DEVICE FOR GRANULATING SLUDGE

Abstract

A device for granulating sludge has a hollow-cylindrical die into which sludge to be granulated is to be injected and in which a stripper with at least one knife is rotatingly arranged. A knife holder holds at least one knife radially movably on the rotating stripper.

Claims

1. A device (10) for granulating sludge (12) comprising a hollow-cylindrical die (28) into which sludge (12) to be granulated is to be injected and in which a stripper (34) with at least one knife (36) is rotatingly arranged, wherein the at least one knife (36) is held substantially radially movably on the rotating stripper (34) by a knife holder (38).

2. The device for granulating sludge of claim 1, wherein the at least one knife (36) held substantially radially movably on the knife holder (38) is freely displaceable under its own weight.

3. The device for granulating sludge of claim 2, wherein the freely displaceable knife (36) is held on the knife holder (38) in the circumferential direction of the hollow-cylindrical die (28) with a clearance (46) of between 1% to 4% of the inside diameter (44) of the hollow-cylindrical die (28).

4. The device for granulating sludge of claim 1, wherein the knife holder (38) has a plurality of individual knives (36) arranged successively in the axial direction of the hollow-cylindrical die (28).

5. The device for granulating sludge of claim 4, wherein the individual knives (36) are arranged offset in the circumferential direction of the hollow-cylindrical die (28).

6. The device for granulating sludge of claim 1, wherein the at least one knife (36) held substantially radially movably has a knife height (48) that is between 95% to 98% of the inside diameter (44) of the hollow-cylindrical die (28).

7. The device for granulating sludge of claim 1, wherein the knife holder (38) has a tube (40) extending axially in the hollow-cylindrical die (28).

8. The device for granulating sludge of claim 7, wherein the tube (40) has at least one through opening (52) that extends transversely to the alignment of the at least one substantially radially movably held knife (36).

9. The device for granulating sludge of claim 1, wherein the at least one knife (36) held substantially radially movably is held at its two opposite end regions (58, 60) by the knife holder (38).

10. A method for operating the device (10) for granulating sludge (12) of claim 1, wherein the sludge (12) to be granulated is injected into a hollow-cylindrical die (28) and a stripper (34) is rotated in the die (28), comprising rotating the stripper (34) alternatingly with respect to its direction of rotation.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 is a perspective view of an exemplary embodiment of a device for granulating sludge according to the invention.

[0018] FIG. 2 is a section taken along line II-II in FIG. 1.

DETAILED DESCRIPTION

[0019] In FIGS. 1 and 2 there is illustrated a device 10 for granulating sludge 12, in which the sludge 12 is distributed by means of a main supply line 14, by a plurality of valves 16 connected thereto, into respectively associated individual supply lines 18. The individual supply lines 18 respectively lead to a place on the longitudinal extent of a supporting tube 20 at which they are fluid-conductingly coupled there by means of respectively one line connection 24. The supporting tube 20 is mounted stationarily by means of a tube holder 22. In the tube holder 22 there are embedded, inter alia, viewing windows 26 that allow an operator of the device 10 to look under the supporting tube 20.

[0020] Situated in the supporting tube 20 is a hollow-cylindrical die 28, the outside diameter of which is only slightly smaller than the inside diameter of the supporting tube 20. The hollow-cylindrical die 28 extends substantially over the entire length of the supporting tube 20 and has, in its upper portion in relation to FIG. 2, respective inlet openings 30 through which sludge 12 to be granulated can then be led from the individual supply lines 18 and the associated line connections 24 into the interior of the hollow-cylindrical die 28. Furthermore, at the lower portion of the die 28 in relation to FIG. 2, there is situated in the longitudinal direction thereof a row of outlet openings 32. The sludge 12 can then be led out of the die 28 again through these outlet openings 32, congruent openings also being situated in the supporting tube 20, although they are not shown in the present case.

[0021] In the interior of the hollow-cylindrical die 28 there is situated coaxially thereto a stripper 34 which rotates in the die 28 and thereby sweeps over the outlet openings 32 in such a manner that the sludge 12 forced out through these outlet openings 32 is portioned or granulated.

[0022] For this purpose, the stripper 34 is provided with a plurality of plate-shaped scrapers or knives 36 that are held, successively in the longitudinal or axial direction of the stripper 34 and offset relative to one another in the circumferential direction, on a knife holder 38 so as to be movable substantially in the radial direction. The knife holder 38 is formed by a tube 40 that extends likewise coaxially relative to the hollow-cylindrical die 28 and has an outside diameter of about ½ to ⅔ of the inside diameter 44 of the die 28. Formed in the tube 40 are respectively mutually diametrically opposite longitudinal slots 42, in which respectively one of the knives 36 is held with a clearance 46 in the circumferential direction of about ½ of the knife thickness or in the present case of between 2% and 3% of the inside diameter of the hollow-cylindrical die 28. The respective knife 36 is otherwise freely movable in the two associated longitudinal slots 42 of its knife holder 38 and is thus forced downwards in relation to FIG. 2 by its own weight and in the direction of the outlet openings 32 during the rotation of the stripper 34. The knives 36, when sweeping over the associated outlet openings 32, therefore press radially downwards due to their own weight. The knives 36 accordingly lie either directly on the inner surface of the hollow-cylindrical die 28 at the lower region thereof or they sweep over any sludge material which may have accumulated there at the edges of the outlet openings 32. The individual knives 36 have respectively a knife height 48 that is less than the inside diameter 44 of the hollow-cylindrical die 28, namely in the present case between 96% and 97% of the inside diameter 44 of the hollow-cylindrical die 28. The knives 36 therefore have, with respect to the inside diameter 44 of the hollow-cylindrical die 28, inside the latter likewise some play or freedom of movement, in order to be able to surmount sludge material that has banked up to a certain extent and not block the rotational movement of the stripper 34.

[0023] For the rotational or rotary movement of the stripper 34, a drive 50 is provided at one end of the supporting tube 20, by means of which drive the stripper 34 can be rotated alternatingly with respect to its direction of rotation. The stripper 34 can therefore be rotated both clockwise and anticlockwise. With this alternating rotation, it is possible to change the stripping direction of the knives 36 over the outlet openings 32. The outlet openings 32 are therefore, in relation to the sectional view according to FIG. 2, swept over first clockwise and then anticlockwise. In this way it is possible for sludge residues that have accumulated on one side of one of the outlet openings 32 to be removed on the return sweep of the associated knife 36.

[0024] It should further be noted that the tube 40 as well as the knives 36 have through openings 52 and 54, respectively. The through openings 52 pass through the wall of the tube 40 in its centre transversely to the alignment of the respectively adjacent knife 36. The through openings 54 also pass through the respective knife 36 centrally transversely to its disc plane 56.

[0025] The knives 36, held in such a way with play at their opposite end regions 58 and 60 by means of the tube 40 and its longitudinal slots 42, are moreover of V-shaped form in cross-section at these end regions 58 and 60, the two flanks or legs of the V-shape each facing the inner surface of the hollow-cylindrical die 28.

[0026] In conclusion, it should be noted that all the features that have been mentioned in the application documents and in particular in the dependent claims, despite their formal dependence on one or more specific claims, should also be accorded independent protection individually or in an any arbitrary combination.

LIST OF REFERENCE NUMERALS

[0027] 10 device [0028] 12 sludge [0029] 14 main supply line [0030] 16 valve [0031] 18 individual supply line [0032] 20 supporting tube [0033] 22 tube holder [0034] 24 line connection [0035] 26 viewing window [0036] 28 die [0037] 30 inlet opening in the die [0038] 32 outlet opening in the die [0039] 34 stripper [0040] 36 knife [0041] 38 knife holder [0042] 40 tube [0043] 42 longitudinal slot [0044] 44 inside diameter [0045] 46 clearance [0046] 48 knife height [0047] 50 drive [0048] 52 through opening of the tube [0049] 54 through opening of the knife [0050] 56 disc plane of the knife [0051] 58 end region [0052] 60 end region