US2380452A - Furnace gbate - Google Patents

Description

Patented July 31, I945 UNITED STATES PATENT OFFICE FURNACE GBA'IE George A. Koiiout, Chicago, 11].

Application May 14, 1942, Serial No. 442,885

7 Claims- (Cl. 110-38) The present invention relates to furnace grates and is particularly directed to a novel grate con-- the fuel effects sifting of the fine particles of fuelthrough the air openings of the grate, thus destroying the efficiency of the grate as a means of carrying the fuel bed. Stationary grates which are provided with fine holes substantially avoid this difilculty because the forced draft upward through .the openings prevents the particles from falling through to an appreciable extent and only those fine particles which fall directly upon an opening have an opportunity to pass through.

The present invention provides aconstruction whereby the shaking of the grate incident to its movement to advance the fuel bed does not cause 'thefuel to'sift through the grate.

In accordance with the present invention a movable grate section is provided of a desired width, this section being made up of a plurality of individual units which may be any desired number that is necessary, that is, to provide the desired length of the grate section. 'Ifhe several sections are supported by a reciprocating member which is in turn supported upon rollers or the like so that it may be easily moved.

In the preferred form of the invention .the

mg drawings. It should be understood, however, that the' drawings and description are illustrative only and-arenot to be taken as limit-' ing the invention except insofar as by the claims.

In the drawings- Fig. 1 is a longitudinal section taken through the fire box of a boiler and through the fuel feeding mechanism including the grates which are the subject matter of the present invention. Only a portion of the boiler is shown since obviously it is limited the details thereof form no part of the present invention Fig. 2 is a vertical section taken substantially on the line 2-2 of Fig. 1;

Fig. 3 is afragmentary plan section taken on theiine I-l ofFig.2; v

Fig. 4 is a fragmentary sectional view taken on the line 4-4 of Fig. 2;

Fig. 5 is a perspective view of'the under sur face of one of the air directing plates that forms a part of the-greate; and

Fig. 6 is a fragmentary sectional view taken substantially on the sameline as Fig. 2 but illustratinga modified wall construction to cooperate with the grate. Y

Referring now in detail to the drawings, the

I present invention is shown as embodied in a grate is an integral part of a fuel trough, one end of which projects from the fumace beneath a hopper that supplies the fuel. Y The other end of the trough projects from the furnace over a receptacle or pit for receiving ashes.

In the preferred form of the invention the hopperis placed to the rear of the'furnace so that the material to be, removed, namely, the ash, is delivered at the front of the furnace. Any suitable means'may be provided for supplying forced draft through the grates. However, the present invention contemplates a novel construction whereby the distribution of air lengthwise of the grate may e controlled. 1 i,

Other and more detailed objects and.advantages of the invention will appear as the description proceeds in accordance with the accompanyfurnace construction which includes a boiler in having a fire box H with an oven fire door at i2 and with a bridge wall at I3. '15. fuel hopper H is placed at the rear of the fire box and is located directly over a reciprocatory fuel feeding trough it. The hopper fits down into the trough but is supported independently thereof by means of oppositely disposedside plates Itand' I]. These side plates extend through the furnace and provide a supporting structure inside the side walls of the furnace, the supporting structure being of such nature that it carries the recipro-' catory trough It as well as afirc' brick assembly that .forms a part of theibase of the combustion chamber.

The trough it comprises two elongated Z- shaped side plates i8 and I8, each platebeing'supported by two rollers such as 20 and 2| illustrated'in' Fig. i. The stationary side plates i6 and II have angle irons 22 and 23 extending inwardly at the bottom edges thereof andthese angle irons carry rails- 24 and 25 for the rollers 20 and 2 I. Two angle irons 28 and 21 are secured to the plates i8 and It by welding Or otherwise, and provide. supports for-an apertured bottom plate 28 that'extends below the trough it throughout the entire distance from the portion of the trough l5 beneath the hopper to the discharge end of the trough. This plate has a section located directly beneath the flre box that is provided with a multiplicity of relatively large openings 23, these openings being staggered so as not to weaken the plate structurally any more than is necessary to provide for passage of air upwardly through it.

The trough i5 is supported upon the plate 23 in spaced relation thereto, a, series of cross bars 30, 3!, 33 and 33 being provided for that purpose. This trough l5 comprises a front section lie that receives the discharge end of the hopper It. This front section is also provided with an extension 34 which has an upwardly extending flange 35 and a depending flange 36. The upwardly extending flange 35 has a roller 31 at the top thereof, which roller is adapted to engage a cam 38 that is mounted on a shaft 33 supported upon suitable arms 40 from the side plates I 5 and I 1. The shaft 33 is rotated by means of a pulley 4i and a, belt 42 upon a drive unit 33 which may be any suitable device such as an electric motor. The lower flange 36 is connected by a spring 44 to a stationary cross piece 45 which is carried by the side plates l6 and II. The cross piece 45 also carries a yielding bumper or stop 46.

. In operation, when the cam 38 is rotated it will gradually move the extension 34 and trough l5 to the left as shown in Fig. 1 until it passes over the roller 31 at which time the trough is freed to move to the right. A spring 44 is under sufilcient tension at this point to move the trough l5 to the .right at a rapid rate. As this occurs, the fuel in the trough I5 is of course advanced to the right. However, when the flange 36 hits the stop 46 there is a sudden deceleration in the movement of the trough i5 and loose fuel in the trough continues to move to the right due to its momentum, thus effecting an advance of fuel in the trough.

From the foregoing explanation it is believed that the general operation of the impact feeding means will be sufflciently clear for the purposes of this application. The impact feeding means itself forms a subject matter of a separate application flied by me of even date herewith and will not be described further.

The trough l 5 includes an intermediate section I5b which is made up of the grates that are the subject matter of the present invention. The trough also includes a discharge section i5c that is adaptedto carry the ash, clinkers, etc. from the grates to a receptacle 41. In order to substantially seal the furnace chamber at the inlet and discharge ends, two floating gates 48 and 43 are provided. The gate 48 is hinged as indicated at 5B and floats on the top of the entering fuel bed. The gate 49 is hinged at 5| and rides on the top of the ash being discharged. Any suitable means may be provided for controlling the operation of these gates so as to enable them to perform their functions as adjustable closures that will follow' the height of the fuel bed and the ash-bed, re-

spectively.

Referring now specifically 'to the grate construction or section i5b of the trough l5, this section comprises a plurality of grate units 52, 53 and 54. The several grate units are duplicates and a the connection between the aprons and the trough itself.

In the bottom of the casting 55 there are spaced air inlet apertures 32, these apertures 82 being arranged in spaced rows that extend langthwise of the trough from one "edge of the grate section to the other edge. The casting 55 also has depending bosses 63 which have embedded therein bolts 64 (see Fig. 2). These bolts extend through the plate 28 and are threaded to receive nuts 65 so that the grates may be securely fastened to the plate 23. Over each row of apertures 62 there is provided a chanelled plate 56 that is secured in place by means of bolts 61 that extend up through the casting 55 from the bottom. The channelled plates 85 have V-shaped channels in the bottom surfaces thereof extending to the side edges of the plates with the outlets of the channels all pointing toward the discharge end of the trough- I5. The channels are so arranged that the outlet ends of the channels in two adjacent plates are.

staggered with respect to each other to avoid the air passing out through one interfering with the air passing out through the opposite one. The

outlet ends are staggered by making one leg or branch of each V-shaped channel substantially longer than the other leg or branch. This construction is illustrated most clearly in Figs. 3 and 5. It will be noted that the V-shaped channels are arranged so that an opening 32 is directly beneath the apex of each V-shaped channel. Thus air under forced draft will pass up through the opening 62 and then rearwardly along both branches of the channels to discharge in the space between adjacent plates.

In operation the grates are given a gradually accelerating motion toward the rear of the furnace and are then suddenly stopped causing the fuel thereon to move rearwardly with respect to the grate. This shaking action does not cause the fine coal to enter or clog the channels in the plates 66. The naturalmovement of the coal particles is in the same direction that the channel outlets point. In addition the air passing through the channels tends to keep them clear. It will be evident from this description that I have provided means to carry out the principal purpose of the invention, namely, an impact grate with means for passing 'air through it to the fuel thereon and means to prevent sifting of the fine v coal through the grate.

' the righthand end as shownin Fig. l is swung down it will open a greater inlet area for supplying The forced air enters the furnace in any suitable fashion; as for example, through an inlet duct 10 shown in Figs. 1 and 2. The air is delivered into a compartment ll formed beneath the grate sections by the interposition of two end walls 12 and I3 and two side walls 14 and 15. The compartment H has therein a series of adjustable bailles 13 and a series of flxed baffles 11. These bafllesare in the form of slanting plates. The several baffles 16 are pivoted on rods 18 that are carried by the side walls 14 and 15. All of the baille plates 15 are connected to individual operating rods 13 so that the baffles can be adjusted to direct different amounts of air to different grate sections. For example, if the baiile 16 at air to the fuel on the front grate section. If more air is needed for any particular grate section than 2,380,452 ried on theside plates l6 and H in such a fashion as to be readily removable. Castings 8| are shaped to provide a. lip portion at 82 and a ledge portion 83. The lip portions 82 extend down beh'ind the plates l8 and I! while the ledge portions 83 extend down inside angle irons 84 that are provided at the top of the side plates l6 and H. The ledge portions 83 are recessed to receive lugs 85 that are formed on the blocks 80. The castings 8| are spaced above the aprons of the grate castings 55 so as to provide additional air spaces 86 for passing air into the furnace and for cooling the castings. At the front and rear wall of the furnace combustion chamber supporting plates 81 and 88 are provided and these supporting plates are protected by refractory blocks '89 and 9B.

In Fig. 6 there is shown a slight modification of the structure whereby the refractory blocks 80 are eliminated. In this construction the casting 8i and the refractory blocks 80 are replaced by apertured castings 9|. These castings have ledge portions 92 that are spaced above the aprons of the grate castings 55 leaving the same air space 8|. The castings 9| however extend upwardly and outwardly from the ledge portions 92 and are provided with several aperture 93, the casting being hollowed out in back.' of the apertures so as to permit air to circulate through them and keep them cool. Depending ribs at the rear of the castings 9| serve to hold them in place on the plates l6 and Il. To further aid in cooling the castings 9| fins 95 are formed therein between the apertures 93.

From the foregoing description it is believed to be evident that I have-provided a grate construction which is of such a nature as to permit air to pass upwardly through it while it prevents sifting of coal downwardly even under the impacts that are necessarily a part of fuel feeding by the impact method.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A furnace grate adapted to have fuel advanced over it'by reciprocatory movement of the grate, comprising a bar having spaced rows of air inlet openings extending upwardly from the bottom of the bar, and cover means on said bar for said rowsof inlet openings providing diverging air passages from each row, which passages extend in the direction of advance of the grate and open upon the top surface of the bar, said cover means comprising plates secured on said bar and having V-shaped grooves in their lower surfaces one le of each groove in a plate extending to one side edge of the plate and the other leg of the groove extending to the opposite side edge of the plate, the apex of each groove overlying one of the openings.

2. A furnace grate bar for furnaces wherein the ,fuel is advanced over the grate by reciprocating the grate, said grate bar having its top surface made up of alternate ridges and valleys and said bar having air inlet passages extending upwardly beneath the ridges to the level of the valley surfaces cf the bar then diagonally outward at substantially the same level through the ridges to the fuel receiving surface of the bar at the level of the adj acent valley surface.

3. A furnace grate bar for furnaces wherein the coal is advanced over the grate by reciprocating the grate, said grate bar having its top surface made up of alternate ridges and valleys and said bar having air inlet passages extending upwardly beneath the ridges to the level of the valley surfaces of the bar then .diagonally outward through the ridges to the coal receiving surface of thebar at the level of the adjacent valley surface, the outlet ends of the passages in a ridge being staggered with respect to the outlet ends of the passages opposite them across the intervening valley.

4. In a progressive feed grate construction for furnaces wherein the fuel is advanced over a substantially horizontally extending grate surface ridges to the side edges of the ridges from said openings, with their outlet ends at the level of said fuel carrying surface, said passages having their outlet ends pointed toward one end of the ridge in which they are located whereby the air discharged through said passages sweeps the fuel carrying surface between the ridges, and tends to move fuel particles thereon toward one end of the grate bar.

5. A non-sifting progressive feed grate construction for furnaces wherein the fuel is advanced over a substantially horizontally extend ing grate surface byreciprocatory shaking ofthe.

grate that tends to sift fine fuel through the grate, said grate construction comprising grate bars, means mounting said bars side by side to form a substantially horizontally extending fuel receiving grate surface movable as a unit, each grate bar having spaced rows of air inlet openings extending upwardly from the bottom of the bar to the level of the lowermost fuel carrying surface, the rows running in the direction of advance of fuel on said grate surface, and each grate bar having ridges over said openings, the ridges being provided with passages extending through the ridges to the side edges of the ridges from said openings, with their outlet ends at the level of the fuel carrying surface, said passages having their outlet ends pointed toward the discharge end of the grate whereby the air discharged through said passages sweeps the fuel carrying surface between the ridges, and tends to move fuel particles thereon toward the discharge'end of the grate.

6. A non-sifting progressive feed grate construction for furnaces wherein the fuel is advanced over a substantially horizontally extending grate surface by reciprocatory shaking of the grate that tends to sift fine fuel through the grate, said grate construction comprising a plurality of castings'secured together into a substantially horizontal continuous fuel receiving trough, the trough having spaced air inlet openings extending upwardly from its lower face to the level of the bottom of the tfough, and ridges over said openings, the openings including passages in said ridgesall running toward the discharge end of thetrough through the ridges with their outlet ends at the level of the bottom of the trough, said passages having all of their outlet ends pointed toward the discharge end of the trough whereby the air discharged through said passages sweeps the bottom of the trough, and tends to move fuel particles thereon toward the discharge end of the trough. 7. A non-sifting progressive feed grate construction for furnaces wherein the fuel is advanced over a substantially horizontally extending grate surface by reciprocatory shaking of the grate that tends to siftflne fuel through the grate, said grate construction comprising a plurality of castings secured together into a substantially horizontal continuous fuel receiving trough, the trough having spaced rows of air inlet openings extending upwardly from its lower face to the level of the bottom of the trough, and ridges over said rows of openings, the ridges having passages therein running from said openings, outwardly and toward the discharge end of the GEORGE A. KOHOUT.

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