WO2002090004A1

WO2002090004A1 - Separator

Info

Publication number: WO2002090004A1
Application number: PCT/EP2002/001866
Authority: WO
Inventors: Rudolf Heidkamp
Original assignee: Loesche Gmbh
Priority date: 2001-05-10
Filing date: 2002-02-21
Publication date: 2002-11-14
Also published as: DE10122644B4; DE10122644A1

Abstract

The invention relates to a separator, for example an air roller-mill separator or an air classifier, comprising a vane ring as the stator (2) and a rotor that is located radially in the interior (4). According to the invention, the stator and/or the rotor (4) are configured in such a way that at least one radially variable classifying chamber (6) comprising narrower and broader classifying chamber regions is formed.

Description

CLASSIFIERS

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

Preferred fields of application of the classifier according to the invention are airflow roller mills, in which the classifier is arranged above the grinding chamber. A regrind-fluid mixture rising in a swirl flow is fed to the classifier from below, separated fine material is drawn off in the fluid stream and coarse material is returned to the grinding chamber via a freeze.

However, the invention is also suitable for air classifiers with a classifying chamber, to which a gas stream is supplied from the outside, in particular tangentially, and ground material is fed in from above, generally via a spreading disc.

Known mill classifiers have at least one outer guide flap, hereinafter also referred to as "stator" for short, and a rotor on the radial inside, which limit a viewing space.

From DE 36 17 746 AI is placed on a roller mill classifier with a lamellar basket as a rotor and a concentrically arranged, fixed outer guide flap known. The visible space between the circular cylindrical rotor and stator is a cylindrical annular space and has a constant circular cross section over the entire height.

A mill classifier is known from EP 0 204 412 B1, the rotating lamella classifier basket of which is surrounded concentrically by an adjustable guide vane system. The guide vane system consists of two or more sets of guide vanes, which are arranged one above the other and can be adjusted independently of one another about vertical axes in order to be able to vary the flow against the rotating lamellar basket. In this known mill classifier, too, the classifying area is designed as a cylindrical annular space.

The rotary air centrifuge classifier described in DE 35 15 026 Cl with an almost central regrind and tangentially positioned viewing air channels, a cylindrical centrifugal basket as a rotor and axially divided guide vane rings as a stator likewise has a visual space designed as a cylindrical annular space.

A longitudinally conical view space is formed in the high-effect blind classifier described in ZKG, 46th year, 1993, number 8, page 444-450, figure 8, which is integrated in a Loesche airflow roller mill. The conical view space is formed by concentrically nested blind cones and conically arranged rotor strips of a double cone rotor. The radial distance between the static diffuser and the rotor strips is largely constant in the axial direction. This also applies to the mill classifier described in DE 44 23 815 C2, in which a double-cone rotor is preceded by two adjustable flap rings arranged axially one above the other. Above the ledge rotor, a deflection device is provided in an area adjacent to the upper guide vane ring, through which the ascending fluid-regrind flow is fed to the deflection and downward flow with the effect of gravity to the conical visible space in longitudinal section.

From DE 197 08 956 AI a sifter is known which is intended to enable a step-like multiple sifting of tangentially supplied material. The classifier housing has an inlet spiral divided into superimposed feed channels for the adjustable supply of classifying air into the classifying room, in which a classifying rotor with classifier basket and rotor strips attached to its periphery is arranged. Guide vanes of the stator are arranged in a stationary manner concentric to the rotor strips and limit the viewing space. The sight basket is divided into several cylindrical sections over its height, and in adaptation to this, the stationary guide vanes in the area of the basket section with the smallest outside diameter have a smaller radial distance from the classifier axis than in the area of the basket section with the largest outside diameter. As a result, a uniformly wide viewing area is formed over the entire viewing basket, and only the radial distance between the classifying axis and the individual ring-cylindrical viewing zones of the basket sections differs.

The area of use of the classifiers is determined, among other things, by the air and solids supply as well as the separation limit to be reached and the required throughput. Around To keep the manufacturing costs as well as the costs for development and construction as low as possible, a sifter construction is to be aimed for, which is suitable for different visible or regrind material and which guarantees the required separation limits and throughput.

The known classifiers have a horizontal flow field with a vertical axis of rotation, which is formed by a flow running in a spiral from larger to smaller radii with the rotor axis in the center of the flow field. The radial expansion of the visible space, length of the rotor strips, flow velocity, particle concentration and also the alignment of the guide vanes and the rotor strips are decisive for the desired visual effect, selectivity and visual performance.

At the same time, it is known that a uniform flow of particles over the height of the visible space, in particular in the case of roller mills, cannot be achieved. This is due in particular to the required deflection of the regrind-fluid mixture. In addition, due to the increased particle concentration occurring between the grinding rollers, a uniform solids distribution over the classifier cannot be achieved.

The invention is based on the task of creating a classifier which, with a relatively simple construction and inexpensive production, is suitable for classifying a wide variety of ground materials and classifiable materials and which ensures the separation limits and throughputs required in each case with a relatively low expenditure of energy. According to the invention the object is achieved by the features of claim 1. Useful and advantageous configurations are contained in the subclaims and in the description of the figures.

A basic idea of the invention is to use the advantages of a narrow and a wide view space as well as the axial extension of the view space and to bring about a synergetic effect by means of a new classifier concept. Another basic idea is to depart from the previously known design principle of an annular visible space with constant extension in the radial and axial directions and to create a classifier with a different visible space in the radial direction and expediently also in the axial direction.

According to the invention, the visible space in the radial direction, based on each cross section, has narrower and wider visible space areas S1, S2 and can additionally also have axially different visible area areas. The narrower and wider viewing area areas are formed in all horizontal planes of the classifier, which extend diametrically to the longitudinal axis of the classifier rotor or classifier.

In a first, preferred embodiment, a circular cylindrical guide vane ring is combined with a rotor, the rotor strips of which form an elliptical cylinder.

The visible space delimited by a circular cylindrical guide vane ring and the elliptically cylindrical rotor is a ring of unequal thickness in cross section and has narrower and wider visible area areas which rotate with the rotor in the manner of a Wankel motor. With the classifier according to the invention, surprisingly good selectivity and visual performance are achieved. It is assumed that the variable viewing area in the radial and / or axial direction achieves the advantages of a narrow viewing area, in particular a uniform dividing limit, and a wider viewing area, in particular a relatively large viewing performance.

In addition, a classifier with a radially and / or axially variable classroom for different materials, e.g. suitable for raw meal, cement, quartz, slag and coal, and also fine separations and high throughput rates can be realized.

A radially variable viewing space can be achieved with different rotor and / or stator designs.

For example, the cross section of the rotor can be designed as a polygon, advantageously as a square, an equilateral triangle, pentagon, octagon, etc. In a first variant, the cross section of the rotor and the cross section of the stator are constant over the entire height, so that the visible space in this first variant only varies in the radial direction, but not in the axial direction.

In principle, a radially variable visible space can also be created by a guide vane ring that is polygonal or elliptical in cross section and a circular cylindrical rotor, and also by a polygonal or elliptical rotor cylinder. In a second embodiment variant, the classifier according to the invention has a variable classroom in the axial direction. In the radial direction, the distance between the rotor strips and the guide vane ring can be constant or can also vary. In its axial extent, at least the rotor, possibly also the stator or also rotor and stator, is provided with at least one change in cross section.

A circular-cylindrical or conical rotor, which has at least one waist or a shape radially outward, can advantageously be arranged in a circular-cylindrical or conical guide vane ring.

The change in cross-section of the rotor over its height can be gradual or continuous, e.g. be concave, convex or beveled in longitudinal section, or be stepped.

A classifier can have a circular cylindrical stator and a rotor, which is designed in longitudinal section as a single-shell hyperboloid. It is assumed that in the case of classifiers with an axially variable classroom, the higher particle concentration that is usually present in the upper classifier area is compensated for by the rotating, axially narrower and wider classroom distances and a more uniform flow of particles across the classroom height is achieved.

In a further development of the invention, a visual space is formed both radially and axially variable. It is useful if the rotor, for example, as an elliptical or polygonal cylinder is formed, with waists and / or formations, which may be continuous and / or step-shaped, is provided on its circumference facing the viewing space, while the stator is circular cylindrical or also conical.

In a further embodiment of the invention, the gas-solids flow in the variable visual space is additionally influenced by guide devices on the rotor and / or stator. Such guide devices can be, for example, helical or helical guide plates and / or horizontal and / or oblique ribs and also contribute to the uniformity of the solids concentration and to transport in the viewing area.

The ribs can be arranged in front of, between and / or behind the guide flaps or guide vanes and can be designed as a helical rib. Instead of or in addition to the guide flaps or guide vanes, a wire mesh can be used for the stator and fastened by means of recesses.

The rotor can have vertical and / or rotor strips or rotor bars. Horizontal or oblique guide plates or ribs can also be arranged as guide devices in front of, between and / or behind the rotor strips. Furthermore, a helical ribbing is possible in order to optimize the flow in the viewing area and within the rotor. The rotor can also be provided with a wire mesh instead of or between the bars, can be designed to be variable over the height and can be provided with corresponding recesses. The guide blades and / or rotor strips can be closed and / or open in cross section. With a closed design, an approximately biconvex or elliptical cross section is advantageous. An open design widens the channels between the guide vanes or rotor strips and can optimize the visual effect depending on the material to be sifted, with a corresponding orientation or a predeterminable swivel angle.

The radial and axial variable visible space according to the invention can thus be realized by an appropriate arrangement and / or configuration of the rotor strips and / or guide vanes of the stator.

The invention is explained below with reference to a drawing. These show in a highly schematic representation

1 to 9 cross sections of classifiers in the area of a stator and rotor and a radially variable classifying room;

10 to 15 are longitudinal sections of classifiers in the area of a stator and rotor and an axially variable classifying room;

16 and 17 are perspective views of a

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The spaced-apart guide flaps (not shown) of the stator 2 entering the gas-solid flow are moved spirally as a function of the flow speed and the rotational speed of the rotor 4 and are influenced by the narrow viewing area S1 and subsequent wider viewing area S2.

The classifier designs shown in FIGS. 5 and 6 have a circular cylindrical, conventional rotor 4 and a stator 2 (FIG. 5) or polygonal stator 2 (FIG. 6) in cross section. In both design variants of FIGS. 5 and 6, the visible space 6 is of different width in cross section and has narrow visible space areas S1 and wider visible area areas S2, which, however, in contrast to the design variants of FIGS. 1 to 4, are constant in location and do not circulate.

7 to 9, the stator 2 is in each case polygonal and the rotor 4 is square in cross section (FIG. 7), elliptical (FIG. 8) and as a simultaneous triangle (FIG. 9). The circumferential narrower visible areas S1 and wider visible areas S2 are clearly recognizable.

Figures 10 to 15 are intended to convey possible classifier constructions with an axially variable classroom 6. Of the stator 2 and rotor 4, only the contours delimiting a viewing space 6 are shown.

Figure 10 shows a preferred construction. A circular-cylindrical stator 2 is arranged concentrically around a rotor 4, which is designed as a single-shell hyperboloid is formed and has a concave waist 8. In the example in FIG. 10, this concave waist 8 is formed in the center. There is also the possibility of moving this waist 8 up or down. The rotor 4 in FIG. 11 is provided with a formation 9 which extends almost over the entire height of the rotor 4. The stator 2 is designed as a circular cylinder.

12 shows a conical stator 2, which concentrically surrounds a rotor 4 with an upper and a lower curved shape 9 and a waist 8. Instead of the conical stator 2, a circular cylindrical stator could also be used.

13 has a stator 2 tapering upwards and then again slightly widening and a slightly conical rotor 4. The rotor 4 could also be provided with at least one shape 9.

14 has a central circular cylindrical region 10 and an upper and lower conical region 11, 12. The stator 2 is circular cylindrical.

The stator 2 in the exemplary embodiment according to FIG. 15 is also of circular cylindrical design. As in FIG. 14, the rotor 4 is provided with different diameter ranges, the transitions 15 of which, however, are not continuous, but rather step-shaped. In this example, the viewing space 6 has a wider viewing space area from the bottom up and narrower viewing area areas S1 upwards.

The rotor 4 according to FIG. 16 is provided on the outer area of the rotor strips (not shown) with a helical or helical gene guide element 13 provided. The guide element 13 is designed here as a sheet which projects radially outwards and is directed upwards and is fastened to a circular-cylindrical rotor 4.

In FIG. 17, diagonally arranged guide elements 13 are attached to vertical viewing strips 24 of the conical rotor 4.

The radially and / or axially variable viewing space 6 can be achieved by appropriately arranged guide vanes and / or viewing strips or by guide vanes and / or viewing strips configured in accordance with the optimal viewing area geometry and basically arranged parallel to the classifier longitudinal axis.

18 shows a circular cylindrical stator 2 with vertical guide blades 22. In order to form an axially variable viewing space 6, the guide vanes 22 widen from bottom to top, whereby they can also be wider in the lower area than in the upper area. The rotor strips of the rotor 4, not shown, can expediently be arranged to form a circular cylinder.

The rotor 4 according to FIG. 19 is circular cylindrical on the inside and elliptical on the outside. For this purpose, the viewing strips 24 have a different width and corresponding arrangement.

Claims

1. Sifter with a viewing space (6), which one

Stator (2) and a rotor (4) is limited, the stator (7) having at least one guide vane ring which is arranged concentrically around the rotor (4), characterized in that the visible space (6) is designed to be variable at least in the radial direction and has narrower visible areas (S1) and wider visible areas (S2) in each cross-section.

2. Sifter according to claim 1, characterized in that the stator (2) is circular cylindrical and the rotor (4) is designed as an elliptical cylinder.

3. Sifter according to claim 1, characterized in that the stator (2) is circular cylindrical and the rotor (4) in cross section as a polygon, for example as a square, an equilateral triangle, a pentagon, hexagon or octagon, and that the cross section of the rotor (4) and the cross section of the stator (2) are constant in the axial direction.

4. Sifter according to claim 1, characterized in that a radially variable viewing space (6) is formed by a circular-cylindrical rotor (4) and a polygonal or elliptical stator (2) in cross section.

5. Sifter according to claim 1, characterized in that the viewing space (6) between a stator (2) and a radially inner rotor (4) is also designed to be variable in the axial direction.

6. Sifter according to claim 5, characterized in that the rotor (4) has cross-sectional changes in the axial direction and the viewing area (6) has narrower viewing area areas (S1) and wider viewing area areas (S2) in the axial direction.

7. Sifter according to claim 5 or 6, characterized in that the cross-sectional changes of the rotor (4) are formed gradually or step-like and have approximately concave, convex or conical contours in longitudinal section.

8. Sifter according to one of claims 5 to 7, characterized in that the viewing space (6) is formed by a circular cylindrical stator (2) and by a rotor (4) which is formed in longitudinal section as a single-shell hyperboloid.

9. Sifter according to one of claims 5 to 7, characterized in that the rotor (4) and / or the stator (2) have at least one waist (8).

10. Sifter according to one of claims 5 to 7, characterized in that the stator (2) and / or the rotor (4) have at least one shape (9).

11. Sifter according to one of claims 9 or 10, characterized in that the stator (2) is conical and the rotor (4) with a waist (8) and / or shape (9) or conical.

12. Sifter according to one of claims 5 to 7, characterized in that the stator (2) is circular-cylindrical and the rotor (4) is formed with a central circular-cylindrical region (10) and an upper and lower conical region (11, 12).

13. Sifter according to one of claims 5 to 7, characterized in that the stator (2) is circular-cylindrical or conical and a viewing area (6) with narrower viewing area areas (S2) and wider viewing area areas (S2) is formed by a rotor (4) which has regions (10, 11, 12) with different diameters in the axial direction, step-shaped transitions (15) being formed between these regions (10, 11, 12).

14. Sifter according to one of the preceding claims, characterized in that the rotor (4) and / or the stator (2) are provided with guide elements (13) which are directed into the viewing space (6).

15. Sifter according to claim 14, characterized in that the guide elements (13) are arranged helically or helically and in the direction of a fine material discharge.

16. Sifter according to claim 14 or 15, characterized in that the rotor (4) is conical and has inclined guide elements (13).

17. Sifter according to one of the preceding claims, characterized in that the radially and / or axially variable viewing space (6) is formed by guide vanes (22) and / or rotor strips (24) which have a different width in the axial direction.

18. Sifter according to one of the preceding claims, characterized in that the stator (2) has guide vanes (22) or guide vanes which are profiled and / or open and / or closed and / or have guide elements (13) which are in the flow direction are arranged in front of, between and / or behind the guide vanes (22) or are designed as helical ribs.

19. Sifter according to one of the preceding claims, characterized in that the rotor (4) has rotor strips (24) which are arranged vertically and / or obliquely and are provided with ribs in front of, between and / or behind the rotor strips (24) are or have a helical ribbing.

20. Sifter according to one of the preceding claims, characterized in that the stator (2) and / or the rotor (4) has a wire mesh and recesses are provided for fastening the wire mesh and / or the guide blades or rotor strips.

21. Sifter according to one of the preceding claims, characterized in that the stator (2) has guide vanes or guide vanes which are open and / or closed in cross section.