Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Woven fabric – Including strand which is stated to have specific attributes
Reexamination Certificate
1999-05-24
2001-09-25
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Woven fabric
Including strand which is stated to have specific attributes
C442S185000, C442S198000, C442S229000, C442S238000, C442S246000, C442S301000
Reexamination Certificate
active
06294489
ABSTRACT:
The present invention relates to a conveyor belt designed to be mounted in an installation for conveying articles at high temperature, in particular glass articles raised to temperatures that may be as high as 800° C. or 900° C.
BACKGROUND OF THE INVENTION
In the glass-making industry, during the manufacturing process, glass articles taken to temperatures that may be as high as 800° C. or 900° C. are transported by conveyors having textile belts. These conveyor belts, which are tensioned and are supported by wheels, must be capable firstly of withstanding the traction and bending forces inherent to the mechanical conveyor system, and secondly of withstanding the temperature of the glass articles without giving rise to surface defects thereon.
The conveyor belts that are generally implemented are constituted by asbestos fibers having mechanical and thermal characteristic that enable them to fulfill the above conditions in satisfactory manner.
However, asbestos is known to be toxic and its use is now banned. No other fiber has the same mechanical and thermal characteristics as those shown by asbestos. It is therefore not possible to envisage obtaining a textile conveyor belt that satisfies the same specifications as those given above merely by replacing asbestos fibers with some other kind of fiber.
OBJECTS AND SUMMARY OF THE INVENTION
The object of the present Applicant is to provide a textile conveyor belt that is free from asbestos, that is capable simultaneously of withstanding the traction and bending forces inherent to the mechanical conveyor system commonly used, and that is capable of carrying articles at high temperatures without any risk of marking them, in particular articles made of glass.
This object is achieved by the textile conveyor belt of the invention which is constituted by a textile conveyor belt constituted by at least two layers, namely an outer layer designed to come into contact with articles and an inner layer designed to come into contact with a mechanical conveyor system. In a manner characteristic of the invention, cohesion between the layers is provided by binding threads, the outer layer and the binding threads being made of threads that are made up of an intimate mixture of fibers comprising both stainless steel fibers and fibers of a material selected from those which decompose into carbon when raised to high temperature, and the inner layer being made of threads having good properties concerning both mechanical strength and resistance to temperature.
In the special structure of the conveyor belt of the invention, it is the inner layer which serves mainly to provide mechanical strength to the overall conveyor belt, while it is the outer layer which must withstand the very high temperature, at least via the outside face thereof which comes into contact with the articles being conveyed. The stainless steel fibers need to be intimately mixed with other fibers in order to be capable of being spun under acceptable conditions. In addition, the presence, in the outer layer and in the binding layer, of fibers which decompose into carbon when taken to high temperature, makes it possible to have a surface state which, in co-operation with the stainless steel fibers, avoids marking the articles that are raised to high temperature, and in particular articles made of glass. Thus, contact of articles at high temperature with a surface portion of the outer layer and with the binding threads causes the fibers other than the stainless steel fibers to decompose into carbon. This decomposition has the advantage of providing a surface state that does not cause marking and that does not give rise to any unacceptable drawback insofar as the threads in this surface portion, both in the outer layer and the binding threads, are not subjected to significant mechanical forces since these forces are supported mainly by the inner layer of the conveyor belt.
Preferably, the fibers intimately mixed with the stainless steel and that decompose into carbon are para-aramid fibers, in particular those known under the names Kevlar and Twaron or indeed polybenzimidazole fibers known under the names P.B.I., and Zylon.
Preferably, the threads constituting the outer layer and the binding threads are constituted by a mixture comprising 50% to 90% by weight stainless steel fibers and 50% to 10% by weight fibers that decompose into carbon at high temperature.
Preferably, the threads constituting the inner layer are made from para-aramid fibers.
Advantageously, to increase the dimensional stability of the conveyor belt when faced with the mechanical stresses of the conveyor system, the outer layer and the inner layer are reinforced by reinforcement, e.g. the threads constituting one and/or the other layer in the warp direction and in the weft direction of a woven cloth, are reinforced by a continuous metal filament or any other filament having high mechanical strength and resistance to temperature.
In a preferred embodiment, the conveyor belt of the invention is obtained by multi-ply weaving comprising at least two plies corresponding respectively to the outer layer and to the inner layer.
In this embodiment, the conveyor belt preferably comprises four plies, two outer plies being constituted, as are the binding threads, by an intimate mixture of stainless steel fibers and of aramid fibers, while the third and fourth plies are made of threads obtained from aramid fibers.
Preferably, in this configuration, the four plies are reinforced in warp and in weft by a continuous reinforcing filament which is either made of metal or of a material that has high mechanical strength and good resistance to temperature.
REFERENCES:
patent: 5173361 (1992-12-01), Yamashita et al.
patent: 5399418 (1995-03-01), Hartmanns et al.
patent: 5780152 (1998-07-01), Ichiryu et al.
patent: 5785621 (1998-07-01), Birzele
patent: 38 43 811 (1990-07-01), None
patent: WO9607788A1 (1996-03-01), None
Abstract. JP 62 199842 (Asahi Sekimen), Sep. 3, 1987.
Ferlam Technologies
Morris Terrel
Torres-Velazquez Norca L.
Wolf, Greenfield & Sacks, P. C.
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