JPS602793A - Composite spiral dryer cloth and belt produced thereby - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to paper machine fabrics, and in particular to dryer fabrics advantageously used in the dryer section of paper machines, and belts made using the same. , as well as forming wires.

Composite helical structures have been used in conveyor belts made of metal. For example, 32. of the catalog "Cambrizzo Conveyor Peltz" published in 1941 by Cambridge Cross Canno and Knee in Cambridge, Maryland.
See pages 33, 36, 39°68, 69 and 73. See also US Pat. No. 2.9'78,023.

Composite helical shapes made using metal wires are used as conveyors in the manufacturing and gunning industries, and in these applications the main interest is simply in providing a flexible belt that can withstand high temperature environments. be. The present invention
It involves the use of polymeric monofilaments for specific complex helical shapes with selected contour geometries and parameters to obtain the appropriate structure for paper machine forming wires and dryer fabrics. Regarding forming wire and dryer felt fabrics and their use in paper machines, see, for example, European Patent Application No. 80301213.7 (Publication 001
8200).

In summary, prior art spiral dryer fabrics currently used in papermaking machines simply connect interwoven left-handed and right-handed helices by straight connecting bins. Although the present invention uses the same three elements, the connection method is different. The connection arrangement described below eliminates two major deficiencies of currently used spiral dryer fabrics (i.e., relatively high air permeability and relatively few paper contact points per unit area); This is a significant reduction.

The present invention relates to a composite helical fabric useful as a forming wire in a paper machine or as a dryer felt in a paper machine; a plurality of second monofilament yarns in the form of a plurality of right-handed helices; a left-handed helical yarn having parallel axes with said left-handed and right-handed helices lying in the same plane; adjacent right-handed helical yarns alternate; said left-handed and right-handed helices being positioned within each helix and parallel to the axis of the helical yarn; at least three bins: said left-handed helical monofilaments are hinged to each other by non-adjacent bins; said right-handed helical monofilaments are hinged to each other by non-adjacent pins; and adjacent It is characterized by the left-handed and right-handed yarns that touch each other and are offset in the length direction of the fabric.

The fabrics of the present invention, when made endless, are useful as forming wires and dryer belts when installed on paper machines.

FIG. 1 is a perspective view of an endless belt 8 of the present invention made of a fabric 10 of the present invention. The belt 8 is made of flat cloth 10
It can be made endless by interlocking the free end helices of the belt and inserting two bottles to create a self-seam (i.e. a seam of the same construction as the rest of the belt).

FIG. 2 is an enlarged view of a part of the cloth 1o used to make the two-piece belt shown in FIG. 1.

Fabric 10 includes a plurality of individual and discrete helices, such as helices 1, 2, and 3, of monofilament yarn of synthetic polymer resin interspersed with each other. Helices 1, 2 and 3 are identical in size and outline except that when one is a left- or right-handed helix, the adjacent helix is wound in the opposite direction. These helices extend along respective axes of the belt 8 in the cross-machine direction.

Adjacent helices are hinged by a plurality of cross-machine bins 18.

Bottles 18 are preferably made of monofilaments of synthetic polymer resin, and these resins may be the same as or different from the helical monofilaments. Spiral 1-3
And which monofilament is better for making bottle 18, polyolefin? It is a monofilament of thermoplastic synthetic polymer resin such as Lyamide, preferably polyester.

FIG. 3 is a sectional view taken along arrow 3-3 in FIG.
3 shows in more detail the interconnection between helices 1 to 3 according to FIG. This method of interconnection is the essence of the invention and is clearly illustrated in FIG. 4, which shows the interconnection viewed from a direction perpendicular to the longitudinal axis. As shown in FIG. 4, each helical coil contains three bins 18 within the coil, and each segment of each helix is offset from the adjacent helix by approximately 1/3 of the helical width. There is.

The surface pattern obtained on the fabric 10 resembles a twill weave in a ruffled woven fabric. The shape is not limited to 3 bottles per coil, but coils of suitable dimensions, 4 or 5 bottles per coil can also be implemented, which is advantageous. According to the above-described compound helical connection method, a fabric having a greater number of helices per unit length of the belt can be obtained than that obtained by the currently widely used one-coil, two-pin method. The assembly arrangement described above thus creates a less open surface on the fabric 10 and is characterized by a series of interlocking V-shaped patterns.

This composite fabric 10 improves on prior art spiral dryer fabrics for two reasons: it has a much lower permeability and it greatly increases the number of paper contact points per unit area. There is. These advantages were demonstrated by the composite helical fabric assembly described above.

The following examples are illustrative of methods and processes for making and using the invention, and are intended to describe the best mode of carrying out the invention.

Air permeability measurements were made using a Frazier apparatus at a pressure differential of 12.7 m (0.5 in) of H2O.

Example 1 A composite spiral dryer fabric as described above was assembled using polyester monofilament spiral coils and bottles. The diameter of the coil filament is 0.70 (0.02
8 inches) and the diameter of the bottle is 0.90 wm (0
,035 inches). The overall dimensions of the coil are 7.2
6 van (0,286 inches) x 3.63mm (
The coils were wound so that adjacent coils were in contact with each other. Open-wound coils of a specific, predetermined pitch (coil-to-coil distance) facilitate assembly and are used in the preferred embodiment.

This assembly contains three bottles in each helix, and adjacent helices are arranged so that they touch, reverse wind and unwind, and alternate by about 1/3 of their length as shown in FIG. It is assembled so that it can shift.

The test results for the physical properties of this fabric are shown in Table 1.

Example 2 This is not an example of the present invention, but is included for comparison purposes.

The spiral dryer fabric was assembled as in Example 1 above, but with only two bins in each spiral, so that adjacent spirals were offset from each other by the distance between adjacent bins along the length of the fabric. The points are different. The physical properties of this fabric are also shown in Table 1.

Table 1 Fabric of Example 2 (Control) Fabric of Example 1 Air permeability at 0.5 inch H20 993 486 (f t5/min/f t2) (oV/ft2) 3.97 6.12 Area density contributed by helix Part (g-) 1045 1563 It is clearly demonstrated that the fabric of the present invention reduces air permeability by a factor of 51. This reduction in air permeability is an important advantage because it increases the number of dryer locations and paper machines in which spiral fabrics can be used.

This reduction in transmittance is 1213 g/m2 (3
, 97 oV/ft2) to 1870 g/m of the fabric of Example 1.
This was achieved by increasing the weight by up to 2 (6.12 oz/ft2). However, most of the weight gain is in the material on the surface of the fabric, increasing the fibers per unit area and thus absorbing wear and abrasion. The number of paper contact points per unit area is also increased significantly, approximately by a factor of two, providing a significant potential paper quality advantage.

The relatively high transmittance of prior art spiral fabrics is a well-known deficiency. A current method to reduce transmittance is to insert a stuffer big inside the helix. However, the stuffer big is essentially dead weight and merely functions as a transmittance reducing element. In contrast, the 79 mm increase in weight of the composite helical fabric of the present invention is entirely a result of the functional component, ie, the increase in the number of helices per unit area.

Many variations of the preferred embodiments described above may be devised by those skilled in the art without departing from the spirit and scope of the invention. For example, the material of the present invention can be heat set after conventional techniques to achieve dimensional stability. The heat set is
It also helps to reduce stress in the fabric structure due to distortions caused during assembly of apparently incompatible helices.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an example of a composite spiral dryer belt of the present invention, FIG. 2 is an enlarged view of a part of the fabric making up the belt in FIG. 1, and FIG. This is a sectional view taken along line 3-3 in FIG. 2, and FIG. 4 is a diagram showing connections between helical components of the cloth shown in FIG. 2. 1.2.3... Spiral monofilament yarn, 8...
・Endless belt, 10... cloth, 18... bottle. 3rd 1000th Figure ℃10

Claims (1)

Claims: 1. A composite helical paper machine fabric useful as a forming wire in a paper machine and in dryer felts in a dryer section, comprising: a plurality of first monofilaments in the form of a plurality of left-handed helices; a plurality of second monofilament yarns in the form of a plurality of right-handed helices; a left-handed helical yarn having parallel axes with said left-handed and right-handed helices lying in the same plane; and adjacent right-handed helical threads alternating; said left-hand and right-handed helices being positioned within each helix within the helical threads and parallel to the axis of the helical threads; at least three pins; said left-handed helical monofilaments are hinged to each other by non-adjacent pins; said right-handed helix K;
A fabric characterized in that the monofilaments are hinged to each other by non-adjacent pins; and adjacent left-handed and right-handed yarns are in contact with each other and are offset along the length of the fabric. 2. The fabric according to claim 1, wherein the monofilament is polyester. 3. The fabric according to claim 1, wherein the pin is made of polyester. 4. The above spiral is 7.26 inches (0,286 inches)
2. The fabric of claim 1, having a flat oval cross-section with overall dimensions of 0.143 inches. 5. The fabric according to claim 1, which is formed into an endless belt.