US2071381A - Pulverizing unit - Google Patents

Description

Feb. 23, 1937. R. M. HARDGROVE 2,071,381

PULVERIZING UNIT Filed Nov. 16, 1931 4 Sheets+Sheet 1 A OFQNEY Feb. 23, 1937. R. M. HARDGROVE PULVERIZING UNIT Filed Nov. 16, 1951 4 Stieets-Sheet 2 INVENTOR Feb. 23, 1937.

R. M. HARDGROVE PULVERIZING UNIT Filed Nov. 16, l93l Ill 5C5 4 Sheets-Sheet 3 INVENTOR Ralph M fblafyloz/e iiTORNEY Feb. 23, 1937. R. M. HARDGROVE mmvnnxzme UNIT Filed Nov. 16, 1951 4 Sheets-Sheet 4 a Y RH M m R N m w ml Patented Feb. 23, 1 937 PULVERIZING UNIT Ralph M. Hardgrove, Westfield, N. J., assignor, by mesne assignments, to The Babc'ock & Wilcox Company, Newark, N. J., a corporation of New Jersey Application November'16, 1931, Serial No. 575,317

' 12 Claims.- (01. 83-45) This invention is a pulverizing unit. which includes a pulverizer, and a blower and material feeder therefor, together with a unitary driving means thereby maintaining a ratio of air 5 and material never in excess of the capacity of the pulverizer.

In pulverizers of the type including a stationary and movable ring, with rolling elements therebetween, it has been customary to mount the driving mechanism below the pulverizing mechanism with the consequent disadvantage of considerably elevating the stationary pulverizing ring above what could otherwise be the natural foundation level of the total assembly. Thus the construction is expensivein that the component parts have to be heavier than would be necessary were the stationary pulverizing ring not elevated above the driving mechanism. Furthermore such a construction brings the material entrance and pulverulent particle exit higher than is con venient for the usual location with respect to auxiliary equipment. The present invention considerably lessens the weight and expenseln- 'cident to this type of equipment by bringing the W stationary ring down to the levelof the natural foundation. According to the present invention the driving mechanism is placed at the top, and incidental thereto, but of equal importancejthe present invention also makes possible a reduction in the height at which the materi-al is fed and the pulverulent particles taken off, thereby rendering the pulverizer more compact and easier to install in connection with auxiliary equipment. from the economic standpoint.

Previously it has been the practice, incident to driving from the bottom to carry the total pressure due to grinding pressure adjustment and the weight of the parts upon a vertical shaft havingits total thrust absorbed upon an end thrust bearing. When using the inverted or top drive forming a part of the present invention the driving mechanism is free of the weight of the movable grinding ring, together with its adjustment parts and intermediate driving element, and the thrust bearing absorbs only the thrust of the grinding adjustment as reduced by the weight of the parts mentioned. This construction is thus another feature of the invention.

Current practice, up to the time of this invention has been to introduce the materialto be pulveri aed downwardly and inwardly between and among; rollers separating two ring members, and to distribute the air sweeping blast upwardly and 5 centrally of the pulverizing rings. This has a This isoi great advantage tendency to prevent easy entrance of some oi. the coarse particles to the grinding zone. A construction in accordance with the present invention not only introduces the material to be reason of an arrangement which introduces the air sweeping blast in the same direction as the material, to wit: inwardly from the external peripheries of the grinding rings between the same and among the roller elements and sweeping therewith the finely divided or pulverulent particles and thence carrying the same upward-, ly beyond the grinding elements and out at the top of the enclosing casing. Thus the air travel is over the same path as the material travel, and the air assists the movement of material as it is being fed to the grinding elements.

The present invention also contemplates a vertical pulverizer with an arrangement of a stationary grinding ring in combination with a floating movable grinding ring and a driving mechanism therefor. This includes a floating driving connection which permits the floating grinding ring and the floating driving connection to have free relative displacement with respect to each other, and to. the main driving mechanism, thereby relieving the latter of an .appreciable amount of strain and consequent wear. This contributes to longer lifeof the unit and reduced power consumption, and. thereby materially decreases the cost per ton of mate- 5 rial operated upon. I] I Sealing means to protect the driving shaft and bearing parts against the abrasive action of the pulverulent particles is another feature of pulverizing' units that has presented considerable 40 difiiculty, and this present invention again contributes to lessened depreciation and overall upkeep cost by utilizing the air from the blower thatmfurnishes the air sweeping blast to accomplish this function. This is accomplished in a particularly novel way in that the shaft is surrounded by a sealing pocket into which air is introduced by the same blower furnishing air to the enclosing casing of the pulverizer, as above stated. However the parts are-so arranged so with respect to each other that the velocity component .of the air blast is translated intoan always greater pressure component. than the total pressure, existing in the pulverizer casing, and thus air may always escape around the shaft and into the pulverizer casing thereby effectively excluding dust particles and reducing wear to as absolute minimum in so far as the bearing parts of the driving mechanism are concerned.

A further feature of the invention is the provision of an adjustable skirt dividing the material feeding area from the air blast entrance area and thus providing means for regulating the air velocity in the zone adjacent the grinding elements.

Additionally, the invention contemplates a table feeder including a rotary disc receiving and moving the material into the pulverizing casing. The amount of material entering the apparatus is controlled by a valve actuable along the active surface of the table feeder disc, and the disc is driven from the same motive element which drives the blower and pulverizer. Thus as previously stated, the material and air are regulated in accordance with the capacity of the pulverizer.

In the foregoing the novelty and utility of the invention has been pointed out and, in connection with the accompanying drawings forming a part of this specification,. I shall now describe a particular embodiment of the invention for the purpose only of making such a disclosure as is required by the patent statutes.

In the drawings:

Figure 1 is a side elevation of a pulverizer unit, partly in section and showing the table feeder;

Fig. 2 is a top plan view thereof;

Fig. 3 is a vertical central section on the line 3-3 of Fig. 2;

Fig. 4 is a sectional view on the line 4-4 of Fig. 3;

Fig. 5 is a sectional view on the line 5-5 of Fig. 3.

In the drawings a foundation plate I has secured thereto a stationary grinding ring 2 by any suitable means, such, for instance, as welding, and the upper face 3 thereof is provided with a race 4 in which rolling elements 5, such as balls, may travel. The outer periphery 6 of the race 4 is annularly beveled outwardly, as shown, to assist material to be pulverized in gravitating beneath and between the balls 5.

A central member I secured to the foundation plate I by a cap screw 8 may substantially close the opening in the lower stationary grinding ring 2,

Above the stationary grinding ring 2, and in opposed relation to the race 4 thereof, and on top of the balls 5 which seat in its race 9 is a floating ring I, the outer periphery of which overhangs the balls 5 and carries scraper lugs or plows I I, while the inner opening is provided with lugs l2 which engage in loose driving relation with similarly arranged lugs H! on a floating driving member l4; wearing plates l5 are bolted or otherwise secured to either lugs l2 or I 3.

The central portion of the driving connection I 4 extends outwardly and carries four radial arms l6, at the outer end of each of which is an adjusting screw I! with a lock nut l8, and the lower end of each adjusting screw contacts with a sooketed cap l9 bearing on the upper end of a spring 20 seated over a spring retaining member 2| on the upper side of the floating grinding ring Ill. By adjusting" the screw H the compression of the spring 20 may be increased or decreased to exert a greater or lesser pressure upon the ring .10 and thereby regulate the grinding adjustment existing between the rings 2 and I 0 and the balls 5.

The arms l6, at their center, engage with a clutch member 22 having jaws 23 which enter cooperating spaces provided by the shape of the arms I6 and thereby engage the clutch member 22 and the member l4 in loose driving relation.

It is to be noted that by this arrangement the ring ID has a floating action with respect to the member l4, and the member l4 has a floating action with respect to the clutch member 22 so that rocking of the elements with respect to each other during grinding operation is freely permitted without imposing any appreciable strain on the main driving mechanism to be hereinafter described.

Surrounding the grinding rings 2 and I0 is an annular member 24, the upper portion of which is beveled outwardly as indicated at 25 to an angle corresponding with the face 6 of the race 4 of the lower grinding ring 2, and such beveled portion 25 therefore is adapted to receive and direct air and material between and among the balls 5.

This annular member 24 is surrounded in spaced relation by an outer casing 26 except that it contacts therewith along the upper edge. Inwardly of the casing 26 and in concentric relation therewith, is a skirt member 21 thus forming an air passage 28 between the casing 26 and said member 21 which delivers air downwardly onto the inclined surface 25 of the annular member 24, in a direction to sweep between the grinding rings 2 and I0 and among the balls 5. The lower end of this skirt 2'! has slots 29. which are engaged by bolts 30 holding a drop ring 3| in position to be raised or lowered with respect to the inclined surface 25 either to increase or reduce the velocity of air entering the pulverizing zone.

An entrance opening is provided in the casing 26 and through the skirt 21, and is closed by a door 32 provided with handles 33, as shown, and suitably secured in place by the members 34 which are simply swing bolts 35' engaging in lugs 36 carried by the door.

Referring again to the driving mechanism, the clutch member 22 is carried upon the tapered end 31 of a shaft 38, and is additionally secured against rotation with respect to said shaft by the key 39, and is held on the end of the shaft by the disc 40 secured by the bolt or cap screw 4|, the upper end of the member [4 being recessed as shown at 42 to accommodate said disc 40 and the head of the cap screw 4|, the partition 43 being provided to prevent the cap screw 4| or disc 40 from dropping down into the lower part of the mechanism should it become loosened.

The casing 26, at the top, is closed by a cover plate 44 having outlets 45 therein to provide for the exit of the pulverized material. The cover plate 44 mounts a bevel gear housing 46 through the medium of supporting legs 41 secured to the cover plate 44 by cap screws 48. Said bevel gear housing 46 has a chamber 49 axially alined with and receiving the shaft 38. A radial bearing 50 is in the lower end of the chamber 49 and acts to support the shaft 38, while the upper end of said shaft carries a bevel gear 5| keyed thereto as at 52, and the shaft 38 extends beyond the bevel gear and through a radial bearing 53 mounted in a' cover plate 54 closing the gear housing 46 and an oil chamber 55 formed there- The upper end of the shaft 38, in connection with the cap member 54, carries a thrust bearing 56 which absorbs the grinding pressure, but it is by the fact that the driving parts and adjusting pulley I4 for driving the pulverizer.

in a downward direction.

The shaft 38 has an extension 51 through the top of the cap 54 which carries a small bevel gear 58 for purposes to be hereinafter described.

The oil chamber 55 is eouipped with an oil level gauge 58, as shown,- and with a filler plug 88. At the side of thefbevel gear housing 48 is an extension 8| flanged as at 82 and bored out to receive a cooperating bearing carrying member 83 provided with radial thrust bearings 84 and 55, the fiange 82 being bolted to a flange 68 of the bea, ng carrying member 83 in any suitable manner, and the two bearings supporting a pinion shaft 6'! at the inner end of which is keyed, as at 68, a pinion 68 held on the shaft by a nut I8 and meshing with the bevel gear to drive the shaft 38 when power is applied to the pinion shaft 61.

An oil sealing gland 'II surrounds the outer end of the shaft which is extended as at I2 and provided with a keyway I3 for the mounting of a pulley or sprocket I4 constituting a part of the drive, as will be hereinafter described.

Within the pressure chamber formed by the casing 28 and surrounding the shaft 38 below the radial bearing 58 is an annular drop well I5 hav-- ing a transverse partition I8 provided with packing I1 and closing pate I8 bolted in place as shown to seal the shaft 38. Immediately below the closing plate I8 is a partition I8 having bolted thereto a closing plate 88 extending inwardly to the shaft 38, but with no packing. The chamber thus formed will be hereinafter referred to as the sealing pocket 8|.

Adjacent the casing 28 is a positive pressure blower 82 having an air entrance 83 and an impeller 84 carried on the shaft extension 85 of a motor 88. The other end of the shaft carries a driving pulley 81 which is belted or connected in. driving relation by the element 88 to the The air outlet 88 of the blower is connected to the air inlet 88 of the casing 28 in such manner that the air enters the annular space 28 tangentially and circulates around the annular space 28 with a swirling motion and is exhausted through the opening between the casing 26 and the adjustable member 3| of the skirt 21 inwardly in the general direction of the inclined face of the annulus 24 adjacent the grinding elements, thus sweeping the fines into the air passing through the elements and up at the center and also around the outside thereof where they finally leave the casing through the openings 45.

A connection 8| opening into the chamber 8| is brought into a position to receive the full velocity of the air leaving the blower and carries air to the chamber 8| where it has its velocity component translated into a pressure component always greater than the pressure component in the chamber formed by the casing 26, and thus air continuously escapes between the shaft 88 and plate 88 thereby preventing any dust particles from reaching the interior of the casing 8| and consequently from reaching the sealing means 11 or the bearings of the shaft 38.

.At the side of the casing 26 is a table feeding mechanism which comprises a casing 82 having apartition 83 secured thereto and mounting a rotatable disc 84. The disc 84 has a shaft 85 which is provided with a gear 85 meshing with a pinion 81- for driving the disc or table 84. The shaft 85 is connected by a shaft 88 supported in a bearing 88 with a shaft I88 by means of a universal joint I8I. A second universal joint I82 connects the shaft I88 with a stub' shaft I83 supported in the bearing I84. The shaft I83 carries a bevel gear I85 meshing with the bevel pinion 58 on the end of the shaft 38. Thus the motor 88 drives the pulverizer. the blower and the table feeder, the whole assembly forming a unitary apparatus.

An annulus I88 within the casing 82 and se- I cured to the bracket 83 prevents material from spilling beneath the table to any great extent.

The annulus I86 carries guiding means I81 which guides the material discharged from the table through the opening I88 into the casing 28. From that location the material falls onto the beveled surface 25 of the annular member 24 surrounding the grinding elements,;thus entering between the grinding rings 2 and I8 and among the balls 5.

A journal I 88 in the top of the casing 82 carries a shaft II8 which carries an arcuate vane or gate I I2 within the casing and extending partly across the table 84. The gate 1 I2 cooperates with a fixed curvilinear wall extending inwardly from the opposite side of the casing 82 at one side of the entrance |88to define a segmental material inlet section to which a supply connection II3 opens. The convex side of the fixed curvilinear wall is arranged in opposition to the direction of rotation of the table. The gate II2 when closed is arranged as shown in dotted lines in Fig. 1 and swings toward the casing wall to allow material on the table to pass through the opening formed between the gate and fixed curvilinear wall out of the material inlet section. The fixed wall acts as a scraper to deflect material into the entrance I88. The upper end of the shaft 8 which carries the arcuate gate II2 extends outside of the casing 82 and carries a lever arm II4 connected with a second lever arm II5 which may be secured in any adjustable position by a rocking means I I8, and through the medium of a lever 5 the gate or vane 2 may be positioned to any adjusted opening to regulate the feeding of the material.

On the top of the casing 82 are lugs III which secure an inspection plate 8 in place.

It will be seen from the foregoing that I have I provided a top drive mill with a floating upper grinding ring, a floating connection between the grinding ring and the driving mechanism, and a solid bottom ring, and that the parts are interconnected for driving purposes so that a single drive accomplishes the operation of all three elements, namely, the puiverizer, the blower and the table feeder.

While in the foregoing I have set forth a spe cific form of the invention, it is nevertheless to be understood that in carrying the same into practice I' may resort to any and all modifications falling within the scope of the appended claims defining my invention. In the claims, the term "air is used generically to cover any gaseous carrier medium suitable for removing pulverized material in the manner described.

I claim: 7

1. A pulverizer including astationary and a movable grinding ring in opposing relation, rolling grinding elements therebetween, driving mechanism for said movable grinding ring, a casing for the pulverizer and a concentric shell within said casing forming an annular peripheral entrancebetween said rings for introducing air and material to be pulverized, means for-feeding air and material thereto, and means annularly dividing the entrance between said rings and adjustable to regulate the air velocity in the zone adjacent the grinding elements.

2. An air-swept pulverizer comprising a casing having an outlet for material-laden air in its upper portion, a non-rotary bottom grinding ring, a circular row of rotary grinding elements supported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a floating drive connection with said top ring and a plurality of radial arms, a compression spring positioned between each of said radial arms and said top ring, an adjusting screw on each of said radial arms for adjusting the compression of the corresponding spring, a main drive shaft above and coaxial with said spider and extending through the top wall of said casing, means forming a clutch connection between said shaft and spider, means externally of said casing for driving said shaft, means for delivering material to be pulverized to the outer side of said row of grinding elements, and means causing a current of air to sweep up pulverized material and carry the same upwardly to said casing outlet.

3. An air-swept pulverizer comprising a casing having an outlet for material-laden air in its upper portion, a non-rotary bottom grinding ring, a circular row of rotary grinding elements supported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a floating drive connection with said top ring and a plurality of radial arms, a compression spring positioned between each of said radial arms and said top ring, an adjusting screw on each of said radial arms for adjusting the compression of the corresponding spring, a main drive shaft above and coaxial with said spider and extending through the top wall of said casing, means forming a clutch connection between said shaft and spider, means externally of said casing for driving said shaft, means for delivering material to be pulverized to the outer side of said row of grinding elements, openings in said top ring for the passage of material-laden air. and means causing a current of air to sweep up pulverized material and carry the same upwardly through the openings in said top ring to said casing outlet.

4. An air-swept pulverizer comprising a casing having an outlet for material-laden air in its upper portion, a non-rotary bottom grinding ring, a circular row of rotary grinding elements supported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a floating drive connection with said top ring and a plurality of radial arms, a compression spring positioned between each of said radial arms and said top ring, an adjusting screw on each of said radial arms for adjusting the compression of the corresponding spring, a main drive shaft above and coaxial with said spider and extending through the top wall of said casing, means forming a clutch connection between said shaft and spider, means externally of said casing for driving said shaft, means for delivering material to be pulverized to the outer'side of said row of grind- 7 ing elements, a plow mounted on said top ring at the outer side of said row of grinding elements, and means causing a current of to sweep up pulverized material and carry the same upwardly to said casing outlet.

5. An air-swept pulverizer comprising a casing having an outlet for material-laden air in its top wall, a non-rotary bottom grinding ring, a circular row of rotary grinding elements supported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a floating drive connection with said top ring and a plurality of radial arms, a compression spring positioned between each of said radial arms and said top ring, an adjusting screw on each-of said radial arms for adjusting the compression of the corresponding spring, a main drive shaft above and coaxial with said spider and extending through the top wall of said casing, means forming a clutch connection between said shaft and spider, means externally of said casing for driving said shaft, means including an inclined baffie for delivering material to be pulverized to the outer side of said row of grinding elements, a plow mounted on said top ring at the outer side of said row of grinding elements, openings in said top ring for the passage of material-laden air, and means causing a current of air to sweep up pulverized material and carry the same upwardly through the openings in said top ring to said casing outlet.

6. A pulverizer comprising a bottom grinding ring, a circular row of rotary grinding elements supported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a plurality of arms, a compression spring positioned between each of said arms and said top ring, a drive shaft for said spider and top ring, means for delivering material to be pulverized to the outer side of said row of grinding elements, and means causing a current of air to sweep up pulverized material and carry the same upwardly within said row of grinding elements.

7. A pulverizer comprising a non-rotary bottom grinding ring, a circular row of rotary grinding elements supported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a plurality of arms, a compression spring positioned between each of said arms and said top ring, an adjusting screw on each of said arms for adjusting the compression of the corresponding spring, a main drive shaft above and coaxial with said spider, said drive shaft extending downwardly through the top wall of said casing with its lower end terminating above said row of grinding elements, and means for delivering material to be pulverized to one side of said row of grinding elements.

8. A pulverizer comprising a non-rotary bottom grinding ring, a circular row of rotary grinding elements ssupported on said bottom ring, a rotary top grinding ring supported on said grinding elements, a rotary spider having a drive connection with said top ring and a plurality of arms, a compression spring positioned between each of said arms and said top ring, an adjusting screw on each of said arms for adjusting the compression of the corresponding spring, a main drive shaft above and coaxial with said spider with its lower end terminating above said row of grinding elements, means forming a clutch connection between said shaft and spider, means for driving said shaft, and means for delivering material to be pulverized to one side of said row of grinding elements.

9. An air-swept pulverizer comprising a casing having an outlet for material-laden air in its upper portion, a bottom grinding ring, a circular row of rotary grinding elements supported on said bottom rin a rotary top grinding ring supported on said grinding elements, a rotary having aplurality of arms, a compression spring positioned between each of said arms and said top"r ing, 'a drive 'shatt'for. said spider and top ring, means for delivering material to be pulverized to the outr side of said row of grinding ele-.

its upper section, a bottom grinding ring, acirr cular row'of rotary grindingelements supported onisaid'bottom ring, a rotaryjop grinding ring supported on said grinding elements, 'a-rotary spider having a plurality of arms, a compression springpositioned between each of said arms and.

said top ring,a'dnive shaft for saidspider and top ring, an opening formed in sai'dtop ring for the passage of material laden air, means tor. de-,

livering material'to be pulverized to the outer" side '01 said row of grinding elements, and means causing a current of air to sweep upfpulverized material and ca'rrythe "same upwardly-through" said top ring'op'ening-to said casing, outlet.

11.-A pulverizer comprising a bottom grinding ring, a circular row of rotarygrinding elements supported on said bottom ring, a rotary, top

2,071,881 spider grindingrring to said grinding-ring supported-on said grinding ele- I ments, a rotary spider having a plurality of arms,

' a compression spring positioned between each of said arms and said top ring, a driver-shaft for said spider and top rin means for'delivering material to be pulverized to the outerside of said row oi grinding elements, and a plow' mounted o'h'saidv top ring at the outer side of said row of grindingelements. l g

12. An air -swept'pulverizercomprisin a casing having an outlet for material-laden air in its upper section, a bottom grinding ring,"a cir- 'cul'al; row of rotary grinding elements supported on' 'said bottom ring, a rotary top grinding ring supported on-said grinding elements, arotary spi der having a plurality of arms, a compression spring positioned between each of said arms and said top ring, a drive shaft for said spider and ,top ring, an opening formedin said *top ring '20 forthe passage of material-laden air, means for delivering material to be pulverized to the outer 'side'of said rowotgrinding elements, a plow mounted on saidtop ring at the outer side of said rowTof. grinding elements, and means causing a *current'oi air to sweep up pulverized material fand carry the same upwardly through said top 1 11218 opening "to said casing outlet,-

RALPH M. HARDGROVE.

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