EP0410556A2 - Couverture pour boîte d'aspiration - Google Patents

Couverture pour boîte d'aspiration Download PDF

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Publication number
EP0410556A2
EP0410556A2 EP90301274A EP90301274A EP0410556A2 EP 0410556 A2 EP0410556 A2 EP 0410556A2 EP 90301274 A EP90301274 A EP 90301274A EP 90301274 A EP90301274 A EP 90301274A EP 0410556 A2 EP0410556 A2 EP 0410556A2
Authority
EP
European Patent Office
Prior art keywords
fabric
suction box
slot
cover
movement
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Withdrawn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
EP90301274A
Other languages
German (de)
English (en)
Other versions
EP0410556A3 (en
Inventor
Paul F. Hood
Klaus M. Essele
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.)
Albany International Corp
Original Assignee
Albany International Corp
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 Albany International Corp filed Critical Albany International Corp
Publication of EP0410556A2 publication Critical patent/EP0410556A2/fr
Publication of EP0410556A3 publication Critical patent/EP0410556A3/en
Withdrawn legal-status Critical Current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
    • D21F3/00—Press section of machines for making continuous webs of paper
    • 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

  • This invention pertains to an improved cover for a suction box for use, for example, in machines such as papermaking and boardmaking machines and the like, wherein water is removed from a moving fabric or web by suction.
  • Various types of paper may be made at high speed and economically on so-called papermaking machines.
  • a slurry of wood pulp and other materials is dispensed onto an endless forming fabric.
  • the forming fabric with the slurry moves across several suction boxes used to remove water from the slurry to form a continuous paper sheet. Since this sheet still has a high water content, it is then transferred to a press section where it is contacted with at least one continuous press fabric and fed through press nips for the further removal of water by mechanical means.
  • the press fabric is then passed over another suction box where water is removed from the press fabric.
  • the press fabric is made of materials which may be woven and manufactured to form a continuous fabric, or which may have two opposite ends joined by a seam.
  • the suction boxes are normally provided with a cover having a straight slot extending transversely across the width of the press fabric.
  • the slot size ranges from 3/8 ⁇ to 3 ⁇ (1 to 7.5 cm) in linear length.
  • the suction box is described herein as part of the press section of a papermaking machine; however it should be understood that it may also be used in the paper forming section).
  • This type of suction box has been found to be unsatisfactory for a number of reasons. For example, if a press fabric with a seam is used, as the seam goes over the slot, the fabric makes a loud, unpleasant popping sound which is not only irritating, but also increases the overall noise level produced by the machine.
  • the seam also rubs against the slot edges causing the seam flap, formed of batt material, to wear out before the rest of the fabric.
  • the fabric may also fail due to the flexing of the fabric caused by the edges of the slot.
  • suction box cover is also used in which slots are made in a so-called herringbone pattern. These slots are usually defined by at least four contact edges. This type of cover has also been unsatisfactory because studies have shown that if the number of edges traversed by a fabric is increased, the wear and tear of the fabric also increases. This wear and tear is even more pronounced with fabrics having seams because the seam flap wears away faster as explained above.
  • Another disadvantage is that the open area (length X width) of the herringbone box cover usually is greater than a single straight slot. This reduces both the specific air flow (volume/area) and vacuum level, thus reducing the system's capability to properly dewater the press fabric. To overcome this problem a larger vacuum source may be necessary, requiring both capital expenditure and increased operating costs.
  • the present invention is also concerned with the problem of providing an improved box cover at which the flexing of the fabric at the slot is reduced or eliminated.
  • the invention is concerned with the problems of reducing or eliminating the sound produced during use compared with the sound produced by prior art box covers, and providing a suction box cover in which the number of edges traversed by the press fabric is reduced.
  • the invention provides a suction box for extracting water from a fabric continuously moving in a papermaking machine, comprising a body for connection to a vacuum source, and a cover secured to said body and having an elongated slot in communication with said body, said slot extending in a direction substantially transversal to the direction of movement of the fabric, characterised in that the said slot comprises a plurality of slot segments forming a zig-zag pattern.
  • the cover is secured to the body and is constructed and arranged to support a papermaking fabric, for example, a press fabric moving continuously across it.
  • each slot segment is substantially straight.
  • each slot segment is inclined at the same angle to the direction of movement of the fabric, the angle preferably being about 45°.
  • the effective area of the slot is substantially equal to the area of a transversal slot of the prior art and further, that the slot extends substantially across the width of the fabric (i.e. in the cross-machine direction).
  • the slot segments are joined end to end to form a continuous zig-zag pattern across the width of the fabric.
  • the invention also provides a suction box for extracting water from a fabric moving in a papermaking or boardmaking machine, the suction box having a cover provided with a plurality of slot segments that each extend in a direction inclined at an acute angle to the direction of movement of the fabric, characterised in that the arrangement of the slot segments is such that as the fabric, in use, passes over the cover, at least most of the width of the fabric passes over two slot segment edges.
  • the slot segments together extend in a direction substantially transverse to the direction of movement of the fabric and the slot segments may be joined so as to form a single slot. It is preferred that the open area defined by the slot segment edges is about 1 square inch of area per inch (2.5 cm2/cm) of machine width in the direction perpendicular to the direction of movement of the fabric.
  • the invention also provides a cover for a suction box as described above and a papermaking or boardmaking machine including such a suction box.
  • the invention provides a process for extracting water from a fabric moving in a papermaking or boardmaking machine, using a suction box as described above.
  • the overall wear of the fabric is reduced and, if a seam flap is present, the noise produced therefrom and resultant wear is also substantially reduced.
  • the open area per inch of width is as specified above so that traditional vacuum levels may be used to dewater the fabric properly.
  • a suction box 10 constructed in accordance with this invention includes a main body 12 which is connected to a vacuum source that provides suction (not shown) by a connecting pipe 14.
  • the box is provided with a cover 16 which is secured to the main body in a known manner.
  • the cover 16 is secured to the main body in a dovetail joint, however other types of connections are equally suitable.
  • the cover is provided with a single slot 18.
  • the slot 18 is composed of a plurality of substantially straight slot segments, such as 18′ and 18 ⁇ , each segment being disposed at an angle of about 45 degrees with respect to the machine direction indicated by arrow 20.
  • the segments are joined end to end, with each two adjacent segments being perpendicular to each other to form a continuous zig-zag pattern as shown in Figure 2.
  • Each segment may be for example about 5 inches (12.5 cm) long.
  • the suction box is disposed in a paper machine, such as for example its press section, along the continuous path of a press fabric 22.
  • the press fabric 22 traverses the cover in a continuous movement indicated by the arrow 20.
  • the vacuum in suction box 10 extracts water from the fabric through slot 18.
  • a fabric 22 traversing the box cover overlaps only a small number of relatively narrow slot sections of the slot.
  • the section of fabric traversing an imaginary line 24 overlaps sections of five slot segments. Between these segments the fabric is fully supported by the box cover so that the fabric does not travel over any edges transversal to its movement.
  • any fabric area along line A-B must pass over four edges or slot edges as it moves over the conventional herringbone box cover.
  • any fabric area moving along such a line would only pass over two slot edges, substantially reducing wear.
  • the cover is moulded from a high impact plastic material with a low coefficient of friction such as polyethylene, although other materials such as silicone nitride and ceramics can be used.
  • a high impact plastic material with a low coefficient of friction such as polyethylene, although other materials such as silicone nitride and ceramics can be used.

Landscapes

  • Paper (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
  • Treatment Of Fiber Materials (AREA)
EP19900301274 1989-07-27 1990-02-07 Suction box cover Withdrawn EP0410556A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US38571989A 1989-07-27 1989-07-27
US385719 1989-07-27

Publications (2)

Publication Number Publication Date
EP0410556A2 true EP0410556A2 (fr) 1991-01-30
EP0410556A3 EP0410556A3 (en) 1991-09-04

Family

ID=23522587

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900301274 Withdrawn EP0410556A3 (en) 1989-07-27 1990-02-07 Suction box cover

Country Status (9)

Country Link
EP (1) EP0410556A3 (fr)
JP (1) JPH0359188A (fr)
KR (1) KR910003218A (fr)
AU (1) AU4978290A (fr)
BR (1) BR8906840A (fr)
CA (1) CA2008577A1 (fr)
FI (1) FI895467A0 (fr)
NO (1) NO894774L (fr)
ZA (1) ZA898947B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7540943B2 (en) 2003-11-17 2009-06-02 Astenjohnson, Inc. Shaped slot vacuum dewatering box cover
CN103114487A (zh) * 2013-03-08 2013-05-22 李国章 尼龙吸水箱面板

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2957522A (en) * 1958-01-30 1960-10-25 Thomas L Gatke Suction box cover
US3598694A (en) * 1969-08-15 1971-08-10 Philip Wiebe Mechanical pulsating forming board
DE2163330A1 (de) * 1971-12-21 1973-06-28 Rauchmaul Kunststoffverarbeitu Siebsaugkasten
FR2349678A1 (fr) * 1976-04-28 1977-11-25 Walker Charles Cons Ltd Articles composes
FR2637622A1 (fr) * 1988-10-06 1990-04-13 Bartelmuss Heinrich Ing Revetement

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2957522A (en) * 1958-01-30 1960-10-25 Thomas L Gatke Suction box cover
US3598694A (en) * 1969-08-15 1971-08-10 Philip Wiebe Mechanical pulsating forming board
DE2163330A1 (de) * 1971-12-21 1973-06-28 Rauchmaul Kunststoffverarbeitu Siebsaugkasten
FR2349678A1 (fr) * 1976-04-28 1977-11-25 Walker Charles Cons Ltd Articles composes
FR2637622A1 (fr) * 1988-10-06 1990-04-13 Bartelmuss Heinrich Ing Revetement

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7540943B2 (en) 2003-11-17 2009-06-02 Astenjohnson, Inc. Shaped slot vacuum dewatering box cover
CN103114487A (zh) * 2013-03-08 2013-05-22 李国章 尼龙吸水箱面板

Also Published As

Publication number Publication date
BR8906840A (pt) 1991-05-07
AU4978290A (en) 1991-01-31
JPH0359188A (ja) 1991-03-14
CA2008577A1 (fr) 1991-01-27
NO894774L (no) 1991-01-28
EP0410556A3 (en) 1991-09-04
FI895467A0 (fi) 1989-11-16
NO894774D0 (no) 1989-11-29
ZA898947B (en) 1990-08-29
KR910003218A (ko) 1991-02-27

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