US3272443A

US3272443A - Vibratory mill

Info

Publication number: US3272443A
Application number: US448574A
Authority: US
Inventors: Reiners Ewald; Otters Erich
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-02-22
Filing date: 1965-04-09
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13
Also published as: GB959652A; DE1214517B

Description

Sept. 13, 1966 E. REINERs ETAI. 3,272,443

VIBRTORY MILL Original Filed Feb. 21, 1963 2 SheetsSheet l INVENTORS Ewald Reiners, Em'ah Wiens sept 13, 1966 E. RElNERs ETAL 3,272,443

VIBRATORY MILL Original Filed Feb. 2l, 1965 2 Sheets-Sheet 2 Z7 INVENTORS4 Z6 Ezmal Reiners,

/5 BY l l I Z 3 mpg' A'ORNEYS United States Patent() 3,272,443 VIBRATRY MILL Ewald Reiners, Hinsbeckerberg 44, Essen, Germany, and

Erich Otters, Aachen, Germany (Friedenstr. 87, Duisburg, Germany) Continuation of application Ser. No. 260,153, Feb. 2l, 1963. This application Apr. 9, 1965, Ser. No. 448,574 Claims priority, application Germany, Feb. 22, 11962, S 78,163 16 Claims. (Cl. 241--1530 This application is a continuation of US. patent application Serial No. 260,153, filed February 2l, 1963, now abandoned.

The invention relates to continuously operating vibrating or oscillating mills which are resiliently mounted to allow free displacement thereof and which are forced to describe gyratory vibrations by a suitable vibratory generator.

Vibrating mills are known in which two milling boxes, lying one upon another or side by side, are rigidly associated to provide a screening system that is secured to a base by supporting springs. The required vibratoiy motions are produced by a generator of centrifugal forces arranged at the center of gravity of the system, the amplitude of the oscillations being dependent upon the magnirude of the centrifugal force generated.

There are also known oscillatory mills that consist of two symmetrical milling systems of equal size. In this case one system is secured to a base by supporting springs and is resiliently connected to the second system in such a way that both systems are capable of describing circular oscillations which are in phase displacement to each other by 180. The vibrating means positioned in a central tube is rigidly connected with one of the two systems.

In such known oscillatory mills the material to be milled traverses the milling boxes in a horizontal direction said, in the case of milling boxes positioned one above the other, it is always caused to issue into the next box beneath. The discharge openings of the upper milling box are connected by means of flexible hoses with the inlet openings of the lower box. Thus, in the case of milling boxes that lie side by side, there are always millings groups connected in parallel. The total length of all the milling boxes can be utilized only partially as a milling path. The excessive number of flexible hoses increases the number of possible leakage points. The milling boxes being rigidly connected with one another are not interchangeable or are interchangeable only if small tolerances are permitted in the construction thereof. But even in cases such as this, such interchange can be quite expensive; the openings and connecting flanges must also be interchangeable. The boxes are therefore provided with means to protect them against wear and tear which greatly increases the weight of the oscillating parts.

The adjustment of the spring elements in the known vibratory mills has been found, in practice, to be very troublesome. The resiliently supported masses are so great as to require a large spring volume. Also, the subsequent installation of a cooling arrangement capable of directly cooling the walls of the boxes that contact the material undergoing milling, involves many difiiculties. For this reason the applicability is largely confined to the milling of materials that are not affected by heat.

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The object of the present invention is the avoidance of the drawbacks that attend the use of known vibratory mills. A further object of the invention is the provision of improved mills of the aforesaid type. This particular improvement lies in the fact that milling boxes have been devised that are cylindrical in cross section and are held with their front ends in side pieces that are rigidly connected with one another. These side pieces are formed in such a way as to jointly enclose the front ends of the milling boxes. By a suitable subdivision of the side pieces into separate chambers, which can optionally communicate with each other through openings that can be closed, it is possible to move the material being milled, as one chooses, either horizontally or vertically to the next milling box. Another advantage realized is the control of the residence time in the mill, thus avoiding hold-up of material and .the formation of dead spaces. By suitably securing the milling boxes in the side pieces-preferably with the aid of clamp connections-and by locating the inlet and outlet openings in the side pieces, the milling boxes will consist only of plain pipe sections of commercial type, which are readily exchangeable. This obviates, in many cases, the use of special protective measures against wear and tear. The boxes may be turned as desired so that the wear and tear is distributed over Ithe whole circumference, thereby materially prolonging the useful life of the mill. If sleeved springs of a resilient material are used for supporting the milling boxes it is possible to provide not only a large clamping connection without tolerance limitations but, in addition to this, a vibratable multimass system wherein one mass is divided into several single masses. By appropriate adjustment of the sleeved springs there is created a vibrating system that can work in resonance in which the required vibration generating forces and, therefore, also the load ranges, are smaller than in the case of a single-mass system. The resilient sleeved springs permit the subsequent building-in of cooling jackets for the milling boxes; as they are capable of preventing the escape, not only of the material being milled, but also of cooling fluid. All parts are easily interchangeable.

The installation of friction bearings of special design makes it possible to construct vibratory mills of larger dimensions operating at higher speeds of oscillation and having a substantially increased working life. The eccentricities required for creating the centrifugal force are installed only upon completion of the construction in the generator shaft which is in the form of a tubular shaft, thus permitting a lowering of the construction costs. The cylindrical form of the generator shaft, moreover, reduces the air resistance and consequently the propulsive output.

The following description sets forth an embodiment of the invention with reference to the accompanying drawings in which:

FIG. 1 is a sectional view taken through the milling boxes and the means for generating the vibrating motion of the mill;

FIG. 2 shows a transverse section through the side pieces of the mill, and

FIG. 3 shows one exemplified embodiment of the supporting system for the milling boxes.

In FIGS. 1 `and 2 there is shown a diagrammatic View of a continuously operated vibratory mill having 4 milling boxes. Two box-like side pieces 1 and 2 are rigidly connected with one another by means of a central pipe 3.

They are mounted on a base with the aid of supporting springs 4. The side pieces are divided into separate chambers by partition walls 5 to 8, said chambers being in communication with each other upon removal of the covers 9. The side pieces are provided with inlet openings and outlet openings 11. The milling boxes 13 are inserted through the installation opening 12. The mounting support is provided by sleeved springs 14 which lare modified by the box covers 15 and by the tightening of the movable flange 16 in such a way that aside from forming a seal that is airtight and impervious to dust there is insured a sufficiently rigid connection between the milling boxes and the side pieces. The lower part of box covers 15 are grate-shaped. The upper part of the covers are provided with charging ports 18 that are closed by covers 17.

The tubular shaft 19, which is installed in the central pipe 3, is driven by a motor (not shown) through a coupling 20. The shaft turns in friction bearings 21 which are preferably in the form of hydrodynamically lubricated multi-surface friction bearings. The shaft itself is fashioned as a tubular shaft wherein the cylindrical hollow space 22 is subdivided by a longitudinal partition wall 23. One half of the hollow interior is filled with a specically heavy substance 24 that serves as the eccentric weight.

The milling boxes 13 are filled with auxiliary grinding bodies such as balls or the like through charge ports 18. The admission of the material to be milled is effected selectively through feed pipe 10 emptying in the first closed chamber and from the latter through openings in the lower part of box cover 15 into the rst milling box. The material to be milled travels lthrough the box in a horizontal direction and arrives from the chamber located at the end into the next chamber beneath or adjacent it, from where it continues in its transit to the next milling box. The material undergoing milling can either traverse consecutively all the milling boxes or only those that are superposed, which makes it possible, in the case Of a multiple feed of material, to form milling groups working in parallel relationship which milling paths are shortened and the output is increased. Thus, the mill is capable of meeting, better than with the means heretofore available, the requirements with respect to liness and output.

FIG. 3 shows in section a further advantageous form of a mounting support for the milling boxes. Between the milling boxes 13 -and the

flanges

25 and 26, on the one hand, and the box cover 15, on the other hand, there are provided

spacings

27 or 28. By prestressing the anges and 26, which are suitably displaceable with respect to each other, the sleeved spring 14 encloses the milling box with an initial stress such that the box is able to vibrate in a direction transverse to its longitudinal axis.

The centrifugal force of generator 19 compels the side pieces that are connected by the central pipe to describe gyratory vibrations which are transferred by the sleeved springs 14 to the milling boxes 13. In the vibrating multimass system, upon suitable adjustment of the operating frequency to the inherent frequency of the system, the oscillation amplitudes of the milling boxes will be greater than those of the generator means.

Two each of oppositely positioned flanges 25 may, if necessary, be connected together by means of a tubular shell 29. This forms a cooling space 3i) which is closed by the `double-acting sleeved springs 14. As a result of this it is possible to provide a high degree of cooling of the milling box, whereby the heat transfer is not impeded by protective means against wear and tear.

What is claimed is:

1. A vibrating mill including a plurality of generally parallel milling boxes arranged concentrically about a central axis, two end frames, the ends of the said milling boxes being positioned in and carried by the two said end frames, each end frame having a plurality of compartments therein, each compartment being in communication with a .single one of the said plurality of milling boxes, and selectively in communication with each other, whereby the material milled can be selectively conducted to a neighboring milling box, such that the residence time of the materialv in the milling boxes can be chosen on the basis of the ultimate neness desired, at least one inlet orifice on at least one end frame communicating with one of the said compartments, at least one outlet orice on at least one end frame communicating with another of said compartments.

2. The vibrating mill of claim 1, wherein said cornpartments are box-like and are defined by walls within said end frame, said walls having parts therein selectively operable and closable to thereby establish communication between adjacent compartments.

3. The vibrating mill of claim 1, wherein the said milling boxes are tubular with the longitudinal axes of the tubular boxes being parallel to the said central axis.

4. The vibrating mill of claim 1, wherein the ends of the said milling boxes are held by a clamping connection providing a resilient gas and liquid impervious joint between the milling boxes and the compartments with which they communicate.

5. The vibratory mill of claim 4, wherein the clamping connection is effected by means of a resilient circumferential ring.

6. The vibratory mill of claim 1, including resilient circumferential means for holding the ends of the said milling boxes and permitting rotating of the boxes about their lengthwise direction.

7. The vibrating mill of claim 1, wherein the end of each milling box is colsed by end pieces, each end piece having a grate at the lower portion thereof and having a selectively openable and closable aperture at the upper portion.

8. The vibrating mill of claim 1, including energizable means carried by the mill for vibrating it in directions transverse `to the said central axis.

9. The vibratory mill of claim 8, wherein the said energizable means comprises an elongated and rotatable cylinder extending between the end frames and mounted on a shaft, the said shaft journaled on bearings, the said bearings being connected to the said end frames, the said cylinder being divided by a partition thus defining a closed volume within the said cylinder, the said closed volume being eccentrically located with respect to the said central axis and containing a heavy mass that serves as the eccentric weight.

10. The vibratory mill of claim 9, wherein the said bearings are hydro-dynamically lubricated multi-surface friction bearings which are lubricated by constant circulation oiling.

11. The vibratory mill of claim 1, wherein the end frames are compar-tmentwise symmetrical.

12. The vibratory mill of claim 1, wherein at least one of the said milling boxes is at least partially surrounded by a jacket spaced from the exterior surfaces thereof to define a chamber for the introduction of a coolant.

13. The vibratory mill of claim 8, wherein ysaid energizable means is a hollow shaft subdivided by a wall, such that substantially one half of the hollow space is iilled with a mass serving as an eccentric weight.

14. The vibrating mill of claim 1, wherein said plurality of milling boxes is comprised of a first upper group and a second lower group, at least one end frame having `a said inlet orifice for each of said compartments communicating with one of said milling boxes of said upper group, and at least one end frame having a said outlet orifice for each of said compartments communicating with one of said milling boxes of said lower group.

15. The vibrating mill of claim 1, wherein said plurality of milling boxes is comprised of a rst upper group and a second lower group, each of said end frames having a said inlet orifice for each of said compartments communicating with one of said milling boxes of said upper References Cited bythe Examiner group, and each of said end frames having a said'outlet UNITED STATES PATENTS orifice for each of said compartments communlcatmg with one of said milling boxes of said lower group, 1,951,823 3/1934 EPPefS 241-137 16. The vibrating mill of claim 3, including resilient 5 2,760,729 S/ 1956 Mittag 241-137 circumferential means for holding the ends of said milling 2,937,814 5/ 1960 J oisel 241-137 boxes, and said milling boxes being tubular, whereby the cooperation between said resilient means and the tubular ROBERT C. RIORDON, Primary Examiner.

shape of said boxes permits readily substituting one box for another, lo H. F. PEPPER, JR., Assistant Examiner.

Claims

1. A VIBRATING MILL INCLUDING A PLURALITY OF GENERALLY PARALLEL MILLING BOXES ARRANGED CONCENTRICALLY ABOUT A CENTRAL AXIS, TWO END FRAMES, THE ENDS OF THE SAID MILLING BOXES BEING POSITIONED IN AND CARRIED BY THE TWO SAID END FRAMES, EACH END FRAME HAVING A PLURALITY OF COMPARTMENTS THEREIN, EACH COMPARTMENT BEING IN COMMUNICATION WITH A SINGLE ONE OF THE SAID PLURALITY OF MILLING BOXES, AND SELECTIVELY IN COMMUNICATION WITH EACH OTHER, WHEREBY THE MATERIAL MILLED CAN BE SELECTIVELY CONDUCTED TO A NEIGHBORING MILLING BOX, SUCH THAT THE RESIDENCE TIME OF THE MATERIAL IN THE MILLING BOXES CAN BE CHOSEN ON THE BASIS OF THE ULTIMATE FINENESS DESIRED, AT LEAST ONE INLET ORIFICE ON AT LEAST ONE END FRAME COMMUNICATING WITH ONE OF THE SAID COMPARTMENTS, AT LEAST ONE OUTLET ORIFICE ON AT LEAST ONE END FRAME COMMUNICATING WITH ANOTHER OF SAID COMPARTMENTS.