US2246715A - Furnace grate - Google Patents

Description

Imie 24, 194i. I Q B BODENE ,246,715

FURNACE GRATE Filed Dec. 6, 1937 Patented June 24, 14941 FURNACE GRATE Charles B. Bodinc, Jersey City, N. J., assig'nor, by direct and mesne assig'nments, of one-half to Percy'E. Landolt, and one-half .to Samuel H. `Wechstein, both of New York,'N.`Y.

Application December 6, 1937, Serial No. 178,393

1 Ulam.

The present invention relates to grates for burning coal and particularly to grates for burning the smaller grades of coal such as buckwheat, rice and the finest sizes, including coke .breeze, without the necessity of employing forced `draft.

It `is well known, as explained .in the patent to Andrew Gaul, Jr., No. 1,851,425, that ordinary grate structures are not adapted to the burning of finer sizes of coal. This is due .to the fact that the spacing between ordinary grate bars is so great that an excessive amount of coal is wasted by falling through the spaces between the bars into the ash pit. If the spacing of the ordinary bars is reduced, the available space for passage of combustion air is reduced to the extent that forced draft is required and if the thickness of the bars is also reduced, warping invariably results rendering the grate useless. Gaul proposed to overcome the disadvantages of prior structures by providing a grate comprised of a plurality of very thin but deep fins having their maximum thickness at the top and spaced to provide a fuel supporting surface in which the thickness of the fins was less than the distance therebetween. This structure resulted in a grate which, due to the large amount of air space compared to metal area, successfully burned small sizes of fuel without forced draft, and was amply cooled by the natural draft of air therethrough.

It is an object of this invention to provide a grate bar unit which embodies certain of the principles of the Gaul grate, and which may be usedwith a number of similar units in making up a grate for burning the finer grades of fuel.

Another object is to provide a grate unit which may be removably mounted on a supporting base, which may be the rocking bar of a grate, together with other similar units to make up a fuel supporting grate.

Another object is to provide an assembled grate bar for burning finer grades of fuel in which any number of the assembled units may be removed or replaced without disturbing the remainder of the |assembly and without removing the rocking bar from the furnace.

Another object is to provide a grate bar unit including a plurality of groups of spaced thin blade members providing a grate in which the blade members are disposed well above the under supporting bar structure and in which the distribution of air to said members is equalized over the entire area of the grate.

A grate constructed according to the invention may be a dumping or a stationary grate. When applied as a dumping grate with a rotation of 90 tions of older types with a minimum of expense for installation and for subsequent replacement in service.

O ther objects and advantages of the invention will become apparent upon reference to the following detailed description of the invention and to the accompanying drawing, wherein Fig. 1 is a semi-diagrammatic view illustrating, generally, a grate assembly embodying theinvention,

Fig. 42 is an enlarged sectional elevational view takensubstantially on the line 2-2 of Fig. 3,

Fig. 3 is a top plan view of a grate bar unit, according to the invention,

Fig. 4 is an end elevational view of the same, and

Eigs. 5 and Sare perspective views of the blade elements.

With more particular reference to the drawing, Flg. 1 illustrates a rocking bar grate Ill embodying the invention. This grate includes an apprcpriate supporting frame including frame members |2 and [3. A plurality of rocking bars 14, |5 and IE are journalled 'at their ends in the frame members |2 and |3. The rocking bars are preferably connected for simultaneous operation by suitable means such as meshing gear wheels l'l, |8 and l9 and the bar |4 may have one end extended and squared as at 20 for engagement by a Shaker handle.

The fuel bed supporting surface is made up of a plurality of grate bar units 2| which are rem-ovably assembled on the rocking bars Ill, 15 and Hi and are sized so that when a proper number thereof is assembled, they completely fill the space enclosed by the frame of the grate.

The units 2| are of similar construction and comprise a pair of parallel spaced upstanding supporting plates, which for convenience will be termed front and rear plates 22 and 23, respectively. The plates 22 and 23 are secured together in spaced relation by sets of tie bars 24, 25 and 28 approximately equidistantly spaced from each other adjacent the upper edges of the plates 22 and 23 and a pair of tie bars 21 between the lower portions of the plates. The tie bars are of equal length and have their ends suitably anchored to the plates to form a rigid unit. The tie bars may be welded, riveted or threaded to the supporting plates.

Each set of tie bars 24, 25 and 26 serves the additional purpose of supporting rows or groups of relatively thin blades or fins 28, 29 and 30 respectively. The blades of each group are uniformly spaced from each other and from the supporting plates 22 and 23 to provide air passages therebetween. The desred spacing is automatically obtained during assembly by means of spacer lugs 3| and 32 that project from the front faces of the blades and supporting plates respectively. The blades are preferably cast from a strong heat resistantmetal alloy in the general form of relatively short rectangular strips having substantially parallel upper and lower edges and side edges which taper inwardly toward the lower edge and are also tapered from top to bottom.

The size and taper of the blades may be varied to a considerable extent but best results will be secured if the blades are from 1/3 to 1% thick at the top and tapered to to 1% at the bottom, respectively, and with the space between the blades slightly larger than the top faces thereof. The blades preferably are from 5" to 7% in length and about 21/4 deep. The plates 23 and 24 are about 1/2'' thick. This design results in a maximum cooling of the blades with a consequent maximum preheating of the combustion air. In order to secure the requisitestrength and durability the blades and supporting plates may be cast from different metals and alloys but I prefer to employ compositions and processes such as described in the patents to Gray, No. 1,999,153; Jewett et al., No. 2,i)08,452, and Raven et al., No. 2,014,238.

As will be apparent from an inspection of Figs. 2 and 3, the end plates 22 and 23 are of sufficient length at the top to support, a plurality, preferably three groups of blades in end to end relation. The sides of the plates are tapered inwardly toward the bottom and are deep enough to provide a depending web below the lower edges of the blades. The lower edge of each plate is formed with a rather deep centrally disposed slot 33 shaped to seat on the rocking bars Ill, |5 or IB, so that the units will be firmly but removably mounted on the rocking bars.

The upper ends of the slots 33 terminate well below the lower edges of the central group of blades 29 so that the flow of combustion air is not aifected to any noticeable extent by the supporting bars |4, 15 and l. Thus a uniform distribution of air over the entire grate is assured.

While a preierred embodiment of the invention has been disclosed for purposes of illustration, it will be understood that the invention may be applied to other types and forms of grates and that various modifications and changes in the details of construction may be made without departing from the spirit of the invention within the scope of the appended claim.

I claim:

In a furnace grate, a cross bar, means providing a fuel bed supporting surface mounted on said cross bar comprising a plurality of individually removable fuel supporting units positioned on said bar adjacent each other, each of said units com'prising a pair of upstanding end plates disposed in parallel spaced relation, a plurality of thin upstanding blade members supported by and between said end plates in parallel spaced relation and with their upper edges in the plane of the upper edges of said end plates, said blade members being spaced from each other and from said end plates a distance at least as great as the thickness of said blade members, said end plates having depending web portions extending an appreciable distance below the plane of the lower` edges of said blade members, said depending web portions of said plates having downwardly opening slots formed therein to receive said cross bar, said slots terminating at their upper ends below the plane of the lower edges of said blade members to provide a free space for passage of air between the upper surface of said cross bar and the lower edges of said blade members.

CHARLES B. BODINE.

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