Device for generating gas bubbles in suspensions for the enrichment of mineral and non-mineral raw materials and use of such a device

Abstract

The invention relates to a device for generating gas bubbles in suspensions, which are contained in a tank, having a rotation-symmetric stator (16) and a rotation-symmetric rotor (15), which is connected to a hollow drive shaft (5), wherein the stator, the rotor and the hollow drive shaft are arranged concentrically about a vertical axis of rotation (17) of the rotor and the drive shaft, and the rotor executes a rotational movement about the axis of rotation inside the stator.

Claims

1. A device for generating gas bubbles in suspensions, which are contained in a tank (18), having a rotation-symmetric stator (16) and a rotation-symmetric rotor (15), which is connected to a hollow drive shaft (5), wherein the stator (16), the rotor (15) and the hollow drive shaft (5) are arranged concentrically about a vertical axis of rotation (17) of the rotor (15) and the drive shaft (5), and the rotor (15) executes a rotational movement about the axis of rotation (17) inside the stator (16), wherein the rotor (15) has, on its upper end, a plate (1), which is oriented perpendicular to the axis of rotation (17) and on which vanes (2, 3, 4) are arranged that are oriented perpendicular to this plate (1) and radially to the axis of rotation (17), wherein the radial extension of the vanes (2, 3, 4) is greatest in the region of the plate (1), the stator (16) is constructed as a cylindrical hollow body that projects axially beyond the rotor (15) on an upper side of the rotor, wherein a casing of the cylindrical hollow body consists of a plurality of strip-shaped, radially oriented baffles (9) and is arranged on a support device, and wherein the hollow body of the stator (16) is shaped in a concave manner at its inner circumferential surface (19) and the inner circumferential surface (19) has the same distance to the outer circumferential surface (20), the support device (23) has a bottom surface (13), a spacer (14) and a vortex breaker (24), the stator (16) is spaced from the bottom surface (13) by the spacer (14) of the vortex breaker (24), a top surface, opposite the bottom surface, of the stator (16) has an opening, which is constructed in such a manner that the rotor (15) can be passed through it and the opening is surrounded by a cover ring (8), which seals the baffles (9) in an axial direction, at least one opening (6) for the intake of air into the suspension is arranged on the hollow drive shaft (5) of the rotor (15), below the plate (1) of the rotor (15), in the region of the vanes (2, 3, 4), wherein the rotor (15) has said vanes (2,3,4), which extend from the plate (1) in an axial direction to varying distances, at least two vanes (3, 4) of the rotor (15), which are arranged in the circumferential direction of the drive shaft (5), have a radial distance r to the axis of rotation (17), a first portion of the baffles (9) of the stator (16) runs at an angle α of 30° to 60° to the axis of rotation and a second portion of the baffles (9) of the stator (16) runs at an angle α′ of −30° to −60° to the axis of rotation (17) and the angles α and α′ have the same absolute value, and the baffles (9) of the stator (16) are connected to each other.

2. The device according to claim 1, wherein an exterior contour of the vanes (2, 3, 4) continually decreases, in a straight-line or convex-curved manner, in said axial direction as the distance from the plate (1) increases.

3. The device according to claim 2, wherein the exterior contour of the vanes (2, 3, 4) continually decreases in a straight-line or convex-curved manner in the axial direction as the distance from the plate (1) increases.

4. The device according to claim 1, wherein the vanes comprise a first, a second, and a third partial quantity, wherein the second and third partial quantities of the vanes (3, 4) have a smaller extension in the axial direction than the first partial quantity of the vanes (2), which has the maximum dimension in the axial direction.

5. The device according to claim 4, wherein the second and third partial quantities of the vanes (3, 4) are constructed having equal or variable lengths in the axial direction.

6. The device according to claim 4, wherein the second and third partial quantities of the vanes (3, 4) are connected in a radial orientation to the drive shaft (5).

7. The device according to claim 4, wherein inside edges (22) of the second and third partial quantities of the vanes (3, 4) are constructed in a tapering manner, or in a manner so as to taper to a point, toward the axis of rotation (17).

8. The device according to claim 4, wherein bottom edges (21) of the second and third partial quantities of the vanes (3, 4) are inclined toward the air inlet openings (6) and thereby form an angle γ between 0° and 60° relative to the horizontal.

9. The device according to claim 4, wherein air guidance devices (7) are arranged in the region of the air inlet openings (6) and are inclined toward the bottom (13) and thereby form an angle ε between 20° and 60° relative to the axis of rotation.

10. The device according to claim 4, wherein a first partial quantity of the baffles (9) and a second partial quantity of the baffles (9) are of the same size and both partial quantities constitute a total quantity of baffles (9).

11. The device according to claim 1, wherein the distance r corresponds to between 30% and 70% of the radius R of the rotation-symmetric plate (1).

12. The device according to claim 1, wherein the hollow body of the stators (16) is shaped in a linear or convex manner at its outer circumferential surface (20).

13. The device according to claim 1, wherein the stator (16) consists of at least one stator ring (16 a, 16 b), which consists of the cover ring (8) and an intermediate ring (10) and the baffles (9) connecting the cover ring (8) and the intermediate ring (10).

14. The device according to claim 13, wherein intermediate rings (10a, b) or vertical divider plates (27a, 27b) are detachably connected to each other.

15. The device according to claim 1, wherein cover ring (8) of the stator (16) is oriented horizontally or inclined toward the rotor (15) and forms an angle β of between 30° and 90° to the axis of rotation (17) of the rotor (15).

16. The device according to claim 1, wherein the rotor (15) and the stator (16) are fully or partially provided with a wear-protection layer.

17. The device according to claim 16, wherein the wear-protection layer is a plastic coating or is constructed as a modification of a microstructure of a material of which the rotor (15) and stator (16) are made.

18. A method for generating bubbles comprising operating the device for generating gas bubbles according to claim 1 in a tank (18) of a flotation cell, having a rotor (15) and a stator (16) according to claim 1, wherein the rotor (15) and the stator (16) are arranged in the bottom third of the tank of the flotation cell.

Description

(1) The invention will be described below with reference to several embodiments and is represented graphically in the accompanying figures. The coordinate system used in the figures illustrates the orientation of the device within the suspension. The plane formed by the axes x and y is parallel to the surface of the suspension. The axis z is aligned normal to this plane.

(2) FIG. 1 shows a sectional view of a rotor-stator combination with a drive shaft, which is positioned on a support device. The elements required to drive the rotor and the surrounding tank of the flotation cell are not shown.

(3) FIG. 2 shows a side view of a rotor. The drive shaft is not shown.

(4) FIG. 3 illustrates the bottom side of the rotor of FIG. 2.

(5) FIG. 4 shows a sectional view A-A of the geometric relationships of the vanes of the rotor of FIG. 3

(6) FIG. 5 shows an alternative embodiment of the rotor with curved vanes.

(7) FIG. 6 illustrates the bottom side of the rotor of FIG. 5.

(8) FIG. 7 shows the central sectional view of a two-part embodiment of the stator, which is positioned on a support device.

(9) FIG. 8 shows a central sectional view of the stator of FIG. 7 and the geometric relationships of the baffles.

(10) FIG. 9 shows a central sectional view of the stator of FIG. 7 and the geometric relationships of the upper cover ring.

(11) FIG. 10 shows a side view of a vertically divisible stator. In this case, the detachable connection of the segments is not shown.

(12) FIG. 11 shows a side view of a horizontally divisible stator. To clarify the divisibility, the stator rings are shown spaced.

(13) FIG. 12 shows in a side view the vertically divisible stator of FIG. 11, in its individual segments.

(14) FIG. 13 shows a side view of an embodiment of the stator having linear circumferential surfaces

(15) A preferred embodiment of the device for generating gas bubbles is shown in FIG. 1 and consists essentially of a rotation-symmetric stator (16), which encloses a rotation-symmetric rotor (15) and is detachably connected to a support device (23). The stator is designed as a cylindrical hollow body and projects beyond the rotor (15) on its upper side. Furthermore, the rotor (15) projects beyond the stator (16) on its bottom side and is arranged at a distance d from the vortex breaker (24) positioned on the bottom (13) of the support device. The rotor (15) is connected to a hollow drive shaft (5) which is designed such that air can be introduced into the suspension through the air guidance channel (7) located inside the drive shaft (5) and via the air inlet openings (6). (29) indicates the flow direction of the suspension.

(16) The embodiment of the rotor (15) shown in FIG. 2 is particularly suitable if the service life of such components is to be increased, since the gas bubbles in the suspension can be generated independently of the direction of rotation of the rotor (15). The rotor (15) has at its upper end a plate (1) from which vanes (2,3,4) with different lengths in the axial direction, extend radially to the axis of rotation (17). Here, the exterior edges of the vanes (2,3,4) taper with increasing distance from the plate continuously in a linear or convexly-curved manner. Furthermore, it is shown that the vanes (2, 3, 4) extend differently in the axial direction. A first part of the vanes (2) extends over the entire length of the rotor. A second (3) and a third (4) part of the vanes is shorter than the first part (2) of the vanes, wherein a part of the vanes (4) is in turn shorter than the other part (3) and thus a stronger swirling of the suspension gas bubble mixture is generated.

(17) FIG. 3 shows the bottom side of a rotor (15) from the viewing direction B (see FIG. 2). Here it is shown that the vanes (2), which extend over the entire length of the rotor (15) are arranged in a cross shape around the axis of rotation (17) and are connected to the drive shaft. Furthermore, it is shown that the short vanes (3,4) are radially spaced from the drive shaft and that the inner edge (22) of these vanes (3,4) are sharp-edged and tapered in order to generate a large number of almost uniformly-distributed gas bubble diameters in the suspension.

(18) FIG. 4 shows in a side view the sectional view corresponding to the section A-A (see FIG. 4). The lower edges (21) of the short vanes (3,4) are inclined in the direction of the plate, and cover an angle γ of 23°. Furthermore, it is shown that the drive shaft (5) in the region of the short vanes (3,4) is formed so that the air guidance channels (7) deflect the air entering the suspension so that it impinges on the inner edges (22) of the short vanes (3, 4). The angle ε is 26°.

(19) FIG. 5 shows in a side view an alternative embodiment of the rotor (15) provided for rotation with a preferred direction of rotation. Here, the vanes (2,3,4) extend with different lengths in the axial direction of the plate (1). With respect to the radial, the vanes (2,3,4) have a curved circular path.

(20) FIG. 6 shows the view of the bottom side, corresponding to the viewing direction C (see FIG. 5), of the alternative embodiment of the rotor (15) with curved vanes (2, 3, 4). Furthermore, the direction of rotation (28) for this embodiment of the stator is indicated.

(21) FIG. 7 shows a sectional view of the stator (16) of the device for generating gas bubbles, which is releasably connected to a support device (23). In this preferred embodiment, the stator (16) consists of an upper stator ring (16a), wherein the cover ring (8) and the divisible intermediate ring of the upper stator ring (10a) surround a partial quantity of the baffles (9). Accordingly, the intermediate ring of the lower stator ring (10b) and the seal ring (12) enclose a further partial quantity of the baffles (9). In the overall view of the stator, the exterior edges (20) of the baffles (9) have a convex contour. The inner edges (19) of the baffles (9) are concave and uniformly spaced from the exterior edges (20). The intermediate rings (10a and 10b) are detachably connected to each other. Furthermore, the seal ring (12) and the spacers (14) of the support device (23) are releasably connected to each other.

(22) FIG. 8 shows a sectional view of the stator (16) of Fig. Here it is shown that a partial quantity of the baffles is arranged at an angle α of 25° and a second partial quantity of baffles (9) is arranged at an angle α′ of −25°. Furthermore, it is shown that the baffles intersect in the region of the intermediate rings (10a, 10b), the seal ring (12) and the cover ring (8).

(23) In FIG. 9, a preferred embodiment of the stator (16) is shown. It is shown that the upper cover ring (8) is inclined in the direction of the support device (23) and thereby forms an angle β of 62°.

(24) In FIG. 10 an exemplary embodiment of a vertically divisible stator (16) is shown in a side view. The vertically extending dividing plane divides the stator into a part (25) and a part (26) which are detachably connected to one another in the region of the vertically extending, divisible guide plates (27a, b). Furthermore, it is shown that the exterior circumferential surface (20) of the stator (16) tapers towards the intermediate ring (10) and is convex.

(25) FIG. 11 is a side view showing the stator (16) and the support device (23) showing the divisibility of the individual components composed of the upper stator ring (16a), the lower stator ring (16b) and the support device (23). The separation planes are located in each case in the region of the intermediate rings (10a, 10b) and between the seal ring (12) and spacers (14) of the support device (23).

(26) The vertically divisible stator (16) of FIG. 11, its two individual parts (25) and (26), as well as the support device (23) are shown in FIG. 12. In this case, the stator is subdivided by vertically arranged divider plates (27a, b), which are detachably connected to one another and thus enable a simpler mounting of the stator.

(27) Another alternative embodiment of the stator (16) is disclosed by FIG. 13. In this case, the rectilinear exterior circumferential surface (20) forms the exterior wall of a hollow cylinder.

REFERENCE NUMERALS

(28) 1 Plate 2 Rotor vane, long 3 Rotor vane 4 Rotor vane 5 Drive shaft 6 Air outlet opening 7 Air guidance channel 8 Cover ring 9 Stator baffles 10 Intermediate ring 10 a Divisible intermediate ring of the upper stator ring 10 b Divisible intermediate ring of the lower stator ring 12 Seal ring 13 Bottom surface of the stator 14 Spacer 15 Rotor 16 Stator 16 a Stator ring 16 b Stator ring 17 Axis of rotation 18 Tank of a flotation cell 19 Inner circumferential surface of the stator 20 Exterior circumferential surface of the stator 21 Bottom edge of the vanes 22 Inner edge of the vanes 23 Support device of the stator 24 Vortex breaker 25 Vertically divided stator part 26 Vertically divided stator part 27 Vertical divider plates 28 Direction of rotation of the rotor 29 Flow direction of the suspension