US1621270A - Process of and apparatus for obtaining powders of great fineness - Google Patents

Description

March 15 1927. 1,621,270

E, PODSZUS I PROCESS OF AND APPARATUS FOR OBTAINING POWDERS OF GREAT FINENESS Filed Sept. 2, 192.4

Patented Mar. 15, 1927, Q

UNITED. STATES I 1,621,270 PATENT OFFICE.

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PBjOOESB AND APPARATUS FOR OBTAINING POWDEBB 0] exam IINENESB;

Original application filed July 1, 1022, Serial No. 572, Divided and thilal'mllcltlon filed September 2, 1824, Serial No. 785,253, and in Germany July 12, 1921.

My invention has reference to a method and a means for effecting the comminution and disintegration of materials and substances of any kind, particularly of metals, with a view to obtaining owders of extreme fineness which may e increased to colloidal dispersion, such as described in my application for Patent, Ser. No. 572 340, filed on July 1, 1922, of which this app ica-- tion is a division.

As has been stated in my said application, very fine powders can be obtaine in this way, that in a closed casing very rapidly circulating whirling air -or gas currents are -produced moving at a velocity of several thousand times, or more, per minute. By

' ,these currents the particles of the material to be treated are carried along and caused to continually impinge upon eachother, and an especially ood abrading effect is obtained, if the w 'rling currents not only iminge upon each other in a rectilinear path, but aregiven also a lateral movement. I In the further evolution of my process, it is possible to still further considerably increase the degree of fineness and to obtain in a comparatively short time large quantities of powder of colloidal fineness. This is due to the fact that with the process" described in in said application, a certain state of equili rium occurs after some time, in which even after prolonged grinding, any appreciable comminution can no longer be obtained. This state of equilibrium terminates in the case of coarser particles in the ratio of lightness of weight of the material in view of the fact that the mass of individual particles impinging upon each other, is gradually reduced to such an extent that any appreciable progress in the disintegratin operation becomes impossible.

n accordance with the present invention therefore, fine particles are submitted to the comminuting operation accompanied by considerably coarser particles. T e coarser particles possess the necessary mass in order to roduce in this case the necessary forcible impact. With a proper selection of the proportions of the ingredients of fine and coarse particles there are so many fine particles contained between two impinging -coarse' articles that the fine particles are pounde rubbed up or ground between them, while the coarser articles are submitted to V only a rather slig t or no appreciable wear at all. It 'is possible by acting in this manner, to convert the fine material in a very short time into large quantities of colloid.

The process becomes particularly eflicient -by simultaneously treating only fine and ab coarse pigticles, the medium sized anules being-e mated as much as possib e, inasmuch as these articles possess only in a very imperfect agree the qualities referred to of the coarse particles, and because, on the other hand, these medium sized granules interfere with the systematic comminution of the small particles,- and produce a rapid wear of the coarse particles. In the practical execution of the process, the fine particles of the material to be comminuted are treated according to the rocess in certain pro ortions together wit small balls of stee or the like. With a proper adjustment of the pro ortions of the fine particles and of the stee balls, the latter do not im inge directly upon each other, there being a ways a sufiiciency of fine particles between them when the impact is to take place, and therefore, no aplpgreciableor noticeable wear of 80 the steel ba takes place, but only the fineparticles are rubbed up. By this operation, large quantities of metals may be converted into colloids up to 70 or 80'percent in from four to five hours. The process may, for instance, be a plied to particles of mass of a size of one undredth of a millimeter or less, while the coarser articles, in the resent' instance the steel alls, possess a iameter of, say one millimeter. 90 Where the greatest degree of purity of the mass is of importance it is advisable to use coarser granules of the mass to be disintegrated itself as a treating medium for the finest owder, instead of usin steel balls or other oreign bodies. Accor ing to the experiments made, it has been found to be of advantage to emplo a large amount of coarse particles or o vsteel balls or the like. However, the proportion of these coarser ingredients, provided they should not be reatly attacke should not exceed one ha f the amount of the fine powder. Y

The process may also be carried out in such a manner that instead of addin coarser particles, the fine powder is mixe with binding agents in suitable proportions,

the said binding agents causing the formation of lumps of some size, and the said lumps being then caused to act upon each other as coarse ingredients, and effecting the destruction and crushing of the fine particles of wder. n the accompanying drawing an embodiment of the apparatus for carrying out my new process is diagrammatically shown; Fig. 1 being a vertical section throu h the apparatus, and Fig. 2 a view of eta1ls turned about 90.

In a casin 1 two shafts 2 and 3 are rotatably journalled,.which-shafts carry the air prolpellers 4 and 5. In front of these air prors there are provided transverse memrs 6 and 7, as more clearly shownin Fig. 2. The material to be treated, as well as the coarser particles, steel balls, etc., are introduced into the casing 1,,through an opening 8, which can be closed. Thereupon, the propellers 4 and 5, b means of the pulleys 9 and 10 mounted on t e propeller shafts are rapidly rotated in opposite directions. .By these rotations, air currents are produced which, as indicated b the arrows 11 and 12 impinge u 11 each. ot er in the center of casing 1. T rough the said transverse members 6 and 7, also lateral displacements are imparted to the said air currents, so that the particles of the material to betreated, suspended in the air currents, not only impinge upon each other, but also frictionally engage each other, resulting in an abrading efi'ect. The air propellers 4 and 5 draw away the air from'the ateral portions of easing 1, forcing the air toward the center of the casing, with the result that at this place, a continuous violent impact of air currents is roduced. The air currents thereby are divided, and passin around the two propellers in the direction 0 the arrows, as shown in Fig. 1, are again caught by the propellers, and then are again roJected toward the center of the caslng. fietween the propellers, there will thus be formed as indlcated by the arrows, continuously circulating whirlin air currents, in which the -part1cles of t e material to be treated are compelled to participate.

In order that these circulating whirling air currents may be produced in a suflicient amount, it is advisable to provide in casing 1, behind'the air propellers, sufliciently large cavities of a suitable shape, thereby facilitating the formation of the said air currents. The air propellers 4 and 5 are made of such a pitch, that the thrust of the air currents near the center (at-the casing is of substantially equal force as the thrust occurring at the outer ends of the wings of the propel ers As the steel balls and coarse particles introduced into the casing, together with the material to be treated participate in the continuous circulating of the whirling air currents produced in the casing, they consequently meet in continuous violent compacts, whereby the material between the said steel balls and the said coarser particles is comminuted to an extraordinary degree of fineness.

The discharge of the comminuted material from the casing is conveniently effected in this way, that a current of gas or air is introduced into the casing through the conduits 17 and 18, while the closing slide 20 is opened, so that the powder is blown out of the casin and is caught above the same. This discharging current must however, be so determined as to its strength, that the formation of the whirling air currents within the casing is not interfered with.

I claim as my invention:

1. The process of producing very fine powders of colloidal fineness, which consists in producing high-speed mutually impinging whirling gas or air currents within a closed casing, causin said currents to circulate within said casing at the rate of several thousand times or more per minute, thereby causing the particles of the material to be treated suspended in said currents to continually impinge upon each other, and at the same time addm to the articles'of the material to be treate a certam amount ofcoarser particles of the same or other material, to thereby increase the mutual impact of the particles of the material to be treated.

2. The process as specified in claim 1, in which the said coarser particles constitute to about one-third of the amount of the material to be treated.

'3. The process as specified in claim 1, in which the said'coarser particles consist of fine steel balls.

4. In an apparatus for producing very fine powders of colloidal fineness, the combination with an entirely enclosed casing, of air propellers rotatably mounted within said casing and spaced so as to provide open spaces at the side and back of said propellers,

. comprisin also lateral members provided in front of the said propellers for imparting to the whirling air currents a lateral movement.

In testimony whereof I aflix m signature.

EMIL' P DSZUS.

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