ES2333225T3 - INDICATION OF THE LEVEL OF WEAR OF A FABRIC THROUGH THE USE OF FILAMENTS. - Google Patents

Abstract

The invention relates to wear level indicating filaments and the fabrics made thereof. Disclosed are filaments with multiple layers surrounding a core yarn, where the core and layers are distinguishable from one another so as to indicate fabric wear. Also disclosed are conductive monofilaments used to detect fabric wear, multilayer filaments used to create a guideline on a fabric, and a conductive monofilament that also has a contrasting color used to form a fabric guideline.

Description

Indication of the level of wear of a fabric through the use of filaments.

Field of the Invention

The present invention is directed to the media to detect the level of wear of papermaking and of other industrial fabrics, particularly towards the filaments of multiple layers and conductive filaments as such means. TO through document US-5617903 the multi-layer monofilament.

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Background of the invention

During the papermaking process, it it forms a cellulosic fibrous membrane by deposition of a fibrous pulp that is an aqueous dispersion of cellulose fibers on a mobile training fabric in the training section of A paper machine. The drainage of a large amount of water from the liquid sludge through the formation tissue, depositing the cellulosic fiber membrane on the surface of The training cloth.

The newly formed cellulosic fiber membrane advances from the training section to a pressing section, the which includes a series of pressing rollers. Fibrous membrane cellulosic passes through the pressing rollers supported by a pressing fabric, or as is often the case, between two of such pressing fabrics. In the pressing rollers, the cellulosic fibrous membrane is subjected to compression forces, which squeeze water from them, and adhere the fibers cellulose in the membrane with each other, to convert the membrane Fibrous cellulosic on a sheet of paper. The water is accepted by the press fabric or fabrics, and ideally does not return to the sheet of paper.

The sheet of paper finally advances to a section drying, which includes at least one series of drums or rotary drying cylinders, which are heated internally by steam. The newly formed sheet of paper advances to a path of a coil sequentially around each of the series of drums by means of a drying cloth, which retains the sheet of paper intimately against the surfaces of the drums. Heated drums reduce the water content of the sheet paper to a desirable level through evaporation.

It will be noted that the training fabrics, pressing and drying take the form of endless loops on  the paper machine, and they work the same way as some conveyors It will also be noted that papermaking It is a continuous process which advances at speeds considerable. That is, the fibrous mud is depositing continuously on the training cloth in the training section, while the newly made sheet of paper is winding continuously on rollers after leaving the section of dried

In operation in the form of endless loops about paper machines, papermaking fabrics, and particularly on their interior surfaces, they are susceptible to abrasion wear. A large part of this wear leads to on contact with the stationery components of the machine paper. Finally, many fabrics have to be removed from the paper machines when wear caused by such contact of the movement has reduced the thickness of the fabric, at least by certain locations, to the point where it weakens or has lost certain quality or the characteristic desired by the paper manufacturers in this particular application.

Normally, wear is monitored using a thickness gauge. However, it is difficult to measure the papermaking fabric thickness in a value greater than more than one or two feet (30.48 cm or 60.96 cm) from its edges with said caliber, especially when the fabric is in operation On a paper machine.

It would be very valuable for papermaking technicians that wear could be monitored on a papermaking fabric, and particularly at any point on its internal and external surfaces, even when the paper machine was in operation. The present invention provides said means for industrial
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Summary of the invention

It is therefore a main object of the invention providing an industrial fabric that has a mechanism built-in that allows to monitor the wear of the cloth.

This and other objects and advantages are provided by the present invention. In this regard, the present invention is directed towards a fabric that includes filaments of multiple layers comprising a core thread surrounded by one or More outer layers. The core and layers are visibly distinguishable from each other, for example, by contrast color, or for reflectivity. This allows the wear of the fabric to  be monitored as the abrasion gradually wears the successive layers of the filaments, eventually revealing the core threads.

Brief description of the drawings

Thus, and by the present invention, they will realize their objects and advantages, whose description will be taken in conjunction with the drawings of the same, where:

Figure 1 is a cross-sectional view. of an example of a multilayer filament according to the present invention;

Figure 2 are side and top views of the multilayer filament in Figure 1 showing the wear, incorporating the conclusions of this invention;

Figure 3 is a cross-sectional view. of an example of a multilayer optical filament according to another aspect of the invention;

Figure 4 is a top view of an example of a fabric comprising the multilayer filaments of the figures 1 2 and 3;

Figure 5 is a top view of the fabric of Figure 4, which shows wear.

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Detailed description of the preferred embodiments

A preferred embodiment of the present invention will be described in the context of the filaments and fabrics tissues and used in papermaking. However, it you will notice that the invention is applicable to fabrics used in other industrial configurations where the wear detection and guidance.

Fabric constructions include fabrics interlaced, spiral yarn, knitted, extruded mesh, winding in spiral, and other non-spun fabrics. These fabrics may include also the monofilament threads, folded monofilament, multifilament or multifilament threads folded, and may be of a single layer undulation, a multilayer undulation or laminated When the fabric is one of the spiral winding type, the filament can be the coils, the wires used to connect the coils or inserts (warp fill) that may be present in the internal empty space of the coil. The threads are typically extruded from any of the resins synthetic polymers, such as polyamide and resins of polyester, used for this purpose by specialized technicians ordinary in the techniques of industrial fabrics.

An example of the multilayer filament 10 of the The present invention is illustrated in Figure 1 (seen in section cross). The filament 10 may comprise, for example, a thread of core 12 surrounded by a plurality of outer layers 14, 16, 18. Advantageously, the core 12 and the peripheral layers 14, 16, 18 they are visibly distinguishable from each other, for example by their contrast color, or its reflectivity. This allows me to monitor the wear of the fabrics that make up such filaments 10, as the abrasion gradually wears the successive layers 14, 16, 18 of filaments 10, eventually revealing the threads core 12. An example of multilayer filament 10 showing said wear is shown in figure 2 (section view transversal and plan view).

In alternative embodiments (not shown) core 12 and layers 14, 16, 18 can also be doped with dyes or other substances that will change their appearance. The dye it would then be detectable by a sensor when excited with a external power source, for example, a light (for example, laser or UV) or ultrasound.

In another additional embodiment, the filaments 10 they can also comprise an absorption / transmission core 12 of light, and several transparent layers 14, 16, 18 that have refractions variables n1, n2, n3. An example of this multilayer optical filament shown in figure 3. In this case, the light transmitted / reflected from filament 10 changes color depending of wear level through layers 14, 16, 18.

Figure 4 is a plan view of a fabric unused 20 (wear side) comprising at least some of the multilayer filaments 10, according to the conclusions of the present invention The fabric 20 can be a spun structure of the threads 10 located in a direction transverse to the machine (CD) and by means of wires 2 located in the machine direction (MD), although they do not need to be knitted so that they fall within the reach of the present invention, and could be a nonwoven structure. In the Figure 4, the CD 10 threads that are multilayer filaments of the variety shown in figures 1, 2 and 3 are represented as fabrics with MD 22 threads in a flat wave. In the example shown, the joints 24 on the surface of the fabric 20 are more susceptible to wear because they are formed where a thread in one direction of the fabric 20 passes or crosses over a thread in the other direction, and therefore are high points on the surface of the fabric 20.

After the fabric 20 has been used for a certain period of time, the same plan view of the Fabric 20 will appear as shown in Figure 5. At least one or more than the outer layers 16, 18 of the filaments 10 CD are show as worn to the point where an inner layer 14 or core 12 is exposed to view. Under its distinct color or reflectivity, for example, compared to that of others layers 16, 18, inner layer 14 or core 12 provide a indication of fabric wear 20.

Consequently, by the present invention they carry out their objects and their advantages, and although the preferred embodiments in detail, its scope and objects should not be limited to them; instead, its scope should be determined by that of the appended claims.

Claims (9)

1. A multilayer monofilament, where the mentioned monofilament (10) has a core (12) surrounded by a plurality of the respective layers (11, 16, 18) distinguishable visibly with each other and the core (12) for its contrasting color or reflectivity to indicate a level of wear of a fabric (20) of paper making 2. The monofilament of claim 1, in where the indicated level of fabric wear is associated with a level of wear across the respective layers (14, 16, 18). 3. The monofilament of claim 1 or 2, comprising a light absorption core (12) and / or a core e light transmission and transparent layers (14, 16, 18) that They have variable refractions. 4. The monofilament of claim 3, in where the light reflected or transmitted from the core (12) changes from color, depending on the level of wear across the layers transparent (14, 16, 18). 5. The monofilament of any of the claims 1 to 4, wherein one or more of the cores (12) and of The respective layers (14, 16, 18) are doped with dyes. 6. The monofilament of claim 5, in where the dye is detectable by a sensor when excited by An external energy source. 7. The monofilament of any of the claims 1 to 6, wherein the monofilament (10) has a round or non-round shape 8. The monofilament of any of the claims 1 to 7, wherein the monofilament (10) comprises some or all of the multifilament threads. 9. A fabric for papermaking (20) comprising one or more of the multilayer filaments (10) of any of claims 1 to 8.