US2581037A - Feeder apparatus for spreader stokers - Google Patents

Description

Jan- 1, 1952 H. G. MElssNER ETAL 2,581,037

FEEDER APPARATUS FOR SPREDER STOKERS I Filed July l, l1949 A 2 SHEETS- SHEET l J ,f4 I i 1 G /8 'a 'lNvEN-roRs F' l Harold G. Melssner g BY George P. Jackson 4 5 ATToR EY Jan. 1, 1952 v r H. G. MEISSNER ET AL 2,531,037

FEEDER APPARATUS FOR SPREADER sToKERs Filed July 1, 1949 v v 2 SHEETS- SHEET 2 INVENTORS Harold G. Meissner George P. Jackson Patented Jan. 1, 1952 Y 2,581,037 FEEDER. ArPAtA'rUs FOR SPREADER TOKER Harold G'. Meissner', MountV Vernon, and vGeorge P. `ackson, Flushing, N. Y., assignors to Combuston Engineering-Superheater, Inc., New York, N. Y., a corporation of Delaware Application July 1,1949, serial No. 102,412 Y A soiaims. lol. 222-43461) This invention relates to apparatus for feeding fuel and other granular materials that tend tov pack and it has special reference to the fuel feeder portions of spreader stokers as employed fork the burning of coal and other-fuel in a furnace'.

An important object of this invention is to improve the design andi better the performance of fuel feeders which utilize a rotating assemblage to control the advance of coal' or other fuel intoy the spreader stokers whirling distributor blades.

Another object is to providea rotating feeder assemblage which is constructed and arrangedA so as to dislodge any fuel that adheres to ysur-- faces with which the fuel comes into. contact while advancing.

A further object ls to make .possible the securing of a satisfactory feedzwith. fuel that contains a high percentage of surface moisture or for other reasons has an inherenty tendency to pack.

An additionalobject is to improve the uniformity with which the feedersr rotating assemblage releases the fuel into the whirling distributor blades ofthe Stoker'.

Still further objects and advantages will become apparent as theldescription hereof proceeds.

Illustrative embodiments or" our invention are disclosed by the accompanying drawings wherein:

Figure i is a sectional elevation through part of a spreader Stoker that has the new scrapertype rotary feeder of this invention. installed therein;

Figure 2 is a section on line 2-2 of Figure l showing one satisfactory manner in which the new feeders rotating assemblage may be constructed and arranged;

Figure 3 is a. representation in sectional elevation of our new scraper-type feeder organized somewhat differently and supplemented by a spill plate which improves the uniformity of fuel release; and y Figure 4 shows further details of the spill plate represented in Figure 3.

In the installation shown by Figure l fuel such as coal flows from a supply hopper lil to a throat or passage l between a coal plate i2 forming a part of the feeder housing and one curved sidel (the left in Figure l) f a stationary feeder cyllnder I3. Feeder flights or bars i4 are advanced (counterclockwise in Figure l) around this stationary cylinder or drum i3 to move the fuel through passage ll and drop same from the lower edge of plate l2 between the impeller blades I6 carriedby the stokers'fuel distributor shaft l1; suitable meansincluding a plate it prevent fuel leaving hopper lo from reaching distributor lB--il by Way of the other side- (right in Figure l) of feeder cylinder I3. This hopper id is shaped` and' dimensoned so that even very wet coal will freely advance by gravity into contacto/ith' feeder cylinder i3 without bridging between .thewallsorother parts of the hopper.

Conventional driving facilitiesy which may.r include a line shaft t9 rotate the stokers distributor shaftV il'Y at'proper speedY (such as severalfhundred R". P. M.) and direction. (counterclockwise in the. underthrow arrangement of Figure 1) to. rapidly whirl the impeller blades Vif and thereby cause them to propel the fuel along tray 2t' and discharge same through opening 2| into the furnace. The ratev of: suchV introduction-of the fuel into the furnace thus is dependent upon the rate` at which the fuel is delivered by the. feeder lS--M to the revolving. distributor blades I6; and the rate of such fuel delivery to the ldistributor blades ymay bev controlled by adjusting the speedwith which the feeder flights M are moved around cylinder i3, or by adjusting' the dimensions ofv the throat ii opposite the feeder |3.-i`a when the flights thereof ar-e driven at' constant speed, or by .a combinationof these two adjustments.

. rThe feederassemblage shown at. t--iti' inFigures i--2v isV mounted on a shaft 24 journaled' in bearings 25 thatare carried. by the end walls 26 of. ther feeder easing'. One endv of shaft'4 24 communicates with rotating means generally designated at 21 (see Figure 2); in practice these means 2l may take any one of a number of conventional forms such as` mechanism (not shown in; detail) driven by' the stokers line shaft lilV ure 2) rand bearings 3B carried therein. TheseV hubs 29 may satisfactorily be fitted into' the cylinder Aends: and there welded in place as shown; bearings 3l] may taire-the form ofsleeve bushings treated with graphite to render them self lubrieating; and closure'gaskets 3l are preferably pronearly midway of cylinder I3s length and isv there secured (again as by welding) to the face of an inner shroud ring 34 that encircles cylinder i3 in a manner permitting rotation relative thereto.

Each set of members 33-34 with interconnectlng flights I4 thus constitutes a cage structure which rotates with the feeder shaft 24, the direction of such rotation being oounterclockwlse in the representation of Figure 1. This illustrative cage arrangement of Figures 1-2 utilizes four flights I4 equally spaced around the circumference of cylinder I3 and each taking the form of an L-shaped angle bar having its leading edge held either in contact with or very close to the cylinder surface in the manner shown. In moving around the curved cylinder surface each flight is thus effective to scrape same free of all adhering fuel; moreover, the angular cross section of. the ights adds desired rigidity to each cage structure 33-I4-34 and makes same capable of transmitting driving torque to the individual flights without causing inner shroud ring 34' to lag rotatively behind the outer hub-like cage plate 33 that is keyed to the feeder shaft 24.

Feeder flights of other cross sections and designs are of course useable at i4 and either more or less than four may be included in each cage structure. Furthermore the two cage structures embracing feeder cylinder I3 may have their flight bars I4 rotatively aligned as here shown (see left and right of Figure 2) or the flights I4 of one cage structure may be angularly displaced (as by from those of the companion structure. Only the former arrangement is represented here.

In order to restrain the feeder cylinder I3 from rotating with the cage structures 33-I4--34 and the feeders drive shaft 24, there is attached to the cylinder (as by Welding) an arm 35 which projects outwardly from the cylinder surface between the inner shroud rings 34 of the two cage.

structures and which bears against a bracerpipe or tube 36 that spans the feeder casing as indicated in Figure 1. As shaft 24 drives feeder flights I4 around the curved surface of cylinder I3 the accompanying torque imparted to the cylinder holds restraining arm 35 against stationary pipe 3B and thus prevents the cylinder from rotating with the shaft 24 by which it ls carried.

, How the scraper-type feeder apparatus of Fig- Y ures 1-2 operates will have become evident from the foregoing description. Coal or other fuel to be burned in the furnace is placed in hopper I 0 and carried by gravity downwardly against stationary cylinder I3 and into the passage I I therebeside. While the stokers distributor blades I6 are rapidly spun (to throw fuel supplied thereto into the furnace through opening 2I the feeder shaft 24 is rotated (as by means 2l) at an appropriately slow speed and advances the feeder flights I4 around (counterclockwise in Figure l) the curved surface of cylinder I3, the latter being held stationary by armw35. In so advancing tionary cylinder I3' take the form of bars rather through passage II each flight I4 moves a quantlty of the fuel thereahead for droppage from the edge of plate I2 into the whirling distributor blades I6. The flow of fuel through the feeder to the stoker distributor I-I'I thus is at a rate substantially proportional to the speed at which the feeder cage structures 33-I4-34 are rotated by shaft 24.

VA fuel feeder so organized in accordance with our invention can successfully handle a wide range of fuels and offers the very practical advantage of assuring uniform feed with coal or ,other fuel which contains a high percentage of surface moisture. Past attempts to burn such high moisture fuel with spreader stokers equipped with feeders of conventional non-scraper design have been accompanied by serious operating difficulties caused by: (a) coal hanging up in the Stoker hopper so that the flow to the feeder is either irregular or completely stopped; and (b) coal clogging the feeder with the result that it either discharges the fuel irregularly in slugs or becomes ineffective and feeds no coal. Moreover, these difficulties (experienced with prior art spreader stoker feeders) became troublesome when the moisture content of the coal is increased to only about 10 or 12%. A

But, the new scraper-type feeder here disclosed has been found to overcome the foregoing difficulties with striking success. As earlier indicated, the fuel hopper I0 now utilized is proportioned to be free flowing so that even very Wet coals will pass under their own weight downwardly into contact with the feeder parts I3--i4 without hanging up in the hopper. And once having reached the new feeder assemblage even the wettest of coal can be successfully advanced therethrough at a uniform rate and without clogging. Reason for this success is that movement of each feeder flight I4 around stationary cylinder I3 is accompanied by a scraping action which effectively frees the cylinder surface of the wet fuel particles that otherwise would adhere to the cylinder and to the flights themselves were the scraping action not present.

Referring next to Figures 3 and 4, a second embodiment of our invention is there illustrated as being applied to a spreader stoker whose dis-v tributor blades I6' are spun by shaft I I in the clockwise direction to provide an overthrow" discharge of fuel into the furnace through opening 2l'. The scraper-type feeder assemblage shown in Figure 3 corresponds generally to that earlier disclosed by Figures 1-2 but differs therefrom in that the flights I4 surrounding stathan angle pieces, the cage structures including these bars are by feeder shaft 24, rotated clockwise instead of counterclockwise, the restraining arm 35' carried by the cylinder I3 bears against the lower edge of a plate 38 (curved beneath the feeder cages) to resist clockwise rotation of the cylinder, and a spill plate 39 for giving more uniform release of fuel from the feeder is disposed along the cylinders discharge side (right in Figure 3) close to the circumferential edges of scraper bars I4 and in the path of fuel droppage from therebetween.

Except for the variations just indicated theA satisfactorily duplicate the corresponding assemblage of Figures 1-2; in which event it-will thence to outer hub-like. case plates 3.3'y that are keyed .to feeder shaft 24.' ,for .reception of'l driving. rotation therefrom. .Said shaft 24'Y may be. rorated by any suitable means 21A (general des.- isnation details not shown) at an. appropriately slow speed which is adjustable and whichV provides clockwise motion as viewed ln Figure, 3. The resultant angular advancement ofthe feed-v er shaft and cage structures will here be assumedto be continuously progressive rather than inter-1 mittent or step-by-step. Obviously the. feeders twoy cage structures (left and vright in Figure d). may have been their night bars i4' rotatively aligned as here shown or these feeder bars one structure may be angularly displaced from those of the companion structure.

arrangement represented in Figures S-a enables fuel from hopper l0' to reach whirling distributor` 552-43' only as a result of advancement downwardly around the curved right (Figure 3) side of the feeder-s stationary cylinder i': downward passage of fuel` around the other (left in Figure 3) side of the cylinder. being suit. ably blocked by xed plate 38v and the` upward motion of feeder bars i4 therealong.

Froper entrainrnent of a quantity of the fuel ahead of each feeder bar is' advancing downwardly around the cylinders. right sideis facilifated by equipping the top of the feeder assemblage with aA out-o plate- 4l mounted; to swing beneath a support shaft 42 against the torque exerted by a counterweight 43. Said torque normallygholds platel 4I. in the position. shown but permits yielding movement thereof towards the right) if individual lumps ofy fuel pushed ahead of the feeder bars i4 requireV same during bar passageY beneath plate. Ms. lower edge.. Eect is to` level off the.` segments of fuel that. are car-.. ried between adjacentV feeder bars il# down.- war-diyl around stationary.- clyinder i3." and' intov of a shaft or rodi llfifrom. which they plate hangs;

so. as normally tolie against thecircumferential edges-` of the feeder, bars, it! that. move. downwardly-around the. cylinders right side..y Qbviously supplemental meansv (asa spring or weight. not shown) may be usedto assist.r gravityA murg-4 ing. plate.- Sii; towards cylinder t3'.

This` spill plate 39, is; provided. with. avv lower orl fuel-release edge (best, shown` in Figure 4) which is inelined1yshapedWith. respect to the aforesaid feeder bars lfthat. pass under the plate (see Figure 3); the shaping here illustratively indicated involving a progressive downward lengthening of the plate from a highpoint- 4t at the plate center to low pointsl :il at each plate side` -Other equivalentinclinations of the fuel-release edge l'I-!6'-l'1 may of course be employed.

AIn operation of the feeder apparatus o f- Figures 3-4, coal or other fuel to be burnedin the furnace is placed in hopper Hland carriedby gravity downwardly against the stationary' cylinder i3. While the stokers distributor blades IG are rapidly spun (to throw fuel fed thereto into the furnace through opening 2I'), the feeder shaft 24 is rotated (by means 21A) at an appropriately slow speed so as to advance the iiight bars I4 around (clockwise in Figure 3) the curved surface of stationary cylinder I3. In so moving each bar advances a. quantity of the fuel beneath eut-.offV plate 4.1. and thencey downwardly into. resister with. thespill plate 38.. Release, of fuel by that spill. plate. fromv each fuel quantity between. adiacent feeder. bars. I4* begins at the. plates center (see Figure 4) and then progressively spreads outwardly towards the plate sides as the bar Mi further moves downwardly; byy thetime. the. outer ends of one set of-.bars have been exposed at 4'! the following set of barsthereabove have. comey into register with the plates high center 46; and in this way the. fuelis dropped from between the` bars I4' into the stoker distributor` |6'.-I1 at a. substantially uniform rate relatively` free from pulsations, assuming thatfeeder shaft Ml moves flight; bars. I4 around cylinder I3 ata substantially uniform speed. 1

.rIf desired there. may be.- placed beneath spill plate. 39 above distributor.` lf-..I'|'r a deflector plate. 49 upon whichA the fuel: released fromv the.

feeder drops before entering .the overthrowwhirling blades.. l6 of the distributor. Setting of the represented inward slope ofv this plate 49 for optimum effectiveness maybe accomplished.

by moving adjuster slide 5U` forward or back.- ward beneath clamp nutrl v From theforegoingit will beseenthatgwe have improved the design and better-ed the performance-.of fuel feeders which utilize a rotating as.- semblage to control. the advance. of coal or other fuel into. aspreaderwstoker; that, we have provided rotating feeder assemblages. whichV dislodge surface-adhering fuel and enable satisfaotoryfeedingv of fuels containing a high percentage of moisture orl for other reasons having an inherent tendency to pack; and .that wehave; improved the. uniformity with which the fuel. isv released from the feeders rotating assemblage.

Our invention accordingly has broad.V utility and hence not tovberestricted tov the. specilc forms here disclosed by: way. of illustration.

What we claim is:l

i. In a feeder for delivering material through a passage, the combination of a rotatable shaft extending across the passage between the loca.-

4 tions of material entry thereinto and of material discharge therefrom a cylinder-surrounding said shaft in concentric' relation thereto with the cylinders curved sides. spaced from adjoining boundaries of the passage; meansrestraining said cylinder against rotationy with. the shaft,V said.

means including a member protrudingoutwardiy from the cylinder for engagement with. astationary. stop; a cage. structuremounted in concentricv relation` to .saidcylinder for rotation with said shaft and. including scraper bars. that extend longitudinally along the outside surface of the cylinder in:Y spaced' disposition around thecylinders periphery, said `cage structure. surrounding the portion. of said. cylinder that between. said.

restraining member and one-.ofthe. cylinder ends; means including said shaft for rotating said cage structure whereby to advance.: the scraper bars thereof around the cylinders stationary` surface and forwardly through; the said space between one of. the cylinder-s eurvedsides and the adjoining passage boundary'so that each bar can advance material ahead thereof through that space and in thus moving over the cylinder surface can prevent material from adhering thereto and accumulating thereon; and means preventing forward travel of material past the cyllnders other side.

2. In a feeder for delivering material through a passage, the combination of a shaft extending assi-,cav

across the passage between the locations of ma terial entry thereinto and of material discharge therefrom, a cylinder surrounding saidY shaft in concentric relation thereto with the cylinders curved sides spaced from adjoining boundaries of the passage, means for restraining the cylinder from rotation, said means including a member protruding outwardly from said 'cylinder at a point intermediate itsL length, a rst cage structure surrounding the portion of said cylinder that is between said restraining member and one of the cylinder ends and including scraper bars that extend longitudinally along the surrounded cylinder surface in spaced disposition around the cylinders periphery, a second cage structure surrounding the yportion of said cylinder that is between the restraining member and theVK other cylinder end and including scraper bars that extend longitudinally along the surrounded cylinder surface in spaced disposition around the cylinders periphery, means for rotating both of sai-d cage structures whereby to advance the scraper' bars thereof around the cylinders stationary surface and forwardly through the said space between oneof thecylinders curved sides and the adjoining passage boundary so 4that each bar can advance material aheadjthereof through that space andl in thus moving over the cylinder surface can prevent material from adhering thereto and accumulating thereon, and means preventing forward travel of material past the cylinders other side. L"

3. In a feeder for delivering material such as fuel through a supply passage leading generally downwardly, the combination of a horizontally disposed shaft extending across said passage; a cylinder also spanning the passage and surround ing said shaft in concentric relation thereto with the cylinders curved sides spaced from adjoin ing boundaries of the passage; means for restraining said cylinder from rotation with the shaft, said means including a member protruding outwardly from the cylinder for engagement with a stationary stop; a cage structure mounted in concentric relation to said cylinder for rotation with said shaft and surrounding the portion of said cylinder that is between said restraining member and one of the cylinder ends, said cage structure including scraper bars that extend longitudinally along the outside surface of the cylinder in spaced disposition around the cylindei-s periphery and that are attached to a hub member secured to said shaft adjacent said one cylinder end; means including said shaft and hub member for imparting to said cage structure rotation which advances the scraper bars thereof around the cylinders stationary surface and downwardly through the said space between one of the cylinders curved sides and the adjoining passage boundary so that each bar can advance fuel ahead thereof through that space downwardly and in thus moving over the cylinder surface can prevent fuel from adhering thereto and accumulating thereon; and means preventing ilow oi fuel past the cylinders other side.

4. In a feeder for delivering material such as fuel through a supply passage leading down- Wardly, the combination of a horizontally dis-f posed cylinder extending across said passage with its curved sides spaced from adjoining boundaries of the passage and there supported against rotation,ra cage structure mounted in concentrically surrounding relation to said cylinder for rotation with respect thereto and including scraper bars that extend longitudinally along the outside of the cylinder in spaced disposition around the cylinders periphery, means for imparting to said cage structure rotation which moves the scraper bars thereof around the cylinders stationary surface so that fuel can be advanced ahead of eacn bar downwardly along one side of the cylinder, means preventing ow of fuel past the cylinders other side, and a spill plate disposed along the cylinders said one side close to the circumferential edges of said downwardly moving scraper bars and in the path of fuel droppage from therebetween, saidspill plate having a lower fuel release edge inclined from parallelism with the scraper bars which pass under the plate whereby when the cage structure is rotated at a substantially uniform speed fuel will be dropped from between the scraper bars at a substantially uniform rate relatively free from pulsations.

5. In a feeder for delivering material such as fuel through a supply passage leading down` wardly, the combination of a horizontally disposed cylinder extending across said passage with its curved sides spaced from adjoining boundaries of the passage and there supported against rotation, a rotatable structure including scraper bars that extend longitudinally along the outside of said cylinder in spaced disposition around the cylinders periphery, means for imparting to said structure rotation which moves the scraper bars thereof around the cylinders stationary surface so that fuel can be advanced ahead of each bar downwardly along one side of the cylinder, means preventing ow of fuel past the cylinders other side, and a spill plate disposed along the cylinders-said one side close to the circumferential edges of said downwardly moving scraper bars and in the path of fuel droppage from therebetween, the lower or fuel-release edge of said spill plate being inclinedly shaped with respect to the scraper bars which pass under the plate whereby rotative advancement of those bars l around the cylinder at a substantially uniform speed will cause fuel to be dropped from between the bars at a substantiallyuniform rate relatively free from pulsations.

HAROLD G. MEISSNER. GEORGE P. JACKSON.

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

UNITED STATES PATENTS Number

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