FI78139B - VAEVD FILT SPECIELLT FOER PAPPERSINDUSTRIN. - Google Patents

Abstract

1. A woven band with n woof planes (a, b) particularly destined to be used in the papermaking industry, comprising woof threads (17) and warp threads (1, 2, 3, 4, 5, 6, 7, 8), the ends of which are pleated and folded back, said woven band further comprising loops (14) near the folds (15) serving to join them, the zones (C) neighbouring the folds having m woof planes, characterized in that the zone (C) near a fold (15) compises, for each armouring repeat of warp threads, a first group (G1) of warp threads (1, 2, 3, 4) forming a lower layer (20) of p woof planes (m > p > 1) and an upper layer (20') folded back on the lower layer (20) having m-p woof planes, and a second group (G2) of warp threads (5, 6, 7, 8) forming a lower layer (22) of q woof planes (1 =< q < p) and an upper layer (22') folded back on the lower layer (22) having m-q woof planes, some at least of the woof threads (1, 3, 5, 7) of each of said groups (G1, G2) serving to constitute loops (14) at the level of the fold (15).

Description

78139

This invention relates to a woven felt consisting of n weave layers and intended specifically for use in the paper industry, comprising weft yarns and warp yarns, the ends of which are folded and pressed down, and which said felt further comprises loops in connection with the folds to connect the felt and is formed in the zone adjacent to the folds m from the weft plane.

To connect the loops together, a pin can be used which is threaded through the loops inserted into each other's gaps, or coil springs are used which are first threaded through the loops and then connected to each other with the needles.

Such blankets are used especially in the paper industry, especially as drying blankets.

The felt is passed around the drying cylinders of a paper machine and then its ends are joined.

US-A-4250822 discloses a woven drying felt of this type, in which the folded parts are fastened by sewing.

However, these stitches prove to be quite brittle and prone to wear. In addition, they may leave marks on the paper.

The woven felt according to the invention, in which the use of stitches can be avoided, is characterized in that the zone adjacent to the fold comprises, for each sub-warp formed by the warp yarns, a first group of warp yarns forming a lower layer (m> p> 1) and an upper layer. printed on a lower layer having a mp weave, and a second group of warp yarns forming a lower layer (Kq <p) comprising q weave and an upper layer printed on the lower layer and comprising mq weave, in addition to which at least some the warp yarns form loops at the fold.

Because p is greater than q, there are weft planes (p-q) of which at least one weft plane is common to the lower layer of the first yarn group, which is also common to the upper layer of the second yarn group, ensuring interconnection of the two zones adjacent to the fold.

According to one embodiment of the invention, the zone adjacent to the fold is thicker than the actual felt without backward weaving (m> n). In this way, loops higher than the strength of the felt can be used, without, of course, exceeding the thickness of the zone close to the fold, so that no marks are formed on the paper and the loops are not worn.

Due to the excessive strength of the area near the fold, it is also possible to thread helical springs into the loops with a strength greater than that of the felt itself, without, however, exceeding the strength of the zone close to the fold. After the threads of both springs have been pushed into each other’s rest, they are connected with pins.

When p is selected to be equal to n, and when n is greater than 1, it is preferable to design a zone adjacent to the actual felt portion so that the first warp yarn group of the felt consists only of a lower layer and where the lower layer of the second warp yarn group comprises r weft level. the layer comprises a (nr) weft plane, with the second group of yarns terminating in this zone.

According to another embodiment of the invention, n is greater than 2 and the zone adjacent to the fold is of the same strength as the tissue itself (m = n).

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It should otherwise be noted that the warp yarns woven on the woven felt according to the invention are little or not constricted in the lower layers, which prevents internal stresses which cause deformation as well as deterioration of air permeability in congested areas, causing a decrease in water evaporation rate in the drying material.

In addition, the loops can be very dense. In fact, each loop is made of turned-down warp yarn so that it is in a plane perpendicular to the weft yarns.

The loops are thus space-consuming laterally, and 50 percent or more of the warp yarns can be used to form the loops.

On the other hand, the number of yarns in each group in each sub-warp should preferably be the same, in order to have the most favorable distribution of stresses in the fabric.

The invention will now be described in more detail in the light of certain embodiments, which are shown in the accompanying drawing as a non-limiting example.

Figure 1 shows a woven felt of a known type.

Figure 2 shows a head of a woven felt according to the invention having excessive strength.

Figures 3-6 show the possibility of manufacturing a felt before its processing in a threading machine.

Figure 7 shows the end of a woven felt according to the invention which does not have excessive strength.

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The woven felt of Figure 1 is of the type described in US-A-4250822.

The ends 11 of the felt 12 are folded back, pressed down and fastened with stitches 13. The loops 14 are in connection with the folds 15, and when the loops of the two ends are pushed into the gaps of each other, the connection of the ends can be locked with pins.

Figure 2 shows the end of a felt according to the invention.

The felt has two tissue levels a and b (n = 2). Weft yarns are described as dots. The end of the felt is divided into four zones A, B, C, D with the loops belonging to zone D. Each subwarp formed by the warp yarns comprises a first group G1 consisting of four warp yarns 1, 2, 3, 4 and a second group G2 consisting of four warp yarns 5, 6 , 7, 8. The total thickness of zone C is three weft levels a, b, c (m = 3).

The structure of the first group G1 is shown in the anterior plane, and that of the second group G2 in the posterior plane.

The warp yarns 1, 2, 3, 4 of the first group run in two weave planes a, b (p = 2) in zones A and B, as well as in zone C, where they form the lower layer 20. The warp yarns 1, 2, 3, 4 run in two weft yarns of plane a. below and then level b over one weft yarn, and so on. Zone A shows the actual felt. In zone D, the yarns 1 and 3 form two loops, while the yarns 2 and 4 are folded immediately against the weft yarns.

The yarns 1, 2, 3, 4 form an upper layer 20 'which is pressed against the lower layer 20, giving excess strength to the wrong side of the felt. The upper layer 20 'is located only in zone C, and the wires 1, 2, 3, 4 run together in the plane c (m-p = 1). Each warp yarn 1, 2, 3, 4 passes periodically first over two weft yarns and then under two weft yarns. Yarns 1-4 end at the end of zone C.

The warp yarns 5, 6, 7, 8 running between the two planes a, b in zone A form the lower layer 21 in zone B as a single layer in plane a, and the lower layer 22 in zone C also as a single layer in plane a (q = 1). The yarns 5, 6, 7, 8 pass periodically first under the two weft yarns and then over the two weft yarns.

In zone D, the yarns 5 and 7 form two loops, while the yarns 6 and 8 are folded immediately against the weft yarn and without forming loops. The wires 5-8 form the upper layer 22 'in zone C running in two planes b and c (m-q = 2); they pass first under one weft yarn in plane b, then over two weft yarns in plane c.

In zone B, the yarns 5-8 form an upper layer 21 'running in the plane b.

They pass periodically over one weft yarn, then under three weft yarns, etc., and finally go out to the wrong side, where they are cut in succession.

Thus, the weft level b of zone C is common to the lower layer 20 of the first group G1 and to the upper layer 22 'of the second group G2.

In zone B, the weft plane b is common to the layer formed by the yarns of group G1 and to the upper layer 21 'formed by the yarns of group G2.

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It is obvious that if there were four Kudeta bogs in zone C, a zone C could be added between zones B and C with three tissue levels resembling zone C in Figure 2.

Each sub-weave comprises two groups G1, G2, but there could be three or more of them.

In order for the stresses to be appropriately distributed in zone C, it is recommended that groups G1 and G2 have the same number of wires.

To implement the splice zone BCD at each end of the felt, one can either start from a felt with both ends like zone A, where the yarns are formed in zones B and C in a loom (a machine that re-weaves the fabric in a direction perpendicular to the original weaving direction).

At the beginning of the felt weave:

Yarns 1-4, (Figure 3): - fabric in one weave plane - fabric in one weave plane (layer 20 ') - fabric in two weaves (zones C and B) - finally fabric A.

Yarns 5-8, (Fig. 4): - fabric in two planes (layer 22 ') and layer 21' after transformation.

- fabric in one plane (layers 22 and 21) - finally fabric A.

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At the end of the felt (symmetrical with the beginning) weave:

Yarns 1-4, (Fig. 5): - fabric in two running planes - fabric in one plane

Yarns 5-8, (Figure 6): - fabric in one plane (zones B and C) - fabric in two planes (zone C upper layer and zone B)

Figure 7 shows a woven felt with no excess strength in zone C near the loops (m = n).

Warp yarns 5 to 8 are cut at the end of zone C.

Loops have been made from 50 percent warp yarns, but it would be possible to further increase the loop density.

The blanket (zone A) comprises three tissue levels a, b, c, and zone C resembles the corresponding zone in Figure 2 (m = n = 3). The yarns of the group G1 form the lower layer 20 in two planes (p = 2) and the upper layer 20 'in one plane (m-p = 1).

The yarns of the group G2 form the lower layer 22 in one plane (q = 1) and the upper layer 22 'in two planes (m-q = 2).

In zone B, the yarns of group G1 form a lower layer 23 in two planes and an upper layer 23 'in one plane. The yarns of group G2 form a single layer in three planes like felt A.

Figures 2 and 7 show only one end of the felt, but it is clear that the other end is constructed in the same way so that the loop zones are best suited for connecting the felt.

Claims (6)

8,781 39 A woven felt consisting of n weave layers (a, b) and intended specifically for use in the paper industry, comprising weft yarns (17) and warp yarns (1, 2, 3, 4, 5, 6, 7, 8) having ends folded and pressed down, and said blanket further comprising loops (14) in connection with the folds (15) for joining the felt together and formed in the zone adjacent to the folds (C) m of a weft plane (a, b, c), characterized in that the zone adjacent to the fold (15) (C) comprises, for each subwarp formed by the warp yarns, a first group (G1) of warp yarns (1, 2, 3, 4) forming a lower layer (20) (m> p> 1) comprising a weave plane, and an upper layer (20 ') printed on a lower layer (20) having a mp weave level and a second group (W2) of warp yarns (5, 6, 7, 8) forming a lower layer (22) comprising a w weave level (l <q <p) and an upper layer (22 ') printed on the lower layer (22) and comprising a mq weft plane, in addition to which at least e the warp yarns (1, 3, 5, 7) form loops (14) at the fold (15). Woven felt according to Claim 1, characterized in that the zone (C) adjacent to the folds (15) is thicker than the actual felt (A) without weaving (m> n). Woven felt according to Claim 2, characterized in that p is chosen to be equal to n, where n> 1. Woven felt according to claim 3, characterized in that it comprises a zone (B) which is - adjacent to the felt (A) without overweaving, and in which the first warp yarn group (G1) forms only a lower layer and in which the second warp yarn group (G2) has a lower the layer (21) comprises r weft planes, while the upper layer 9 781 39 (21 ') comprises nr weft planes, the yarns of the second group (G2) terminating in this zone (B). The woven felt according to claim 1, characterized in that n is greater than 2 and in that the zone (C) adjacent to the folds has the same thickness as the felt (A) without weaving (m = n). Woven felt according to one of the preceding claims, characterized in that each group (G1, G2) comprises the same number of warp yarns.