US2164100A - Underfeed stoker - Google Patents

Description

UNDERFEED STOKER Filed Jan. 14, 1956 5 Sheets-Sheet 1 June 27, 19%39. R( ZINKERNAGEI. Err Al. 2,154,100

UNDERFEED sToKER Filed Jan. 14, 1956 5 Sheets-Sheet 2 /.m ATTORNEY June 27, 1939.

R. ZINKERNAGEL ET AL UNDERFEED STOKER Filed Jan. 14, 1936 Lf-15.12'. 'tr

5 Sheets-Sheet 3 ATH'ORNEY June 27, 1939 yzlruklzmmslal. ET Al. 2,164,100

UNDERFEED STOKER Filed Jan. 14, 1936 5 SheeLS--Shee'll 4 rum- INVENTORS ATTORNEY June 27, 1939.- R. ZINKERNAGEL" ET AL. 2,164,100

UNDERFEED sToKER 5 Sheets-Sheet 5 Filed Jan. 14, 1936 INVENTOR ATTORN EY Patented June 27, 19.39

PATENT OFFICE UNDERFEED STOKER Richard Zinkernagel, New York, and George P.

Jackson, Flushing, N. Y., assignors to Combus- Y tion Engineering Company, Inc., New York,

Application January 14, 1936, Serial No. 59,046

7 Claims.

This invention relates to stokers and particularly to the multiple retort underfeed type.

The invention contemplates, in a multiple retort Stoker, a novel assembly of parts so arranged as to cooperate to eifect eicient combustion of the fuel thereon, which parts do not interfere with each others individual functioning.

An object of the invention is to provide a common pusher actuating means for each retort cooperating with individual pusher control means, said control means being independent in control from said actuating means.

A second object of the invention is to provide a novel controlling means for the common pusher t actuating means for each retort as well as for the individual pushers.

`Another object of the invention is to provide a novel pusher construction.

Another object is to provide cooling means of the structural supporting means of the tuyres and retorts.

A further object of the invention is to provide a novel and simple means for the orientation of` the major stoker parts during their assembly, said orienting means serving as major supporting and orientingstructure for said major stoker parts.

t Still another object of the invention is to provide an overfeed section construction adapted to minimize clinker formation.

How the foregoing, together with' such other objects and advantages as may hereinafter appear, or are incident to our invention, are realized, is illustrated in preferred form in the 1 accompanying drawings, Wherein:

Fig. l is a longitudinal sectional view of aV stoker constructed in accordance with the invention;

Fig. 2 is an enlarged, partly sectional, view of the forward end Yof the Stoker showing the arrangement of the orienting beams and also the common adjusting control for operating the pushers of a retort; v

Figs. 3 and 4 are sectional views on the lines 3 3 and 4 4 in Fig. 2 andillustrate the` construction of the common adjusting control for the pushers of a retort;

Fig. 5 is an elevational view `of the orienting` beams for the retorts as seen from the right 5` hand Sideof Fig. 2, some parts being omitted Fig. 7 is a sectional view on the line 1 1 in Fig. 6, partly broken away showing the construction of the retorts and tuyres;

Fig. 7A is a sectional view taken on the line 1A TA in Fig. 7;

Fig. 8 is a side elevational View, partly in section, of the overieed section located beyond the retort illustrated in Fig. 6, and shows the control means for variably regulating the operation of the moving grate bars;

Fig. 9 is an end view, partly sectioned on line 9 9 of Fig. 8, of the overfeed section;

Fig. l0 is a plan View, partly in section, showing the construction of the auxiliary rams or pushers; and

Fig. 11 is a sectional View along line Il ll in Fig. 10 illustrating the individual controls for regulating the movement of the pushers and also showing the construction of `the latter.

Referring to the drawings, the numeral I designates one of a plurality of columns spaced at suitable intervals across the width of the Stoker` and-supporting the main beams 2 and 3 which run transversely of the Stoker. In the arrangement shown, the beam 2 is a channel beam lying in a vertical position and forming part of the front wall of the Stoker. The beam 3 is an I` beam mounted horizontally near the top of beam 2 so that the meeting flanges of the beams form right-angle surfaces 2a, 3a that serve as an orientation means for the major parts of the stoker. Fastened on top of beam 2 and also to beam 3 are face plates 4 having cast integral therewith the main ram cylinders 5, there being one face plate for each retort of the stoker. Ram box sides 6 are bolted at right angles to the face plates 4 and have secured thereto the forward ends of beams l which at their rear ends rest freely in saddles 8 carried by the rear main supporting beam 9, Fig. 8, thereby providing for freedom of expansion and contraction. The beams 1 form the main longitudinal supports for the tuyres and adjoining retorts and also for parts auxiliary thereto, as will be apparent as the description proceeds. The orientation of the beams 'l by attachment to the ram box sides 6 which in turn are oriented by being secured to the face plates 4 that are fitted to the rightangled surfaces 2a, 3a formed 'by the beams 2, 3 results in the upper end faces of lthe beams 'I being located in the same plane so that these beams are parallel and thus enables all of the` parts of the alternating retort and tuyre sections of the Stoker to be simply and accurately oriented with relation to each other.

The beams 1 are of box girder construction and constitute air boxes for the superposed tuyres, the beams being reticulated on their upper and lower faces to provide for the passage of air into the tuyres from the air chamber I beneath the Stoker. Sectional side plates for the retorts and tuyres are secured to the beams 1 as by bolts I2. The plates are spaced from the beams to provide air gaps I3 between the sides of the beams and the plates. rest upon beams 1 at intervals, as by feet I4, leaving air spaces I between the feet |4. Air may pass from the chamber |0 beneath the stoker around the air boxes |2a below the tuyre blocks through the air gaps I3 and spaces I5 and into the tuyres at all times, that is at banking' periods when the air dampers to the tuyres are closed as Well as during other periods. Thus, the beams 1 are cooled on both sides by the incoming air for combustion during al1 periods of operation and are thereby protected from overheat- The space at the bottom of each retort between its side plates is spanned at intervals longitudinally thereof by supporting plates 20 on which ridethe auxiliary rams or pushers 2 I, in this Acase four in number. The plates 20- are yieldingly fastened to the bottom flanges of the side plates to allow movement for expansion that may occur. The pushers 2| are adjustably connected, for selectively regulating their stroke, as will be described later, to individual brackets 22 allxed to a rearwardly inclined reciprocable beam- 40, except the forwardmost pusher 2|, which as shown in Fig. 2, is carried by rod 14 connected to the forward end of beam 40 vfor actuating the latter.- Rod 14 and beam 40 together constitute a pusher bar for reciprocating the-pushers and the sliding grate bars 5|. Beam 40 is fixed at intervals to plate members 4| formed with trunnions 4 Ia provided with rollers-42 guided between upper and lower tracks 43, 44 supported by brackets 45- depending from the longitudinal beams -1.

The-overfeedY section ofthe stoker comprises alternated fixed andmoving grate bars 50,-5l, respectively, the latter havingslots 52, engaging a transverse rail 53. These bars may befeither solid -or of hollow construction.l Similarly to pushers 2|, the` operating stroke of rail 53 Vand hence of-bars 5|,-is variable-as will be set forth later. The reciprocating movement of these bars is effectedin one direction through a member 54 operatively connected to the reciprocable beam 4D 4andin the other direction by means of a rod 55 -xedly connectedaty one end to the beam.

The main ram' 60, the auxiliary rams or pushers 2| and the grate bars 5| of each retort receive their-motion indirectly from a crank shaft driven by any suitable means, as a system of selective reduction gears, which in turn are driven by a motor. The ram 60 is driven by the usual crank and crank pin 6| through a connecting rod 62 carrying a wrist pin 63 for actuating the ram. Crank pin 6| also operates a bell crank 66 through a connecting rod 61, a pin and slot connection 68, 69 betweenfthese parts providing lost motion and reducing the amplitude of motion imparted to the bell crank 66. Y

Bell crank 66 carries a pin 10 extending into,

which togethervwi-th rod 14 constitutes a common` The side plates |IY pusher bar for the four pushers 2| and the alternate, sliding grate bars 5| corresponding to the related retort.

The operating stroke of the pushers and grate bars have a common adjustment comprising a multi-step cam 15, xed to a shaft 13 extending parallel to the rod 14. Shaft 13 is positioned close to the push rod so that part of cam 15 is always in the path of movement of pin 10. On rotation of cam 15 its steps 16 may be selectively interposed between the head of rod 14 and the pin 1D mounted in a link 10a pivotally carried by bell crank 66 that operates the rod to vary the amount of movement imparted to rod 14 from the ram. Cam 15 is adjusted from the front of the stoker by a hand wheel 11 indexed to correspond with the steps of the cam. The motion of hand wheel 11 is transmitted to cam 15 through shaft 13 which has a telescopic section 13a formed with a slot 13b in which a stud 13s is engaged so as to permit reciprocating movement of cam 15 with rod 14 while providing for rotative adjustment of the cam by hand-wheel 11. The reciprocating part of vshaft 13 is supported by bracket 18 as shown in Fig. 3. Thus, by adjusting cam 15 to selectively position the steps thereof to take up more or less of the amount of lost motion permitted by the slots 1| in clevis 12 before pin 1U is effective to advance the rod 14, the extent of rearward movement imparted to rod 14v and beam 40 for advancing the pushers 2| and grate bars 5| may be varied.v The pusher bar 14, 4U, and hence the pushers and grate bars, are returned forwardly to their starting positions by pin on bell crank 66 engaging links 12 at the forward end of the slots 1|.

Each pusher 2| comprises a skeleton cradle 23 which lies below the two upper plate castings 24, 25 constituting the two steps of the pusher which advance the fuel down the stoker. At either side of cradle 23 and below plates 24, 25 are pusher side plates 26 which are independently free to move sideways and are held against the retort sides II by means such as springs 21 thereby preventing the-'passage of siftings between the pusher andretort sides. The plates 24, 25 are removable for replacement and interlock with sideY plates 26 at 28 and with each other at 29. The sidek plates 26 .iny turn interlock with cradle 23 and are moved thereby back and forth. A cam 3|] (Figs. 10 and 11) is mounted on a shaft 3| carried by the related bracket22 on the reciprocable actuating beam 40 which constitutes the pusher bar. Cam 30 has stepped surfaces 32, four steps in this instance, any one of which may .be placed in position to contact and push cradle 23 forwardly by revolving the cam into position manually through the respective indexed hand wheel 33 and shaft 3|. The different steps provide a variable lost motion between the cam 3|)andV cradle 23 and, consequently, a variable stroke of thepusher. The return stroke is caused by bracket 22 engaging the hook 34 on bolt 35, the bolt in turn drawing the cradle 23 forwardby its collar 36 engaging a shoulder of the cradle provided therefor. Cradle 23 is formed with a vertical slot 31 andwhen bolt 35 Yis revolved through about 180 deg., hook 34 will be in a position where .it will pass throughI said slot when .the-bolt is withdrawn. Likewise, hook 34 willpass through the slot in bracket 22 so that with the release of the bolt the cradle may be drawn to the right Fig. 1lv and the entire pusher 2 IJ with Lit-and free fromy beneath vthe pusher supporting plates 20-for the pusher above. ' Ihe step plates 24, 25 of the pusher may then be removed by revolving the top plate 24 slightly clockwise around the rearward end of bolt 35 and lifting it rearwardly clear, and then lifting off the plate 25 which forms the lower step. Cradle 23 may then be removed if necessary as well as side plates 26. By these novel means the pusher parts may be easily renewed from the furnace side, of the Stoker, Suitable seals are provided at the front edge of the pusher to reduce the siftings and air leakage which would otherwise pass by.

The different steps of each cam 3l] provide a variable lost motion between beam 46, bracket 22 thereon and the related pusher cradle 23 and consequently enable the stroke of each pusher 2I to be variably regulated independently of that of the others although all receive their motion from the main rod I4 and beam 40 common thereto.

'I'he member 54 for reciprocating the alternate movable grate bars 5I is guided in a bearing 56 and at its forward end is selectively engageable by the steps of a cam 5l similar tothe cams 30 for the pushers 2|. Cam 5l is rotatable by a shaft 58 operated from a hand wheel at the front of the stoker. Thus, the cam steps which are positioned at different distances from the forward en'd of member 54 may be selectively aligned therewith so that the travel of the movab-le grate bars 5I may be varied as in the case of the pushers 2 I. The rod 55 connected to and moving with beam 4D is provided with adjustably positionednuts 59 engageable with the rear end of member 54 for returning rail 53 and hence the grate bars 5I on the forward stroke, the adjustability of nuts 59 permitting a lost motion in the stroke. The overfeed section of the present Stoker moves each alternate grate bar- It has been found that greater agitation of fuel results, with resultant avoidance of clinker adhesion and a better air distribution with better burning. The difficulty of adjacent parallel movements of groups of bars involving a considerable area is completely avoided. It has been found that there is a more uniform transition of fuel flow from the retorts to the overfeed section and a more uniform flow of fuel across the overfeed section. The clinker adhesion that occurs in the group movement does not occur with this new overfeed section.

The shafts 3|, 58 for adjusting the stroke regulating cams 36, 5'1 of the pushers 2I and reciprocable grate bars 5| all reciprocate as a unit with the rod 'I4 and beam 46. In order that the hand wheels on these shafts may be stationary, that is non-reciprocating, telescopic sections 3Ia, 58a, similar to those of shaft 13 (Fig. 3) are provided to transmit the motion of the hand wheels to the shafts through lugs operating in slotted lug ways, lubrication therefor being provided through the hollow portions of the shaft. Universal joints Blu, 58u are provided for transmitting motion through angularly disposed portions of the shafts. The shafts 3|, 58 are supported beneath the retorts by brackets 46 depending from beam 40, as well as by the brackets 22 thereon adjoining the pushers. As described above, the beams 40 are reciprocatingly supported beneath the retort by the trolley members 4I guided on the tracks 43, 44 carried by the main longitudinal box guides l. As shown in Fig. 2, the shafts 3l, 58 extend through bearings 4l,

mounted on or adjacent to the main transverse beam 2, that serve as air seals.

Air for combustion enters the chamber I 0 common to all the tuyres which are disposed transversely of the stoker and extend longitudinally thereof between the retorts. This chamber is limited by the Stoker front which is located in alignment with the main transverse beam 2, and extends rearwardly below the rear supporting beam 9 to beneath the overfeed section of the stoker. As mentioned above the longitudinally disposed box girders form air boxes for the tuyres. It may be desirable to have control dampers at the bottom of the supporting beams I4 under each tuyre whereby the air to each tuyre or portion thereof is independently controlled.

The arrangement of parts of our improved stoker provides .a common` pusher actuating means for each retort, the stroke of which may be varied, cooperating with individual and independent pusher control means for each pusher and for the overfeed grate bar control means.

What we claim is:

l. In a stoker having a retort, a plurality of pushers therein, a reciprocable pusher bar connected to said pushers and a member for operating said bar; pin and slot means providing a lost motion connection between said member and said pusher bar; means for variably regulating the movement imparted to said bar through said connection comprising; a shaft extending adjacent said bar and member; a cam slidably keyed to said shaft and formed with a plurality of portions varying in length in the direction of movement of said bar and adapted to be individually disposed between the said pin of said connection and said pusher bar for regulating the extent of reciprocation of the latter.

2. In a Stoker having a retort comprising side plates and intervening bottom plates on which pushers are reciprocable to feed fuel along the retort; a pusher in said retort comprising; a frame or cradle; stepped plates mounted on said cradle for supporting and advancing the fuel; side plates freely mounted on said cradle below said stepped plates; and means carried by said cradle urging the side plates of said pusher against the side plates of said retort.

3. In a stoker having a retort comprising side plates and intervening bottom plates on which pushers are reciprocable to feed fuel along the retort; a pusher in said retort comprising; a frame or cradle; stepped plates mounted on said cradle for supporting and advancing the fuel; side plates freely mounted on said cradle below said stepped plates; and springs mounted transversely of said cradle and arranged to exert pressure against said pusher side plates for urging them toward the side plates of said retort.

4. In a stoker; a plurality of spaced retorts comprising side plates extending longitudinally of the Stoker with intervening bottom plates adjacent the lower edges thereof in each retort; tuyre blocks supported by the adjacent side plates of contiguous retorts; beams extending longitudinally of the Stoker below said blocks and disposed adjacent the lower portions of the outer sides of said side plates and spaced therefrom for providing air passages between said beams and plates; and feet at intervals on said side plates intermediate the top and bottom edges thereof resting on the tops of said beams to mount said plates thereon and providing openings along the top of said beam between said feet communicating with said passages-for admitting air flowing through said passages from below said retorts tothe space above said beams and below said tuyre blocks for coolingrthe upper portions of the outer surface of said side plates.

5. In an underfeed stoker having a retort including spaced side plates extending longitudinally of the stoker and bottom plate disposed therebetween; a pusher for said retort comprising; a frame or cradle adapted to ride on said bottom plates and having a forward portion of greater height than its rear portion; a step plate mounted on the lower rear part of said cradle and having an angular portion extending downwardly over the rear side of the lower portion of said cradle; a lug or ange on the forward edge of said plate; a second step plate mounted on the upper forward part of said cradle and having an angular portion extending downwardly in front of said upper part and of the forward flange on said first plate to lock the latter on the cradle; a downwardly extending lug or flange on the forward edge of said second plate lockingly engaging the forward face of said cradle; a reciprocable push bar for actuating said pusher; a bracket on said push bar formed on its upper face with a slot extending longitudinally of the pusher; means carried by said bracket and engageable with said cradle for moving it in one direction; and a bolt extending through the angular portion of said second plate and having a lugthereon engageable with said cradle and a portion lying in the slot in said bracket with a second lug at its forward end engaging said bracket for moving said cradle in the opposite direction.

6. In an underfeed Stoker having a retort including spaced side plates extending longitudinally of the stoker and bottom plates disposed therebetween; a pusher for said retort comprising a frame or cradle adapted to ride on said bottom plate and having a forward portion of greater height than its rear portion; a step plate mounted on the lower rear part of said cradle and having an angular portion extending downwardly over the rear side of the lower portion of said cradle; a lug or ange on the forward end edge of said plate; a second step plate mounted on the upper forward end part of said cradle and having an angular portion extending downwardly in front of said upper part and' of the forward end flange on said first plate to lock the latter on the cradle; a downwardly extending lug or flange on the forward end edge of said second plate lockingly engaging the forward end face of said cradle; a reciprocable push bar for actuating said pusher; a bracket on said push bar formed on its upper face with a slot extending longitudinally of the pusher; means carried by said bracket and engageable with said cradle for moving it in one direction; and a bolt extending through the angular portionof said second plate and having a lug thereon engageable with said cradle and a portion lying in the slot in said bracket with a second lug at its forward end engaging said bracket for moving said cradle in the opposite direction, said bolt being rotatable in said bracket slot for disengaging said second lug from said bracket to permit said pusher being disengaged from and moved away from said bracket.

7. In a stoker having a retort, a pusher mounted for reciprocation therein, a reciprocable pusher bar and means for actuating the latter; a bracket iixedly carried by said bar for moving said pusher rearwardly in said retort; a rotatable shaft supported by said bracket for Varying the movement of said pusher; a rotatable member mounted on said shaft and interposed between said bar-carried bracket and said pusher, said member being formed with a plurality of steps symmetrically disposed about said shaft and varying in length axially of said shaft for selectively engaging said pusher on rotation of said shaft to vary the movement of said pusher by said bar; and means carried by said pusher and engageable by said bar-carried bracket for moving said pusher forwardly.

RICHARD ZINKERNAGEL. GEORGE P. JACKSON.

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