US1483557A - Feeder for pulverized coal - Google Patents

Description

Feb. 12 1924, 1,483,557

G. 2.. SMITH ET AL FEEDER FOR PULVERIZED COAL ,Filed Nov. 13, 1920 2 Sheets-Sheet 1 wl'mzsszs INVENTORS ATTORNE Feb. 12 1924.

G. 2. SMITH ET AL FEEDER FOR PULVERIZED GOAL Filed Nov. 13, 1920 2 Sheets-Sheet 2 WITNESSES ATTDREY Fatented Feb, 12, 1924.

GEORGE z. SMITH. aivn ninwrn B. HERBERT, or roLLAnsBEE, wEsr vrEornIag FEEDER FOR'PULVERIZED COAL. I

Application filed November 13, 1920.- Serial No. 433,891.

To all whom it may concern. I

Be it known that we, GEORGE Z. SMITH and EDwIN B. HERBERT, citizens of the United States of America, and residents of Follansbee, county of Brooke, and State of est Virginia, have invented certain new and useful Improvements in Feeders for PulverizedCoal, of which the following is a specification.

This invention relates to feeding devices for pulverized" material and involves more especially the provision of a pulverized fuel feederfor delivering fuel to a furnace.

In one formof device used extensivelyv in practice for feeding pulverized fuel, for instance, to a furnace, a screw is employed for conveying the fuel from a supply bin to the burner tube of the furnace, through a feed pipe in which the screw is mounted for rotation, the fueldropping by gravity from the feed pipe through a suitable connection to the burner tube from which the fuel is injected into the furnace by means of a blast of air. The screw is connected to driving means, usuallya-motor, and the amount of fuel delivered by the screw in a given time depends upon the speed at which it is driven by the motor. In order that the amount of fuel delivered may be regulated in accordance with the requirements, it is customary to provide a variable speed direct current motor; or when the use of such a motor is not feasible, as where the only available source of electricalenergy is alternating current,to employ a constant speed motor with speed changing devices inter posed between the motor and the screw shaft for varying the speed at which the latter is to be driven. This form of fuel feeder,

therefore, has the disadvantage of depend are at all times driven at constant speed.

Unlike prior mechanisms wherein a screw is dependedupon to propel the fuel to'the point of delivery, 111 accordance with which arrangement the amount of fuel delivered will be governed by the speed of rotation of the screw, the feeding devices, of the apparatus of this invention serve merely to prepare the fuel for deliveryto a casing and to produce a steady uninterrupted flow of fuel into the casing. The rate at which the r I fuelis'fed to the casingis controlledby a valve situated in the inlet opening of the .65 casing for fuel. Manually adjustable means are provided whereby this valve may be set to increase or decrease the rate of flow as desired; also means for discharging the fuel a from the casing through a feed pipe to the point of delivery. i

Preferably the fuel is supplied to thecas v the receptacle to the casing at a rate depend ent upon the valve setting.

In the preferred construction'of the; feedmg devices contained within the apparatus,

propeller blades are included for creating.

a constant upheaval'of the fuel as it de-[v scends from the receptacle, thus keeping the fuel in a state of mobility in preparation I for its delivery to the casing so that its flow through the inlet opening thereof, as regulated by the valve, will be continuous and at a uniform rate fora given valve setting.

These blades are provided with notches through which the fuel falls by gravity to l the inlet opening of the casing.

The invention is illustrated in the accom panying drawings, in which- Figure 1 is a sectional elevation of the invention';

Figure 2 is an enlarged section on line 2-2, Fig. l;

Figure 3 is a top plan view of the feeder casing with the working parts removed therefrom; and

Fi ure l is a perspective view of the fuellifting agitator bar. I

Referring to said draw1ngs,71n which like designating characters distinguish like parts throughout the several views I 1 indicates a hopperlike supplysbin or reservoir for powdered coal.- Attached thereto in underlying relation to its mouth is a basin-like receptacle 2 forming a continuation of the hopper 1 and constituting the bottom portion thereof and which is provided with a central bottom opening 3. Fitted within said opening and projecting upwardly therethrough into the interior of said basin is the upper cylindrical end portion of a casing 1, an external annular flange 5 formed upon said casing being attached,

as by means of bolts 6, to the adjacent opening-defining edge of said basin.

The casing a has located therein at a suit able distance from its upper end an internal annular flange 7 upon which rests a centrally apertured plate 8 constituting a seat for a valve 9 of inverted-cone shape carried by a vertically disposed rotary shaft 10. Said valve seat 8 has its inner peripheral edge upwardly beveled, and the valve 9 is adjustable with respect to the edge for regulating the extent of the valve opening and thus the flow of powdered fuel to the under lying chamber 11 formed by the lower end of the casing.

The shaft has the said valve 9 formed thereon or attached thereto intermediate its ends. 2 That portion of the shaft located above the valve projects somewhat above the upper end of the casing & and carries a horizontally disposed bar 12 having a length approximating the diameter of the bin mouth. This bar rotates with the shaft and acts to stir or agitate the powdered coal for preventing arching or hanging of the latter about the upper end of the casing. To facilitate the lifting of the pulverized fuel the agitator bar has its opposite end portions 12 of beveled form, the bevel 'on one end being oppositely inclined to that on the other end.

from a point closely underlying the agitator bar 12 to a point closely overlying the valve 9 are one or more spiral propeller blades 13 by which, when the shaft is rotated in a forand uniformly through the valve opening in the lower chamber of the casing at a rate depending upon the setting of the valve.

Notches 14 or other suitable forms of openings or recesses are provided at suitable intervals in the propeller blades, and these afford passageways through which the fuel is permitted to pass to lower levels by gravity. In the nearly-seated position of the valve the lower inclined ends of the blades closely overlie the valve seat 8 and constitute scrapers by which the coal is largely prevented from collecting upon the seat. As means for preventing collection of coal upon the seat when the valve is elevated to a considerable height, one or more pins 15 are mounted loosely in vertical positions in the outer edge portions of the pro:

through which the pulverized fuel delivered past the valve 9 is directed to the furnace, the passage being adapted to have a feed.

pipe leading to the furnace coupled thereto. Directed into the chamber 11 at the side opposite the passage 17 so as to occupy a position in direct alinement with the center of the latter is a nozzle 18 through which a continuous blast of air is directed for carrying the fuel to the furnace. The center line of the nozzle and the passage is located laterally with respect to the shaft 10 so that the latter will in no wise interfere with the delivery of the air blast for directing the fuel through the passage.

The shaft 10 extends downward through an opening provided therefor in the bottom of the casing a, a suitable gland, as 19, being provided to prevent leakage. The shaft is mounted in a bearing 20 located at a suitable distance below the casing 4:, this bearing being herein shown as carried by a bracket arm 21 which depends from one side of the basin 2. Also formed on the arm 21 at a suitable point is a bearing 22 in which is journaled a drive-shaft 23 designed to be connected to a constant speed motor, as through a belt operating on a pulley or belt wheel 24 carried by the outer Carried by the shaft 10 and extendingend of said drive-shaft. A bevel pinion 25 carried on the inner end of the driveshaft is cperatively engaged with a bevelgear 26 carried by the shaft 10 in a position directly overlying the bearing 20.

The bevel gear 26 is maintained against rotation on the shaft 10 by means of a key 27 which is loosely fitted in ways 28 and 29 provided therefor in the shaft and the hub of said gear, respectively. The way 28 is of such greater length than the key that any desired vertical adjustment of the shaft 10 may be effected. A yoke 30 which is fitted into an annular groove or channel 31 in the lower part of the hub of the bevel gear, and which is rigidly attached to the upper end of the bearing 20, as by means of screws 41, serves to main tain the bevel gear against vertical movement.

A collar 32 adjustably mounted on the shaft 10 intermediate the gear 26 and the bottom of the casing 4 is designed for adjustment to limit the extent of vertical valveopening movement of said shaft.

The lower end of the shaft 10 is formed with a short reduced neck 33 terminated by too a head34, the latter being also reduced with end wall 37 formed on the bearing 20. The head 35 constitutes: a; seat; upon which'the shaft 10 rests and With respect to which the shaft is freely, rotatable. Fixed uponthe outerend of the screw 36 isa handwheel 4:2

by means of which the screwz'may be rotated for'elevating and lowering the shaft for ad-.

justing the valve 9 with'respect'to itsseat;

8. Arnut 38, preferably provided-with a handle 39 whereby it may be conveniently rotated, is provided for; locking the. screw in adjusted position.

While the screw 36, as described, consti-i tutes an operative means for shifting the position of the shaft in a longitudinal direction to adjust the valve, it will be understood that this is merely illustrative, it being obvious that various other devices for effecting such shifting might readily be substituted therefor. V g r To provide for adjustment of the casing 4 so that the discharge passage 17 may face in any direction most suitable for coupling to a pipe or pipes leading to the furnace, the

openings in the flange 5 for the attaching bolts 6 are in the form of arcuate slots, as shown at in Fig; 3.

vThe valve 9 is preferably formed on its under, or inclined, sides with one or more radial arms or blades 43 of approximately triangular form, as shown, these blades being designed to act within the opening defined by the flange 5for preventing undue collection of fuel in and about the opening.

In practice, the rotating shaft 10' is adjusted vertically to properly position the valve 9 with respect to its seat for permitting of the passage thereby of the powdered fuel in the quantity required for feeding the furnace. The agitator bar 12- carried by the upper end of the rotating shaft acts to produce a constant upheaval of the fuel at and adjacent to the mouth of the bin, whereby arching or hanging of the fuel is effectually prevented and a constant supply of fuel to the interior of the upper part of the casing 4 is consequently assured. The fuel so supplied to the upper part of the casing is subjected by the propeller blades 13 to a constant upheaval which prevents all tendency of the fuel to pack and thus render feeding past the valve more or less irregular or spasmodic. The fuel so acted upon by the blades drops by gravity past the edges of said blades and through the openings or notches 14 thereof, in a steady uniform flow at the rate fixed by the valve setting while the feeding devices including the agitator bars 7 and propeller blades =are-rotated1 at constant speed,.and collection of fuel upon the horizontal ledge of the :valve seat 8- is prevented .by the constantly iactingscraping heads 16 of the pins 15. Havingpassed to the chamber 11 in the lowervpart of the casing,-the fuel is acted upon by thdairb-last Y issuingafrom the nozzle: 18 and is thereby; r

directed outward to 'lthe furnace through the passage-17 in a streain of uniform or ,unvarying :volume; As :is o'bvious,th1s volume maya'be instantly rdimnnshed or 1n- 1 creased. by adjustmentof the'fvalve' toward i or away from its seatwhile-the feeding del i vices-are drivenaat constantspeed. i a B0 1. In a pulverized fuel feederpa casing;

having an inlet opening, :a receptacle, situaated above the casing for' supplying.ifueluto the casing through said inlet,:a' shaft LeXtcnding through :the casing carrying avalveforcontrolling said? openingjandcarrying feedingdevices including spirallpropeller blades,

to elevate-the fueland to keep itin EbCOIlSlZELnt situated above the inletv opening-arranged;

state of upheaval, a motori'fori driving saida: shaft carrying saidfeedingidevices; at constant speed producing, in conjunction with the action of gravity, a steady flow of fuel from the receptacle to the casing at a rate depending upon the setting ofthe valve, and means for discharging the fuel from the casing.

2. In a pulverized fuel feeder, a casing having an inlet opening, a valve controlling said opening, a receptacle for supplying the fuel to the casing through said inlet, means for regulating said valve, feedingdevices interposed between the supply receptacle and the casing, and means for driving said feeding devices at constant speed, said feeding devices including propeller blades having notches therein and being constructed and arranged to produce, when driven at constant speed, and in conjunction with the action ofgravity, a steady flow of fuel from the receptacle and downwardly through said notches to the casing at a rate depending upon the setting of said valve, and means for discharging the fuel from the casing.

3. In apulverized fuel feeder, a casing having an inlet opening, a valve controlling said opening, a receptacle situated above the casing for supplying fuel thereto through said inlet, means for regulating said valve,

feeding devices interposed between the supmounted above the inlet opening of the cas casing by action of said feeding devices assisted b gravity in a steady flow and at a rate cepending upon the setting of said valve, and means for discharging the fuel from the casing.

4:. In a pulverized fuel feeder, a: casing having an inlet opening, a. receptacle for supplying fuel thereto through said inlet, a shaft extending throughthe casing carrying a valve for controlling said opening and feeding devices comprising propeller blades ing, stirring rods loosely mounted in said blades and an agitating bar having triangular shaped blades sloping in the direction of rotation of the shaft and situated in said fuel receptacle, a motor for driving said shaft at a constant speed, and means for discharging the fuel from the casing as it is fed thereto by action of said feeding devices assisted by gravity in a steady flow depending upon the setting of said valve, and means for moving said shaft longitudinally to regulate said valve.

5. In a pulverized fuel feeder, a casing having an inlet opening, a valve controlling said opening, a receptacle for supplying the fucl to the casing through said inlet, means for regulating sa1d valve, feeding devices interposed between the supply receptacle and the casing, means for driving said feeding devicesat a constant speed, said devices lieing constructed and arranged to produce, when driven at constant speed, a steady flow of fuel from the receptacle to the casing at a rate depending upon the setting of said valve, and said casing having an outlet opening for fuel and an inlet opening for air under pressure, said openings being in aline' GEORGE Z. SMITH. EDWIN B. HERBERT. l/Vitnesses J. C; HILsINGER, GEO. L. Homes.

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