US1406884A - Stoker - Google Patents

Description

C. F. MILLER.

soKER..

AFFLICATION HLED UG.3I. 1917.

Patented m14, 192g.

His A TTO'RNEYSIN FACT UNITED ksrrmrs PATENT OFFICE.

CHARLES F. MILLER, OF MORTON, PENNSYLVANIA', ASSIGNOR TO WESTINGHGUSE ELECTRIC & MANUFACTURING- CO., A CORIEQRATION 0F PENNSYLVANIA.

incassa.

Specification of Iietters Patent. Patented Feb. 14:, 1922.

Application filed August 31, 1917. Serial No. 189,200.

To all whom t may concern: y

Be it known that I, CHARLES F. MILLER, a citizen of the United States, and a resident of Morton, in the county of Delaware and State of Pennsylvania, have made a new and useful Invention in Stokers, 4of which" the following is aspeciication.

This invention relates to mechanical stokers and more particularly to stokers operating on the underfeedIprinciple. Underfeed stokers are usually provided with at least one retort into which green or fresh fuel is fed at a point below the air supplying passages to the furnace, sor that the fuel entering the furnace is subjected to the heat of combustion before it enters the combustion zone and before it is supplied with adequate air to support free combustion. By introducing the fuel into the furnace in this way some of the volatile constituents are distilled olf and the fuel is partially or wholly converted into coke before reaching the combustion zone, where sutlicient air is delivered to the fuel to support free combustion. It is, of course, understood that the volatile constituents distilled from the incoming fuel are/not lost, but are mixed with sufficient air' to promote complete combustion as they pass through the combustion chamber of the furnace. In order to vobtain complete combustion of the coked or partially coked fuel it is customary to cause it Ito pass over an overfeed section before it is discharged from the furnace into the ash pit. For the purpose of this specification, the term overfeed section may be defined as a fuel supporting Inember across which fuel is fed and to which air is so delivered that it enters the furnace below the fuel supported on the member.

An object of my present invention is to produce a new and improved mechanical stoker of the combined underfeed and overfecd type. y

A further object is to produce an underfeed Stoker in which new and improved means are employed for completing the combustion of the fuel leaving the underfeed portion of the Stoker.

A. further object is to produce a mechani cal stoker to which fuel isv fed at a point below the air supply to the ycombustion chamber and in which new and improved means are employed for distributing the fuel over the fuel supporting elements as it moves toward thev discharge end of the stoker.

A further Objectis to produce a stoker in `which improved means are employed for mounting fuel supporting members and for delivering the consumed fuel on to the dump f grate mechanism. y

A further object is to produce an improved power actuated dump grateinecha.-

msm.'

A further object is to produce an under-k feed stoker in which improved means are.

employed for aiding the delivery of fuel into the retort.

These and other objects are atta-ined by means of apparatus'embodying the features herein described and illustrated in the drawings accompanying and forming a part hereof.

In the drawings: Fig. 1 is a transverse sectional view of a Stoker embodying my invention.

Fig. 2 is a `fragmental transverse sectional Fig. 5 is a fragmental vperspective view illustrating the rear ends of several grate bars and the means remployed for mounting them on the stoker frame.'

ln a copending application entitled Underfced stokers,7 filed May 2l, 1917, and serially numbered 169,932, l have illustrated and described a Stoker which is similar to the stoker herein illustrated in that it includes an underfeed section comprising a retort l0, which extends across the front of the furnace and to which fuel is fed, at points below the air or blast admission pas sages, by means of fuel feeding plungers l1. rl`he plungcrs are located at the front of the furnace and are actuated by a fuel feeding alsI mechanism also located atthe front of the furnace. The fuel after entering the retort is delivered on to and across an overfeed section, illustrated as including a series of alternatingly` arranged reciprocating and stationary grate bars 12 and l2 vwhich exi tend from the retort- 10 rearwardly toward the dump grate mechanism 13 ofthe fur-A row and is mounted on the inclined table 16, which forms the floor of the retort 10. Each body 15 includes a fuel hopper 17 located at the front of the furnace, and a fuel delivery passage which establishes communication between the lower end of the hopper and the retort 10 and -forms a guide in which one of the plungers 11 operates. Each body also includes an air box 18, the rear and air delivery wall of which forms the front wall of the retort 10. The inclinedtable 16 may also be formed in short sections for convenience of manufacture and assembling, and its forward edge is shown mounted on a box section 19, which preferably extends the width of the furnace and forms the lower wall of the Stoker. The rear edge of the inclined table is mounted on a support bar 20, which ex-v tends across tlie furnace and is mounted at intermediate points on pedestals 21. The pedestals are suitably mounted on. frame members 22,-which are supported by suitably spaced beams 22a forming` the foundation frame of the stoker. The grate bars 12 and 12 are shown inclined downwardly from the retort 10 toward the rear of the furnace. Each bar is mounted at its upper and forward ends on a support plate 21, which extends fiom one side wall to the other of the furnace and which is supported at intermediate points on the pedestals 21. lower ends of the grate bars are mounted on an element 32 which forms a part of the air box 24.

Partition plates 26 are mountedv on the frame members 22 and divide the space below the fuel supporting members into two chambers 25 and 25a; the former of which may be termed the primary air chamber, since it receives air under pressure through conduit 27 and delivers it to the air box 24" The Air from this chamber is-delivered to the fuel bed through spaces located between the grate bars. Air from the chamber 25a is also delivered to the air box 18, as described in my\previous application.

One feature of my present invention is the new and improved means for mounting the lower ends of the grate bars. As illustrated, a bracket 30 is mounted on a channel 31 which forms the rear member of the Stoker frame and which in turn is supported on a' vbeam 22a. The bracket 30 performs a threefold-function; that of supporting the dump grate mechanism; of partially enclosing the air box 24; and of supporting the lower ends of the grate bars 12 and 12. The grate bars, however, are not directly mounted on a bracket 31, but are mounted on the member 32, which is pivotally mounted on the bracket. The member 32 is preferably formed in short sections, (see Figure 5), which. are so arranged as to forni the rear wall of the air box 24. As illustrated, each sect-ion of the member 32 consists of a web' having cylindrical top and bottom flanges. The lower flange is mounted in a suitable bearing, provided on the bracket 30 and is so arranged that the member'is .capable of rocking in its'bearings in response' to the reciprocating motion of the grate bars. The lo'wer end of each moving grate bar is provided with downwardly projecting lugs 32a and 32h adapted to engage the upper flange of the member 32 and each bar is preferably so supported by the member that it moves free of the front wall .of the air box. With this arrangement the moving bars impart motion to the sectional member 32. The stationary grate bars are provided with lugs 12n and 12b, which respectively engage the plate 21" and the forward wall of the air box- 24.- and prevent the bearing from moving. The rear end of each stationary grate bar vmay be wholly or partially supported on the moving member 32 and, as illustrated, is provided with downwardly projecting lugs similar to the lugs 32a and 32h of the moving bars. but which are spaced sufliciently far apart to permit the member 32 to move in both directions throughout its entire travel, without tending to impart motion to the stationary bars.

Reciprocatory motion is imparted to the moving grate bars by means of a rocker bar 34 which is similar to the rocker bar inthe application to which I have referred.

For the purpose of breakingup the fuel as it enters the retort, I have provided an apron 35, which is scured to the forward ends of the moving grate bars and which overlies a portion of the inclined table 16. This apron is preferably formed in short sections, eachV section somewhat less in width than the width of the retort body. As illustrated, each section is secured to one moving grate bar by means of a hinge connection, which permits the forward edge of the apron to move across the surface of the table and at the same time causes the apron to move with the grate bars.

Jknother feature of the invention is. the

dump grate mechanism and the operating apparatus forming a part of that mechanism. As illustrated, the stoker is provided with a single leaf dump grate 36- which is preferably, though not necessarily, formed in section corresponding in width to the width As illustrated in the present application' .I and as described and illustrated in the apmounted, and also operatively connected toplication to which I have referred, the stoker is provided with an operating shaft 38,

which is suitably mounted at the Ifront of the Stoker and which act-uates the plungers 1l through the agency of gear and rack connections. Power is also delivered to the moving grate bars from the shaft 38 by means of a lever arm which engages and is adapted to impart reciprocatory motion to a rod ex tending through the front wall of the stoker. This rod in turn imparts motion to the rocker bar 34.

As illustrated, the actuating mechanism of the dump grate 36 includes a lever or arm 39 rigidly mounted on the shaft 38, an ad justable connection 40, pivotally connected to the arm 39 and also to a bell crank lever 41. The lever 41 imparts motion to a link 42, which in turn, actuates/a rod 43. The link imparts reciprocatory motion to the rod, which motion is imparted to the grate 36 through the agency of a rack 44 mounted on the rod, a gear 45 meshing with the rack, and a link 46 operatively connected to the gear, or to the shaft on which the gear is the grate bar 36.` In the apparatus illustrated, the shaft 38 is periodically turned back and forth by means of a motor 47, and a connecting rod 48 actuated by the motor, and pivotally connected tofa'n arm 49, rigidly mounted on the shaft'38. ,W'ith such an arrangement the amplitude of the arm 39 is constant and consequently the apparatus actuated by -the arm 39 would operate to fully openand again close the dump grate 36 each time the shaft 38 completed a cycle of operation. In order that the operation of the dump grate mechanism may be independently controlled and also that the grate may be moved to any desired dumping position, I have provided manually adjustable means, which in effect operates periodically to break the operative connection between the dump grate mechanism and the actuating arm 39,\or which may be so adjusted that the arm 39 may oscillate without actuating thedump grate mechanism.

As illustrated, this is accomplished. by means of the member 40, the operation of which is controlled by a sleeve 5l, which surrounds a portion of the member 40 and is capable of being moved to different posi.

tions by means of a woim 52, a segmental gear 53, an arm 54, a link f' and a pivoted frame 56, to which the sleeve 51 is secured byl means of a pivotal link 57. The frame 56 is pivotally mounted on a vbracket 56a secured tothe front of the stoker and the operating shaft 58 ,of theworm 52'is journaled in this bracket and is provided with 'a hand wheel 59, which is so located as to be convenient to thestoker operator. The gear 53 is suitably mounted on a pin 60, which is shown mounted on the bracket 56a. In Figure 3 of the drawings the arm 54 is shown split or formed in two parts, both of which are'v integrally formed with hub portion of the gear 53. The frame 56 is shown bifurcated lat its free end and two links 57V are employed between it and the sleeve 51. 1

As illustrated the member 40 includes a rod 61, which is pivotally secured to the arm 39 and projects downwardly into av tubular casing 62 provided at its lower end with a pair of dogs 63. These dogs are normally pressed inwardly or toward each other by means of a spring 64 and are adapted to engage notches formed in the lower end of the' rod 6l and to thereby lock the rod and the tubular casing 62 together. The tubular casing carries two trunnions 62a which form an operative connection between the -member 40 and the bell crank 41. The bell crank 41 is shown in the drawings as a double bell crank, the separate parts being mounted on the pin 60*on opposite sides of the gear 53 so that eachengages one of the oppositely located trunnions 62" of the casing 6 2.

As-is apparent from the drawing, the arm 39 imparts reciprocatory motion to the tubular casing 62 when the dogs 63 are in engage ment with the rod 61. The normal dumping operation is as follows: The hand wheel 59 is turned so as to raise the frame 56 and consequently the sleeve. 51 to such position that it will not be engaged by the dogs 63 as they move 'in response to the motion imparted to the casing 62 by the rod 6l. Un-

Iback and in a clockwise direction'.

place during the upward movement of the arm 39 or as the rack 44 is moved outwardly and the gear 45 is moved in a counter clockwise direction. The positioning of the arm 45a wit-h relation to the final position of the gear 45 and also with relation to the link 46, causes the dump 36 to first move up-wardly before it starts to move downwardly to dump the refuse and ash contained on it. This up ward swing is of material advantage, since it breaks clinkers free from the bridge wall and aids the dumping operation. As Vthe arm 39 moves downwardly the gear 45 moves swings the grate 36 upwardly to the dot-dash posit-ion indicated above tothe full line position of the grate and finally causes the grate to move downwardly to the normal position. The amount of opening motion imparted to the dump grate mechanism in controlled by the position of the sleeve 51, which operates to engage the dogs 63, as the tubular casing 62 moves upwardly, and to thereby move' the dogs outwardly and out of engagementwith the rod 61. This breaks the operative connection between the arm 39 and the dump grate mechanism. In order that the dump grate, when so released, will not fall by gravity to the extreme dumping position, I have provided a stop 64a between the two parts of the bell crank lever 41, which is so positioned that it is adapted-to engage.

the arm 54 at the time the dogs 63 are released by the sleeve 51. lilith such an arrangement the stop 64n is held against the arm 54 by the weight of the dump grate and consequently the dogs 63 are held outwardly by means of the sleeve 51 until the rod 61 completes its upward stroke and in returning moves the casing 62 downwardly with it,by reason of the'fact that its lower end engages a stop 65, which is provided at the lower end of casing 62 and obstructs the passage through t-he member 62. As soon asthe rod engages the stop, motion is again imparted to the dump grate mechanism and the dump grate consequently starts to move toward the closing posit-ion. This motion releases' the dogs 63 from the sleeve 51 and consequently causes the dogs to engage the rod 61. lVhen the sleeve 51 is in an intermediate position the dump grate is `periodically opened and closed and each opening and. closing motibn causes it to move upwardly above its normal closed position. The amount of opening movement is determined by the posit-ion of the sleeve 51.

When it is desired to retain the grate 36 in the closed position the wheel 59 is turned to move the parts actuated by it to the positions indicated in Fig. 1. Nith the framer56 and consequently the sleeve 51 in the posif tions shownin Fig. 1the rod 61 moves back and forth within the tubular casing 62 without imparting motion to the casing and con- This sequently wit-hout imparting motion to the grate 36, since the sleeve 51 holds the dogs 63 out of engagement with the rod 61. `With the parts in this position there is no tendency for the grate 36 to move' downwardly to the dumping position since a posit-ive stop may be provided to hold the grate in the normal ently of the stop 64, and consequently the sleeve 51 may be adjusted for the purpose'of causing grate to openwithoutthe necessity of manually moving the grate.

Another feature of the invention is the method of delivering air to the dump grate 36. This grate is provided with an interior air passage which extends from the forward to the rear edge of the grate and supplies air to twyers 67 located in the fuel supporting face ofthe grate. In addition to this, the twyers are so arranged that they direct the air delivered through them across the face and toward therear of the grate. One or more twyer openings 68 are formed at the edge of the dump grate and are so arranged with relation to the interior air passage that ashes or fine materiah` sifting back through the twyers 67 will beblown out of the air passage through the twyers 68. Air is delivered to the .interior passage of the grate through an opening formed inthe pivoted end of the grate, which is adapted to register with an air delivery po-rt formed in the bracket 30 when the grate 36 is in the initial position. This port is controlled by. means of a dam-per 69 andthe damper is in turn controlled from the front of the furnace by means of a system of links and rods including the rod 70.

The operation of the Stoker is as follows:

The motor 47 oscillates the shaft 38. which v in turn imparts reciprocatory motion tothe plungers 11- and the moving grate ba'rs'12. The plungers 11 force fuel into the retort lOand through the reto-rt .onto the moving and stationary grates 12 and 12. The cooperation of the plungers 11 and the mov ltd chamber 25 and which, together with .the twyers 67, deliver air to the fuel contained on the grate 36 and ensure jtliorough confbustion of the fuel before theash and elink-- ers are discharged into the'ash pit. The damper 69 makes it possible to blast the fuel contained on the grate 36 immediately prior to the dumping operation. The dump grate may be adjusted so that it will periodically oscillate without opening sufficiently to discharge refuse material into the ash pit, or it may be adjusted so that it will not only break up the clinkers and prevent arching, but will also periodically discharge into the ash pit. In wide furnaces one or more shafts 38 will be employed, and the operating mechanism of the dump grate may be di-.\ vided so that a half, ra fourth, etc. of the dump grate 36 is operated from one shaft 38.

While I have described and illustrated but one embodiment of my invention, it will be apparent to those skilled in the art that various changes, modifications, additions 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.

What I claim is:

1. In combination in a stoker, a dumpV grate mechanism comprising a pivoted dump grate, and power actuated means for swinging said dump grate first upwardly above the normal closed position, and for then dro-pping the grate below the normal closed position during the dumping operation.

2. In combination in a stoker, a pivotally mounted dump grate having its free edge in close proximity to the bridge wall of the stoker, and power actuated means for swingingv the free edge of the dump grate first upwardly above the normal closed-position and then downwardly below the normal closed position during the dumping operation.

/ 3. In combination in/a stoker, a dump grate pivoted so theta/'major portion of its surface may be moved above or below the normal closed vrvposition of the grate, and

means for first' swinging the major portion of the grate above the normal closed position thereof and then drop-ping the major portion of the grate below the normal closed position during the dumping operation.

4. In combination in a stoker, a dump grate pivoted adjacent one edge thereof so that substantially its entire surface may be swung above or below. the normal closed position of the grate, and means for first swinging the grate above the normal closed position to agitate the fuel there above and then swinging the grate to open position below the normal closed position thereof during the dumping operation.

5. In combination in astoker, a fuel feeding plunger for forcing fuel into the furnace, movable fuel supporting elements for moving the fuel toward the rear of the furnace, a pivotally mounted dump grate, power actuated means for actuating said plunger, said members, and said dumpv grate, means for positively connecting the power actuated means with the dump grate during certain portions of the cycle of movement of the power actuated means,and means for adjusting the period of positive connection of the power means with the dump grate including' a stop for the dump grate when the positive connection is released.

6. In combination in a stoker, a fuel feeding` plunger, power actuated fuel lsupporting members, a pivotally mounted dump grate and power actuated means for actuating said plunger and said fuel supporting members, and for swinging said dump grate first upwardly from the normal closed position and then downwardly below the normal closed position during the dumping operation, and adjustable means for controlling the operation of said dump grate.`

7. In combination in a stoker, fuel feeding means, fuel supporting elements receiving the fuel delivered by said fuel feeding means, a pivotally mounted dump grate,

` power actuated means for actuating said fuel feeding means, means'actuated by said power actuated means for first swinging said grate upwardly above the normal closed position, and then downwardly below the norl al closed position into open dumping position, during the; dumping operation, and manually adjustable means for controlling the operation of the said last mentioned means.

8. A refuse discharge mechanism foi' furnaces comprising a dump grate,a power actuated periodicallyy reciprocating member, a casing surrounding said member, dogs mounted on the casing for engaging the, member, means actuated by the casing foi` actuating said grate, a sleeve movable to different )ositions along tli'e casing for engaging sai dogs and for thereby disconnecting the member from the casing and means for adjusting the position of the sleeve so as to vary the amount of motion transmitted to the said grate by -said casing,

ing saidgrate, a rack for actuating said gear,

a casing for actuating said rack, a reciproeating member, means carried by the casing for engaging themember, adjustable means for engaging said casing-carried means and for disconnecting the casing from said member.

10, VIn combination in a stoker, a pivotally mounted dump grate, a' rotatable gear, a link between said gear and said grate so lo.+ cated -with reference to the gear and the grate thatthe grate is swung upwardly during the first motion of the gear, a rack for actuatin the gear, a uniformly reciprocating mem er, means for engaging said member and for thereby actuating said rack, and adjustable' means for controlling the engagement between the said last motion and means of said member.'

11. In an underfeed stoker, a retortto which fuel is fed below the surface of tne fuel contained therein, grate bars located in parallel relation and forming the rear wall of saidretort, mea-ns for reciprocating certain of said grate bars and an apron operatively connected to the movable grate bars for breaking up the fuel entering theretort.

12. In an underfeed. furnace, a retort, a.

plunger for forcing said fuel into said retort, movable grate bars for receiving fuel discharged from said retort and means actuated by said grate bars and located within said retort for preventing packing of the move toward the said plunger for agitatin fuel entering the retort.

13. `In an underfeed furnace, a retort exi tending across the front wall ofthe furnace,

grate bars located in parallel relation and extending from said retort rearwardly,

means for reciprocating some of said grate -ba-rs and means actuated by said moving bars and located within said retort for agitating the fuel entering the retort.

, 14. In an underfeed furnace, a retort, rearwardly extending longitudinal moi/able fuel supporting grate bars for receiving fuel from said retort, a reciprocating plunger for forcing the fuel into the retort below the surface of the fuel contained therein and means actuated by said moving grate bars projecting into the retort and adapted to the fuel and preventing choking in the fue delivery passage through which fuel is forced into the retort by the plunger.

15. In combination in a stoker, a retort eX- tending along the front wall of the stoker, plungers for forcing fuel into the retort below the surface of the fuel contained-therein. grate bars located in parallel relation and extending' from the retort rearwardly, a. fuel ,agitating member on which the ends of the grate bars are mounted, a dump grate located adjacent to said member, and means for actuating said plungers, said grate bars and said dump grate.

16. VIn combination in an underfeed Stoker, a retort extending along the front wall of the Stoker, grate bars located in parallel relation' and extending from the retort rear- Wardly, a movable air delivering member supporting the rear ends of the grate bars, means for transmitting reciprocatory motion to certain of said grate bars, and means located within the retort and actuated by the moving grate bars for breaking upfthe fuel entering the retort. f 1 A 17. In an underfeed stoker, a retort, movable grate bars for receiving fuel from said retort, a movable fuel agitating and impelling member on which one end of each grate bar is mounted, a dump grate mechanism, located adjacent to said member and means for actuating said grate bars, and for imparting motion through said grate bars to said member.

18. In a Stoker, a plurality of grate bars located in parallel relation and each having an air delivery passage formed therein, and an air box for delivering air to said passages having a movable fuel impelling wall upon which theends 0f said grate bars are mounted and which is adapted to be oscil-` lated by the said bars.

19. In a Stoker, a plurality of moving l grate bars having a movable fuel impelling.

' air delivering member forming a wall of said air box and supporting the end of at leastone grate bar, and a dump grate located adjacent to said member and onto which fuel is moved by the cooperation of said moving grate bars and said member.

20. In a Stoker, a. plurality of moving grate bars having an air delivery passage formed therein, an air box for delivering air under pressure to the passages of said grate bars', a dump grate for receiving fuel discharged from said grate bars, the said air box having a movable member forming a wall of said air box and supporting an end'` of at least one of said` grate bars, for agitatingthe fuel on said dump grate.

21. In combination in a stoker, a pivotally mounted dump grate, actuating mechanisms therefor including a stop for holding said grate in a closed position, and power actuated means for swinging the free end of the grate upwardly from normal closed position and then downwardly below normal position during the dumping operation.

22. lIn combination in a stoker, a pivotally mounted dump grate, an operating lever, a pivot for the lever, a link pivoted to the free end of the lever and operatively connectedb to the grate by a link pivot, means for oscillating. the lever so that the free end' passes through a line cutting the lever pivot and the link pivot, and stop means for limiting the movement of the lever so that it Supportstlie grate in closed position when the free end ofthe lever is at one side of the stoker, a pivotally when the free end ofthe lever is at one 'ing the free swinging end of .said grate and the gear in such a manner that the grate ismoved upward prior to a downward Inove- 10 ment effected by the actuating mechanism.

In testimony whereof, I have hereunto subcribed my name this 29th day of August, 191

vvCHARLES F. MILLER.

Witness C. W. MCGHEE'.

Images