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
  • D21F1/0036—Multi-layer screen-cloths
  • D21F1/0045—Triple layer fabrics
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S162/00—Paper making and fiber liberation
  • Y10S162/90—Papermaking press felts
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S162/00—Paper making and fiber liberation
  • Y10S162/903—Paper forming member, e.g. fourdrinier, sheet forming member

Definitions

• the invention relates to a paper machine screen, consisting of at least one individual fabric for the paper side and at least one individual fabric for the running side, each consisting of a set of weft threads and warp threads, at least some of the individual fabrics arranged one above the other being connected to one another via binding threads.
• the sheet forming unit is usually designed as a twin wire former, in many cases also as a gap former. It is characteristic of the machines that the sheet formation process takes place immediately between two paper machine screens in a relatively short dewatering zone. This short distance and the high production speed reduce the time for sheet formation to a few milliseconds. During this period, the solids content or dry content of the fiber suspension must be increased from approximately 1% to approximately 20%. For paper machine screens, this means that they must have a very high drainage capacity, but still no marking allowance to be left in the paper and offer high fiber support.
• top wefts are replaced by pairs of binding structural threads.
• the ratio of real top wefts by weft or warp threads to the pairs of binding wefts can vary.
• PCT publications WO 99/06630 and WO 99/06632 are such Known fabrics in which the upper fabric is realized in the manner of a plain weave by the combination of two binding weft threads. In these known solutions, the lower fabric is again in the form of a five-shaft weave.
• the object of the invention is to help avoid the disadvantages described in the prior art, in particular to create a paper machine screen which is distinguished by high strength values, in particular has a high degree of transverse stability and at the same time has comparable drainage capacities offers how to avoid the known solutions as well as the formation of marks in the paper.
• a paper machine screen with the features of claim 1 in its entirety.
• the respective binding thread on the paper side overlaps warp threads of the individual fabric at defined points, which are underpinned on their opposite side by at least one weft thread of this individual fabric, the connection of the two fabric layers (paper side and running side ) again realized by binding threads, which, however, then fully integrate into the fabric structure of the paper side and thereby support the binding point produced in each case by the special type of connection, so that the binding threads thus remain on one level with the wefts and the remaining warp threads.
• a high-strength paper machine sieve is achieved, with very good drainage performance and a uniform structure, especially on the paper side, so that the undesired markings in the paper are avoided.
• top weft threads at the points where they are drawn through the binding thread into the interior of the fabric are supported from below by the associated weft thread of the individual fabric on the paper side.
• the functional separation of top and tie wefts also makes it possible to use a material for the top weft (paper side) that supports the transverse stability of the fabric,
• a polyester material whereas in the known solutions mentioned at the outset, when using a pair of binding wefts, both materials are of the same type and are to be optimized with regard to the ply connection, polyamides usually being used.
• the number of binding points that is to say the contact between the binding weft and the upper or lower chain of the paper side and the running side, does not decrease compared to the known solutions.
• the diameter of the binding thread corresponds to that of the excess weft, which leads to a high strength of the connection between the fabric layers.
• FIG. 3 is a plan view of a section of the top or paper side of the paper machine screen according to the invention.
• Fig. 6 is a plan view of the top or paper side of a second
• Fig. 9 is a plan view of the top or paper side of a third embodiment corresponding to the first embodiment, but realized with a changing weft sequence of the top and binding weft.
• the paper machine screen consists of two individual fabrics, the upper individual fabric or upper fabric forming the paper side and the individual fabric below it represents the running side or the lower fabric
• the upper single fabric stands from a set of weft threads 2 as upper weft threads and warp threads 1 as upper warp threads.
• the underlying running side is also formed from a set of weft threads 6 as weft threads and warp threads 5 as lower warp threads.
• the known solution has a plain weave and the lower fabric is designed as a five-shaft fabric with reference to a repeat. As shown in FIG.
• the two individual fabrics are connected to one another via a binding weft thread 3, a plurality of binding thread threads 3 (not shown) being arranged in succession in and out of the drawing plane and thus producing the necessary connection of the individual fabric layers for the paper machine screen ,
• the binding threads 3 are used in the direction of the fabric in front of and behind the top weft threads 2 in order to establish the connection of the individual fabric layers, so that the actually very homogeneous top side of the paper side of the screen is disadvantageously changed in such a way that it is in the Practice can lead to unwanted markings in the paper. So that the known binding weft threads 3 interfere as little as possible, they are made ever thinner, so that the use of the known paper machine screens can result in separation of the individual fabric layers and consequently failure of the screen as such.
• two binding weft threads 3 and 3 ' are used, the diameter of which is in particular chosen to be greater than the diameter of the known binding weft thread 3 according to FIG. 1.
• the plain weave of the upper side is realized by the combination of two binding threads 3, 3'.
• Binding threads 3 and 3 ' are present in different possible drawing levels in a row.
• a major disadvantage of this known solution is that the upper warp threads 1 are not supported at the crossing points of the binding wefts 3 and 3 '.
• FIG. 3 shows a section of the top view of the top or paper side of the paper machine screen according to the invention and the section AA according to FIG. 4 relates to the view of the top weft without binding weft, whereas the section BB relates to the view of the top weft with binding weft according to FIG. 3.
• FIG. 5 shows how the connection of the two individual fabric layers for the paper and the running side is realized by binding threads 3, of which excerpts of the course of such a binding thread 3 is shown by way of example in FIG.
• the upper weft thread 2 thus also runs evenly at the point at which a weave is made without being integrated into the lower fabric. Only at the points where the binding weft 3 runs over the top chain, a short exchange of the top weft 2 and the binding weft 3 is carried out. As a result, the warp threads 1 lying in between are supported at the points where they are drawn into the interior of the fabric through the binding thread 3, viewed from below as seen from below by the upper weft thread 2, with the larger diameter also being used for support Warp threads 5 of the lower weft 6 also contribute, in particular the lower warp thread 5, which lies in a vertical orientation under the warp thread 1 under and overlapped.
• the respective binding weft thread 3 delimits an angular dimension at the location of the overlap 7 of the assignable warp thread 1, which is the correspondingly formed angular dimension the underlying weft 2 is the same at this point.
• These angular dimensions are between 90 ° and 130 ° in these areas, depending on the type of paper machine sieve design. These angular dimensions create a kind of roof surface, namely once on the side of the overlap 7 and in the opposite way at the location of the underhand grip 8, which has proven to be favorable for the integration behavior and the overall force behavior of the paper machine screen.
• the inventive binding solution which is designed as a five-shaft weave in relation to a repeat, provides that four warp threads 5 underlaps and one warp thread 5 are overlapped in succession from the weft threads 6 of the lower fabric, the respective binding weft thread 3 at the location of this overlap 9 rising obliquely from the lower fabric changes into the upper fabric.
• the respective weft thread 3 has essentially the same diameter as the respective weft thread 2 of the individual fabric on the paper side.
• the warp threads 5 and the weft threads 6 of the lower fabric that is to say on the running side, each have a larger diameter than the assignable thread systems on the top or paper side of the paper machine wire.
• the respective overlap 7 of the respective binding thread 3 is subsequently separated from three interposed warp threads 1 with respect to a weft thread 2, the binding weft thread 3 at the location of the middle warp thread 1 of this group of three Warp thread 5 engages under the short weft 6 shortly before the overlap 9.
• these can consist of different materials, preferably to increase the transverse stability of the screen, the upper weft threads 2 consist of a polyester material and the binding weft threads 3 consist of a polyamide material.
• the upper weft thread 4 according to FIG. 4 corresponds in its design to the upper weft thread 2 with the binding weft thread 3 shown in front of it. The different numbering was chosen only in order to achieve a better understanding of the fabric pattern in the top view in the representation according to FIG. 3 ,
• this embodiment largely corresponds to the first embodiment described first; only instead of a five-shaft base was here for that
• a four-shaft weave is used for the lower fabric or the underside (running side). 8
• the warp thread 1 overlapped by the binding thread 3 and underneath the upper weft thread 2 is in turn supported by a warp thread 5 of the lower fabric lying vertically underneath, the weft thread 6 running above the lower warp thread 5 at the supporting point.
• the binding of the binding thread 3 then takes place for the lower fabric in the region of three successive lower warp threads 5, the middle lower warp thread 5 of a group of three being covered by the binding thread 3 and the two adjacent lower warp threads 5 being overlapped by the binding thread 3 in this way.
• the roof-like configuration in the region of the overlap 7 for the upper warp thread 1 finds its correspondence in a parallel arrangement, with the overlap 9 below of the supporting lower warp thread 5 by the weft thread 6.
• the order of top weft 2 with binding weft 3 is changed, with the result that all floating gene of the warp threads 1 have the same length L despite the slightly offset binding points.
• This ensures that the warp twists lie both in the transverse direction and in the longitudinal direction in one plane at the top, which has a favorable effect with regard to a low possible marking of the paper and a high strength of the screen.
• a high degree of stability is achieved with the paper machine screen solution according to the invention; the sieve has a very good drainage performance and is also inexpensive to manufacture.

Landscapes

• Paper (AREA)
• Woven Fabrics (AREA)
• Developing Agents For Electrophotography (AREA)
• Storage Of Web-Like Or Filamentary Materials (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Glass Compositions (AREA)

Applications Claiming Priority (3)

Publications (3)

Family

ID=32103452

Family Applications (1)

Country Status (9)

Families Citing this family (12)

Family Cites Families (19)

• 2002
  • 2002-11-16 DE DE10253491A patent/DE10253491B3/de not_active Expired - Lifetime
• 2003
  • 2003-10-24 ES ES03811353.6T patent/ES2333009T5/es not_active Expired - Lifetime
  • 2003-10-24 AU AU2003276162A patent/AU2003276162A1/en not_active Abandoned
  • 2003-10-24 AT AT03811353T patent/ATE444393T1/de active
  • 2003-10-24 WO PCT/EP2003/011776 patent/WO2004046458A1/fr active Application Filing
  • 2003-10-24 DE DE50311978T patent/DE50311978D1/de not_active Expired - Lifetime
  • 2003-10-24 US US10/530,724 patent/US7373957B2/en not_active Expired - Lifetime
  • 2003-10-24 CN CNA2003801016789A patent/CN1705790A/zh active Pending
  • 2003-10-24 JP JP2004552491A patent/JP4464278B2/ja not_active Expired - Lifetime
  • 2003-10-24 EP EP03811353.6A patent/EP1565613B2/fr not_active Expired - Lifetime

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events