US2174934A - Pulverizer mill - Google Patents

Description

Oct. 3, 1939.

H. R. COLLINS PULVERIZER MILL Filed Aug. 12, 1936 gwuc wbov P-Lp. COLLIN S arm Patented Oct. 3, 1939 UNITED STATES PULVERIZER MILL Harry 1:. Collins, Allentown, Pa.; May H. Collins administratrix of said Harry R. Collins, de-

ceased Application August '12, 1936, Serial No. 95,660

9 Claims.

This invention relates to pulverizer mills especially intended for the reduction of non-metallic materials, such as coal, limestones, and cement clinker, by either wet or dry grinding, and in its more specific aspects pertains to mills of the type in which the grinding assembly comprises an annular series of grinding elements, preferably balls, which cooperate with grinding surfaces, one of which is rotatably driven in a 10 horizontal plane to actuate the balls.

Among the objects of the present invention may be noted the provision of a mill of simple mechanical construction, in which the reduction of the material under treatment is accomplished in a single stage, the structure contemplating an arrangement in which a grinding assembly of the stated character and the driving mechanism therefor are symmetrically disposed about a vertical axis with the driving mechanism being positioned above the grinding assembly. Further,

the driving and grinding mechanisms are arranged as separate assemblies, independently supported and self-centering, with the contemplated arrangement permitting assembly, installation, and/or removal of the driving mechanism as a unit without disturbing the grinding assembly, which latter, upon removal of the driving mechanism as aforesaid, is readily accessible so that elements thereof subjected to wear may be expeditiously replaced when necessary,

The present invention further contemplates a pulverizer mill of the above character embodying a grinding assembly in which grinding pressures may be adjusted to the material under treatment in a simple manner and by readily accessible means, with provision being made for regulating the degree of fineness of the product to satisfy varying requirements.

Other objects will be in part obvious and in part hereinafter pointed out in connection with the following analysis of the invention, wherein is illustrated one embodiment of my invention in a detailed partial sectional elevation.

Referring tothe drawing, reference character Ill designates a generally cylindrical casing constituted by a lower casing section II, provided with an annular flange l2 which may serve as a bed plate for the apparatus, and an upper section l3. Between the casing sections I1 and l3.is arranged a main bearing support M, with bolts or equivalent securing means l5 removably securing bearing support l l to facing flanges of the aforesaid casing sections. The upper casingsec- 55 tion I3 is provided with a horizontal top plate I8 which serves to close. the topof the casing In as formed by the casing sections as aforesaid.

Arranged on the top plate is of casing section i3 and suitably secured thereto is a vertically disposed motor 2fifor the driving assembly, the motor shaft 2i of which extends through the top plate l8, and into the chamber or compartment form-ed by the casing section [3, its top plate l8, and the main bearing plate l4.

Motor shaft 25 carries a hardened steel pinion 10 22 which drives oppositely arranged idler gears 23, 24 carried by bearings on suitable vertical shafts 25, 2t, respectively, secured in the cover plate l8 of the top casing section. Idler gears 23, 2Q mesh with a ring gear 28 carried by a cir- 15 cular supporting plate 3f], the latter being secured as by bolts 3i to a flange formed on the upper end of a main driving shaft 32, the upper portion of which is circular in cross-section.

The main bearing plate I4 is provided with a 0 central elongated hub 33 disposed about the circular portion of the shaft 32, the hub being suitably recessed to receive the outer raceways of spaced roller bearings 34, 35, the inner raceways being carried by the main driving shaft 32 in the 5 main bearing plate M. A packing ring 36 operative between the end of the hub 33 and the driving shaft 32 serves. to exclude the entry of dust along the shaft and into the driving mechanism. The bearings 34, 35 are suitably lubricat- 30 ed as by grease injected through a bore (not shown) extending through the main bearing plate from a suitable source of supply.

The main bearing plate hub 33 extends upwardly above the top horizontal surface of the 5 main bearing plate I i, proper, and hence there is formed within the compartment which houses the drive assembly as aforesaid an annular well or reservoir adapted to contain a quantity of lubricating oil for the elements of the driving 40 assembly, such being supplied to the reservoir through a port 40 extending through the main bearing plate l i communicating with an oil supply line indicated at 4|.

The bottom plate of the ring gear 28 is provid- 45 ed with one or more apertures as at 42, and threaded into each of said apertures is a scoop pipe 43 which extends downwardly into the oil reservoir and below the level of the oil contained therein. Upon rotation of the ring gear 28 and its bottom plate, the open-ended scoop pipes 43 pick up oil contained in the reservoir and force it upwardly into a secondary oil reservoir constituting the zone of the motor shaft pinion 22, idler gears 23, 24, and gear surfaces of the ring gear 28, thus to lubricate the same.

Vertical shaft 25 on which idler gear 23 rotates extends through the top late I8 of casing section l3, and into a two-part housing 45 suitably secured to the casing top plate l8, the housing 45 containing driving elements for a rotating feed table 46.

The feed table drive as aforesaid preferably consists of a worm pinion 47 keyed or otherwise secured to the upper end of the vertical shaft 25, the pinion being in driving relation to a gear (not shown) arranged on a horizontal shaft 48 suitably journaled in the housing 45, and being provided also with a worm gear (not shown) in driving relation to a pinion 50 carried by a vertical feed table shaft 51. Idler shaft 25, the horizontal shaft 48, and the feed table shaft 5| are suitably mounted in bearings as illustrated, the arrangement being such that feed table 46 is driven from the motor shaft 2| through a gear train includ ing pinion 22, idler gear 23, pinions 41 and 55, and the gear surfaces of shaft 48.

To lubricate drive parts contained in housing 45, top plate 18 of the casing section l3 and the bottom wall of housing 45 are provided with a set of aligned apertures, and threaded into said apertures is a scoop pipe (shown in dotted lines) the lower end of which extends into the secondary reservoir formed by ring gear 28 and its bottom plate 36, and below the level of the idler gear 23 rotating on a fixed axis therein. Hence oil forced into the ring gear by scoop pipe 43 is in turn raised by scoop pipe 52 into the housing 45, and functions to lubricate the table drive elements therein contained.

The lower end or half of the main drive shaft 32 is, of square or other angular section and extends through a central opening in the hub 55 of a movable grinding ring 56, the opening in said hub being slightly larger than the shaft, so that the ring is permitted a limited free vertical as well as horizontal movement for the purpose of maintaining alignment due to possible inaccuracies in manufacture or normal wear of the grinding elements.

Preferably, the extreme lower end of the square portion of the main driving shaft 32 is formed circular and threaded, and a bottom horizontally extending disc 5! is threaded thereto. This disc is locked fast to the main driving shaft 32 as by cap bolts 58, and carries the compression bolts 60, the upper end of each of which engages against a spring head 6| with which engages one end of a compression spring 62, the other ends of which extend into downwardly opening pockets the rim 65 to receive the circumferentially channeled raceway 66, preferably welded to the ring, on which is supported an annular series of grinding balls 61. The top surfaces of the balls 61 engage in a circumferentially channeled or grooved upper raceway 68 secured as by welding to the under face of a fixed grinding ring it, the

latter being supported on an inwardly directed ledge ll formed on the inner surface of the casing section II.

The curvature of the channels or grooves of the movable and fixed grinding rings 56, 16, respectively, is substantially that of the grinding balls El, and it will be noted that the channel of the fixed ring is directly above the channel of the movable ring.

Fixed ring holding bolts 15 extend through suitable bosses 16 formed in the wall of easing section H and are disposed to exert downward thrust on the fixed ring, whereby to hold it seated on the supporting ledge H. Upon unthreading of said holding bolts 15, fixed ring raising bolts ll may be manipulated in such manner as to unseat the fixed ring from its supporting ledge, whereupon it may be bodily raised for removal from the mill casing.

The upper surface of the fixed grinding ring 16 is substantially conical as at 86, whereby to direct material spouted into the casing through the inlet opening 81 thereof from the hopper 82 and feed table 46 to be directed inwardly against the inclined intermediate portion of the movable grinding ring 56. Thus, material falling on the inclined upper surface of the fixed ring is directed inwardly and thence downwardly into the annular space between the cylindrical portion of the movable grinding ring and the inner side of the annular series of grinding balls 67, the flow of the material being thence outwardly through the series of balls.

Fixed to the outer peripheral edge of the movable grinding ring 56 is an adjustable height dam 35, to the upper portion of which is secured a screen 86, with the dam functioning to control discharge of pulverized material through the screen until it has been reduced to the desired degree of fineness as determined by the screen openings. Pulverized material passing through the screen drops into the annular space between the outer side of the dam 85 and the inner wall of the casing, whereupon it is picked up by the air entering the lower portion of the casing through air inlet openings 88 to the exhaust fan 96 se cured to the bottom of the casing, and after passing through grating 81 enters the fan and is forwardly thereby. The fan 96 is driven by a shaft 9| which passes upwardly through a bore 92 in the main driving shaft 32, and is secured at its upper end to the hub of the driving pinion 22. The lower end of the shaft 9| is supported for rotation in a bearing (not shown) formed in the lower fan section. It will thus be seen that the motor 26 drives the fan 96 at full load speed, Whereas the grinding balls 67 are driven circumferentially of the mill at a reduced speed which preferably corresponds to gravity fall of the material, by means of the speed reducing effect of the driving mechanism as aforesaid.

It will be understood that a slurry pump may be substituted for the fan 96 when wet grinding is contemplated.

With the aforesaid arrangement of grinding assembly, grinding pressures may be adjusted to the material under treatment by proper manipulation of the compression bolts 60, thereby to adjust the pressure on the springs 62 to that desired. The compression springs transmit an upward resilient thrust to the grinding balls through the medium of the rotating grinding ring, this by reason of the fact that the outer or rim portion of the said ring is disposed below the fixed grinding ring.

in a pulverizer mill according to the foregoing design, the symmetrically disposed driving and grinding mechanisms are substantially separate assemblies. Thus, by removal of the holding bolts l5, top casing section l3 may be removed, thus to permit access to the driving mechanism supported by the main bearing plate I4. Further, by disconnecting the spring holding disc 51 from the drive shaft 32 and the substitution of temporary holding means for the rotating ring 56, the main bearing plate l4 and the driving assembly carried thereby may be raised as a unit from the casing, thus to permit access to the grinding assembly or to permit removal of the latter for the purpose of replacing worn parts.

As many changes could be made in carrying out the above construction, without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A pulverizer mill comprising, in combination, a rotating grinding ring having on its under side a plurality of spring seats and a grinding surface on its upper side, an annular series of grinding elements supported on the grinding surface, a non-rotary grinding ring above the grinding elements and provided on its under side with a grinding surface, a drive shaft supported from above the grinding rings and extending downwardly through and below a portion of the rotating grinding ring and having a driving connection therewith, a spring-carrying element secured adjacent the lower end of the drive shaft, and compression springs operative between the spring seats and the spring-carrying element for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for applying grinding pressure on the grinding elements.

2. A pulverizer -mill comprising, in combination, a rotating grinding ring having on its under side a plurality of spring seats and a grinding surface on its upper side, an annular series of grinding elements supported on the grinding surface, a non-rotary grinding ring above the grinding elements and provided on its under side with a grinding surface, a drive shaft supported from above the grinding rings and extending downwardly through and below a portion of the rotating grinding ring and having a driving connection therewith, a spring-carrying element secured adjacent the lower end of the drive shaft, compression springs operative between the spring seats and the spring-carrying element for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for applying grinding pressure on the grinding elements, and spring adjusting means carried by the spring-carrying element.

3. A pulverizer mill comprising, in combination, a rotating grinding ring having a hub portion, an intermediate portion, and a rim portion, the intermediate portion being provided on its under side with a plurality of spring seats, and the rim portion being provided on its upper side with a. grinding surface, an annular series of grinding elements supported on the surface, a non-rotary grinding ring arranged above the rim portion and provided on its under side with a grinding surface, a drive shaft supported from above the grinding rings and extending downwardly through and below the hub portion .of the rotating ring and having a driving connection therewith, a spring-carrying collar secured adjacent the end of the drive shaft and being disposed beneath the spring seats, and compression springs operative between the spring seats and the spring-carrying element for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for applying grinding pressure on the grinding elements.

4. A pulverizer mill comprising, in combination, a rotating grinding ring having a hub portion, an intermediate portion, and a rim portion, the intermediate portion being provded on its under side with a plurality of spring seats, and the rim portion being provided on its upper side with a grinding surface, an annular series of grinding element's supported on the surface, a non-rotary grinding ring arranged above the rim portion and provided on its under side with a grinding surface, a drive shaft supported from above the grinding rings and extending downwardly through and below the hub portion .of the rotating ring and having a driving connection therewith, a spring-carrying collar secured adjacent' the end of the drive shaft and being disposed beneath the spring seats, compression springs operative between the spring seats and the spring-carrying element for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for applying grinding pressure on the grinding elements, and spring adjusting means carried by the sprin carrying element.

5. A pulverizer mill comprising, in combination, a casing, a fixed grinding ring carried by the casing and having a grinding surface on its lower side, a rotating grinding ring having a substantially horizontal rim portion disposed below the fixed ring, the rim portion having a grinding surface on its upper side disposed adjacent the peripheral edge of the ring, an annular series of grinding elements supported on the last-named grinding surface and being operative between said grinding surfaces, means rotating with the rotating grinding ring for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for exerting yielding upward pressure of the rotating grinding ring and grinding elements supported thereby, means for feeding material to be pulverized to the inner side of the grinding elements for movement outwardly across the grinding surfaces, a cylindrical element removably secured to the outer peripheral face of the rotating grinding ring and extending above the level of said peripheral edge and including an upper screen portion, said element functioning as a dam for retarding discharge of the pulverized material until it has been reduced sufficiently as to pass through the screen portion and being vertically adjustable with reference to the rotating grinding ring.

6. A pulverizer mill comprising, in combination, a casing, a fixed grinding ring carried by the casing and having a grinding surface on its lower side, a rotating grinding ring having a substantially horizontal rim portion disposed below the fixed ring, the rim portion having a grinding surface on its upper side disposed adjacent the peripheral edge of the ring, an annular series of grinding elements supported on the lastnamed grinding surface and being operative between said grinding surfaces, means rotating with the rotating grinding ring for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for exerting yielding upward pressure on the rotating grinding ring and grinding elements supported thereby, means for feeding material to be pulverized to the inner side of the grinding elements for movement outwardly across the grinding surfaces, a cylindrical element removably secured to the outer peripheral face of the rotating grinding ring and extending above the level of said peripheral edge, a cylindrical screen secured to the cylindrical element along the upper edge of the latter, said element and screen functioning as a dam to retard discharge of the pulverized material until it has been reduced suificiently as to pass through the screen, and said element and screen being vertically adjustable with reference to the rotating grinding ring.

'7. A pulverizer mill comprising, in combination, a vertically arranged casing part provided intermediate its ends with an inwardly directed ledge, a non-rotary grinding ring removably supported on said ledge, releasable means for fixedly securing the ring on the ledge, the ring having a grinding surface on its under side, a rotating grinding ring having a rim portion disposed below the non-rotary ring, the rim portion having a grinding surface on its upper side, an annular series of grinding elements operative between said grinding surfaces, driving means for the rotating ring, means rotating with the rotating ring for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for exerting yielding upward pressure on the rotating grinding ring and the grinding elements supported thereby, and means for feeding material to be pulverized to the inner side of the grinding elements for movement outwardly across the grinding surfaces.

8. A pulverizer mill comprising, in combination, a vertically arranged casing part provided intermediate its ends with an inwardly directed ledge, a non-rotary grinding ring removably supported on said ledge, releasable means for fixedly securing the ring on the ledge, means operative upon release of said first means for raising the ring from said ledge, the ring having a grinding surface on its under side, a rotating grinding ring having a rim portion disposed below the non-rotary ring, the rim portion having a grinding surface on its upper side, an annular series of grinding elements operative between said grinding surfaces, driving means for the rotating ring, means rotating with the rotating ring for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for exerting yielding upward pressure on the rotating grinding ring and the grinding elements supportedthereby, and means for feeding material to be pulverized to the inner side of the grinding elements for movement outwardly across the grinding surfaces.

9. A pulverizer mill comprising, in combination, a vertically arranged casing part provided intermediate its ends with an inwardly directed ledge, a non-rotary grinding ring removably supported on said ledge, releasable means for fixedly securing the ring on the ledge, the ring having a grinding surface on its under side, a rotating grinding ring having a rim portion disposed below the non-rotary ring, the rim portion having a grinding surface on its upper side, an annular series of grin-ding elements operative between said grinding surfaces, driving means for 'the rotating ring, means rotating with the rotating ring for carrying the entire weight of the rotating ring and the grinding elements supported thereon and for exerting yielding upward pressure on the rotating grinding ring and the grinding elements supported thereby, the casing being provided with a material inlet disposed above the grinding rings, and said grinding rings being constructed and arranged to direct material entering the casing to the inner side of the grinding elements for movement outwardly across the grinding surfaces.

HARRY R. COLLINS.

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