US1406702A - Stoker - Google Patents

Description

J G. H. THACHER, 1R.

1 SIOKER.

APPLICATION FlLED JULY 16,191]- 1,406,702, Patented Feb. 14,1922.

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G. H. THACHER, 1R.

STOKER. v APPLICATION F ILED JULY 16,1917- 1,406,702. Patented Feb. 14, 1922.

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STOKER. v APPLICATION mn my 16, 1917. 1,406,702.

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Patented Feb. 14,1922.

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.Mq Mm/M4 G. H. THACHER, JR

STOKER.

APPLICATION FILED JULY 16,1917.

.s attain rA-TEs PATENT OFFICE.

GEORGE HOWELL TEACHER, JR., OF ALBANY, NEW YORK, ASSIGNOR TO VINCENT GILSON ENGINEERING CO., INC., A CORPORATION OF NEW JERSEY.

ISTOKER.

Specification of Letters Patent. t nte 1;, 192,2,

Application filed July 16, 1917. Serial No. 180,855.

T all 10 71cm 2'25 may concern Be it known that I, GEORGE H. THACHER, J r., a citizen of theUnit-ed States, residing at Albany, in the county of Albany, State of 5 New York, have invented certain new and useful Improvements in Stokers; and I do hereby declare the following'to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to Whichit appertains to'make and use the same.

The present invention relates to mechanical stokers of the general type in which the fuel is supplied automatically to a central l5 magazine from which) it is then fed onto grates having inclined surfaces which are agitated to promote combustion of the fuel and from which the ashes are discharged onto cleaning grates located at the bases of the inclined combustion grates.

It is an object of the present invention to produce a stoker of this general character which shall possess, among others, the following advantageous features of combustion andoperation.

The mechanism is built up of a number of units each complete in itself and capable of being removed for purposes of repair or replacement without disturbing any of the other units. The principal elements-of each unit include a hopper from which the fuel is fed mechanically to a retort or magazine from which it is supplied to combustion grates located on 'each side of the magazine and composed of alternate fixed and movable elements, the latter being mechanically actuated to agitate the fuel and render its combustion more complete. The unit terminates on both sides in cleaning grates so 4 designed that the grates of adjacent units fit together to form cleaning pockets of novel construction, but in the case of the side units the outer cleaning grates terminate against the side walls of the furnaces.

The movable elements of each unit have self-contained adjustments which are arranged so that the elements of one-half of the unit may be adjusted independently of those of the other half, thereby permitting to the fire to be controlled in narrow zones. The fuel retorts or magazines between the grates are comparatively narrow and combustion takes place within them as well as upon the grates, which on account of the narrow retorts, gives a maximum grate surface in each unit. Each retort has its own individual air supply which may be controlled independently of the air supply of the other retorts, and. the same is true of the supply of air to the combustion grates of each unit, which takes place throughout the entire width of the grate.

The combustion grates are built up of alternate fixed and movable elements, the'former being of one pattern and the latter of another pattern. Each pattern may be used interchangeably on either side of the central retort. The cleaning grates are all of the same pattern. The principal elements of the mechanism bearing the fuel bed and therefore exposed may thus be constructed of only three patterns, thereby promoting c'heapness of manufacture and rapidity of assembling the component parts .which is further enhanced by providing interlocking fits toeliminate the necessity of bolting or otherwisesecuring together the various elements of the mechanism.

lVithin the fuel retort or magazine of each unit is placed a feeding mechanism of novel construction for causing the progressive advance of the fuel from an external supply. hopper, through the retort and up over the edges of the combustiongrates.

These, as well as many other features of novelty and advantage, will appear more clearly from a description'of a preferred embodiment of the invention as illustrated in the accompanying drawings, in which Fig.1 is a longitudinal elevation in section along the line 1-1 of Fig. 2;

Fig. 2 is a transverse elevation in section along the line 2-2' of Fig. 1;

Fig. 3 is an'elevation of the front of a portion of a furnace equipped with the invention, with a portion of the feed operating means omitted at the-left end;

Fig. 4 is a sectional elevation of a detail of the invention along-the line 44 of s- Fig. 5 is a similar view along the line 5-5 of Fig. 3;

Fig. 6 is a similar'view along the line 6--6 of Fig. 3;

Fig. 7 is a portion of a longitudinal section along the line 7-7 of Fig. 2;

Fig: 8 is a side elevation of a gratebar of one pattern;

mil

throughout the several views, indicates,

the front wall of the furnace, which may be constructed of firebrick or any other suitable heat resisting material. 21 denotes the rear wall constructed of similar material. The front wall may be built out as shown at 22 to form a floor in front of the furnace.

Beneath the floor is a chamber 23 which is connected to a source of air supply and therefore serves as the main air duct forsupplying air to each section of the furnace through the branch ducts 24 which are in the form of pipes passing through the base of the front wall- The ducts 24 lead into the windbox of each section of the furnace and the supply of air. through these ducts may be controlled by a damper 25 having an operating handle 26 extending through. the front wall of the furnace. Girders 27 extend between the front and rearwalls of the furnace on the sides of each air duct. Each pair of girders is bridged by a plate 28 which forms the bottom of the wind-' box and to which the upper end of the air duct 24 is attached in any convenient manner. Resting upon the girders 27 adjacent the front and rear walls are end supports 29 having the shape shown most clearly in Fig. 2 and formed with inwardly directed flanges 30 which rest upon the bottom plate 28 and hence is supported upon the girders 27. These end supports are also formed with inwardly extending vertical flanges 31 to which are attached plates 32 forming the sides of each windbox. The plates 32 are of comparatii 'el-y heavy construction and are bent at their upper ends to form shelves 33 upon each of which is mounted a bracket 34 having forked extensions within which is placed a shaft 35 extending from front to rean of the furnace. Each shaft 35 serves as a support for a cleaning grate 36, composed .of sections, each of which is of the form shown most clearly in Fig. 2 in cross-section and in Fig. 11 in longitudinal section. As appears from these figures each cleaning grate section has an inner face 37 with its surface curved concentrically about the shaft 35 and of about 90 extent. Formed integrally with the inner face 37 is an outer curved face 38 which is perforated along its upper edge for supplying air to the fuel. Each section of the cleaning grates has webs 39 at its ends and these webs have squared slots which fit over corresponding square portions of the shaft 35, whereby each cleaning grate is attached to this shaft so that it cannot move with respect to the latter, but each grate as a whole may be tipped by rotating the shaft. Each bracket 34 extends from front to rear of the furnace, and its vertical face has slots within which the webs 39 of the cleaning grates fit. This construction insures that all air passing through the cleaning grate shall find its exit through the perforations and not be permitted to pass into the space beneath the "grate. To further aid in connecting the grate sections to each other each one of them is formed at one end with a projection 40 and at the other with a depression 41 so that when they are placed upon the shafts the projection of one fits into the depression of the adjacent one, and so on throughout the entire length of the whole grate, thus looking the sections together. 7

' Beams 42 are arranged in pairs and extend from front to rear of the furnace and are supported upon the end supports 29. These beams serve the double purposeof supporting the grates of the furnace and also supporting the members 48 which are'in the form of inverted channel irons extending through the spaceformed between the beams i The members 43, together with the inside faces of the beams 42, thus form a channel or magazine through which fuel is fed to the grates. At the front of the furnace and opposite each one of the magazines is placed a hopper 47 having communication with the fuel magazine by a casing 48 ex-' tending through the fi'ont wall' of the furnace and having its upper side inclined as shown in Fig. 1. It will be understood that this member 48 may have its sides integral" or separate and connectedtogether by any suitable fastening devices. The bottom of this member may be in the form of a channel member similar to the members 43. The outer face of casing 48 is provided with a rectangular aperture within which a pusher or feeder block 49 is adapted to slide. This pusher may be in the form of a box, to which is connected a lever 50 pivoted at 51 to the side of the member constituting the base of 48, and through which base is cut a slot topermit the lever 50 to extend withg -in the pusher 49. The end of the lever 50 may be connected to the side of the pusher or to a rib extending through .the center thereof by a pin and slot connection as indie cated at 52. a .lVithin the fuelmagazine are .placed a which extends a pin 57 of sufficient-length to fit beneath the edges of the slot whereby the block is held in contact with the base of the fuel magazine upon which it slides. The lower end of each lug 56 is connected to an actuating rod 58 by means of a pin 59. The actuating rod extends adjacent the front wall of the furnace where it is attached to a rectangular connecting rod 60 which passes through an aperture in the front wall of the furnace in position to be mechanically actuated by apparatus which will nowbe described.

This apparatus is shown most clearly in Figs. 3 and 6. The outer end of theconnecting rod 60 has an aperture cut through the same and slots 61 are cut in the portions of 60 on each side of the aperture. A pin 62 passes through the two slots and at its ends is connected to thesides of a curved link 63. lVithin the aperture in the end of the rod is slidably mounted astop 64 which is adapted to be moved to any position of adjustment by a screw 65. The upper end of the link 63 is connected to, a member 66 by a pin 67. The member 66 which is a connecting rod is connected by means of a hub 68 to a crank 69, forming a part of a crank shaft 70 mounted in bearings 71 on the front face of the furnace. Shaft 70 is provided at one end with a pulley 72, over which passes a belt 73 running to a power shaft at the top of the furnace. The member 66 may be attached to the hub 68 by means of a split bearing, the two parts ofwhich are connected together'by bolts ,74. The member or connecting rod 66 has a central vertical slot and in the portions at the sides of this slot are slots 75 through which passes a pin 76 connectingthe' ends of the lever 50 which is forked for this purpose.

- A sliding block 77 serving as a stop to limit the movement of the pin 76 is .mounted within the central slot. of the member 66 and is adapted to be retained in any desired position by an adjusting screw 78.

The'shaft has mounted upon it a cyhndrical cam 80, within the groove of which is a pin 81 extending from a rod82 slidably mounted in bearings 83 projecting from the front face of the furnace. As shown most clearly at the left-hand of Fig. 3, rod 82 is provided at its ends with enlarged portions 84 having side slots 85 and depending members 86 within which is mounted a screw 87 to control the position of a stop 88 mounted in a slot extending through the center of the portion 84. lVithin the slots 85 are pins 90 projecting from cranks 91 attached to shafts 92 which extend through the front wall of the furnace. Within the furnace these shafts 92 are mounted in bearings 93 extending upwardly from the end supports 29. A number of cranks 94: are connected to each shaft 92 within the furnace and to the outer ends of these cranks is connected a bar 95 provided with lugs arranged in pairs to receive the lower edges of the movable grates 96. These movable grates are of the pattern shown in Figs. 8 and 9. Each one comprises a central web having a number of projections 97 extending from the faces of the web along the upper and inner edges thereof and spaced from each other to form a plurality of apertures 98 substantially normal to the edges of the grate and through which air may be admitted to the fuel upon the grate. The grate is formed as at 99 with an angular recess which fits over a corresponding angular face on the upper edge of the bar 42 as shown in Fig. 2.

It is intendedthat the combustion surface are also provided with angular recesses 103 which fit over the upper edges of the beams 42 and thus support the fixed grates upon these beams. To prevent these grates frombeing accidentally lifted from their supports, the upper edges of beams 42 have projections or lugs 104 of a width just sufficient to occupy the space between the ribs of the fixed and movable grates. Pins 105 inserted through the lower corners of the fixed grates engage the'bottoms of the lugs and prevent displacement of these grates. In the normal position of the movable grates 1 the air apertures therein should preferably not register with the air apertures of the fixed grates since otherwise there might be a tendency for fuel to drop into these aper tures, become wedged and block movement of the movable grates For the purpose of producing a partial ro- I tation of the shafts 36 uponwhich the cleaning grates are mounted the shafts are extended through the front of the casing as shown at the center of Fig. 3, and carry upon their outer ends cranks 106, which by means of links 107 are connected to the upper end of a piston rod 108 extending into a cylinder 109 within which the piston 110 may be actuated by steam, compressed air or hydraulic power. For the purpose of removing the ashes dumped out of the cleaning grates a door 111 is provided in a front face of the furnace. A similar door 112 should also be provided to permit-access to the cleaning grates for the purpose of removing any clinkers which may .become lodged thereon as well as to permit access tothe surfaces of the combustion grates.

The operation of the apparatus described above is as follows: The hopper L7 is filled with the fuel which is to be burned in the furnace. The shaft 7 0 being driven by the belt-73 will, through the crank 69 and member 66, cause the ends of the lever 50 and link 63 to be moved inwardly and outwardly. Since lever 50 is connected to the member 66 by a pin and slot connection there will be a certain amount of lost motion between these two members, depending upon the setting of the stop 77 with respect to the slot 75. The

effect of this lost motion will be to cause the pusher 49 to be actuated by a series of impulses or blows, which are most effective in driving the fuel from beneath the'hopper 47 into the front end of the fuel magazine. The character of the motion imparted to the pusher 49 by varying the position of the stop 77 in the member 66. If this stop be brought to the outer end of the member there will be no lost motion during the rotation of'the latter and the pusher 49 will have imparted to it a continuous reciprocating movement. If, on the other hand. the stop 77 is carried to'its other limit of adjustment, the motion of the member 66 will have no effect upon the lever 50 since the slots of the member will simply' nected to the rod by a pin and slot connection the rod will have imparted to it a succession of blows whosecharacteristics will depend on the amount of lost motion permitted by adjustment of the stop 64. If the latter be in contact with that end of the slot adjacent to the pin 62 there will be no lost motion and the rod 60 will be reciprocated continuously. For any other positionof stop 64: there will be an intermission in the movements of the bar 60. The bar 58 which is connected to the bar 60 and the pushers '53 which are mounted in the fuel magazine will have imparted to them movementscorresponding to those of the connecting'bar 60. The reciprocation of the pushers will tend to feed the fuel gradually through the magazine and cause it to rise in the latter and pass over the combustion grates on either side of the magazine.

the lever 50 may be varied by During the operation of the apparatus the air supply will be properly adjusted by the dampers 25 and air will pass through the ducts in the grates to cause the most efficient combustion of the fuel as it passes over the grates. The movable-grates are raised and lowered or. reciprocated by the cranks 94 since the shafts to which these cranks are connected are operated by the rods 92 by virtue of the pins 81 and the cams 80 on the shafts which are driven by the belts 73 from the power shaft. By adjustment of the stops 88 the reciprocation of the movable grate bars may-be continuous or intermittent, as in the case of the fuel feed. The movable grate barsserve to agitate the fuel mass and prevent the formation of clinkers and in general to promote more complete combustion. The character of the motion imparted to these grates may be varied while the apparatus is in use by simply turning the adjustingscrews 87to setthe stops 88 at different positions with respect to the slots within which the pins 90 move. On account of the construction of the grates there will be no danger of their becoming wedged against each other and the air apertures should of course be of such .size that no pieces of fuel can drop in and clog them up. A rising and falling movement is imparted to the movable grate sections by the oscillation of the shafts 92, and this movement because of the inclined upper edges of the grate sections tends to move the fuel toward the cleaning grate, that is toward the trough formed by theconcave faces of the cleaning grates. As the fuel is burning during its movement over the combustion grates, it is waste only that reaches the said trough. As the fuel is'burned the residue gradually accumulates in the pocket formed'by adjacent cleaning grates and the edges of these grates are beveled as shown in Fig. 2, to prevent any clinkers from becoming caught between the opposite'sections of the grate. Whenever it is necessary to remove the ashes from the cleaning grates the latter are dumped by actuation of the piston 110, which will, through the cranks 106 and shafts 35, swing the grates into the dumping position. When in this position the portions 37 of the dumping grates will fill up the space between adjacent combustion grates and prevent the escape of any partially consumed fuel which may pass off, of the combustion grates at the time when the cleaning grates are in their discharging position. Preferably the cleaning grates should be formed so that the portions 37 outweigh the portions on the other side of the shaft so that. the'grat-es tend to assume the normal working position.

The entire apparatus is in the form" of units, any one of which may be removed without disturbing the others, each unit comprising a windbox, the fuel magazine above the latter, and a series of fixed and movable combustion grates and cleaning rates on each side of the fuel magazine. in each unit the movement of the fuel grates on one side of the magazine may be ad justed independently of the movement on the other side of the magazine, thus permiting the fire to be controlled incomparatively narrow zones. The fuel feed mechanism of each of the units may be controlled independently of the other units and further- .more the pushers 49 which give the fuel its initial feed into the magazines may be ad justed independently of the pushers which cause the fuel to travel through the magazine. Another feature of advantage in the present construction lies in the fact that all of the cleaning grates are made of the same pattern and the movable elements of the combustion grates are also made of the same pattern and it is not necessary to provide a left and right-hand pattern for use on the'two sides of the fuel magazine. The same is also true of the fixed grates and'of the cleaninggrates, it being only necessary to take care that cleaning grates having their meeting edges properly beveled to overlap be used.

It will be understood that various changes may be made in the details of the invention without imparting from the principle there- I claim:

'1. A stoking unit for furnaces, comprising a fuel retort,-means for feeding fuel into the retort, means slidably mounted within the retort for conveying fuel through the retort. means for actuating the feeding means and the conveying means, said actuating means being constructed to permit independent control of the movements. of the feeding means and the conveying means, and combustion grates 'on each side of the retort.

2. A stoking unit for furnaces, comprising a fuel retort, means for feeding fuel into the retort, means slidably'mounted within the retort for conveying fuel through the retort, means for actuating the feeding means and the conveying means, said actuating means "being constructed to permit independent control of the movements of the feeding means and the conveying means, fixed and movable-combustion grates on each side of the retort and cleaning grates located at the outer edges of the combustion grates.

3. In a stoking unit for furnaces, the combination of a fuel retort, a supply hopper communicating with the retort, means for feeding fuel from the hopper into the retort, means for reciprocating the feeding means, means slidably mounted within the retort for conveying fuel therethrough, means for reciprocating the conveying means, means for actuating both reciprocating means, and means associated with the actuating means whereby the motion imparted to the feeding means and conveying means may be independently controlled.

it. In a stoking device for furnaces, the combination of a fuel supply retort, .a hopper communicating with the retort, a reciprocating pusher for feeding fuel from the hopper into the retort, means for actuating the pusher, a plurality of members slidably mounted upon the base of the retort and formed with inclined faces toward the front of the furnace and substantially vertical faces toward the rear of the furnace, means connecting all of said members in fixed relation, means for actuating said connecting means, andmeans whereby the actuating means for the pusher and the actuating means for'the members may be driven from a source of power, said lastenamed means"being constructed to permit the motion imparted to the pusher and to the members to be independently controlled. 5. In a stoking unit for furnaces, the com bination-of a fuel supply retort, a hopper communicating with the forward end of the retort, a pusher for feeding fuel from the hopper into the retort, a lever for actuating the pusher, a plurality of members slidably mounted within the retort, a rod connecting said members, a driving shaft, a crank on the shaft, a slotted member connecting the end of the crank with one end of the lever, an adjustable stop associated with the slotted member whereby lost motion between this member and the lever may be controlled, a link connected to theend of the slotted member, a slotted rodconnecting the link and the first-named rod, and a stop associated with the slotted rod whereby lost motion between this rod and the link may be controlled.

. 6; In stoking unit for furnaces, the combination of a supporting bar extending through the unit, a series of alternate fixed and movable combustion grates mounted upon the upper edge of the supporting-bar, each of said grate's being formed with a central web and a plurality of projections extending therefrom adjacent the upper and inner edges of the Web, the supporting bars being formed with projecting lugs adapted to fit between the webs of adjacent grates, means attached to the fixed grates and coacting with the lugs on the supporting bar to retain the fixed grates in place upon the bar, and means associated with the movable grates of the series for raising and lowering the same. i

7 A stoking unit for furnaces, comprising a fuel retort, fixed and movable combustion grates on each side of the retort said grates having curved outer edges and cleaning grates mounted at the s des of said com III bustion grates, remote from the retort, each of said cleaning grates being formed with an inner curved face adjacent the curved outer edges of the combustion grates and an outer curved face upon which the materialdischarged from the combustiongrates 1s collected, and means for reciprocating the cleaning grates to discharge material from the outer curved face thereof while main taining a portion of the inner curved face thereof in engagement with the outer edges of the combustion grates.

8. A stoking unlt for furnaces, comprising a fuel supply retort, means: for feeding fuel into the retort, means for feeding fuel through the retort, a shaft, means connecting each of the said feeding means to said

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