US3847731A - Twin wire paper making method in which controlled dewatering in tapering gap causes suspension to move at speed of wires - Google Patents

Twin wire paper making method in which controlled dewatering in tapering gap causes suspension to move at speed of wires Download PDF

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Publication number
US3847731A
US3847731A US00198304A US19830471A US3847731A US 3847731 A US3847731 A US 3847731A US 00198304 A US00198304 A US 00198304A US 19830471 A US19830471 A US 19830471A US 3847731 A US3847731 A US 3847731A
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suspension
wires
gap
liquid
wire
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H Arledter
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    • 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
    • D21F1/48—Suction apparatus
    • D21F1/52—Suction boxes without rolls
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type

Definitions

  • ABSTRACT Paper making method in which turbulent suspension under pressure is introduced to a tapering gap between a pair of traveling wires at the speed of the wires, and is dewatered therein by suction applied in a series of zones along the wires in such controlled manner that the quantity of liquid in the suspension decreases from zone-to-zone proportionally to gap width, and the suspension is caused to move through the gap at essentially the speed of the wires and without being subjected to substantial mechanical pressing by the wires.
  • the invention relates to a paper making method employing a machine with two wires joining into a double wire area and confining in front of said area a narrow converging gap for sheet forming.
  • Such machines are known.
  • Suchmachines have the disadvantage that the formed sheet is composed of layers with fibres orientated in the plane of said layers. With increasing wire speed and decreasing consistency of the suspension the layers get more distinct. The single layers are badly connected to each other. Besides, most of the fibres in the layers'are orientated in the direction of wire travel, resulting in different strengths of the sheet in longitudinal and lateral direction.
  • Paper making method in which turbulent suspension under pressure is introduced to a tapering gap between a pair of traveling wires at the speedof the wires, and is dewatered therein by suction applied in a series of zones along the wires in such controlled manner that the quantity of liquid in the suspension decreases from zone-to-zone proportionally to gap width, and the suspension is caused to move through the gap at essentially the speed of the wires and without being subjected to substantial mechanical pressing by the wires.
  • the purpose of the invention is to provide a paper making method in which the machine delivers in a wet process a sheet having a fibre orientation distributed on all dimensional directions equally, and which can utilize high wire speeds.
  • Atleast and preferably more than 50%, of web formation takes place in the converging gap, and the suspension is fed to the gap in a turbulent condition and under a pressure which causes it to enter at the speed of the wires.
  • the suspension is dewatered by suction applied in a series of zones positioned along the path of travel of each wire, and the degree of suction dewatering in each zone is set so that the quantity of liquid in the suspension decreases from zone-to-zone in the direction of wire travel proportionally to the width of the gap.
  • the fibres coming in a turbulent suspension into the gap maintain their orientation in all dimensional directions even during depositing on the wires. Good sheet quality is especially achieved if thequantities of liquid to be sucked away in the zones, and/or the width of the gap is so adjusted that the suspension has reached the frozen condition at the outlet of the gap. Under frozen condition is understood the condition wherein the fibres cannot change their orientation because of the.
  • each dewatering zone preferably has a length, measured in thedirection of wire travel, of 60 to mm, and is provided with a wire supporting surface having a radius of curvature of l,000mm to infinite. These zones are equipped with separate devices foradjusting the quantities of liquid to besucked. away. It is of great advantage-if the dewatering ele ments are stationary suction boxes having perforated wire supporting wallswhich are convex domed against the wires. Manufacturing costs are reduced if the surface of the convex domed wall has the form of a cylin-.
  • the width of the inlet and- /or outlet of the gap is adjustable.
  • the radius of curvature of the dewatering elements can be adjustable.
  • the dewatering elements can be made of links turnable against each other, or can be.
  • Deposition of the fibres on the wires can be advantageously influenced, while maintaining equal speeds for suspension and wires, by hav-ing the quantity of liquid to be sucked away at one side of the gap bigger than, .at the other side of the gap, and then the quantity of liquid at the other side of the gap bigger than at the one side of the gap, alternating in directionof wire travel.
  • the result is a suspension flowing in the form of a serpentine through the gap.
  • Orientation of the fibres in the suspension can also be influenced by adjusting the quantities of liquid to be sucked away so as to have for one orsome zones a certain speed difference between suspension and wires. Neglecting this, that is taken essentially, the suspension is kept at the same speed as the wires.
  • FIG. 1 shows a vertical section, in the direction of wire travel, through a paper making machine
  • FIG. 2 a corresponding vertical section through part of another embodiment
  • FIGS. 3 and 4 show each one form of a gap and dimensioning data for further gaps.
  • the paper making machine shown in FIG. 1 has two wires 1 and 2 which join into a double wire area 3.
  • the wires 1, 2 In front of the double wire area 3, .immediatly before the. wires 1, 2join into area 3 the wires 1, 2 form a converging gap 4 between themselves.
  • the length of the gap 4 is 300 to 2,000 mm.
  • the width of the gap 4 is at the inlet 4 of the gap 6 to 100 mm, and the width of the gap is at its outlet 4 some tenth of millimeter to 5 mm.
  • the wires 1 and 2 travel over dewatering elements 5 and 6, respectively, arranged on both sides of the gap 4.
  • the dewatering elements are subdivided into a plurality of zones, i.e.
  • Each of the zones has an adjusting device-not shownfor adjusting the quantity of the liquid to be sucked away in the respective zone.
  • Dewatering elements 17 and 18, arranged in front of the inlet 4 also each have an adjusting device-mot shown-for adjusting the liquid to be sucked away.
  • the dewatering elements can be moved-by means not shownrelatively to each other so as to make the width of the gap 4 at the inlet 4 or at the outlet 4 bigger or smaller.
  • a chamber 19 for feeding suspension to the gap 4 opens against the inlet 4, i.e. the lower end of gap 4.
  • This chamber 19 has two feeding conduits 20, 21 arranged symmetrically to the gap 4, and a return conduit 22, for the suspension.
  • the inlet width (4) of the gap 4 and the pressure of the suspension to be lead to the gap 4 are so adjustable as to make the speed of the suspension at the inlet 4 equal to the speed of the wires 1, 2.
  • the quantities of liquid to be sucked away with the zones 7 to 16 are so adjustable as to make the speed of the suspension along the gap, i.e. from the inlet 4 to the outlet 4 essentially equal to the speed of the wires 1, 2.
  • the quantities of liquid to be sucked away with the zones and/or the width of the gap 4 are so adjustable as to have reached at least at the outlet 4 of the gap 4 a consistency at which the suspension is in the frozen condition.
  • the dewatering elements 17, 18 at the transition between chamber 19 and inlet 4 are formed as stationary suction boxes with a perforated wire-supporting convex domed wall.
  • turbulence generators i.e. rotatable perforated rollers 23, 24, rotatable bodies 25, 26 and a rotatable cylinder 27.
  • An element of the chamber 19, that is the wall of said chamber can be set under oscillations with periodic frequencies of more than 5 per second, by a vibrator 28.
  • vibrators 29 and 30 serve for oscillating the dewatering elements 5 and 6, respectively with periodic frequencies of more than 50 per second.
  • the direction of oscillating is at an angle of at least degress relatively to the plane of the wires, i.e. as for the vibrator 28 an angle of 30, and for the vibrators 29 and 30 an angle of 90.
  • the suspension has in the chamber 19 practically constant consistency. 1n the gap 4, the consistency increases with short fibre lengths (1 to 6 mm) from 0.1 to 1.5% at the inlet 4 up to 3 to 6% at the outlet 4 With long fibre lengths (6 to 30 mm), the consistency increases from 0.001 to 0.1% at the inlet 4 up to 0.5 to 1% at the outlet 4 Thereby, with the invention, very high wire speeds can be achieved, even with the higher consistencies.
  • the dewatering process can be brought up to 44% consistency, i.e. solids per solids plus liquid, with the help of boxes 31 having perforated wire-supporting convex domed walls, grooved cylinders 32, and a pair of cylinders 33.
  • the gap 4 is arranged vertical and converges in direction of wire travel from below to above.
  • the suspension flows upward in the gap 4.
  • the gap 4 is arranged vertically too, yet the gap converges downwards, and the suspension flows downwards.
  • the chamber for feeding the suspension to the gap 4 is formed as a box 34 the bottom of which is formed by the wires 1 and 2. 1n the box 34, a bath of suspension is maintained. Under the box 34, suction boxes 35 and 36 are arranged. Part of sheet forming takes place on the wires 1, 2 before these wires enter the gap 4. The layer of the sheet lying between the layers formed in box 34 are then formed in gap 4 according to the invention.
  • the quantities of liquid to be sucked away in the zones of the gap 4 are so adjusted as to make the speed of the suspension along the gap essentially equal to the speed of the wires. Maintaining this condition, alternating from zone to zone in the direction of wire travel, firstly, at one side of the gap 4 is sucked away a bigger quantity of liquid than at the other side of the gap 4, then at said other side of the gap is sucked away a bigger quantity of liquid than at the one side of the gap, then in the, in the direction of wire travel, third zone vice versa. That is, the quantity in zone 7 is bigger than in zone 8, in zone 10 bigger than in zone 9, in zone 11 bigger than in zone 12, in zone 14 bigger than in zone 13, in zone 15 bigger than in zone 16.
  • the stream of suspension in gap 4 gets therefore the form of a serpentine.
  • the quantities of liquid to be sucked away in the zones are so adjusted that with a pair of zones, i.e. with the zones 9 and 10, a difference of speeds between suspension and wires occurs.
  • a local acceleration or retardation could be repeated in further pairs of zones.
  • the speed of the suspension can be in general kept equal to the speed of the wires all the same.
  • the ends of the dewatering elements 5 and 6 are staggered relatively to each other at the outlet 4 of gap 4. This is advantageous with small widths of the outlet 4
  • the box 34 more than two feeding and/or return conduits open into it, that is the feeding conduits 37 and 38, and the return conduits 39 and 40.
  • the kind of sheet forming in the box 34 as well as the condition of the suspension delivered to the gap 4 can thereby be influenced.
  • the walls of the dewatering elements 5 and 6 are lightly convex domed against the wires, and have the form of a cylinder section the generatrix of which is an arc of circle with a big radius.
  • the surface of the convex domed wall is made of a material having a coefficient of friction of smaller than 0.1 relatively to a wire made of metal.
  • the sketch at the left side of the drawing shows an inlet width d an outlet width d and a length 1 of the gap.
  • the gap is in the drawing confined by two arcs of circle, each of them reaching from the inlet to the outlet of the gap, and having a radius r and a sector angle a.
  • the gap is subdivided-into twelve zones of equal length.
  • a table gives the portion of the liquid to be sucked away, which is left in the suspension at the end of each zone (in of the total quantity of liquid to be sucked away in the whole gap) for four different forms of gap.
  • the length l of the gaps is equal with all forms, namely 1,200 mm, while the difference d between inlet width d and outlet width d as well as the radius 'r and the corresponding sector angle a are different. 5 by the invention.
  • FIG. 4 corresponds to FIG. 3. Yet, the length 1 of the Table 6 Shows Production capacities for p p made gaps i 500 mm d th gaps are bdi id d i fi of synthetic fibres, dependent on fibre lengths and corzones. There are seven different forms of gaps.
  • the table given quancomblhlhg Tables 2 to 5 Ph can See P- hh f tity of liquid decreases in the direction of wire travel 10 hohs of m of the Speed qhahthy Ofhqhld from zone to zone proportionally to the width of the to be Shcked hl lehgth of the-suction e and gap
  • the diff between the total quantity (100%) productlon capacity are a function of the consistency and the quantity given in the table has to be sucked of the h h' away at the respective zone end.
  • Table 1 shows the respective than the length of thehhres; As Shown thls Cohdl' pressures (meter water column) for some wire speeds hoh can he met whhthe lhvehhoh- (meter per minute). Under paper making machlne and paper is also The width (mm) of the inlet 1 of the gap 4 is a func understood, in the sense of th s specification, a mation of the quantity of suspension (liter per minute and Chlhe Produces a paper'hke Sheet for example meter lateral width of the sheet) flowing through the a machhe for pmdhc'hg hoh'woveh websgap and of the wire speed. For equal'speeds of suspension and wires, Table 2 shows some examples. TABLES:
  • the production of the machine according to the in- 40 88 vention furthermore-depends on the degree of freeness, 600 610 the dewateringor suction area, the weight of square 900 meter of paper, and thedewatering vacuum or suction 2M pressure.
  • Dewatering on the double wire system that is from two sides of the-sheet, and up to consistencies of l to 6% results in big quantities of liquid sucked away.
  • Table 4 the quantities (liter/per minute and Table 2 square meter suction area) are given for some kinds of suspension, dependent on different suction pressures Quantity of Liquid (llmin/m) (meter water column).
  • th uantities of li 'd wi h w h t 10 m 15 0.020 14.0 20.8 t dra n throug he two w1res 1n each zone are unequal; and 10 to 30 0.005 3.5 b. in adjacent zones the greater quantity is withdrawn through different wires, c. whereby the suspension in the gap has a tendency I claim: to form a serpentme.
  • a paper making method in which at at least 30% of the forming of a continuous sheet is effected by dewatering a fiber suspension in a tapered gap defined by 4.
  • a method as defined in claim 1 including the step of continuously circulating suspension through said region between a plurality of feeding and return conduits.
  • a method as defined in claim 1 including the step of vibrating suspension in said region at a frequency greater than 5 cycles per second.
  • a method as defined in claim 1 including the step of vibrating suspension in the gap at a frequency greater than 50 cycles per second.

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US00198304A 1970-11-16 1971-11-12 Twin wire paper making method in which controlled dewatering in tapering gap causes suspension to move at speed of wires Expired - Lifetime US3847731A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT1027370A AT328283B (de) 1970-11-16 1970-11-16 Verfahren und einrichtung zur herstellung vonfaserstoffbahnen mit raumlich ausgerichteten fasern

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US (1) US3847731A (de)
AT (1) AT328283B (de)
CA (1) CA947553A (de)
DE (1) DE2155974A1 (de)
FR (1) FR2117102A5 (de)
GB (1) GB1373249A (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4491521A (en) * 1981-09-29 1985-01-01 Escher Wyss Gmbh Dewatering apparatus
US4532008A (en) * 1983-07-22 1985-07-30 The Black Clawson Company Horizontal twin wire machine
US4648943A (en) * 1984-05-18 1987-03-10 Valmet-Dominion Inc. Vibrating forming shoe in a twin wire former
US4885088A (en) * 1985-12-19 1989-12-05 Maschinenfabrik Andritz Actiengesellschaft Filter belt press
US5201999A (en) * 1991-06-10 1993-04-13 Beloit Technologies, Inc. Twin wire forming apparatus
US20020096297A1 (en) * 2000-03-14 2002-07-25 Alfred Bubik Twin wire former
US20030183355A1 (en) * 2001-03-16 2003-10-02 Franz Petschauer Process and device for removing water from a mechanical pulp, chemical pulp or paper sheet
EP1052082A3 (de) * 1996-08-20 2004-01-07 JFE Steel Corporation Vorrichtung zur Herstellung von faserverstärkten, thermoplastischen Harzplatten
US20060254739A1 (en) * 2003-05-06 2006-11-16 Metso Paper, Inc. Method and apparatus at a twin-wire press

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CS310590A2 (en) * 1989-06-21 1991-12-17 Reinhard Gustav Gmbh Method of water-containing fibrous web dehydratation on paper making machines with longitudinal screen and respective dehydratating unit
DE4014403C2 (de) * 1990-05-04 1994-03-10 Escher Wyss Gmbh Vertikalformer

Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1241905A (en) * 1917-03-26 1917-10-02 Hans C Behr Process of and apparatus for the continuous separation of liquids from solids.
US1645068A (en) * 1922-10-02 1927-10-11 Goodyear Tire & Rubber Machine for making a fiber composition
US1875075A (en) * 1930-01-25 1932-08-30 Masonite Corp Liquid separation
US2046271A (en) * 1935-10-26 1936-06-30 Eastman Kodak Co Controlled leak for paper making machines
GB560577A (en) * 1942-10-17 1944-04-11 Turners Asbestos Cement Co Improvements relating to the manufacture of asbestos-cement and like products
FR1005530A (fr) * 1947-08-01 1952-04-11 Perfectionnements à la fabrication mécanique du papier
US3027940A (en) * 1958-12-31 1962-04-03 Lodding Engineering Corp Adjustable supports for fourdrinier screen wires
US3034577A (en) * 1958-01-23 1962-05-15 Rice Barton Corp Mechanism for removal of air from paper-making machine feed stock
US3103463A (en) * 1961-03-09 1963-09-10 Beloit Iron Works Method and means for dispersing fibrous slurries
US3149028A (en) * 1961-09-26 1964-09-15 Paper Machine Components Inc Paper making machine and process
US3215593A (en) * 1963-01-25 1965-11-02 Black Clawson Co Headbox for twin wire paper making apparatus
US3403073A (en) * 1964-05-20 1968-09-24 Time Inc Paper-forming method and apparatus
US3438854A (en) * 1964-10-29 1969-04-15 Time Inc Dual wire paper forming apparatus and suction box therefor
FR1582914A (de) * 1967-08-02 1969-10-10
US3560334A (en) * 1965-09-27 1971-02-02 Mead Corp Apparatus for incorporating additive dispersions to wet webs of paper
US3578558A (en) * 1968-02-19 1971-05-11 Black Clawson Co Twin wire paper making assembly
US3578561A (en) * 1968-03-08 1971-05-11 Black Clawson Co Paper forming apparatus

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1241905A (en) * 1917-03-26 1917-10-02 Hans C Behr Process of and apparatus for the continuous separation of liquids from solids.
US1645068A (en) * 1922-10-02 1927-10-11 Goodyear Tire & Rubber Machine for making a fiber composition
US1875075A (en) * 1930-01-25 1932-08-30 Masonite Corp Liquid separation
US2046271A (en) * 1935-10-26 1936-06-30 Eastman Kodak Co Controlled leak for paper making machines
GB560577A (en) * 1942-10-17 1944-04-11 Turners Asbestos Cement Co Improvements relating to the manufacture of asbestos-cement and like products
FR1005530A (fr) * 1947-08-01 1952-04-11 Perfectionnements à la fabrication mécanique du papier
US3034577A (en) * 1958-01-23 1962-05-15 Rice Barton Corp Mechanism for removal of air from paper-making machine feed stock
US3027940A (en) * 1958-12-31 1962-04-03 Lodding Engineering Corp Adjustable supports for fourdrinier screen wires
US3103463A (en) * 1961-03-09 1963-09-10 Beloit Iron Works Method and means for dispersing fibrous slurries
US3149028A (en) * 1961-09-26 1964-09-15 Paper Machine Components Inc Paper making machine and process
US3215593A (en) * 1963-01-25 1965-11-02 Black Clawson Co Headbox for twin wire paper making apparatus
US3403073A (en) * 1964-05-20 1968-09-24 Time Inc Paper-forming method and apparatus
US3438854A (en) * 1964-10-29 1969-04-15 Time Inc Dual wire paper forming apparatus and suction box therefor
US3560334A (en) * 1965-09-27 1971-02-02 Mead Corp Apparatus for incorporating additive dispersions to wet webs of paper
FR1582914A (de) * 1967-08-02 1969-10-10
US3578558A (en) * 1968-02-19 1971-05-11 Black Clawson Co Twin wire paper making assembly
US3578561A (en) * 1968-03-08 1971-05-11 Black Clawson Co Paper forming apparatus

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4491521A (en) * 1981-09-29 1985-01-01 Escher Wyss Gmbh Dewatering apparatus
US4532008A (en) * 1983-07-22 1985-07-30 The Black Clawson Company Horizontal twin wire machine
US4648943A (en) * 1984-05-18 1987-03-10 Valmet-Dominion Inc. Vibrating forming shoe in a twin wire former
US4885088A (en) * 1985-12-19 1989-12-05 Maschinenfabrik Andritz Actiengesellschaft Filter belt press
US5201999A (en) * 1991-06-10 1993-04-13 Beloit Technologies, Inc. Twin wire forming apparatus
EP1052082A3 (de) * 1996-08-20 2004-01-07 JFE Steel Corporation Vorrichtung zur Herstellung von faserverstärkten, thermoplastischen Harzplatten
US20020096297A1 (en) * 2000-03-14 2002-07-25 Alfred Bubik Twin wire former
US6521091B2 (en) * 2000-03-14 2003-02-18 Voith Paper Patent Gmbh Twin wire former
US20030183355A1 (en) * 2001-03-16 2003-10-02 Franz Petschauer Process and device for removing water from a mechanical pulp, chemical pulp or paper sheet
US7090746B2 (en) * 2001-03-16 2006-08-15 Andritz Ag Process and device for removing water from a mechanical pulp, chemical pulp or paper sheet
US20060254739A1 (en) * 2003-05-06 2006-11-16 Metso Paper, Inc. Method and apparatus at a twin-wire press
US7476292B2 (en) * 2003-05-06 2009-01-13 Metso Paper, Inc. Method and apparatus for use with a twin-wire press

Also Published As

Publication number Publication date
ATA1027370A (de) 1975-05-15
AT328283B (de) 1976-03-10
CA947553A (en) 1974-05-21
GB1373249A (en) 1974-11-06
DE2155974A1 (de) 1972-05-25
FR2117102A5 (de) 1972-07-21

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