EP0244744A2 - Centrifugal sifter - Google Patents

Abstract

A centrifugal classifier for classifying air, feed solids, fines and coarse particles has a housing with inlets and outlets. The housing is substantially parallelepipedic and contains a plurality of classifier rotors. Each rotor is connected to a separate outlet or to two separate outlets for classifying air and fines.

Description

The invention relates to a centrifugal classifier according to the preamble of patent claim 1.

In the conventional classifiers, only one classifying wheel equipped with the classifying vanes is provided in the housing (eg DE-OS 16 07 631). The throughput of these classifiers is limited. In order to increase the performance, a classifying rotor with several longer blades has already been arranged in a classifier housing, which has an outlet for fine material / classifying air mixture on both ends, which practically connects two or more classifiers. The visible blades can extend between two end rings mounted in the end walls of the housing (DB-PS 28 25 400) or by means of Support disks must be mounted on a continuous shaft (DB-PS 29 51 819). With this one achieves a throughput that is several times greater with greater selectivity. However, up to now a certain classifier has only ever delivered a certain separating grain size at a certain speed and a certain air throughput.

In contrast, the invention has for its object to provide a classifier with even higher performance, from which several grain fractions with different separating grain sizes can be withdrawn at the same time, the individual fine grain fractions should have as little oversize and as little undersize as possible. The solution to this problem is specified in the characterizing part of claim 1. According to the invention, therefore, a plurality of classifying rotors are provided in a cuboid housing, from each of which a specific fine-grain fraction can be extracted.

The rear view rotor in the flow direction preferably has a larger separating grain size than the front one.

Further configurations are specified in the subclaims.

In order to explain the invention in more detail, from examples of management described with reference to the drawing.

• Fig. 1 und 2 ein erstes Ausführungsbeispiel in zwei zueinander rechtwinkligen vertikalen Schnitten;
• Fig. 3 und 4 ein zweites Ausführungsbeispiel;
• Fig. 5 und 6 ein drittes Ausführungsbeispiel.
• Fig. 7 zeigt in einem vertikalen Querschnitt ein viertes Ausführungsbeispiel;
• Fig. 8 zeigt ein fünftes Ausführungsbeipsiel.

Show it:

• 1 and 2 a first embodiment in two mutually perpendicular vertical sections;
• 3 and 4 a second embodiment;
• 5 and 6 a third embodiment.
• Fig. 7 shows a fourth embodiment in a vertical cross section;
• 8 shows a fifth exemplary embodiment.

1 and 2, three known rotors 2, 3, 4 are arranged one above the other in an elongated, box-shaped housing 1. The rotors are mounted on one housing wall 5 and driven by a separate drive 6, 7, 8. On the other side, a tube penetrating the side wall 9 of the housing projects into the inside space of the rotor 2, 3, 4, so that each rotor is connected to a separate fine air outlet 10, 11, 12. The gap between a ring 13 connecting the rotor lamella at its free end and the wall 9 can be sealed by a labyrinth seal - with or without flushing medium. A conical or funnel-shaped classifying air classifying material inlet 14 is provided at the bottom.

The view rotors 2, 3, 4 can have different separation limits. For this purpose, they can be driven at different speeds, operated with different suction, or they have different separation limits from the start (i.e. even with the same speed and suction). The lower (or in the flow direction first) classifying rotor 2 preferably has the smallest separating limit, the middle classifying rotor 3 has a middle classifying limit and the upper (or in the flow direction third) classifying rotor 4 has the largest classifying limit.

Thus, the finest fine material is extracted from the lowermost / first outlet 10, a medium fine material from the middle outlet 11 and a somewhat coarser fine material is extracted from the upper outlet 12 together with classifying air. A nozzle 15 is attached at the top, from which a remaining part of the classifying air together with still in this contained, relatively coarse material is extracted.

The air flows are indicated by wide arrows, the particle flows by narrow arrows.

By means of the lowermost classifying rotor 2, the finest particle fraction is first extracted from the classifying material introduced below. This finest grain fraction is therefore no longer present above the lowest rotor 2. `The same applies to the middle and also to the upper view rotor 3,4. So you get several grain fractions with very "steep" grain distribution, i.e. with very little oversize and very little undersize.

3 and 4 corresponds essentially to that of FIGS. 1 and 2 (same parts are denoted by the same reference numerals), but with the difference that the particle mixture to be divided into several grain fractions by means of an inlet 16 arranged at the top / side in the Sifter housing 1 is entered, while a funnel-shaped coarse material outlet 17 is provided at the bottom, into which a classifying air inlet 18 opens laterally.

This version is intended for coarser visual goods, at which the coarse material is too large or heavy to be discharged with a stream of air.

Apart from the effect that the material to be classified is divided into more than two grain fractions, there is a better classifying efficiency. The classifying rotors, which are provided at a relatively short distance from one another, influence one another. In particular, adhering particles are separated (deagglomerated).

The view rotors can rotate in the same direction or in opposite directions.

Throughput is also increased.

If necessary, the view rotors can also be operated at the same speed, i.e. of the same separation size, let it run if it is only the larger throughput that matters, i.e. large quantities of visible material are to be divided into only two grain fractions.

5 and 6 is particularly geared towards great performance. For this purpose, view rotors 19, 20 which are suctioned off on both sides and are several times longer and have a correspondingly higher performance. The classifying blades extend between rings 21 which are mounted on both sides in the housing 22. In each ring 21 projects a piece of pipe 25 which is connected to a separate outlet channel 26 on the outside, which in this case extends upwards. One face ring 21 is driven, in FIG. 5 by V-belts.

It is also possible to provide more than two classifying rotors 19, 20 suctioned off on both sides, e.g. three rotors arranged horizontally next to each other or in a triangle or four rotors in a square.

Arranged underneath the rotors and symmetrically to them is a funnel-shaped guiding device 23 for a mixture of visible material and air, so that both classifying rotors 19, 20 are acted upon uniformly over their entire length. The coarse material is drawn off through a funnel-shaped lower housing attachment 24.

It should be mentioned that even in the embodiments according to FIGS. 1-4, instead of the one-sided suction rotors, suction rotors can be used if a correspondingly high output is important.

In the embodiment according to FIG. 7, three rows, each with four classifying rotors 30a, b, c, are provided one above the other. The rotors 30a of the bottom row have the smallest, the rotors 30b of the middle row have a middle and the rotors 30c of the top row have a coarser separation size. Seen from the side, this arrangement corresponds to that according to FIG. 1. As in FIG. 1, several fine material fractions are obtained, but each in four times the amount. ^-

The visible-air mixture is introduced into the housing 22 at the bottom by means of pipes. Coarse material is discharged through a funnel-shaped lower housing part 24.

In the embodiment according to FIG. 8, at the bottom three rotors 30a are provided next to one another and above / between these two rotors 30b and finally / above and between them a single rotor 30c. Fine fines are withdrawn from the bottom rotors 30a, medium fines from the middle rotors 30b and coarser from the top rotor 30c. This arrangement takes account of the fact that upwards (or in the direction of flow) there is less and less visible material mixture, that is to say upwards a lower classifier throughput is sufficient. The mutual influence of the rotors is special in this version large.

To further increase this effect and make even better use of space, separating rotors with a larger diameter can be arranged between those with a smaller diameter.

Reference symbol list

• 1 housing
• 2,3,4 classifying rotors
• 5 housing wall
• 6,7,8 drives
• 9 (other) side wall
• 10,11,12 pipes (outlets)
• 13 rings
• 14 Visual air visual goods inlet
• 15 sockets
• 16 visible material inlet (Fig. 3,4)
• 17 coarse material outlet
• 18 Clear air inlet
• 19.20 view rotors, on both sides, Fig. 5,6
• 21 rings
• 22 housing
• 23 guidance device
• 24 lower housing attachment
• 25 pieces of pipe
• 26 separate fine material clean air outlet channels
• 30a, b, c view rotors in Fig. 7,8

Claims (4)

1. centrifugal classifier with a housing provided with inlets and outlets for classifying air, classifying material, fine material and coarse material,
characterized,
that in a substantially cuboid housing (1; 22) a plurality of classifying rotors (2, 3, 4, 19, 20) are arranged, each on a separate fine air outlet (10, 11, 12) or on two separate fine air outlets (25, 26) are connected. 2. classifier according to claim 1,
characterized,
that the view rotors are arranged parallel to each other. 3. classifier according to claim 2,
characterized,
that two or more rows of side-by-side view rotors are provided one above the other (Fig. 7,8). 4. classifier according to claim 3,
characterized,
that the classifying rotors in one row are laterally offset from the classifying rotors in another row (FIG. 8).

Images