US2760727A - Process and apparatus for vibratory grinding - Google Patents

Description

28, 1956 s. KIESSKALT 2,760,727

PROCESS AND APPARATUS FOR VIBRATORY GRINDING Filed May 24, 1951 $1 INVENTOR. 7fY/ed ags 421/1;

PROCESS AND APPARATUS FOR VIBRATORY GRINDING Siegfried Kiesskalt, Hannover, Germany, assignor to N. V. Tema, The Hague, Netherlands, a corporation of the Netherlands Application May 24, 1951, Serial No. 227,994

Claims priority, application Germany May 25, 1950 2 Claims. (Cl. 241-27) The comminuting machines, known as vibrating mills are constructed as mills with a horizontal vessel, trough or receptacle, provided with auxiliary grinding bodies in the shape of balls, rolls, etc., and they are brought to a quick circular or elliptical oscillation. This causes the grinding bodies to inflict quick mechanical impacts on each other, upon the interior of the mill and upon the material to thereby size reduce the material.

It is an object of the present invention to improve the operation of such mills and thereby remove various disadvantages therein.

With the above and other objects in view which will become apparent from the following detailed description, some preferred modifications of the process are described and shown in the drawings in which:

Figure l is a diagrammatic showing of a vibrating mill.

Figure 2 is a diagrammatic view illustrating the movement of the contents of the mill in one direction.

Figure 3 is a view similar to Figure 2 showing the movement of the contents of the mill in the opposite direction, and

Figure 4 shows diagrammatically a shape of a mill which is very favorable for the application of the process.

Referring to Figure l, a cylindrical vessel is shown at 1 with a shaft 2 located within a shaft protected tube 3. The vessel is suspended upon the springs 4 and when vibrated Will cause a closed path oscillation in the direction of the arrow upon the circle 5 located above the figure. The balls 6 serving as the grinding bodies and material being treated travel in an opposite direction as shown by the arrow 7 and in this way the device of the material is reduced. The contents of the mill may then take a sloping position as indicated at 8.

The above process has some disadvantages. Local and one-sided deposits often occur and moreover often are caked together as a solid mass which is outside of the grinding action. Moreover, especially in wet grinding, some of the spattered material may be located within the free space 9 Where it may be attached to the wall of the vessel and thereby prevent any accurate fine grinding thereof.

The present invention removes the above-mentioned disadvantages by vibrating the mill for a relatively long period, as for example from ten minutes to an hour, alternately in a different oscillation direction, i. e., alternately clockwise and counterclockwise.

Figures 2 and 3 illustrate the respective movements schematically. The oscillations are shown as counterclockwise in Figure 2 and clockwise in Figure 3. The contents of the mill which are shown latched in Figures 2 and 3 travel as shown in each figure by the direction of the arrow. In Figure 2 the highest point of the travel of the material is located at 10 and in Figure 3 at 11 against 2,760,727 Patented Aug. 28, 1956 quencies of the elastic suspension with big irregular amplitudes, and the contents of the mill, consisting of grinding bodies and material are mixed with forcible impacts and a loosening and comminuting also of solid deposits or caked layers takes place.

Two consecutive periods according to the invention need not last equally long. Especially in geometrical asymmetrical grinding vessels, such as one sided passing troughs, the periods with the most favorable direction of oscillation will be chosen longer, e. g. one hour, the consecutive looseningand free-grinding period, however, only ten minutes.

The interval of impact lying therebetween, gives nevertheless the desired result. The reversion itself may take place adjustably mechanically or electrically by known devices.

A vessel shape which is extremely favorable for the application of the process according to the invention is shown in Fig. 4, in which 12 represents the periphery and 13 the contents of the mill with the direction of revolution shown by snow 15 corresponding to the direction 14 of the path drawn in full line above it. The upper part of the vessel consists here of two, more or less heart shaped arcs 16 and 17, passing one into the other, the radii of which correspond roughly with half the radius of the lower part of the vessel. If the direction of oscillation is reversed according to the second circle 18, shown in dotted lines above Fig. 4, the material to be ground takes, with the direction of rotation shown by arrow 19, in the vessel 12 the slope which is partly shown in dotted lines. In this way the entire inner wall of the grinding vessel is scraped.

It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the process without departing from the spirit and scope of the invention or sacrificing its material advantages, the process hereinbefore described being merely a preferred embodiment of the invention.

I claim:

1. A grinding vessel for a vibrating mill containing grinding bodies which is brought to a quick circular or elliptical oscillation thereby causing said bodies to inflict mechanical impacts upon one another comprising a trough shaped lower part and an upper part having a heart shaped outline.

2. In a grinding process for size reducing wet or caking types of material in a vibrating mill consisting of a horizontal vessel loaded with grinding bodies and material to be disintegrated, wherein the mill with load is oscillated and brought to a quick circular or elliptical closed path oscillation, thereby causing said bodies to inflict mechanical impacts upon each other, upon the interior of the mill and upon the material to thereby size reduce the material, the improvement comprising periodically reversing the direction of oscillation at periods of from 10 minutes to an hour, to scrape a maximum surface of the interior of the vessel and to loosen and comminute any materials which tend to cake thereon.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Dodge Aug. 15, 1882 Ney Mar. 16, 1915 5 Jacobson Apr. 12, 1921 Schomo Mar. 6, 1923 Crites Nov. 10, 1925 Friedman "Mar. 30, 1926 4 Osgood Aug.- 1, 1939 Links July 16, 1940 Earle Feb. 25, 1941 Kiesskalt Aug. 4, 1942 Winslow Sept. 28, 1948 FOREIGN PATENTS Germany Jan. 11, 1921

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