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EP0651091A1 - Tamis circulaire à surface ondulée avec des perforations fines - Google Patents

Tamis circulaire à surface ondulée avec des perforations fines Download PDF

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Publication number
EP0651091A1
EP0651091A1 EP94630058A EP94630058A EP0651091A1 EP 0651091 A1 EP0651091 A1 EP 0651091A1 EP 94630058 A EP94630058 A EP 94630058A EP 94630058 A EP94630058 A EP 94630058A EP 0651091 A1 EP0651091 A1 EP 0651091A1
Authority
EP
European Patent Office
Prior art keywords
screen
layer
paper pulp
openings
layers
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Withdrawn
Application number
EP94630058A
Other languages
German (de)
English (en)
Inventor
William Anthony Gero
Frank J. Paskowski, Jr.
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.)
Beloit Technologies Inc
Original Assignee
Beloit Technologies Inc
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 Beloit Technologies Inc filed Critical Beloit Technologies Inc
Publication of EP0651091A1 publication Critical patent/EP0651091A1/fr
Withdrawn legal-status Critical Current

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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
    • 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
    • D21D5/06—Rotary screen-drums
    • D21D5/08—Rotary screen-drums combined with a rocking movement
    • D21D5/10—Rotary screen-drums combined with a rocking movement of the tank

Definitions

  • the present invention relates to improvements in pulp preparation apparatuses, and more particularly to apparatus for screening wood pulp to pass clean fibers and reject undesirable elements.
  • screens are utilized to separate acceptable fiber from undesirable constituents in a slurry.
  • a housing is provided with an inlet for pulp slurry which may have been prepared by cooking wood chips or by repulping secondary pulp fibers, so that the wood fibers are suspended in a slurry.
  • the slurry may include undesirable elements, such as knots, shives, particles of bark, dirt and other undesirable constituents.
  • the slurry flows adjacent a cylindrical screen, often referred to as a plate or basket, with the acceptable fibers flowing through the screen plate and the undesirable material remaining on the first side of the screen plate to flow out of a reject opening in the housing.
  • a rotor having pulse or turbulence generating structures normally is moved past the surface of the screen plate, to enhance the flow of slurry through the screen plate, and enhance the screening operation.
  • the screen has openings which are formed in the shape of holes or slots of a size required for the screening operation and in combinations for optimizing screening performance.
  • the screen plate must have screening openings of the proper size to pass the acceptable fibers and to prevent passage of the undesirable materials. Yet, with the necessity of these small openings, the screen plate must have sufficient strength to withstand the pressure differential across the surface, particularly when an arrangement is provided where pulsations are caused by moving members along the surface of the screen.
  • An object of the present invention is to provide still further improvements in screen plates which reduce manufacturing costs and yet provide a screening structure which has substantially improved strength over structures heretofore available.
  • a further object of the invention is to provide a screen structure which is capable of being made with closely spaced, fine screening holes, which normally would weaken the strength of the screen plate and yet which provides a large screening area and accomplishes substantial strength across the screening surface.
  • a further object of the invention is to provide a screen plate construction which accommodates a great variety of arrangements for providing the screening perforations in the plate.
  • a screen plate wherein relatively thin material is formed into an undulating shape or contour.
  • the relatively thin material can be utilized because multiple layers are arranged parallel to each other to, in essence, form a sandwich of layers.
  • the sandwich allows for the use of very thin material wherein screening perforations can be cut, such as with a laser beam, and yet the sandwiched material provides for unexpected strength, preventing any collapse of the screen material during continuous screening operation with pressure differentials across the screen.
  • the screen structure is capable of handling highly abrasive material, and provides a substantially increased screening area not fully dependent on the cylindrical size of the overall screen.
  • the plural layers of the screen assembly can be arranged so that the inner surface does the principal screening operation; or arranged so that, in a sandwich construction, the intermediate layer provides a screen plate to perform the screening operation, with outer layers having openings so as to freely pass the screened material and yet provide a monolithic sandwich layer which has substantial strength.
  • FIG. 1 illustrates a screening apparatus 8 wherein previously treated pulp is screened to remove undesirable elements such as shives, bark knots, particles of wood, dirt, glass, plastic and the like.
  • a screen plate assembly is generally shown at 10, defining in the apparatus 8 an interior chamber 11 where the pulp to be screened flows in and an exterior chamber 12 where the screened pulp flows out after passing through the screen plate assembly.
  • the assembly is enclosed in a housing 13 which has an inlet, not shown, for the entrance of pulp to be screened into the chamber 11, and an outlet, not shown, leading from the chamber 11 for the undesirable material such as the shives, bark and dirt.
  • the accepted pulp flows out through an outlet 14.
  • the screen plate assembly 10 is stationary within the housing 13, and for aid in passing the liquid stock with pulp through the screen plate, and to help inhibit plugging, pulsation generators 18 are mounted for rotation within the cylindrical screen plate assembly.
  • the pulsation generators 18 are supported on arms of a rotary driven shaft 19, and rotate in a clockwise direction, as viewed in Figure 1.
  • the pulsation generators in the form of the hydrofoils shown are merely illustrative of a suitable type, and it should be understood that the present invention can be used for screen plates with various types of pulse, turbulence and combination pulse and turbulence generating rotors.
  • the screen plate assembly 10 includes cylindrical screen sections 16 and 17 which, without support, are essentially flexible and require rigidifying or strengthening for use in the pressurized environment of screen apparatus 8.
  • the necessary support and strengthening is provided by end rings 20 and 20a and an intermediate support ring 21.
  • Each of the rings has grooves, such as illustrated by the grooves 23 and 24 in the ring 21 shown in Figure 2.
  • the grooves 23 and 24 are circular, to hold the screen sections in a substantially cylindrical shape.
  • the grooves 23 and 24 have a radial dimension substantially equal to the radial thickness of the shaped screen plates.
  • the plates are not necessarily segmented but may be arranged as a full annular assembly appropriately and adequately supported to remain stationary within the housing and to withstand the pressures of continuous flow and continuous movement of the pulse generator 18.
  • each of the shaped screen plates is positioned into the grooves in the end ring 20 or 20a and the intermediate ring 21, and the rings are pulled together to force the screen plates into the grooves.
  • axially extending rods 22 are provided, spaced circumferentially from each other, and the rods are provided at their ends with threads and nuts 22a, so that the nuts can be tightened to pull the end rings toward each other and force the ends of the screen plates into the grooves.
  • the grooves are preferably tapered so that the slot becomes narrower in a direction toward the bottom of the groove, as indicated by the illustration of Figure 2.
  • the screen plates When the nuts are threaded onto the rods, the screen plates are pushed tightly into the tapered grooves, so that the screen plates are held firmly in a fixed position, circumferentially.
  • the screens can be longer or shorter, or even greater in number, and additional reinforcing intermediate rings such as 21 may be employed between the ends of each of the adjacent screen plate sections.
  • Screening openings are provided in the screen plates, such as shown at 25 in Figure 2, which is primarily a schematic showing of the opening inasmuch as the screen plates have a unique construction, with varying arrangements for the openings 25 such as will be described in connection with Figures 3 through 6.
  • a screen structure 26 is comprised of multiple layers.
  • a first layer 27 faces the incoming pulp. This layer is the inner layer of an outward flowing screen, or the outer layer of an inwardly flowing screen, as one skilled in the art will recognize.
  • the first layer 27 is juxtaposed against and supported by a second layer 28.
  • the screen shown is an outwardly flowing screen and the first layer described herein is the inner layer, with the second layer being the outer layer.
  • the inner layer is provided with a series of screen perforations 29, preferably evenly distributed over the area of the inner layer 27.
  • the outer layer 28 has a series of flow passage holes 30, which are arranged so that the pulp being screened can continue flow past the outer layer to the opposite side of the screen. Thus, on the inner side of the inner layer will remain the undesirable material, to flow out of the rejects opening in the housing.
  • the flow through the multilayered screen will consist of the clean fibers. So that a substantially unimpeded flow occurs, the larger openings 30 in the outer layer 28, Figure 4, are arranged so that they align with a maximum number of screening perforations 29 of the first layer 27.
  • the outer layer has holes 30 which register with 5 of the smaller screening holes 29, but it will be understood that other arrangements can be employed, so that the larger openings 30 register with any number of perforations 29.
  • the function of the outer layer 28 is to reinforce or support the inner layer, so that a principal requirement of the outer layer is one of strength.
  • the outer layer may be thicker than the inner layer, or may be made of different material, to provide the necessary strength. The outer layer affords this strength even though the openings are provided to permit the flow of clean, acceptable fibers.
  • the sandwich or combination of layers is formed in an undulated shape.
  • these layers are formed with their individual holes before they are joined, and then are joined to each other and shaped in the undulating shape in unison. This insures a continued surface-to-surface contact for maximum strength and the maximum support function afforded by the outer layer 28.
  • the undulations are shaped in smooth curvatures to give maximum strength and to afford maximum screening surface area.
  • the layers are formed with ribs or crowns 31 facing inwardly, similar ribs or crowns 33 facing outwardly and vertical walls 32 and 34 to join the inner crown or ribs 31 with outer crowns or ribs 33. This arrangement will provide a multilayered screen of superior strength and of exceptional screening capacity.
  • a screen structure is formed with a strong reinforcing inner layer 44 and a strong reinforcing outer layer 45. Between the layers is sandwiched a screening layer which consists primarily of a fine mesh screen 47 of a size to perform the screening operation.
  • the fine mesh screen does not have substantial strength, but as will be seen, the only area of the screen which is exposed is through openings 51 and 52 in the inner and outer layers respectively.
  • the openings are preferably formed as circular holes for maximum strength and afford a substantial screening area.
  • the layers are assembled by the holes first being formed in the inner and outer layers 44 and 45, which are then placed with the screen sandwiched therebetween, and shaped or bent to the undulations illustrated in the drawing, Figure 5.
  • the undulations are preferably curved to form inner ribs and outer ribs joined by straight wall areas as described for Figure 3. This structural arrangement affords very substantial strength, as well as providing good screening area, while allowing very fine perforation of the screening layer 47.
  • the multilayered screen assembly will preferably be arranged in cylindrical form, whether in one piece or in sectional plates.
  • the pulse generators will be moved past the inner surface, that is, past the inner layer 27 in the structure of Figure 3 and the inner layer 44 of Figure 5.
  • the stock flowing into the cylinder of the screen assembly will be screened, with the clean fibers passing through the screening structure and out toward the outer side of the screen plate.
  • the undesirable materials will remain inside, to flow toward the reject opening.
  • the composite screen structures of Figures 3 and 5 preferably are formed by first arranging flat sheets and providing the openings therethrough. The flat sheets are then brought together in sandwich fashion and bent into the undulating shape shown in the Figures or into other desirable shapes. The undulating shaped screens are then arranged in cylindrical form, fully supported and positioned in the housing of Figure 1 for a continuous screening operation.
  • the reinforcing layers can be constructed of a material which provides the maximum strength, and the screening layers can be made very thin to provide well defined openings of a uniform and correct size for the screening operation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Filtration Of Liquid (AREA)
  • Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
EP94630058A 1993-10-28 1994-10-06 Tamis circulaire à surface ondulée avec des perforations fines Withdrawn EP0651091A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US14495893A 1993-10-28 1993-10-28
US144958 1993-10-28

Publications (1)

Publication Number Publication Date
EP0651091A1 true EP0651091A1 (fr) 1995-05-03

Family

ID=22510944

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94630058A Withdrawn EP0651091A1 (fr) 1993-10-28 1994-10-06 Tamis circulaire à surface ondulée avec des perforations fines

Country Status (6)

Country Link
EP (1) EP0651091A1 (fr)
JP (1) JPH07189158A (fr)
KR (1) KR950011762A (fr)
BR (1) BR9404222A (fr)
CA (1) CA2132921A1 (fr)
FI (1) FI945073L (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999061697A1 (fr) * 1998-05-29 1999-12-02 J & L Fiber Services Inc. Support de filtration et passage de filtration
WO2008131976A1 (fr) * 2007-04-30 2008-11-06 Voith Patent Gmbh Tamis
WO2008131974A1 (fr) * 2007-04-30 2008-11-06 Voith Patent Gmbh Procédé de fabrication d'un classeur, en particulier d'un classeur rigide pour le traitement de suspensions de matières fibreuses convenant à la fabrication du papier
DE102008059709A1 (de) 2008-11-29 2010-06-02 Voith Patent Gmbh Herstellung eines Siebes, insbesondere eines starren Siebes sowie Sieb, hergestellt nach einem derartigen Verfahren
CN101974864A (zh) * 2010-11-10 2011-02-16 天津市恒脉机电科技有限公司 一种螺旋挤浆机的筛网和包含该筛网的螺旋挤浆机
WO2012079917A3 (fr) * 2010-12-16 2013-02-14 Voith Patent Gmbh Tamis
CN114146478A (zh) * 2021-11-03 2022-03-08 宁波市自来水有限公司 一种原水管道用垃圾过滤筒

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100825981B1 (ko) * 2008-02-20 2008-04-28 김인규 데브리스 필터 시스템을 위한 스크린장치
KR101662378B1 (ko) * 2014-03-14 2016-10-04 박성배 분뇨 고액 분리장치
JP7277122B2 (ja) * 2018-12-10 2023-05-18 フォイト パテント ゲゼルシャフト ミット ベシュレンクテル ハフツング スクリーンバスケット

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE252334C (fr) *
WO1987004474A1 (fr) * 1986-01-22 1987-07-30 A. Ahlstrom Corporation Cylindre criblant
DE3638408A1 (de) * 1986-11-11 1988-05-19 Hett Alexander Masch Giess Verfahren zum trennen von stoerstoffen und wiederverwendbaren gustoffen, insbesondere von brauchbaren faserstoffen, aus mit feststoffen versetzten fluessigkeiten und vorrichtung zur durchfuehrung des verfahrens
US4954249A (en) * 1988-06-10 1990-09-04 Beloit Corporation Wave screen plate
EP0471195A1 (fr) * 1990-08-16 1992-02-19 CAE Investments B.V. Toiles et techniques de fabrications

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6420278A (en) * 1987-07-13 1989-01-24 Fuji Photo Film Co Ltd Ink jet recording fluid

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE252334C (fr) *
WO1987004474A1 (fr) * 1986-01-22 1987-07-30 A. Ahlstrom Corporation Cylindre criblant
DE3638408A1 (de) * 1986-11-11 1988-05-19 Hett Alexander Masch Giess Verfahren zum trennen von stoerstoffen und wiederverwendbaren gustoffen, insbesondere von brauchbaren faserstoffen, aus mit feststoffen versetzten fluessigkeiten und vorrichtung zur durchfuehrung des verfahrens
US4954249A (en) * 1988-06-10 1990-09-04 Beloit Corporation Wave screen plate
EP0471195A1 (fr) * 1990-08-16 1992-02-19 CAE Investments B.V. Toiles et techniques de fabrications

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999061697A1 (fr) * 1998-05-29 1999-12-02 J & L Fiber Services Inc. Support de filtration et passage de filtration
US6745469B1 (en) 1998-05-29 2004-06-08 J&L Fiber Services, Inc. Method of making screen media and a screening passage therefore
EP2290160A1 (fr) * 2007-04-30 2011-03-02 Voith Patent GmbH Procédé de fabrication d'un crible, notamment d'un crible rigide pour le traitement de suspensions de matière fibreuse appropriées à la production de papier
WO2008131974A1 (fr) * 2007-04-30 2008-11-06 Voith Patent Gmbh Procédé de fabrication d'un classeur, en particulier d'un classeur rigide pour le traitement de suspensions de matières fibreuses convenant à la fabrication du papier
WO2008131976A1 (fr) * 2007-04-30 2008-11-06 Voith Patent Gmbh Tamis
US8123912B2 (en) 2007-04-30 2012-02-28 Voith Patent Gmbh Screen
US8216428B2 (en) 2007-04-30 2012-07-10 Voith Patent Gmbh Screen
DE102008059709A1 (de) 2008-11-29 2010-06-02 Voith Patent Gmbh Herstellung eines Siebes, insbesondere eines starren Siebes sowie Sieb, hergestellt nach einem derartigen Verfahren
CN101974864A (zh) * 2010-11-10 2011-02-16 天津市恒脉机电科技有限公司 一种螺旋挤浆机的筛网和包含该筛网的螺旋挤浆机
WO2012079917A3 (fr) * 2010-12-16 2013-02-14 Voith Patent Gmbh Tamis
CN103370470A (zh) * 2010-12-16 2013-10-23 沃依特专利有限责任公司 滤网
CN103370470B (zh) * 2010-12-16 2016-03-09 沃依特专利有限责任公司 滤网
CN114146478A (zh) * 2021-11-03 2022-03-08 宁波市自来水有限公司 一种原水管道用垃圾过滤筒
CN114146478B (zh) * 2021-11-03 2023-02-28 宁波市自来水有限公司 一种原水管道用垃圾过滤筒

Also Published As

Publication number Publication date
FI945073L (fi) 1995-04-29
CA2132921A1 (fr) 1995-04-29
BR9404222A (pt) 1995-06-27
JPH07189158A (ja) 1995-07-25
FI945073A0 (fi) 1994-10-27
KR950011762A (ko) 1995-05-16

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