Water-blocked optical fiber communications cable
First Claim
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1. An optical fiber cable, which comprises:
- a core comprising a longitudinally extending central strength member, and at least one generally longitudinally extending buffer tube comprising at least one optical fiber, said buffer tube being positioned around at least a portion of the circumference of said central strength member;
a jacket enclosing said core; and
a water-blocking system disposed between said central strength member of said core and said jacket, said water-blocking system comprising at least one yarn possessing water swellable characteristics and extending generally longitudinally along the length of said central strength member, and a protective layer possessing water swellable characteristics positioned between said core and said jacket and extending around said buffer tube and longitudinally along the length thereof;
whereby interstices within said core are substantially filled when water comes into contact with said water-blocking system so as to prevent water passage longitudinally along the cable.
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Abstract
A water-tight optical fiber communications cable constructed without the use of a viscous water-blocking compound other than in the buffer tubes thereof. One or more water swellable yarns are helically wrapped around the central strength member to absorb any water which may be present in the interstices between the central strength member and the buffer tubes. Additionally, a water swellable tape is disposed between the core and the jacket of the cable to absorb water from the interstices between the buffer tubes and elements overlaying the core of the cable.
65 Citations
33 Claims
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1. An optical fiber cable, which comprises:
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a core comprising a longitudinally extending central strength member, and at least one generally longitudinally extending buffer tube comprising at least one optical fiber, said buffer tube being positioned around at least a portion of the circumference of said central strength member; a jacket enclosing said core; and a water-blocking system disposed between said central strength member of said core and said jacket, said water-blocking system comprising at least one yarn possessing water swellable characteristics and extending generally longitudinally along the length of said central strength member, and a protective layer possessing water swellable characteristics positioned between said core and said jacket and extending around said buffer tube and longitudinally along the length thereof; whereby interstices within said core are substantially filled when water comes into contact with said water-blocking system so as to prevent water passage longitudinally along the cable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An optical fiber cable, which comprises:
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a core comprising a longitudinally extending central strength member, and a plurality of generally longitudinally extending buffer tubes each comprising at least one optical fiber, said buffer tubes being positioned around at least a portion of the circumference of said central strength member; a jacket enclosing said core; a water-blocking system disposed between said central strength member of said core and said jacket, said water-blocking system comprising at least one yarn possessing water swellable characteristics helically wrapped around said central strength member and extending longitudinally along the length thereof, and a protective layer possessing water swellable characteristics positioned between said core and said jacket and extending around said plurality of buffer tubes and longitudinally along the length thereof; and a layer of strength members positioned between said water-blocking system and said jacket, said strength members extending generally longitudinally along the length of the cable; whereby interstices within said core are substantially filled when water comes into contact with said water-blocking system so as to prevent water passage longitudinally along the cable. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification