APPLICATOR HEAD FOR AN OPTICAL FIBER WITH REDUCED WETTING LENGTH Russian patent published in 2021 - IPC C03C25/18 

FIELD: applying fluent materials.

SUBSTANCE: invention relates to an apparatus and a method of applying coating to a glass fiber and provides a more stable and reliable coating-applying process at a fiber drawing speed of 50 m/s or more leading to production of strictly concentric coatings with uniform thickness. The apparatus for optical fiber coating comprises a purely conical applicator head with a conical inlet section with a tapered wall with a half angle α, wherein 2°≤α≤25° and the height of the cone L₁ of less than 2.2 mm, and a cylindrical section with internal diameter d₂ of 0.1 mm ≤ d₂ ≤ 0.5 mm and the height of the cylinder L₂ wherein 0.05 mm ≤L₂≤ 1.25 mm. A guiding head is located above the purely conical applicator head so that the wetting length (L₅) between the optical fiber outlet from the guiding head and the inlet to the purely conical applicator head is 1 to 5 mm. The apparatus comprises a holder for fixing the purely conical applicator head and the guide head at a preset correlation providing a coating chamber with an inner radius L₆ measured from the optical fiber axis to the inner wall of the holder from 3 to 10 mm. To apply several coatings up to 50 microns in thickness, the proposed apparatuses can be installed in series.

EFFECT: technical result is more stable and reliable coating-applying process at a fiber drawing speed of 50 m/s or more leading to production of strictly concentric coatings with uniform thickness.

23 cl, 17 dwg