METHOD AND APPARATUS FOR SEALING THE BOTTOM OF A FURNACE FORDRAWING OPTICAL FIBRE FROM A PREFORM

摘要

An apparatus and method for sealing the bottom of an optical waveguide draw furnace is disclosed. The apparatus includes an assembly (10) constructed an d arranged to mate with the bottom (70) of the draw furnace (51) to form a sea l, and a leak detection system communicating with the assembly to signal the forming of a proper or an improper seal. The covering plate (12) of the assembly is selectively seated on the sealing plate (72) of the draw furnace (51) to form the seal, and an inert gas is delivered between the covering plate (12) and the bottom (70) of the draw furnace. The flow of the inert ga s is detected to determine if the seal has been properly formed. An assembly (10) including a covering plate (12) having at least two radially spaced gaskets (18, 20) circumferentially positioned on the top surface (14) of the covering plate (12) for engagement with the sealing plate (72) at the bottom (70) of the draw furnace (51), and a method for sealing the bottom of a draw furnace are also disclosed. Sealing the bottom of sucha draw furnace occurs during preform loading and unloading as well as during idle periods, i.e. those periods when no optical fiber is being drawn from the preform.