US1696041A - Carburetor for powdered coal - Google Patents

Description

Decfl,` 1928..

v O. A. KREUTZBERG CARBURETOR FOR PowDERED coAL Filed Feb. 20, 1924 u u um Patented Dec. i 18, 1928.

UNITED STATES OTT A. KBEUTZBERG, 0F LAKE BLUFF, ILLINOIS.

CARBURETOB FOR POWDERED COL.

Application filed February 20, 1924. Serial No. 694,005.

The purpose of this invention is to pro vide improved means for mixing air and powdered fuel such as powdered coal for immediate use in a heating furnace or kunder a power boiler and susceptible of regulation through fairly wide limits for varying the intensity of the fire and the heat given off thereby. It consists. of certain features and elements in combination as herein shown and describe-d and as 'indicated by the claims.

In the drawings Figure l is a front elevation partly in section as indicated at line 1--1 on Figure 2, illustrating a coal carbureting machine embodying this invention.

Figure 2 is a side elevation showing the coal feed hopper in section.

Figure 3 is a top plan view wit-h the fuel feeding mechanism removed from the feed chamber.

In preparing powdered fuel such as finely pulverized coal for combustion there is of course an ideal proportion preferably to be maintained between the quantity of fuel and the quantity of air furnished for its combustion. Obviously any considerable excess of air over that required for complete combustion will tend merely to absorb heat units and carry them off through the stack while insufcient air will produce a smoky flame and will either encrust the entire combustion chamber with soot or cause combustible carbon to be carried away in the smoke. In various plants the proportion of air supplied with the fuel and that supplied through the draft doors may be varied according to local conditions but in any plant it is desirable to furnish a considerable proportion of the air already mixed with the pulverized fuel.

The apparaus of this invention is designed to do this and since the volumetricV output of a blower varies quite uniformlyvwith its Speed through a considerable range, it is found that by mechanically connecting the fuel feeding` device to the blower so that a certain quantity of powdered fuel isreleased for each revolution of the blower rotor, a practically constant mixture of air and fuel can be maintained through a considerable rr nge of speeds.

As shown in the drawings, the blower is housed in a casing, 1, surmounted by a feed chamber, 2, which may be understood as being located directly below a storage hopper for powdered fuel indicated in dot-ted lines at 3. The blower sha-ft, 4, carrying the blast wheel, 5, is connected Idirectlyto a drive motor, 6, whose speed may be varied in any desired manner; preferably the motor is ofV a variable speed type designed for eihcient operation throughout a considerable range of speeds. l.Vithin the feed chamber', 2, a

port in the lower part of the chamber, 2, giv- `ing access directly to the blower casing, 1,

at its upper portion while the dischargev mouth, 14. of the blower is shown at the lower portion of the casing and yat the same side of the shaft, 4. As the blades, 15, of the wheel, 5, rotate from the outlet, 8, to the discharge mouth, 14, it results that the powdered fuel admitted at the outlet, 8, is picked up by the fan blades, 15, and carried throughalmost a complete revolution of the wheel, 5, in the direction indicated by arrow X on Figure 2, before arriving at the discharge mouth` 14, thus affording ample opportunity for inter# mixture 'of the powdered coal with theair handled by the blast wheel. Though the fuel falls by gravity from the chamber, 2, into the path of the blades, 15, it will be widely dispersed through the air current by centrifugal force so that substantially allthe fuelV will be discharged from the fan wheel during the first revolution and will pass with the air to the combustion chamber of the furnace.

To agitar-e the powdered material in the hopper, 2, just sufliciently to prevent it from packing or clogging therein I provide a cagelike structure comprising two disks, 16, carried on. an axle, 17, and connected in spaced relation by tie rods, 18. The peripheral portion of each disk, 16, is notched and the material cut from the notches is folded up to form blades, 19, radially arranged. These blade portions of the disks, 16, laterally overlap the feeder wheel, 7, anda stud, 20, projecting from one face of saidwheel engages any one of the notches between the blades, 19, so that with each rotation of the feed wheel, 7, the agitator is advanced a. few degrees about its axis Vso as to break up any packing of the fuel mass in the chamber, 2. As the feed wheel, 7, rotates in the chamber, 2, its outwardly open pockets will till with powdered fuel and as these pockets pass the discharge port, 8, they will empty `their loads into the blower. However, the angular cxtent of each pocket is something less than the thickness of the bottoni wall ot the chamber, 2, which the pocket traverses in approaching the port, 8, or leaving it; thus there is always at least one side of one pocket interposed between the feed chamber, 2, and the edge of the port, 8, so that the feeder wheel constitutes a complete closure for the port and no powdered fuel is permitted to leak past the wheel at any position thereof.

I claim:

l. In an apparatus for mixing powdered fuel and air, an air blast wheel and a casing therefor having a tangential discharge mouth, a feed hopper for the fuel mounted adjacent the blast wheel casing and formed with an outlet positioned to direct the fuel toward the periphery of the blast Wheel, and means for positively controlling the feed of fuel from the hopper in lixed relation to the .speed of the blast wheel.

2. In an apparatus ior mixing powdered fuel and air,v a centrifugal blast wheel and a casing therefor, a feed hopper for the `l'uel having an outlet leading into the casing zulyjacent the periphery ofthe blast wheel and measured quantities of the vpowdered fuel to the outlet in fixed relation to the speed of the blast Wheel.

OTTO A. KREUTZBERG.

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