EP0250421B1 - A flat structure permeable to liquid, and a method for manufacturing such a structure - Google Patents

A flat structure permeable to liquid, and a method for manufacturing such a structure Download PDF

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Publication number
EP0250421B1
EP0250421B1 EP19860901874 EP86901874A EP0250421B1 EP 0250421 B1 EP0250421 B1 EP 0250421B1 EP 19860901874 EP19860901874 EP 19860901874 EP 86901874 A EP86901874 A EP 86901874A EP 0250421 B1 EP0250421 B1 EP 0250421B1
Authority
EP
European Patent Office
Prior art keywords
belt
press
holes
laterally
felt
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.)
Expired
Application number
EP19860901874
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0250421A1 (en
Inventor
Seppo Sorsa
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.)
Stowe Woodward Finland Oy
Original Assignee
Stowe Woodward Finland 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 Stowe Woodward Finland Oy filed Critical Stowe Woodward Finland Oy
Priority to AT86901874T priority Critical patent/ATE56766T1/de
Publication of EP0250421A1 publication Critical patent/EP0250421A1/en
Application granted granted Critical
Publication of EP0250421B1 publication Critical patent/EP0250421B1/en
Expired legal-status Critical Current

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Classifications

    • 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
    • D21F1/0027—Screen-cloths
    • D21F1/0063—Perforated sheets

Definitions

  • the present invention relates to a flat structure permeable to liquid, in particular to a press felt used in papermaking machines, and to a method for manufacturing such a structure.
  • the structure according to the invention is used primarily as a press felt, but it can also be used as a press wire, for example.
  • a wire is meant an endless fabric through which water is filtered from the stock.
  • the wires are in general made of phosphor-bronze or a synthetic fiber.
  • the fiber web which has been formed in the wire section of the papermaking machine still has a high moisture content, which is reduced in the wet press of the papermaking machine by pressing the web, together with one of several press felts, between rolls.
  • the main function of the wet pressing is thus to dewater the web, but its functions also include compacting the web and strengthening it in order to achieve sufficient wet strength.
  • Sufficient wet strength of the web is a prerequisite for the web being capable of being moved, without breaking, from the press section to the dryer section and further from one drying drum to another.
  • the wet press it is possible to use rolls of different types, such as plain, perforated, grooved or covered rolls. It is also possible to use a press wire between the press felt and the roll surface in order to improve the dewatering ability and to eliminate marking of the paper by the roll.
  • the primary function of the press felt is to receive the water extracted from the web. It is also a function of the felt to support the web in the press and to protect it from being damaged in the press.
  • the structure of the press felt plays a crucial role in the final quality of the paper.
  • An effective press felt is required to have a good dewatering ability, mechanical strength, a long usage life, and an ability to contribute to producing unmarked paper of an even quality.
  • needled press felts having a high synthetic fiber content are used.
  • these synthetic fibers are polyamide, polyester and polyacrylic nitrile fibers.
  • the properties of a completed felt can be adjusted by using fibers of different fineness and of different raw materials in the wad needled to the felt. It is possible to give the felt the desired properties by combining different types of wad layers.
  • achieving sufficient smoothness of the felt is a problem; endeavors have been made to improve the smoothness of felts by, for example, needling a thin layer of finer fibers on the web-side surface of the felt.
  • the press felt has a crucial effect on dewatering, and therefore its quality is a very important factor.
  • the aim is to use uncompressible, stiff felts with an open structure.
  • a felt which is too open may produce detrimental patterns in the web and an uneven distribution of pressure on the fibers of the web.
  • DE-C-628980 discloses the formation of a sieve which can be used for de-watering paper pulp, and which in contrast to the conventional metal sieve is formed of reinforced vulcanized natural or synthetic elastic rubber in which openings of increasing cross-section are provided. There is, however, no disclosure of the manner in which these tapering openings are formed.
  • EP-A2-0103376 discloses a paper drier belt preferably of metal, but possibly of plastics sheeting where relatively low temperatures are used in the drier, and the perforation is effected by mechanical post-treatment such as punching by mechanical or laser means, or a spark perforation technique.
  • the sheet thickness envisaged for the belt is from 0.1 to 0.15 mm.
  • the object of the present invention is to provide a flat structure permeable to liquid, for use especially as a press felt, a structure which has a good dewatering ability and a high mechanical strength, and by means of which an even distribution of pressure is achieved at the nip and the above-mentioned disadvantages are avoided. It is also an object of the invention to provide a simple structure which is easy to service, requires little maintenance, and has a long useful life. These objectives can be achieved by means of the structure according to the subject matter of claim 1 which starts in its precharacterising portion from the belt known from GB-A-995 620.
  • the body is made from castable non-thermoplastic polymers suitable for this purpose, preferably elastomers, such as casting urethane.
  • Casting urethane is a rubber-like material which is also called urethane rubber.
  • urethane rubber In addition to urethane rubber it is also possible to use other liquid rubbers, such as nitrile rubbers and silicone rubbers.
  • the castable polymers such as casting urethane, can easily be blended with polymeric additives such as epoxy, to form a uniform castable basic material.
  • the properties of the structure can, when so desired, be modified in various ways.
  • the mechanical properties such as stiffness, hardness and resistance to wear and flex, can be adjusted by selecting a suitable polymer.
  • the strength properties are improved by means of various reinforcement materials such as glass fiber, chopped fiber, monofilaments, multifilaments, and/or metal netting. It is also possible to use both woven and non-woven reinforcement materials. Synthetic fibers such as polyamide, aramide (“Kevlar”) and polyester fibers are typical raw materials.
  • the reinforcement materials are preferably fitted inside the body.
  • Casting urethane being a rubber-like material, has good mechanical-dynamic properties as the body material of the structure, and, in addition, at the casting stage it is highly reactive, so that it is easy to achieve a chemical bond between it and most reinforcement materials.
  • the dewatering ability of the structure can be improved and its elasticity can be adjusted by forming in the structure cavities and/or pores of different shapes and sizes; these cavities and pores may be open or closed.
  • the open porousness may also be such that the pores are progre- sively more open through the entire structure.
  • the surface properties of the structure as regards friction and release, can be adjusted to be those desired.
  • the properties of the structure can also be modified by forming a sandwich struture in which the different layers behave mechanically in different ways.
  • the web-side surface of the structure according to the invention is very smooth and microporous, and the dewatering ability of the structure is good.
  • a very even pressure is also achieved at the nip, and this even pressure contributes to the formation of paper of even and good quality.
  • elastic covering of the rolls is not necessary.
  • the application of the raw materials to the base is preferably done by casting, spreading or spraying.
  • the base must in general be treated with a lubricant so that the completed structure can be easily detached from the base.
  • the endless base is fitted between two rolls.
  • the endless base is fitted around a large diameter roll.
  • the circumferential surface of a large-diameter roll can also constitute the endless base.
  • the flat body made of castable polymer is indicated by reference numeral 1.
  • the body 1 is preferably made of urethane rubber.
  • the body 1 has conical holes 2.
  • the web-side surface 3 ( Figures 1 and 2) is microporous and very smooth.
  • the other surface, for its part, has pores which are clearly more open. Owing to this structure, the structure according to the invention, when used as a press felt or press wire, has a good dewatering ability and, furthermore, the holes 2 do not get easily clogged.
  • Figure 3 depicts a structure similar to that in Figure 1, except that it has been reinforced with a stratum of reinforcement material 4.
  • Various synthentic fibers, threads and fabrics, glass fibers, and metal wires and nettings are among suitable reinforcement materials.
  • Figure 4 depicts a structure similar to that in Figure 1, except that the structure has pores 5.
  • the pores may be opened or closed pores. Open pores make the structure more "song-like", thereby improving its dewatering ability. Closed pores, for their part, improve the elastic properties of the structure.
  • Figure 5 depicts a structure similar to that in Figure 4, except that the structure has a stratum of cast-in-place cavities 6 which interconnect the holes, and cavities which open into the holes.
  • the structure according to the invention may both be reinforced and contain pores.
  • a belt-like mold 7 is stretched between two rolls 9, the surface of the mold having conical spikes 8 the shape of which corresponds to the shape of the holes desired in the structure.
  • the raw materials of a polymeric material are applied to this "bed of nails" to produce a structure of desired thickness.
  • the raw material can be applied by casting, spreading, or spraying. For the final curing of the material, a heat treatment is usually necessary.
  • the completed structure is detached from the "bed of nails”.
  • the applying of the raw material is carried out in layers, the reinforcement material being placed between layers.
  • suitable chemicals such as volatile substances or water-soluble substances
  • these substances are added to the polymeric material during the manufacturing processes, these substances forming, under the effect of heat or water, pores in the structure.
  • water-soluble substances is common salt, the grain size of which determines the size of the pores.

Landscapes

  • Paper (AREA)
  • Materials For Medical Uses (AREA)
  • Filtering Materials (AREA)
EP19860901874 1985-03-01 1986-02-28 A flat structure permeable to liquid, and a method for manufacturing such a structure Expired EP0250421B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86901874T ATE56766T1 (de) 1985-03-01 1986-02-28 Fuer fluessigkeit durchlaessige flache struktur und herstellung derselben.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI850844A FI75893C (fi) 1985-03-01 1985-03-01 Skivformad vaetskegenomslaeppande struktur, och foerfarande foer tillverkning av densamma.
FI850844 1985-03-01

Publications (2)

Publication Number Publication Date
EP0250421A1 EP0250421A1 (en) 1988-01-07
EP0250421B1 true EP0250421B1 (en) 1990-09-19

Family

ID=8520452

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860901874 Expired EP0250421B1 (en) 1985-03-01 1986-02-28 A flat structure permeable to liquid, and a method for manufacturing such a structure

Country Status (10)

Country Link
EP (1) EP0250421B1 (da)
JP (1) JPS62502347A (da)
AU (1) AU575474B2 (da)
BR (1) BR8607073A (da)
CA (1) CA1295866C (da)
DE (1) DE3674402D1 (da)
DK (1) DK164125C (da)
FI (1) FI75893C (da)
SU (1) SU1671164A3 (da)
WO (1) WO1986005219A1 (da)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998035742A1 (en) * 1997-02-14 1998-08-20 Scapa Group Plc Filter press belt
US6544389B2 (en) 1999-08-20 2003-04-08 Astenjohnson, Inc. Molded modular link and a fabric made from a plurality thereof
US6569290B2 (en) 1999-08-20 2003-05-27 Astenjohnson, Inc. Bi-component molded modular link and a fabric made from a plurality thereof

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4657806A (en) * 1985-03-25 1987-04-14 Albany International Corp. Wet press papermakers felt
US4795480A (en) * 1986-12-10 1989-01-03 Albany International Corp. Papermakers felt with a resin matrix surface
US4740409A (en) * 1987-03-31 1988-04-26 Lefkowitz Leonard R Nonwoven fabric and method of manufacture
US5201978A (en) * 1988-04-08 1993-04-13 Beloit Technologies, Inc. Method of fabricating a blanket for an extended nip press
US5407563A (en) * 1990-05-24 1995-04-18 Brackett Green Limited Screening panels
GB9016619D0 (en) * 1990-07-28 1990-09-12 Scapa Group Plc Endless belts for extended nip dewatering presses
PT786551E (pt) * 1996-01-25 2000-06-30 Munzinger Conrad & Cie Ag Processo para a obtencao de uma banda de material plano
DK0786550T3 (da) * 1996-01-25 2000-06-26 Munzinger Conrad & Cie Ag Materialebane og fremgangsmåde til fremstilling deraf
JP4592230B2 (ja) * 2001-07-31 2010-12-01 日本フエルト株式会社 製紙用ベルト
US7128810B2 (en) * 2002-10-10 2006-10-31 Albany International Corp. Anti-rewet press fabric
US7407564B2 (en) * 2002-11-15 2008-08-05 Albany International Corp. Stratified press fabric
US7166196B1 (en) * 2002-12-31 2007-01-23 Albany International Corp. Method for manufacturing resin-impregnated endless belt structures for papermaking machines and similar industrial applications and belt
US7144479B2 (en) * 2003-04-16 2006-12-05 Albany International Corp. Method for increasing press fabric void volume by laser etching
US7144480B2 (en) * 2003-04-17 2006-12-05 Albany International Corp. Grooved belt with rebates
US7166195B2 (en) * 2003-07-15 2007-01-23 Albany International Corp. Grooved and perforated layer for use in papermakers' fabric
MX2011002620A (es) * 2008-09-11 2011-05-25 Albany Int Corp Banda permeable para la fabricacion de papel de seda, de toalla y materiales no tejidos.
CN102264970B (zh) * 2008-09-11 2015-04-01 阿尔巴尼国际公司 工业织物及其制造方法
US8454800B2 (en) 2009-01-28 2013-06-04 Albany International Corp. Industrial fabric for producing tissue and towel products, and method of making thereof
DE102010040089A1 (de) * 2010-09-01 2012-03-01 Voith Patent Gmbh Gelochte Folienbespannung
US8980062B2 (en) * 2012-12-26 2015-03-17 Albany International Corp. Industrial fabric comprising spirally wound material strips and method of making thereof
EP3198076B1 (en) 2014-09-25 2023-08-23 Albany International Corp. Multilayer belt for creping and structuring in a tissue making process
RU2687640C2 (ru) 2014-09-25 2019-05-15 Олбэни Интернешнл Корп. Многослойная лента для крепирования и структурирования в процессе изготовления основанного на целлюлозе продукта
US11098450B2 (en) 2017-10-27 2021-08-24 Albany International Corp. Methods for making improved cellulosic products using novel press felts and products made therefrom

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE628980C (de) * 1934-01-03 1936-04-20 Rudolf Haas Dr Ing Sieb fuer die Zwecke des Sortierens bzw. Entwaesserns bei der Herstellung von Papier o. dgl.
CH392239A (de) * 1960-07-23 1965-05-15 Heimbach Gmbh Thomas Josef Filterbahn zur Blattbildung und zur Stoffentwässerung und -trocknung bei Papiermaschinen oder dergleichen
CS198481B1 (en) * 1977-05-20 1980-06-30 Cestmir Balcar Multilayer felt,method of and apparatus for manufacturing same
SE429769B (sv) * 1980-04-01 1983-09-26 Nordiskafilt Ab Arkaggregat och sett att tillverka detsamma
DK331583A (da) * 1982-07-22 1984-01-23 Wiggins Teape Group Ltd Papirfremstillingsmaskine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998035742A1 (en) * 1997-02-14 1998-08-20 Scapa Group Plc Filter press belt
US6544389B2 (en) 1999-08-20 2003-04-08 Astenjohnson, Inc. Molded modular link and a fabric made from a plurality thereof
US6569290B2 (en) 1999-08-20 2003-05-27 Astenjohnson, Inc. Bi-component molded modular link and a fabric made from a plurality thereof

Also Published As

Publication number Publication date
DK522386D0 (da) 1986-10-31
JPS62502347A (ja) 1987-09-10
EP0250421A1 (en) 1988-01-07
FI850844L (fi) 1986-09-02
FI75893C (fi) 1988-08-08
DK164125B (da) 1992-05-11
AU5583086A (en) 1986-09-24
FI850844A0 (fi) 1985-03-01
AU575474B2 (en) 1988-07-28
BR8607073A (pt) 1988-02-09
FI75893B (fi) 1988-04-29
DE3674402D1 (de) 1990-10-25
SU1671164A3 (ru) 1991-08-15
CA1295866C (en) 1992-02-18
DK164125C (da) 1992-10-05
DK522386A (da) 1986-10-31
WO1986005219A1 (en) 1986-09-12

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