US1395486A - Traveling-grate stoker - Google Patents

Description

w. M. DUNCAN.v TRAVELING GRATE STOKER. APPLICATION FILED APR. 17 1919.

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W. M., DUNCAN.

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APPLICATION FILED APR, I7; |919.

Patented Nov. 1, 1921.

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A TTORNE Y 'UNITED STATES PATENT OFFICE.

TRAVELING-GRATE STOKER.

Specification of Letters Patent.

Patented' Nov. 1, 1921.

Appucationmea April 17, 1919. serieu No. 290,665.

To all rwhom t may concern Be it known that I, VILLIAM M. DUNCAN, a citizen of the United States of America, and a resident of Alton, in the county of Madison, State of Illinois, have invented certain new and useful Improvements in Travcling-Grate Stokers, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

y invention relates to improvements in traveling grate stokers, the invention having forits object the production of a grate of this type in the use of which the following points of merit are attained, viz., the avoidance of loss of fine fuel through the air passages in the grate; increased air space for the support of combustion; and an arrangement at the top surface of the grate whereby the fuel deposited upon the grate, is deflected lupwardly at an incline relative to the direction of travel of the grate to facilitate the passage of air into the fuel as the air ascendf through the grate. Other features of novelty in my grate will be hereinafter pointed out and fully described in addition to those here enumerated.

Figure I is a longitudinal section through the forward portion of an endless chain grate having my invention incorporated therein, and other portions of a mechanical stoker with which the chain grate is associa-ted.

Fig. II is an enlarged top view of one of my links.

Fig. III is a side elevation of one of the links.'

Fig. IV is an end view.

Fi V is a vertical cross section taken on line -V, Fig. IIL'through the upper portion of the link.

In Fig. I of the drawings I have shown a collection of my links incorporated inthe traveling chain grate A of mechanical stoker, the stoker also including a frame B, a grate driving member C shown in the form lof a sprocket wheel fixed to the shaft D and Aby which the chain grate is driven in the direction indicated bythe arrow. The Stoker alsopreferably includes a hopper E from which coal or other fuel is delivered to the grate as is usual in the operation of mechanical stokers.

The traveling chain grate comprises rows of grate links F connected together by means of pivot rods @has is wellunderstood in this art. Each ofthe grate links I have shown comprises a web 1 provided with hollow bosses 2 in which the pivot rods are mounted. In the preferred form of the invention the web l is formed with a wedge-shaped top margin 3, the relatively sharp edge being at the top of the web, and a longitudinal row of fuel supporting ribs or tongues 4 extending laterally from opposite sides of said wedge-shaped top margin to form the fuel supporting top of the link. The fuel supporting tongues are separated from each other to provide open draft passageways at opposite sides of the wedge-shaped top margin 3. By combining these fuel supporting tongues with the sharp upper margin of the web 3, I provide for the delivery of air tol almost all of the fuel resting upon the top of the grate link. These draft passageways extend approximately from one side of the the fuel supporting surface tothe other, for the sharp upper margin 3 does not materially interfere with the delivery of the draft to the fuel above the longitudinal center line of the grate link. The entire upper margin of the grate link -is therefore cooled by the rising air currents, and combustion is very materially facilitated by the delivery of air to all of the fuel on the grate.

The fuel used with mechanical stokers having grate links of the type herein shown, is usually fine coal, and although the many ldraft passageways are open at the top for the delivery of airto approximately all of the fuel, I desire to prevent the fine fuel from dropping through these draft passageways. The upper portions of the fuel supporting tongues 4 are, therefore, extended upwardly at an angle, so as to overlie the draft passageways between said tongues. If desired, the tongues 4, which extend over the sharp upper edge ofthe wedge-shaped portion 3, may overlap each other as shown in Fig. III. By extending the fuel supporting tongues in this manner, I prevent fine coal from dropping freely through the draft passageways, and at the same time enable the draft to pass freely through the open top of the grate link.

It is likewise important to observe that the top faces of the fuel supporting tongues 4 are inclined upwardly from the open upper ends of the draft passageways. When a grate link is traveling under the fuel inlet at the bottom of hopper E (Fig. I) the link must form a support for fuel in the hopper, and at this time the top face of the grate will slide, to a certain extent, on the bottom face of the body of fuel. Whenever this action occurs, the inclined top faces 0f the tongues 4 will deflect the fuel upwardly and away from the draft passageways, as suggested by the dotted line X in Fig. Ill. The fine coal at the bottom of the hopper E is usually hot and it tends to lie in a compact mass, so this coal will ybe readily deflected under the conditions just vpointed out, to form small arches over the draft passageways, approximately asindicated by the dotted line X. Uf course, such arches will not be perfectly formed, but the inclined top faces of the fuel supporting tongues 4 will readily deflect the relatively stationary coal upwardly and away from the draft passageways. The coal is thus prevented from being forced through, vor

` scraped into, the draft passageways when the grate link passes under the fuel inlet. Note that the top faces of the fuel supporting tongues 4 are inclined upwardly in aV direction opposite to the direction of travel of the grate. If a grate link was reversed, end for end, its tongues 4 would tend to scrape the fine fuel from the hopper E and into the draft passageways, instead of performing the useful function of deflecting the fuel away from said passageways.

If the bottom face of the fuel would be arched, as shown at X in Fig. III, between all of the adjacent tongues 4, an ideal condition would be obtained, and the draft would be most effectively delivered to all of the arched faces. However, some of the coal and ashes will eventually slip downwardly on the inclined top faces lof tongues 4, and as a further precaution to prevent this fine material from dropping through the draft passageways, pockets 7 may be formed at the lower ends of the inclines on said top faces. These pockets, or the like, are preferably formed at the open upper ends of the draft passageways, so as to prevent free slippage of material at the lower ends of the inclines. l

Iclaim:

l. In a mechanical stoker provided with a fuel inlet, a traveling grate comprising grate links movable under said fuel inlet, each of said grate links comprising a web havingat its ltop margin a longitudinal row of fuel supporting tongues which extend laterally from said top margin to form the fuel supporting top of the link, said fuel supporting tongues being separated from each other to provide a longitudinal row of draft passageways between them, and said row of fuel supporting tongues being provided with extensions having inclined top jfaces for deiiecting the fuel away from the open upper ends of Said draft passageways, the inclinaprovide draft passageways between them,V

the top faces of said fuel supporting tongues being provided with fuel retarding :pockets at the open upper ends of said draft passageways, and said top faces being inclined 11P- wardly from said pockets in a direction opposite to the direction of travel of the grate, whereby the fuel is deflected away from said upper ends of the draft passageways. Y

3. A. mechanical Stoker provided with a fuel inlet, a row of traveling grate links movable-under said fuel inlet, each of :said grate links comprising a web having Yat its top margin a longitudinal row of fuel supporting tongues which extend laterally from said top margin to form the fuel supporting top of the link, said fuel supporting tongues being separated from each other to provide a longitudinal row of draft passageways between them, the upper margins of said longitudinal row of fuel supporting tongues being extended upwardly at an angle so as to overlie the open upper ends of said longitudinal row of draft passageways, and said fuel supporting tongues being provided with inclined top faces for deflecting the fuel away from said open upper ends of the draft passageways, the inclination of said top faces being upwardly ina direction opposite to the direction of travel of the grate. v

4. A mechanical stoker provided with a row of traveling grate links, each of said grate links comprising a web having a wedge-shaped top margin, the substantially sharp edge being formed longitudinally of and at the top of the web, and a longitudinal row of fuel supporting tongues extending laterally from opposite sides of said wedgeshaped top margin to form the fuel supporting top of the link, said fuel supporting tongues being separated from each other to provide draft passageways between them at opposite sides of said wedge-shaped top margin, the upper portions of said fuel supporting tongues being extended upwardly a-nd over said sharp edge, so as to overlie said draft passageways, and said fuel supporting tongues being provided withv inclined top faces which extend' upwardly from the open upper ends of said draft passageways,

5. In a mechanical stoker provided with a fuel inlet, a row of traveling grate links movable under said fuel inlet, each of said traveling grate links having, at its top margin, a longitudinal row of fuel supporting tongues which extend laterally from said top margin to form the fuel supporting top of the link, said fuel supporting tongues being separated from each other to provide a longitudinal row of open draft passage- Y Ways between them, said fuel supporting tongues being provided with extensions projecting over the open upper ends of said draft passageways so as to overlie the row of open ends, and said extensions being pro- 15 vided With inclined top faces for defleotin the fuel from the open upper ends of sai draft passageways, and the inclination of said top faces being upwardly in a direction opposite to direction of travel of the grate 20 links.

In testimony that I claim the foregoing I hereunto affix my signature.

WILLIAM M. DUNCAN.

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