Water-resistant cable
First Claim
1. An optical fibre cable comprising a longitudinal cavity extending along the length of the cable, at least one optical fibre housed inside said longitudinal cavity, said longitudinal cavity further comprising a solid and compact element within it, wherein said solid and compact element comprises a water-soluble polymer material which, following accidental ingress of water into the cable, is capable of forming an aqueous solution with a predetermined viscosity such as to block the flow of water within 10 meters of the point of ingress.
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Accused Products
Abstract
The present invention relates to a cable, in particular an optical fiber cable, which is resistant to the radial permeation and to the longitudinal propagation of water. This cable contains a water-soluble polymer material which is a water-swellable and water-soluble material. In particular, this cable is characterized in that, following the ingress of water into this cable, the propagation of water is impeded on account of the combined effect of the swelling of the water-soluble material and the formation of an aqueous solution of said material which has a predetermined viscosity, so as to impede the passage of the residual water. Preferably, the water-soluble material is chosen from polyacrylamide, modified polyvinyl alcohol, vinyl alcohol/vinyl acetate copolymers, polyvinylpyrrolidone, and mixtures thereof, the material preferably being a vinyl alcohol/vinyl acetate copolymer. The material can advantageously be extruded to form tubular elements for containing optical fibers, for example, two-layer tubular elements in which the inner layer is made of water-soluble material and the outer layer is made of a conventional polymer such as PE, PP or PBT.
48 Citations
29 Claims
- 1. An optical fibre cable comprising a longitudinal cavity extending along the length of the cable, at least one optical fibre housed inside said longitudinal cavity, said longitudinal cavity further comprising a solid and compact element within it, wherein said solid and compact element comprises a water-soluble polymer material which, following accidental ingress of water into the cable, is capable of forming an aqueous solution with a predetermined viscosity such as to block the flow of water within 10 meters of the point of ingress.
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18. An optical fibre cable comprising a cavity and a solid and compact element associated with said cavity, wherein said solid and compact element comprises a water-soluble polymer material and wherein, in the presence of a relative humidity of substantially less than or equal to about 80%, the water-soluble polymer material absorbs an amount of water of less than about 25% of the amount of water which can be absorbed by the water-soluble solid material under saturation conditions.
Specification