WO2008041181A2

WO2008041181A2 - Belt for drying sludge

Info

Publication number: WO2008041181A2
Application number: PCT/IB2007/053999
Authority: WO
Inventors: Werner Hartmut Altmann; Reindert Buisman
Original assignee: The Warb Trust (No. 1 Trust 13337/99)
Priority date: 2006-10-02
Filing date: 2007-10-02
Publication date: 2008-04-10
Also published as: WO2008041181A3

Abstract

Apparatus (10) for dehydrating a mouldable sludge body (22) comprises a perforated steel belt (12) for receiving and holding the sludge body. The apparatus comprises a dehydration station (24) comprising a heating arrangement (26) located adjacent a first surface (12.1 ) of the belt and a suction arrangement (28) located adjacent an opposite surface (12.2) of the belt. The heating arrangement comprises one of a microwave emitting source and an infrared wave emitting source. A drive arrangement (14) causes the belt to move along a path (13) past the dehydration station. A moulding arrangement (30) upstream of the dehydration station forms alternate ridges and groves in the body, thereby to improve the efficiency of the drying at the dehydration station.

Description

STEEL BELT DRYING

INTRODUCTION AND BACKGROUND

This invention relates to apparatus and a method of dehydrating a sludge or the like.

Apparatus for drying or dehydrating a body of sludge or the like, is known. One embodiment of such an apparatus comprises a perforated belt for feeding the sludge past a dehydration station. The known apparatus and methods all suffer from the disadvantage that they are not efficient enough for at least some applications.

OBJECT OF THE INVENTION

Accordingly, it is an object of the present invention to provide an alternative apparatus and a method with which the applicant believes the aforementioned disadvantages may at least be alleviated.

SUMMARY OF THE INVENTION

According to the invention there is provided apparatus for dehydrating a sludge body, the apparatus comprising:

- a perforated belt for receiving and holding the sludge body; - a dehydration station comprising a heating arrangement located adjacent a first surface of the belt and a suction arrangement located adjacent an opposite surface of the belt; - the heating arrangement comprising at least one of a microwave emitting source and an infrared wave emitting source; and

- a drive arrangement for moving the belt and dehydration station relative to one another.

The belt may be an endless belt and the apparatus may comprise drive means for driving the belt along a path past the dehydration station.

The first surface may be a top surface, the opposite surface a bottom surface and the perforated belt may be a steel belt comprising warp and weft wires of steel.

The suction arrangement may comprise a fan, blower, vacuum pump or means utilizing airflow under pressure, to generate suction or a negative pressure adjacent the opposite surface of the belt. The infrared wave emitting source may be one or more of a long wave, medium wave or short wave infrared emitting source. Preferably the infrared wave emitting source is a source emitting infrared waves in the medium wave infrared band.

The apparatus may comprise means for adjusting a distance between the heating source and the first surface.

The apparatus may further comprise means for forming or moulding a corrugated profile comprising alternate ridges and grooves into the body. The forming or moulding means may be located upstream from the dehydration station. Longitudinal axes of the ridges and grooves may be parallel to a main axis of the belt, alternatively the axes may be transverse to the main axis of the belt.

The forming or moulding means may comprise a plate comprising serrations towards an end thereof, the plate extending transversely to the direction of movement.

In another embodiment the forming means may comprise an elongate roller mounted transversely to the direction of travel and comprising axially extending formations or teeth. The invention further includes within its scope means for forming corrugations in a body of sludge substantially as herein defined and/or described.

The invention still further includes within its scope a dehydration station as herein defined an/or described.

Yet further included within the scope of the present invention is a method of dehydrating a mouldable substance, the method comprising the steps of: forming corrugations in the substance; and - subjecting the formed substance to a dehydration station.

The formed substance and the dehydration station may be moved relative to one another. In a preferred embodiment, the substance is moved on a belt past the dehydration station.

The dehydration station may comprise a heating source and a suction arrangement and substance may be subjected to the heating source and the suction arrangement substantially simultaneously, alternatively first to the suction source and further alternatively, first to the heating source.

The substance may be moved along a path and subjected to the heat source from above and to the suction source from below.

BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMS The invention will now further be described, by way of example only, with reference to the accompanying diagrams wherein figure 1 is a diagrammatic side view of dehydrating apparatus according to the invention; figure 2 is a diagrammatic perspective view of part of the apparatus including a moulding arrangement in the form of a moulding plate forming part of the apparatus; figure 3 is a front elevation of a first embodiment of the plate; figure 4 is a front elevation of a second embodiment of the plate; figure 5 is a view similar to figure 2 with a second embodiment of the moulding arrangement; and figure 6 is a side view of the apparatus in figure 5.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

An example embodiment of a dehydration apparatus is generally designated by the reference numeral 10 in figure 1 . The apparatus 10 comprises an endless perforated belt 12, which may be a steel belt, comprising weft and warp elements or wires of steel. The belt is mounted on spaced rollers 14, 16 and 18, which in turn are mounted on a frame 15 of the apparatus. At least one of the rollers, typically roller 14, is driven by suitable drive means, such as an electric motor, to cause the belt to move clockwise along a closed path 13 about the rollers. Between rollers 16 and 14, the path has a straight section, which may be parallel to the horizontal.

The apparatus 10 comprises charge means 20 towards roller 16 for charging a sludge body 22 onto the belt 12. The sludge body deposited onto the moving belt is received, held and carried by the belt, to move from the charge means 20 towards roller 14.

The apparatus comprises a dehydration station 24 adjacent the path 13 and preferably in the straight section between roller 16 and driven roller 14, and more preferably towards driven roller 14. The dehydration station 24 comprises a heating arrangement comprising a heat source 26, which is preferably located spaced from one surface of the belt. In the example embodiment in figure 1 , the heat source is located spaced from a top surface 12.1 of the belt 12. The apparatus 10 may comprise means for adjusting the spacing D between the top surface 12.1 and the heat source 26. The heat source 26 may comprise one or more of an infrared source, a microwave source and a radio wave source. In a preferred embodiment, the heat source comprises an infrared source. The infrared source may be one or more of a long wave, medium wave or short wave infrared source. Preferably the infrared source is a source emitting infrared waves predominantly in the medium wave infrared band, that is between 2 Dm and 7 Dm, preferably including the range 3 Dm to 6 Dm.

The dehydration station 24 further comprises a suction arrangement 28 located adjacent an opposite surface of the belt. Preferably the suction arrangement is located adjacent a bottom surface 12.2 of the belt 12. The suction arrangement 28 may comprise any suitable means for generating suction adjacent the bottom surface 12.2 of the belt. In a preferred embodiment of the apparatus 10, the heat source 26 and the suction arrangement 28 are located opposite one another.

The apparatus 10 comprises a moulding arrangement 30 for forming or moulding corrugations 32 (shown in figures 2, 4 and 5) in the sludge body 22. The moulding arrangement is preferably located downstream of the charging means 20 and upstream from the dehydration station 24.

In the embodiments shown in figures 2, 3(a) and 3(b) the moulding means comprises a moulding plate 34. The moulding plate may be mounted on or form part of a wall of the charging means 20 facing the dehydration station 24 and preferably extends transversely to the path 13 of the belt. The plate 34 may comprise serrations 36 in a side 38 thereof facing the belt 12. The serrations may have any suitable shape, pattern or configuration to form corrugations 32 in the part of the body 22 moving on the belt towards dehydration station 24 and roller 14. Examples of suitable serrations 36 are shown in figures 3(a) and 3(b). It will be appreciated that the resulting corrugations 32 extend substantially axially in line with a main axis 12.3 of the belt 12.

In figures 4 and 5 there is shown a second embodiment of the moulding arrangement 30. In this example embodiment, the moulding arrangement comprises an elongate roller 40 comprising axially extending peripheral teeth 42. The roller is mounted on the frame 15 of the apparatus to extend transversely to the belt 12 and to traverse or span the belt 12. It will be appreciated that the corrugations formed by the roller 40 extend substantially transversely to the main axis 12.3 of the belt 12.

Referring again to figure 1 , in use, the sludge 22 is deposited at the charging means 20 onto the moving belt. The moving belt causes the sludge to move past the moulding means 30 to form the corrugations

32 in the sludge. The sludge 22 with corrugated profile is moved by the belt 12 past dehydration station 24. At the roller 14, the resulting dried body breaks up into pieces 22.1 to 22. n and drop from the belt, where the pieces are collected at 44.

Claims

1 . Apparatus for dehydrating a sludge body, the apparatus comprising: a perforated belt for receiving and holding the sludge body; - a dehydration station comprising a heating arrangement located adjacent a first surface of the belt and a suction arrangement located adjacent an opposite surface of the belt;

- the heating arrangement comprising one of a microwave emitting source and an infrared wave emitting source; and a drive arrangement for moving the belt and dehydration station relative to one another.

2. Apparatus as claimed in claim 1 wherein the belt is an endless belt and the drive arrangement comprises a driven wheel engaging the belt and for driving the belt along a path past the dehydration station.

3. Apparatus as claimed in claim 1 or claim 2 comprising a moulding arrangement upstream from the dehydration station and for forming a corrugated profile comprising alternate ridges and grooves into the body.

4. Apparatus as claimed in any one of the preceding claims wherein the perforated belt is a steel belt, the first surface is a top surface of the belt and the opposite surface is a bottom surface of the belt.

5. Apparatus as claimed in any one of the preceding claims wherein the suction arrangement comprises one of a vacuum pump and an arrangement utilizing airflow under pressure, to generate suction adjacent the opposite surface of the belt.

6. Apparatus as claimed in any one of claims 1 to 5 wherein the infrared wave emitting source is at least one of a long wave, medium wave or short wave infrared emitting source.

7. Apparatus as claimed in claim 6 wherein the infrared wave emitting source is a source emitting infrared waves predominantly in the medium wave infrared band.

8. Apparatus as claimed in any one of claims 1 to 7 comprising hight adjustment means connected to the heating source for adjusting a distance between the heating source and the first surface.

9. Apparatus as claimed in any one of claims 3 to 8 wherein longitudinal axes of the ridges formed into the body are parallel to a main axis of the belt.

10. Apparatus as claimed in claim 9 wherein the moulding arrangement comprises a plate comprising serrations towards an end thereof, the plate extending transversely to the direction of movement of the belt.

1 1 . Apparatus as claimed in any one of claims 3 to 8 wherein longitudinal axes of the ridges formed into the body are transverse to a main axis of the belt.

12. Apparatus as claimed in claim 1 1 wherein the moulding arrangement comprises an elongate roller extending transversely to the direction of travel of the belt and comprising axially extending peripheral teeth.

13. A method of dehydrating a mouldable substance, the method comprising the steps of:

- forming corrugations in the substance; and

- subjecting the formed substance to a dehydration station.

14. A method as claimed in claim 13 wherein the formed substance and the dehydration station are moved relative to one another.

15. A method as claimed in claim 14 wherein the substance is moved on a belt past the dehydration station.

16. A method as claimed in ay one of claims 13 to 15 wherein at the dehydration station the formed substance is subjected to a heating source and a suction arrangement.

17. A method as claimed in claim 16 wherein the substance is moved along a path and subjected to the heat source from above and to the suction arrangement from below.