US2349448A - Grate for boilers, furnaces, and the like - Google Patents

Description

May 23, 1944. G. Mmx

GRATE FOR BOILERS, FURNACES AND LIKE Filed NOV. 15, 1941 INVEN TO W GEORGE 6 MARX B JMM $72k M4 ATTQRNEYS Patented May 23, 1944 UNITED snares earaur {orrlce GRATE FOR BOILERS, FURNACES, AND THE LIKE George G. Marx, Detroit, Mich.

Application November 13, 1941, Serial No. 418,933

2 Claims.

The present invention relates to grate structure for boilers, furnaces and the like, and has among it objects a grate structure which will provide for more efficient combustion, particularly at the outer sides of the mass of burning fuel.

Another object is a grate structure which will provide, without blowers or other mechanical blast producers, a forced draft of preheated air to such outer portions of the fuel.

Still other objects and advantages will readily occur to those skilled in the art upon reference to the following description and the accompanying drawing in which Figure 1 is a perspective view, with a part broken away, of one of the grate bars.

Figure 2 isa section on line 3-3 of Figure 3 but showing a grate bar in elevation.

Figure 3 is a plan view of a portion of the grate structure.

Figure 4 is a side elevation thereof.

In the drawing, there is shown at I!) a modified form of a grate bar, such as is shown in my prior United States Letters Patent No. 1,925,840, dated September 5, 1933, for Furnace grate, and consisting of a body portion ll having notched sides and having slots l2 extending vertically therethrough.

As in the patented form, these slots l2 form ports of passages extending lengthwise of the bar, those in the alignment being connected by openings the cross members It and the end slots being connected by openings It to chambers l5 formed at the bar ends.

These chambers l5 likewise have opening H5 in their end faces preferably somewhat larger than the openings I4 and on each side of the trunnions ll with which each bar is provided. Also, as in the patented structure, passing up through each chamber I5 i a passage or slot l8.

A plurality of such bars is used to form a complete grate and these are supported by means of the trunnions IT in notched grate rests 2!] running longitudinally of the firebox of a furnace structure and supported on suitable legs 2i or on suitable means at the front and rear of the firebox. Each of the plates 20 is provided with openings 22 on each side of a notch 23 and normally opposite one of the openings l6. Further, each of the plates 20 is provided with a plurality of brackets 25 serving to space the plate from the wall 26 of the firebox and also serving to support a plate 21 provided with a plurality of openings 28.

It will be noted that while the grate bars I I are somewhat crowned to facilitate ash removal when shaking, the side margins of the grate structure including the plates or bars 21 present a flat surface. The reason for this arrangement is to facilitate ash removal by means of a suitable slice bar or the like. These portions being stationary and flat, running the bar along over the fiat surface causes the accumulated ash to readily fall through the openings 28 and past the grate bar ends.

In order to provide for working the fire each grate bar is of course provided with a suitable arm 30, these being connected with a suitable shaking lever (not shown).

In firing a furnace provided with the present grate structure, the preferred method is to heap up the fuel at the central area of the firebed, leaving the edges of the bed relatively thin.

This offers greater resistance to the passage of air in the central portion and forces a large part to travel longitudinally of the grate bars and travel up through the fire bed near the walls of the firebox;

In traveling lengthwise of the heated grate bars, the air of course becomes highly heated and, therefore, providing a more eiiicient combustion medium, causes a greater portion of the combustion to take place adjacent the firebox walls, i. e., adjacent the boiler legs.

Further, with the greater part of the active combustion occurring outside of the main mass of fuel, distillation and coking of fresh fuel causes more efficiently the formation of a crust of fuel on the top of the main bed, and thereby forces the distillation gases toward the Zone of combustion at the edge.

It is preferred, therefore, to maintain the fuel bed by adding fresh fuel to the central portion of the grate, working the burning fuel toward the sides as the fresh fuel is added. In this fashion, and with the hot air supplied largely to the sides, most of the combustion takes place at or near the water leg or furnace wall.

Now having described the invention and the preferred embodiment thereof, it is to be understood that the invention is to be limited, not to the specific details set forth in the specification, but by the scope of the claims which follow.

I claim:

1. A grate structure for a furnace consisting of a plurality of grate bars having vertical air channels and having longitudinal air passages connected therewith, said passages being open to the ends of said bars, a grate rest for said bars, said grate rest having openings adapted to register with the open ends of said passages, whereby to provide continuous air channels from beyond said rest to said vertical air channels, means for spacing said rest from the side wall of the furnace, and a perforated cover plate for the space so produced.

2. A grate structure for a furnace having sidewalls, said structure including a plurality of grate bars each having a plurality of vertical air channels and having air passages extending longitudinally and connected to said channels, an air 1 chamber in each end of said bars and connected to 0 chambers.

GEORGE G. MARX.

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