EP0248625A2 - Filter press - Google Patents
Filter press Download PDFInfo
- Publication number
- EP0248625A2 EP0248625A2 EP87304835A EP87304835A EP0248625A2 EP 0248625 A2 EP0248625 A2 EP 0248625A2 EP 87304835 A EP87304835 A EP 87304835A EP 87304835 A EP87304835 A EP 87304835A EP 0248625 A2 EP0248625 A2 EP 0248625A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- wires
- filter press
- roll
- turning roll
- wire
- 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.)
- Withdrawn
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B9/00—Presses specially adapted for particular purposes
- B30B9/02—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material
- B30B9/24—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material using an endless pressing band
- B30B9/248—Means for sealing the press zone
Definitions
- the present invention relates to a filter press used for removing excess water from a slurry cake travelling between two opposite endless wires such as used for making paper or board.
- the filter press comprises a pre-pressing section and a post-pressing section, and between them a turning roll extending substantially over the whole width of the wires in a direction transverse to the direction of extension of the wires and disposed to change the running direction of the wires.
- the longitudinal tensile stressing of the wire increases in the middle of the wire and the tensile stressing at the edges may even be negative which means that the wire slackens at the edges whereby slurry may flow over the edges, especially at the pre-pressing section.
- edge sealings and "doctors" are provided at the straight portion of the wire.
- the object of the invention is to provide a filter press which avoids the problems discussed above and with which the speed of the filter press can be substantially improved.
- a filter press according to the invention is characterised in that the ends of the turning roll are,at least during operation of the filter press, closer to the wire furthest away from the turning roll than is the centre or central portion of the turning roll.
- a preferred embodiment of the invention is characterized by the feature that the diameter of the ends of the turning roll is greater than the diameter of the central portion of the roll.
- Another preferred embodiment of the invention is characterized in that substantially the whole turning roll is made of a flexible material.
- Yet another preferred embodiment of the invention is characterized in that the material of the ends of the turning roll is harder than the material of the central portion.
- Some of the most important advantages of the invention are that as the ends of the turning roll are lower than the central portion or closer to the wire further away from the roll, they create a greater wire tension at the edges of the wire than a turning roll having the same diameter from one end to the other.
- An increased wire tension at the edges of the wire presses the edges against each other at the curved wire portion and creates a sealing bag or enclosure sealed at the edges which prevents the slurry from flowing out over the edges.
- the sealing effect of a turning roll according to the invention is particularly effective at the pre-pressing section where the most difficult sealing problems occur today. Defining the web with a filter press according to the invention is remarkably easier than with prior art devices.
- Fig. 1 illustrates a typical filter press, in which a web 3 of slurry is formed between two oppositely rotatable wires 1 and 2.
- web 3 is feb between the wires from the left.
- the filter press comprises a pre-pressing section 4 and a post-pressing section 5 for removing excess water from the web.
- a turning roll 6, at which the webs are turned, is disposed between these sections.
- the turning rolls of the filter presses and used hitherto are stiff and have the same diameter from one end of the roll to the other.
- the uniform turning roll may be replaced with a turning roll 6 such as illustrated in Figs. 2 - 5.
- Fig. 2 illustrates a turning roll 6 made according to the invention.
- the diameter of ends 7 of the turning roll is greater than that of the central portion 8 of the roll.
- the cross section of the lower wire 2 remains constant and a web is formed on it with the upper wire curving towards the central portion 8 of the turning roll 6.
- the wires run into contact with each other and a bag of web is formed between the wires 1 and 2 from which the wet slurry cannot flow from between the edges of the wires and whereby defining of the web in the lateral direction is easy to control.
- Fig. 3 illustrates a turning roll 6 which also gives the web forming result described above.
- the ends 7 of the roll 6 are made of a harder material than the center portion 8 of the roll.
- the central portion is so soft that it yields and the upper wire forms the arch illustrated in the figure.
- Fig. 4 illustrates a turning roll 6 made according to the invention of a flexible material.
- the turning roll is cylindrical and its longitudinal axis is straight but during operation the material yields and the bending illustrated in the figure is achieved.
- the edges of the wires are pressed against each other and an enclosure bag is formed between the wires for the slurry 3.
- Fig. 5 illustrates yet another embodiment in which the diameter of the ends of the turning roll 6 is larger than that of the central portion of the roll.
- portions 9 between the ends 7 and the central portion 8 have the shape of a truncated cone. This embodiment also gives the desired result, i.e. the edges of the wires are sealed.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Filtration Of Liquid (AREA)
- Paper (AREA)
Abstract
Description
- The present invention relates to a filter press used for removing excess water from a slurry cake travelling between two opposite endless wires such as used for making paper or board. The filter press comprises a pre-pressing section and a post-pressing section, and between them a turning roll extending substantially over the whole width of the wires in a direction transverse to the direction of extension of the wires and disposed to change the running direction of the wires.
- As a web is formed between the wires the longitudinal tensile stressing of the wire increases in the middle of the wire and the tensile stressing at the edges may even be negative which means that the wire slackens at the edges whereby slurry may flow over the edges, especially at the pre-pressing section. To prevent this, edge sealings and "doctors" are provided at the straight portion of the wire.
- It is not possible to increase the speed of the machine and the speed of the wires unless the dry-solids content of the web after the pre-pressing section is adequate. Also trimming or defining the web is difficult because of the overflow of the slurry. Thus, the need to develop a new type of sealing the filter press has recently arisen.
- The object of the invention is to provide a filter press which avoids the problems discussed above and with which the speed of the filter press can be substantially improved. A filter press according to the invention is characterised in that the ends of the turning roll are,at least during operation of the filter press, closer to the wire furthest away from the turning roll than is the centre or central portion of the turning roll.
- A preferred embodiment of the invention is characterized by the feature that the diameter of the ends of the turning roll is greater than the diameter of the central portion of the roll.
- Another preferred embodiment of the invention is characterized in that substantially the whole turning roll is made of a flexible material.
- Yet another preferred embodiment of the invention is characterized in that the material of the ends of the turning roll is harder than the material of the central portion.
- Some of the most important advantages of the invention are that as the ends of the turning roll are lower than the central portion or closer to the wire further away from the roll, they create a greater wire tension at the edges of the wire than a turning roll having the same diameter from one end to the other. An increased wire tension at the edges of the wire presses the edges against each other at the curved wire portion and creates a sealing bag or enclosure sealed at the edges which prevents the slurry from flowing out over the edges. It has been discovered experimentally that the sealing effect of a turning roll according to the invention is particularly effective at the pre-pressing section where the most difficult sealing problems occur today. Defining the web with a filter press according to the invention is remarkably easier than with prior art devices.
- The invention is described in detail below, by way of example, with reference to the accompanying drawings, in which:-
- Fig. 1 is a schematic illustration of a filter press with a pre- and post-pressing section;
- Fig. 2 is a section along line II - II of Fig. 1;
- Fig. 3 is an illustration corresponding to Fig. 2 of another embodiment of the invention during operation of the press;
- Fig. 4 is an illustration corresponding to Fig. 2 of a third embodiment of the invention; and
- Fig. 5 is an illustration corresponding to Fig. 2 of a fourth embodiment of the invention.
- Fig. 1 illustrates a typical filter press, in which a
web 3 of slurry is formed between two oppositelyrotatable wires web 3 is feb between the wires from the left. The filter press comprises apre-pressing section 4 and apost-pressing section 5 for removing excess water from the web. Aturning roll 6, at which the webs are turned, is disposed between these sections. The turning rolls of the filter presses and used hitherto are stiff and have the same diameter from one end of the roll to the other. In the filter press according to the present invention, the uniform turning roll may be replaced with aturning roll 6 such as illustrated in Figs. 2 - 5. - Fig. 2 illustrates a turning
roll 6 made according to the invention. The diameter ofends 7 of the turning roll is greater than that of thecentral portion 8 of the roll. Whenwires turning roll 6, the wires are tensioned, naturally. The cross section of thelower wire 2 remains constant and a web is formed on it with the upper wire curving towards thecentral portion 8 of theturning roll 6. At theends 7 the wires run into contact with each other and a bag of web is formed between thewires - An even tension of
wire 2 can thus be achieved with the sealingturning roll 6 along the whole cross section of the wire and a cross section form sealing the edges of the wire between thewires - Fig. 3 illustrates a
turning roll 6 which also gives the web forming result described above. In this embodiment, theends 7 of theroll 6 are made of a harder material than thecenter portion 8 of the roll. The central portion is so soft that it yields and the upper wire forms the arch illustrated in the figure. - Fig. 4 illustrates a
turning roll 6 made according to the invention of a flexible material. When the filter press is not in operation the turning roll is cylindrical and its longitudinal axis is straight but during operation the material yields and the bending illustrated in the figure is achieved. Here again the edges of the wires are pressed against each other and an enclosure bag is formed between the wires for theslurry 3. - Fig. 5 illustrates yet another embodiment in which the diameter of the ends of the
turning roll 6 is larger than that of the central portion of the roll. In this embodiment,portions 9 between theends 7 and thecentral portion 8 have the shape of a truncated cone. This embodiment also gives the desired result, i.e. the edges of the wires are sealed. - It will be apparent to persons skilled in the art that the invention is not limited by the embodiments disclosed here as examples, only, but it can be modified within the scope of protection defined by the appended patent claims. The term "wire" relates to an endless belt of mesh or cloth as it is referred to sometimes.
Claims (4)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI862390A FI76855C (en) | 1986-06-04 | 1986-06-04 | Filtration Press. |
FI862390 | 1986-06-04 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0248625A2 true EP0248625A2 (en) | 1987-12-09 |
EP0248625A3 EP0248625A3 (en) | 1989-07-05 |
Family
ID=8522753
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP87304835A Withdrawn EP0248625A3 (en) | 1986-06-04 | 1987-06-01 | Filter press |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0248625A3 (en) |
FI (1) | FI76855C (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015167878A (en) * | 2014-03-05 | 2015-09-28 | 住友重機械エンバイロメント株式会社 | Belt press dehydrator and operation method of the same |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE285594C (en) * | ||||
FR1526592A (en) * | 1966-06-13 | 1968-05-24 | Hesser Ag Maschf | Fruit press |
FR2543276A1 (en) * | 1983-03-24 | 1984-09-28 | Stroemungsmasch Anst | Edge seal for dewatering machine screens |
-
1986
- 1986-06-04 FI FI862390A patent/FI76855C/en not_active IP Right Cessation
-
1987
- 1987-06-01 EP EP87304835A patent/EP0248625A3/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE285594C (en) * | ||||
FR1526592A (en) * | 1966-06-13 | 1968-05-24 | Hesser Ag Maschf | Fruit press |
FR2543276A1 (en) * | 1983-03-24 | 1984-09-28 | Stroemungsmasch Anst | Edge seal for dewatering machine screens |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015167878A (en) * | 2014-03-05 | 2015-09-28 | 住友重機械エンバイロメント株式会社 | Belt press dehydrator and operation method of the same |
Also Published As
Publication number | Publication date |
---|---|
FI76855C (en) | 1988-12-12 |
FI862390A0 (en) | 1986-06-04 |
FI76855B (en) | 1988-08-31 |
FI862390A (en) | 1987-12-05 |
EP0248625A3 (en) | 1989-07-05 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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AK | Designated contracting states |
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PUAL | Search report despatched |
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17P | Request for examination filed |
Effective date: 19891221 |
|
17Q | First examination report despatched |
Effective date: 19910313 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19910723 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: POEYRY, PEKKA Inventor name: HEINO, JUKKA Inventor name: KOHONEN, RAIMO |