US2808214A - Wet material bridging alleviator - Google Patents

Description

Oct. 1, 1957 F. H. NEELY 2308214 wET-MATERIAL .BRIDGING ALLEVIATOR Filed Jan. 6, 1956 I w v INVENTOR Foreslv 1-1. Neelq.

ATTORNEY w illustrating one example of providing United States PatentO WET MATERIA BRIDGINGALLEVIATOR Forest H. Neely, Philadelphia, Pa., assignor to Poor & Company, Chicago, 111., a corporation of Delaware Application January 6, 1956, Serial No. 557,686 2 Claims. (Cl. 241-186) This invention relates to reduction mills, such as reversible hammer mills or reversible impact mills, and more particularly to an arrangement for automatically avoiding the accumulation of wet and sticky material which has a tendency to bridge orblock the throat of the mill as a result of the centrifugal force of the rotating hammers.

It is customary in the crushing of materials, for example coal, to add a small amount of medium or heavy residual fuel oil to the bulk material just prior to entering the mill. This additive plus the usual residual moisture makes the fine particles developed by the mill wet and sticky enough to cause bridging and packing in the throat of the feed chute, above the fixed breaker blocks at either side of the feed chute, depending on the direction of rotation of the mill. During a given period of operating time this bridging of the chute can so constrict the feeding of material to the mill that its capacity is materially reduced. With the present invention bridging is substantially eliminated to the point where no stoppage of the mill is required for manually breaking up the collected material.

Accordingly one of the objects of the present invention is to provide a pair of reciprocating breaker blocks at the inner end of the throat of the feed chute whose upper portions will cooperate with the feed chute to continuously break up the Wet and sticky material as it tends to cake, thereby avoiding the reduction of the area of the feed chute to permit free feeding of material, and returning the broken pieces of the cake to the crushing zone.

Further objects of the invention are to provide a novel mounting for the movable breaker blocks relative to the feed chute, and a simple and practical mechanism for alternately reciprocating the movable breaker blocks.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the same consists in the combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

In the drawings:

Fig. 1 is a fragmentary sectional view of a hammer mill illustrating the feed chute, the reciprocating breaker blocks and their relative positions with respect to the chute and fixed breaker blocks, the wet material buildup being shown in dotted lines.

Fig. 2 is a fragmentary elevation of a hammer mill power for causing the breaker blocks to reciprocate.

Similar reference characters designate corresponding parts, in the several figures of the drawing.

As will be observed from Fig. 1, there is shown a conventional reversible hammer mill A having a casing B and hammers R of any desired type and constituting a part of the rotor, which, as is well known, may operate either in a clockwise or a counterclockwise direction.

The casing B is provided with a feed chute C through which the material to be crushed is fed into the mill 2 a v and into the crushing zone of the' rotor circle. This feed chute has an outer portion 1 extending above the casing B and an inner lower portion 2 extending within the casing. Below the inner portion 2 of the feed chute are mounted movable breaker blocks 3 and 4. The upper ends of these breaker blocks are provided with recessed portions 3a and 4a whose lower ends are beveled and which recessed portions slidably engage the` outer surface of the inner end 2 of the chute so that the Shoulders 3b and 4b have a shearing action with respect to the buildup of the cake as indicated at x when the mill is rotating clockwise. w g

The body portions of the movable breaker blocks 3 and 4 are of generally arcuate formation and have the relativelyl flat ends 3c and 4c in relatively close transient proximity to adjacent edge portions of' the fixed breaker blocks 5 and 6 of the mill. I

Asv Will be seen from Fig. 1, thel breaker block 3 in its lowered position, that is, at the bottom of its down- `Ward stroke will have its shoulder 3b pulled away from the edge 2a of the chute and at the same time the end 3c will be below the impact surface of thefixed breaker block 5. Also, simultaneously the movable breaker block 4 will be in its uppermost position, whereby the upper shoulder 4b will substantially engage the lower edge 2b of the chute C to break up the cake x and the lower edge ofits substantially Vertical face 4c will be in substantial registry with the impact surface of the fixed breaker block 6.

The beveled portion of breaker blocks 5 and 6 adjacent to movable breaker blocks 3 and 4 should be low enough to allow for maximum adjustment for wear but to still serve as stops for any adjustment or downward movement beyond the maximum life of blocks 3 and 4 and to prevent blocks 3 and 4 from ever falling'into hammer circle.

The movable breaker blocks 3 and 4 are each provided on their rear sides with hanger portions 7 and 8 for receiving the lower end of a supporting link.

Since the supporting links and their means of operation are the same for both movable breaker blocks 3 and 4, a description of one link and its Operating means will sufi'ice for both. The lower ends 9 of each link fit into suitable eyes or recesses formed in the hanger portions 7 and 8. The shank portions 10 of each link may be provided with conventional means to adjust for wear and are pivotally 'suspendcd at 11 from a yoke or angular loop member 12.

Each yoke or loop 12 receives the cam 13 mounted on a related shaft 14. As will be seen from Fig. 2, each shaft 14 is appropriately journaled on the outer side of the casing B and the end of each shaft opposite the cam 13 is provided with a sprocket gear 15. At a suitable point on the casing B a driving motor M is mounted. This motor operates reduction gear in the housing M' thereby to supply power to shaft 16 which in turn carries sprocket gear 17. This sprocket gear, and the sprocket gears 15 have sheaved thereabout a ilexible driving element 18 preferably in the form of a chain.

When the mo'tor M drives the chain 18 the shafts 14 will continuously rotate and the cams thereon will move the yokes or loops 12 alternately upwardly and downwardly at approximately fifteen complete strokes per minute so that the Shoulders 3b and 4b of the movable breaker blocks 3 and 4 will have a shearing action with respect to the lower edge portions 2.a and 2b of the chute.

In the example shown, the mill may be assumed to operate in a clockwise direction and the cake Would tend to form at x but, because of the movement of movable breaker block 4 complete formation is avoided, and particles would be deflected downwardly as indicated at x'.

Thus, any tendency of wet and sticky material to cake or pack in the chute will be continuously broken up to fall back in the crushing zone andrthus besubjected to further action of the rotor harnmers. In this way the inner throat portion of the feed chute C will be kept clear of build-up -andthe millfcan operate'Vcontinuouslywat full 'capacity without shutdown "for, clearin'g :the cake'd matter away.

I'clairn:

1. 'A twet and sticky material fbridgingqalleviator :for reversible hammer-mills including azhammerfrotor,4 oper- 'ating between fixed breaker plates, comprisng, a'casing forl housing ythezhamnier rotor and`fixedbreaker plates, a vertically -di-sposed downwardly ;discharging :feed :chute extending exteriorly. and interiorl-y of the gcasing, Vfaz' pair of movable breaker =plates V each having: .theirlzuppert'portions slidably engaging the outer face of theiainteorly disposed portion of lthe `feed 'chute zandin-*sheari'ng i relationthereto and: their lower-portions dsposed in'f'transient proximity to lthe fixed bre'aker| ,.plates,:- links ffor'jsupport- -ingthe movable breaker platesya closedoloop connected with the upper end of eachlinkfshafts :mounted ratop'- piosite 'sides 'ofl the *feed chute',1a ycam on -onend-tofzeach shaftoperating in arelated-loop,-a5 sproeket'gearmounted on each shaft,'a-motor1having -a shaft and mountedrmn the casing, and flexible drivingl means ;sheaved vover :the -sprocket gears on'saidshafts -and;driven tlyfaI sprocket gear ;on the motor-shaft. o

2. 'A wet and'sticky material bridgin'g alleviator *for i reversible hammer mills including i a .hammer w rotor .operating between fixed breakerfplates and defining a hammer circle, comprising, a casing -for housing the hammer rotor and fixed breaker plates, a vertically disposed downwardly discharging feed chute extending'exteriorly and interiorly of the casing, a pair of vertically movable breaker plates each having arcutelbo'dies provided with recessed upper-ends-havng shoulders,-said upperfends slidably engaging'the'low'er en'd 'f 'the`feed"chute, the 'lower portions of -said1 bodies -adjacent the 'hammer vCircle-'having :"substantially :Vertical wllportionsinfttansient\proxiniity to the fixedbreaker plate, links forupportingthe movable breaker'plates and meansfofvertically reciprocating the links to cause thefmovabl'e breakerplates'lto move relative to the fixed breaker plates.

. References Cited in the file of this patent ;UNITED vs'T-A'mis yuiTENTs

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