US20020056532A1 - Method and apparatus for washing fiber pulp mixture - Google Patents

Method and apparatus for washing fiber pulp mixture Download PDF

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Publication number
US20020056532A1
US20020056532A1 US09/808,554 US80855401A US2002056532A1 US 20020056532 A1 US20020056532 A1 US 20020056532A1 US 80855401 A US80855401 A US 80855401A US 2002056532 A1 US2002056532 A1 US 2002056532A1
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US
United States
Prior art keywords
wires
fiber pulp
dewatering section
dewatering
pulp mixture
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
Application number
US09/808,554
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English (en)
Inventor
Vesa Juutinen
Jouko Hautala
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valmet Technologies Oy
Original Assignee
Metso Paper Oy
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Metso Paper Oy filed Critical Metso Paper Oy
Publication of US20020056532A1 publication Critical patent/US20020056532A1/en
Abandoned legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
    • D21D1/20—Methods of refining
    • D21D1/40—Washing the fibres
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
    • D21C9/06—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents in filters ; Washing of concentrated pulp, e.g. pulp mats, on filtering surfaces
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/66—Pulp catching, de-watering, or recovering; Re-use of pulp-water
    • D21F1/80—Pulp catching, de-watering, or recovering; Re-use of pulp-water using endless screening belts

Definitions

  • the invention relates to a method and an apparatus for washing fiber pulp, in which fiber pulp is fed into a dewatering section and water and, with it, ash and/or other impurities are removed through a wire running in the same direction as the fiber pulp in the dewatering section, wherein the fiber pulp being washed is fed into a dewatering section formed between two wires and the wires are arranged to run in such a way that the dewatering section converges from the feed end to the outlet end, whereby water and, with it, impurities are removed in the dewatering section through both wires, and after the dewatering section, the wires and the pulp between them are led to run along a curving surface in such a way that pressure caused by the tension of the wires and the centrifugal force produced by the curved movement cause the removal of any extra water from the pulp.
  • Fiber pulp such as recycled fiber
  • fiber pulp is washed while being processed.
  • water is removed from it in a manner that aims at removing particle-type material, such as ash, with the water while useful fibers are retained in the fiber pulp.
  • a problem with both apparatuses is the small fiber matter washing capacity per meter of width of the apparatus.
  • a further problem with both apparatuses is poor wire durability, because, in both solutions, the finer side of the wire is against the roll.
  • neither solution provides the possibility of substantially adjusting the level of dewatering, and thereby adjusting the quantity of fines lost during washing, except by changing wires.
  • a still further problem with both apparatuses is that the dry stuff content of the washed fiber material exiting the apparatus is relatively low and thus usually requires a separate concentration prior to further processing.
  • Yet another problem with both apparatuses is that they require a high wire speed, which is disadvantageous with respect to both energy consumption and wire durability.
  • the invention is characterized in that the pulp being washed is fed into a dewatering section between two wires, in which at least one of the wires is led to run in the dewatering section along a convex path such that the dewatering is substantially more efficient at the forward end of the dewatering section than at the tail end.
  • the fiber pulp coming out of the dewatering section between the wires is led together with both wires to run along a curved surface, such as the outer surface of a turning roll or a surface of a curved shoe, whereby the removal of any extra water is achieved by pressure caused by the tension of the wires and by centrifugal force produced by the curved movement.
  • the fiber pulp is preferably fed to a closed dewatering chamber through which the wires ran in a manner that produces a convergent dewatering section between the wires.
  • turbulence is caused in the fiber pulp before it is fed into the dewatering section, whereby dewatering and thus also washing is performed as efficiently as possible and as far as possible along the length of the dewatering section without causing layers of fibers to be deposited on top of the wires.
  • the dewatering in the beginning of the dewatering zone is performed in such a manner that the flow rate of the fiber pulp differs from the motion speed of the wires in the beginning of the dewatering section.
  • turbulence caused in the fiber pulp before it is fed into the dewatering section can be efficiently maintained for as long as possible.
  • the dewatering section is made so as to curve towards the inside in such a manner that its cross-profile decreases more rapidly at the forward end than at the tail end. This produces a very efficient dewatering, which combined with the dewatering performed by the turning roll results in preferably achieving a high enough dry stuff content in the washed fiber material for the purpose of further processing.
  • a further advantage of the invention is that when washing the fiber pulp, ash and other particle-type material can very efficiently be removed from the fiber pulp along with water while the fibers of desired length remain efficiently in the fiber pulp mixture.
  • a yet further advantage of the invention is that a sufficiently high concentration of the fiber pulp is achieved after washing without additional presses or corresponding mechanical apparatuses.
  • dewatering and thus also the washing result can be substantially adjusted with control valves or other control elements in the area of the dewatering chamber, which also improves the washing result and fines loss.
  • dewatering is adjusted in such a manner that more water per length of fiber pulp mixture in the motion direction is removed in the forward end than in the tail end of the dewatering zone.
  • dewatering is adjusted in such a manner that approximately the same amount of water or less per length of fiber pulp mixture in the motion direction is removed in the forward end than in the tail end of the dewatering zone.
  • the apparatus of the invention also enables additional dewatering by means of a curved surface, such as a turning roll, located after the dewatering section. No edge sealing is necessary after the actual dewatering section, because the clearance in the outlet end of the section is adjusted in such a manner that the dry stuff content of the fiber pulp mixture in the outlet end is already sufficiently high.
  • the actual additional dewatering is done based on wire tension and centrifugal force on the curved surface.
  • the apparatus of the invention provides considerable advantages in comparison with other corresponding apparatuses. Dewatering and washing with the apparatus of the invention occurs in two directions, which provides a considerable capacity increase in comparison with prior apparatuses of equivalent width.
  • the apparatus also preferably contains a separate turbulence element. With the apparatus, the flow rate of the fiber pulp mixture in the dewatering section is kept suitable in relation to the wire speed. Both factors thus contribute to effectively preventing the fiber pulp mixture from depositing onto the surfaces of the wires too early during the fiber pulp's progression along the dewatering section, thus maintaining a good washing result.
  • the washing result and fines loss can also effectively be adjusted by controlling the dewatering in different ways in the longitudinal direction of the apparatus.
  • FIG. 1 shows a schematic sectional side view of an embodiment of the apparatus of the invention
  • FIGS. 2 a and 2 b show schematically a structure of the apparatus of the invention after the outlet opening of the dewatering section and a detail of it,
  • FIG. 3 shows a schematic sectional side view of a second embodiment of the apparatus of the invention
  • FIG. 4 shows a sectional side view of a third embodiment of the apparatus of the invention.
  • FIG. 5 shows schematically the effect of washing on the fiber distribution of a fiber pulp implemented by the apparatus and method of the invention.
  • FIG. 1 shows a schematic sectional side view of an embodiment of an apparatus in accordance with the invention.
  • the apparatus comprises a first wire 1 and a second wire 2 , between which a dewatering section 3 is formed.
  • the first wire 1 runs as a closed loop around guide rolls 4 a to 4 d and the second wire 2 correspondingly around a turning roll 5 and guide rolls 6 a and 6 b .
  • the number and location of guide rolls can vary, as known to a person skilled in the art.
  • the fiber pulp mixture to be washed is fed into a feeder chamber 7 from which it is preferably fed for instance through turbulence generator 8 to the dewatering section 3 formed between the first and second wire 1 and 2 .
  • the dewatering section 3 On both sides of the dewatering section 3 , against the outer surfaces of the wires 1 and 2 , there are dewatering boxes 9 and 10 or the like, through which water is drained from the fiber pulp mixture in the dewatering section 3 , as schematically illustrated by arrows 9 a and 10 a .
  • the dewatering section 3 is preferably a closed chamber formed by sides and support structures between the sides, along which the wires 1 and 2 run inside the dewatering chamber.
  • the dewatering boxes 9 , 10 or the like are installed on the support structures in such a manner that the water draining through the wires runs through the support structures into the dewatering boxes or the like.
  • wire support structures which can be of perforated plate, various foil structures or the like, are generally known per se to a person skilled in the art and they or their operation, therefore, need not be described in greater detail.
  • the term “closed” as used in connection with the dewatering chamber refers specifically to a structure in which the fiber pulp and the water it contains cannot exit the dewatering section along other than the desired dewatering routes.
  • the fiber pulp mixture has to flow from the dewatering section 3 onward in the same direction as the wires 1 and 2 . Simultaneously, water is removed from it along the entire way. Dewatering occurs in the dewatering section for instance in such a manner that preferably more water per length of fiber pulp mixture in the motion direction is removed at the forward end of the dewatering section 3 , i.e., the incoming end of the fiber pulp, than at the tail end of the dewatering section 3 .
  • the turbulence can be maintained by adjusting the dewatering based on the speed ratio or difference between the mixture and the wires, such that the fibers stay suitably mixed without any significant deposition on the surfaces of the wires 1 and 2 .
  • a negative pressure forms on the left side of the turning roll 5 in the space between the wire 2 and the turning roll 5 where the wire 2 detaches from the roll.
  • This space is marked with reference number 12 in the figure. This causes the low pressure to draw the fiber pulp against the wire 2 and thus the fiber pulp is detached from the top wire 1 .
  • the dewatering distribution along the length of the dewatering section can be altered in many ways. For instance, if in the forward end of the dewatering section, water is drained from the fiber pulp mixture faster than the speed with which the cross-sectional area of the dewatering section decreases, the flow speed of the fiber pulp decreases in this area. Another consequence is that closer to the outlet end of the dewatering section, water is drained slower than the speed with which the cross-sectional area of the dewatering section decreases, which results in a fiber pulp mixture speed at the outlet opening which equals the motion speed of the wires.
  • FIG. 2 a shows schematically a structure of the apparatus of the invention immediately after the outlet opening of the dewatering section before the wires and the fiber pulp arrive at the turning roll 5 .
  • the figure shows how the dewatering zone is everywhere surrounded by either the higher or the lower support structure, such as cover part 3 a or 3 b or sides 3 c , and the wires 1 and 2 correspondingly press against the higher and the lower support structures.
  • the fiber pulp mixture fills the space between the wires 1 and 2 and the dewatering section from the wires towards the edges.
  • the first wire 1 higher in the figure is preferably slightly narrower than the lower second wire 2 .
  • FIG. 3 shows a sectional side view of a second embodiment corresponding to the embodiment of the apparatus in FIG. 1, except that a separate dewatering shoe 15 has been added to it between the dewatering section and the turning roll 5 , along which shoe the wires 1 and 2 run to remove water from the fiber pulp mixture.
  • the dewatering shoe 15 advantageously has a curved surface, preferably so that its curve is smaller than the curve of the turning roll 5 following it, or of any other corresponding curved surface. In this way, dry stuff content can be raised even further without complex and expensive presses or other corresponding apparatuses.
  • the figure shows pressure pulse elements, in this case separate strips 16 , located in the dewatering section at the second wire 2 .
  • These strips produce an alternating pressure pulse through the wire, in which one pulse part pushes the fiber pulp on the surface of the wire 2 away from the wire and a counter-directional pressure pulse causes suction towards the wire, whereby the fiber matter layer accumulating on the surface of the wires is broken up, thus considerably reducing its tendency to prevent or interfere with dewatering. Additionally, turbulence can be maintained in the dewatering section thus improving dewatering without flocking and layering on the wire surface.
  • various rotating pressure pulse elements or other solutions known in the art can be used to produce pressure pulses on one or both sides of the dewatering section.
  • FIG. 4 shows a third embodiment of the apparatus of the invention, in which the turning roll 5 is replaced by a curved shoe 17 around which the wires and the fiber pulp mixture turn.
  • the shoe can have a surface with strips, or be implemented in any other manner known per se, whereby water can also be sucked through the wire 2 , or strips can be used to produce suction to improve dewatering.
  • FIG. 5 shows schematically the effect of washing on the fiber distribution of a fiber pulp implemented by the apparatus and method of the invention.
  • the distribution of fibers of different lengths is measured by a measuring method known per se and the figure illustrates the proportion of the fibers of different lengths in the fiber pulp used in the test before and after washing.
  • I represents the proportion of the longest fibers
  • V the proportion of the fines and ash in the pulp.
  • a significant amount of parts in the V group i.e., ash and fines
  • the proportion of other fiber contents in the washed pulp is correspondingly higher.
  • the figure shows clearly that washing in accordance with the invention removes the undesirable components of the pulp, and the desirable fibers tend to remain in the pulp.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
US09/808,554 1998-09-14 2001-03-14 Method and apparatus for washing fiber pulp mixture Abandoned US20020056532A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI981974A FI114812B (sv) 1998-09-14 1998-09-14 Förfarande och anordning för tvättning av en fibermassablandning
FIFI981974 1998-09-14
PCT/FI1999/000751 WO2000015900A1 (en) 1998-09-14 1999-09-14 Method and apparatus for washing fibre pulp mixture

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1999/000751 Continuation WO2000015900A1 (en) 1998-09-14 1999-09-14 Method and apparatus for washing fibre pulp mixture

Publications (1)

Publication Number Publication Date
US20020056532A1 true US20020056532A1 (en) 2002-05-16

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ID=8552481

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Application Number Title Priority Date Filing Date
US09/808,554 Abandoned US20020056532A1 (en) 1998-09-14 2001-03-14 Method and apparatus for washing fiber pulp mixture

Country Status (12)

Country Link
US (1) US20020056532A1 (sv)
EP (1) EP1115945B1 (sv)
JP (1) JP2002525446A (sv)
KR (1) KR20010075065A (sv)
CN (1) CN1156629C (sv)
AT (1) ATE456700T1 (sv)
AU (1) AU5749399A (sv)
BR (1) BR9913695A (sv)
CA (1) CA2343957A1 (sv)
DE (1) DE69941984D1 (sv)
FI (1) FI114812B (sv)
WO (1) WO2000015900A1 (sv)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010046527A1 (en) * 2008-10-24 2010-04-29 Metso Paper, Inc. Forming section
CN116770615A (zh) * 2023-07-05 2023-09-19 合肥汇林包装有限公司 一种纸浆加工设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100858678B1 (ko) * 2006-09-01 2008-09-17 한국생산기술연구원 불순입자 제거 장치

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3142657C2 (de) * 1981-09-29 1985-06-20 Sulzer-Escher Wyss GmbH, 7980 Ravensburg Entwässerungsvorrichtung
AT376722B (de) * 1983-02-09 1984-12-27 Andritz Ag Maschf Entwaesserungsmaschine fuer zellstoff od. dgl. fasermaterial
AT402370B (de) 1991-06-13 1997-04-25 Andritz Patentverwaltung Doppelsiebentwässerungseinrichtung

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010046527A1 (en) * 2008-10-24 2010-04-29 Metso Paper, Inc. Forming section
CN116770615A (zh) * 2023-07-05 2023-09-19 合肥汇林包装有限公司 一种纸浆加工设备

Also Published As

Publication number Publication date
ATE456700T1 (de) 2010-02-15
JP2002525446A (ja) 2002-08-13
WO2000015900A1 (en) 2000-03-23
CN1156629C (zh) 2004-07-07
DE69941984D1 (de) 2010-03-18
EP1115945B1 (en) 2010-01-27
CN1318119A (zh) 2001-10-17
CA2343957A1 (en) 2000-03-23
FI114812B (sv) 2004-12-31
FI981974A (sv) 2000-03-15
FI981974A0 (sv) 1998-09-14
KR20010075065A (ko) 2001-08-09
EP1115945A1 (en) 2001-07-18
BR9913695A (pt) 2001-06-05
AU5749399A (en) 2000-04-03

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Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION