US1197799A - Feeder for pulverulent fuel. - Google Patents

Description

E. C. COVERT.

' FEEDER FOR PULVERULENT FUEL.

APPLICATION FILED OCT. 28, 1915.

1 a 1 97,?99; lam-m1 Sept. 12. 1916.

W'iYNESSES verulent or finely divided fuel, such as coal.

lack of uniformity of feed, and a tendency UNITED STATES PATENT OFFICE.

EDSON C. COVERT, OF NEW KENSTNGTON, PENNSYLVANIA, ASSIGNOR TO HEYL &

PATTERSON, INC., OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

Specification of Letters Patent.

Patented Sept. 12, 1916.

Application filed October 28, 1915. Serial No. 58,413.

of New Kensington, in the county of Vestmoreland and State of Pennsylvania, have invented a new and useful Improvement in Feeders for Pulverulent Fuel; and I do hereby declare the following to be'a full, clear, and exact description thereof.

My invention relates to a feeder for pul- The most efficient feeder for pulverized coal is one that is always under perfect control, and for this reason devices of this character have come to be known as controllers. The difficulties most commonly encountered in the use of these controllers are,

of the coal to continue to flow after the controller has stopped. This tendency to flow, which is sometimes called flooding, is due to the very small angle of repose of dry pulverized coal, and this is accentuated, the drier and morefinely pulv :ized the coal. Nearly all the mechanical controllers of this character employ some form of screw as a means of feeding, but on account of flooding the amount delivered to the burner is subject to considerable fluctuation and the stoppage of the flow of coal when the screw stops is by no means assured. Furthermore, where air is used for feeding the coal from the controller to the burner, the amount of pressure has considerable influence on the quantity of coal that is delivered.

The object of my invention is to provide a controller or feeder of such character that the coal will be delivered in practically uniform quantities, and one which when the feeder is at rest, shuts off the supply of coal completely and prevents flooding heretofore referred to. v

To these ends, my invention consists, generally stated, in combining two screw-feeders in such a way that neither can feed independently of the other and that when at rest, each seals the other against the passage of any material. This is accomplished by mounting two screws of similar size and pitch and of the same hand with their axes at such an angle to each other that a line on the surface of one thread of one screw is in approximate contact with a line on the surface of the space on the other screw; This line of Contact being common to both screws, it is evident that the thread of one screw effectually fills the space of the other. Thus the free flow of material along either screw is prevented.

In the accompanying drawings, Figure 1 is a plan view partly broken away, of my improyed feeder or controller; Fig. 2 is a side view partly broken away; and Fig. 3 is a section on the line 3-3, Fig. 1.

In the drawing, the numeral 2 designates a suitable housing or casing having the material-receiving chamber 3, the discharge opening 4, and two cylindrical intersecting passages 5 connecting the receiving-chamber with the discharge opening. The inter secting passages communicate attheir point of intersection as at 5. Mounted in the passages 5 are the'feed- screws 6 and 7, said feed-screws engaging where said passages intersect, and being. arranged with their axes at such an angle to each other that a line on the surface of one thread of one screw isin approximate contact with a line on the surface of one space of the other screw. This line of contact being common to both screws, it is evident that the thread of one screw effectually fills the space of the other, and thus the free flow of ma-' terial along either screw is prevented. The screws are provided with the pinions 8 driven by the intermediate pinion 9, so that the screws rotate in the same direction. As

both screws are restrained from endwise cept against the movement of material at a faster rate of travel than would be produced by the rotation of the screws. There is thus obtained a uniform feed proportionate to the rate of movement of the screws and absolute stopping of the feed while the screws are at rest. In this manner, fioodingis prevented, and the uniformity of feed is obtained by reason of the fact that there is no flow of fuel except as it is advanced by the screws, and when the screws. stop, the flow of fuel absolutely ceases.

What I claim is: v 1. In a feeder or controllerrfor pulverulent fuel, the combination with a suitable casing, an inlet opening, a discharge opening, two feed screws located in said housing adapted to rotate in the same direction and having their threads in'engagement throughout a portion only of the length of the screws to seal the discharge opening.

2. In a feeder or controller for pulveru lent fuel,-the combinationof a suitable casing, having an inlet and discharge opening;

" two screws located in said casing with their axes at an angle to each otheradapted to rotate in the same direction, and having threads in engagement with each other.

3. In a feeder or controller for pulverulent fuel, the combination of a suitable casing, having an inlet and discharge opening;

two screws located in said casing with their fuel delivery passages, two conveyer screws located in said passages with their axes at an angle to each other, and their threads in full engagement at a point in said passages.

5. In a feeder or controller for pulverulent fuel, the combination of. a suitable casing, having inlet and outlet openings, a con-'- veyer chamber having two fuel delivery passages connecting the inlet and discharge and crossing each other, said passages communicating at the point of intersection, two conveyer screws in said passages having their threads engaging at the point of intersection of said passages, and means for driving said screws in the same direction.

6. In a feeder or controller for pulveru lent fuel, the combination of a suitable casing, having inlet and discharge openings, a conveyer chamber interposed between said inlet and discharge and provided with two delivery passages at an angle to each other and intersecting at a point intermediate said inletand discharge, two conveyer screws in said passages with their screws in engagement at the intersection of said passages, and means for rotating said screws in the same direction.

7. In a feeder or controller for pulverulent fuel, the combination of a suitable casing, having inlet and discharge openings, 31 and a conveyer chamber interposed between said openings, said conveyer chamber having intersecting conveyer passages com- I municating with the said inlet and discharge openings, and conveyer screws in said passages with screws of like hand and in engagement with each other at the intersecting point of the screws at the intersection of said passages.

In testimony whereof, I, the said EDSON C. COVERT, have hereunto set my hand.

, EDSON C. COVERT. Witnesses: v

JOHN F. WILL, J. R. KELLER.

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