US2011133A - Pulverized fuel feeder - Google Patents

Description

Aug. 13, 1935. YOSS 2,011,133

PuLvEEIzED FUEL EEEDEE Filed June 1o, 1952 4 sheets-sheet 1 wlTNEss v Zmvmel 168.6, BY 7M@ ATTORNEY Aug. 13, 1935. E. Yoss 2,011,133

l PULVERI ZED FUEL FEEDER Filed June 10, 1932 4 Sheets-Sheet 2 INVENTOR WITNESS' Emanuel YOSS, L@ n BY I ATTORN EY E. YOSS Aug. 13,` 1935.

Patented Aeg. 13, 1935 PATENT IoFFlcE y rULvEalzEn FUEL FEEDER Emanuel Yoss, Richmond, Va. l

Application June 10,

5 Claims.

My invention relates to improvement in` devices for feeding pulverized fuel, such as pulverized coal, and it consists in the combinations, y constructions and arrangements herein described 5 and claimed.

In the feeding of powdered coal into furnaces, difculty has been experienced in regulating the amount fed, and this has resulted in overheating at certain times and underheating at others. The chief difficulty lies in the fact that in the ordinary coal feeding devices, no matter how finely the coal may be pulverized there is a. tendency for the coal to bridge over in the hopper due to packing. By the term packing I mean that there is a tendency for the particles of coal to adhere so that when the coal at the lower portion ofthe hopper is fed out the bridging of the coal may cause the feeder wheel to revolve idly until the coal body has broken down and again reaches the feeder wheel.

Another reason for the uneven feeding of coal by the ordinary devices is that the powdered coal tends to crowd past the edges of the moving wheel, thus feeding more coal at times than is desired.

An object of the present invention is to provide a device by means of which this tendency to pack or to bridge over is obviated. I have found that where air is introducd into the body of the coal, thus aerating the coal, it will not pack or bridge over but will move uniformly down upon the feeder wheel.

A further object of the invention is to provide means for eliminating the passage of the coal past the feeder wheel, as for instance at the ends thereof.- This I accomplish by means of adjustable members for taking up the wear.

` A further object is to provide a novel form of feeder wheel having conical recesses in its ends so that the coal has no vertical drop at the ends as it has with ordinary feeder wheels, but rests upon the feeder wheel and upon cone-shaped adjustable members which tend to prevent any clogging of the coal as well as to prevent the passage of the coal between the wheel and the adjustable members.

A further object isto provide a feeder wheel and an aerated coal body in which the amount of air is definitely and accurately adjusted to properly suit the amount of coal delivered at any given speed of the feeder. This makes it possible tp regulatethe required amount of heat with the minimum amount of coal, thereby establishing an emcient means of burning pulverized coal.

A further object is to provide a feeder wheel having accurate cavities milled at both ends 1932, Serial No. 616,519

(Cl. 22h-i136) whichare so spaced as to deliver a uniform flow of coal with each complete revolution thereof, the cavities at one end being oifset or staggered with respect to the cavities at the other end.v

A further object of the invention is to provide a device in which pneumatic means is used for conveying the coal delivered from the feeder wheel while at the same time obviating back pressure which might tend to vary the amount fed.

Other objects and advantages will appear in the following specification and the novel features of the invention will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings forming part of this application in which:

Figure 1 is a general view in side elevation showing one embodiment of my invention.

Figure 2 is an enlarged sectional detailed view along the line 2 2 of Fig. 1.

Figure 3 is a sectional view through the main .portions of the feeder mechanism, certain parts being shown in elevation.

Figure 4 is a sectional view at right angles on the line 4-4 of Fig. 3.

Figure 5 is a. plan view of the feeder wheel.

Figure 6 is a sectional view of an adjustable pulley.

Figure 7 is a sectional view on the line 'l-l of Fig. 6.

Figure 8 is a detail sectional view of a portion of the means for introducing air into the hopper and for preventing the coal from getting into the air pipe, and

Figure 9 is a sectional detailed view of a pawl construction.

Referring now to Figure 1 I have shown thereinC a chute l0 leading to a bunker Il having a lower tapered portion Ila. Within the bunker is a transverse shaft l2 bearing a pair of oppositely disposed agitators I3. The shaft I2 extends through one wall of the bunker and is provided with a ratchet wheel I4. The means for operating this ratchet wheel will be explained later. Referring now to Fig. 3 I have shown therein a hopper having inclined walls I5, and provided with laterally extending flanges I6, by means of which the hopper is secured to the bottom of the bunker. A slidable gate I1 is'disposed at the bottom of the bunker and it may be open to permit the coal to pass into the hopper but may be closed to prevent further passage of the coal. As l will be seen from Fig. 3 the bottom wallsof the hopper merge into a feeder wheel .body or housing Il I8. This housing is accurately milled to accommodate the feeder wheel I5.

The feeder wheel is best shown in Fig. 5. it will be observed that this is made in the forni of a cylinder havingarcuate shaped recesses 28.

' arranged to enter a key-way 24.

The feeder body walls are provided with a bore having an axis coincident with that of the shaft 22. This bore is indicated at 25 in Fig. 4. Disposed in the bore I8 at each end is an adjustable member 26 having cone-shaped ends arranged to enter the recesses 2| of the feeder wheel. These members 26 have recesses in their ends to receive a felt washer 21, which is held in place by a metal washer 28. The feeder body has a slightly enlarged bore 29, arranged to receive a ball bearing set 30, the interior ring of which is fast on a reduced portion of the shaft 22, as shown on the drawings.

At one end of the feeder body housing is a plate 3 I, which secures the ball bearing sets or races in position. At the opposite .end the ball bearing arrangement is held in position by the casing 32 which contains the driving mechanism for the shaft 22. This consists of a gear 33, which is mounted on a hub 34. The latter is riveted to a sleeve 35 which passes through the outer wall of the casing and which is held on the shaft by means of a collar 36, and set screw 31. The hub 34 and the sleeve 35 are loosely mounted on the shaft. A pin 38 passes through the sleeve and through the shaft 22 to connect the parts together. This pin is made of material which will transmit motion from the gear to the shaft under normal conditions, but if a hard substance should fall into the hopper, thus causing the binding of the feeder wheel, then the pin 38 will shear off, thus protecting the parts from breakage. A worm 39 is disposed on a shaft 40 and actuates the gear 33. As will be seen from Figs. 1 and 3, the shaft 40 bears on its end a pulley 4I, with a V-shaped periphery.

Referring now particularly to Figure l it will be noted that the shaft 40 is connected by a belt 42 with a pulley 43 on the shaft 44 of an electric motor 45. The latter is preferably held in position by means of a bracket 46 carried by the hopper member IIa.

At present motorized machines of this type are driven by constant speed alternating current motors. It is, however,l desirable to change the speed of the feeder Wheel and of the air feeding means without changing the speed of the motor. To this end I have arranged the pulleys 4I and 43. In Fig. 6 the pulley 43 is shown as consisting of two parts having their edges inclined to form the groove in which the belt runs. 'I'he main body portion has a hub 43a which is threaded at 43h to receive the threaded portion 43c of the movable side 43d. Channels 43e are provided at spaced intervals around the center, there being four in the present instance as shown in Fig. 7. A set screw 43f is provided and by withdrawing the set screw the portion 43e may be turned to a position at right angles, or degrees or 270 degrees or more and the set screw can be put in the amines corresponding slot 33e to hold the movable portion in xed relation to the main body portion.

In the position shown in Fig. 6. the maximum speed would be delivered to the shaft 40 through the pulley 4l. When it is desired to decrease this 5 speed the set screw may he removed, the hub 43e turned and the set screw replaced whereupon the belt 48 will come nearer the central axis of the wheel, thus decreasing the speed. The motor 55 may be adjusted in any suitable manner so as to take up the difference inlength of the belt.

Referring to Fig. 4 it will be noted that the end of the shaft 22 is keyed to an eccentric 41 which is connected by ball bearings with an arm 48. 'I'he latter is pivotally secured to an arm 48 journalled on the shaft I2 bearing the ratchet wheel I4. A spring-actuated pawl 58 is arranged to engage the teeth of the ratchet so as to cause a slight movement of the shaft I2r for every revolution of the eccentric. Thus, the agitators I3 will be moved slightly for each revolution of the shaft thus tending to keep the coal in loose condition for feeding into the hopper.

In Fig. 3 it will be seen that the shaft 40 is connected by a coupling 5I with an air pump 52 having an intake 53, see Fig. 4. A pipe 54 leads from the air pumpand communicates with a pipe 55, see Figs. 1 and 4. The latter is in communica.- tion with the hopper for permitting air to enter therein. In Fig. 8 I have shown the preferred 80 means of introducing this air. 56 indicates a branch pipe from the air pipe 55 which enters a casing 51 secured in an opening in the wall I5 of the hopper. This casing is provided with an opening covered with air filter cloth 58 held in 3 8 position by a copper screen 59 against which a ring 50 is placed. This arrangement provides for admitting the air which will pass through the air filter cloth and through the screen, but will prevent the coal from getting into the air pipe.

As will be seen from Fig. 4 these openings are provided at various points in the walls of the hopper and communicate with the pipe 55 which is in turn connected with the source of air pressure, as previously stated.

Below the feeder wheel I9 is a discharge passage BI which leads into a tube 62. Disposed in this tube is a Venturi arrangement consisting of slidable members 63 and 64. A pipe 65 communicates with a fan 56, which is driven by a motor 61.

From the foreging description of the various parts, the operation thereof may be readily understood. The pulverized coal is fed into the chute I0 and lls the bunker II. As stated, the 55 agitators I3 and the feeder wheel are driven by the motor and the connections between the pulleys 43, 4I and the shaft 40. The coal in the hopper is caught by the pockets or recesses in the feeder wheel and is delivered to the discharge passage 6I. It will be noted that because of the offset position of the pockets one pocket at one end will deliver a measured quantity and then the pocket at the other end will deliver a measured quantity so that for one revolution of plates may be adjusted so that their lower edges 7|.

will afford the proper clearance for the efiicient working of the machine. The members 26 may be adjusted by means of bolts 26a which pass through the wall of the housing. These bolts slide in slots 2Gb so that by loosening them the members 28 may be moved toward or away from the conical walls of the wheel I9 and may be then secured in adjusted position. This arrangement provides for the delivery of the coal without any danger of the coal passing between the wheel and the conical shaped surfaces at the ends thereof. It will be observed that the coal rests partly on the surface of the wheel and partly on the conical surfaces of the members 28. This tends to provide for an efiicient scouring of the surface so that the coal will not cling to the wheel, but will be dumped therefrom to leave the wheel clean.

When it is desirable to speed the feeding up or to slow it up it may be done by means of the variable speed pulley in Fig. 6, as described, and this lends to the adjustability of the device so that the best results are obtained with a minimum expenditure of fuel.

The paddles or agitators I3 are turned slightly, as stated, to keep the coal in the bunker in a loose condition. In the hopper itself, however, this condition is maintained by the admission of air as stated, and it is this feature which tends to render this device highly enective.

An imp ortant feature of this invention in connection with the aeration of the coal in the hopper, is that the filter cloth and screen shown in Fig. 8 has a double function. Attention has been called to the fact that it permits air to enter the hopper while keeping the coal from entering the air pipe It. It also tends to prevent the forcing of the coal away from the point where the air comes in. since the air is distributed over a larger area and the screen tends to prevent any blast which might cause the coal to be blown away from the end of the pipe, thus creating a path of least resistance for the air which might escape instead of penetrating the body of the coal. With the arrangement shown in Fig. 6 the air penetrates the body of coal, but does not force it away from the air entrance point.

'Ihe pulley l1, see Fig. l, may be a variable speed pulley like the pulley 4I. Thus the fan 0l may be driven at a greater or less speed and may deliver more or less air, as desired. With this arrangement it will be observed that the amount of air supplied to the venturi may be regulated independently of the amount of coal or by means of variable speed pulley Il, the amount of coal delivered in a given time may be regulated independently of the amount of air supplied the venturi.

I claim:

1. In a device for feeding powdered coal, a hopper provided with a plurality of air inlets, a source of air pressure, pipes connecting said air pressure source with each of said inlets, a illter cloth disposed over each inlet, and a metal screen backing disposed adjacent to the filter cloth whereby air passing through the inlet is distributed in various directions and the powdered coal is prevented from entering the inlet.

2. In a device for feeding powdered coal, a hopper provided with a plurality of air inlets, a source of air pressure, pipes connecting said air pressure source with each of said inlets, and a. filter cloth disposed over each inlet of such density as to prevent a blast of air from entering through the inlet while permitting the `air to. slowly enter, thus equalizing the pressure on the other inlets.

3. In a device for feeding powdered coal, a hopper, a cylindrical feeder wheel having recesses on its periphery, certain of said recesses extending to one end of the wheel and the other recesses extending to the other end of the wheel, said wheel having a conical recess in each end, a stationary cone-shaped member arranged to enter each of said recesses, a portion of the surface of said stationary cone-shaped members constituting, together with the recesses in the ends of the feeder wheel, pockets for feeding the coal.

4. In a device for feeding powdered Ycoal, a hopper, a feeder wheel housing having a cylindrical bore, a feeder wheel having a diameter the same as that of the bore, cylindrical adjusting members at each end of said feeder wheel disposed in the bore and having cone-shaped ends extending toward one another, said feeder wheel having cone-shaped recesses on its ends arranged to receive the cone-shaped members, a shaft disposed centrally of the feeder wheel and the bore for mounting the feeder wheel for revolution, and removable means at the ends of said adjusting members for permitting the assembled shaft. feeder wheel and adjusting members to be removed through the bore.

5. In a device for feeding powdered coal, a hopper, a feeder wheel disposed at the bottom thereof, said hopper having slots in its side walls,

slidable plates disposed on the inner` walls of the 5 hopper, and movable toward and away from the feeder wheel, bolts secured to said plates and extending through said slots, washers for said bolts on the outside of said hopper, and nuts on said bolts for holding said plates in adjusted posiu tion.

MANUEL YOSS.

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