Water-blocked fiber optic ribbon cable
AssigneeSumitomo Electric Lightware Corp.
InventorsPatrick S. VanVickle, Scott M. Chastain, Stephen R. Stokes, Scott Alan McCreary
Life of this patent
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Abstract
A water-tight fiber optic ribbon communications cable constructed without the use of gel or grease in the buffer tube(s) thereof. A plurality of water-blocking yarns are provided around at least a portion of the stack of fiber optic ribbons loosely positioned within the buffer tube(s) that possess water swellable characteristics. The swell capacity of the plurality of water blocking yarns exceeds the critical mass of water that could enter the buffer tube(s) by a factor of 2.0 or more. Optionally, superabsorbent powder can be applied between and/or on the fiber optic ribbon stack.
Claims22
An optical fiber loose tube cable, comprising:
- (a) a plurality of stacked fiber optic ribbons or subunits;
- (b) a plurality of water blocking yarns extending generally along the length of said stack of fiber optic ribbons and positioned around at least a portion of the circumference of said stack of fiber optic ribbons, said plurality of water blocking yarns possessing water swellable characteristics;
- (c) a buffer tube having an interior channel larger than said stack of fiber optic ribbons, with said stack of fiber optic ribbons and said plurality of water blocking yarns loosely disposed in said buffer tube;
- (d) wherein the swell capacity (Mcapacity) of said plurality of water blocking yarns exceeds the critical mass of water (Mcritical) that could enter said buffer tube by a factor of 2.0 or more, said swell capacity being determined by the formula:
- Mcapacity=(N)(d)(B)
- wherein
- N=number of water blocking yarns
- d=yarn denier
- B=absorbency
- and said critical mass of water being determined by the formula:
- Mcritical=(Atubeopen)(ρwater)
- wherein
- Atubeopen=open area of buffer tube
- ρwater=density of water.
An optical fiber loose tube cable, comprising:
- (a) a plurality of stacked fiber optic ribbons, said stack of fiber optic ribbons having a superabsorbent powder applied between and/or on said stack of fiber optic ribbons;
- (b) a plurality of water blocking yarns extending generally along the length of said stack of fiber optic ribbons and positioned around at least a portion of the circumference of said stack of fiber optic ribbons, said plurality of water blocking yarns possessing water swellable characteristics;
- (c) a buffer tube having an interior channel larger than said stack of fiber optic ribbons, with said stack of fiber optic ribbons and said plurality of water blocking yarns loosely disposed in said buffer tube;
- (d) wherein the swell capacity (M capacity) of said plurality of water blocking yarns exceeds the critical mass of water (M critical) that could enter said buffer tube by a factor of 2.0 or more, said swell capacity being determined by the formula:
- Mcapacity=(N)(d)(B)
- wherein
- N=number of water blocking yarns
- d=yarn denier
- B=absorbency
- and said critical mass of water being determined by the formula:
- Mcritical=(Atubeopen)(ρwater)
- wherein
- Atubeopen=open area of buffer tube
- ρwater=density of water.
Dependencies are inferred from the claim text.