 under the influence of its actuating spring is arranged to engage the adjacent ratchet-tooth so that both ratchet and the lever?!) are simultaneously moved in a counter clockwise direction. During backward movement of the cross-head, pawl 69 slides over the moving ratchetteeth.

By means of the above-described train of apparatus, the reciprocatory movement of crosshead ll -is translated into an intermittent moving of the ratchet always in a counter clockwise direction. During its rotation around pin I00, the ratchet carries with it link 75 mounted there on b pin l3 and about which said link is rotatable. At its opposite end, the link 75 is rotatably attached to one end of the centrally-pivoted lever 65 on either end of which an adjustable lever-rod i5 is pivotally mounted, the opposite ends of saidrods 36 being also pivotally mounted on shoulders H that are cast integrally with grate .on its lower surface where they are disposed along a diameter and whereby said grate is provided alternately with a clockwise and counter clockwise movement in a horizontal plane.

Rotation of ratchet 61 moves link 15 in alternation forward and backward thus respectively pushing and pulling that portion of member to which it is attached and thereby causing said member to oscillate on its pivotal mounting and move the grate member alternately in opposite directions in a horizontal plane.

The total movement of the grate in any one direction is accomplished in sequences of stepwise movements whose lengths are variously adjustable, thereby enabling the householder to increase or diminish the amount of agitation, incidentally imparted to the fuel-bed, in accordance with the combustion results he wishes to effect with an individual fuel. This feature of adjustability of grate-movement is of important advantage for promoting the automatic delivery of heat over protracted periods because it permits either a regulable removal of combustionresidues from the grate and, in consequence, the maintenance of a constant rate of consumption of combustible notwithstanding changes in the ash content of the employed fuels, or, in the case of any particular fuel, a removal of ash from the fuel-bed that can be either increased or decreased to respectively enhance or diminish accessibility of combustion air to the burning fuel and correspondingly alter the rate of consumption of its combustibles. This is all simply and easily effected by suitable adjustment of screw-bolt l3 toregulate the eifective length of slot 52 of crosshead H, which in turn controls the number of teeth of the ratchet over which click 63 passes before becoming engaged for the'backward stroke of the cross-head.

As hereinbefore mentioned, perforate slots 98 of grate 60 are arranged in a particular barred pattern wherein the slots are disposed substantially on or parallel with a diameter of the grate and. the remainder in substantial parallelism with them. During the grates rotational movements about the axis of its supporting extensionring 63, successive contacts of the wall-edges of slots 98 with the fuel or ash particles lying adjacently thereabove tends, in consequence of their changing angle of incidence in respect of surface irregularities of such materials, to provide said particles with rotational movement around their own axes in addition to that motion which is contributed by the grate itself. Such rotational movement is of course most pronounced near the grate periphery where the ash content of the fuel-bed tends to be the highest and therefore the greatest agitation of the fuelbed is needed to remove the ash sufiiciently rapidly therefrom to prevent its fusion into large size clinkers. To the lower surface of any such clinker as does form on top of the grate, the said changing angle of incidence with which a succession of slots comes into contact therewith tends, assisted by the weight of the fuel-bed thereabove, to shear the clinker into fragments capable of passing through the grate-slots and being discharged from the installation by means of ashbars 9 I. The facility with which the apparatus is operative to maintain a clean fuel-bed, i. e. one that is relatively free of ashy residues and clinker, and from which such residues are continuously and automatically removable for extended periods, is, it is felt, in large part the result of this particular configuration of the grate-slots and the resultant special movement contributed by it to the fuel-bed, in combination with the regulability of the length of the steps with which the grate is moved between its limits of travel.

Mounted on basal casting III of the stoker apparatus is switch box I3I that contains a Mercoid switch which is itself supported on rotatable finger I32, said finger being under the influence of a spring member that always returns it, when moved therefrom, to a pre-arranged position and carries with it the Mercoid switch which, in

' the pro-arranged position of the finger, is supported in such manner as to close the electrical circuit. Finger I32 is also so disposed that, during each backward stroke of cross-head H, the outer end of that extension therefrom containing slot IIG moves said finger about its supporting shaft in the same direction, thereby tipping the attached Mercoid switch into a position to break flow of current therethrough. On the forward stroke of said cross-head, finger I32 and its associated switch are returned to the reverse position by the spring attached thereto. Connected in parallel with the Mercoid switch in box I3I is a similar switch that is contained in switch-box I04 and is arranged for movement, by the upward and downward movement of fuel-bed-level control IIJI, between positions adapted to open and close the electrical circuit to motor II2 respectively as the fuel-bed is stoked to reach a pre- 10 til driving-rod H5 is at the end of its backward stroke when both switches and the motor-circuit will be in open position until member I02 again sinks with the fuel-bed level and moves the therewith communicating switch of I65 to close the circuit to the motor.

This feature whereby driving-rod I I5 can come to rest only at the end of its backward stroke assures, upon its restarting, that motor H2 is always under the least possible load, thereby, at that instant, insuring against heavy current flow and damage to the motor of which the size required depends upon its starting-load.

Members I5I, I53 and I54 of Fig. 5 represent respectively circuit fuses, the lines that serve as a source of power, and a power-line switch.

The working parts of the assembly are all encased in a sheet-metal covering 83 to enhance its appearance and protect its working parts. Above adapter-member 4|, a portion of said covering is formed as a removable cover-plate that provides ease of access to the several mechanical features.

The ash-bars 9 I, that are attached to the lower part of reciprocatory stoker-plate 5| are correspondingly reciprocated with the latter, all said members being actuated from cross-head II and in such manner that those employed for conveying materials all move simultaneously in a forward or return stroke.

By the reciprocatory motion of the ram-head as, new quantities of the employed fuel are elevated into the vertically-extending section of the stoker-tube and displace that already there into the fuel-bed atop grate 69, the inflow of such fuel giving more especially the center of the fuel-bed a measure of agitation and causing a sort of radial flow outward of the fuel particles already therein.

At the same time that the conveyor-plate 3| and Stoker-plate 51 are performing their operations, the grate is being moved either clockwise or counter clockwise in steps of regulable distance along an arc of the circle defining the outline of the grate, thereby revolving and rotating between themselves those particles of unburned fuel and ash closer to the periphery of the grate, such movements causing the fine particles of ashy residues to fall through the interstices of the fuelbed and the grate-slots 98 onto the furnacehearth therebelow where they are picked up on the upper surfaces of the simultaneously reciprocating ash-bars 9i and moved out of the hearth space toward the front of the furnace whence they fall into ash-pit 95. When sufiicient new fuel has been introduced into the fuel-bed to raise member IE2 to apredeterminedlevel, the Mercoid switch, in switch-box I04, will be moved to stop current flow therethrough whereupon, during the subsequent backward stroke of driving-rod I I5, contact in the Mercoid switch of switch-box I3I will be broken and the system come to rest until the next demand for fuel by the level control.

in such unitary system for employing solid fuels, it is however insufficient merely to furnish co-operative features of apparatus that are adapted to perform the above-stated operations, because the more common of such fuels vary from one to the other in certain of their characteristics; notably, their ash contents. It is, therefore, highly desirable for the assurance of continued automatic operation over a protracted period, that the component apparatus of such a system be not only co-operatively disposed but also that their individual operations be so regu lably co-ordinable within the system that operative results of the one can be made consonant with that of another. For example, with fuel of a given ash content being consumed on the grate at an established rate and with a corresponding delivery thereof to the fuel-bed by the conveyor and stoker, an established angular movement of the individual steps of the grate in its rotary mottion can provide just that amount of agitation to the fuel-bed necessary to give removal of ashes therefrom and from the grate that is adequate to keep apace with their formation, thereby assuring good conditions of combustion and nonformation of clinker that might otherwise accumulate on the grate to prevent combustion air reaching the fuel and thus extinguishing the fire. With such co-ordination of these apparatus of the system, excellent combustion conditions can thus be automatically maintained for an indefinite period; Let it now be assumed, however, that the source of solid fuel is changed to one having a higher content of ash but that it is still desirable to burn the combustible of the new fuel at the same rate as in the previous instance. This means that to deliver the same amount of combustible to the grate for a given period, a larger quantity of fuel will necessarily have to be conveyed to the stoker. In the system this is simply done by increasing the amplitude of movement of conveyor-plate 3! or by retracting finger Mi closer to the walls of the conveyor shell. In consequence of the fact that more ash will accumulate in the fuel-bed with fuel from this new source, it will become necessary, for the obviation of undue accumulations of such material in the fuel-bed, to increase the amount of agitation ascribed thereto by the grate in its stepwise movement. This circumstance is simply provided for by so moving threaded bolt 1'3 as to decrease the effective length of slot '52, that determines the extent of each angular movement of the ratchet, and which in turn will increase the angularity of each movement of the grate and the resultant agitation of the fuel-bed, thereby increasing the rate. of ash withdrawal through the grate onto the hearth. With more rapid accumulation of ashes on the furnace-hearth ashes will be automatically piled higher on the top of the ash-bars ill and during each cycle of their reciprocatory movement more ash will be carried to the ash-pit.

If, on the other hand, it is desired to employ more freely-burning solid fuel of sharply reduced ash content which makes it desirable to decrease the rate of ash withdrawal and even to allow a layer thereof to accumulate on the grate in order to reduce the natural draft, the stepwise movement of the grate can be reduced to establish such condition without altering an established setting of the conveyor 3|; or, as is now obvious, with any given solid fuel, the extent of movement of the conveyor-plate 3! can be adjusted to meet the demands of the fuel-bed for any rate of its consumption, and the agitation thereof be arranged properly to remove the ash for such rate by co-ordinative adjustment of the grate movement to that of the conveyor-plate.

By means of the present improvements in stoker systems it is now possible to assure, for domestic-heating installations, apparatus whereby, for any solid fuel, an appropriate and precise adjustment is always establishable between the rate of fuel delivery, its rate of combustion, and the rate of ash withdrawal from the heating system, so that these factors are always in equi- 12 librium to give optimum combustion conditions for any of the common solid fuels.

Ihe invention as hereinabove set forth is embodied in particular form and manner and may be variously embodied within the scope of the claims hereinafter made.

We claim:

1. The combination with a hearth under the grate of a heating furnace of an ash receptacle positioned adjacent the hearth and means for delivering ash from the hearth to said receptacle comprising: a driving member, a pair of longitudinally arranged bars mounted closely adjacent the hearth surface and arranged at an acute angle to one another with one end of each bar movably connected with the driving member, the other ends of the bars being slidably mounted and more widely separated than the driven ends, and means to reciprocate the driving member to move the bars longitudinally, the mounting of the bars being arranged to give both lateral and longitudinal movement to the bars during the reciprocating movement.

2. The combination defined in claim 1 in which the bars are flat and are mounted substantially parallel with the hearth surface.

3. In combination with a hearth under the grate of a furnace of an ash receptacle positioned adjacent the hearth and means for delivering ash from the hearth to the receptacle, said means comprising a driving member positioned over the receptacle, a motor having a crank connection for reciprocating the driving member, a pair of divergently arranged flat bars pivotally connected to the driving member, guides disposed under the grate and mounted to slidably support the bars at their divergent ends and guides mounted along the sides of the bars between the hearth and the ash receptacle to confine the movement of the ash from the hearth to the ash receptacle.

4. In combination with a hearth under a grate of a heating furnace, an ash receptacle positioned adjacent the hearth and means for moving ash residue from the hearth to the receptacle, said means comprising: a fiat bar mounted for movement closely adjacent the hearth to move within ash upon the hearth, said bar having a plane, smooth upper surface, an actuating lever pivotally connected with one end of the bar, a guide for supporting the other end of the bar, means to impart a reciprocating movement to the actuating lever, the mounting of the bar being at an acute angle with reference to the line of reciprocation of the lever whereby the reciprocating movement will 'move the bar both longitudinally and laterally in advancing ash to the receptacle.

CHESTER E. SHAFFER. ALBERT BOYD FISHER, JR.

REFERENCES CITED The following references are of record in the file of this patent:

Ulx'l'iED STATES PATENTS Number Name Date 676,930 Wees et a1 June 25, 1901 896,410 Poppenhusen Aug. 18, 1908 968,844 Girtanner Aug. 30, 1910 1,116,062 Heer Nov. 3, 1914 1,837,994 Preston Dec. 22, 1931 2,022,716 Grine et al. Dec. 3, 1935 2,118,651 Macchi May 24, 1938 FOREIGN PATENTS- Number Country Date 344,157 Germany Nov. 18, 1921

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