초록 ▼

Hot optical fiber being drawn from a preform is cooled in a helium cooled heat exchanger by a two-stage process. In the first stage, in which the rate of draw of fiber through the heat exchanger is increased to the design draw rate, the rate of flow of helium to the heat exchanger is increased as th

Hot optical fiber being drawn from a preform is cooled in a helium cooled heat exchanger by a two-stage process. In the first stage, in which the rate of draw of fiber through the heat exchanger is increased to the design draw rate, the rate of flow of helium to the heat exchanger is increased as the rate of draw of fiber is increased. Helium is withdrawn from the heat exchanger by a variable speed blower, and during the first stage the rate of withdrawal of helium from the heat exchanger is controlled primarily by the rate of flow of helium into the heat exchanger, and during the second stage, the rate of flow of helium to the heat exchanger is maintained constant and the rate of withdrawal is determined primarily by the pressure in the heat exchanger.

대표청구항 ▼

[ What is claimed is:] [1.] A method of cooling a hot drawn fiber in a heat exchange unit comprising: a single cooling chamber having one fiber inlet opening, one fiber outlet opening, at least one cooling gas inlet and at least one cooling gas outlet; and a variable speed gas blower, comprising the

[ What is claimed is:] [1.] A method of cooling a hot drawn fiber in a heat exchange unit comprising: a single cooling chamber having one fiber inlet opening, one fiber outlet opening, at least one cooling gas inlet and at least one cooling gas outlet; and a variable speed gas blower, comprising the steps:(a) drawing said fiber through said cooling chamber;(b) introducing gaseous coolant into said cooling chamber via said at least one cooling gas inlet; and(c) withdrawing a gaseous exhaust stream comprising said gaseous coolant and at least one gaseous impurity from said cooling chamber by means of said variable speed gas blower at a flow rate such that the pressure in at least part of said at least one cooling chamber is maintained below atmospheric pressure.