US1352466A - Sylvania - Google Patents

Description

C. F. MILLER.

UNDERFEED STOKER ANO DRAFT CNTHOLLING MECHANISM THEHEOF. APPLmATmN men suit. :9, 191s.

1 ,$352,466- Panted Sept. 14, 1920.

HIS ATTORNEYSIN FACT,

lunirse sTArEsirATENT "ortica, l

cHanLEsF. MILLER, or rI'rrsBUnGH, ynmxsYtvemn, AssIGNon To WESTING- HOUSE ELECTRIC s Menumcrunme COMPANY, A CORPORATION or PENN# SYLVANIA. l

UNDEBFEED s'roxnn AND DeAF'r-coN'rnoLmNs MECHANISM cinnamon.

To allulwmz'may concern: l

Beit known that I, CHARLES F. MILLER, a

citizen of the United States, and a resident of Pittsburgh, in the zcounty'of Allegheny and State of Pennsylvania, havemade a new and' useful Invention in Underfeed Stokers Y and Draft-Controlling MechanismV Thereof, of which the following 4is a. specification.

This linvention relates to stokers, particu larly to under-feed stokers in which .the fuel is fed to the furnace at a surface of-the fuel bedr. 4

- An object of this invention is to produce an improved Stoker of the type described, in which new and improved means are employed for regulating draft to the furnace and at the same time for subjecting the grate bars to the cooling influence of the incoming air.

A further object is to produce an improved Stoker of the type described, in' which improved means are employed for mounting both the moving and stationary grate bars, so that the fuel feeding retorts or troughs may be removed without removing the grate bars or the fuel supporting members,V or interfering with their adjustment.

A further object is to produce a rate bar point` beneath the in which improved means are emp eyed for.

cooling the fuel supporting surfaces of the bar and at the same time for delivering regulable amounts of air under pressure to different parts of the fuel bed.

A further object is to produce a fue] supporting element or a grate bar, in which means are employed for receiving air under pressure at -two different points, and for de'- ivlering all of the air so received to the fuel These and other objects which will be made apparent throughout Vthe further description of this invention, are attained by means of apparatus embodying the features herein described, and illustrated in the drawings Vaccompanying 4and forming apart hereof. Y H

In the drawings 'Figure l isatransverse, verticahsectional view of a Stoker embody?V ing my invention, one-half being shown in section along the line A-A of 3, and the other, in section along the line B-B of the same figure'. ,F ig. '2 is a' fragmental per-` spective view illustrating the arrangement of air boxes employed in the Stoker embody- Snecilcatibn of Letters Patent.v Patented Sept. 14, 1920, ppimaup mea september It,` 1ere'- 'seria'im 120,9?9,

.ing my invention and also illustrating the method of mounting and of actuating'` tbc grate bars or fuel supporting elements.

Eig. Bis a fragmental perspective view of one air box. It yis well known to employ a horizontal fuel retort or trough, which ex tends from the front to the rear of tbc furnace, and into which fuel is forced by means y of plungers or a revolving screw. It is also well known to employ such a retort in connection with either inclined or horizontal fuel supporting members, such as grate bars, which are located on both sidesofthe retort and on topwliich fuel is fed from the retort by a crowding or upheaving action ofthe fuel, occasioned by the introduction of fresh fuel into the retort at a point below the surface of the -fuel, contained therein, or of the fuel, located on the fuel supporting members ofthe furnace. It is also old to employ movin@ and stationary grate bars, in connection with such a retort, which coperateto 'agitate orbreak up the fuel bed and to gradually move the fuel from the retort toward the outer end of the grate bars, or

toward the sides of the furnace. lt is also old to supply air under pressure to euch furnacesand to cause the air or blast to traverse air `passages formed within the grate bars or fuel supporting elements, but, so far as l lrnow, it is new to deliver all or substantially all of the air entering the furder pressure to the grate bars in two streams,

and to so construct the air or blast delivery passages of euch grate bai-'that each stream of air or blast will be delivered to arlilferentpart of thefuel bed. These novel feav tures form 4detallsor part of my present in ve'ntion Ymeans of a; plunger, from a hopper receptacle located at thefront and on the outside of the furnace.

The furnace also includes grate bars which are arranged in two sets, one set being loe'ited on one side and the other set on the other side of the retort The grate bars of each set are mounted on two air boxes which extend sulgistantially parallel to the retort and u liich supply air lo passages formed within the grate bars.

s illust ated the retort 3 extends lroni the trout to the rear of the l'urnarf '.inllis mounted on 'frames or pedestols i which are located at right angles to the longitudinal axis ot the retort and extend substantially across the furnace 'from our sil e lo the other. The girate hars or fuel supportin` elements 5 a re arranged in two sets, a set being located on each sido of 'the retort. 'The grr-ale bars of each set areA supported by two air boxes 6 and 7, which are inountedon the pedestals L lt- \\ill oi' rou '3c be understood that tivo or more pedestszls arr employed and that they are so spaced along the retort as io provide a rigid support for the retort, the rute 'oars und ull the operating;l parts ot the stoker.

is illust ated cach pedestal -l is provided with a recess, located midway between ils ends und in which the retort Il is mounted. As shown the retort consists of side walls 8 and a4 base plate 9. The side walls extend vertically, with their lower ends engaging longitudinally extending ribs l0, formed on thc pedestal, and they are bolted or otherwise secured to the pedestal. rlhe base plate 9 rests on the rib engaging anoes of the side walls S and is rigidly securell to the pedestals by Suitable nicans, not shown.

The air boxes 6 are located on opposite sides of the retort 3 and are mounted en the pedestal el in such positionsl that each supports the upper or inner ends oi' the grate bars of one set. Each air box 6 is substantially rectangular in crossscction and is provided with a longitudinal extending air duet which communicates` with blast delivery ports l2 formed iu the bar supporting surface of the box.

The air boxes 7 are located near the side walls of the furnace and each is so mounted on the pedestals l that it forms a. support for the lower or outer ends of the grate bars of one set. Each air box 7 is substantially channel shaped in cross-section and is adapted to deliver air to the grate bars1 supported by it, through blast delivery ports 1.4 formed in its bar supporting surface.

The pedestals 4 not only support the operating parts ot the Stoker but also forni spacers Jfor the blast or air delivery passages of the stolzer. The space below the retort and fuel supporting elements ot the stolzer is divided into three compartments or into chambers l5, 16. and 1G' by partition plates 17 which are mounted on the pedestals. The chamber 15 may be termed the primary air chamber and, extending' from the liront to the rear of the Stoker, is adapted to deliver air under pressure to the air boxes 6 and T. This chamber communicates with a blast delivery passage 18, which is shown located immediately below the retort 3, consequently the air delivered through thopassa-ge 18 is divided into two streams whiclrpafs to op posite sides of the furnace.

Air is delivered from the chamber l5 to the air boxes 6 through passages or ports 19 provided in supporting lugs 20 which are formed on the pedestal. Each supporting lugr 'forms a journal or bearing [or a. rock sha lt 2l and alsosupports one air ooX illustrated each air box 6 is provided witl a depending extension 22, in which` aport 23 is 'formed for delivering air from one of` the passages 19 to the interior passage of the box. Each bell' (3 is also provided with lon gitudiually extending ribs 24 which are spaced to correspond to the space of the pedestal l and whichare eonsequentlg. located immediately above the inlet portsl 22 with which the box is provided. These ribs rngage the upper 'face oi' supporting lugs 2l) ot different pedestals and cach boxis adapt.- cd to be clamped to the outer lateral face of its supporting lng by means of bolts or other suitable means so as to place the ports4 23 of the box in direct communication with the passages 19 of the pedestlals.

The air boxes 7 are mounted on the pedestals l in such a way that their Hang-reextend downwardly and subtend upwardly projecting mounted lugs 25 formed on the pedestal. lith this arrangement the open side of the channel section ofeachbox 7 is in le ,-onnnunication with the.- chaniher 15..4

'The grate bars 5 are substantially similar in erternal contour but; every other har ot cach set is adapted to reciprocate or to move fludinally toward und away from the retort. For this reason every other bar is provided withV downwardly projecting prongs 26 which engage the rock shaft 21 and through which the reeiprocatory motion, imparted by the rock shaft, is transmitted to the bars. The stationary bars are provided with downwardly extending lugs 27 which encrage opposite sidesof. the air box 6 and ho d the hars in place.

The air blast, delivered to the fuel bed, is rst passed through the grate hars "or the purpose of cooling the grate bars and at'the Same time preheating` the air. lnasniuclras each grate bar receives blast from two sources, namely, an airboxl'i. and an airbox 7, it is provided with two air passages which, as illustrated7 deliver` air to different parts of the fuel bed. Each port 120i the air boxes 6 communicates with air passage 28, formed in the retort end of one gratev bar. Each grate bar is therefore provided with an admission port, whichcornmunicates with the passage 28 and which is formed in that portion of the bar which engages the bar supporting surface of its supporting box '6.'

bers. 16 or 16, after the air haspassed' through the greater portion of the-bar. This is accomplished by providing an air 'delivery port 31, in each bar, which is located near the partition, separating the passages 3() and 28, and is adapted to discharge the air from the passage 30 downvvardlyint'o one of the secondary air chambers. `The inlet port to the passage 30 of each grate bar is formed in the face of the bar which engages the air box 7. The air deliveryr passages ,of the stationary and moving grate bars are similar. The ports 12 and 14 are so proportioned, With relation to the registering ports of the grate bars, that the flow of air into the movlng bars is not throttled by the reciprocati'on of the bars nor are the air ports in either the bars or the air boxes uncovered at any time during the motion of the bars,

The blast issuing from the ports 31 of the grate bars and entering the secondary air chambers passes upwardly between the grate bars and is delivered to that portion fof the fuel bed supported by them. For this Vreason the-bars are provided with spacing pads 33 which are located on each side oi' each bar and at each end thereof.

During the operation of the Stoker fuel Y issuing from the retort is chstributed over both sets of grate bars and the fuel bed assumes a contoursomewhat similar to the dotted line in Fig. 1. The reen fuel enters the thickest portion of the nel bed and consequently it is desirable to be able to control the supply of air to, this portion of the fuel bed independently of the air delivered to the thinner portions of the bed, located on the grate bars. This is accomplished by providing'a damper 34, in the primary air chamber 15 and between the air delivery passage 18 and each air box 7. As illustratet these dampers extend from the front to the rear of the chamber 15 and may be operated from the front of the furnace to cut down the air supply to the air boxes 7 and. consequently to the secondary air chambers and in this Way permit the blast to the thicker portion of the fuel bed to be in-4 creased Without the liability of blowing holes through the thinner portion. The continuous delivery of fuel into ,the retortL causes the fuel to distribute itself over the grato bars 5 and finally to be delivered on to dump grates 35, which are located on .each side of the furnace and extend from the frontto the rear thereof. illustrated the 'dump grates are pivotally .mounted on brackets 36 carried `by the air boxesj' and are located at the outer ends of the grate bars. The reciprocating motion of the moving grate lbars aids the distributing of fuel over the fuel supporting elements and also tends' to break up the fuel bed and feed the fuel downwardly along the'grate bars. `The ash and clinkers are discharged into the ash pit by lowering the dump gratos 35 and as illustrated each furnace is provided With twoash pits one located at'cach side thereof.

`The secondary air chambers 16 and 16' receiveV all the coal or fuel YWhich may sift through the openings between the grate bars or through the openingsbetween the inner ends ofthe grate bars and the upper edges of theretort. The pedestals dare so formed that each secondary air chamberis provided with two downwardly inclined Walls which terminate in a fiat floor 37.] Inasmuch as the secondary air chambers extend from the vfront to the rear of thefurnace the siftings may be readily removed therefrom by providing a door for each secondary air chainber which may be located in the front of'the furnace and may be of substantiall the same Width as the floor 37. It will a so be apparent that'this arrangement of the partition plates 17' prevents the coal siftings from interfering with the operation of the Stoker, since there is no tendency for it to interfere with the operationof the rock shaft 2] nor -is there any possibility of its entering the air chamber 15.

By supporting the grate bars on the air boxes it is possible to remove 'the retort Without in any way interfering with the adjustment of the grate bars and it is also possible to remove the grate bars and their operating mechanism without interfering with the op`- eration of the retort or its fuel feeding means.

The rock shaft 21 maybe operated by the usual form of stokerdrive mechanism, and,

it Will be apparent, While I have illustrated but one embodiment of mv present invention,

that various changes, modifications, substitutions, additionsy and omissions may be made in the apparatus illustrated 'Without departing from the `spirit and scope of the invention as set forth by the appended claims.

VVhat-I claim is:

1. An, underfeed stel-:er Comprising a rotort, and grate bars adapted-to receive fuel from the retort, each grate bar being provided With twyer openings at its retort end and a delivery passage communicatiu g there- Witlnand a separate air delivery portami a separate passage communicating therewith, means for dividing the space below the grate bars into a. primary and a secondary air chamber ant 'ineens for delivering air from the primary air Vchamber to the separate passages of each grate bar, the said air delivery port being adapted to deliver air to the said secondary chamber.

2. An underfeed Stoker comprising a retort, and grate bars adapted to receive li'uel ironi the retort, each grate bar being provided with tivrcr openings at its retort end and a delivery passage. ronnnunicating therewith, and a separate air delivery port and a separate passage communicating there with, means `For dividing the space below the grate bars into a primary and a secondary air chamber and means tor delivering air from the primary` air chamber to the separate passages of eachgrate bar, said secondary air chamber' receiving air through the ports formed in the grate bars, and eischarging theair between the grate bars into the t'uel thereon.

An underfeed stolier comprising fuel feeding retort, grate sms receiving *fuel therefrom, an air chamber beneath the bars adapted to discharge air between the bars into the fue-l thereon, each oi' the said bars being provided with a pair oi independent air passages, one of which discharges air into the said air chamber and two air boxes for supporting the grate bars, one of which is adapted to deliver air to one passage of each bar and the other of which is adapted to deliver air to the other passage of the bar.

4. An underteed Stoker comprising a fuel feeding retort, grate bars receiving Yfuel therefrom, an air chamber beneath the bars adapted to discharge air between the bars into the fuel thereon, each of the said hars being provided with a pair of in-lrgianzlent air passages, one of which disclinrgcs air into the said air chamber, pair oi air l :ers for supporting the grate bars, one oi" which is adapted to deliver air to one iliassage of each bar and the other of which is adapted to deliver air to the other passage oli the bar, and means for controlling the deliveryr of air through one of the said boxes;

5. An underfeed Stoker comprising a retort, grate bars adapted to receive fuel from the retort and supporting means Jfor the retort' and grate bars, each grate bar being provided at its retort end with twyer openings, an air passage for delivering air thereto, and an inlet port communicating with the passage, each grate bar being provided with a second inlet port located near the other end thereof, a passaffe communicating,T .vith the second port and extending throughout the greater portion of the bar and a delivery port located in the lower face of the bar and communicating with the last mentioned passage.

G. A grate bar having twyer openings formed in one end thereof, a )assage former therein and communicating with the oper ing and having an inlet port communicating therewith, a second passage formed in the grate bar, a delivery `port located in the lower face of the bar, and'intermediate its ends, and communicating with the second passage, and an inlet port located in the opposite end of the bar from the ta'yer openings and communicating with the second passage.

7. ln an underfced stoker, a iuel feeding retort, an ash discharge mechanism, a set oll grate bars located between the retort and said mechanism, two air boxes, one located adjacent the ash discharge mechanism and one adjacent the retort ends of the bars 'for supporting the bars and for delivering air under pressure to separate passages formed within the bars, a primary air delivery chamber located beneath the grate bars and communicating with each air box, a secondary air delivery chamber located im niediatcly below the grate bars and receiving air from the primary chamber through passages oi the grate bars.

S. An underfeed Stoker comprising a fuel feeding retort, a dump grate mechanism, a set ot grate bars located in parallel relation and extending from the retort to said incohanism, each grate bar being provided with two separate air delivery passages, onel having an inlet at' one end of the bar and an outlet adjacent the opposite end oi the bar adapted to discharge air beneath the bar, and the other an inlet intermediate the ends of the bar and outlet ports discharging into the iuel upon the bar, and two air boxes for supporting the grate bars and each delirrriug air to a separate set o'lair passages o? the bars.

9. )in underfeed Stoker comprising a Yfuel feeding retortf a dump grate mechanism, a set ol' grate bars extending in parallel relation and located bet-Ween the retort and said mechanism, each grato bar being provided with two separate passages, one hav infr an inlet .located intermediate the ends of the bar, and communicating with twyers formed in the retort end of the bar, and the other having an inlet formed in the ash discharge end of the bar and connnunicating with a delivery port formed in the lower face of the bar adjacent to the inlet to the Erst mentioned passage,two airboxes for supporting said grate bars, each delivering air under pressure to one of the inlets of everu bar, pedestals on which said retort and air boxes are mounted, and partition plates mounted on the pedestal and dividing the space below the bars into a prin'iary air chamber communicating directly with both air boxes, and a4 secondary air chamber located immediately below the grate bars and receiving air from the air delivery ports located in the bottom of the grate bars.

i0. An underfeed Stoker comprising a centrally located retort, an ash discharge mechanism located on each side of the retort and extending parallel therewith, a separate set of grate bars located on each side of said retort and each extending from the retort toward an ash discharge mechanism, each grate bar being provided with two separate air passages, one having an inlet formed near the ash discharge end of the bar and an air delivery port iiormed in the lower face of the bar intermediate the ends thereoithe other passa-ge having an inlet formed near the retort end of the bar and communicating with twyer openings located in the retort end of the bar, two air boxes for supporting each set of grate bars, each delivering air to one inlet or each bar of one set, a pedestal on which Said retort and all said air boxes are mounted, and partition plates mounted on tlie'pedestal and dividing the space below the furnace into a primary air chamber, 'which communicates with all the air boxes, and two secondary chambers, each being below one set oi' grate bars and receivingair from the air delivery ports of the bars under which it is located., 1

1l. An underieed Stoker comprising la central retort, two ash discharge mechanisms, one located on each side of the retort and extending substantially parallel therewith, a separate set of grate bars between the retort and each o4 said mechanisms, each grate bar having two separate air passages formed therein, one having an inlet at tie ash discharge end of the bar and communicating with an air delivery port located in the bottom of the bar intermediate the ends thereof, the other having an inlet located intermediate the ends of thc bar and communicating with twyer openings located in the retort end of the bar, two air boxes on which each set of grate bars is mounted, each communicating with one inlet of each bar supported thereon, a pedestal on which all the air boxes are mounted, partition plates mounted on the pedestal and dividing the space below the air box into a primary air chamber which communicates with all the air boxes, and 4two secondary air chambers, each of which communicates with the air delivery ports ofthe bars under which it is located, and Vmeans for separately controlling the delivery of ai secondary air chamber. Y

V communicating inlet registered located immediately f comminiicating with 4pedestal structure,

to each l2. ln combination y projecting lug formed thereon provided with an' air deliverypassage, partition plates mounted on the' pedestal vforming an air chamber with the said passage, an air box mounted on said lug and having an with the said passage, and grate bars supported, on said air box provided with air assages adapted to receive airirom the sai box. i

13. An underfeed stolzer comprising a fuel feeding'retort, grate bars receiving uel therefrom, an air chamber beneath the bars adapted to discharge air between the bars into the fuel thereon, each bar being provided with Aa pair of independent air passages, one of which is adapted to discharge air into the said chamber and the other of which is adapted to discharge air into the fuelupon the bar,l and a separate air box eachv passage of the grate barand 'adapted to deliver air to the f passage in communication therewith.

stoker comprising a 14;'A`n nderfeed pedestal construction having supporting elements Vfor two groups of grate bars and an intermediate retort, a ricd bysaid retort supporting elements, and a group of removable grate bars supported by said grate bar supporting elements at each` side of the retort.

l5. An underfeed Stoker comprising a a central retort, grate bars removably carried by said pedestal structure` wall elements carried by said Y in an underfeed` Stoker, a retort, ,a pedestalfsupporting the retort and `having an upward removable retort car pedestal structure and, together with the reg tort, deiininga primary air chamber, the

wall elements beneath'the grate bars defining secondary air chambers, each grate bar having independent passage-ways communicatingwith the primary air chamber, one discharging continuous to the retort discharge and the other discharging into a` secondary air chamber, said secondary air chambers beingcovered Vby the grate bars whereby the preheated air therein may escape between bars to support combustion.

mln testimony whereof I have hereunto subscribed my naine this 18th day of September, 1916.

.l CHARLES F. MILLER.

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