US1941147A - Classifying apparatus - Google Patents

Description

Dec. 26, 1933. HANS-JOACHIM JOHLIGE 1,941,147

CLASS IFYING APPARATUS Filed June 14, 1932 2 Sheets-Sheet 1 m v- TOR Hans-Joach/m lob/ige A TT ORNE Y 1933. HANS-JOACHIM JCQHLIGE 1,941,147

CLASSIFYIflG APPARATUS Filed June 14. 1932 2 Sheets-Sheet 2 Fig. 3 57 HOG mvn l'foR Hans-Joachim Johlige Patented Dec. 26, 1933 UNITED STATES CLASSIFYIN G APPARATUS Hans-Joachim ,Johlige, Bohlen, near Leipzig, Germany, assignor to the firm Fried. Krupp Grusonwerk Aktiengesellschaft,

Buckau, Germany Magdeburg- Application June 14, 1932, Serial No. 617,121, and in Germany June 19, 1931 8 Claims. (Cl. 209-104) My invention relates to apparatus for classifying solid materials in bulk and more especially crude materials consisting of coarse pieces and lumps of indefinite shape and greatly varying size, such as or'es, coal, coke, lignite, stones, saline raw products, and like minerals, the object being to segregate the material into classes or grades according to the size of the lumps,

The invention relates more particularly to mechanically operated classifying apparatus of the type comprising a plurality of spaced rotary shafts on each of which a great number of spaced disks is mounted which-taken as a wholeform a bed on which a layer of the material to be classified is agitated and gradually advanced as the shafts rotate, so that the smaller and medium sized lumps will drop through the said bed of disks, while the larger lumps are carried forward until they finally drop from the extreme end of the apparatus.

In working with classifying apparatus of this type as widely used in various industries, I have found that the results of their classifying work are often unsatisfactory for the reason that the gaps between the disks of two adjacent shafts periodically vary in their effective width. In consequence thereof a considerable number of pieces of the material which are oversize in respect to the specific size of the pieces of a certain 30 class will prematurely drop through the screen and will be found in a class containing relatively smaller lumps.

For instance pieces of the size of walnuts will be found in the class which should contain only pieces of the size of cherries; or lumps of the size of oranges will be found to have intruded into the class which should contain only lumps of the size of eggs.

Inversely in many cases it happens that a 40 noticeable number of undersize pieces and even large proportions of pulverulent material are found in classes of the material which should contain only larger lumps. My observations have shown that this latterdrawback generally arises from specific working conditions inherent to classifying apparatus of the type concerned, which are unsatisfactory in two respects: Firstly because the layer of the material to be classified, on passing ahead over the bed of disks, is not sufliciently moved about, and raked up throughout its whole depth from top to bottom so as to allow all the smaller pieces to timely slide down from and between the larger pieces and to timely drop through the screen beginning at the early stages of the screening action-but are retained for excessive periods of time, viz, until they reach those sections of the screen provided for the larger lumps; and secondly because the material in the course of the whole classifying treatment is incidentally comminuted and is unduly reduced in size and value, with the result that small pieces are to be found in all classes of the classified material. For instance in classifying soft, brittle and sticky material such as freshly mined brown coal or lignite, dumped from the miners cars onto the classifying ,screen, many small granules and even pulverulent material will be found in classes which should contain only the largest lumps to be directly burnt in furnaces, whereas the smaller grades of the fuel which are to be briquetted contain many oversize lumps. The presence of small granules and of pulverulent material in the fuel of the larger grades which are to be directly burnt is very objectionable because of the tendency of the smaller pieces and pulverulent material to choke the air gaps of the grate of the furnace and because of the heavy loss of substance and weight occurring in the course of transportation from the screening plant to the furnace.

I have also found that the output of screening plants of the type concerned is often considerably impaired through clogging of the screens especially in cases when soft materials of a sticky nature such as brown coal or lignitewhich in their crude condition often contain over 50 percent of waterare to be classified, the lumps of which tending to become pinched and retained between two adjacent disks of the screen.

According to my observations this drawback is due either to the entire absence of appropriate members for stripping off the material pinched between the disks, onto the fact that those stripping members have been occasionally overstrained and accidentally torn, broken or damaged otherwise.

My invention aims at providing an improved classifying apparatus of the type and for the purpose set forth which is of relatively simple design and in which the above indicated drawbacks are eliminated.

One of the principal objects of the invention so to thus design the classifying apparatus that its agitating, raking and screening action upon the material is truly and fully efficient, so as to cause all the smaller pieces to drop through the bed of disks already at the early stages of the classifying work, and so as to obtain a larger output per hour when compared with apparatus I of the same size used heretofore.

In connection therewith the invention aims at providing an improved classifying apparatus by which a better classified material, viz, of truly uniform sizes is obtained, of which the individual classes are substantially free from oversize and undersize pieces.

Another object of the invention is to efficiently yet relatively gently handle the material-consistent with its physical properties, hardness, average size of the lumps, etc.during its passage over and through the classifying apparatus, so that no noticeable comminution of the material will occur even with rather soft and fragile materials such as brown coal, lignite and the like.

Other object of the invention will become incidentally apparent hereinafter.

The nature and scope of the invention are briefly outlined in the appended claims and will be more fully understood from the following specification taken together with the accompanying drawings in which Fig. 1 is a fragmentary side elevation of the 1 feed end of a classifying apparatus according to this invention diagrammatically shown by way of an example,

Fig. 2 is a plan,

Fig. 3 is another plan made in a reduced scale and showing the whole classifying apparatus,

having sections for small, medium, and large pieces,

Fig. 4 diagrammatically shows the arrangement of intermediary circular disks concentrically arranged according to this invention between two adjacent groups of disks,

Fig. 4a is only of explanatory nature, indicating by hatched lines the larger two-cornered gaps which would temporarily exist between four adjacent groups of disks, if there were no intermediary disks provided as in the case of Fig. 4.

Figs. 5 and 6 diagrammatically show structurally modified disks to be used in connection with classifying apparatus according to this in-.

vention.

As far as my research work has revealed amongst classifying apparatus of the type under consideration there are known two species-one in which the disks of two adjacent rotary shafts are arranged in staggered position to each other and are so shaped. that the disks of one shaft will project into the spaces between the disks of the adjacent shafts-the object being to prevent clogging of the open spaces between adjacent disks-and another species in which the rotary shafts are spaced so wide apart from each other that the disks of two adjacent shafts cooperate only with their circumferential edges.

In my opinion the unsatisfactory working of classifying apparatus used heretofore and referred to above is mainly due to the fact that the material under treatment during its agitation is simply pushed ahead by the rotating disks in the general working direction i. e. along the longitudinal axis of the apparatus, but is not effectively rolled around and trundled about in lateral direction across the bed of disks.

In contradistinction to known classifying apparatus the disks of which are arranged in the manner indicated, I propose to structurally aggregate into groups the disks, which are assembled on the rotary shafts, and to angularly displace for cooperation said groups of disks relatively to each other, so as to provide a number of steps over which the pieces of the material will roll aside and trundle about across the bed of disks; my experiments have shown that by appropriateto each other the screening effect of the apparatus is greatly enhanced: A largeroutput per unit of time is obtained, and no undersize pieces will unduly remain on the bed of disks so as to intrude into classes containing larger pieces.

In the embodiment of my invention shown by Way of examples in Figs. 1-4 disks of circular shape, collectively designated 10 in Fig. 1, are provided which are eccentrically mounted on the rotary shafts designated 50-61, and are structurally aggregated into groups of 5, 4, and 3 disks respectively. The material is fed through a hopper 40 and proceeds over the bed of disks in the direction of the arrow 3:.

The aggregation of said disks into groups is conspicuous by the angular displacement of the latter relatively to each other: In Fig. do it is indicated how the groups of circular disks 10a, 1011 may be conveniently displaced relatively to each other by an angle of 180, while the groups of disks 10a, 10a, 10a" and 10b, 10b, 10b" of adjacent shafts 59, 60, 61 extend in the same direction in space i. e. the groups of disks of adjacent shafts forming virtual angles of 0 relatively to each other.

Another important feature of my invention is the provision of auxiliary disks 12 between the groups of disks of the individual shafts: As seen in Figv 4a between every 4 adjacent groups of disks low-10b and 10a'-10b, there would be formed temporarily-twice during each rotation of the shafts-gaps having two pointed corners i, i, indicated in hatched lines, through which correspondingly large pieces of the material would pass and drop down, thus unduly proceeding into a class of the material the diameter of the pieces of which should not exceed the normal width a--b-c respectively between every two adjacent groups of disks, as indicated in Figs. 3 and 4. In order to overcome the said drawback said auxiliary disks 12 of circular shape are inserted between every two adjacent groups of disks 10a, 10b of each shaft and are concentrically fixed on the latter; by this expedient the objectionable projecting corners i, i are eliminated and a uniform width of the gaps is insured.

A subsidiary feature of my invention is the provision of stripping bars 20 of improved design which are arranged between the disks and are designed to safeguard the apparatus against becoming choked, especially in cases when materials of a sticky nature and in moist condition such as brown coal, lignite or the like are to be classified; said stripping bars fit around the rotary shafts and into the spaces between every two adjacent disks and are secured tothe rotary shafts 5061 by resilient hooks 21 surrounding the shafts at an arc exceeding 180, so that they are safe against becoming accidentally detached. In addition thereto the stripping bars 20 are fixed in their operative position by rods 22, extending across the classifying apparatus underneath the bed of disks, and are preferably provided with resilient arms 23 downwardly extending from the hooks 22, so as yieldingly do their scraping sifying apparatus safer against becoming inadbars downwardly extending into the spaces between, the rotary disks at the feed end of the classifying apparatus, shown in Figs. 1 and 2. By said guide bars larger lumps of the material descending through the hopper are prevented from dropping over the rear end of the apparatus; the said guide bars will incidentally act as stripping blades for the disks of shaft 50, so that in this case separate stripping bars can be dispensed with. s

Various changes and modifications may be made in the structural details of classifying apparatus of improved design as described above and in the shape and cooperation of their component parts, without substantially departing from the spirit and the leading ideas of my invention and without sacrificing any advantages obtained thereby. I

Instead of bevel gears 70, shown in Figs. 2 and 3, gears of other types may be conveniently used for rotating the shafts 50-61 in the same direction of rotation.

While circular disks 10 are a convenient shape,

easily and inexpensively to be manufactured,

disks of different design may be used instead andas seen in Figs. 5 and 6with the same result viz, that the'gaps d and e between the cooperating groups of disks of two adjacent shafts will remain substantially constant all through the rotary movements of the disks.

In Fig. 5 disks 15 of elliptical shape are shown, which will fulfill the requirements under consideration, if the cooperating groups of disks of two adjacent shafts 50', 51', 52', 53' are angularly displaced relatively to each other by angles of 90; the angle of displacement'of the groups of disks 15 mounted on the individual shafts being also 90. 7

Another structural modification of the disks is seen in Fig. 6; said disks 16 are of the shape of equilateral triangles having outwardly bulging curved sides. The groups of said disks 16 of two adjacent shafts 50", 51", 52", 53" are angularly displaced relatively to each other by angles of 0 while the angular displacement of the groups of disks 16 of individual shafts is equal to 60.

I am aware that classifying apparatus are known in the art in which rotary cylinders of elliptical cross sectional form, extending across the whole width of the bed of classifying apparatus are used, and in which the respective adjacent cylinders are angularly displaced to each other for cooperation by an angle of 90, so that the gaps between those cooperating cylinders will remain substantially uniform throughout their rotating movements; and I make no claim to elliptically shaped cylinders per se except to their specific design in the form of disks of relatively short length and their specific step-forming arrangement in groups set forth hereinbefore.

I am also aware that disks of the shape of equilateral triangles-but having straight sideshave become ,known in connection with classifying apparatus of the type to which my invention relates; and I make no claim whatever to such triangular disks.

What I claim is:

1. Classifying apparatus for the purpose set forth comprising in combination sets of spaced rotary shafts, the latter being arranged substantialls parallel to each other, means for rotating said "shafts in the same direction of rotation, spaced disks mounted on said shafts so as to form a bed of disks and to be revolved with the shafts, the disks of individual shafts being structurally aggregated into groups of which alternate groups are angularly'displaced relatively to the intermediate groups of disks, so as to form steps, causing the material under treatment to crosswisely roll over the bed of disks as the-disks rotate, the disks of adjacent shaftsof individual sets of shafts being cooperatively arranged substantially in line with each other so as to present gaps between their opposed circumferential edges, the form of said disks and the angular position of the groups of disks of two adjacent shafts relatively to each other being so chosen, that the gaps under consideration will remain substantially uniform in width throughout the rotary motion of the shafts.

2.. Classifying apparatus for the purpose set forth and having the features outlined in claim 1, in which circular disks are provided, eccentrically arranged on the said rotary shafts, the stepsforming groups of disks of the individual shafts being angularly displaced relatively to each other by an angle of 180, while the cooperating groups of disks of adjacent shafts are angularly displaced relatively to each other by an angle of 0.

3. Classifying apparatus having the features outlined in claim 1, in which elliptical disks are provided mounted on the rotary shafts in such position that the virtual centres of symmetry of the disks coincide with the centres of the respective shafts, the steps-forming groups of disks of the individual shafts being angularly displaced relatively to each other by an angle of 90, while the cooperating groups of disks of adjacent shafts .are angularly displaced relatively to each other by angle of 90.

4. Classifying apparatus having the features outlined in claim 1, in which disks of the shape of equilateral triangles are provided, having outwardly projecting curved edges and being so mounted on the rotary shafts that their virtual centres of symmetry coincide with the centres of the respective shafts, the groups of disks of the individual shafts being angularly displaced relatively to each other by an angle of 60, while the cooperating groups of disks of adjacent shafts are displaced relatively to each other by an angle of 0.

5. Classifying apparatus for the purpose set forth and having the features outlined in claim 1, in which circular disks are provided, eccentrically arranged on the said rotary shafts, the groups of disks of the individual shafts being angularly displaced relatively to each other by an angle of 180, while the cooperating groups of disks of adjacent shafts are angularly displaced relatively to each other by an angle of 0, auxiliary circular disks being mounted between adjacent groups of disks of individual shafts concentrically to the latter.

forth and having the features outlined in claim 1, in which stripping bars are provided, downwardly extending into the spaces between the disks of the extreme row of disks at the feed end of the apparatus and snugly fitting over the respective rotary shaft.

HANS-JOACHIM JOHLIGE.

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