CA2685390A1 - Screen - Google Patents
Screen Download PDFInfo
- Publication number
- CA2685390A1 CA2685390A1 CA002685390A CA2685390A CA2685390A1 CA 2685390 A1 CA2685390 A1 CA 2685390A1 CA 002685390 A CA002685390 A CA 002685390A CA 2685390 A CA2685390 A CA 2685390A CA 2685390 A1 CA2685390 A1 CA 2685390A1
- Authority
- CA
- Canada
- Prior art keywords
- screen
- layers
- recesses
- apertures
- front side
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000004519 manufacturing process Methods 0.000 claims abstract description 16
- 239000002657 fibrous material Substances 0.000 claims abstract description 15
- 239000000725 suspension Substances 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 claims description 5
- 238000012216 screening Methods 0.000 description 2
- 238000004026 adhesive bonding Methods 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000003698 laser cutting Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
- D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
- D21D5/02—Straining or screening the pulp
- D21D5/16—Cylinders and plates for screens
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Paper (AREA)
- Nonwoven Fabrics (AREA)
Abstract
The invention relates to a method for the production of a screen, and to a screen for the treatment of a fibrous material suspension suitable for the production of a fibrous material web, the screen comprising at least two screen layers (1) that are connected to each other and have passages, wherein at least part of the passages are disposed such that screen openings (3) extending through the screen are created. To this end, the production of the screen is to be simplified in that part of the passages are disposed such that recesses (4), which do not pass through the screen, are created on the front (2) of the screen, and that at least the passages forming the recesses (4) are introduced into the screen layers (1) before the connection thereof.
Description
Screen The invention relates to a method for the production of a screen and to a screen for the treatment of a fibrous material suspension suitable for the production of a fibrous material web, the screen comprising at least two screen layers that are connected to each other and have apertures, at least some of the apertures being arranged in such a way that the result is screen openings leading through the screen.
Screens of this type are preferably used for the wet screening of fibrous material suspensions in order to remove contraries present therein.
The characteristics of such a screen result substantially from the size, shape and number of screen openings located therein.
These screens are advantageously used in pulpers and separators for stock preparation.
In addition to a high throughput, the aim is also high resistance to the hydraulic pressure.
In order to be suitable for this purpose, in DE19547585 a screen having a supporting layer and a screening layer is proposed.
For an extremely wide range of reasons, however, it can also be necessary to provide the front side of the screen with recesses, which is normally even more complicated than the production of the screen openings.
The object of the invention is therefore to simplify the production of screens having recesses and their construction.
Screens of this type are preferably used for the wet screening of fibrous material suspensions in order to remove contraries present therein.
The characteristics of such a screen result substantially from the size, shape and number of screen openings located therein.
These screens are advantageously used in pulpers and separators for stock preparation.
In addition to a high throughput, the aim is also high resistance to the hydraulic pressure.
In order to be suitable for this purpose, in DE19547585 a screen having a supporting layer and a screening layer is proposed.
For an extremely wide range of reasons, however, it can also be necessary to provide the front side of the screen with recesses, which is normally even more complicated than the production of the screen openings.
The object of the invention is therefore to simplify the production of screens having recesses and their construction.
According to the invention, the object has been achieved in that some of the apertures are arranged in such a way that the result is recesses on the front side of the screen which do not pass through the screen.
For the production process, it is important in this case that at least the apertures forming the recesses are introduced into the screen layers before the latter are connected.
In this way, the recesses can be produced much more simply and usually also more accurately.
In order to be able to utilize the advantages comprehensively, as far as possible all the apertures should be introduced into the screen layers before the latter are connected. This is already much simpler because of the low thickness of the screen layers and is possible in particular by means of punching and laser cutting but, for example, also by means of milling, drilling, etching and so on.
Depending on the required stability of the screen, the configuration of the front side of the screen and of the openings, it may be advantageous if the screen is produced from or comprises four or more than four screen layers.
In particular, the cross-sectional profile of the screen openings, if, for example, starting from the front side, these widen in the direction of flow or run obliquely, with a relatively large number of screen layers, can be configured to be continuous, i.e. with no or small discontinuities.
In addition, the production of the apertures, in particular also in relation to the production of fine screens in the case of more and therefore thinner screen layers, is simpler and normally also more accurately possible.
On the other hand, a higher number of screen layers of course also increases the production costs.
The screen layers should be connected as flat as possible and this can be implemented in particular by brazing, welding, screw fixing or adhesive bonding.
For many applications, it is advantageous if the recesses form grooves or blind drilled holes.
Disruptive bars protruding beyond the front side can advantageously be fixed in the recesses. In addition, the disruptive bars can additionally be fixed to the screen, for example screwed on.
These disruptive bars can assist the through-flow effect of the screen, generate turbulence, reduce wear on the screen and form tearing edges.
They are primarily applied in arrangements in which a rotor is arranged in front of the front side of the screen. The interaction of rotor and wearing bars in this case contributes to conveying the contraries out of the center of the vortex.
In addition or alternatively, however, it may also be advantageous if the screen layers having the apertures forming the recesses are themselves formed as disruptive elements. In this way, the fitting of disruptive elements, in particular disruptive bars, can be dispensed with entirely.
In order to be able to ensure a sufficient function and stability of the disruptive elements but also a secure connection between the screen layers, the recesses should form between 3 and 50%, preferably between 5 and 30%, of the surface of the front side of the screen coming into contact with the fibrous material suspension.
In the interests of a long lifetime, irrespective of the configuration of the screen, the screen layer forming the front side of the screen should have a higher resistance to wear than other screen layers.
For the production, it has proven to be advantageous if the screen layers have a thickness between 1 and 20 mm, preferably between 1 and 10 mm.
In order to ensure sufficient stability, it is advantageous in this case if the screen has a total thickness between 4 and 100 mm, preferably between 6 and 50 mm.
The advantages in the production of the multilayer screen come to fruition optimally as compared with screens without screen layers if the screen openings have an extent between 1 and 20 mm, preferably between 4 and 20 mm, at the narrowest point.
The invention can be applied in flexible screens but in particular also in rigid screens.
In accordance with the demands on the stability and the wear, the screen layers should not consist of the same material, in order to minimize the material costs and the weight.
In the following text, the invention is to be explained in more detail by using two exemplary embodiments. In the appended drawing:
Figure 1 shows a partial section through a screen with disruptive bar 5;
For the production process, it is important in this case that at least the apertures forming the recesses are introduced into the screen layers before the latter are connected.
In this way, the recesses can be produced much more simply and usually also more accurately.
In order to be able to utilize the advantages comprehensively, as far as possible all the apertures should be introduced into the screen layers before the latter are connected. This is already much simpler because of the low thickness of the screen layers and is possible in particular by means of punching and laser cutting but, for example, also by means of milling, drilling, etching and so on.
Depending on the required stability of the screen, the configuration of the front side of the screen and of the openings, it may be advantageous if the screen is produced from or comprises four or more than four screen layers.
In particular, the cross-sectional profile of the screen openings, if, for example, starting from the front side, these widen in the direction of flow or run obliquely, with a relatively large number of screen layers, can be configured to be continuous, i.e. with no or small discontinuities.
In addition, the production of the apertures, in particular also in relation to the production of fine screens in the case of more and therefore thinner screen layers, is simpler and normally also more accurately possible.
On the other hand, a higher number of screen layers of course also increases the production costs.
The screen layers should be connected as flat as possible and this can be implemented in particular by brazing, welding, screw fixing or adhesive bonding.
For many applications, it is advantageous if the recesses form grooves or blind drilled holes.
Disruptive bars protruding beyond the front side can advantageously be fixed in the recesses. In addition, the disruptive bars can additionally be fixed to the screen, for example screwed on.
These disruptive bars can assist the through-flow effect of the screen, generate turbulence, reduce wear on the screen and form tearing edges.
They are primarily applied in arrangements in which a rotor is arranged in front of the front side of the screen. The interaction of rotor and wearing bars in this case contributes to conveying the contraries out of the center of the vortex.
In addition or alternatively, however, it may also be advantageous if the screen layers having the apertures forming the recesses are themselves formed as disruptive elements. In this way, the fitting of disruptive elements, in particular disruptive bars, can be dispensed with entirely.
In order to be able to ensure a sufficient function and stability of the disruptive elements but also a secure connection between the screen layers, the recesses should form between 3 and 50%, preferably between 5 and 30%, of the surface of the front side of the screen coming into contact with the fibrous material suspension.
In the interests of a long lifetime, irrespective of the configuration of the screen, the screen layer forming the front side of the screen should have a higher resistance to wear than other screen layers.
For the production, it has proven to be advantageous if the screen layers have a thickness between 1 and 20 mm, preferably between 1 and 10 mm.
In order to ensure sufficient stability, it is advantageous in this case if the screen has a total thickness between 4 and 100 mm, preferably between 6 and 50 mm.
The advantages in the production of the multilayer screen come to fruition optimally as compared with screens without screen layers if the screen openings have an extent between 1 and 20 mm, preferably between 4 and 20 mm, at the narrowest point.
The invention can be applied in flexible screens but in particular also in rigid screens.
In accordance with the demands on the stability and the wear, the screen layers should not consist of the same material, in order to minimize the material costs and the weight.
In the following text, the invention is to be explained in more detail by using two exemplary embodiments. In the appended drawing:
Figure 1 shows a partial section through a screen with disruptive bar 5;
figure 2 shows a plan view according to figure 1;
figure 3 shows a partial section through another screen having recesses 4, and figure 4 shows a plan view according to figure 3.
The common factor in all the embodiments is that the rigid, circular screen of a separator of an arrangement for preparing a fibrous material suspension for a paper machine comprises a plurality of screen layers 1. In this case, a rotating screen cleaner, not illustrated, is arranged in front of the screen in the flow direction.
These screen layers 1 have a thickness between 1 and 5 mm and are brazed to one another. Before the connection of the screen layers 1, however, apertures are punched into the latter and, in the screen, form recesses 4 on the front side 2 of the screen coming into contact with the fibrous material suspension, and penetrating screen openings 3. While the recesses 4 in figures 1 and 2 are formed only by the outer screen layer 1, this is done by the two outer screen layers 1 in figures 3 and 4.
Because of the low thickness of the screen layers 1, the apertures can be produced relatively simply and accurately.
In order to minimize the wear, the screen layer 1 forming the front side is formed from very wear-resistant material. The screen layers 1 lying underneath must ensure the stability of the screen and can in particular consist of less expensive and/or lighter-weight material.
The screen openings 3 have an extent between 4 and 20 mm at the narrowest point.
figure 3 shows a partial section through another screen having recesses 4, and figure 4 shows a plan view according to figure 3.
The common factor in all the embodiments is that the rigid, circular screen of a separator of an arrangement for preparing a fibrous material suspension for a paper machine comprises a plurality of screen layers 1. In this case, a rotating screen cleaner, not illustrated, is arranged in front of the screen in the flow direction.
These screen layers 1 have a thickness between 1 and 5 mm and are brazed to one another. Before the connection of the screen layers 1, however, apertures are punched into the latter and, in the screen, form recesses 4 on the front side 2 of the screen coming into contact with the fibrous material suspension, and penetrating screen openings 3. While the recesses 4 in figures 1 and 2 are formed only by the outer screen layer 1, this is done by the two outer screen layers 1 in figures 3 and 4.
Because of the low thickness of the screen layers 1, the apertures can be produced relatively simply and accurately.
In order to minimize the wear, the screen layer 1 forming the front side is formed from very wear-resistant material. The screen layers 1 lying underneath must ensure the stability of the screen and can in particular consist of less expensive and/or lighter-weight material.
The screen openings 3 have an extent between 4 and 20 mm at the narrowest point.
In the embodiment shown in figures 1 and 2, the screen comprises three screen layers 1 lying one above another and connected flat to one another. In this case, the recesses 4 are formed as grooves, into which disruptive bars 5 are plugged. These elongated disruptive bars 5 protrude beyond the front side 2 of the screen and are intended to reduce the wear of the screen, to generate turbulence, to clean contraries out of the center and to form working edges for the deflaking.
Via the recesses 4, the disruptive bars 5 are already provided with secure fixing to the screen. For the purpose of reinforcement, however, the disruptive bars 5 are further connected to the screen via screws 6.
The screen shown in figures 3 and 4 comprises four screen layers 1 lying one above another. Since, here, the recesses 4 are formed by two screen layers 1, these are also relatively deep.
However, it is important here that the recesses form between 5 and 30% of the surface of the front side 2 of the screen coming into contact with the fibrous material suspension. This large extent of the recesses 4 makes it possible for the screen layers 1 having the apertures forming the recesses 4 themselves to be able to act as disruptive elements. In this way, the complicated fitting of disruptive bars 5 can be dispensed with.
In addition, the screen openings 3 here can be found in and outside the recesses 4.
Via the recesses 4, the disruptive bars 5 are already provided with secure fixing to the screen. For the purpose of reinforcement, however, the disruptive bars 5 are further connected to the screen via screws 6.
The screen shown in figures 3 and 4 comprises four screen layers 1 lying one above another. Since, here, the recesses 4 are formed by two screen layers 1, these are also relatively deep.
However, it is important here that the recesses form between 5 and 30% of the surface of the front side 2 of the screen coming into contact with the fibrous material suspension. This large extent of the recesses 4 makes it possible for the screen layers 1 having the apertures forming the recesses 4 themselves to be able to act as disruptive elements. In this way, the complicated fitting of disruptive bars 5 can be dispensed with.
In addition, the screen openings 3 here can be found in and outside the recesses 4.
Claims (19)
1. A method for the production of a screen for the treatment of a fibrous material suspension suitable for the production of a fibrous material web, the screen comprising at least two screen layers (1) that are connected to each other and have apertures, at least some of the apertures being arranged in such a way that the result is screen openings (3) leading through the screen, characterized in that some of the apertures are arranged in such a way that the result is recesses (4) on the front side (2) of the screen which do not pass through the screen, and at least the apertures forming the recesses (4) are introduced into the screen layers (1) before the latter are connected.
2. The method as claimed in claim 1, characterized in that all the apertures are introduced into the screen layers (1) before the latter are connected.
3. The method as claimed in one of the preceding claims, characterized in that the screen layer (1) forming the front side (2) of the screen has a higher resistance to wear than other screen layers (1).
4. A screen for the treatment of a fibrous material suspension suitable for the production of a fibrous material web, the screen comprising at least two screen layers (1) that are connected to each other and have apertures, at least some of the apertures being arranged in such a way that the result is screen openings (3) leading through the screen, in particular produced in accordance with one of the preceding claims, characterized in that some of the apertures are arranged in such a way that the result is recesses (4) on the front side (2) of the screen which do not pass through the screen.
5. The screen as claimed in claim 4, characterized in that the screen comprises three screen layers (1).
6. The screen as claimed in claim 4, characterized in that the screen comprises four screen layers (1).
7. The screen as claimed in claim 4, characterized in that the screen comprises more than four screen layers (1).
8. The screen as claimed in one of claims 4 to 7, characterized in that the recesses (4) form grooves.
9. The screen as claimed in one of claims 4 to 8, characterized in that the recesses (4) form blind drilled holes.
10. The screen as claimed in one of claims 4 to 9, characterized in that disruptive bars (5) protruding beyond the front side (2) are fixed in the recesses (4).
11. The screen as claimed in one of claims 4 to 8, characterized in that the screen layers (1) having the apertures forming the recesses (4) are formed as disruptive elements.
12. The screen as claimed in claim 11, characterized in that the recesses form between 3 and 50% of the surface of the front side (2) of the screen coming into contact with the fibrous material suspension.
13. The screen as claimed in claim 11, characterized in that the recesses form between 5 and 30% of the surface of the front side (2) of the screen coming into contact with the fibrous material suspension.
14. The screen as claimed in one of claims 4 to 13, characterized in that the screen layer (1) forming the front side (2) of the screen has a higher resistance to wear than other screen layers (1).
15. The screen as claimed in one of claims 4 to 14, characterized in that the screen layers (1) have a thickness between 1 and 20 mm, preferably between 1 and 10 mm.
16. The screen as claimed in one of claims 4 to 15, characterized in that the screen has a total thickness between 4 and 100 mm, preferably between 6 and 50 mm.
17. The screen as claimed in one of claims 4 to 16, characterized in that the screen openings (3) have an extent between 1 and 20 mm, preferably between 4 and 20 mm, at the narrowest point.
18. The screen as claimed in one of claims 4 to 17, characterized in that it is rigid.
19. The screen as claimed in one of claims 4 to 18, characterized in that the screen layers (1) do not consist of the same material.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102007020325A DE102007020325B3 (en) | 2007-04-30 | 2007-04-30 | Process for producing a screen for the treatment of pulp suspensions suitable for paper production |
| DE102007020325.1 | 2007-04-30 | ||
| DE102007000640 | 2007-11-07 | ||
| DE102007000640.5 | 2007-11-07 | ||
| PCT/EP2008/051602 WO2008131976A1 (en) | 2007-04-30 | 2008-02-11 | Screen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2685390A1 true CA2685390A1 (en) | 2008-11-06 |
Family
ID=39414940
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002685390A Abandoned CA2685390A1 (en) | 2007-04-30 | 2008-02-11 | Screen |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP2152962A1 (en) |
| CA (1) | CA2685390A1 (en) |
| WO (1) | WO2008131976A1 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2515808Y2 (en) * | 1990-10-01 | 1996-10-30 | 相川鉄工株式会社 | Paper strainer |
| CA2132921A1 (en) * | 1993-10-28 | 1995-04-29 | William A. Gero | Finely perforated undulating screen cylinder |
| DE19547585A1 (en) * | 1995-12-20 | 1996-12-05 | Voith Sulzer Stoffaufbereitung | Sieving element |
| DE10065930B4 (en) * | 2000-12-22 | 2006-05-18 | Voith Paper Patent Gmbh | Method of making screens useful for wet screening of paper pulp suspensions |
-
2008
- 2008-02-11 CA CA002685390A patent/CA2685390A1/en not_active Abandoned
- 2008-02-11 WO PCT/EP2008/051602 patent/WO2008131976A1/en active Application Filing
- 2008-02-11 EP EP08708858A patent/EP2152962A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| WO2008131976A1 (en) | 2008-11-06 |
| EP2152962A1 (en) | 2010-02-17 |
| WO2008131976A8 (en) | 2010-04-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |
Effective date: 20140211 |