TOWER PRESS BELT

Abstract

A belt, for use in a tower press, comprises a first surface and a second surface having different properties such as differing permeability and/or particle capture properties.

Claims

1. A belt for use in a tower press, the belt comprising a first surface and a second surface having differing properties.

2. A belt according to claim 1, wherein the differing properties comprise differing permeability and/or particle capture properties.

3. A belt according to claim 1, wherein the belt is divided into at least two segments, and wherein when the belt is laid flat, each segment has an upper face and a lower face, such that the upper face of a first segment is the first surface and the lower face of this first segment is the second surface, and that the upper face of each segment adjacent to the first segment is the second surface and the lower face of each segment adjacent to the first segment is the first surface.

4. A belt according to claim 1, wherein the belt is divided into at least two segments, wherein when the belt is laid flat each segment has an upper face and a lower face, and wherein: (a) the upper faces of all segments alternate, from one end of the belt, between the first surface and the second surface; (b) the lower faces of all segments alternate, from the same end of the belt, between the second surface and the first surface.

5. A belt according to claim 3, wherein an RFID tag is present between at least one pair of adjacent segments.

6. A belt according to claim 5, wherein an RFID tag is present between each adjacent pair of segments.

7. A belt according to claim 1, wherein the belt is woven.

8. A belt according to claim 7, wherein the belt comprises interlaced warp and weft multifilament yarns having a linear density of 470-3300 dtex (g/10,000 m).

9. A belt according to claim 7, wherein the belt comprises interlaced warp and weft monofilament yarns having a diameter of 0.16-0.6 mm.

10. A belt according to claim 7, wherein the belt comprises interlaced warp and weft staple fibres having a metric count in the range of 2-10 Nm (m/g).

11. A belt according to claim 7, wherein the belt is woven to a twill or satin design.

12. A tower press comprising a belt according to claim 1.

13. A method of operating a tower press comprising rollers and a belt according to claim 1, wherein the method comprises: (a) aligning the belt such that a first surface of the belt is substantially always uppermost; (b) performing filtration using the tower press; (c) passing the belt over the rollers to remove cake build up; (d) optionally washing the belt using spray bars; (e) stopping the belt at a point at which the first surface of the belt is substantially always uppermost.

14. A method of operating a tower press according to claim 13, further comprising: (a) stopping the belt at a point at which the second surface of the belt is substantially always uppermost; (b) back-flushing the belt.

15. A method according to claim 13, wherein RFID tags are used to determine at what position to stop the belt.

Description

[0027] In order that the present invention may be more readily understood, a specific embodiment thereof will now be described by way of example only, with reference to the accompanying figures:

[0028] FIG. 1 shows a schematic diagram of a belt according to the invention.

[0029] FIG. 2 shows a tower press according to the invention, comprising the belt of FIG. 1.

[0030] In FIG. 1, a belt 1 comprises four segments 2. Each segment 2 comprises an upper face 3 and a lower face 4. The combination of four upper faces forms the first surface, and the combination of four lower faces forms the second surface. In the segment 2, depicted at the far right of the Figure, the upper face is a coarse draining surface and the lower surface is a fine filtration surface. In the adjacent segment, these surfaces are reversed, and indeed the surfaces alternate along the length of the belt.

[0031] FIG. 2 shows the belt of FIG. 1 when placed within a tower press comprising horizontal chambers 5 and rollers 6. As can be seen, within the horizontal stack of chambers the upper face 3 of each segment 2 is substantially always uppermost, and the lower face 4 of each segment 2 is substantially always lowermost and in contact with the horizontal chambers 5. The belt typically moves down the stack, and when it leaves the bottom chamber it runs over rollers 7 and rejoins the top chamber. A belt wash 8 is optionally provided after the belt leaves the bottom chamber.