US2241848A - Apparatus for preparing very fine lustrous metal particles - Google Patents

Description

May 13, 1941.

J. ECKART 2,241,848 APPARATUS FOR PREPARING VERY FINE LUSTROUS METAL PARTICLES Filed Jan. 20, 1938 2 Sheetsl-Shet 1 lm/enfantfaaZ 5: kg r Z B May 13, 1941. J, KART 2,241,848

APPARATUS FOR PREPARING VERY FINE LUSTROUS METAL FARTICLES Filed Jan. 20, 1958 z Sheets-Sheet 2 Inventor:

- Lzco5 Zeke/'2 By Patented May 13, 1941 APPARATUS FOR PRE LUSTROUS MET PARING VERY FINE AL PARTICLES Jacob Eckart, Furth, Germany, assignor to the firm Standard Bronzefarben Werke Carl Eckart, Furth, Bavaria, Germany Application January 20,

1938, Serial No. 185,963

In Germany October 14, 1935 12 Claims.

My invention relates to an apparatus for preparing very fine highly lustrous metal particles, such as are required for making bronze paints and metal powder.

The apparatus consists of a combined ball and hammer or beating mill in which the Working 'material consisting of small platelets is beaten thin and smooth. The end product consists of scales of the maximum smallness and thinness having a smooth, highly lustrous surface.

On the combined ball and hammer mill there is an arrangement by means of which a continuous equalisation of the inner air and the outer air is made possible. By means of the air equalisation a slow, harmless oxidation of the working material is brought about during the working process.

The accompanying drawings show one constructional example of the apparatus according to the invention. In the drawings Figure 1 shows the combined ball and hammer mill in elevation,

Figure 2 shows an end view of the mill,

Figure 3 shows a section through the wall of the mill at the place where the air equalisation occurs,

Figure 4 shows a diagrammatic cross section through the mill, and

Figure 5 gives a schematic representation of the hammer motion in the cross section of the mill.

The combined ball and hammer mill consists of a drum a which accommodates rolling balls 72. of varying size. Throughout the length of the drum there are anvil elements It on which at least one hammer g falls when the drum rotates.

In Figures 4 and 5 the arrangement, and manner of working, of a hammer g is shown schematically. The hammer operates alternately on three anvil elements k, which latter, arranged in triangular form, are fixed within the drum (1 and rotate with the drum. The hammer g is rotatably or pivotally suspended at the point f. The point 1 is outside the middle axis of the drum a and is stationary, and therefore does not partake of the rotation of the drum. Thus the center j which is the pivot point of suspension for the hammer g is immovable or stationary with respect to the rotating drum a and each anvil leis at the same distance from the axis center of the drum a. In a preferred form of the invention of construction the hammer g is suspended from a point 1 on a link I, Fig. 4, and this link is keyed or otherwise suitably secured on the center point or shaft f". The shaft j" is stationary at all times and the drum a rotates around the shaft ,f" as an axis, I

When the hammer g, as shown in Figures 4 and 5, rests or contacts on one of the three anvil elements k, then, while the drum 0. is rotating counterclockwise in the direction of the outer arrow,

the hammer is taken along by the anvil element,

reached a position where itis in the path of the descending hammer.

The interior space of the drum a is only partly filled with the working material. At the moment at which the hammer g falls on to the next anvil element lc, hammer and anvil element are both within the working material. That portion of the working material, therefore, which lies above or in the path of the impact surface of the anvil element, is beaten by the descending, hammer.

The balls h' are always situated within the working material and are caused to roll about by the rotation of the drum. slowly. As a result the balls are not raised so high that they could fall down freely. The balls roll about in the working material but they do not fall down on to the material in the drum to be worked.

By the simultaneous action of the hammer g and of the balls 11. the working material is reduced in size and texture. The working process is finished when the small platelets which form the starting material are converted into smooth highly lustrous scales of the greatest fineness and thinness.

As is shown in Figures 1 and 2, a pipe b leads into the mill a. Through this pipe fresh air is led into the drum. At one place in the drum wall a number of holes or perforations c are arranged. The perforated place is covered in the interior with a filter cloth d. On the filter cloth there lies in the interior a perforated plate e. The holes or perforations j of the plate e correspond with the holes c in the wall of the drum.

The holes 0 and ,f effect a continuous equalisation between the inner air and the outer air during the working process. As a result of the shaking which the drum experiences during the working process, the material being ground is continuously shaken away from the holes j-c so that the said holes remain free for the passage of air. The filter cloth d permits the passage of air The drum rotates Owing to the mechanical heating of the working material a slow temperature rise takes place in the operating ball and beating mill. By means of the continuous air equalisation, a temperature rise up to the ignition temperature of the working material is prevented. A gradual, slight and harmless oxidation takes place at the surface of the small metal particles. In this way, explosion in the interior of the working mill is prevented.

I claim:

1. An apparatus for making very fine, lustrous metal particles, comprising a rotatable drum, at least two anvil elements fixed in circumferential spaced relation relative to each other within the drum to rotate therewith around the center axis of the drum and each element being spaced a substantial distance from the peripheral Wall of the drum and the axis of rotation of the drum, each anvil element having a fiat impact surface in a plane approximately parallel to the axis of rotation of the anvil elements and a side surface of each element facing the axis of rotation being directed rearwardly from its impact surface to clear the path of movement of the hammer, and

. a hammer suspended to swing in the drum from a fixed point which is spaced below the longitudinal center axis of the rotating drum and is adapted to successively strike the impact surface of each anvil element, the suspension distance of the hammer being less than the radial distance of each anvil element and said hammer after striking one of the anvil elements being carried along by said last-mentioned element in the direction of rotation of the drum but due to the off-center suspension of the hammer it is gradually pulled off from the last-mentioned element until it clears the edge of its impact surface whereupon the hammer follows an unrestricted movement in the direction counter to the direction of rotation of the drum and falls and strikes the impact surface of the following or other anvil element.

2. An apparatus according to claim 1 in which each anvil element is wedge shaped with the wedge portion extending rearwardly of the impact surface and arranged parallel to the longitudinal axis of the drum.

JACOB ECKAR'I'.

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