FI96705C - Absorbatorfilt - Google Patents

Abstract

A papermaker's felt (28) having a dual layer base with a high absorption capacity with a weave pattern having twice as many machine direction yarns on the top side (25) of the fabric as compared to the bottom side (26) of the fabric. The yarns may be spun yarns, multi-filaments, monofilaments, core-wrapped yarns and any kind of twists. Treated and extruded yarns may also be used. The base fabric is attached to a top fabric (27) by needling. <IMAGE>

Description

96705

ABSORPTION FELT - ABSORBENT FILTER

The present invention relates to felts used in papermaking machines, and more particularly to felts for removing water from a sheet of paper as the felt supports and transports the sheet.

To date, a variety of techniques have been used to remove water from a sheet of paper. The most common technique is to use a press, in which a sheet of paper and the blanket on which it is transported are pressed between rollers. In this case, the felt is formed in such a way that the water leaving the paper passes through the felt and leaves.

15

The compression felts are preferably woven with relatively large open areas or air spaces that promote their water transport capacity so that water is removed from the felt as it is passed over the suction box. The press felt is usually belt-shaped and during the various operations mentioned above, large amounts of water accumulate in the press felt and are removed by suction or other drying devices, usually after the paper web and the press felt are no longer in direct contact.

25

An ideal papermaking felt should have at least the following properties. First, its surface should be fine enough to produce a smooth mark and minimize the marking of the finished sheet of paper. Second, it should be sufficiently open to allow water to drain through it without significant resistance. Third, it should be flexible enough to recover quickly from large nip presses over a long period of time. Fourth, it should be strong and strong enough to provide good stability, abrasion resistance, and 35 felt life.

It has been found that a paper machine fabric with a high vibration absorption capacity of the base fabric compared to a standard 2 96705 garbage fabric provides better runnability, fewer maintenance stops and better paper quality.

Accordingly, it is an object of the invention to provide a fabric for paper-5 use which has a better vibration absorption capacity.

Another object of the invention is to provide a felt with high elasticity and flexibility to ensure better runnability, fewer maintenance stops, and better paper quality.

It is a further object of the invention to provide a paper machine felt with improved dewatering performance.

15

Yet another object of the invention is to provide a felt with longer lasting flexibility for better wet felt properties at heavily loaded, high speed locations.

These and other objects obvious to a person skilled in the art can be achieved by means of the invention, one embodiment of which is a paper machine felt with a two-layer base fabric woven with a special weave pattern which results in energy-absorbing properties of the base fabric. The yarns are woven into a pattern in which the number of machine direction yarns on the upper surface of the fabric is twice as large as the number of machine direction yarns on the lower surface of the fabric. The yarns can be spun yarns, multifilament yarns, single yarns, yarns wound around a core 30, or any braids. The base fabric is attached to the upper fabric by knitting. The preferred top fabric is a single ply fabric with long runs and fine yarn components.

A felt with an absorbent base fabric according to the invention having a special weft formula has a significantly higher absorption capacity compared to ordinary blankets. High elasticity and flexibility allow for better runnability, 3 96705 den, fewer maintenance stops and better paper quality.

This composition reduces flow resistance, providing better dewatering performance. By using the upper fabric together with the ab-absorption fabric, the requirements of the felt have been adapted to the pape-5 quality (weight, surface area) and the compression conditions (speed, pressure, runnability). In addition to being used as a component of a paper machine felt, the base fabric can also be used as a forming machine for a paper machine.

In another embodiment, the yarns of the base fabric are treated or extruded with elastic resins or polymeric materials having excellent damping properties. The materials include single-stranded yarns or multi / single-stranded braids in the machine direction, which can be treated or extruded with elastic resins (polyurethane, latex, polyacrylic, etc.). An example of a suitable fiber is a thermoplastic polyester elastomer, or TPE. The specially treated yarns are arranged parallel to the machine to provide a paper machine fabric with better vibration damping ability.

In the following, the invention will be explained in detail by means of preferred exemplary embodiments with reference to the accompanying drawings, in which 25

Fig. 1 is a weft diagram illustrating a weft pattern of a base fabric;

Fig. 2 schematically shows the path of the cross-machine direction yarns 30 relative to the machine direction yarns;

Figure 3 schematically shows the path of the cross-machine direction yarns relative to the machine direction yarns, showing the top fabric and the bottom fabric.

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In the first embodiment, the felt consists of a two-layer base fabric 28 woven with a special pattern to improve its damping properties, and an upper fabric 4 96705 27, as shown in Fig. 3. The base fabric 28 may function either as a paper machine forming fabric or, when combined with the top fabric 27, as a paper machine felt. The two-ply base fabric consists of a fabric having groups of either machine-direction yarns or machine-direction yarns in more than one plane; Double layer fabrics are made with two bases to form an endless felt. First, they can be woven by a smooth weaving process, whereby their ends are joined by any of a number of well-known methods for forming an endless belt. Alternatively, they can be woven directly into a continuous belt shape by an endless weaving process. Both methods are well known and the term "endless belt" as used herein refers to belts made by either method. In the Si-15 flat-woven paper machine fabric, the warp yarns extend in the machine direction and the filler yarns in the cross-machine direction. In a paper machine fabric woven endlessly, the warp yarns extend in the cross-machine direction and the filler yarns extend in the machine direction. In this specification, the terms "machine direction" and "cross-machine direction" refer to the respective direction corresponding to the direction of movement of the paper machine fabric in the paper machine and the direction transverse to this direction.

Fig. 1 is a weft diagram illustrating a weft pattern of a fabric of the present invention with six arms. The six horizontal rows of the diagram, numbered 1-6, represent the six cross-machine direction wires. The vertical columns in the diagram, numbered 7-24, represent 18 machine direction yarns. The symbols "X" in the diagram represent the 30 points where the machine direction yarns are woven under the cross machine direction yarns at that point. The symbols "O" in the diagram illustrate the points where the machine direction yarns are woven over the cross machine direction yarns at that point.

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The pattern is repeated for every sixth cross-machine direction yarn and every 18 machine-direction threads. In the various figures • · 5 96705 one weft repeat is marked for 1-6 cross-machine direction yarns and 7-24 cross-machine direction threads.

Figure 2 shows a schematic cross-sectional view 5 of the path of the transverse yarns of the machine of the base fabric according to the invention. It shows six cross-machine direction yarns in one weave pattern and their relative position with respect to the same machine direction yarns.

10 Numbers 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, 22 and 23 refer to machine direction yarns on the upper surface 25 of the fabric 28. Numbers 9, 12, 15, 18, 21 and 24 refer to the machine It is clear that the fabric 28 has twice as many machine direction yarns 15 on the upper surface 25 as there are on the lower surface 26.

Figure 3 shows a cross-sectional view of the fabric 28 together with the upper fabric 27. The upper fabric 27 can be any fabric knitted into the base fabric in a conventional manner. One preferred top fabric is a single ply fabric with long runs and fine yarn components (i.e., 0.2 mm x 2 ply or 0.15 mm x 3 ply, etc.). When the weft formula of the invention is used, an increase of more than 25% in hysteresis results. The vibration damping properties are tested by measuring the elasticity coefficient and arranging hysteresis in the load tester. The damping properties depend on the flexibility of the base fabric 28 or the combination of the base fabric 28 and the top fabric 27.

Another embodiment involves the use of yarns in the machine direction, which yarns have been treated or extruded with elastic resins or polymers. Preferred materials include single strand yarns or multi / single strand braids in the machine direction that can be treated or extruded with elastic resins such as polyurethane, latex, polyacrylic, etc. The use of such materials provides an improvement in hysteresis values.

• »6 96705

An example of a suitable fiber is a "thermoplastic polyester-elastomer" or TPE. For example, the wire may be a 0.020 inch diameter "Riteflex" manufactured by Hoechest Celanese. Thermoplastic polyester elastomer pi-5 should be available from the manufacturer in a single strand diameter of 0.004 to 0.060 inches. This material can also be used in multifilament form. Other polymers with energy absorbing properties are also available.

The invention may be practiced in other specific forms without departing from the spirit or essential characteristics thereof. Thus, the disclosed embodiments are to be considered as illustrative only and not restrictive. The invention is thus not limited to the above-mentioned exemplary embodiments, but can be varied within the scope of the appended claims.

Claims (2)

1. Blanket for a paper machine, consisting of a six-shaft double-layered woven base cloth (28), in which samples are woven into trees 5 (1,2,3,4,5,6) running in the transverse direction and trees of the machine (7,6,8 , 9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24) running in the longitudinal direction of the machine, characterized in that in a first shaft a transverse tree ( 1) running under a 10 longitudinal tree (7), over two longitudinal trees (8,9), under two longitudinal trees (10,11), over a longitudinal tree (12), under five longitudinal trees (13 ... 17 ), over a longitudinal tree (18), under two longitudinal trees (19,20), over two longitudinal trees (21,22), under a longitudinal tree (23) and over a longitudinal tree (24); that in a second shaft a transverse tree (2) runs under two longitudinal trees (7,8), over a longitudinal tree (9), under five longitudinal trees (10 ... 14), over a longitudinal tree 20 (15) , under two longitudinal trees (16,17), over two longitudinal trees (18,19), under a longitudinal tree (20), over a longitudinal tree (21), under a longitudinal tree (22) and over two longitudinal trees (23,24); In a third shaft, a transverse tree (3) runs under five longitudinal trees (7 ... 11), over a longitudinal tree (12), under two longitudinal trees (13,14), over a longitudinal tree (15). 16), under a longitudinal tree (17), over a longitudinal tree (18), under a longitudinal tree (19), over two longitudinal trees (20,21), under two longitudinal trees (22,23) and under a longitudinal trees (24); that in a fourth shaft a transverse tree (4) runs over a longitudinal tree (7), under a longitudinal tree (8), over a longitudinal tree (9), under a longitudinal tree (10), over 13 longitudinal tree trees (11,12), under two longitudinal trees (13,14), over a longitudinal tree (15), under five longitudinal trees (16 ... 20), over a longitudinal tree (21), under two longitudinal trees (13) 22.23) and over a longitudinal tree (24); * In a fifth shaft a transverse tree (5) runs under two longitudinal trees (7,8), over two longitudinal trees (9,10), under a longitudinal tree (11), over a longitudinal tree (12), under a longitudinal tree (13), over two longitudinal trees (14,15), under two longitudinal trees (16,17), over a longitudinal tree (18), under five longitudinal trees (19 ... 23) and above a longitudinal tree (24) and, in a giant shaft, a transverse tree (6) running under two longitudinal trees (7,8), over a longitudinal tree (9), under two longitudinal trees (10,11), over two longitudinal trees (12,13), under a longitudinal tree (14), over a longitudinal tree (15), under a longitudinal tree (16), over two longitudinal trees (17,18), under two longitudinal trees (19, 20), 20 over one longitudinal tree (21) and under three longitudinal trees (22 ... 24), which pattern is repeated for every six transverse trees trees and for every eighth longitudinal tree, <25 and the base cloth (28) has an upper surface (25) and a lower surface (26), the number of longitudinal trees in the upper surface being twice as large as the number of longitudinal trees in the lower surface; 30 and in the base cloth is an oven cloth. 2. Hexagonal double-layered woven cloth (28) intended for use in a paper machine, comprising a woven pattern of transversely extending trees (1,2,3,4,5,6) and>. · The trees running longitudinally (7 ... 24) of the machine can be characterized in that in a first shaft a transverse tree (1) runs under a longitudinal tree (7), over two longitudinal trees (8,9 ), under two longitudinal trees (10,11), over a longitudinal tree (12), under five longitudinal trees (13 ... 17), over a longitudinal tree (18), under two longitudinal trees (19,20), over two longitudinal trees (21, 22), under a longitudinal tree (23) and over a longitudinal tree (24); that in a second shaft a transverse tree (2) runs under two longitudinal trees (7,8), over a longitudinal tree (9), under five longitudinal trees (10 ... 14), over a longitudinal tree 15 (15) , under two longitudinal trees (16,17), over two longitudinal trees (18,19), under a longitudinal tree (20), over a longitudinal tree (21), under a longitudinal tree (22) and over two longitudinal trees (23,24); In a third shaft, a transverse tree (3) runs under five longitudinal trees (7 ... 11), over a longitudinal tree (12), under two longitudinal trees (13,14), over a longitudinal tree (15). 16), under a longitudinal tree (17), over a longitudinal tree (18), under a longitudinal tree (19), over two longitudinal trees (20,21), under two longitudinal trees (22,23) and under a longitudinal trees (24); that in a fourth shaft a transverse tree (4) runs over a longitudinal tree (7), under a longitudinal tree (8), over a longitudinal tree (9), under a longitudinal tree (10), over two longitudinal trees ( 11,12), under two longitudinal trees (13,14), over a longitudinal tree (15), under five longitudinal trees (16 ... 20), over a longitudinal tree (21), under two longitudinal trees (22, 23) and over a longitudinal tree (24), -35 «» is 96705 that in a fifth shaft a transverse tree (5) runs under two longitudinal trees (7,8), over two longitudinal trees (9,10), * under a longitudinal tree (11), over a longitudinal tree (12), under a longitudinal tree (13), over two longitudinal trees (14,15), under two longitudinal trees (16,17), over a longitudinal tree (11). 18), under five longitudinal trees (19 ... 23) and over a longitudinal tree (24), and to run in a sixth shaft a transverse tree (6) r under two longitudinal trees (7,8), over a longitudinal tree (9), under two longitudinal trees (10,11), over two longitudinal trees (12,13), under a longitudinal tree (14), over a longitudinal trees (15), under a longitudinal tree (16), over two longitudinal trees (17,18), under two longitudinal trees (19,20), over a longitudinal tree (21) and under three longitudinal trees (22). ..24), which sample is repeated for every six transverse trees and for each eighth longitudinal tree, 20 and the base cloth (28) has an upper surface (25) and a lower surface (26), the number of longitudinal trees in the upper surface being twice as large such as the number of longitudinal trees in the lower surface.