US3234079A - Papermaking machine having a polyethylene suction box top - Google Patents

Papermaking machine having a polyethylene suction box top Download PDF

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Publication number
US3234079A
US3234079A US256059A US25605963A US3234079A US 3234079 A US3234079 A US 3234079A US 256059 A US256059 A US 256059A US 25605963 A US25605963 A US 25605963A US 3234079 A US3234079 A US 3234079A
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United States
Prior art keywords
wire
tops
machine
suction box
polyethylene
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Expired - Lifetime
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US256059A
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English (en)
Inventor
Poeschl Rudolf
Poeschl Wilhelm
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Individual
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Individual
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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
    • D21F1/523—Covers thereof

Definitions

  • Suchsuction box tops consist of plastic plates on a backing consisting, e.g., of Wood or metal.
  • This twolayer material has the disadvantage that the walls of the holes in the suction box tops are uneven, particularly at the joint between the two layers, and these uneven portions promote an accumulation of sucked-off fiber material on the Walls of the holes so that the holes in the suction box tops 'are gradually reduced in cross section. For this reason, such suction box tops must be frequently cleaned, which results again in'a shutdown and reduction in output.
  • the invention resides in a machine for treating paper or pulp, a machine wire for receiving the material to be treated, means, such as at least one suction box and/or at least one forming board for extracting water from the material to be treated, said means having sliding surfaces on'their tops, on which the machine wire slides, said tops consisting of a polyethylone plastic softer than the material of the wire, whereby the coeificient of friction between the machine Wire and the tops is less than 0.12, so that the speed of the wire is increased by a reduction of the slip of the wet wire driving roller and whereby the tops made only from this plastic are stable in shape and self-supporting and have an active water-extracting area of at least 40% of the waterextracting zone to increase the extraction of water from the stock.
  • the materials used according to the invention for the suction box and/ or forming board tops are stable up to temperatures above C. This affords the advantage that the stock can be applied in boiling condition without damage to the forming board and/or suction box tops.
  • the application of the stock in boiling condition has become increasingly popular in recent years.
  • sintered low-pressure polyethylene having a molecular weight of about 1,000,000 is used as a plastic.
  • This material has a particularly high impact strength so that forming board and/ or suction box tops made from this material can be surfaced by surfacing machines having surfacing knives rotating at high speed. It has been found suitabe to charge this material as a powder into an elongated mold and to sinter it there under a high pressure and at "an appropriate temperature.
  • Plates of any desired size which are made from such material have a particularly low coefficient of friction with respect to the wire so that the coefiicient of friction between the wire, on the one hand, and the forming board and/or suction box tops, on the other hand, may be reduced below 0.1, in accordance with the invention.
  • These admixtures may be added. in the form of powders and may consist of molybdenum sulfide powder or molybdenum disulfide powder, on the one hand, and graphite powder, on the other hand.
  • the electrically conducting admixtures impart to, the suction .box and/or forming board top such a conductivity that the electrostatic the resistance to acid, the stability of shape, the resistance to swelling, low wear and temperature stability etc; In stead of molybdenum sulfide or molybdenum disulfidegon the .one. hand, and graphite'powder, on the other hand, other substances which reduce friction and/or impart electrical conductivity may be added to the PIZIS-r' tic.
  • the plastic material may contain about i /2 percent by weight of molybdenum sulfide powder or molybdenum disulfide powder and about /2 percent by weight-of graphite powder.
  • the particle sizes of theadmixture will depend on the nature of the plastic material to .be processed and on;
  • the particle size of the admixtures may be between 5 microns and 0.05 micron, preferably in the range between 2 microns and 0.2 micron;
  • the particle size of the admixtures may be between 5 microns and 0.05 micron, preferably in the range between 2 microns and 0.2 micron;
  • the .scope of the invention it is also possible within the .scope of the invention tomake the suction box and/or forming board tops in one piece in order to avoid vacuum defects which would interrupt the operation. This is of special importance because, even very small disturbances in the charging and distribution of .thestockon the wire will result in undesirable effects in the finishedroll. If the paper does not summation of micro defects; For this reason it-is highly desirable that the suction box and/ or forming board tops l 4 have a uniform thickness throughout, the roll cannot be cylindrically wound but will have thumps due to a repeated should be maintained as truly planar as possible in order to avoid. animpression of'uneven portions into .the stock.
  • tops can best be maintained if they are-made in one piece
  • ing board top which. cooperates with the .wireis polished, preferably to :a high finish.-.
  • extremely low coeflicients of friction may easily begobtained; these values may be less than 0.095 or even less than 0.09.
  • plastics which may be usedaccording to the invention include extruded polypropylene and extruded polyester and polyether products, providedthat they have properties similarto those of polyethylene.
  • Example 1 A suction box top 4000'millimeters long and 350 wide isto be made and to be-providedwithholes in'a zone having a length of 3000mm. and a width of 280 P mm. The holes are arranged so that relatively wide landsi remain between the .suction holes .of the top.
  • parts of :a non apertured. plate of polyethylene are made: byinjection molding and are then drilled in screwsso that the fastener lies in the: lowermost 10 mm, which is the limit-towhichthe top can bemachined, for
  • these parts can be surfaced with any milling,planing or other surfacing machine.
  • present invention con- It.-is also. of special .im-.
  • the polishing of the holes 1 5 The activeiwaterv extracting area of this plate is 60% of the zjone fornied with holes. This requires the provision of holes of 12 mm. and the lands remaining between the holes are only 3.5 mm wide.
  • polyethylene or sintered low-pressure polyethylene having a low molecular weight about 2 0(:),0 and. a particul arly low coe ilicient of friction will be used.
  • suction 'holes polished to a high finish are also to be used, the use of sintered low-pressure polyethylene having a high molecular weight (about. 1,000,000) is recommended. This material will not take up water and will resist the impacts occurring during mac hining.
  • the chemical stability of thematrial. will a ur that heh h finish w be Preserved during operation even if boiling stock is charged.
  • Example 3 Suction box strips for use with suction boxes having a strip top are to be made. Th'ese suction box strips may be made, e.g., from non-apertured suction box top plates by cutting them to suitable lehgth. If the strip has an overall thickness of, e.g., 30 him, it may be connected to the suction box by screws disposed in the lowermost 10 mm. I v
  • a machine wire 1 runs around a breast roll 2 and a lower couch roll 3.
  • the lower couch roll 3 is driven by an electric motor 4 and forms the driving member for the wire 1.
  • the breast roll 2 is a reversing roll, which is not driven.
  • the direction of rotation of the lower couch roll 3 is indicated by arrow 5 and the direction of movement of the wire 1 is indicated by arrow 6.
  • the stock consisting of fiber pulp is charged from a hopper 7 onto the wire 1.
  • the wire runs over a forming board 8, which is closed at its top by an apertured top 9.
  • the forming board 8 is formed by a trough, into which a large portion of the liquid is drained out of the stock through the apertured top 9. From the latter, the wire 1 moves over a plurality of wire guide rolls 10, which cause further liquid to drain through the wire.
  • the liquid flows from the wire guide rolls 10 into a trough 11 which constitutes at the same time a frame of the machine.
  • suction boxes 12 are arranged, which are closed at the top by suction box tops 13, over which the wire 1 moves.
  • the suction box tops 13 have the same design as the top 9 and in FIG. 2 it will be seen that length l of the suction box top 13 corresponds to the width of the machine.
  • These suction box tops 13 are in one piece and their longitudinal edge 14 extends transversely to the direction of movement of the wire 1 as shown by the arrow 6.
  • the suction boxes have the form of hollow troughs and are connected by conduits 15 to a vacuum pump 16, by which a vacuum is produced in the suction boxes 12.
  • the suction box tops 13 are formed with holes 17, over which the liquid is sucked out of the stock through the wire 1.
  • the wire 1 runs over a deflecting roll 18 to the lower couch roll 3.
  • 19 is the upper couch roll, which is not driven and serves only to press the wire and the web of stock 20 lying on the wire.
  • the web of stock 20 is removed and passed onto the dryer felt, which is not shown.
  • the returning lower course of the wire is designated at1.
  • This returning course 1' moves overstationary guide rolls 2'1, 22 and vertically adjustable rolls 23 back to the breast roll 2.
  • 24 is a dancer roll.
  • the machine wife 1 is endless and the tension of the wire is adjusted by the vertically adjustable rolls 23' and the dancer roll 24
  • the lowering of the vertically adjustable rolls 23 will increase thete'nsion of the wire.
  • These vertically adjustable rolls 23 can be adjusted in accordance with the length of the wire.
  • the dancer roll 24 is pivotally movable about a shaft 25 and is urged by gravity onto the wire 1 to effect anautomatie adjustment of the tension of the wire.
  • the tension of the wire 1 must be so high that the lower couch roll 3 i's capable of driving the wire.
  • FIG. 3 is a topplan viewjshowin'g a portion of the suction box top 13. It serves to define the expression active water extracting area.
  • a rectangle having sides a and b is shown in dotted lihes and is assumed to have an area Y.
  • the cross-sectional areas. of the circular holes in the rectangle 11, 12 is assumedto be X.
  • the active water extracting area equals the quotient X Y
  • This active zone water extracting suction area is at least 40% of the waterextracting 'zone.
  • the circular holes 17 may be replaced by elongated holes extending transversely to the direction of movement of the wire.
  • FI G 4 is a top vplan view showing a suction box top 13 which is formed 'by'spaced apart strips 26 which extend transversely to the direction of movement 6 of the wire 1. Inserts 28 are provided. between the strips 26 at the'edges 27 of the top 13. The spaces 29 between the strips 26 form the suction holes.
  • a machine for treating paper or pulp a machine wire for receiving the material to be treated, a wire driving roller and means coop'erable with the Wire for extractingwater frointh'e material to be treated, said means having'top's provided with sliding surfaces on which the machine wire slides, said tops being composed substantially of a polyethylene-plastic softer than the material of the wire, the coefiicient of friction between the machine wire and the tops being less than 0.12 so that the speed of the wire is increased, the tops formed only from this plastic being stable in shape and of sufiicient thickness to be self-supporting and have an active water extracting area of at least 40% of the water extracting zone to increase the extraction of water from the stock.
  • polyethylene-plastic is sintered low-pressure polyethylene having a molecular weight of about 1,000,000.
  • the polyethylene-plastic contains admixtures for reducing friction and admixtures which are electrically conducting for dissipating eletrostatic charges.
  • polyethylene-plastic contains the admixtures of the group consisting of molybdenum sulfide powder or molybdenum disulfide powder in an amount up to 3 percent by weight for reducing friction.
  • polyethylene plastic contains admixtures consisting of graphite powder in an amount up to 3 percent by Weight for dissipating electrostatic charges.
  • the polyethylene-plastic contains admixtures of the group consisting of molybdenum sulfide powder or molybdenum di-1 sulfide powder and graphite powder and in an amount up to 3 percent by weight'for reducing friction and dissipating electrostatic charges, respectively.
  • plastic material contains about /2 percent by weight of molybdenum sulfide powder or molybdenum disulfide powder and about /2 percent by weight of graphite powder.
  • the polyethylene-plastic contains admixtures for reducing friction with the particle sizes of the admixtures being be-- tween 5 microns and 0.2 micron.
  • the polyethylene-plastic contains admixtures which are electrically conducting for dissipating electrostatic charges with the particle sizes of the admixtures being between 5 microns and 0.2 micron.
  • tion and admixtures which are electrically conducting for dissipating electrostatic charges with the particle sizes of the admixtures being between 5 microns and 0.2 micron.
  • polyethylene-plastic contains admixtures which are electrically conducting for dissipating electrostatic charges with the particles sizes of the admixtures being between 2 microns and 0.5 micron.
  • active water extracting area is about of the water extracting zone.

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US256059A 1962-02-07 1963-02-04 Papermaking machine having a polyethylene suction box top Expired - Lifetime US3234079A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT99662A AT248853B (de) 1962-02-07 1962-02-07 Sauger- oder Siebtischplatte bzw. -leiste für Papier- oder Zellstoffentwässerungsmaschinen

Publications (1)

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US3234079A true US3234079A (en) 1966-02-08

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US256059A Expired - Lifetime US3234079A (en) 1962-02-07 1963-02-04 Papermaking machine having a polyethylene suction box top

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AT (1) AT248853B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009068728A1 (en) * 2007-11-28 2009-06-04 Metso Paper, Inc. Forming section

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2246092A (en) * 1940-07-26 1941-06-17 Du Pont Bearing
US2246086A (en) * 1940-01-08 1941-06-17 Du Pont Bearing
US2600321A (en) * 1949-12-29 1952-06-10 Gen Electric Self-lubricated plastics
US2695425A (en) * 1952-02-23 1954-11-30 Polymer Corp Method of making sintered nylon articles and resultant product
US2893486A (en) * 1956-02-27 1959-07-07 Crown Zellerbach Corp Fourdrinier paper making machine
US2951053A (en) * 1955-02-17 1960-08-30 Mobay Chemical Corp Elastic polyurethane composition and method for making same
CA619673A (en) * 1961-05-09 Proulx Jean Suction box cover

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA619673A (en) * 1961-05-09 Proulx Jean Suction box cover
US2246086A (en) * 1940-01-08 1941-06-17 Du Pont Bearing
US2246092A (en) * 1940-07-26 1941-06-17 Du Pont Bearing
US2600321A (en) * 1949-12-29 1952-06-10 Gen Electric Self-lubricated plastics
US2695425A (en) * 1952-02-23 1954-11-30 Polymer Corp Method of making sintered nylon articles and resultant product
US2951053A (en) * 1955-02-17 1960-08-30 Mobay Chemical Corp Elastic polyurethane composition and method for making same
US2893486A (en) * 1956-02-27 1959-07-07 Crown Zellerbach Corp Fourdrinier paper making machine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009068728A1 (en) * 2007-11-28 2009-06-04 Metso Paper, Inc. Forming section
EP2212471A4 (de) * 2007-11-28 2014-08-06 Valmet Technologies Inc Formbereich

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Publication number Publication date
AT248853B (de) 1966-08-25

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