US2149581A - Pulverizer mill - Google Patents

Description

March 7, 1939. H co s I 2,149,581

PULVERIZER MILL Filed Aug. 12, 1956 gwuc-MM I-l P. CO LL) N5 Patented Mar. 7, 1939 PATENT OFFICE PULVERIZER MILL Harry R. Collins, Allentown, Pa.; May H. Collins administratrix of said Harry R. Collins, de-

ceased Application Aug ust 12, 1936, Serial No. 95,659

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 5 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 horizontal plane to actuate the balls.

Among the objects of the present invention may be noted the provision of a mill of simple and practical construction in which reduction of the material under treatment is: accomplished in a single stage, the mechanism contemplating an arrangement in which a grinding assembly of the stated character and the driving mecha nism 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, instal- 25 lation, 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'charactenin which the weight of the rotating element or surface of the grinding assembly is carried by the grinding elements, thus to apply grinding pressure thereto, and in which grinding pressure may further be adjusted to the material under treatment insimple manner and by readily accessible means, with provision being made for regulation of the degree 4 of fineness of the product to. satisfy varying requirements. 1 Other objects will be in part obvious and in part hereinafter pointed out in connection with the accompanying drawing illustrating one embodi- 45 ment in elevation, and partly in section, of a pulverizer mill in accordancewith my invention.

Referring to the drawing, reference character Iii designates a generally cylindrical casing constituted by a lower casing section II, provided 50 with an annular flange l2 which may serve as a bed plate for the apparatus, and an upper section [3. Between the casing sections H and I3 is arranged a main bearing support I4, with bolts .or equivalent securing means I5 removably securing the bearing support [4 to facing flanges of the aforesaid casing sections. The upper casing section I3 is provided with a horizontal top plate l8 which serves to close the top of the casing ll] as formed by the casing sections as aforesaid.

Arranged on the top plate 18 of casing section '5 l3 and suitably secured thereto is a vertically disposed motor 20 for the drive assembly, the motor shaft 2| of which extends through the top plate l8 and into the chamber or compartment formed by the casing section I3, its top plate l8, and the main bearing plate I4.

Motor shaft 2! carries a hardened steel pinion 22 which drives oppositely arranged idler gears 23, 24 carried bybearings on suitable shafts 25, 26, respectively, secured in the cover plate l8 of the top casing section. Idler gears 23, 24 mesh with a ring gear 28 carried by a circular supporting plate 3tl,'the latter being secured as by bolts 3! to a flange formedon the upper end of the main driving shaft 32, the upper portion of which is circularin cross-section.

The main bearing plate I4 is provided with a 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 tapered roller bearings 34, 35, the inner raceways being carried by the main driving shaft 32. Said bearings are suitably lubricated as by grease injected through a bore (not shown) in the main bearing plate M. A packing ring 36 operative between the lower end of the plate hub- 33 and the driving shaft 32 serves to exclude entry of dust along the'shaft and into the driving mechanism. Main bearing plate hub 33 extends upwardly above the top horizontal surface of the main bearing plate l4, and hence there is formed within the compartment which houses the driving assembly as aforesaid an annular well or reservoir adapted to contain a quantity of lubricating oil for the elements of the driving assembly, such being supplied to the reservoir through a port 4|] extending through the main bearing plate and communicating with an oil supply line indicated The bottom plate of the ring gear 28 is pro vided with one or more apertures as at 42, and threaded into each of said apertures is a scoop pipe 43 which extends downwardly into theoil 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 forming 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 plate 18 of casing section 13, and into a two-part housing 45 suitably secured to the casing top plate I8, the housing 45 containing drive elements for a rotating feed table 46.

The feed table drive as aforesaid preferably consists of a worm pinion 41 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 surface (not shown) in driving relation to a pinion 58 carried by vertical feed table shaft 5|. 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 including pinion Z2, idler gear 23, pinions 47 and 50, and the gear surfaces of shaft 48.

To lubricate drive parts contained in housing 45, top platel8 of the casing section I3 and the bottom wall of housing 45 are provided with a set of aligned apertures, and threaded into said apertures is a scoop pipe 52, the lower open endof which extends into the cavity or secondary oil reservoir formed by ring gear'28 and its bottom plate 30, 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 drive elements therein contained.

The lower half or end of the main shaft 32 is of square or other angular section and extends through central openings in a spring-abutment disc 54 and the hub 55 of a movable grinding ring 56, such openings being slightly larger than the shaft whereby movable grinding ring 56 is permitted limited movement to maintain alignment regardless of any inaccuracies in manufacture or normal wear of the grinding elements. The spring abutment disc 54 engages, due to the pressure of compression spring 58, against a shoulder provided on the driving shaft between the upper circular and the lower square portion thereof adjacent the ring 36 and is provided with spaced pockets 5'! in each of which seats an end of a series of the compression springs 58 (only one being shown), the other ends of which engage against spring heads 59 disposed in spaced pockets formed in the movable grinding ring immediately adjacent and outwardly of the ring hub 55. Compression bolts 60 passing through threaded apertures in the movable ring 56"operate through heads 59 to compress springs 58 against the vertically fixed seating disc 54, the boltsbeing held in adjusted position as by the lock nuts 6|.

The movable grinding ring 56 extends upwardly in cylindrical wall formation about the compression' springs 58 and thence outwardly to provide a horizontal rim portion. 62, the under surface of which is suitably recessed to receive a welded or otherwise secured raceway 65 provided on its under surface with a circumferential groove or channel. The curvature of the channel corresponds to that of the grinding balls 66 arranged in annular series and supported in a circumferential channel or groove'formed in a raceway 61 secured as by welding to a fixed ring 68, with the parts 61, 68 constituting the fixed ring of the mechanisms are separate assemblies.

grinding assembly. The curvature of the lower channel also corresponds to that of the grinding balls, and the lower channel is disposed directly beneath the channel of the rotating ring 65.

The fixed ring 68 is generally horizontally disposed and its rim portion seats on" an annular ledge or shelf 18 which extends radially inwardly from the inner wall of casing section I I, the ring having a centering flange extending from its under face to engage against the inner peripheral face of the ledge. Ring 68 is removably secured in seated relation against said ledge as by two or more holding bolts H which may project through a thickened portion 12 formed on the outer wall of the casing section II. Bolts H are arranged to bear against an inclined upper surface of the fixed rings 68 and are maintained in position by suitable lock nuts; Fixed ring lifting bolts 15 are also provided and operate, upon unthreading of bolt H from its holding position with respect to the fixed ring, to engage against an under surface of the fixed ring to force the same upwardly and out of seating relation with respect to the ledge 18 when disassembling.

Secured as by welding to the rim 62 of the movable grinding ring and extending upwardly therefrom is a cylindrical guard ring which terminates at about the upper level of the inlet opening 8| through which material delivered to the hopper 82 by the feed table 46 enters the casing. Thus, guard ring 80 prevents flow of material inwardly and, instead, causes material to be directed downwardly to the outer side of the grinding balls and onto the fixed plate 68 where it builds up and then passes under the grinding balls 66. The flow of material is thus downwardly and inwardly.

The inner edge of the fixed ring 68 carries a dam 83, adjustable in height, which extends upwardly into the space between the cylindrical portion of the rotating ring 56 and the inner or discharge side of the grinding balls, and functions to control the degree of fineness of the material being ground, The dam carries a cylindrical screen 84 which controls discharge of material of desired fineness following its treatment by the grinding balls, the pulverized material thereupon dropping through grating 85 into the air stream induced by exhaust fan. 86 arranged below the casing l8. One or more air inlet openings 81 to the fan are formed in the casing adjacent the bottom of section ll thereof as desired.

The fan 86 is driven by a shaft 88 which passes upwardly through a bore 90 in the main driving shaft 32 and is secured to the hub of the driving pinion 22. The lower end of the shaft 88 is supported'for rotation in a bearing formed in the lower fan section (not shown).

It will thus be seen that the motor 20 drives the fan 86 at full load speed, whereas the grinding balls are driven circumferentially of the mill at a reduced speed which preferably corresponds to gravity fall of the material, through the speed reducing effect of the driving mechanism as aforesaid.

It will be understood that a slurry pump can be substituted for the fan 86 when wet grinding is contemplated.

In a p'ulverizer mill according to the foregoing, the symmetrically disposed driving and grinding Thus, by removal of the holding bolts l5, top casing section [3 may be removed, thus to permit access to the driving mechanism supported by the main bearing plate I4, and further, by raising the main tially uniform.

maybe removed from the easi'rig'thustopenmt access to the grinding assembly or to permit re moval of the latter for the purpose of replacing worn parts. a 7 7 Further, with the grinding assembly of the presen invention, grinding pressures can be adjusted to the material under treatment, with the dam 83 on the'outlet or discharge side of the annular series of grinding balls functioning to control the degree of fineness of the material passing through screen 84. Thus, particle size can be closely controlled and the resulting product will be substan- Ihe lubricating'and feed table driving means shown herein are claimed in my copending application, Serial Number 95,657, filed of even date herewith.

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 pulverizing mill comprising, in combination, a casing, a fixed grinding ring carried thereby, a rotating grinding ring, an annular series of grinding elements operatively arranged between the rings, the rotating ring having a central shaft opening of angular section, a drive shaft supported from above the grinding rings, the shaft extending downwardly through the opening and having a lower portion of angular section corresponding to the angular section of the ring opening, whereby to provide a driving connection with the rotating ring, driving means for the shaft, and means rotating with the shaft and the rotating ring for exerting yielding grinding pressure on the grinding elements, said means including a spring abutment member disposed above the rotating ring and compression springs operative between the member and the rotating ring, the abutment member having a central shaft opening of angular section corresponding to that of said lower shaft portion, whereby the shaft has a driving connection with the member, both said shaft openings being larger than said lower shaft portion whereby the shaft may be raised freely out of driving connection with the rotating ring and said member.

2. A pulverizing mill comprising, in combination, a casing, a fixed grinding ring carried thereby, a rotating grinding ring, an annular series of grinding elements operatively arranged between the rings, the rotating ring having a central shaft opening of angular section, a drive shaft sup: ported from above the grinding rings, the shaft extending downwardly through said opening and having an upper portion of cylindrical section and lower portion of angular section corresponding to the angular section of the ring opening, whereby to provide a driving connection for the rotating ring, a shoulder on the shaft disposed between the circular and angular portions thereof, driving means for the shaft, and means rotating with the shaft and the rotating ring for exerting yielding grinding pressure on the grinding elements, said means including a spring abutment member disposed above the rotating ring and compression springs operative between the member and the rotating ring, the abutment member having a central shaft opening of angular section corresponding to that of said lower shaft portion, whereby the'shaft has a driving connection with the member, said springs being operative to bosition the member against the shoulder whereby to provide a surface against which the springs react,both said shaft openings being larger than said lower shaft portion, whereby the shaft may be raised freely out of driving connection with the rotating ring and said member.

3. A pulverizer mill comprising, in combination,

a casing, a fixed grinding ring carried by the casing, the fixed ring being substantially horizontal and having a grinding surface on its upper side disposed adjacent the inner peripheral edge of the ring, an annular series of grinding elements supported on the grinding surface, a rotating grinding ring supported by the grinding elements, the rotating ring having a substantially horizontal rim portion with a grinding surface on the under side thereof, means for driving the rotating ring, said means being supported from above the grinding rings and including a drive shaft extending downwardly through the rotating ring and having a drive connection therewith, means rotating with the rotating ring for exerting yielding downward pressure on said ring and the grinding elements, the casing having a material inlet opening disposed above the grinding rings, means for excluding material to be pulverized from the driving means and for directing the material to the outer side of said grinding elements for movement inwardly across the grinding surfaces, and a cylindrical element removably secured to the inner peripheral face of the fixed 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 sufiiciently as to pass through the screenportion and being vertically adjustable with reference to the fixed ring.

4. A pulverizer mill comprising, in combination, a casing, a fixed grinding ring carried by the casing, the fixed ring being substantially horizontal and having a grinding surface on its upper side disposed adjacent the inner peripheral edge of the ring, an annular series of grinding elements supported on the grinding surface, a rotating grinding ring supported by the grinding elements, the rotating ring having a hub portion, an upwardly extending intermediate portion disposed inwardly of the grinding elements and of the fixed ring, and a substantially horizontal rim portion provided with a grinding surface on its under side, means for driving the rotating ring, said means being supported from above the grinding rings and including a drive shaft extending downwardly through the rotating ring and having a driving connection therewith, means rotating with the rotating ring for exerting yielding downward pressure on the rotating ring and said grinding elements, the casing being provided with a material inlet disposed above the grinding rings, means carried by the rotating ring and extending upwardly thereof to exclude material entering the casing from the driving means and to provide with the inner wall of said casing a path of material fiow to the outer side of the grinding elements, and a cylindrical element including an upper screen portion removably secured to the inner peripheral face of the fixed grinding ring and extending upwardly thereof into the space between the grinding elements and the intermediate portion of the rotating ring, said element functioning as a dam for retarding discharge of the pulverized material until it has been reduced sufiiciently to pass through the screen portion thereof and being vertically adjustable with reference tothe fixed ring.

5. A pulverizer mill comprising, in combination, a vertically arranged casing part provided intermediate its ends with an inwardly directed V ledge, a fixed grinding ring removably supported along its outer peripheral portion on said ledge,

ring for lifting said ring from the ledge upon release of said securing means, the ring having a grinding surface on its upper side disposed adjacent the inner peripheral edge of the ring, a rotating grinding ring having a rim portion disposed above the fixed ring, the rim portion having a grinding surface on its under 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 exerting yielding downward pressure on the rotating ring and the grinding elements, and means for feeding material to be pulverized to the outer side of the grinding elements for movement inwardly across the grinding surfaces.

HARRY R. COLLINS.

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