US2178360A - Coal feeding device for furnaces - Google Patents

Description

5 Sheets-Sheet l G. A. KOHOUT COAL FEEDING DEVICE FOR FURNACES Filed March 6,

[rave/7.507 66010 fife/20mg Oct. 31, 1939.

- Oct. 31, 1939. G. A. KOHOUT COAL FEEDING DEVICE FOR FURNACES Filed March 6, 1936 5 Sheets-Sheet 2 Oct. 31, 1939. e. A. KOHOUT COAL FEEDING DEVICE FOR FURNACES Oct. 31, 1939. G. A. KOHOUT COAL FEEDING DEVICE FOR FURNACES Filed March 6, 1936 5 Sheets-Sheet 4 Oct. 31, 1939. e. A. KOHOUT COAL FEEDING DEVICE FOR FURNACES 5 Sheets-Sheet 5 Filed March 6, 1936 [wen/0r 1 Gen/ye Q. [(050241 Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE COAL FEEDING DEVICE FOR. FURNACES George A. Kohout, Chicago, Ill. Application March 6, 1936, Serial No. 67,471 3 Claims. (Cl. 110-110) This invention'relates to coal feeding devices for furnaces and particularly to such feeding devices as are adapted to feed the fuel into the furnace and to distribute the same over the grate in the furnace while it is falling.

In my prior Patent No. 1,698,135, a method of feeding fuel is disclosed which consists in the spreading of the fuel over the furnace grate by striking it with a fluid blast while falling.

The present invention is an improvement over the device disclosed and claimed in the aforesaid patent in that it provides a simplified and more effective method of supplying the coal to the furnace and furthermore takes advantage of certain characteristics of a screw type of fuel feeding device to facilitate the spread of fuel over the furnace grates.

The invention further includes a novel structure of fuel feeding device whereby the fuel is not only advanced into the furnace by means of the fluid blast but has imparted thereto a forward momentum which aids the fuel blast in distributing the particles farther into the furnace chamber. 1 v

The invention contemplates also the provision in a fuel feeding device of this character of a novel hopper structure which cooperates with the particular fuel feeding device to provide for ready accessibility to all the parts of the mechanism.

It is a further purpose of the invention to provide a fuel feeding device wherein the parts "are adequately protected from the dust and coal par ticles and are also so contained as to prevent,

to a great extent, danger of accident to the operators attending the furnace.

More specifically, the invention contemplates the provision of a fuel feeding device having a hopper which can be opened up to provide ready access to the bottom thereof in combination with fuel feeding screws operating in the hopper in timed relation to each other to advance fuel to an inclined inlet opening to the furnace where I the fuel is struck by a fluid blast for the purpose of scattering it over the grates of the fire box of the furnace.

Other and more specific objects and advantages of the invention will appear as the description proceeds in connection with the accompanying drawings. It is to be understood, however, that the drawings and description are illustrative only and are not to be taken as limiting the invention except in so far as it is limited by the claims. In the drawings- Fig. 1 is a vertical section in part diagrammatic and taken longitudinally of a furnace to which the fuel feeding device has been applied;

Fig. 2 is a front elevation of the fuel feeding device with the front cover therefor opened up; 5

Fig. 3 is a plan section showing the fuel feeding device as mounted upon the furnace;

Fig. 4 is an enlarged section taken on the line [-4 of Fig. 2;

Fig. 5 is an enlarged sectional view taken on 10 the line 5-5 of Fig. 2;

Fig. 6 is a diagrammatic perspective view of the fuel-feeding device.illustrating the manner in which it is protected;

Fig. 7 is a sectional view taken substantially 15 on the line 11 of Fig. 2; Fig. 8 is an enlarged sectional view through the driving mechanism of a fuel .feeding unit;

Fig. 9 is a front elevational view of driving means for the feeding unit; and 20 Fig. 10 is a view on the line l0|ll of Fig. 1. Referring now in detail to the drawings, I have shown the invention as applied to a furnace having a fire box I0 beneath a boiler II. Within the fire box It) there is provided a grate l2 which 25 separates the fire box combustionzone from an ash pit I3. The furnace is provided at its front with one or more lower doors such as ll for access to the ash pit and with one or more over fire doors l5 which provide access to the fire box 30 lll'above the grates l2. The present invention concerns itself with mechanism for delivering fuel into the flre box l0 and spreading the fuel as it is delivered over the grates l2.

At the front of the furnace there is usually 35 provided a metal facing or covering I 8 in which the doors such as M and iii are mounted. Ad-

iacent to this metal facing and above the doors [5, I .mount a channel iron I!) which, as it is shown in cross section in Fig. 4, has a flange 20 that is secured directlyto the facing I8, as for example by suitable bolts 2|. 'I'he channel iron l9 also has a vertical portion 22 turned down at its outer edge, and at the lower edge of the portion 22 the channel iron is again turned out- 45 wardly as indicated at 23. The channel iron is supported at its opposite ends by a pair of legs 24 and 25 which legs are bolted preferably to the portion 22 of the channel iron. This channel iron l9 forms a hopper bottom and a mount- 50 ing portion for the fuel feeding mechanism as well.

Bolted to the portion 22 of the channel iron I9 is a horizontally running plate 26 which 'projects up above the channel iron. At the upper 65 edge of the plate 26, there is hinged a plate 21 which forms an upward extension for a front wall of the fuel hopper. At the left hand end of the fuel hopper, a plate 28 is mounted. This plate is secured to the facing l8 by a suitable angle bar 29 fastened by screws both to the plate 28 and the facing iii. A second angle bar 36 is secured at the forward edge of the plate 28 and forms a shoulder against which the sloping front plate 21 rests when in its raised position. A second plate 3| is secured in position at the right hand side of the fuel feeding device by angle bars 32 and 33. The angle bar 33 operates in the same manner as the angle bar 30 to provide a stop for the front plate 21.

The front of the drive mechanism for the fuel feeding device is closed below the plate 21 by a hinged front cover section 34 which extends across the front of the furnace and is'hinged to the horizontally projecting portion 23 of the channel iron IS. The plate 21 carries an inverted V-shaped strip 35 to which the section 34 may be secured by suitable wing nuts such as 36 and 31 engaging bolts which project from the strip 35. Similarly, wing nuts 38 and 39 are utilized to secure the plate 21 in raised position. The section 34 does not extend all the way to the right hand end of the furnace, but is supplemented by a separate section 40 which is hinged to the portion 23 and is secured by a suitable locking device 4| to a front plate 42 which extends from the end plate 3| of the hopper outwardly to the end of the fuel feeding casing.

The front plate 42 is part of an end housing 43 which extends down over the end of the channel iron I8 as shown .best in Fig. 6. The end housing 43 extends vertically substantially to the top of the hopper end plate 3| and has a top portion 44 (seeFigs. 6 and 7) that extends over to meet the hopper end plate 3|. A door 45 is provided in the end of the housing 43. This door is provided with a suitable latch mechanism indicated at 46. Also, the housing 43 hasa top door 41. Thus access is readily obtained from three sides into the interior of the housing 43. The door 40 may be opened for access at the front. The door 45 may be opened for access at the end, and the door 41 may be opened for access at the top.

From the above description, it is believed to be evident that the entire fuel feeding mechanism is fully housed and protected. The housing furthermore forms a part of the hopper structure, the plate 21 being a cover for the driving means for the fuel feeding mechanism, as will be more clearly explained hereinafter. Also, the housing 43. cooperates with 'the end plate 3| to enclose a damper regulator mechanism 48 and a suitable drive mechanism 49 for the fuel feeding device. As shown best in Fig. 4, the hinged section 34 may be let down to permit dropping the front plate 21 of the hopper whereby ready access is obtained to the fuel feeding parts that are exposed in the hopper.

The mounting of the fuel feeding mechanism upon the channel iron i9 and upon the plate 26 will now be described. Referring to Figs. 3 and 4 in particular, it will be observed that there are a plurality of pairs of brackets 58 and 5| spaced lengthwise of the channel iron l9. Each of these brackets is bolted by means of a suitable bolt 52 to the front plate 26, then they are bolted by means of a pair of bolts 53 and 54 to the channel iron l9. These brackets serve also to secure a plurality of feed screw housings 55, 66, and 51 to the channel iron |9. The front wall of the furnace is provided with a plurality of inlet openings into which the feed screw housings 55, 56, and 51 extend. The facing|8 is utilized as one wall of the hopper and has openings cut therein through which the housings 55, 56, and 51 extend. As a matter of strengthening the structure, an angle iron 58 may be provided opposite the flange 20 of channel iron Hi to aid in supporting the fuel feeding mechanism. The several brackets and 5| thus serve to unite the front plate 26 with the channel iron i9 and the housings 55, 56, and 51 in such a manner as to produce a substantially rigid assembly. This is highly desirable in order that no difliculties will be encountered due to the housings being out of line with the front plate 26 which carries a feed screw operating mechanism for turning feed screws in the housings 55, 56, and 51.

The feed screw mechanism constitutes a plurality of feed screws 59, 68, and BI which feed screws overlie forwardly extending portions of the housings 55, 56, and 51 that are held down by the brackets 50 and 5|. Each feed screw is provided with a polygonal socket at 62 (see Fig. 8) which socket receives a polygonal head 63 on a drive shaft 64. A pin-65 is utilized to secure the feed screw to its drive shaft.

The drive shaft 64 is supported on a bearing block 66 which is bolted by suitable screw bolts 61 to the front plate 26. The shaft 64 has an enlarged bearing portion 68 that seats in a bear ing 69 carried by the block 66. Suitable oil grooves 10 and 1| are provided in the bearing 69. The shaft 64 projects beyond the block 66 and is provided with a sleeve 12 on which there is mounted a rocker arm 13. The rocker arm 13 is adapted to be rocked to and fro by a suitable power mechanism to be hereinafter described. This arm has a hub portion 14 rotatable on the sleeve 12. The hub portion 14 carries a projection 15. A pivot pin 16 is bolted to the projection 15 by a screw threaded extension 11 thereof, and this pivot pin carries a pawl 18.

A ratchet wheel 19 fits on the shaft 64 and is connected thereto by a connecting block 60 which is rigidly 'securedto the shaft 64 by a shear pin 8| that may be sheared off in event of excessive strain. The block is connected to the-ratchet wheel 19 by a second 'pin 82. It is understood, of course, that the pin 82 which connects the block 88 and the ratchet wheel 19 is stronger than the shear pin 8| so that inpthe event of excessive strain the point of breakage would be at the shear pin 8|.

The pawl 18 is controlled in its engagement with the ratchet wheel 19 by means of a shield which comprises a plate 83 pivoted on the shaft 64 between the ratchet wheel 19 and the hub 14. This shield has a flange 84 which projects over the ratchet wheel 19 so as to prevent the pawl' 18 from contacting the teeth of the ratchet wheel. The shield is adjustable to expose different numbers of the ratchet wheel teeth.to the action of the pawl 18 by rotation of the shield about the shaft 64. For this purpose, the plate 83 is notched at 85 about its periphery and a pin 86 is mounted on the bearing block 66. This pin 86 is adapted to seat in any desired one of the notches 65 and to hold the shield flange 84 in any desired position with respect toithe pawl 18.

The foregoing description, while confined to one drive unit only, applies to the several drive units for driving the three feed screws 59, 66, and 6|. For convenience in tracing the numbering,

the drive units will be referred to as 59', 60', and SI It will be noted, by reference to Fig. 2, that the pawl 18 for the drive unit 60' is pointed in the opposite direction to the pawls 18 for the drive units 59 and 6|. Similarly, the teeth of the ratchet wheelof the drive, unit 60 are reversed so that, when rocking movement is imparted to the respective arms 13 of the drive units, the drive, unit 60' will operate to turn its screw 60 in the opposite direction to the rotation of the screws 59 and BI. The power required to turn the screw 60 is also required during the time when the screws 59 and 6| are at rest.

The several arms 13 are connected to a driving bar 81 so that they are rocked in unison by reciprocation of this bar. The connection of each arm 13 to the drive bar 81 is made by means of a bolt 80 and a bearing sleeve 89, together with a washer 90. This construction is best shown in Fig. 8.- The bar 81 has a link 9| pivoted thereto, and this link is connected to the lower end of a rocker arm 92 by means of a pin and slot con- Fig. 2) that is mounted on A link 91 connects the upper end of the rocker arm 92 with a pin 98 on a disk 99 that is rotated nection consisting of a slot 93 in the arm 92' and a bearing pin 94 for the link 9| which bearing pin can be adjusted to vary the length of stroke given to the bar 81 for any fixed angular movement of the rocker arm 92. The rocker arm 92 is pivoted on a standard 95 that is carried by a plate 96 (see the channel iron I9.

by the drive unit 49.

The drive unit 49 comprises a reduction gear of any well'known type and received its power from a drive pulley I00. The drive pulley I is driven by a belt IOI from a pulley I02 on a motor I03. The motor I03 is suspended from the channel iron I9 in the manner shown in Fig. 7 by means of a bracket I04. The motor has a base I06 that is hinged to the bracket I04 and adjustably connected to the part 23 of channel iron I9 by a bolt I01 and suitable lock nuts I08 and I09. By means of the bolt can be raised and lowered to obtain the proper tension upon the belt IOI. The reduction gear unit 49 is supported upon a plate H0 which is mounted on the channel iron I9.

The drive unit 49 also drives a second reduction gear unit III by means of a shaft H2, and this reduction gear unit III operates a disk H3 to which a damper control link I I4 is eccentrically pivoted. The link I I4 is the means for operating a damper regulator 48 which is of the type disclosed in my prior Patent No. 1,875,616. The damper regulating mechanism indicated generally by the numeral 48 is adapted to be connected bya flexible cable or similar arrangement to a damper in the furnace stack. As shown in my prior patent just referred to, this connection is made to the member 48' of the damper regulator.

The operation of the damper regulator 48 is the same as that disclosed in the above mentioned patent. Therefore, the --details of its operation will not be described in the present application.

The bar 81 in addition to-operating the several feed screws is also utilized to operate a shaker device for shaking down the coal in the fuel hopper. Referring now to Figs. 2 and 5 in particular, it will be noted that the bar 81 has a pin H5 mounted thereon between its connection to the units 59' and 60'. This pin is adapted to engage a forked arm H6 that is secured to a shaft H1 by a shear pin H8. The shaft H1 is mounted in a bearing H9 that is bolted to the .the other.

I01. the motor plate 26. The bearing II9is an elongated sleeve bearing which has a flange I through which suitable screw bolts I2I are passed to mount. the bearing upon the plate 26. Within the hopper over the channel iron hub I22 secured thereto by a pin I23. The hub I22 has an annular flange I24 thereon. A bar I25 extends lengthwise of the hopper and is secured to the flange I24 by a rod I26 whichis pivoted in a bearing member I21 seated in an opening in the flange I24. Suitable collars I29 and I30 are fixed on the rod I28 to hold the bar I25 in position, and the rod I26 has the oppositely projecting extensions I3I and I32 that are adapted to move to and fro in the coal in the hopper so as to prevent the same from clogging. The bar I25 is also supported between the drive units 60' and SI by a second shaft I33 that is supported by a bearing block I34 also secured by suitable screw bolts to the plate 26. The shaft I33 carries a disk I35 that is connected to the bar I25 by a rod I36 in the same manner as rod I25 connects the flange I24 to the bar I25. The opposite ends of the bar I25 have triangular loops I 31 and I38 therein for shaking the coal at the ends of the hopper.

The operation of the coal shaking mechanism is as follows: The bar 81 in reciprocating causes the pin H5 to strike first one side and then the other of the forked end of the arm H6 so as to move this arm first in one direction and then in This motion is communicated to the bar I25 and its rods I26 and I36 by means of the shaft H1 so as to oscillate the bar I 25 in the hopper.

Referring now to Figs. 3 and 4 in particular, the mechanism whereby the fuel is introduced into the fire box through the housings 55, 58, and 51 will be described. Each of these housings is preferably cast with a bottom extension I 40 that projects over the channel iron I9 and beneat the screws so that it may be secured flrmly in place by means of the brackets and 5|. From the face plate I8 toward the fire box, the housing has a tubular portion I4! into which the feed screw extends. and this tubular portion may desirably have a rounded or semi' tubular portion MI is partly closed by a wall I45, and this wall carries a refractory supporting bracket I 46 cast integral therewith.

Beneath each housing 55, 56, and 51, there is provided a second casting I41 which casting rests upon refractory material I48 at the front of the fire box and supports the tubular portion I II of each housing. This casting I41 is hollow. as indicated in the sectional view in Fig. 1. At the fire box end of the casting M1, the top thereof is stopped at the terminal edge i 32 of the tubular portion I4I of the housing and slopes downwardly as indicated at I49 to provide a sloping shelf down which the fuel rolls as it is fed through the housing by the feed screw. The slope of the face I49 may, of course, be varied within rea sonable limits, but it preferably makes an angle of about 4 5 to the horizontal. The casting I41 has a flat slit opening I50 at the lower edge of the sloping face I49, and directly beneath this opening there is inserted a cast iron plate I5I that may be adjusted in and out and which serves as a landing where the coal particles strike I9, the shaft H1 has a may be from and rebound after they roll down the sloping face I.

A fluid injector I52 is mounted in the interior of the casting I41. The details of this injector are more clearly explained in my copending application Serial No. 67,470, filed March 6, 1936. The function of the device I52, however, is to direct a fluid blast through the opening I50 so as to strike the coal which has already been given a forward impetus by its rolling down the sloping face 45 and bounding oif of the plate I51. The effect of the fluid blast striking the moving particles of fuel is to give them more speed in a horizontal direction soas to drive them out into the fire box and to drive the fine particles which are more susceptible to the fiuid blasts farther out into the fire box than the coarser particles are driven. The blast is powerful enough to drive most of the dust and real fine particles out into the fire box without their striking the plate I5I. However, the larger particles have enough momentum from rolling down the inclined face 9 to cause them to engage the plate l5l and rebound upwardly. By this action of the larger particles, they are held under the influence of the fluid blast long enough to give them a substantial throw into the fire box.

grates is'not a complete separation with all of the coarser particles closer to the front of the fire box. In fact, the particles which are just too fine to gain enough momentum to strike the plate I5l often times fall to the grate more closely to the front of the furnace than the larger par ticles which rebound off of the plate I5I. Thus a resultant intermingling of coarse and fine particles occurs over most of the grate surface. At the extreme front end of the grates where burning of the fuel is naturally at a low rate, because of the proximity of the fuel to the front structure of the fire box, very little fuel is deposited.

-In order to protect the housings such as 55, 55, and 51 from the heat within the fire box, the fuel outlet I is shielded by means of a special refractory tile I53 that is provided with a T slot adapted to receive the bracket I46 on the end of the housing. A pair of side tile I54 and I55 is mounted alongside the refractory tile I53, and these tile, as shown by Fig. l and Fig. 3 extend back over at least half the length of the tubular portion Ill of each housing. A cap tile I51 covers the tile I51.

The fluid blast supplied by the member I52 any suitable source. For example, I have shown a steam supply pipe I56 (see Fig. 1) leading to a nozzle I51 that is directed into the member I52 so as to act as an injector and to draw in a substantial blast of air mixed with steam which blast is then driven through the opening I5 and utilized to spread the coal in the fire box.

From the above description, it is believed that the construction and operation of this de- The resultant distribution of the fuel over the vice will be readily apparent to those skilled in this art.

Having thus described one specific form of my invention, what I claim as new and desire to secure by Letters Patent is:

1. A coal feeding device for furnaces comprising in combinaiton, a fire box having a grate therein and having a front wall provided with a fuel inlet to the front of the fire box, a feed screw housing extending into and communicating with said inlet,'a hopper outside the fire box at the front thereof and having an opening into said housing, a feed screw in said hopper and extending into said housing, means to rotate said screw and thereby advance fuel from said hopper into the housing, said hopper having a front wall extending over the screw rotating means, said front wall being pivotally mounted at its lower edge and foldable down over the screw rotating means to provide ready access to the screw in the hopper, a support for said hopper beneath said screw means mounting said screw, rotating means on said support, a cover for the front of said screw rotating means hinged at its lower edge to said support, and means detachably securing said cover at its upper edge to the front wall of the hopper.

2. A coal feeding device for furnaces comprising in combination, a fire box having a front wall provided with a plurality of fuel inlets to the fire box, feed screw housings extending into and communicating with said inlets, a hopper in front of said wall having openings into said housings, a channel iron fixed to the front wall and providing a support for said hopper, feed screws in said hopper and projecting into said housings, means to rotate said feed screws, a plate fixed tosaid channel iron, said screw rotating means being mounted to said channel iron by said plate, brackets connecting said housings and said plate to said channel iron, the front wall of said hopper being hinged to said plate, and a front cover for the screw rotating means hinged to said channel iron and having an individual door therein in front of each of said feed screws.

3. A coal feeding device for furnaces having a fire box having a grate therein and having a front wall provided with a plurality of fuel inlets to the front of the fire box, said coal feeding device comprising a hopper at the front of the fire box, a support for said hopper adapted to be secured to sa d front wall, a plurality of feed screw housings extending into said fuel inlets and communicating therewith, feed screws in said hopper and extending into said housings, screw rotating means carried by said support for advancing fuel from the hopper into said housings', said hopper having a front wall extending over the screw rotating means, and said front wall being pivotally mounted at its lower edge and foldable down over the screw rotating means to provide ready access to the screws in the hopper.

GEORGE A. KOHOUT.

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