Apparatus and method for use in applying particles to an external layer of uncured resin of a coating of an optical fibre unit

A method of manufacturing an optical fibre assembly for blown installation, comprising providing an optical fibre unit comprising at least one optical fibre having a coating comprising an external layer of uncured resin material, passing said unit through a turbulent flow of fluidised particles provided in an axially extending through-passage having surface means intermediate the axial ends thereof to deflect said particles and thereby generate said turbulent flow and such that some of the particles adhere to said external layer of uncured resin material, and curing said external layer.

Optical fibre particle applying apparatus in which particles are applied to an external layer of uncured resin material of a coating of an optical fibre unit comprising at least one optical fibre, said apparatus comprising means defining a chamber having an axially aligned inlet and outlet through which, in use, such an optical fibre unit is passed, inlet means for admitting a flow of fluidised particles into the chamber and an outlet means for discharging such fluidised particles from the chamber, said chamber defining means being provided with means for directing gas toward the axis of said chamber and into said chamber in the region of said outlet and/or inlet for substantially preventing blockage thereof by such fluidised particles.

A method of manufacturing an optical fibre assembly for blown installation, comprising providing an optical fibre unit comprising at least one optical fibre having a coating comprising an external layer of uncured resin material, providing a flow of fluidised particles in a chamber with an axis, passing said unit successively through an inlet into said chamber and an outlet therefrom such that some of the particles adhere to said external layer of uncured resin material, directing gas toward said axis into said chamber in the region of said outlet and/or inlet for at least substantially preventing said outlet and/or inlet from being blocked by said flow of fluid particles, and curing said external layer.

Optical fibre particle applying apparatus in which particles are applied to an external layer of uncured resin material of a coating of an optical fibre unit comprising at least one optical fibre, said apparatus comprising passage defining means defining an axially extending through-passage through which, in use, such an optical fibre unit is passed, said passage defining means having an inlet for admitting fluidised particles into said through-passage, and said through-passage being provided with a plurality of passage restrictions which are axially spaced in said through-passage and constitute means for generating turbulence in such fluidised particles in said through-passage.

Optical fibre particle applying apparatus in which particles are applied to an external layer of uncured resin material of a coating of an optical fibre unit comprising at least one optical fibre, said apparatus comprising passage defining means defining an axially extending through-passage through which, in use, such an optical fibre unit is passed, said passage defining means having an inlet for admitting fluidised particles into said through-passage, and said through-passage being provided with means for generating turbulence in such fluidised particles in said through-passage, said turbulence generating means comprising at least one auxiliary passage displaced from the axis of said through passage and having an outlet end arranged for discharging fluidised particles into said through-passage.

A method of manufacturing an optical fibre assembly for blown installation, comprising providing a fibre unit comprising at least one optical fibre having a coating comprising an external layer of uncured resin material, passing said unit through a turbulent flow of fluidised particles provided in an axially extending through-passage such that some of the particles adhere to said external layer of uncured resin material, and curing said external layer, wherein said turbulent flow is generated by passing fluidised particles through at least one auxiliary passage and discharging said fluidised particles from the or each auxiliary passage into a flow of fluidised particles in said through-passage.