US2284760A - Stoker furnace - Google Patents

Description

June 2,- 1942. c. L. MYERS I 2,284,760

STOKER FURNACE Original Filed June 3, 1936 Patented June 2, 1942 i I ican Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Original application June 3, 1936, Serial No.,

1939, Serial No. 274,719

2 Claims. (01. 122-4) This application is a division of my co-pending application filed June 3, 1936, under Ser. No. 83,281, and now issued as Patent 2,185,865, Jan.

2, 1940, and the invention embodied herein relate's to stoker furnaces, and more particularly to stokers of the inclined grate, multiple retort underfeed type.

One object of the present invention is to provide a novel and highly improved stoker of the stated character, capable of functioning throughout the operating range of the furnace to effect complete combustion of the fuel with the use of a minimum of excess air, thereby insuring maximum furnace temperatures under all conditions of operation. 1

Another object is to provide an improved stoker construction which requires a minimum of headroom, and therefore is adapted for use in commercial plants of varied sizes.

Another object is to provide in a stoker of the stated character a novel ash disposal means for the refuse fed from the stoker.

. A more specific object is to provide in a stoker of the stated character a slag pit for receiving the residue fed from the stoker wherein such residue is maintained in a liquid state, and any combustible matter contained in such residue separates therefrom and floats on top of the molten mass where it is brought into direct contact with a combustion supporting gas and com pletely burned before the molten residue is drawn from the furnace. I

A further object is' to provide in a stoker furnace, novel means for liquefying and maintaining in a liquid state the residue fed from the stoker to the slag pit, and to provide means for directing air over the top of theslag pit and into direct contact with the combustible matter separating from the refuse as the latter is liquefied to effect complete burning thereof, said aid thereafter passing over the fuel bed of the stoker where it combined with the combustible gases driven from the fuel to insure complete combustion thereof.

Other and further objects will become apparent as the description of the invention progresses.

Of the drawing the single figure is a sectional elevational view taken through one of the retorts of the stoker showing a still further modification of the present invention.

The drawing discloses a furnace fired by an underfeed stoker 3 comprising alternately disposed retorts 4 and tuyere rows 5. The lower end of the stoker terminates in an extended overfeed section I0'I which is constantly vibrated Divided and this application May 20,

by any suitable vibrating mechanism indicated at I02 to feed the fuel fed from the stoker 3 proper into a slag pit 14 disposed at the rear end thereof. Fuel is fed to the retorts from hoppers 6 by a series of fuel feeding rams operating in cylinders 1 and driven by any suitable power mechanism 8. Fuel is underfed along the retorts by a series of, pushers 9 mounted in the bottoms of the retorts and operatively connected to the power mechanism 8 by a link and lever mechanism I0.

The overfeed section IOI is cooled by a series of fluid conducting tubes I03 mounted in cooling relation therewith. Tubes'l03 are connected at the lower ends thereof to a header I04 disposed beneath the stoker, and secured to a suitable framework I05 and terminate at their upper ends in a header I06, also secured to said framework I05. The framework I05 is operatively connected to the vibrating mechanism I02, and consequent ly the impulses imparted thereto by said mechanism are transmitted to the overfeed section IOI through tubes I03. This vibratory movement of overfeed section IOI effectively feeds the fuel and refuse therealong to slag pit W.

The front wall I01, and the bottom wall I09 of slag pit I I in the present instance may comprise a series of air cooled refractory blocks I08 and H0 respectively. The rear wall of the furnace consists of a series of block covered tubes I I I extending upwardly from a transversely disposed header II2. Tubes III are bent so asto extend forwardly and upwardly, as shown at II3, to form an arch II l overlying the slag pit I I and the overfeed section IIlI of the stoker, said tubes terminating at their upper ends in the mud drum H5 of the boiler. The side walls II6 of the furnace may be constructed of a series of air cooled refractory blocks III, or of any other heat resistive means.

In this construction a series of nozzles 5| extend through the rear wall of the furnace and direct air at high velocities over the top of the slag pit to effect burning of any combustible material contained in the refuse. This air is then directed over the top of the fuel bed to effect complete burning of the combustible gases driven from the fuel. In this construction also by virtue of arch II4 an extremely hot zone is created over the slag pit and the overfeed section of the stoker whereby the refuse fed thereto is maintained in a liquid state. This liquid ash may be withdrawn from the pit from time to time through a suitable tap 14. In this construction it will be noted that the fuel feeding elements 9 of the stoker 3 are located a considerable distance from the rear most end of the overfeed section thereof, and thus are shielded from the molten slag forming in the furnace by green fuel. Burners 66 may also be provided in the side walls of the furnace to supply additional heat thereto when desired. Nozzles 5l may also have connected thereto branch pipes 61 for conducting an auxiliary fuel to the furnace from a supply line 65 if it is so desired.

From the foregoing description it is seen that by reducing the ash content of the fuel to a liquid state, troublesome ash handling problems are completely eliminated. It is also seen that by treating the ash in this manner the fixed carbon and other combustible matter contained therein separates from the ash and floats on top of the molten mass. This combustible matter being directly exposed to incoming air is completely burned and as a result of the combustible matter contained in the fuel fed to the stoker is consumed, with the use of a minimum of excess air. The furnace therefore operates at high efliciencies inasmuch as the gases generated therein are maintained at maximum temperatures. It is also seen that by passing a certain quantity of air over the fuel bed, as well as over the combustible matter floating at the top of the ash pit it is unnecessary to feed all of the air for combustion purposes through the grates of the stoker. Blowing of the fuel from the fuel bed is thus prevented, and as a result the fuel bed remains normally uniform throughout the operation of the furnace. By treating the ash in the novel manner set forth herein, it is also apparent that a relatively shallow slag pit may be provided, and consequently the headroom requirements of the unit as a whole are reduced to a minimum.

While the embodiment herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that the invention is not to be limited thereto since it may be embodied in other form, all coming within the scope of the claims which follow.

What is claimed is:

1. An overfeed section for stoker furnaces comprising, a fuel supporting portion, fluid conducting tubes mounted in cooling relation with said fuel supporting portion and forming a support therefor, headers connected to the opposite ends of said tubes, a framework for supporting said headers, and means comprising a vibratory mechanism operatively connected to said framework for imparting rapid vibratory impulses thereto and consequently to said tubes and fuel supporting portion whereby the fuel supported on said fuel supporting portion is progressively advanced from one end thereof to the other.

2. An overfeed section for stoker furnaces comprising a framework, a pair of spaced headers mounted in said framework, a series of fluid conducting tubes extending substantially horizontally from one of said headers and being bent downwardly and reversely substantially in the form of a U and terminating in the other of said headers, a fuel supporting means mounted on a portion of said tubes, a resilient support for said framework, and means comprising a vibrating mechanism operatively connected to said framework for imparting rapid vibratory impulses thereto and consequently to said tubes and fuel supporting means whereby the fuel supported on said overfed section is progressively advanced from one end thereof to the other.

CHARLES L. MYERS.

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