US1251146A - Means for promoting combustion of fuel. - Google Patents

Description

G. P. WARD.

MEANS'FOR PROMOTING COMBUSTIONOF FUEL. APPLlcATloN FILED ocT. I6. |916.

Patented Deo. 25.1917.

3 SHEETS-SHEET I.

G. P. WARD. MEANS FOR PROMOTINQ COMBUSTION 0F FUEL.

APPucATloN FILED ocr. 16. |916.

1,251,146. mma Dec. 25,191zi 3 SHEETS-SHEET 2.

G. P. WARD. MEANS FOR FROMOTING COMBUSUON 0F FUEL. 'APPLICATION FILED OCT-AIG., |916- '1,251,-146. N Patented Dee. 25,1912.

. gg I A 6 f/f STATES PATENT OFFICE.

GEORGE P. WARD, 0F CHICAGO, ILLINOIS, ASSIG-NOR 0F ONE-HALF-TO CHESTER L. BUFFINVGTON, OF LA GRANGE, ILLINOIS.

MEANS FOR PROMOTING COMBUSTION OF FUEL.

Specification of Letters Patent.

Patented Dec. 25, 1917.

Appli-Gatien mea october 1e, 191s. serial No. 125,782.

Combustion of Fuel, of which the followingA is a specification.

My invention relates to a method of improving and promoting the combustion of fuel and especially coal screenings, or other more or less finely divided particles of fuel,

and to structures for carrying my invention into effect.

Some of the general objects of my invention are to increase the capacity of furnaces of given dimensions by the production of more rapid and edective consumption of the fuel; varying the speed of the fuel on the grate as the fuel passes through the furnace, and condensing the fuel bed as the volume of the more or lem solid combustible material therein is decreased by distillation and combustion, thereby maintaining the particles thereof compacted, to a degree, to prevent excessive quantities of air fron. passing through the fuel bed, at all times during its progress.

Other and further objects of my invention will become readily apparent to persons skilled in the art, from a consideration of the following description when taken in conjunction with the drawings. wherein Figure 1 is a sectional elevation of my improved furnace and Stoker, as applied to aA water tube boiler, by means of which my improved method of promoting combustion may be carried into effect.

Fig. 2 is a transverse section, taken on line 2 2 of Fig. l.

Fig. 3 is a front elevation ofthe Stoker, with parts broken away, showing other parts in section.

Fig. 4 is an enlarged broken away, longitudinal section through one of the coalmoving screw-threaded shafts or grate members.

Fig. 5 is a transverse section, taken on line 5 5 of Fig. 4. y

Fig. 6 is a transverse section, taken on line 6 6 of Fig. 4.

Fig. 7 is a modification.

In all the views the `same reference characters are employed to indicate similar parts. In the process of combustion of coalor other similar fuel, as it is fed forward into a furnace, on the well known chain grate stoker, for example, the fuel is delivered from a hopper or other suitable source of supply, upon the front portion of the inmoving grate, in a mass which uniformly covers the grate to a depth of several inches. Through this mass, or bed of coal, suficient air will pass from below to properly meet the requirements of combustion. As the coal, in this example,'is fed into the furnace, it first undergoes a coking process, the oceluded gases therefrom being ignited and burned as they are drawn over the incandescing bed toward the point of greatest combustion, near the rear of the furnace. The evolved gases have caused a reduction in volume of the more solid fuel matter, leaving more'a'nd larger voids which will admit a greater and excessive supply of air, for combustion of the resulting coke. As combustion proceeds, in the progressively moving fuel, larger voids are left, as the volume of solid matter decreases, until the excess of air thus admitted, as a result of the changed condition of the fuel, is so great as to produce a chilling effect to the eiliciency detriment of the stoker.

In the chosen embodiment of my improved stoker, the fuel is fed forward thereon into the furnace at a progressively decreasing speed by means that condenses or compacts the deposit and maintains the bed of solid fuel in substantially uniform density, or at any desired variation therefrom, as best adapted for the coal being consumed, whereby to admit only the necessary air, in quantities best adapted for complete combustion, at all the stages in the progress of the coal on the grate.

In the embodiment which I- have chosen for the purpose of disclosing my invention 10 and 10 are the furnace side walls or parts of the boiler setting for the water tube bilerl 11 in connection with which it is shown. l2 is the front wall of the' furnace, which contains on its surface, which confronts the fire, a veneer or coating 14 of ire brick, or the like, which is more or less refractory to the intense heat produced in the furnace. 13 is the front end of the boiler. 15 is a wall at the rear end of the furnace, having a refractory coating 16 over that portion which overlies or approaches nearest to the Stoker grate.

A baffle roof 17, supported by the lower row of water tubes 18, constricts the passage way between the said plate and the wall 12 to provide a throat for the passage of the hot products of combustion arising from the furnace.

Channel beams 19-19 and 20-20- eX- tend the full length of the furnace to support the wall and the refractory projections 21-21 and to support the metallic structure of the furnace. These. channel beams are preferably secured together, back to back, so that the lower beam has its anges projecting outwardly while the inner one has its flanges projecting inwardly forbetter engagement with the masonry and metal parts of the structure. These beams are downwardly inclined from a true horizontal lane, corresponding with the operative surace of the furnace grate shown in Fig. l.

'Io the respective beams 19-19 are con-A nected spaced-apart furnace structure cross beams that extend transversely across the furnace and which are indicated by the designating numerals 22 to 27 inclusive. These beams afford support for the rotary grate bar members to which reference will hereinafter be more particularly made.

The fuel supporting grate structure isf comprised of a series of rotatable, composite, screw threaded shafts of which there are two series, 30 and 31, alternately disposed. One of the series is rotated in clockwise direction, the other series is rotated in the opposite or anti-clockwise direction. Each rotary shaft, of the grate structure, is composed of a plurality of worm or screw threaded sections. In the structure shown, there are five worm sections, of gradually decreasing pitch, that is to say, the worm section 32 has a greater pitch than the adjacent section 33 and will move the fuel bed farther for each revolution of the grate shaft, and in like manner the section 33 has a greater pitch than the section 34, and the pitch of the section 35 is greater than that of the section 36. These worm sections are hollow and are secured together at their ends upon rotatable thimbles 37, provided with notches 38, that engage lugs 39 on each of the worm sections. The threads of these Y sections, on adjacent shafts, are reversed, that is to say, the threads of all of the sections on one shaft will be right handed while those on the shaft adjacent will be Y left handed, so that the threads ofone secshown in Fig. 5. By this means there will be no axial movement of any worms when the shafts are coincidentally rotated in opposite directions. In constructing the grate it is best to permit some material space be tween the parallel worm sections, of adja cent shafts, in order to'provide air spaces through which air may pass, into the bed of superposed fuel from the air chamber below.

The respective connecting sleeves 37 are supported upon the cross beams 22 to 27 inclusive, so as to permit easy rotation of the composite screw shafts. They are held in place on the respective beams by brackets 40 securedto the beams, as by screws 41.

A supplementary cross beam or plate 42 is secured to the channel beams 19-19 at its respective ends, and provides'a bearing for each of the parallel rotatable fuel-moving shafts 30 and 31.

All elongated sleeve 43 passes through the bearing afforded by the beam 22, and through the bearing provided by the beam 4 2, andlis connected to the first section 32 of the rotating threaded shaftgrate members. Each of these velongated sleeves 43. carries a geared pinion. 44 which is secured to its respective composite shafts and is of such size as to inter-mesh with a similar pinion carried by the adjacent shaft, as shown in Fig. 3. Certain of the sleeves 43 also carry a worm-wheel 45 that meshes with and is -driven by a worm 46 which may be carried upon a driving shaft 47. If a worm wheel and worm be used for each composite shaft the use of the intermediate pinions 44 may be dispensed with, but it is evident that a less number of worms and worm wheels may be employed when the intermeshing pinions are used. For instance, a worm and Worm wheel for every alternative shaft would be quite sufiicient and the geared pinions could be relied upon' for the purpose of transmitting power from one composite shaft to the other. The shaft 47 is supported upon 'brackets 48,'that are placed, at suitable intervals,upon the beam 42. The shaft 47 may be rotated by any suitable means, such asa small steam engine. electric motor,

where two of the shafts are located at higher altitudes than those composing the major portion of the grate, an intermediate gear wheel 49 may be employed for transmitting the motion to the geared pinion 50, as the pinion 51 and the shaft upon which it is located is not rotated by a worm and gear drive, as are the remaining composite shafts of the series.

In Order to prevent the rotary shafts from becoming warped by the effect of the intense heat to which they are each subjected, and thereby bein'r distorted out of alinement, so that it would be dicult to rotate them, I

v\or the like. At the ends of the structure 42,

cool these grate members by circulation therethrough of a cooling medium throughout their length. To this end the last coupling sleeve 37 in the series, of each shaft is closed at its end, as at 52, and I extend a pipe, or tube 53, into each of the composite shafts to a point near the closed end 52 of the sleeve 37', as clearly shown in Fig. 7. A circulating cooling medium is passed 1o through the interior plpe 53 until it reaches a. point near the end of the structure Where it passes out into the annular space provided by the interior of the .composite section to 36 inclusive, and through the coupling sleeves 37. The circulating medium may be water, in which event, it is heated by the heat extracted from the grate members by passing through these fuel feeding shafts constituting the grate of the structure, and 2 its temperature being raised to a considerable extent by this means, it may be pumped into a heater and subsequently passed into the boiler, thereby conserving the heat that is taken away from the grate and adding` efficiency to the service. In the particular exemplication there is no means shown for carrying the water away after it passes out through the elongated tubes 43 in the end of each of the rotary shafts, but any sort of a trough or conduitmay be employed for the purpose. In-the eve-nt that air be used for the purpose of cooling the grate members, such a conduit -will be unnecessary, as the heated air will escape from the front end of the structure into the surrounding atmosphere.

For introducing the cooling fluid medium into the tube 53 I provide a header and branch connections 56 therefrom into the respective tubes 53.

Pipes 57 communicate with a. suitable source of air supply and are connected with the head 55. There is one shown at each end, for securing a more equable. distribution of thecooling medium, each of Which is controlled by a valve 58. The pipes 57 are connected to a breeching or head 59, which is at all times filled with air, under pressure, at a few ounces, or to Whatever extent is necessary or desirable for producing the required forced or blast draft that may be employed in connection with my system. The breeching 59 communicates with a closed casing 60 by a pipe 61, of which there is preferably one at each side of the furnace. The casing 60 is located below the furnace and communicates with a chamber 62 included Within a closed casing 63. through regulable dampers or valves G4, 65, G6 and 67. The chamber 62 71, each sub-chamber being provided with a corresponding regulable air inlet. These chambers are divided by plates 72, 73, 74, 75 and 76, there beinga plate immediately 6a below each of the cross beams 23 to 27 inis divided into sub-chambers 68, 69, and

elusive, and there being one sub-chamber for Veach Worm section of the rotatable grate members. v

'lhe base walls of the casing 63 are inclined, so as to cause any siftings or ashes that may fall from the grate, to gravitate toward the transverse center of the casing. The inclined walls of the casing 63 are 'connected in the substantial transverse center of the casing by a pipe 77 having independent ports 78 into each of the sub-chambers G8 to 7l, inclusive, as shown in Fig. l. Another pipe 7 9 fits closely in the pipe 77 and may be rotated therein, by means of a crank arm 80. The pipe 79 is provided with circumt'erenti-all \1 spaced-apart ports 81 that are adapted to register with the respective ports in the sub-chambers (58 tovl7l, respectively, with the (,)pening 78 provided in the outer or larger pipe.. The ports 81 are `not in the same radial or longitudinal planes so that the pipe 79 may be rotated to different degrees to bring either of the ports 81 into register with the respective port 78 in either of the chambers 68 to 7l', respectively. The pipe 79 is provided with one long port, however, 4

which is of sutieient linear extent to include registration with all of the ports 78., in all of the. snb-chamlwrs 68 to 71,'so that when the pipe 79 is turned so as to bring the long port into register with the ports of the respective sub-chambers, communication is thereby made between all of the sub-chambers and the interior of the pipe 79. The pipe 79 enters the three "ay valve fitting 82 containing a three-way valve 83, and comunicating with the vertically extending pipe 8-l, which, near the topv end, is bent forwardly, as at 85. By operation of the threeway valve, the pipe 79 may communicatewith a pipe 86 that is inconnection with an ash receiving receptacle outside of the furnace.

A chamber 88 is provided between the plate 72 and the plate 89 for communication with the space 90 immediately under the segments 32 of the rotatable grate members. A plate 91 is placed under the segments 32 for movement of the siftings from under the segments into the chamber 88. The pipe 79 also has ports communicating with the chamber 88 substantially as here-l tofore described with reference to the larger chambers. The pipe 79 may be rotated,` by means of a crank arm 80, a connecting mechanism 92 and the lever 93.

94 is a beamsubstantially on a level with the' floor surface of the boiler roomA and which carries brackets and 96 for support of the shaft 97 that is rotatable by the lever 93 in the act of rotating the valve pipe 79. lEach of the air-admitting registers, 64 to 67 inclusive, is carried upon an individual shaft 9H, which extends transversely through the respective chambers G8 to 71 and carries on one end a register disk 99 having openings, or ports corresponding with the ports made in the wall of the casing 63 and it carries on the other end a compression spring 100 held in place by a nut 101 in order to hold the rotatable register or valve disk 99 in close and intimate contact with the vertical walls o f the casing. j

Secured to each of the shafts 98 is an arm 103, for the purpose of rotating the regisj ter valve 99. This arm is connected to-a rod 104 which extends forwardly and is connected to a vbell crank lever 105. The lever is providedwith a hand piece 106 and a latch 107 that is spring pressed, as by a spring 108, in contact with a ratchet quadrant 109 so as to hold the lever in adjusted position for the purpose of opening and closing the respective registers to the extent desired. Secured to the cross beams 22 and 23 are bearing brackets 109 and an intermediately disposed bracket 110. These brackets support the transversely extending shaft 111. Each of the levers 105 is loose on the shaft 111, the segments 109 being secured thereto, as by screws orbolts 112, except the segment 113, which is a master segment, and is fixed to the bracket 110, as at 114, and a lever 113, of this segment is secured to the shaft 111, as at 115. Now from the foregoing description it is manifest that the amount of air-passing from the chamber GO'into any one of the sub-chambers 68 to 71 inclusive, may be independently regulated, by the dampers or registers heretofore described, by the manipulation of the respective hand lever 106. After each of the registers 64 to 67 inclusive have been independently set to permit the proportionate quantity of air to pass into the sub-chambers 68 to 71 inclusive, as desired, ,the entirenumber of registers may be simultaneously moved by manipulation of the master 'hand lever 1138*, with reference to the fixed segment 113, whereby the shaft 111, with all of the segments of the 109 class fixed thereto, is rotated correspondingly to move all of the dampers to the extent desired. By this means the amount of air entering any one of the subchambers may be independently lregulated and the quantity necessary or required for them collectively may be varied or regulated by the master lever.

A hopper 120 extends vacross the front of the furnace and is connected with any suitable source of fuel supply. It is provided with an adjustable door 121, supported by a chain 123, upon a segment 124, which turns onthe axis of a shaft 125,

` which also extends across the front of the furnace, and which may be rotated to raise the door 121 to the extent desired to regulate the thickness of the-deposit or bed of coal emplaced upon the rotatablemembers diately below and parallel with the screw'- threaded segments of the grate in the re.- spective sub-chambers. This plate is perforated, as at 127, to permit air, to pass from the respective sub-chamber to the grate members, necessary for supplying oxygen to the burning fuel deposited thereon. The plates are intended to support any loose or iinelydivided coal, or other fuel that may pass dow-n between the 4adjacent screw threaded members and is adapted to hold such coal, or oth-er finely divided fuel, in close proximity with the screw members, so that in the rotation of the screw threaded members the coal, or such fue] as may rest upon the sifting plate 126, will be moved forwardly on the plate by means of the threaded screw and pushed up through the aperture 128, which isprovided by making the screw membershorter than'is shown in the structure illustrated in Fig'. l. By this means the siftings that rest upon the plate 126, will, by the operation of the screw,`be forced up through the aperture 128 into or above the original altitude and be carried on by the next adjacent screw threaded segment, of they rotating grate member to be consumed in its futher progress.

The operation of the device, brieiy, is as follows: The parallel screw threaded grate members being rotated in opposite directions. The deposit of coal on the first segment 32 of the grate members is regulated by they height at which the door 121 is raised above the general surface of the grate structure. The coal, or other similar fuel` is moved lforwardly by 'the threads upon the rotative grate members and as it passes into the furnace begins to coke. By the time the bed of fuel has been thus moved by the rotation of, and along the screw thread- .T/3f members, 30-31, are constantly rotated by the means heretofore described, adjacenty ed members, from the segment 32 to the segment 33, the volume or quantity of-solid matter has, to some extent, been decreased by the coking process. The screw threaded members'33 are of less pitch thank the thread-4 ed members 32 and therefore the bed of coal will be passed along by these members at a relatively slower speed and therefore the particles of the bed will be compacted by the difference in speed of the two members, closing up the excessive air spaces between the particles of fuel resulting from the decrease in volume, due to combustion. When the bed has reached the segments 34, which are of less pitch than the segments 33, the progress of the coal will be at a further reduced speed-rate, and further compression or compacting of the fuel will be etfectuated by the difference in the pitch of the segments 33 and 34, again compensating for the loss of solid matter, due to the effect of combustion. This action is repeated when the fuel passes on the segments 35 and again repeated when it passes on to the Segments 36. As this time the coal is reduced substantially to ash'or cinders and it is thrown oft' at the final end of the segments 36 into a space at. the rear of the furnace, from which it lnay be conveyed by any suitable means, to a more accessible location. The extent to which the bed may be compacted is determined by the difference in pitch of adjacent screw sections.

It will be observed from the foregoing description that the progress of the coal through the furnace is' constantly undergoing` a varying speed rate, being moved slower, substantially in proportion as they members rotatable 1n opposite directions, a

solid matter is consumed.`

In the progress of the coal, should `any combustible matter fall through the rotating grate members into the chambers 68, 69, 70 or 71, it will finally reach the port 78, in the outer pipe in the casing 63, and when the inner pipe 7 9 is rotated, so as to cause the valve therein to register with the restricted port the combustible material will pass through the inner pipe 79 through thel three y way valve 8O and through the vertical inturned pipe 84 and be blown yby the air pressure, which is within the respective chambers 68 and 71 inclusive, into-the incandescing coal or the hot gases therefrom, Within the furnace.

The amount of combustible material will decrease progressively from the chamber 68 to the chamber 71. The chamber 71 will contain largely ash and when it is desired to remove the ash from the chamber 71, the three-way valve may be rotated, so that it will communicate with the pipe 86, then the pipe 79 should be rotated so that the valve 81 will communicate with the valve 78 of the chamber 71, whereby the air pressure, within the chamber 71, will cause the ash to be blown out into a space beyond the furnace, from which it may be subsequently conveyed, by any suitable means.

While I have hereinshown a single embodiment of my invention for the purpose of clear disclosure it is manifest that many changes in the general arrangement, disposition and configuration of the parts may be' made within the scope and intendment of the appended claims.

Having describedmy invention, what I claim is 1. In a furnace, a series of parallel, rotatable grade-members, bearing fuel-movingworms, the pitch whereof progressively de-` creases toward the rear of the furnace.

2. In a furnace, a series of parallel, rotatable grate-members, each bearing, respec tively, rightand left hand intermeshing worm-members, the pitch of which decreases progressively with the movement of the fuel thereon.

3. In a furnace, a series of parallel, rotatable, hollow `Agrate-members bearing, respectively, right and left hand, intermeshing worm members, the pitch of which decreases progressively with the movement of the fuel thereon and means to pass a cooling medium through said members.

4. In a furnace, a series of parallel, ro-

tatable. hollow grate-members bearing, re-

series of alternate members each composed of rlght-hand worin-sections intermeshmg with a series composed of left-hand Wormsections, .said sections decreasing in pitch,

progressively from front to rear of the grateand connections lbetween said grate -members, whc-feby to rotate them.

6. In a furnace, a series of parallel, rota- "table grate members, each composed of worin-sections of varying pitch arranged with sections of greatest pitch to receive the fuel and progressively decreasing in pitch toward the rear end of the grate, .adjacent grate members being rotatable in opposite direct-ions and lbearing right and left hand worm-sections, respectively; an air-proof casing under each section and regulable means for admitting .air under pressure into said sections.

7 In a furnace, a series of parallel, rotatable grate members, each composed of worm-sections of varying pitch arranged vwith sections of greatest pitch to receive the fuel and progressively decreasing in pitch toward the rear end of the grate, adjacent grate 'members 'being `rotatable in opposite direction and bearing right and left hand worm-sections, respectively, an air-proof casing under each section and independently y regulable means for admitting air under pressure into each said casing.

8. In a furnace, a series of parallel, rotatable, hollow grate-members each composed of worm-sections of varying pitch, arranged with sections of greatest pitch to receive the fuel and progressively decreasing in pitch toward the rear end of vthe grate, adjacent grate members being rotatable in opposite directions and bea-ring right and left hand worm-sections, respectively; an air-proof casing under each section; independently regulable means for admitting air under pressure into each said casing; a'pipe extending through each grate member to conhand in the presence of two subscribing Vey a, cooling ymedium under pressure Witnesses. v through each said member to permit the GEORGE P. WARD.

medium to return to the end at which it 5 was introduced and a header for` al1 said In the presence oipipes. FORE BAIN,

In testimony whereof I hereunto set my MARY F. ALLEN.

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