CLASSIFYING WHEEL FOR A CENTRIFUGAL-FORCE AIR CLASSIFIER

Abstract

A classifying wheel for a centrifugal-force air classifier where the flow pattern of the classifying air is contrary to its centrifugal direction, namely centripetal, and which is equipped with extensions fitted to the classifying wheel vanes within the flow channels which influence the flow pattern is to be executed in wear-protected design. This is achieved in that the classifying wheel has at least one reinforcing ring which has uniformly spaced hooks arranged around its periphery which fix the classifying wheel vanes to the extensions so that the outside radial edge of the classifying wheel vanes is not in contact with the reinforcing ring.

Claims

1. Classifying wheel for a centrifugal-force air classifier where the flow pattern of the classifying air is contrary to its centrifugal direction, namely centripetal, and which is equipped with classifying wheel vanes arranged in a ring, which are located between an annular hub plate which supports the classifying wheel hub and an annular cover plate, whereby flow channels are formed between the classifying wheel vanes by the faces of the classifying wheel vanes tilted at an angle to the rotational axis and spaced at a distance to each other as well as the extensions fitted to the classifying wheel vanes within the flow channels which influence the flow pattern, wherein at least one reinforcing ring is located between the hub plate and the cover plate which has hooks uniformly spaced around the periphery which connect the classifying wheel vanes with the extensions so that the radial outside edge of the classifying wheel vanes is free of the reinforcing ring.

2. Classifying wheel in accordance with claim 1, wherein the hooks of the reinforcing ring engage positively with the extensions.

3. Classifying wheel in accordance with claim 1, wherein the classifying wheel vanes comprise inside classifying wheel vanes and outside classifying wheel vanes which have an extension.

4. Classifying wheel in accordance with claim 3, wherein the radial outside classifying wheel vanes have extensions in the radial inside zone of the width of the classifying wheel vanes which extend over the height of the classifying wheel vane.

5. Classifying wheel in accordance with claim 3, wherein the inside classifying wheel vanes and the outside classifying wheel vanes are at a different angle to the radial direction of the classifying wheel.

6. Classifying wheel in accordance with claim 3, wherein the outside classifying wheel vanes are completely or partially protected against wear.

7. Classifying wheel in accordance with claim 3, wherein the outside classifying wheel vanes are equipped with wear-protection plates which are fitted in rotational direction to the front side of the classifying wheel vanes which extend over the height and width of the vane to the extension, whereby the extension itself is not in contact with the wear-protection plates.

8. Classifying wheel in accordance with claim 7, wherein the wear-protection plate of the outside classifying wheel vanes also covers the radial outside edge.

9. Classifying wheel in accordance with claim 3, wherein the outside classifying wheel vanes in plug-in design are inserted into guideways between the hub plate of the classifying wheel subassembly, the cover plate and the hooks of the reinforcing ring.

10. Classifying wheel in accordance with claim 3, wherein the wear protection of the outside classifying wheel vanes consists of ceramic, plastic, hard material or tungsten carbide.

11. Classifying wheel in accordance with claim 3, wherein the wear protection of the outside classifying wheel vanes is accomplished by means of surface hardening, thermal spray process or by build-up welding.

12. Classifying wheel in accordance with claim 3, wherein the extensions of the classifying wheel vanes fulfil the following functions: flow control in the flow channels reinforcing the classifying wheel vanes serve as a contact point for the hooks of the reinforcing ring to hold the classifying wheel vanes.

13. Classifying wheel in accordance with claim 3, wherein the reinforcing ring absorbs the centrifugal forces generated by rotation of the classifying wheel by way of the hooks and the extensions of the outside classifying wheel vanes.

14. Classifying wheel in accordance with claim 1, wherein the diameter of the reinforcing ring is smaller than the diameter of the hub plate and cover plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other details, features and advantages of the subject matter of the invention arise from the subclaims and from the following description of the associated drawings in which a preferred design of the invention is shown by way of example. The drawings show:

[0035] FIG. 1 A cross-sectional view of an invention-design classifying wheel

[0036] FIG. 2 A section of the reinforcing ring

[0037] FIGS. 3a, 3b, and 3c Profiles of the outside classifying wheel vane

DETAILED DESCRIPTION

[0038] FIG. 1 shows the invention-design classifying wheel 1 for an air classifier. It comprises the classifying wheel subassembly, outside classifying wheel vanes 2 and an annular cover plate 3. The classifying wheel subassembly consists of the annular hub plate 4, the classifying wheel hub 5, the inside classifying wheel vanes 6 and the annular end plate 7 of the classifying wheel subassembly. These parts are permanently connected to each other.

[0039] The inside classifying wheel vanes 6 are spaced evenly and radially around the classifying wheel hub 5 and are held in slots in the hub plate 4. On the side opposite the hub plate 4, the inside classifying wheel vanes 6 are fixed in place by means of an end plate 7. The inside classifying wheel vanes 6 are trapezoidal in shape. The outside classifying wheel vanes 2 are arranged adjacent to the inside classifying wheel vanes 6 in radial outside direction. Their number is identical to that of the inside classifying wheel vanes 6 and they are also spaced evenly. They are inclined in radial direction so that the inside and outside classifying wheel vanes display a different angle to the radial direction of the classifying wheel. The outside classifying wheel vanes 2 are inserted and held in slots or guideways in the hub plate 4 and the cover plate 3. The cover plate 3 is screwed to the basic subassembly.

[0040] In the invention-design example, the classifying wheel 1 has two reinforcing rings 8. They are both arranged equidistant from the cover plate 3 and the hub plate 4 and at a distance from each other. In another invention design not shown here, the distance between the cover plate 3, the hub plate 4 and the two reinforcing rings 8 is identical.

[0041] The reinforcing rings 8 are mounted in recesses on the inside classifying wheel vanes 6.

[0042] FIG. 2 shows a section of the reinforcing ring 8 of the classifying wheel. The reinforcing ring 8 has hooks 9 distributed and evenly around its periphery radially to the outside. The number of hooks 9 matches the number of classifying wheel vanes. The outside classifying wheel vanes 2 have extensions 10. These extensions 10 are arranged in the radial inside zone of the classifying wheel vanes over the height of the vanes. The hooks 9 of the reinforcing ring and the extensions 10 of the outside classifying wheel vanes 2 engage positively with each other, in this way the outside classifying wheel vanes 2 are held by the hooks 9 of the reinforcing ring 8. The diameter of the reinforcing ring 8 is smaller than the diameter of the cover plate 3 and hub plate 4. The diameter described by the hooks 9 is smaller than the diameter described by the radial outside edges of the classifying wheel vanes 2. This means that the reinforcing ring 8 is outside the dominant impact stress zone and is thus subject to minimal wear.

[0043] FIG. 3a shows a cross-section through an outside classifying wheel vane 2. The classifying wheel vane 2 has an almost rectangular profile and exhibits an extension 10 at one end. In installed condition, this extension of the classifying wheel vane is located at the radial inside zone of the vane. Polygon-shaped in profile, this extension 10 extends over the entire height of the classifying wheel vane 2. These classifying wheel vanes 2 are made completely of one single material such as a wear-proof material (ceramic or tungsten carbide). Because the outside classifying wheel vanes 2 are inclined at an angle, the radial inside edge of the classifying wheel vane 2 has an angle to permit abutting the inside classifying wheel vane 6 with a positive fit.

[0044] FIG. 3b shows an outside classifying wheel vane 2 in profile which has the same shape as the outside classifying wheel vane 2 from FIG. 3a, but is not made completely of one single wear-proof material. The classifying wheel vane comprises the classifying wheel vane base and the wear protection. The wear protection is realised here by means of a wear plate 11 made of wear-proof material. The wear plate 11 extends over the entire height of the outside classifying wheel vane from the edge to the extension 10. The area of the actual extension 10 has no wear plate so that the hooks 9 of the reinforcing ring 8 can engage in the extension 10 in a positive manner. Alternatively, the top and bottom area of the classifying wheel vane that are accommodated in the slots of the cover plate and hub plate can be without a wear-protection plate. The wear-protection plate is bonded to the classifying wheel vane. In a different invention design, the wear plate is soldered or welded on. The wear protection can also consist of several small plates arranged next to each other.

[0045] FIG. 3c shows another design of the wear protection for the outside classifying wheel vanes 2. In addition to the wear plate 11, a wear-proof material is applied also to the radial outside edge of the outside classifying wheel vane.

REFERENCE NUMBER LISTING

[0046] Classifying wheel 1

[0047] Outside classifying wheel vanes 2

[0048] Cover plate 3

[0049] Hub plate 4

[0050] Classifying wheel hub 5

[0051] Inside classifying wheel vanes 6

[0052] End plate 7

[0053] Reinforcing ring 8

[0054] Hook 9

[0055] Extension 10

[0056] Wear plate 11

[0057] Classifying wheel vane base 12