RU2703570C2 - Three-layer fabric for paper-making machine - Google Patents

Abstract

FIELD: textile.SUBSTANCE: fabric (100) for a paper-making machine comprises rapport (104) of fabric, which contains eight upper MD threads (1–8) and eight lower MD threads (9–16), which pass in a longitudinal (Rp) direction; three upper CMD threads (P6, P10, P14) interwoven only with upper MD threads (1–8); three lower CMD threads (MC5, MC9, MC13) interwoven only with lower MD threads (9–16); and two pairs of binding threads (L7, L8; L11, L12), interlaced both with upper MD threads (1–8), and with lower MD threads (9–16); where the binding threads (L7, L8; L11, L12) of each pair cross each other under corresponding transition threads (T); binding threads (L7, L8; L11, L12) of each pair, together, only isolated transient threads (T) are left open on upper surface of fabric (100), all of which are separated from each other in transverse direction by a plurality of adjacent upper MD threads (1–8).EFFECT: disclosed is a three-layer fabric for a paper machine.18 cl, 1 tbl, 7 dwg

Description

Technical field

The present invention relates to tissue for a papermaking machine, in particular intended for use as a fabric for forming on a forming portion of a papermaking machine.

State of the art

The traditional grid section of the papermaking process mainly includes three successive steps carried out in the respective sections of the paper machine: the forming section, the pressing section, and the drying section.

At the formation site, an aqueous suspension of cellulose fiber (and any other possible components) is deposited on the so-called fabric for formation, or cloth, which is a ribbon-like cloth in the form of a closed loop and supported by shafts. Removing water from the suspension through the fabric to form leads to the gradual formation of a wet ribbon of paper material with a remaining, still relatively high water content. Additional water removal takes place at the press site, on which the paper material is pressed by passing through one or more pairs of rolls. The paper material is then sent to the drying section to finally remove moisture. The paper formed in this way is ready for the next stages of finishing and packaging.

In the following description, as is commonly accepted in the field regarding the method of making paper and similar materials, the terms “longitudinal direction” (abbreviated “MD”) and “transverse direction” (abbreviated “CMD”) are used to denote, respectively, the direction coinciding with a fabric feed direction for forming in a paper machine, and a direction parallel to the fabric surface, and a transverse direction perpendicular to the feed direction. Also, the direction, or orientation, of the warp and weft threads of the fabric for forming is indicated with reference to the longitudinal direction and the transverse direction.

Also, again, as is customary in a given industry, the surface of the forming fabric in contact with the pulp (i.e., the formed paper material) is considered the top surface of the fabric; and the opposite surface facing the machine is considered the bottom surface. This explanation is also applicable to the description of the spatial arrangement, in the vertical direction, of the threads in the fabric to form.

Some characteristics of tissue for paper machines are of particular importance, for example, bearing capacity and filtering ability, especially in the area for forming.

In addition, fabrics for paper machines must have very high stability even when moving at high speeds; high permeability to reduce the amount of water held in suspension during transfer to the pressing section; and reduced energy consumption when handling it.

Although various types of fabrics are known for paper machines, in particular for use in the forming section, improvements in this area still seem to exist, for example, in terms of mechanical strength, stability, durability, drainage and quality of the formed paper.

For example, document WO2014 / 091410 describes a paper machine fabric comprising: an upper layer formed of upper transverse threads interwoven with only upper longitudinal threads; a lower layer formed from lower transverse threads intertwined only with lower longitudinal threads; where the binder yarns are intertwined with both the upper and lower longitudinal yarns, and thus the upper and lower layers are connected.

On the other hand, it is known that even small changes in the structure can unpredictably affect the performance of the fabric and, thus, the properties of paper made using said fabric. It is well known in the art that undoubtedly even very similar structures can behave in completely different ways.

Indeed, the structure of the fabric directly affects the quality of the paper web formed on the fabric in close contact with this paper web, but the direction in which structural changes in the fabric can affect the quality of the paper is not predictable.

Disclosure of invention

Thus, it is an object of the present invention to provide a tissue for a paper machine that maintains these characteristics to a satisfactory degree, which ensures, in particular: high efficiency, high drainage ability, resistance and time stability, and high quality of the formed paper is ensured.

The present invention, therefore, relates to tissue for a paper machine, as defined essentially in paragraph 1 of the attached claims; and to its additional characteristics defined in the dependent claims.

The present invention also relates to the use of said fabric in a papermaking machine, and specifically, to a machine forming portion as defined in paragraph 18 of the appended claims.

The invention created a fabric for a paper machine, which, like some known fabrics, has a two-layer structure, each layer of which is formed from independent weft and warp threads, and a binder system formed from pairs of binder threads; however, the invention is characterized in that the fabric has a special structure, due to which it is possible to obtain a fabric having high efficiency, high drainage ability, durability and stability over time, using which ensures high quality of the formed paper.

Brief Description of the Drawings

The invention is further described in the following examples of non-limiting embodiments with reference to the accompanying drawings, in which:

figure 1 is a schematic view in plan of the upper layer of fabric according to the invention, which shows a rapport of fabric;

figure 2 is a schematic view in plan of the lower layer of fabric shown in figure 1;

on figa, 3b, 3c - sections IIIa-IIIa, IIIb-IIIb, IIIc-IIIc in figures 1 and 2, respectively;

4 is a schematic plan view of an alternative top layer of fabric according to the invention;

figure 5 is a schematic view in plan of the lower layer of fabric shown in figure 4;

on figa, 6b, 6c, 6d - section VIa-VIa, VIb-VIb, VIc-VIc, VId-VId in figure 4 and 5, respectively;

7 is a view in the longitudinal direction (in the direction of the base) of a piece of fabric according to the invention.

The best embodiment of the invention

Reference numeral 100 (see FIGS. 1-3) denotes generally a fabric for a paper machine, in particular fabric for forming, for use in a forming section of a paper machine.

The fabric 100 is a three-layer 16-heald fabric and contains the upper layer 101 and the lower layer 102, formed, as usual, using the appropriate rapports, which together form one rapport 104 of the fabric; 1 and 2 show one fabric rapport 104; it is clear that in commercial and industrial applications, rapport 104, as well as rapport of individual layers 101, 102, can be repeated several times, both in the longitudinal direction and in the transverse direction, to form a fabric 100 having suitable sizes for use in a paper machine .

In general, fabric 100 is formed from longitudinal warp yarns that extend in the longitudinal (MD) direction, and from transverse weft yarns substantially perpendicular to previous yarns that extend in the transverse (CMD) direction. In the following description (and as is commonly accepted in the art), longitudinal warp yarns that extend in the longitudinal direction are designated, for brevity, “MD yarns” and transverse weft yarns that extend in the transverse direction are designated “CMD yarns”.

In this case, the rapport 104 of the fabric 100 contains: eight upper MD yarns 1-8; three upper CMD threads P6, P10, P14; eight lower MD yarns 9-16; three lower CMD yarns MC5, MC9, MC13 and four binder yarns L7, L8, L11, L12, containing respective supporting parts 115 and corresponding connecting parts 116.

The upper layer 101 contains the upper MD yarns 1-8 and the upper CMD yarns P6, P10, P14, as well as the supporting parts 115 of the binder yarns L7, L8, L11, L12.

The lower layer 102 contains the lower MD yarns 9-16 and the lower CMD yarns MC5, MC9, MC13, as well as the binder portions 116 of the binder yarns L7, L8, L11, L12, which are omitted to bind the lower MD yarns 9-16.

The upper CMD yarns P6, P10, P14 are interlaced only with the upper MD yarns 1-8, and the lower CMD yarns MC5, MC9, MC13 are interwoven only with the lower MD yarns 9-16. Binding threads L7, L8, L11, L12 connected the upper MD filaments 1-8 with the lower MD filaments 9-16.

The upper MD yarns 1-8 and the upper CMD yarns P6, P10, P14 are interlaced so that each upper CMD yarn P6, P10, P14 extends over three adjacent upper MD yarns and under the next upper MD yarn, etc. For example, as shown in FIG. 3a, the upper CMD yarn P6 extends under the upper MD yarn 1, above the upper MD yarns 2, 3, 4, below the upper MD yarn 5, above the upper MD yarns 6, 7, 8, etc.

According to the same figure, all the upper CMD yarns P6, P10, P14 are located, but the upper CMD yarns are laterally shifted by one or two upper MD yarns.

In particular, the upper CMD thread P10 is offset by the upper MD thread relative to the previous upper CMD thread P6 (then the CMD thread P10 passes under the upper MD threads 2, 6 and above the remaining upper MD threads 1, 3, 4, 5, 7, 8); and the upper CMD thread P14 is offset by two upper MD threads relative to the previous upper CMD thread P10 (then the CMD thread P14 passes under the upper MD threads 4, 8 and above the remaining upper MD threads 1, 2, 3, 5, 6, 7).

Layers 101, 102 are joined and knitted together to form fabric 100 using binder threads L7, L8, L11, L12.

Each binder thread L7, L8, L11, L12 contains, in a rapport 104 fabric, supporting part 115, which is located above the upper MD threads 1-8 and intertwined with them; and a binder portion 116, which is located under the upper MD yarns 1-8 and intertwined with the lower MD yarns 9-16.

Binding threads L7, L8, L11, L12 are arranged in pairs between pairs of adjacent upper CMD threads P6, P10, P14. Each pair of tie threads L7, L8 and L11, L12 is located between two adjacent upper CMD threads P6, P10, P14.

In particular, a pair of tie threads L7, L8 is located between the upper CMD threads P6, P10, and a pair of tie threads L11, L12 is located between the upper CMD threads P10, P14.

Binding threads L7, L8; L11, L12 of each pair (although presented as side-by-side, for clarity, with respect to the schematic views shown not to scale in FIGS. 2 and 3) are intertwined together and vertically overlapped so that the supporting parts 115 the binder yarn of the pair was superimposed on the binder portion 116 of another binder yarn of the pair, and vice versa; the two tie yarns of the pair intersect each other along some of the upper MD yarns 1-8, which are composed of the corresponding transition yarns T, which pass over the two tie yarns of the pair and under which the tie yarns of the pair intersect each other, which comprise the transition between the supporting parts 115 and connecting parts 116.

Binding threads L7, L8; L11, L12 of each pair, together, are left open (on the upper surface of the fabric 100) only single isolated transition threads T. In each pair of binder threads L7, L8; L11, L12, each transition thread T is separated from the other transition threads T in the transverse direction by a plurality of other upper MD threads; in other words, the transition filaments T are all transversely separated from each other by a plurality of other upper MD filaments. Thus, there are only individual transition fibers T (not adjacent to each other) that are regularly separated from one another in the transverse direction by a plurality of other upper MD threads. Instead, there are non-contiguous transition filaments T. In particular, the transition filaments T are separated from each other by the other three adjacent upper MD filaments.

With respect to the pair of tie threads L7, L8, the transition threads T are the upper MD threads 4 and 8; with respect to the pair of tie threads L11, L12, the transition threads T are the upper MD threads 3 and 7. Transition threads T of each pair of tie threads L7, L8; L11, L12 are separated by three adjacent upper MD threads; transition threads T of two pairs of binder threads L7, L8; L11, L12 are shifted on one upper MD thread.

Each of the binder yarns L7, L8, L11, L12 extends above the three adjacent upper MD yarns 1-8 (defining the supporting portion 115) and under the next five adjacent upper MD yarns 1-8 (defining the binder 116).

Binding threads L7, L8; L11, L12 of each pair are intertwined so that the supporting parts 115 of one are located above the connecting parts 116 of the other.

Two binder threads L7, L8; L11, L12 of each pair, together, pass over three adjacent upper MD threads, under the next upper MD thread, etc., according to the same pattern (i.e. according to the same weave) of the upper CMD threads P6, P10, P14. Pairs of binder threads L7, L8; L11, L12, however, are offset relative to adjacent upper CMD yarns (between which a pair of binder yarns are located) so that they extend above the upper MD yarns that are left open by adjacent adjacent upper CMD yarns.

Both binding threads L7, L8, L11, L12 pairs pass under the transition threads T.

For example, the binder thread L7 (see FIG. 3b) extends above the upper MD filaments 1, 2, 3 by its own supporting portion 115 and extends below the upper MD filaments 4, 5, 6, 7, 8 by its own bonding portion 116; binder thread L8 (see FIG. 3c) extends above the upper MD filaments 5, 6, 7 by its own supporting portion 115, and it passes below the upper MD filaments 1, 2, 3, 4, 8 by its own bonding portion 116. Both binders threads L7, L8 pass under the transition threads T defined by the upper MD threads 4 and 8.

In fabric rapport 104, each binder thread L7, L8, L11, L12 binds (passes over) a triple of adjacent upper MD yarns 1-8 and binds (passes under) a lower MD yarn 9-16, in particular, an equal amount of transverse displacement positions (for example, two positions or four positions) relative to the triple of the upper connected MD threads.

For example, the binder thread L7 (see FIG. 3b) extends above (i.e., binds) the upper MD filaments 1, 2, 3 and below (ie, binds) the lower MD filament 15, which is shifted four positions in the transverse direction relative to the upper MD of the yarn 3; the binder thread L8 (see FIG. 3c) extends above the upper MD filaments 5, 6, 7 and below the lower MD filament 9, which is shifted two positions in the transverse direction relative to the upper MD filament 7.

In another pair of binder yarns L11, L12, the binder yarn L11 passes over (i.e. binds) the upper MD yarns 1, 2, 8 and under the upper MD yarns 3, 4, 5, 6, 7, and passes under (i.e. e. binds) the lower MD thread 14, which is offset by four positions in the transverse direction relative to the upper MD thread 2; the binder thread L12 extends above the upper MD filaments 4, 5, 6, under the upper MD filaments 1, 2, 3, 7, 8 and under the lower MD filament 10, which is also shifted four positions in the transverse direction relative to the upper MD filament 7.

Finally, each binder yarn L7, L8, L11, L12 extends over three adjacent upper MD yarns 1-8 and under the next five adjacent upper MD yarns 1-8, etc .; and under one lower MD filament 9-16 and above all subsequent lower MD filaments 9-16, etc.

Thus, the binder yarns L7, L8, L11, L12 and the upper CMD yarns P6, P10, P14 form a four-thread satin structure (four-knit satin) with upper MD yarns 1-8 (see FIG. 1).

The lower layer 102 (see FIG. 2) contains the lower MD yarns 9-16, the lower CMD yarns MC5, MC9, MC13 and the binder portions 116 of the binder yarns L7, L8, L11, L12.

The lower CMD threads MC5, MC9, MC13 are interwoven with the lower MD threads 9-16 with the sequence “over-2 / sub-6”. For example, as shown in FIG. 3a, the lower CMD yarn MC5 extends above the lower MD yarns 10, 11 and below the lower MD yarns 9 and 12-16.

The other lower CMD yarns MC9, MC13 are arranged according to the same “over-2 / sub-6” pattern relative to the lower MD yarns 9-16, but each is offset relative to the adjacent lower CMD yarn in the transverse direction (in particular, one position) in this way so that a six-thread twill structure with an intermittent pattern is formed.

The lower layer 102 also contains binder portions 116 of the binder yarns L7, L8, L11, L12.

As already described, each binder yarn L7, L8, L11, L12 binds, in a rapport 104 of fabric, three adjacent upper MD yarns 1-8 and one lower MD yarn 9-16; in particular, each binder yarn L7, L8, L11, L12 binds (by skipping from the top) three adjacent MD yarns 1-8 and (by skipping from the bottom) one lower MD yarn 9-16, which is shifted two or four positions in the transverse direction relative to the triple of the upper MD filaments (specifically, regarding the third and last upper MD filaments of the triple).

For example, the binder thread L7 (see FIG. 3b) passes over (i.e., binds) the upper MD filaments 1, 2, 3 and passes under (i.e., binds) the lower MD filament 15, which is offset four positions transverse to the upper MD yarn 3; the binder thread L8 (see FIG. 3c) extends above the upper MD filaments 5, 6, 7 and below the lower MD filament 9, which is shifted two positions in the transverse direction relative to the upper MD filament 7.

Each binder yarn L7, L8, L11, L12 extends above the three adjacent upper MD yarns and under the next five upper MD yarns, etc .; and under one bottom MD thread, and over the next seven bottom MD threads, etc.

Binding threads L7, L8; L11, L12 of each pair, together, relative to the upper MD yarns 1-8, are arranged according to a sequence identical to the sequence of the upper CMD yarns P6, P10, P14 relative to the upper MD yarns 1-8. In particular, the binder yarns L7, L8, L11, L12 of each pair are arranged according to the “over-3 / sub-1” sequence relative to the upper MD yarns 1-8, which is, specifically, the same sequence as the upper CMD yarns P6 , P10, P14 relative to the upper MD yarns 1-8.

Again, the binder threads L7, L8; L11, L12 of each pair, together, are located according to the sequence “under-1 / above-5” (pairs of tie threads L7, L8), or the sequence “under-1 / above-3” (pairs of tie threads L11, L12), relative lower MD yarns 9-16.

Alternatively, two pairs of tie threads L7, L8; L11, L12 can follow the same sequence (and, in particular, one of the two designated threads) is preferably shifted one position in the transverse direction relative to the other.

The interweaving of the L7, L8, L11, L12 yarns with the upper MD yarns 1-8 and the lower MD yarns 9-16 may, however, take other forms.

As can be seen, in General, from the drawings, in the rapport 104 of the fabric 100 there are eight lower MD threads and eight upper MD threads.

In the fabric 100, there is a ratio between weft threads and warp threads of 4: 1.

It is assumed that the ratio between the weft yarns and the warp yarns is the ratio between the number of weft yarns that are repeated to form the fabric in the longitudinal direction, and the number of warp yarns that are repeated in the transverse direction to form the fabric.

In fabric 100, four weft threads are provided for each warp yarn; this corresponds to the fabric manufacturing process on the loom: four weft threads are introduced onto each warp thread.

In a cross section (a cross section perpendicular to the longitudinal direction), the fabric 100 thus comprises a sequence of four weft yarns that is repeated in the longitudinal direction with respect to each warp yarn (which is alternately upper or lower yarn depending on the weave with the weft yarns).

In other words, the rapport 104 of the fabric is formed from one main thread (MD thread), which accounts for every four weft threads (CMD threads): for each main thread (which may be the upper MD thread 1-8 or lower MD thread 9-16, depending on the weave with weft CMD yarns) in reality there is: one upper CMD yarn (one of the P6, P10, P14 yarns), one lower CMD yarn (one of the MC5, MC9, MC13 yarns) and a pair of binder yarns (L7, L8 ; L11, L12).

On figa, 3b, 3c, which shows the main threads, they are schematically shown in the form of superimposed pairs, for the formation of two layers; in fact, the main threads are arranged in this way due to the weave effect with weft threads, but in the transverse direction there is only one main thread, which is repeated.

The ratio of weft threads and warp threads, comprising 4: 1, reflects the mode of production of tissue 100; with each beat of the batan (or with each insertion of the weft), four successive weft threads fall on each main thread.

The fabric 100 thus contains the main thread for every four prokidok weft threads. Each upper or lower MD yarn is connected, with each throwing or each stroke of the batan, to the upper CMD yarn, the lower CMD yarn and to a pair of binder yarns.

Specialists in the art should understand that these fabrics, according to the present invention, can be given various shapes.

For example, with respect to what has been previously described, the number and / or position of the binder yarn relative to the number and / or position of the upper CMD yarns can be varied (for example, there may be a binder yarn for every two or three upper CMD yarns, or there may be two or three , or more binder threads for each top CMD thread).

Also, the number of upper and lower CMD yarns in a rapport of fabric can be varied relative to what has been described and illustrated simply by way of example.

In addition, all patterns of weaving or patterns described in relation to the layers 101, 102 may differ from those that have been illustrated and described; for example, the upper surface of the fabric does not have to be formed from a four-piece satin structure, as shown, but may be similar to a severe canvas, twill, curved twill, etc .; and the bottom surface of the fabric does not have to be a six-thread curvilinear twill structure, but may have other weaves, for example, curvilinear satin, plain weave (rough rough fabric), curvilinear twill weave, twill weave, etc. Again, additional alternative patterns of structure can be used in the fabric according to the present invention.

The threads can have various shapes (for example, a rounded or flattened section) and sizes.

The shape of the threads used in the fabric according to the invention can also be varied depending on the properties to be imparted to the finished product. For example, the yarns may be filaments, flat filaments, complex yarns, complex or elementary interwoven yarns, yarns of any kind or any combination thereof. The materials from which the yarns can be made can be materials commonly used in the art. For example, the yarns may be made of polyester, polyamide, polyamide / polyester, and the like. Technical specialists in this field can choose materials for threads as well as a function of the specific application for which the finished fabric is intended for use.

For example, the upper MD filaments, the upper CMD filaments and the binder filaments may have a diameter (the same or different) of about 0.10 mm to 0.25 mm; lower MD yarns may have a diameter of from about 0.12 mm to 0.30 mm; lower CMD yarns may have a diameter of from about 0.10 mm to 0.35 mm; these are just the dimensions given as examples; and yarns of other sizes may be used depending on specific requirements. The density of the threads in the fabric (i.e., the number of threads per unit length or width of the fabric) can also vary. For example, the density of threads in the upper surface can be from about 34 × 38 to 37 × 48 (the number of warp threads per 1 cm x the number of weft threads per 1 cm), and the total density of threads can vary in the range from about 66 × 74 to 78 × 96 (number of warp threads per 1 cm x number of weft threads per 1 cm).

A fabric with a ratio of 4: 1 and with a lower layer with a six-thread twill structure with an intermittent pattern made according to the invention has, for example, the characteristics shown in Table 1.

Table 1

A thread Dimensions Upper MD Lower MD Binder Upper CMD Lower CMD Thread Density (Top Surface) 37 × 44 * Thread Density (total) 74 × 88 *

(*) the number of warp threads per 1 cm x the number of weft threads per 1 cm.

4-6, in which parts similar or identical to those that have already been described are indicated by the same reference numbers, an alternative fabric 100 according to the invention is shown.

As shown in FIGS. 4 and 6a, the upper layer 101 also has a four-remise satin structure: the upper CMD filaments of which (only a pair of adjacent filaments P14, P2 are represented) are really intertwined with the upper MD filaments 1-8 with the sequence “above-3 / sub- 1 ”(where each upper CMD yarn extends above three adjacent upper MD yarns and under the next upper MD yarn, etc.).

As shown in FIGS. 5 and 6b, the lower layer 102 has the structure: the lower CMD yarns, of which only a pair of adjacent threads MC13, MC1 are represented, are actually interwoven with the lower MD yarns 9-16 with the sequence “above-3 / sub-1” (where each lower CMD yarn extends above one lower MD yarn and under the next three adjacent lower MD yarns, etc.).

Figures 4, 5, 6c and 6d show a pair of binder threads L15, L16, which are also intertwined as described above: with each binder thread L15, L16, a triple of adjacent upper upper MD yarns 1-8 are connected (and connected) (it passes under) the lower MD thread 9-16; in particular, it is shifted in the transverse direction by the same number of positions in the longitudinal direction (for example, by four positions) relative to the three connected upper MD yarns.

The binder yarn L15 (see FIG. 6c) passes over (i.e. binds) the upper MD yarns 1, 2, 3 and passes under (i.e. binds) the lower MD yarn 15, which is shifted four positions in the transverse direction relative to the upper MD filament 3; binder yarn L16 (see FIG. 6d) extends above the upper MD yarns 5, 6, 7 and below the lower MD yarn 11, which is also shifted four positions in the transverse direction relative to the upper MD yarn 7.

In all embodiments of the invention, the upper layer 101 and the lower layer 102 can also be bonded by means of binder threads extending in the transverse direction (i.e., in the weft direction), as described above, as well as in the longitudinal direction (i.e., in the direction basics).

To this end, as shown in FIG. 7, in the fabric rapport 104, at least a pair of superimposed MD filaments, where one upper MD filament and one lower MD filament are superposed one on another (which belong to the upper layer 101 and the lower layer 102, respectively) as an example, the upper MD filament 6 and the lower MD filament 14 located immediately below the upper MD filament 14 intersect one another in the longitudinal direction, i.e. in the direction of the warp, so that they make up a pair of warp, binder filaments MD6, MD14, while maintaining the weave patterns of both the upper layer 101 (for example: four <thread> satin) and the lower layer 102 (for example: six <thread> twill pattern with intermittent pattern).

The main binder threads MD6, MD14 of each pair are located directly one above the other and crossed with each other so that the same basic structure (four-thread atlas) is preserved. Each upper MD yarn 1-8 and each lower MD yarn 9-16 then retain their position in weaves, even if they act as the main binder yarn between the upper layer 101 and the lower layer 102.

In rapport 104 of the fabric, the main binder yarns MD6, MD14 cross each other only once.

In rapport 104, several pairs of superimposed MD yarns can cross each other, even all pairs, to determine the corresponding pairs of main binder yarns: preferably adjacent pairs of main binder yarns that cross each other, in offset positions, in the longitudinal direction.

It is understood that binders in the longitudinal direction (warp yarns) are applicable to all embodiments according to the invention and to all weave patterns of fabric 100 mentioned above and to others, which, moreover, fall within the scope of the invention.

According to an aspect of the invention, the fabric 100 described above is used in a papermaking process, in particular at a forming section of a paper machine. The process includes the steps of:

(A) providing fabric for the paper machine described above;

(B) deposition on the upper surface of the fabric of an aqueous suspension of cellulosic and / or paper material to be formed; and

(C) removing water from the suspension and / or from the paper material to be formed.

The mentioned process is essentially known and well understood by specialists in this field, therefore, a more detailed description of this process is not required here.

It remains to be understood that the object that is described and illustrated here can be further modified, and alternative solutions can be added to it that do not go beyond the scope of the invention defined in the attached claims.

Claims (28)

1. A three-layer fabric (100) for a paper machine, containing at least one fabric rapport (104), which contains: - a group of warp yarns or longitudinal (MD) yarns (1-16), which extend in the longitudinal (MD) direction and are divided into eight upper MD yarns (1-8) and eight lower MD yarns (9-16); - a group of weft threads or transverse (CMD) threads (P6, P10, P14; MC5, MC9, MC13; L7, L8, L11, L12), which extend in the transverse direction and specifically contain the top three CMD threads (P6, P10, P14 ), the three lower CMD yarns (MC5, MC9, MC13) and two pairs of binder yarns (L7, L8; L11, L12) containing the corresponding supporting parts (115) and the corresponding connecting parts (116); Where - the upper CMD yarns (P6, P10, P14) are interlaced only with the upper MD yarns (1-8) to form the upper layer (101) of fabric; - lower CMD yarns (MC5, MC9, MC13) are interlaced only with lower MD yarns (9-16) to form the lower fabric layer (102); - binder yarns (L7, L8; L11, L12) are interwoven with both the upper MD yarns (1-8) and the lower MD yarns (9-16) so that the upper layer (101) is connected with the lower layer ( 102); - binder threads (L7, L8; L11, L12) are arranged in pairs between pairs of adjacent upper CMD threads (P6, P10, P14); and binder yarns (L7, L8; L11, L12) of each pair cross each other under the corresponding transition yarns (T) that pass over both of the pair yarn characterized in that - binder filaments (L7, L8; L11, L12) of each pair, arranged so that together they leave only single isolated transition filaments (T) open on the upper surface of the fabric (100), all of which are separated from each other in the transverse direction a plurality of adjacent upper MD yarns (1-8); and - transition yarns (T) defined by the first pair of binder yarns (L7, L8) are shifted by one upper MD yarn relative to the transition yarns (T) defined by the second pair of binder yarns (L11, L12). 2. The fabric according to claim 1, in which the transition yarns (T) of each pair of binder yarns (L7, L8; L11, L12) are separated from each other by triples of adjacent upper MD yarns (1-8). 3. The fabric according to claim 1 or 2, in which the sequence of two binder yarns (L7, L8; L11, L12) of each pair, together, relative to the upper MD yarns (1-8), is the same as the sequence of the upper CMD filaments (P6, P10, P14) relative to the upper MD filaments (1-8). 4. The fabric according to one of the preceding paragraphs, in which two binder yarns (L7, L8; L11, L12) of each pair, together, pass over three adjacent upper MD yarns (1-8) and under the following upper MD yarns, etc. . 5. The fabric according to one of the preceding paragraphs, in which each binder yarn (L7, L8; L11, L12) passes over three adjacent upper MD yarns (1-8) and under the next five adjacent upper MD yarns (1-8) and t .d. and under one lower MD thread (9-16), and above all the following lower MD threads (9-16), etc. 6. The fabric according to one of the preceding paragraphs, in which pairs of binder yarns (L7, L8; L11, L12) are offset relative to adjacent upper CMD yarns (P6, P10, P14) so that they pass over the upper MD yarns (1-8 ), which are instead left open by adjacent upper CMD threads (P6, P10, P14). 7. The fabric according to one of the preceding paragraphs, in which each binder thread (L7, L8; L11, L12) binds, i.e. passes over the three adjacent upper MD threads (1-8) and binds, i.e. passes under one bottom MD thread (9-16), which is shifted in the transverse direction by an equal number of positions relative to the said three top MD threads. 8. The fabric according to claim 7, in which each connecting thread (L7, L8; L11, L12) has a triple of adjacent adjacent upper MD yarns (1-8) and one lower MD yarn (9-16), which is offset by two or four positions in the transverse direction relative to the third and last upper MD yarn of the triple. 9. The fabric according to one of the preceding paragraphs, in which each upper CMD thread (P6, P10, P14) passes over three adjacent upper MD threads (1-8) and under the next upper MD thread (1-8), etc. 10. The fabric of claim 9, wherein the upper CMD yarns (P6, P10, P14) are laterally offset by one or two upper MD yarns (1-8). 11. The fabric according to claim 9 or 10, in which the rapport (104) of the fabric is the first, second and third upper CMD threads (P6, P10, P14); moreover, the second upper CMD thread (P10) is offset by one upper MD thread relative to the previous first upper CMD thread (P6), and the third upper CMD thread (P14) is offset by two upper MD threads from the previous second upper CMD thread (P10). 12. The fabric according to one of the preceding paragraphs, in which the binder filaments (L7, L8; L11, L12) and the upper CMD filaments (P6, P10, P14) form a four-strand satin structure with the upper MD filaments (1-8). 13. The fabric according to one of the preceding paragraphs, in which the lower CMD yarns (MC5, MC9, MC13) are interwoven with the lower MD yarns (9-16) with the sequence “over-2 / sub-6”. 14. The fabric according to the preceding paragraph, in which each of the lower CMD threads (MC5, MC9, MC13) is shifted one position in the transverse direction relative to the previous lower CMD thread. 15. The fabric according to one of the preceding paragraphs, while the fabric (100) has a ratio between weft threads and warp threads of 4: 1. 16. The fabric according to one of the preceding paragraphs, in which the upper layer (101) and the lower layer (102) are also connected in the longitudinal direction, i.e. towards the base. 17. The fabric according to clause 16, in which in the rapport (104) of the fabric there is at least a pair of directly superimposed MD filaments (MD6, MD14), i.e. the upper MD thread and the lower MD thread, directly superimposed on one another, are crossed with each other in the longitudinal direction, i.e. in the direction of the warp, so that they form a pair of binder warp yarns (MD6, MD14), preserving the weave patterns of both the upper layer (101) and the lower layer (102). 18. The use of fabric (100) according to any one of the preceding paragraphs in a paper machine for transporting pulp and / or paper material to be formed.

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