US2404848A - Spreader stoker apparatus - Google Patents

Description

July 30, 1%, W. KEssLER SPREADER STOKER APPARATUS Original Filed July 25, 1943 INVENTOR WILBU R KESSLER ATTORNEY FIG 3.

FIG. 2. E

WITNESSES:

. MW, yfl Www Patented July 30, 1946 SPREADER STOKER APPARATUS Wilbur Kessler, Newtown Square, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application July 23, 1943, Serial No.

495,807, now Patent No. 2,390,155, dated Decemher 4, 1945. Divided and this application May 5, 1945, Serial No. 592,112

This invention relates to stokers, more particularly to stokers of the spreader or sprinkler type, andfhas for an object to provide improved apparatus of this character.

To the best of applicants knowledge, most industrial spreader-feed stokers on the market fail to provide uniform distribution of fuel laterally of the grate surface. The bed of fuel deposited thereon is generally thin along the lateral edges of the area of distribution of each feeder unit; and, where a plurality of such units are employed in a furnace, the space on the grates between the feeders is nearly empty of fuel adjacent the furnace front wall, this nearly empty area being triangular in shape with its base at the front wall and having an altitude longitudinally of the grate of from 2 to 3 feet.

Large quantities of excess air 'are admitted to the combustion chamber through the nearly empty spaces on the grates and the thin portions of the fuel bed at the lateral edges. 'As a result, either a high furnace or a high degree of turbulence is necessary to make this excess air useful for combustion.

Therefore, another object of the invention is to provide a spreader fuel feeder for stokers which will provide more uniform lateral distribution of the fuel laterally of the furnace than has been obtainable heretofore.

A further object of the invention is the provision of a fuel-feeding mechanism for delivering a greater quantity of fuel to the end portions of a fuel-impelling device, than is delivered to the intermediate portion thereof.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a plan view of a furnace fed by a pair of conventional spreader units, and illustrating the problem which applicant is solving;

Fig. 2 is a plan view of a construction of the invention, taken along the line 11-11 of Fig. 4, looking in the direction indicated by the arrows;

Fig. 3 is a sectional View taken along the line IIIIII of Fig. 2, looking in the direction indicated by the arrows; and

Fig. 4 is a sectional view taken along the line IVIV of Fig. 2, looking in the direction indicated by the arrows.

Referring now to the drawing more in detail, with particular reference to Fig. 1, there is shown a furnace l0, comprising a front wall ll, side walls l2, and. a rear wall l3, the front wall ll 2 Claims. (Cl. 110-415) 2 Y having a pair of openings [4 therein, through which fuel is fed by the spreader units Hi to the grate structure 16 forming the bottom of the furnace combustion chamber. In this figure, the numeral l8 indicates the fuel bed as normally deposited upon the grate surface by the conventional industrial spreader stoker units now on the market. The lateral areas of relatively thin fuel deposits are indicated by the reference character [9, while 26] indicates the portions of the grate surface which are nearly empty of fuel and through which large quantities of excess air pass from the plenum chamber below the grate structure to the combustion chamber thereabove.

In order to make up for the deficiency of fuel along the lateral portions of the fuel de-.

posits upon the grate surface, it is proposed to feed to the edge or end portions of the impellers of the spreader units, a greater quantity of fuel per unit area of ram face than is delivered to the intermediate portions of the impellers, and Figs. 2, 3 and 4 illustrate one form of apparatus for providing this additional supply of fuel.

Referring now more particularly to Figs. 2, 3 and 4, fuel is fed from the hopper 22 by rams 23 and 24 rearwardly over the spill plate 26 to the rotary impeller 21 disposed therebeneath, the blades of the rotary impeller projecting the fuel fed thereto rearwardly through the furnace front wall opening M to the grate 16 in the bottom of the furnace.

Reciprocatory motion is adapted to be imparted to the rams 23 and 24 of each spreader unit l5 by a single oscillating shaft 30, carrying crankarms 3| and 32, the former being connected to the central ram 23 by links 33 and the crankarms 32 being connected to the side rams 24 by links 34.

As best shown in Fig. 4, the links 33, providing the driving connection for the central ram 23, include a lost-motion connection 36 between the links 33 and the crankarms 31, by which the stroke of the central ram 23 may be varied by adjustment of the handwheel 31. Inasmuch as the links 34 providing the driving connection for the side rams 24 are of fixed length, it will be apparent that it is possible to vary the relative lengths of the feeding strokes of the rams 23 and 24. Inasmuch as the three rams are driven from the common shaft 30, it will be apparent that, if the central ram 23 has a shorter stroke.

than the side rams 24, the latter will deliver a greater quantity of fuel to the corresponding side or end portions of the rotary impeller 21, thereby providing excess fuel at these locations tending to minimize thinness of fuel bed at the edges of the areas fed by the spreader units.

This application is a division of my copendin application Serial No. 495,807, filed July 23, 1943, now Patent No.;2,390,155, granted December 4, 1945. t

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a stoker, fuel-feeding mechanism comprising a hopper; an impeller; areciprocal ram structure for pushing fuel from the hopper to the impeller, said ram structure comprising an' intermediate ram and an end ram at each side of said intermediate ram; means for imparting reciprocatory motion to the intermediate ram to cause it to deliver fuel to the corresponding intermediate portion of the impeller at a predetermined rate; and means for imparting reciprocatory motion to the end rams to cause them to deliver fuel to the correspondinglend portions of the impeller, said last-mentioned means providing a longer working stroke of the end rams than of the intermediate ram, whereby said end rams deliver more fuel per unit area of ram face than does said intermediate ram.

. 2. In a stoker, fuelfeeding mechanism comprising a hopper; an impeller; a reciprocal ram structure having an effective width transverse to the direction of its reciprocation substantially equal to the length of the impeller in the same direction, said ram structure comprising a spaced pair of end rams and one or more intermediate rams therebetween; means for imparting reciprocatory motion to the intermediate ram or rams to cause them to push fuel from the hopper to the intermediate portion of the impeller; and means for imparting reciprocatory motion to the end rams to cause them to push fuel from the hopper to the corresponding end portions of the impeller, said last-mentionedmeans providing a longer working stroke of the end rams whereby said end rams deliver more fuel per unit area of ram face to the corresponding end portions of the impeller than the intermediate ram or rams deliver to the intermediate portion of the impeller.

" WILBUR KESSLER;

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