EP2163683B1 - Pulper with a screening sheet and uses of such a pulper - Google Patents

Abstract

The pulper (1) has an agitator (3) arranged on a filter metal sheet (2). A discharge unit (13) provided above the metal sheet, and another discharge unit (12) is provided below the metal sheet. Balls (11) are arranged above the metal sheet, where diameter of the balls is larger than holes of the metal sheet. The balls have a specific density greater than 1 and lesser than 2, and are made of PVC. The pulper has a space closably set below positive pressure. The holes of the sheet have a circular surface with size of 0.1 to 0.5 mm.

Description

The invention relates to a pulper with a screen plate, a stirrer arranged above, a first outlet above the screen plate and a drain below the screen plate. Moreover, the invention relates to different methods for using such a pulper.

Such pulpers are used for the treatment of paper residues, biological materials and a variety of other substances. Here, the substances are subjected to a grinding process and it different fractions are separated. The separation of the fractions is done on the one hand by the arrangement of the processes and on the other hand, the design and arrangement of the screen plate.

For example, the shows EP-A-1 826 314 Such a pulper with screen plates and a stirrer. Another pulper with balls in the pulper but without screen plate is in the US-A-2 912 174 shown.

Such pulpers are in various embodiments for many years in use and they have worked well.

The invention has for its object to further develop such pulpers and to provide methods for using such a pulper.

The arrangement of balls above the screen plate causes these balls to accelerate the processes in the pulper. Some of the balls have the function of a ball mill. However, depending on the size, weight, and material of the balls, the balls will give further positive results during treatment of residuals in the pulper.

Although the principle of the ball mill has long been known, so far no balls have been used in the pulper, since it is assumed that such balls are destroyed in the grinding process or have negative effects on the processes in the pulper.

Fortunately, it has been found that the use of balls in the pulper significantly speeds up the processes and thus the balls have a positive influence on the process in the pulper.

So that the balls do not float in the pulper, they should have a specific gravity that is above 1. For specific applications, the specific gravity may be less than 1, since the balls with the stirrer can also be conveyed into the material to be ground against their buoyancy.

Particularly good results could be achieved if the spheres have a specific gravity of less than 2.0. Too heavy balls can damage the screen plate and they can have a negative impact on the processes in the pulper due to attrition.

Particularly good results were achieved with spheres having a specific gravity between 1.3 and 1.8. For example, spheres of PVC with a specific gravity of about 1.4 are particularly suitable for the processes in the pulper.

The balls may have a lenticular or even angular surface. Depending on the application, the surface of the balls can be varied. However, particularly good results were achieved with a spherical spherical shape.

Particularly good results could be achieved with a pulper having a pressurizable closed space. This makes it possible to use an air cushion with an overpressure of 0.1 to 0.5 bar, such as 0.2 bar, above the liquid surface in the pulper.

In order to produce such an overpressure in the pulper, it is proposed that the pulper has a pulper vessel which can be filled to a level and the inlet and outlet extend in a region above this level. As a result, the liquid column in the inlet and in the outlet can serve to provide an overpressure in the pulper. By varying the height of inlet and outlet can thus be varied in a simple manner, the pressure in the pulper. In particular for the use of the pulper as a pressure sorter, it is proposed that the screen plate has holes with an area the size of a circular area of 0.1 to 0.5 mm.

For structural reasons, it is advantageous if the screen plate has a flat perforated plate. The pulper can thereby be used for de-staining, painting and sorting.

Depending on the application, it is advantageous if the perforated plate has slots. In this case, commonly used slotted plates can be used in the field of use of pulpers. For example, slits with a width of 0.1 to 0.2 mm and a length of one to several centimeters are suitable.

The object of the invention is also achieved with a use of such a pulper, in which chips and accompanying substances are treated in the pulper with the balls and the stirrer, in a hydrocyclone the balls are separated and the balls are returned to the pulper.

It is particularly advantageous if countercurrent washing is carried out in the hydrocyclone.

This process is preferably operated continuously to allow effective rapid treatment.

The pulper is particularly suitable as a deflaker and as a defibrillator.

Embodiments of various pulpers are in the FIGS. 1 to 5 shown.

Fig. 1

Schematisch einen Schnitt durch einen offenen Pulper mit Rührer,

Fig. 2

schematisch einen Schnitt durch einen Pulper mit Rührer und nach oben gerichteten Abzugsleitungen,

Fig. 3

schematisch einen Schnitt durch einen Pulper mit nach oben und unten gerichten Abzugsleitungen,

Fig. 4

einen schematischen Schnitt durch einen Pulper mit einem speziellen Rühr- und Mahlwerk,

Fig. 5

schematisch einen Schnitt durch einen geschlossenen Pulper und

Fig. 6

schematisch einen Schnitt durch einen geschlossenen Pulper mit einer senkrechten Austragswendel und

Fig. 7

schematisch einen Schnitt durch einen geschlossenen Pulper mit erhöhter Wassersäule.

It shows:

Fig. 1

Schematically a section through an open pulper with stirrer,

Fig. 2

1 is a schematic section through a pulper with stirrer and upwardly directed discharge lines;

Fig. 3

schematically a section through a pulper with up and down dishes deduction lines,

Fig. 4

a schematic section through a pulper with a special stirrer and grinder,

Fig. 5

schematically a section through a closed pulper and

Fig. 6

schematically a section through a closed pulper with a vertical Austragswendel and

Fig. 7

schematically a section through a closed pulper with increased water column.

A pulper 1 has a screen plate 2 and a stirrer 3 arranged above it. The stirrer 3 has a central spiral 4 and radially arranged painting elements 5, 6 which interact with counterparts 7, 8 on the pulper vessel 9.

At the lower end of the central spiral 4, the spiral increases to a stirring element 10, which serves to stir the arranged in the pulper balls 11 above the screen plate.

Through the screen plate 2 passing fibers can be removed through the tube 12, while various fractions can be deducted from above the screen plate 2 accumulating fibers through the screw tubes 13, 14 and 15, to optionally also the pulper can be added again. A slider 16 makes it possible to remove accumulating residues from the pulper on the screen plate.

Various arrangements of the spiral tubes are in the FIGS. 2 and 3 shown. While in FIG. 2 with two arranged at different heights screw tubes 17, 18 residues can be removed from the pulper, shows the FIG. 3 two screw tubes, of which a screw tube 19 removes residues up, while the other screw tube 20 removes residues down.

The FIG. 4 shows an alternative embodiment of a pulper 30 in which a milling device 31 is also provided in the edge region in order to produce a grinding process between moving vanes 32 and a static wall 33. This grinding process is still supported by 35 arranged above the screen plate balls 35.

At the in FIG. 5 shown pulper 40 is replaced by a cover 41 of a similar to that in FIG. 1 Pulpers shown in Pulpergefäß 42 allows pressure adjustment. As a result, a negative pressure in the pulper can be generated in order, for example, to counteract the drawing in of air toward the screen plate. Depending on the requirements but also an overpressure can be generated. The pressure is displayed with the manometer 43. In this embodiment, the supply and discharge lines 44, 45 are extended upward such that the liquid level in the lines can be varied in a particularly wide range. The liquid level in the lines can thereby also be above or below the liquid level in the pulper.

These lines can also be arranged vertically. The embodiment shown in Figure 6 of a pulper 50 therefore has a vertically arranged discharge line 51 with a built-in head coil as Begleitaustragswendel 52. This results in a very compact and thus inexpensive arrangement is achieved. In addition, the spiral 53 at the bottom 54 of the pulper 50 leads to a particularly favorable filling of the accompanying discharge spiral 52. The arranged at the upper end of the accompanying discharge spiral 52 horizontal coil 55 allows further transport and ejection into a container, not shown.

The in FIG. 7 Pulper 60 shown is essentially like the pulper in FIG FIG. 5 built up. However, in order to avoid entrainment of air during stirring, a tube 62 was attached above the pulper vessel 61. As a result, the water column above the screen plate 63 can be increased and a funnel formation during stirring can be reduced. At the upper end of this tube 62 is a Windkessel 64, which in turn can be held under pressure with a line 65. The pressure displayed on the pressure gauge 66 can thereby be easily regulated.

Claims (15)

1. A pulper (1) with a screening sheet (2), with a stirrer (3) disposed thereabove, with a first discharge located above said screening sheet (2) and with a second discharge (12) located underneath said screening sheet (2), characterized in that balls (11) the diameter of which is larger than the holes of the screening sheet (2) are disposed above said screening sheet (2).
2. The pulper as set forth in claim 1, characterized in that the balls (11) have a specific density of more than 1.0.
3. The pulper as set forth in any one of the previous claims, characterized in that the balls (11) have a specific density of less than 2.0.
4. The pulper as set forth in any one of the previous claims, characterized in that the balls (11) have a specific density ranging between 1.3 and 1.8.
5. The pulper as set forth in any one of the previous claims, characterized in that the balls (11) are made from PVC.
6. The pulper as set forth in any one of the previous claims, characterized in that the balls (11) have a spherical surface.
7. The pulper as set forth in any one of the previous claims, characterized in that the pulper has a closed chamber that can be pressurized.
8. The pulper as set forth in any one of the previous claims, characterized in that it has a vessel which can be filled up to a level and that intake and discharge extend in a region located above said level.
9. The pulper as set forth in any one of the previous claims, characterized in that the screening sheet (2) has holes with a surface having the size of a circular area of 0.1 to 0.5 mm.
10. The pulper as set forth in any one of the previous claims, characterized in that the screening sheet (2) has a planar perforated plate.
11. Use of a pulper (1) as set forth in any one of the previous claims, wherein shred and associated material are processed in the pulper (1) with the balls (11) and the stirrer (3), the balls (11) are separated in a hydrocyclone and the balls (11) are returned into the pulper (1).
12. Use as set forth in claim 11, characterized in that a countercurrent wash process is performed in the hydrocyclone.
13. Use as set forth in claim 11 or 12, characterized in that the method is operated continuously.
14. Use of a pulper as set forth in any one of the previous claims 1 through 10 as a deflaker.
15. Use of a pulper as set forth in any one of the previous claims 1 through 10 as a defibrillator.

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