Патент USA US2116774код для вставки
May 1_0, 1938. 2,116,774 J.> H. WALTER MECHANICAL ST‘OKER Filed Nov. 25, 1932 5 Sheets-Sheet 1 mRNan! n bw QNum“ ., . m. Tm ` m, , |l. \\ Nî Èmkì Qo.3è \\\m»QNNQwwN\.w NQQN `„ „QN È h. o`|„wwwW, @«wm»MmäQW»/uN@ www mwN mmmm@ www@ wmwÑv , omQQNœ@“Ö ¿VIL „LaomN@/QwN.mwmv, NÚ.ä„n\b . mi*wQQàwMQ@ y Inval/#rsf @fosa/äh H May 10, 1938, ` J. H. WALTER ' ` 2,1169774 MECHANICAL sToKER A Filed Nov.. 2S, less 5 sheets-.sheet 2 May 10, 1938>.' 2,1 176,774 J. H. WALTER ME‘òHANIcAL sToKER Filed N'ov. 25, i932 È Sheets-»Sheet 3 9.9 100» @fase/ah H @ad , f/ Mavim, 1938. ` I J. H. WALTER MECHANICAL sToKER Filed Nov. 25; 1952 \\\\\\\\\\\\\\\\\\\\\\\\\\\’A/// ///// PLILL r i 2,116,774 | 60 5 ` . _ '5 Sheets-Sheet 4 »_ May 10,1938. J. H. WALTER 2,116,774 MECHANICAL STOKER FiledNov. 25, 110,32 Il: a. 5 Sheets~$heet 5 Pnienied Mey 1o, 193s » 2,116,174 ' UNITED s'i‘iiTEsA PATENTl oEFiCE MECHANICAL _STOKEE Joseph Henry Walter, Springfield, Ohio, assignor, by mesne assignments to The Steel Products Engineering Company, Springfield, Ohio, a cor poration of Ohio Application November 25, 1932, Serial No. 644,247 -1Claim. The present invention relates to improvements in mechanical stokers.v ' ' . 021e of the important objects of the invention ` is to provide a new and improved mechanical 5 s_toker of the underfeedtype having a burner re tort in which air under pressure is supplied in such a manner that the‘unburned fuel in the bed is evenly distributed. l ‘ ` closed, but intend to cover all modiñcations and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims'. e Referring more `particularly to the drawings, 5 the specific stoker selected for illustration of the invention is of the underfeed type, and comprises in general a burner retort I0 opening upwardly and adapted to be suitably located in a combus tion chamber (not shown), a vertical hopper Il 10 . a burner retort with air and’fïelìîipply-«ducts~mmounted externally of the combustion chamber oœning to one side and with air inlet openings and adapted Vto be supplied with the fuel to be relatively small in size and in aggregate area in burned, a fuel passage preferably in. the form of a cylindrical duct I2 connecting the base of the the side located adjacent the ducts and relative i5 ly large in size and°in _aggregate area in the side hopper to the underside of the retort, and power- 15 . «WA more specific object is to provide a novel m mechanical'stokerm?theeunderfeed type having located remotely of the ducts', whereby increased driven fuel feeding means, preferably in the form of a rotary screw conveyor I3, for advanc~ ' combustion tends to occur in the region of the last mentioned openings to compensate for any ing the fuel from the hopper through the duct v into the retort as required. Air of combustion excess distribution of fuel otherwise tendingo to under pressure is adapted to be supplied to the retort through a conduit Il from any suitable Further’ objects and advantages vwill become source,i0 such for example las a power-driven apparent as the description proceeds. centrifugal blower I5. Ashes and other residual In the accompanying drawings, Figure 1 is a plan view of a stoker embodying matter of combustion from the retort- I0 are _ adapted to. be removed automatically as quickly 25 features of the invention. 2 theFig. 2 is a longitudinal vertical sectional view as produced by means of a power-_driven ash re mover, preferably in the form of a rotary screw taken substantially along line` 2-2 of Fig. 1. Fig. 3'is a longitudinal> vertical sectional view conveyor I6 operating in a conveyor duct I1. While in some aspects of the invention the ` taken substantially along line 3-3 of Fig. 1. 30 Fig. 4 is a perspective view of a shear plate burner retort i0 (see Figs. 9 to 12) may be pro- 30 vided in any desired form.` preferably it is gener ' forming a closure for the hopper base. . Fig. 5 is a .horizontal sectional view of the ally circular in shape, and adapted to be mount in a combustion chamber of- similar shape , transmissionin the stoker drive taken along line ed (not shown in detail, but represented diagram 5-5 of» Fig. 2. ‘ in Fig. 3 by thewall 18). -35 Fig. 6 isle ien end eieveiicnni view of the matically riphery of the retort i 0 is separated from the wall stoker. Fig. '7 is a fragmentary horizontal sectional view I8 to provide an annular space i9 which consti tutes a pit adapted to receive ashes and any other looking upwardly along line '|--1- of Fig. 9. Fig. 8 is a fragmentary'detail sectional-view residual products of combustion overflowing from 20 occur. ` , . 40 taken substantially along line Hof Fig. 2l. Fig. 9 is al vertical sectional view ofthe burner retort taken along line 9-9 of Fig. 1. Fig. 10 is a fragmentary plan view of the „retort partiallybroken `away and sectioned along line the t'op. ' In its preferred form, the retort I0 comprises a hollow generally cylindrical base wall 20 closedv Vat the bottom by a cover plate 2l. An upwardly opening fuel chamber 22 vis Iocated‘within the wall 20, and has a circular o_utlet coaxial with 45 and inv the same plane as- the >upper edge of` the wall. The fuel chamber 22 converges in size ' line il-ii of Iilg. 10. and curves downwardly and laterally and is inte ` Fig.' 12 is ‘n transverse vertical sectional view. gral with the inner end of a horizontal sleeve' 23 5c wniie ine invention is eiacepiibie of various ~ formed with and opening through one- side of 50 base wall 2li. The sleeve 23 is formed inward- ' -‘ modiñcations and alternative constructions, I the ly from its outer end with- a counterbore 24 ter have shown in the drawings and will herein de 445 Io--I'o' ci Fig. l. Fig. 11 is a. vertical sectional view taken along in a square annular shoulder 25 inside scribe in detail the preferred embodiment. but it, l.minatingV of the' wan zo, end is adapted snugly :c receive is to be understood that I do not thereby intend" 55 toiimit the invention to the specific form dis- 'the discharge endcf the mervduct 1,2 with the 1st- „5 2 > ter secured tightly against the shoulder. 2, 1 1 6,774 The fuel conveyor I3 terminates in the horizontal inlet of the chamber 22, and in operation causes the entering. fuel as fed to force the bed of fuel 1n the chamber gradually upwardly. Mounted on the fuel chamber 22 is a tuyère structure, the interior of which constitutes an upward continuation of the fuel chamber 22. The tuyère structure comprises a bottom tuyère ring 10 26, a plurality of intermediate tuyère rings 21 nested on the bottom ring, and a top tuyère ring 28 resting on the uppermost of the intermediate rings, the rings being of gradually increasing diameter upwardly. Preferably, the rings 26, 21 and 28 are flat in form, with the bottom ring 26 resting squarely on an outer marginal ñange 29 on the upper end of the fuel chamber 22, and with each of the other rings 21 and 28 resting re spectively upon the ring next below. 20 A plurality of spaced radial slots 30 defining intervening seating pads 3| are formed in the underside of each of >the rings 26, 21 and 28, and preferably each has vertical radial sides and a root surface flared upwardly at both ends so as 28 to define air inlet passages of varying cross-sec tion when the rings are in nested' relation. The slots 30 may be of -any suitable width and spaced drical in form. vTwo inner peripheral grooves 44 and 45, defining an annular inner rib 46, are formed in the end 43~of the Wall 40. The groove 44 receives an outer peripheral flange 41 on the upper end of a base ring 48 which is mounted on 5 and bolted to an inwardly extending annular flange 49 on the upper edge‘of the base wall 20. , The tuyère structure defines an annular air space 50 for supplying air under pressure through the'inlet passages 30 into the fuel chamber 22. The bottom of the annular space 50 opens be tween the flanges 29 and 49 into a large plenum chamber 5I defined by the base wall 20. One side of the wall 20 is formed with a tangentially extending duct 52 alongside the sleeve 23, and in communication at its inner end with the plenum chamber 5I. The duct 52 is preferably rectangular in form, and is connected tothe discharge end of the air supply conduit I4. Ashes and other residual matter of combustion - are forced outwardly over the edge of the tuyère back 38 into the ash- pit I9 between the retort I0 and the furnace wall I8. To provide means for automatically removing the ashes, the 4side of the sleeve 23 opposite the duct 52, and the base wall 26 are formed integral with an upwardly open ing ash collecting chamber 53, preferably in the in any desired manner. In the present instance, ' form of a trough having front and rear end walls the slots 30 in each ring are relatively small but 30 equal in width in the half located forwardly or adjacent the duct I2, and relatively large but equal in widthl in the half located rearwardly or remotely of the duct, and are arranged in uni formly angular spaced relation about vthe periph 35 ery. I have found that by this difference in size of the vport areas of the‘slots 30, a superior fuel bed is obtained in that the unburned fuel is evenly distributed, by reason of the fact that the increased combustion at the rear due to the presence of more air compensates for any excess distribution otherwise tending to occur. Prefer ably, all of the rings 26 to 28 are provided with slots 30 having the same angular spacing, and with the widths of the pads 3| increasing pro gressively upwardlyv so that the corresponding 1 slots of the respective rings are of equal widths, and are nested in such a manner that the slots vand pads are located „in generally vertical tiers. 54 and _55. The front end wall 54 has an out 51 receiving the ‘iletlënd of the4 ash duct I1. The receiving end of the ash conveyor I 6 extends from the duct I 'I into the trough 53, and the base of the latter conforms generally to the cylindrical contour of the conveyor. 35 To direct the ashes into the trough 53, an ash ring 58 is mounted on the upper edge of the wall 28 for rotation about the base ring 48. `While the ring 58 hasa fairly close fit with the base ring' 48, it can be turned with very little power since 40 the rest of the retort is stationary, and since in the event of any temperature increase the tol erance is correspondingly 1increased through ex pansion. The ash ring 58 has an annular iiange 59 along its inner periphery extending upwardly into the groove 45 into overlapping relation with the lower end of the wall 46 of the tuyère Vbaci: 38, and a second annular flange 6I! at its outer periphery depending about the base wall 20 so Each of the tuyère‘rings28 and 21 is formed with a plurality of peripherally spaced upstand ’ as-to guard the bearing surfaces against the entry r ing lugs on the outer edgev -which snugly receive of ashes or other foreign matter. Formed on the and center the tuyère ring next above. In 4the outer periphery of the ring 58. are a plurality present instance, three. uniformly spaced lugs 32, 'of uniformly 'spaced radial vanes 6I `for moving ' 32 and 33 are provided, with the intermediate ashes lcollecting» about the retort III into the lugs 33 of -successive rings being located alterf trough 63. . ‘ nately at diametrically opposed points. Thabot 'I'he ash ring 58 may be driven vbyany suitable tom ring 28 has two spaced depending lugs 34 means, and in the present is adapted extending into notches 36 formed in the flange -to be driven continuously in instance one direction from 29. Formed on each >of the rings 21 and 28 be the ash conveyor I6. Thus, the flange 60 is tween the lugs 32 and diametrically opposite the formed with an internal gear 62 which is con lug 33, -and adapted to interfit with the lug 33 stantly in mesh with a «pinion 63 fixed on the of the ring 26 or 21 immediately vunderneath vso as 'to lock all of the rings against rotation are two closely spaced laterally extending lugs 31. . Mounted on the upper tuyère ringk 28 is a hol low tuyère back 38 having inner and outer walls. 39 and 40. Preferably, the tuyère back 38 is split into two ring sections which arebolted together `.when assembled. The inner wall 39 has a pe 70 ripheral flange. 4I fitting into an annular groove 42 inthe outer periphery of the ring 28, and iiares sharply, upwardly and outwardly, toward the >furnace wall I8. The outer wall 40 extends substantially below the wall 39, and converges 75 uniformly toward its lower end 43 which is cy1iri_-. upper end of a shaft 64. This shaft 64 is jour naled in a transmission/casing 65 (see Figs. 11 and l2) bolted to one side of the base wall 28 which togetherwith the bottom tuyère ring `26 is flattened to locate the pinion 63 inside the ash ring 58. Fixed on the'shaftl 64 is a bevel gear 66 which meshes with a. bevel gear 81 integral with a .shaft 68 extending through a bearing sleeve 68 on one end of the easing 65. A packing 70 collar 18 secured to the end of the sleeve 68 pre vents the -entry of foreign matter along the shaft 68 into the casing 65, and is located in an open ing 1I in the rear end wall 55 of the ltrough 5,3. The Shaft 68 has a square end 14 fitting in and 75 3 2,116,774 front wall, and vertical sides 98 and 89 with upper inclined edges. While the hopper walls may be joined in any suitable manner, preferably, having- a driving connection with a socket 15 in the end of the ash conveyor I8. The casing E5 is fully sealed at all points against the entry of foreign matter, and may be the front and rear walls 98 and 91 have vertical side flanges |00 overlying the side walls 98 and 8l, and the latter have side flanges |0| in the upper filled with a suitable lubricant through a supply tube 65“ normally extending to the exterior of the furnace. One wall of the casing il comprises portion of their rear edges engaging the inside of the rear wail. The top of the hopper || con a circular disk 65h which is provided with a pres 'stitutes the _supply opening |02, and is inclined, sure relief valve 85C for preventing overloading v with one edge lower as at the front wall 88, for 10 with the lubricant or grease. the convenience of the attendant in throwing in the fuel. Stokers are installed under widely varying con Means is provided for breaking olf clinkers at the edge of the retort I0 without spilling un burned coal into the ash pit I8. This means com prises two sweep arms 16 which are mounted in diametrically opposedV relation on the ash ring 15 58 for rotary movement therewith, and which ex dltions. In some instances, it might be extremely ^ inconvenient to charge fuel into the hopper || 15 from the frontend of the stoker. One of the tend upwardly almost to the edge of the tuyère back 38 and then rearwardly relatively to the direction of rotation and'upwardiy at a slight an ieatures'of the invention therefore resides in so break off the clinkers bylifting them, thereby re turning unburned coal into the ñre pot instead of cascading same into the ash pit I9. The fuel hopper || (see Figs. 1 to 3) comprises in shape so that the upper portion of the hopper may be orientated thereon as desired in any one constructing the hopper || that in lassembling the upper porton with ‘the base 11, the top open ing |02 and particularly the lower edge thereof gie to above the retort l0. While two sweep arms 20 16 are shown, it will be understood that only one may be orientated to best adapt it to the 'installa for which the stoker is intended. may be used if desired. 'I‘he arms 10 thus act to` tion illus, the top of the hopper base 11 is square a base 11 having a vertical rear wall 18, an in of four different positions. The upper edge _of ' the base 11 is formed on all sides with a marginal external flange |03.~ Each of the upper walls 98 to 88 of the hopper ,|| is formed along its lower clined forward wall 19, and.oppositely inclined side walls 00 _and 8| deñning an upwardly open ing generally V-shaped trough 82. Two depend edge with an inwardly facing g‘i'oove |04 adapted base 11, rest on a foundation 85 to support the Preferably, the groove l|04 is defined by striking the lower marginal portion of each wall to receiveV the contiguous section of the flange 30 ing brackets 03 and 84, on opposite ends of the hopper Vil andlits attachments. The front brack iìrst outwardly, then downwardly and then in wardly. In assembling the hopper il,> three of the upper walls, namely the walls 01, 88 and 88, are joined together into an integral structure, and are then positioned on the base 11 by sliding the4 grooves |04 of the two extreme walls Q8 and 99 longitudinally onto two spaced sections of the 40 flange |03 until the intermediate section of the et t3 is integral with and extends forwardly of the front wall 19, and is formed with an elon gated cylindrical bearing 88 in alignment with the apex of the trough 02. An external hori zontal sleeve t1 formed on the rear wall 'll and towhich the fuel. duct l2 is connected defines ' an outlet opening 88 also in alignmentl with the 40 trough 02. , The fuel conveyor i8 extends along the hopper trough 02 through the outlet opening t0 into thev duct l2, and the apex of the trough conforms generally to the cylindrical contour oí the conveyor vane. The' forward end ofthe . ñange interiits with conveyor il extends into and is guided and sup ported in the bearing 80. To secure the hopper base 11 in rigid assembly with the retortlll, the fuel duct l2 extends at its inlet end into a counterbcre I9 against a periph the groove of the interme diate wall 01. Then, the remaining wall, namely the wall 96, is secured to the-walls 88 and @9, with its groove |05 receiving the remaining section of the flange |08. The hopper top may thus be lo 'cated in any one of four different positions. In the position shown, the lowest wall 96 constitutes a straight continuation of the inclined base Iwall 19. A 50 eral end shoulder 90 in the -sleeve 01, and is vThe fuel and ash conveyors i8 and lo are adapted to be driven from a common source of i power, such as an electric motor |05, through a engaging with ears 02 on the ends of the sleeves transmission mechanism |06. In its preferred form, the mechanism |08 comprises a closed cas clamped between the shoulders 25 and 90 by means of‘three peripherally spaced tie rods 0| tt and el. ' _ « To afford convenient and ready access'to the 55 ` interior of the hopper base 11 where the conveyor ing .|01‘havìng a removable rear .cover sccticn |00. As a means of support, the cover section |08 is it enters the outlet opening 88, an opening $3 is formed' partly‘in the top of the sleeve 81 and partly in the wall 18 at the juncture. That part 60 of the opening 93 in the wall 18 may he viewed as an enlargement of thel outlet .opening 8l. An angular ‘plate` 08 is removably secured against provided externally with a generally circular flange |09 which constitutes a ‘clutch housing, and which is removably mounted at its outer peripheral margin on the supporting bracket 83 coaxially with the fuel conveyor I0 and bearing 86. A mounting plate ||0 is interposed between the ilange |09 and the bracket 03, and the parts are securely bolted together. The mounting plate ||0 extends substantially above the casing |01, and constitutes a primary the wall 10 and the top of the sleeve 81 toA close the opening 93, and- preferably vhas, an inward projection 95 to preserve the cylindrical contour of the outlet opening 88 and to denne an upper shearing edge coasting with the vane of the support for the’motor |05. ' Thus, the motor |0|i- conveyor i3. It will-be evident that'any obstruc tions coming between the shearing edge and the _is mounted directly on a horizontal supporting base plate |||, of which one end is pivotally se 70 conveyor vane and tending to stall the conveyor cured to the plate H0, and the-other end is con Y can quickly be removed through the opening Il v nected through a depending adjusting screw ||2 without emptying the hopper. l with an ear ||3 on the top of the casing |01. A The superstructure of the hopper |I an outwardly _inclined front wall II. a vertical rear wall ‘81 extending substantially above the 75 cover ||I for the motor |05 is mounted on the plate H0. VIt will be evident that through angu- u 4 9,1 16,774 lar adjustment of the plate III, the motor |05 movement on the rear end of the shaft I2I, can be located accurately in position to place the ‘ and is formed with a peripheral groove I 48-and proper tension on the drive belt. The transmission mechanism |06 comprises a $1 power inlet shaft |I5 which extends through and is journaled in a tubular enlargement I I6 on the front of the casing |01. One end of the shaft I I5 extends externally of the casing |01 for operative connection to the motor |05. In the present ln 10 stance, two sheaves ||1 and IIB, each with two V-grooves of diiferent diameters, are secured re spectively to the motor shaft |I9 and the shaft II5, and are connected by a V-belt |20 with side with two diametrically opposed clutch dogs or elements |49 on its rear face. A coupling |50 having a square end |5| in driving engagement in a socket |52 on the forward end of thefuel _ conveyor I3, is provided on its forward end with two diametrìeally opposed clutch dogs or‘ ele ments |53 adapted to coact with the elements |49. 'I‘he side faces of the coacting elements |49 and 10 |53 are undercut as shown so that the rotative force will tend to hold the elements tightly in engagement when in use. It will be evident that driving surfaces and interchangeably related to_ upon engagement of the clutch elements |49 and one or the other of the sets of aligned grooves to provide two selective speeds. » . An outlet or driven shaft I 2| (See Fig. 5) ex tends below and transversely of' the inlet shaft ||5 through the casing |01. Of the shaft I2I, 20 the rear end is rotatably journaled in a bearing |22 in the rear cover section |06, and extends to the exterior for -operative connection with the I 53, the drive connection from the inlet shaft I I5 15 to the outlet shaft I 2| will be completed.l The means for actuating the clutch sleeve |41 comprises a yoke |54 ñxed to a vertical rock' shaft |55 rotatably mounted in spaced lugs |56 « in the housing |09, and operatively engaging in 20 the groove |40. A hand lever |51 is pivotally secured to the upper end of theshaft |55, and fuel conveyor I3, and the front end is journaled ' is adapted to rock the shaft selectively to engage in a bearing`|23 in the front wall of the casing 25 |01. 'I'he front end of the shaft I2I normally is or disengage the clutch elements |49 and I 53. The free end of the lever |51 is adapted to be enclosed in acap |24 removably secured to the _ pivotally lowered to one side or the other of a Vfront of the casing |01, and engages an end thrust bearing |25 disposed against the front wall of the cap. Upon removal of the cap |24, a hand 30 tool (not shown) may be applied to a squared sec tion |26 of the exposed end of the shaft I 2| to turn it and the fuel conveyor I3 manually as may be necessitated on occasion. A second outlet or driven shaft |21 parallel to 535 the shaft I2I extends through the casing |01. Of the shaft |21, the rear end is journaled in a lug |58 on a horizontal plate |59 integral with the cover section |‘08 so as to lock the clutch sleeve |41 in either position of adjustment. By reason of the gear reduction between the 30 outlet shaft |21 and the shaft I2I, the ash con veyor I6 is always driven at a greater speed than the coal conveyor I3. Hence, the immedi ate and complete removal of ashes Without any likelihood of clogging and regardless of the rate of fuel supply ‘is assured. Upon opening the |49, |53 in the drive for the fuel conveyor to the exterior .thereof for operative connection clutch I3, the ash conveyor I6 and the' blower I5 still with the ash conveyor I6, andthe front end ex- ' can be driven to complete combustion of the fuel bearing |28 in the cover section |08, and extends 40 tends through and has a driving connection with a sleeve I29journaled 'in a bearing |30 in the front wall of the casing |01. "The rear end of the outlet shaft |21 is formed with a transverse _ bore |3I, and extends into a socket |32 in one end .45 of an extension shaft |33, wherein it is secured for a driving connection by means of a pin |34 ex tending loosely through the bore. Similarly, the other end of the extension shaft |33 has a trans ' verse bore I 35, and extends into. a socket |36 in the forward end of the shaft lof the ash conveyor ‘ I6 to which it is operatively connected by means of a pin |31 extending loosely through the bore. The front end of the shaft |21 and sleeve |29 assembly also extends to the exterior of the cas 55 ing |01, but normally is enclosed by a removable cap |30. _ Rigid with the inlet shaft |I5 is a worm |39 in the retortv I0 even though the supply of addi~ , 40 tional fuel is discontinued. Preferably, the drive connection between the sleeve |29 and the shaft |21 is automatically separable upon the'application of an excessive force. In the present instance, this connection 45 is _shown as a shear pin |60. Since both conveyors I3 and I6 are driven from the shaft |21, it will be evident that the single shear pin |60 serves to protect the gear transmission mechanism |06 and also the motor |05 in the event that 50 either or. both of the fuel and ash conveyors become obstructed. . ' The blower I6, which constitutes the source of air under pressure for supporting combustion, is not disclosed in detail since per se it forms 55 no part of .the invention, and generally comprises which meshes with a worm wheel |40 keyed to an _ a housing |62 -which is mounted on a bracket elongated sleeve |4| rotatable on the outlet shaft . 60 I2I. A gear, |42 also keyed to the sleeve I4I meshes with a gear |43 keyed tothe sleeve |29, thus completing the drive connection from the inlet shaft I|5 to the outlet shaft |21. The gear lng just described affords two substantial speed 05 reductions. Preferably the outlet shaft |21 alsoconstitutes a countershaft in the drive for the outlet shaft I2I. To this end. aysmall gear I 44 keyed to the shaft |21 meshes with a, relatively larger gear' |45 keyed to the shaft I2I. An anti-` friction bearing |46 is interposed between. the .cover section |06 _and the .gear |44 to take the end thrust ofthe shaft I 21'. To provide means for connecting the shaft I2I to the fuel conveyor I3, a clutch sleeve |41 in .75 the housing |09 is non-rotatably splined for axial |63 bolted to one end of the transmission casing |01, a rotor |64 driven directly from the shaft _of the motor |05, and a damper I 65 adjustable to vary the supply of air. A suitable blower is shown in the patent to May No. 1,834,959. A suitable guard |66 for the drives from the motor |05 to the transmission |06 and the rotor |64 is mounted on one side of the housing |62. The air conduit I4 (see Fig. 1) opens tangentially from the lower portion of the housing |62. Pref~ erably. the conduit I4 is substantially straight, rectangular in cross-section, and in the same horizontal plane as the fuel and ash ducts I2 and I1.- >A clean-out cover |61 may be provided in one side of the conduit I4, ' Since the air of combustion from the blower Il is supplied to the retort I0 under pressure, 75, 5 2,1 16,774 it is possible in the event of a poor draft that the pressure in the combustion chamber may build up very substantially `and tend to force obnoxious gases through the ñre pot 22, the fuel duct I2 and the fuel hopper || into the atmos phere. The pressure may also tend to force such gases outwardly through the ash duct |1. To obviate this serious difficulty, particularly where there is a poor or inadequate furnace stack (not shown), air pressure is maintained in the Vfuel and ash ducts I2 and |1, by con nesting same through by-passes with the air supply, sufliciently high to resist the internal furnace pressure. In the case of the fuel duct 15 |2, the by-pass comprises an opening |88 formed Y in the top of the sleeve 28 inside ‘the wall 28. A slot |88 is formed in the top of the discharge , end of the fuel duct I2 in communication with> the opening |88 so asyto connect the interior of .the duct with the plenum chamber 8|. The slot |88 is inclined inwardly toward the _nre pot-22 soasto directthejet of airtowardthclatter to build up kinetic as well as static resistance to the furnace pressure. -The by-pass-for` the ash remover comprises a by-pass line |18 com the ring |8| is formed with a counterbore |82 re ceiving the end of the duct |1 so that the duct is held in place by the endwise lock applied by the tie rods 9|. As an additional means of sup port, the duct> |1 may be strapped to the fuel duct `5 I2 by a metal band- |83. The second receptacle |15 is located at one side of the hopper base 11, and is ,secured thereto and to a flange |84 joining - the brackets 83 and 84, Connecting the adjacent end walls |19 and |18 ofthe receptacles is a short 10 duct |85 which is formed on one side of a bracket - |86 secured to the hopper base 11. The ash con veyor I8 extends from the duct |1 through the first> receptacle |14 and the duct» |88 into the second receptacle |18 where the screw vane ter- 15 minates. `The «shaft extension `|88 extends through the forward wall |18 of the receptacle |15 for connection to the conveyor I8 as described. A cap |81 on the wall-‘|18~about the shaft |88 and filled with mineral-wool serves to prevent the 20 escape of ashes. y 'I'he outer sides of both ash receptacles are open to receive removable ‘ash cans |88 and |88 l of similar shape. It will be evident that `when , the ash can |88 becomes iìlled, the ashes ,therein> 25 ' municating‘at one end with the plenum cham; form a passage above the conveyor |8 through . ber 8|, and connected at the other end to the _ which additional ashesare carried into the second 'ash duct |1. In the preferred form, the discharge receptacle ns. „Upon removing the asn san m to empty same, the second ash can |88 which end of the line |18 is connected to a e |1| formed in a bracket |12 secured to the ash may. be partially filled can be substituted there- 30 lduct |1. A slot |18 formed in the duct I1 at -fore in the receptacle |18.. If desired, each ash receptacle may have a an angleinwardly and toward the fire pot 22 hinged cover |88 secured »to the outer edge of the communicates with the inner end of the passage ` top ~wall |11-to facilitate removal or insertion |1| to complete the connection. . . „ . The ash duct I1 is connected at its discharge of the ash can. end to- ash receiving means comprising one or I claim as my invention: ` In a~s|;oker_,inv combinationl a ilrepot, a base more receptacles.4 Preferably, two receptacles |14 and |18,_ arranged in series, with the second wall deñning a .plenum chamber about said tire adapted to receive the overflow from the ñrst, are -.pot, a fuel supply duct opening through one side of' said wall to said me pot. an air supply duct `40 40 provided, and constitute in eilect a continuation ` opening to the same side of said plenum chamber. of the ash duct |1. i , Y Each of the ash receptacles |14 and |18 is a nest ‘of tuyère rings mounted on said p_ot, said rectangular in fo , and comprises a iioor |18, tuyère rings defining a plurality of peripherally air ports in communication with said a top wall |11, end walls |18 and'_|18 and an spaced inner side wall |88. Of the ñrst receptacle |14, chamber and opening to said ñre pot„the ports 45 lone end wall |18 is secured to the rear of the in the. side of said rings adjacent said ducts be bracket 84 under the hoppervbase 11, andthe ' ing smaller in eil‘ective area. than the ports Vin the other end wall |18 is connected to the- ash duct ' vother side of said rings. I1 by means of a flanged ring |8l. Preferably, ~ JosEPH HENRY WALTER.