US1944332A - Grate bar - Google Patents

Description

Jan. 23, (1934. 1 s, THQMPSQN 1,944,332

GRATE BAR Filed Feb. 17, 1931 Patented Jan. 23, 1934 UNirED STATES GRATE BAR James S. Thompson, New Rochelle, N. Y., assignor, by mesne assignments, to Waugh Equipment Company, New York, N.'Y., a corporation of Maine Application February 17,

6 Claims.

This invention relates to grates of the type used in locomotive fire boxes, boiler furnaces and for other heavy duty purposes and is concerned more particularly with a grate bar adapted for the above uses and suitable for installation either in a stationary grate frame or in a traveling grate.

The grate bar of the invention is so constructed as to have the necessary strength without great weight. In addition the bar has a long life, and should repairs be necessary, they can be made readily with a minimum expense for labor and parts.

To carry out these purposes, the grate bar is made up of a carrier adapted to be mounted in a grate frame or traveling structure, on which are disposed a plurality of independent fuel supporting units. Each unit is secured to the carrier against accidental dislodgment but has a limited freedom of angular movement relative to the carrier. Each unit is in part hollow to lighten it and in the preferred construction, the bottom part of the unit is made of steel plates while the top is of solid cast metal. In order to prevent cracking of the top due to strains resulting from unequal expansion of the top and bottom, the top is made of a plurality of separate parts secured to the bottom but not to each other, so that the difference in expansion between the top and bottom is not cumulativethroughout the length of the top.

For a better understandingof the invention, reference may be had to the accompanying drawing, in which Fig. 1 is a view of a grate bar embodying this invention in transverse section;

Figs. 2 and 3 are sectional views on the lines 2-2 and 3-3 of Fig. 1;

Fig. 4 is a fragmentary side elevational view of the bar shown in Fig. l;

Fig. 5 is a view on the line 5-5 of Fig. 1;

Fig. 6 is a front elevational view of a portion of a modified form of grate bar embodying the invention; and

Figs. 7 and 8 are sectional Views on the lines '7 7 and 8--8, respectively, of Fig. 6.

The grate bar illustrated in Fig. l includes a carrier which is made up of a longitudinal web 10 having a centering ange 1l extending lengthwise thereof along its upper surface, and a strengthening rib 12 extending downward from its under surface. Also extending downwardly from the carrier at an appropriate point is a shaker arm 13. At its ends the carrier is provided with supporting means which may take the form of upstanding arms 14 with projecting trunnions 15 in the case of a bar which is to be mounted in a stationary grate frame.

Mounted on the carrier and extending transversely thereof are fuel-supporting units, each of 1931. Serial No. 516,289

which includes a bottom 16 and a top generally designated 1'7. The bottom is preferably hollow and to give the necessary strength as well as lightness, the bottom may be made up of a pair of steel plates formed with edge flanges 16' along their lateral and bottom edges, these plates being secured together with their flanges in contact, as, for example, by being welded along the flanges. The bottom has an opening along its upper edge and extending into the opening is the fuel-supporting top of the bar which includes a plurality of blocks 18 preferably of cast iron and arranged in a row from one side of the unit to the other with adjacent lugs separated a short distance.

While the top of the unit may have any desired form, I prefer to construct the unit to embody certain features set forth and described in an application for patent filed in the name of Buckley, Serial No. 338,352, filed February 8, 1929, now'Patent No. 1,884,557, October 25, 1932. In accordance with the Buckley invention, the top of the bar is provided with lugs 19 projecting from at least one face thereof, these lugs being spaced apart to denne vertical passages 20 for the upward flow of air to the fuel carried on the unit. Above each lug are fuel-supporting projections 21 separated by air channels 22 and 23the latter channel communicating at its ends with air passages 20. These projections are of tapering cross'- section toward their tops and provide the desired support for the fuel with but a relatively small area at the bottom of the fuel bed in actual contact with the grate itself. Preferably the projections are arranged in` groups of four with two projections of the group extending upwardly from the top of a lug and the other two projections extending upwardly from the main body of the block adjacent the lug.

In the form of fuel-,supporting unit illustrated, each of the plates of which the bottom is made up is shaped to provide projections 24, which serve as continuations of the lugs 19. Also, at the middle of the unit, the two adjacent lugs on the top are not separated to form an air` channel between them and the plates have upward extensions 25 which terminate near the bases of projections 21 above them. This use of the extensions on the plates strengthens the unitat its mid-point.

The plates are formed with a recess 26 in their bottom edge, the shape of which corresponds generally to the cross-sectional shape of the web 10 of the carrier. Preferably the shape of the recess is such that the unit rests on the top surfaces 27 of the web on either side of the iiange 11,

with the walls of the recess out of contactwith the flange. At its lower end, the recess is restricted to provide lugs 28 and the distance between these lugs may be less than the greatest dimension of the web, in which case the units may be lifted clear of the web by a movement at right angles thereto. Preferably the distance between the lugs is slightly less than Ythe 'greatest width of the web, in which event, the arm 14 at the ends of the webs is made narrower than the distance between the lugs, and the web is cut away at its sides adjacent the arms so that the end unit on the carrier may be tilted on an axis at right angles thereto to cause its lugs to clear the edges of the web. The lugs then pass over the sides of the arms so that the unit can be removed from the carrier by a movement in a plane inclined to the top surface of the web. When the distance between the lugs and the units is less than the width of the web, the units `cannot be removed except by a combination of tilting movements, but with either construction tilting of the carrier in dumping or shaking operations causes the units to swing about a point on the carrier as a pivot and one or the other of the lugs 28 lpasses beneath and engages the edge of the web of the carrier and secures the unit rigidly thereto. In producing the units, the bottom plates are first formed of sheet stock and then secured together by welding or in any other suitable rnanner. The bottomv is then placed in a mold of appropriate form and cast iron run into the mold to formthe top. In order to secure the top to the bottom, the bottom is formed with aplurality of openings 29A near the upper edge thereof and in the casting of the top, tongues of metal 30 pass through these openings and thus serve to anchor the top and bottom securely together. Preferablythe top'extends into the bottom for a short distance, the lower edge of the top within the bottom extending down to a line, for example, such as is illustrated at 31'. v Since the bottom is made of steel and the top of cast iron and these two' metals have different rates of expansion,v the unit. would be subjected to strains by reason of this difference in expansion, which might result in crackingvof the top if the latter were inl one piece. While this cracking would not be likely to 'result in parts ofthe topV being freed from the bottom by-reason ofthe manner in which 'they top and the bottom are secured together, this might occur and if a part of the top were freed from the bottom, the unit would have to be discarded. .In order to obviate any difficulty from thisV source, the top is preferably made of a plurality of separate blocks formed by a suitable casting operation, these blocksr lying in a row which extends lengthwise of the bottom with the'adjacent blocks separated by a space indicated at 32. With this arrangement, the total effect of the difference of eXpansion is not cumulative from one end Vof the unit to the other but is so distributed that no cracking of the top is likely to take placev regardless` of the temperature to which the unit is raised.

In the construction illustrated in Fig. 1, the unit is provided with atop which is made up of four' blocks, whilein the construction shown in Fig. 6, there are five such blocks making up the top. Also, in the modified construction, the plates 82 which constitute .the bottom are not formed at their upper ends with projections 24 which serve as continuations of Athe lugs 18 but onv the contrary the tops of the plates32 lie embedded in the blocks which constitutek the top. With either construction, difficulties which might arise from the unequal expansion of the top and bottom are overcome by reason of the subdivision of the top into a plurality of parts` independently secured to the bottom.

I claim: k

1. A grate bar which comprises the combination of a rocking carrier and fuel supporting units mounted' thereon and extending beyond the lateral edges thereof, each unit consisting of a hollow steel bottom member having spaced side Walls providing an open upper end and formed with a recess in its lower edge for reception of the carrier and solid blocks of metal having portions received between said side walls and se-k cured thereto, said blocks being separated along said bottom member by spaces.

2. In a grate bar, a fuel supporting unit havingv a supporting bottom and a fuel engaging top, said top and bottom being made of metals having different rates of expansion, said top being made up of a plurality of solid blocks, each provided 'with spaced lugs on its lateral faces providing vertical air channels, and said bottom being of hollow sheet stock with portions of said blocks received therein and anchored permanently thereto, said bottom being formed with an opening for the reception of a carrier.

3. In a grate bar, a fuel supporting unit comprising a bottom made up of a pair of plates of sheet stock secured together and a top made up of a plurality of blocks of solid metal, each block having a portion Vextending between said plates and permanently secured thereto and each block also having spaced vertical lugs on its side faces and a multiplicity of projections at its top, said lugs partly defining vertical air channels through which air may flow to fuel supported on said projections.

ll. In a grate bar, va fuel supporting unit comprising a hollow bottom of sheet stock having spaced walls, said walls having openings therein and a top subdivided into independent sections, each section having a portion received between said walls, said portion having projections therefrom entering said openings to secure said section permanently to the bottom, each section also having spaced vertical lugs on its side faces partly defining vertical air passages, and also having a plurality of spaced fuel-supporting projections at'its top.

5. A grate bar which comprises the combinatiorr of a rocking carrier and fuel-supporting units mounted thereon and extending beyond the lateral edges thereof, each unit comprising a hol- 1 low bottom member of sheet stock formed with an aperture for the reception of the carrier and a top made up of solid blocks, said bottom member having its walls spaced at its upper end and said blocks having portions lying between said walls and independently secured thereto with said blocks spaced apart. Y

6. A grate bar which comprises the combination of a member consisting of a carrier portion ll() I and supporting means lying at one side of the Zi.

longitudinal axis of Vsaid carrier portion, said means being adapted to permit said portion to swing about said means, and a plurality of fuelsupporting units mounted on said carrier portion, each'unit comprising a hollow sheet metal il..

bottom having an aperture in which said carrier portion is received, and a plurality of hollow blocks, the side walls of the bottom being spaced at the top thereof and each block having one end received between said side walls and permanently anchored thereto, said blocks providing a fuel supporting surface and adjacent blocks being spaced apart.

JAMES S. THOMPSON.

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