Centrifuge Comprising a Plurality of Centrifugal Drums Provided with Packets of Disks

Abstract

A centrifuge includes at least two centrifugal drums, each drum including a disc stack and each drum being rotatable about first and second axes of rotation. The first axis of rotation extends through a center of gravity of and is within each drum. The second axis of rotation is situated outside each drum.

Description

In the following, the invention will be described in detail by means of an embodiment with reference to the drawing.

FIG. 1 is a sectional view of a centrifuge according to the invention; and

FIG. 2 is a top view of the embodiment of FIG. 1.

FIG. 1 illustrates a centrifuge 1 having two centrifugal drums 2, 3 which are each rotatable about a first axis of rotation A1; here, the horizontal axis of rotation.

The first axes of rotation A1 extend through the centrifugal drums 2, 3, in each case as axes of symmetry in their center of gravity and are aligned here with one another.

The centrifugal drums 2, 3 are arranged opposite one another. However, the first axes of rotation do not have to be mutually aligned. They can also have a different mutual orientation, preferably a parallel mutual alignment.

Furthermore, the centrifugal drums 2, 3 can each also be rotated about a second axis of rotation A2, which here is situated outside the centrifugal drums 2, 3. Here, the two centrifugal drums 2 are rotated jointly “as a whole” about the second axis of rotation A1 situated outside the centrifugal drum 2—preferably in the joint center of gravity of the centrifugal drums 2,3—, which second axis of rotation A2 is situated perpendicular to the first axis of rotation A1 and crosses the latter.

Since, in each case, the first axes of rotation A1 are mutually aligned, and the second axis of rotation A2 is the same for both centrifugal drums 2,3, the construction is simple and clear. Thus, a single driving device 20 is sufficient for the rotation of both centrifugal drums 2, 3 about the second axis of rotation A2.

The centrifugal drums 2, 3 have a double-conical construction, two mutually oppositely oriented conical sections 4, 5 each being constructed at the end area, which is inside relative to the second axis of rotation A2, and at the end area, which is outside relative to the second axis of rotation A2, of the centrifugal drums and are in each case mutually connected by way of central cylindrical sections 6. In the area of sections 4, 5, 6, the centrifugal drums have a continuous basket shell.

At the outside ends of the outer conical sections 5, discharge openings 7 (nozzles) are constructed, particularly for a solids phase and are oriented concentrically to the first axis of rotation A1. Relative to the first axis of rotation A1, the outer conical sections 5 are each preferably conically at an acute angle, the angle of taper a with respect to the first axis of rotation amounting to 60° and less, so that wear effects as a result of solids exiting from the nozzles on the drum basket shell are largely avoided. This angle α is selected such that the solids can advantageously slide off on this angle.

In the direction of the second axis of rotation A2, the inner conical sections 4 are followed by cylindrical attachments 8 which are rotatably disposed by means of bearing systems, particularly by means of suitable ball bearings 9, in carrier elements 10, which absorb axial and radial forces. It is also conceivable to provide additional bearing systems (not shown here) in the outer area of the centrifugal drums (for example, following the conical areas on cylindrical attachments or the like (not shown here)).

One centric feeding pipe 11 respectively for the centrifugal material extends through the cylindrical attachments 8 and, for example, discharge ducts 12 arranged concentrically and/or parallel to these pipes, for discharging a lighter phase, such as a liquid phase, which ducts 12 may be connected toward the interior—with respect to the second axis of rotation A2—with additional inlet and discharge pipes (not shown here) (through the second axis of rotation). The function of the feeding pipe 11 and the discharge ducts 12 can also be reversed—with a corresponding modification of the connections). It is also conceivable to connect the two centrifugal drums fluidically behind one another.

Toward the interior, pulleys 13 are placed on the cylindrical attachments 8, which pulleys 13 are connected by way of driving belts 14 with output shafts 15 of first driving devices 16, particularly electric motors or hydraulic motors, which are preferably arranged parallel to the centrifugal drums 2 on opposite sides of the centrifugal drums 2 in order to implement an arrangement which is as free of imbalances as possible. Instead of a belt drive (for example, with flat belts, V-belts or toothed belts), chain drives or direct-acting transmissions, such as toothed gearings, or the like, are conceivable.

The two driving devices 16 as well as the carrier elements 10, which carry the centrifugal drums 2, 3, are arranged on a rotatable carrier-type ring 17, through whose center the second axis of rotation A2 extends, the centrifugal drums 2, 3 being above and the first driving devices 16 being situated below the ring 17. In addition, it is conceivable to arrange the centrifugal drums 2, 3 between an upper and a lower ring (not shown here) or to arrange the driving devices also above the ring 17 (here also not shown.) Finally, the two centrifugal drums 2, 3 may also have a joint driving device 16 for driving the centrifugal drums 2, 3 about the first axis of rotation A1; for example, a driving motor with two pulleys on a joint output shaft or the like.

By means of bearings 18, the horizontally aligned ring 17 is rotatably disposed on a base structure 19 and can be rotated by means of a second driving device 20 on the base structure 19. The bearing 18 absorbs the axial as well as the radial forces and can also be implemented in a different fashion.

One disc stack 21 respectively having conical discs is arranged concentrically with respect to the feeding pipe 10 in the two centrifugal drums 2, 3, which disc stack 21 can be provided with rising ducts 22 and can have a construction analogous to the disc stacks of separators.

During the operation, the two centrifugal drums 2, 3 rotate at a higher first rotational speed about the first axis of rotation A1. In this manner, a circumferential speed about the first axis of rotation A1 at the outer drum diameter can be reached which is known from decanters or, under certain circumstances, even from separators; for example, a circumferential speed of more than 80 m/sec. Whereas, the two centrifugal drums 2,3 preferably rotate about the second axis of rotation A2 at a lower circumferential speed (a subcritical operation is preferred). The term “subcritical operation” indicates a rotational speed below the first resonance frequency of the separator.

Centrifugal material in each case fed through the feeding pipe 11 enters into the centrifugal drums 2, 3, where liquids of different densities collect on different radii and are discharged through one or more discharge pipes or centripetal pumps, or the like. According to FIG. 1, only one liquid phase is discharged in each centrifugal drum 2, 3.

The solid phases collect in each case on the inner circumference of the centrifugal drums 2, 3, and, as a result of the rotation of the centrifugal drums 2, 3 about the second axis of rotation A2, move toward the outside in the latter, where they move in outer conical sections 5 to the discharge openings 7, move out of the centrifugal drums and are collected in a manner not shown here, for example, in an outer ring-type collecting device or the like.

It is noted here that it is a special advantage that an almost “automatic” solids discharge is implemented through the discharge opening 7 in the outer conical sections 5, without the requirement to provide auxiliary devices for the solids discharge, such as a screw, in the drum. In contrast to separator drums, the clogging of the nozzles can also be avoided. Although additional centrifugal forces act upon the system here, by means of a suitable compensation and a suitable distribution of the masses—particularly by a suitable -arrangement of the driving motors and by mass-balancing weights (not shown)—, these forces can be kept within comprehensible limits.

As a result of the fact that several centrifugal drums 2, 3 are provided, the capacity of each centrifuge is relatively large. It is even conceivable to arrange, instead of two centrifuges, also three, four or more centrifuges evenly distributed around the second axis of rotation on the circumference.

REFERENCE SYMBOLS

Centrifuge 1

centrifugal drums 2,3

conical sections 4, 5

cylindrical sections 6

discharge openings 7

cylindrical attachments 8

bearing 9

carrier elements 10

feeding pipe 11

discharge ducts 12

pulleys 13

driving belt 14

output shafts 15

1st driving device 16

ring 17

bearing 18

base structure 19

2nd driving device 20

disc 21

rising ducts 22

Claims

1. Centrifuge having at least one centrifugal drum, having a stack of discs (21), characterized in that a) the centrifuge has at least two centrifugal drums (2,3) which can each be rotated about two axes of rotation (A1, A2)b) one of the axes of rotation respectively extending through the center of gravity of the centrifugal drums such that one of the axes of rotation (A1) is in each case situated within the at least one or more centrifugal drum(s) and the other axis of rotation (A2) is preferably situated outside the centrifugal drum(s) (2, 3),c) one of the disc stacks (21) respectively being inserted into the drums.

2. Centrifuge according to claim 1, characterized in that the two axes of rotation extending through the center of gravity are oriented parallel to one another and, in particular, are aligned with one another.

3. Centrifuge according to claim 1 or 2, characterized in that the centrifugal drums (2, 3) have a continuous basket shell.

4. Centrifuge according to one of the preceding claims, characterized in that one of the axes of rotation (A1) is in each case situated inside the at least one or more centrifugal drum(s), and the other axis of rotation (A2) is situated outside the centrifugal drum(s) (2,3).

5. Centrifuge according to one of the preceding claims, characterized in that the maximal rotational speed of the centrifugal drums (2, 3) about the first axis of rotation (A1) is higher than the maximal rotational speed about the second axis of rotation (A2).

6. Centrifuge according to one of the preceding claims, characterized in that the two centrifugal drums (2, 3) are arranged opposite one another, and in that the first axes of rotation (A1) of the two centrifugal drums (2, 3) are aligned with one another.

7. Centrifuge according to one of the preceding claims, characterized in that the second axis of rotation (A2) is arranged perpendicular to the first axis of rotation (A1) and crosses the first axis of rotation (A1).

8. Centrifuge according to one of the preceding claims, characterized in that the two centrifugal drums (2, 3) have a double-conical construction, two mutually oppositely oriented conical sections (4, 5) each being constructed at the end area, which is inside relative to the second axis of rotation (A2), and at the end area, which is outside relative to the axis of rotation, of the centrifugal drums (2, 3).

9. Centrifugal drum according to one of the preceding claims, characterized in that the two conical sections (4, 5) of each centrifugal drum (2, 3) are mutually connected by way of central cylindrical sections (6).

10. Centrifuge according to one of the preceding claims, characterized in that, relative to the first axis of rotation (A1), the outer conical sections 5 are each preferably conically constructed at an acute angle, the angle of taper a with respect to the first axis of rotation (A1) amounting to 60E and less.

11. Centrifuge according to one of the preceding claims, characterized in that the disc stack (21) with conical discs (21) is in each case arranged concentrically with respect to the feeding pipe (10) in both centrifugal drums (2, 3).

12. Centrifuge according to one of the preceding claims, characterized in that the disc stack (21) has rising ducts (22).

13. Centrifuge according to one of the preceding claims, characterized in that, at the outer end of the outer conical sections (5), discharge openings (7) for a solid phase are constructed which are oriented concentrically with respect to the first axis of rotation (A1).

14. Centrifuge according to one of the preceding claims, characterized in that cylindrical attachments (8) are shaped onto the inner conical sections (4) toward the second axis of rotation (A2), which attachments (8) are disposed in the carrier elements (10) by means of bearings (9).

15. Centrifuge according to one of the preceding claims, characterized in that, in each case, one centric feeding pipe (11) for the centrifugal material and discharge ducts (12) extend through the cylindrical attachments (8).

16. Centrifuge according to one of the preceding claims, characterized in that each centrifugal drum (2, 3) has a first driving device (16) for driving the centrifugal drum (2, 3) about the first axis of rotation (A1).

17. Centrifuge according to one of the preceding claims, characterized in that the two centrifugal drums (2, 3) have a common driving device (16) for driving the centrifugal drum (2, 3) about the first axis of rotation (A1).

18. Centrifuge according to one of the preceding claims, characterized in that the two centrifugal drums (2, 3) as well as the two driving devices (16) are arranged on at least one ring (17) which is rotatably disposed.

19. Centrifuge according to one of the preceding claims, characterized in that the ring (17) is horizontally aligned and is rotatably disposed by means of bearings (18) on a base structure (19).

20. Centrifuge according to one of the preceding claims, characterized in that the ring (17) can be rotated on the base structure (19) by means of a second driving device (20).

21. Centrifuge according to one of the preceding claims, characterized in that the two centrifugal drums (2, 3) are connected behind one another with respect to the flow path of the centrifugal material.