US1431251A - Pulverizing apparatus - Google Patents

Description

R. El H. POMEROY.

PULVERIZING APPARATUS. APPLICATI'ON FILED Nov. 49. 1921.

1,431,251', Patented oct. 10,1921

2 SHEETS-SHEET I.

R. E. H. POMEROY. lPULVERIZING APPARATUS.

APPLICATION FILED NOV. I9. 192|.

Patented Oct. I, 1922.

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httllll narran stares, earner RALPE. E. POMERGY, 0F CANTON, 0R10.

PLVERIZING APPARATUS.

Application filed November 19, 1921. Serial No. 516,380.

To all whom t ma concern.'

Be it known that RALPH E. H. PoMERoY, residing at Canton, in the county of Stark and State of Ohio, a citizen of the United States, have invented or discovered certain new and useful Improvements in Pulveriz- Apparatus, of which improvements the 111 foiowing is a specification,

In applications Serial Nos. 393147 and 474079, filed respectivel June 30, 1920, and June 1, 1921, aredescri ed and claimed im` provements in pulverizing mills of the class .or type embodying a revoluble drum and balls or other hard bodies. The improvementsset forthin said applications provide' out of the drum, so that in many cases itis desirable to effect a grading of the material carried from the drum.

And further, it has been found. in the o eration of this type of mill the bulk 'of tige charge consisting of the material to be treated and the balls will be found in the uadrant between the planes coincident with t e horizontal and partial diameters of the drum, although portions will'extend beyond these planes, the vatest depth of the charge belng generally ound adjacent to the plane passlng through the vertical diameter and the charge will taper or decrease in depth to a point above the plane coincident-with the horizontal diameter, a distance dependentupon .the speed of'rota tion of the drum. in the application's'above referred to, provi/- sion is made for introducing air currents through the entire body of the charge, but it has been found in practice that with currents of sufficient strengt the pulverized material from the thicker portions of the mass, materials which have not been sufficiently reduced willbe carried out oflthe reducing areas or prevented from entering such reducin areas.

The object of the improvement claimed herein In the construction shown h to eiect a 'removal of is to provide for the introduction of the air currents to such portions of the charge as become loosened up and therefore more easlly penetrable, such loosening of the charge occurrin in the operation of the mill as the charge '1s carried to and moved be ond a plane coincident with thel horizonta diameter of the drum. By thus limiting the action of the air currents to the upper and less compacted portion of the charge,

it will be found that less quantities of airl moving at a lower rate -will act to efficiently remove material which has been pulverized to the desired degree of ineness.

It is a further object of the invention to provide for a separation of the particles removed from the charge in accordance Iwith the relative degree of fineness before they The inmore fully described have been removed from the mill. vention is hereinafter and claimed;

In the accompanying drawings forming a part of this specification, Fig. 1 is a sectional elevation of a mill embodying the improvements described and claimed herein and Fig. 2 is a transverse section of the same.

shell5 having its ends secured to heads 6 provided with trunnions 7, one or both of which are'made hollow for the feed of materialto be ground into the shell 5. The

The improved mill consists of a rotatable trunnions are mounted on fixed bearings' 8 and the shell is driven by a pinion 9 enaging a gear wheel 10 secured to one of the eads of the shell. The material to be treated can be fed in through either one or both of. the trunnions 7 by any suitable means known in the art, preferably suchas shown and described in application Serial No. 474079, above referred to. suitable quantity of loose grinding material or devices, such as metal balls, cobble stones, rods orbars of hard material', are charged lnto the shell or drum and operate to pulverize the material by impact and rubbing. For convenience the term balls will be used as a'generic term including thereunder any and all devices usually employed 1n such a mill.

rl`he shell 5 v1s enclosed b4 a casing .12 closelyl tting against the she l but not with sufficient closeness to revent the free rotation of the shell an providedwith enlargements 13 and 14 thereby forming chambers 15 and 16, The enlargement 13 1s so lll@ located as to extend from a plane approximately coincident with a horizontal diameter of the drum alon for a suitable distance, as for example, a little farther than the material would be carried in the rotation of the drum above thishorizontal plane. In other words the 4chamber 13 preferably extends circumferentially from about the lpoint where the charge in the shell begins to loosen up to a point a little beyond that at which the elements of the mass move away from the surface of the shell. This chamber is provided with an air inlet, which in case air at a pressure above atmospheric is employed, is connected to a fan or other air compressor. The other enlargement 14 extends preferably for about one-fourth of the circumference of the shell and is located so that the air after passing from the charge can escape through perforations in the shell into the chamber 16 from whence it is carried by any` suitable means to the point of use.

he periphery of the shell is perforated and the perforations preferably communi,-

cate with passages 17 formed in longitudinal liners' 18extending the full length of the shell. These liners are preferably constructed as shown and described in the application Serial No. 474079. As is well known in the art, the portions of the charge in a mill of this type lying in the quadrant between planes coincident with the vertical and horizontal diameters of the drum will be held closely in contact by the combined action.

of gravity and centrifugal force, andas soon as the charge passes above a plane approximately coincident with the horizontal diameter of the drum, gravity will act in a direction to cause a movement ofthe elements of the charge out of contact with each other and the inner surface of the drum, and the material will fall inwardly androll down the inner surface of the charge to the lowest portion of the drum. It will be understood that this loosening up is progressive from a plane approximately coincident with the horizontal diameter of the drum and this portion of the mass is therefore more readily penetrableby the air currents.

It is preferred that the passages directing the air into the drum should be arranged so that the air will' enter the material in a direction at an angle to the radii of the drum and preferably in a direction opposed to the direction of rotation of the shell. As the air currents escape from the charge laden with pulverized material, they will sweep down along the entire surface of the charge and then up around the inner' surface of the shell in a circular path. As the air currents carrying the pulverized material move in this circular path, they will flow across the passages 17 which have been brought by the rotation of the shell into communication with the outlet chamber 16, and on account of the difference between the pressure in the shell and chamber, some of the air will f iow through the passages; these passages being, as be ore stated, at an angle to the radii of the drum, will also be at a very acute angle to the direction of circular movement of the air in the shell so that in order to pass through these passages, the direction of movement of the air is abruptly changed, only the Very fine particles whose size will be dependent upon 'the rate of movement of the air, will pass out through these passages into the chamber 16. The heavier particles will by reason of their momentum continue along in their original direction of movement and will be brought back to the pulverizing or reducing zone.

It will be understood that this outer casing may be adjustable circumferentially as described and shown in application Serial No. 474079, so as to change the position of the inlet chamber with reference to the charge within the drum or shell. In order to insure the circular or Cyclonic movement of the air after escaping from the charge, the casing may be so adjusted that the inlet chamber will be in communication with some of the passages 17 after their discharge ends have passed a short distance beyond the upper end of the mass in the shell. The movementy of air from these unswerved passages will sweep down along the inner surface of the charge and restore currents which have been diverted in assinc through the charge to desired directions of movement.

As is well understood bythose skilled `in the art, the most effective reduction is effected while the elements of the charge are rolling or sliding down the inner surface of the mass and that reduction or pulverization over the entire inner surface is effected. lt is characteristic of the improved :manner of introducing the air currents, that the ulverized material is withdrawn from the inner portions of the charge, while in a condition facilitating such separation, and that by causing the currents to traverse the surface of the charge, the pulverized material is carried away from the area of most eflicient reduction.

The circular or Cyclonic movement of the air after escaping from. the charge may be insured by arranging an air inlet chamber 19 in the rear (relative tojthe rotation of the shell) of the outlet chamber 16. When located as shown, each passage 17 will be brought into communication with the chamber after passing beyond the outlet chamber and the air entering through such passage will flow in the same direction as the air circulating in the shell. It will be understood that the air` will enter this chamber 19 and flow through the passages under the pressure conditions ensuring Cyclonic niove- :ment of the dust laden air.

If air under pressure is supplied to inlet chamber 15 it will be supplied to chamber 19 under pressure. Provision is made for the removal of any pulverized material collecting in the lower portion of the outlet chamber 16 by connecting the latter to the chamber 19 by a valved pipe 20. The flow of air to the auxiliary chamber 19 may be regulated by a valve or damper 21.

It will be--understood that the circumferential positionof the outlet chamber is not material so long as. it is separated a sub- .stantial distance from the outlet chamber and the inlet ends of the passages in communication with the outlet chamber are not covered by any portion of the charge. It is preferred, however, that the outlet chamber be so llocated that there will be a `substantial travel of the air after passing from the charge and preferably in a circular path. The currents of air employed for removing reduced particles from the charge are produced by maintaining differences of pressure between the inlet and outlet chambers by any suitable'means known in the art, as for example, by connecting the outlet chamber 14 to an exhaust fan as shown in Fig. 1.

I claim herein as my invention:

1. A pulverizing apparatus having in combination a rotatable shell having a per-v forated periphery, balls adapted to move freely in said. shell, means for maintaining a difference in the pressure of air between such predetermined points of the shell as will cause currents of air to flow -through the shell, the air entering and leaving theshell through the peripheral perforations.

2. A l pulverizing apparatus having in combination a rotatable shell having a perforated periphery, balls adapted to move freely in said shell, a. casing having outlet and inlet chambers with which theperforations in the shell are brought into communication )successively by the rotation of the shell, and means for maintaining a difference of fluid pressure between said chambers and` thereby cause a flow of air through the shell, t 3. A pulverizing apparatus having y,in combination a rotatable shell having a perforated periphery, balls adapte-d' to move freely in said shell, a fcasing having inlet and outlet chambers with which the perforations inlthe shell are brought into communi cation successively, means for maintaining a difference of fluid pressure between said chambers whereby a flow of air through said chambers is maintained, and means for abruptly changing the direction of flow of air after passing through the charge in the shell.

4. A pulverizing apparatus having in combination a rotatable. shell provided with passages extending inwardly from the periphery of the shell and provided with ports arranged to discharge air fiowing therethrough in directions at an angle to the radii ofthe shell, and a casing having inlet and outlet chambers with which the outer ends of said passages are brought into communi cation successively on the rot-ation of the shell.

5. A pulverizing apparatus having in combination a rotatable shell provided with passages extending inwardly from the periphery of the shell and provided with ports arranged to discharge air flowing therethrough. in directions at an angle to the radii of the shell, an inlet chamber with which the passages are brought into communication in succession by the rotation of the shell and so located that such communication is established as the charge approaches the limit of the upward movement of' the charge in the shell and an outlet chamber so spaced from the inlet chamber that the passages are brought into communication therewith, subsequent to the movement of the passages from the charge.

6. A pulverizing apparatus having' in combination a rotatable' shell provided with passages extendin inwardly from the pe riphery of the shel and provided with ports arranged to discharge air flowing therethrough in directions at an angle to the radii of the shell, a casing having inlet and outlet chambers with which the outer ends of the passages are brought into communication on the rotation of the shell and an auxiliary in let chamber so constructed that the passages will be brought into communication therewith after passing out of communica tion with the outlet chamber.

7. A pulverizing apparatus having in combination a rotatable shell provided with passages extending inwardly from the periphery of the shell and provided with ports arranged to discharge air flowing therethrough in directions at an angle to the radii of the shell, a casing having inlet and outlet chambers with which the outer ends ofthe passages are brought into communication on the rotation of the shell and an auxiliary inlet chamber so arranged that the passages will be brought into communication with the outlet chamber, and a connection between the outlet chamber and the auxiliary inlet chamber.v

RALPH s. n. roMERoY.

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