US2933260A - Mill - Google Patents

Description

April 19, 1960 R. G. TEssMER MILL 2 Sheets-Sheet 1 Filed Sept. 24, 1958 R mm. NM wm m-l G. D N a m A R April 19, 1960 R. G. TESSMER MILL 2 Sheets-Sheet 2 Filed sept. 24, 195e m. m w" RAYMoNo G. ssmcn United States Patent MILL Raymond G. Tessiner, Pittsburgh, Pa., assignor, by mesne assignments, to International Process Equipment Company, Dayton, Ohio, a corporation of @hic Application September 24, 1958, Serial No. 763,168

4 Claims. (Cl. 241-171) This invention relates in general to improvements in mills and more particularly to an improved arrangement for continually venting a ball mill while the latte is in operation.

ln many processes utilizing ball mills, distinct advantages arise from being able to remove vapors etc. from the interior of the mill while continually operating the mill, or to operate the mill under vacuum. With previous designs of mills, the latter operations Were either not generally possible, or the apparatus to accomplish the same was not dependable and unduly complicated.

The present invention in general provides a ball mill comprising a body portion which is rotatably mounted on stationary supporting structure and includes venting mechanism extending into the interior of the mill and being supported on said stationary supporting structure so as to readily provide for the continuous venting of the mill while the latter is operating. A shield element is disposed in the mill interior and is mounted on said stationary supporting structure so as to prevent the ball charge and the product being handled by the mill from entering or interfering with the venting mechanism while at the same time providing for the free access of air and vapor to the venting structure.

Accordingly, an object of the invention is to provide a material handling mechanism of the ball mill type, including novel means for continuously venting the interior of the mill during operation of the mill.

A further object of the invention is to provide a ball mill mechanism which comprises a rotatable drum member mounted on stationary end supporting structure and which includes a vent or draw pipe extending from the exterior of the drum into the interior thereof and mounted on said stationary supporting structure so as to be non rotatable with respect thereto and with respect to the drum, and including shielding means for protecting the vent pipe from contact with a ball charge and/or a product being handled in the mill.

A still further object of the invention is to provide a ball mill arrangement comprising a rotatable drum member having hollow integral end trunnion portions which are mounted for rotary movement on stationary bearing structure, and including a draw-Gif or vent pipe which extends from the exterior of the drum through at least one of the end trunnions into the interior of the drum for continuously drawing oit air or vapor from the interior of the mill and/or for providing a vacuum in the mill, such vent pipe being secured to the associated stationary bearing structure so as. to be non-rotatable with respect to the drum member, and including a shield member supported at the ends thereof by said stationary bearing structure in non-rotatable relation to the drum member, and coacting with the interior surface of the drum member and with the vent pipe to prevent the ball charge and/or the product being handled by the mill from contacting or interfering with. the vent pipe, but providing free access of air or vapor to the vent pipe so that they can be continuously removed during operation of the mill.

ICC

Other features and advantages of the invention will be apparent from a consideration of the following description taken in conjunction with the accompanying drawings wherein:

Fig. 1 is a partially sectioned, side elevational view of a ball mill mechanism embodying the instant invention;

Fig. 2 is an end elevational view of the mechanism of Fig. l taken from the right hand side of the latter figure;

Fig. 3 is a vertical sectional view taken generally along the plane of line 3-3 of Fig. l looking in the direction of the arrows.

Referring again to the drawings, there is illustrated a material handling mechanism of the ball mill type comprising a supporting frame structure 10 onto which is mounted a rotatable hollow body or drum 12. Drum 12 is provided with suitable covered openings (not shown) for charging and discharging of the balls and product being handled. Member 12 includes end wall portions 12a and 12b, from which project integral trunnion portions 14. 'Ilrunnion portions 14 are hollow and open into the interior of the drum member for a purpose to be hereinafter described in detail. Trunnion portions 14 are rotatably mounted on pedestal elements` 16 secured to lframe Iii. Bearings 18 of conventional type are provided on pedestals 16 to provide anti-frictional rotational movement of the trunnion portions 14 upon rotation of drum 12. Drum 12 is driven in conventional manner by means of a motor unit 20 mounted on frame il? in conjunction with gearing mechanism 22.

ln accordance with the invention, vent or draw pipe mechanism 24 is disposed inthe interior of the drumr member 1i2 and extends generally lengthwise thereof to the exterior of the drum. Vent pipe 24 is apertured for receiving vapor and/or air from the interior of the drum and carrying it to the exterior thereof and in?Y cludcs a dust filter member 24a for cleaning such vapor or air during its passage into and through vent mechanism 24. In the embodiment illustrated, the lengthwise or horizontally extending internal portion 2S of vent` pipe 24 does not extend the full length of drum 12 butis terminated as at 25a before reaching the vicinity of` end wall 12b of the drum. The other or outer end off portion 25 of vent 24 is bent downwardly adjacentend wall 12a to form a generally vertically extending duct portion 26 which, at its lower end, is connected to horiz` zontally extending outer duct portion 28. It will be seen therefore, that vent mechanism 24 has a stepped or Z shaped conguration in side elevation. lPipe or duct portion Z has a tting 28a mounted thereon for attachment to a pump or other mechanism for drawing of the air and/or vapor in the drum member 12 through the,

passageway formed by duct portions 2S, 26 and 28. Vent duct mechanism 24 is maintained in a predetermined stationary position by bracket structure 3th suitably secured to frame 10. Duct portion 28 is supported in antifrictional relation on the interior surface of the associated.

of the trunnion members 14 by means of conventional` bearings 32 which are diagrammatically illustrated. Suit-` member 12.` Duct 36 may be for the purpose ofA receiving instrumentation or for supplying air or some. other media into the interior ofthe rotary drum member 12 rof thepmill.

Within the rotatable shell or drum member 12, is disposed a shield element 46 for protecting vent structure 24 against the ball charge and/or the product disposed in the drum during operation thereof. Shield 40 comprises a body portion 42 and end supporting portions 4a and 45. While a supportingV portion is shown on either end of the bo'dy portion of the shield, it willbe understood that the latter could be so constructed so as to be supported at only one end thereof. End portion 44'which is disposed adjacent end wall 12a of drum 12 is supported on or by fixed duct portion 28 of vent structure 24, while the other 45 of the end portions, which is` disposed adjacent end Wall 12b of the drum 12, may be supported on a stationary shaft or supporting member in a generally similarmanner as aforedescribed in connection with end portion V44,. It will be seen, therefore, that shield di)` is nonrotatable with respect to the associated drum member 12. The body portion 4Z of the shield commences adjacent-the t'op of drum 12 incomparatively closely disposed relation therewith, and curves downwardly in a sharper arc than does the confronting interior surface of the drum, to thereby define a widened bottomed passageway 47 (Fig. 3) for the generally free access of vapors and/or air to the vent structure 2.4. The body portion of Vthe shield 40 is provided with a lengthwise extending recessed or hollowed portion 48 (Fig. 3) for receiving in complementary supporting relation the duct section 25 of vent structure 24. As is illustrated in Fig. 3 of the drawings, theshell or drum member 12 of the mill is adapted to rotate in the direction of the full line arrow A thereby causing the ball charge and product B being handled or processed by the mill to pile up or occupy the generally right hand side (as viewed in Fig. 3) of the drum. lt will be apparent that shield 40 will effectively prevent any of the ball change or product being handled or processed from striking or enteringthe vent pipe 24 and yet the vaporand/or air in theinterior of the mill may readily rise or pass through passageway 47 dened by the shield. 40 and contronting interior surface of dlum 12, and as is illustrated by the dot-dash arrows in Fig. 3, to the vent structure 24. It' will also' be seen that the end portion 44A of shield 40Vis generally molded or bowed around vertical duct section 26 of vent structure 24, and thusprotects the latter section from injury, `due to the tumbling or moving ball charge and product in the mill interior. Portion 44 also prevents the charge from passing into duct 36 while still permitting atmospheric communication between the interior of the mill and duct- Work 36.

' The Qven'ting and shielding mechanism occupies a minimurnof operating space interiorly of the mill and does not interfere in any manner with the mills functioning. In this connection, it will be Seen thatV the venting apparatus 25, is inclined away from the vertical longitudinal center plane of the mill in the direction of rotation thereof `(Fig. 3), to thereby occupy generally non-operating space in the interior of the' mill.

A mill of the above construction may be used as a chemical reactor where vapors must be removed during operations, or it may be operated under vacuum, for example to assist in the removal of occluded gases from the product, or the product being processed in the mill could beY charged in the form of a slurry mixed with a solvent which could then be vaporized by suitable means such as the iauxiliary heating jacket 50 encircling the exterior of the ball mill, andY removed through the vent structure 24 so that the product being handled could be better ground dry, after which the solvent removed could then be reintroduced into the mill interior to reslurry the product prior to' discharge thereof. As may be seen in 1, suitable piping 52 andassociated rotary union connector may be provided for furnishing the heating medium to jacket 50.v Another environment in which the ball could be advantageously utilized would be under the condition where it was desirable to evacuate the mill interior and back-fill with an inert atmosphere, prior to l4 the introduction of the product, to avoid a non-desirable atmospheric reaction. It will be seen, therefore, that various combinations of the above operations could be employed to obtain any desired end result. While the coniiguration of the ball mill illustrated has been of generally cylindrical shape, it will -be understood that other designs of rotatable shell members could be utilized in conjunction with the venting and shield arrangement shown, so as to provide for continuous venting of the mill interior during operation of the mill, and without interference with the said operation thereof. The shield and vent arrangement is compatible with alloy metal as well as with ceramic lined mill constructions.

From the foregoing description and accompanying drawings, it willbe seen that the invention provides a material handling mechanism of the ball mill type, which includes venting structure forcontinuously venting or drawingoff the Vatmosphere interiorly of the mill during operation thereof and in combination with shield structure for protecting such venting mechanism from thc charge being handled in the mill. ln addition, the invention provides a mill structure which is adaptable for use in a great variety of conditions and operations where it is necessary or desirable to introduce or remove media into or from the interior of the mill, thus greatlyV enhancing the useability of the mill, such operations being performable during operation of the mill. Y

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of any of the features described or shown or portions thereof, but it is recognized thatvarious modications are possible within the scope-of the invention claimed.

- 1. vIna ball mill comprising a supporting frame, a shell member Amounted on said frame for rotation'about a generally horizontallyrextending axis, said shell member being adapted'to receive a charge of balls and product therein tobe processed, elongated venting means disposed in VVsaid shell member and extending exteriorly thereof generally along the axis of rotation of said shell member, said venting means being mounted in stationary relation with respect to said supporting frame and being disposed v generally adjacent the interior surface of said shell member, said venting means comprising an elongated upper section extending generally horizontally interiorly of said shell member and a generally downwardly projecting section nteriorly of said shell member and communicating .with one end of said upper section, said downwardly projecting' section-extending generally transverse to the axis of rotation of said shell member and communicating at its lower end with another venting section extending exteriorlyl of said shell member along the axis of rotation thereof, and shielding means coacting with'said venting means to prevent the charge of balls and product from direct contact with said venting means, said shielding means being mounted in stationary relation with respect to said supporting frame and comprising a body portion of arcuate shape in vertical sectionextending generally parallel to and in juxtaposed relation to said upper section of said venting means, said shielding means iucludng at least one downwardly extending end portion supporting said body lportion in spaced relation to the axis ofrotation of said shell member, said venting means being disposed intermediatethe interior surface of said shell member and sadshieldingrmeans to thereby .protect said venting means from directfco'ntact with the'charge, said end portion being bowed outwardly and disposed in protecting relation about 'saiddownwardly 'extending section of said venting means. j' f 2. In a ball mill in accordance with claim 1, whereinv said body portion of said shielding means has a lengthwise, recess disposed therein and receiving in complementaryA suppo'rting relation said upper section of said venting means.

3. In a ball mill comprising end supporting structure, a hollow drum member mounted for rotation on a generally horizontal axis extending between said end supporting structure, said drum member being adapted to receive therein a charge of product to be processed and grinding balls for accomplishing the same, the end walls o'f said drum member having axial and outwardly extending trunnion portions secured thereto, at least one` of said trunnions being hollow and open at both ends thereof, vent means extending from the exterior of said drum member into the interior thereof, said vent means comprising a generally step-shaped duct, one section of which extends axially through said one trunnion portion and another section of which extends lengthwise in the interior of said drum member generally adjacent the inner periphery thereof and parallel to the axis of rotatio'n of said drum member, said sections being connected by a generally vertically extending section which is angularly displaced from the longitudianl vertical center plane of said drum member in the direction of rotation thereof, means disposed intermediate said one duct section and the interior o'f said one trunnion portion to prevent leakage from thel interior of said drum member, means for holding said vent means in stationary relation on the associated of said end supporting structure, and shielding means dispo'sed nteriorly of said drum and coacting with said vent means to prevent engagement of the charge with said vent means during rotation of said drum, said shielding means comprising a generally lengthwise extending body portion adapted to be disposed intermediate the charge and said vent means and at least one end portion connected td said one duct section of said venting means and supporting said shielding means in stationary relation to said end supporting structure, said body portion of said shielding means being of arcuate configuration in vertical section with the center of curvature thereof being disposed in spaced relation to the center of curvature of the interior surface of said drum member, said body portion cornmencing adjacent the top of the drum interior and curving downwardly and away from the confronting interior surface of said drum member to define a widened bottom passageway for the free access of vapors to said vent means.

4. In a ball mill in accordance with claim 3, wherein said one section of said vent means comprises an auxiliary duct disposed in telescoped relation nteriorly thereof, said auxiliary duct at its inner end being in communication with the interior of said drum member and at its other end projecting exteriorly of said one section.

References Cited in the le of this patent UNITED STATES PATENTS 1,690,712 Bonnot Nov. 6. 1928 2,507,917 Lonnegren May 16, 1950 FOREIGN PATENTS 17,712 Great Britain of 1911 506,490 Germany Sept. 4, 1930 570,515 Germany Feb. 16, 1933

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