FABRIC FOR A FIBER WEB PRODUCING MACHINE AND A METHOD FOR MAKING THE SAME

Abstract

A fabric for a machine for producing a fiberweb, the fabric including a woven base structure including a first base element and a second base element, wherein the first base element includes a first flat woven base material and the second base element includes a second flat woven base material, wherein the first flat woven base material has a length of twice a length of the fabric and is folded in a middle, creating a first two-ply element and a first fold, wherein the second flat woven base material also has a length of twice the length of the fabric and is folded in a middle, creating a second two-ply element and a second fold, and wherein the first base element and the second base element is arranged so that at least one ply of the first two-ply element is positioned between plies of the second two-ply element.

Claims

1. A fabric for a machine for producing a fiber web, the fabric comprising: a woven base structure including a first base element and a second base element, wherein the first base element includes a first flat woven base material and the second base element includes a second flat woven base material, wherein the first flat woven base material has a length of substantially twice a length of the fabric and is folded substantially in a middle, creating a first two-ply element and a first fold, wherein the second flat woven base material also has a length of substantially twice the length of the fabric and is folded substantially in a middle, creating a second two-ply element and a second fold, and wherein the first base element and the second base element is arranged so that at least one ply of the first two-ply element is positioned in a sandwich-manner between two plies of the second two-ply element.

2. The fabric according to claim 1, wherein the first base element and the second base element is arranged so that only one ply of the first two-ply element is positioned in a sandwich-manner between the two plies of the second two-ply element.

3. The fabric according to claim 1, wherein the first base element and the second base element is arranged so that both plies of the first two-ply element are positioned in a sandwich-manner between the two plies of the second two-ply element.

4. The fabric according to claim 1, wherein the fabric is on-machine-seamable having first seaming loops along a first widthwise edge which first seaming loops are formed by MD yarns of the first flat woven base material at the first fold, and having second seaming loops along a second widthwise edge which second seaming loops are formed by MD yarns of the second flat woven base material at the second fold.

5. The fabric according to claim 1, wherein the first flat woven base material is at least temporarily fixed to the second flat woven base material by at least one row of yarn that is stitched close and parallel to the first fold or to the second fold.

6. The fabric according to claim 1, wherein a fiber web side ply, i.e. a ply of the first two-ply element or of the second two-ply element that is positioned on a fiber web side of the fabric, or a roll side ply, i.e. a ply of the first two-ply element or of the second two-ply element that is positioned on a roll side of the fabric, is slightly longer than two center plies, i.e. two plies that are positioned in a sandwich-manner between the fiber web side ply and the roll side ply.

7. The fabric according to claim 1, wherein MD yarns are bonded to CD yarns of the first flat woven base material in the areas that extend along free widthwise edges of the first flat woven base material or MD yarns are bonded to CD yarns of the second flat woven base material in areas that extend along free widthwise edges of the second flat a woven base material.

8. The fabric according to claim 1, wherein the first flat woven base material or the second flat woven base material has a single layer weave.

9. The fabric according to claim 1, wherein the first flat woven base material or the second flat woven base material has a plain weave structure.

10. The fabric according to claim 1, further comprising: fibrous batt material needled onto at least one side of the woven base structure.

11. The fabric according to claim 10, wherein the fabric is a papermaker's press felt.

12. A method of making a fabric for a machine for producing a fiber web, the fabric including a woven base structure including a first base element and a second base element, wherein the first base element includes a first flat woven base material and the second base element includes a second flat woven base material, wherein both the first flat woven base material and the second flat woven base material have a length of substantially twice a length of the fabric, the method comprising: folding the first flat woven base material substantially in a middle, thus creating a first two-ply element and a first fold, folding the second flat woven base maternal substantially in a middle, thus creating a second two-ply element and a second fold, and arranging the first base element and the second base element so that at least one ply of the first two-ply element is positioned in a sandwich-manner between two plies of the second two-ply element.

13. The method according to claim 12, further comprising: at least temporarily fixing the first flat woven base material to the second flat woven base material by at least one row of yarn that is stitched close and parallel to the first fold or to the second fold.

14. The method according to claim 12, further comprising: removing CD yarns from the first flat woven base material at the first fold to create first seaming loops, and removing CD yarns from the second flat woven base material at the second fold to create second seaming loops.

15. The method of claim 14 further comprising: intermeshing the first seaming loops and the second seaming loops to create a seam channel; and inserting a pintle into the seam channel to convert the fabric into an endless form.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1A illustrates a side view of a first flat woven and folded base material according to a first embodiment of the present invention;

[0030] FIG. 18 illustrates a side view of a second flat woven and folded base material according to a first embodiment of the present invention:

[0031] FIG. 1C illustrates a side view of a combined arrangement of the first flat woven and folded base material of FIG. 1A and the second flat woven and folded base material of FIG. 18;

[0032] FIG. 1D illustrates a side view of the arrangement of FIG. 1C with some additional stitches;

[0033] FIG. 2A illustrates a side view of a first flat woven and folded base material according to a second embodiment of the present invention;

[0034] FIG. 2B illustrates a side view of a second flat woven and folded base material according to a second embodiment of the present invention;

[0035] FIG. 2C illustrates a side view of a combined arrangement of the first flat woven and folded base material of FIG. 2A and the second flat woven and folded base material of FIG. 2B;

[0036] FIG. 2D illustrates a side view of the arrangement of FIG. 2C with some additional stitches.

DETAILED DESCRIPTION OF THE INVENTION

[0037] FIGS. 1A-1D are schematic drawings illustrating the manufacturing process of a first preferred embodiment of a fabric according to the present invention. In reality, such a fabric of a modern fiber web making machine may have a width of from 5 to over 33 feet and a length of from 40 to over 400 feet.

[0038] FIG. 1A shows a first flat woven base material 10 having a length of substantially twice the length of the final fabric and being folded substantially in the middle, thus creating a first two-ply element with a first ply 12 and a second ply 14 that are connected to each other by a first fold 16. Thus, the first flat woven base material 10 forms a first base element 100. Advantageously, the first flat woven base material 10 exhibits a simple single layer plain weave structure.

[0039] Similarly, FIG. 1B shows a second flat woven base material 20 also having a length of substantially twice the length of the final fabric and being folded substantially in the middle, thus creating a second two-ply element with a first ply 22 and a second ply 24 that are connected to each other by a second fold 26. Thus, the first flat woven base material 20 forms a second base element 200. Advantageously, the second flat woven base material 20 also exhibits a simple single layer plain weave structure.

[0040] FIG. 1C shows an arrangement of the first base element 100 and the second base element 200 wherein in this particular embodiment the first base element 100 and the second base element 200 are arranged in such a way that at least the second ply 14 of the first two-ply element is positioned in a sandwich-manner between the two plies 22, 24 of the second two-ply element. At the same time the first ply 22 of the second two-ply element is positioned in a sandwich-manner between the two plies 12, 14 of the first two-ply element. Thus, the arrangement has four plies stacked one above the other.

[0041] To make the fabric on-machine-seamable, CD yarns at the first fold 16 are removed from the first flat woven base material 10 so that the MD yarns at the first fold 16 form first seaming loops along a first widthwise edge of the fabric, and also CD yarns at the second fold 26 are removed from the second flat woven base material 20 so that the MD yarns at the second fold 26 form second seaming loops along a second widthwise edge of the fabric. When the final fabric is threaded through the fiber web making machine it can be easily made endless by intermeshing the first seaming loops and the second seaming loops to create a seam channel, and by inserting a pintle into the seam channel.

[0042] As shown in FIG. 1D, the first flat woven base material 10 can beat least temporarilyfixed to the second flat woven base material 20 by rows of yarn 310 that are stitched close and parallel to the first fold 16 and to the second fold 26, respectively. Thus, the woven base structure 300 of the fabric is substantially completed.

[0043] Advantageously, especially if fabric is to be used as a press felt, a batt material is needled onto at least one side of the woven base structure 300.

[0044] As can be seen in the figures, the first flat woven base material 10 and the second flat woven base material 20 are not exactly folded in their middle, resulting in that the first ply 12 of the first flat woven base material 10 is slightly longer than the second ply 14 of the first flat woven base material 10 and that the first ply 22 of the second flat woven base maternal 20 is slightly shorter than the second ply 24 of the second woven base material. This allows to move the free ends of the longer plies 12 and 24 slightly over the seam on both, the fiber web side and the roll side of the fabric, thus, reducing the risk of seam marking.

[0045] FIGS. 2A-20 are just schematic drawings illustrating the manufacturing process of a second preferred embodiment of a fabric according to the present invention. The second embodiment is very similar to the first embodiment shown in FIG. 1A-1D, so that like numerals represent like elements and only the differences between the two embodiments will be discussed in the following. For the like elements it is referred to the above description of the first embodiment.

[0046] In this embodiment, the first flat woven base material 10 and the second flat woven base material 20 are folded substantially in their respective middle, wherein the length of the second flat woven base material 20 is slightly smaller than the length of the first flat woven base material 10. Furthermore, both, the first ply 22 and the second ply 24 of the second flat woven base material 20 are positioned in a sandwich-manner between the first ply 12 and the second ply 14 of the first flat woven base material 10. This allows to move the free ends of the two plies 12 and 14 of the first flat woven base material slightly over the seam on both, the fiber web side and the roll side of the fabric, thus, reducing the risk of seam marking.

REFERENCE NUMERALS AND DESIGNATIONS

[0047] 10 first flat woven base material

[0048] 12 first ply of the first flat woven base material 10

[0049] 14 second ply of the first flat woven base material 10

[0050] 16 first fold

[0051] 20 second flat woven base material

[0052] 22 first ply of the second flat woven base material 20

[0053] 24 second ply of the second flat woven base material 20

[0054] 26 second fold

[0055] 100 first base element

[0056] 200 second base element

[0057] 300 woven base structure

[0058] 310 rows of yarns (stitches)