Abstract: An apparatus and method for sealing the top of an optical waveguide draw furnace is disclosed. The apparatus includes an assembly constructed and arranged to removably cover the top of the draw furnace while mating with the downfeed handle. The apparatus includes an elongated sleeve having a base and a sealing mechanism positioned on the sleeve at a location remote from the base. The sleeve defines a chamber for receiving the downfeed handle, and the sealing mechanism is arranged with respect to the sleeve to mate with the downfeed handle received in the chamber. In one aspect of the invention, the apparatus further includes an inert gas purge for providing an inert atmosphere within the chamber. A method of sealing the top of an optical waveguide draw furnace is also disclosed.

Abstract: An apparatus and method for sealing the bottom of an optical waveguide draw furnace is disclosed. The apparatus includes an assembly constructed and arranged to mate with the bottom of the draw furnace to form a seal, and a leak detection system communicating with the assembly to signal the forming of a proper or an improper seal. The covering plate of the assembly is selectively seated on the sealing plate of the draw furnace to form the seal, and an inert gas is delivered between the covering plate and the bottom of the draw furnace. The flow of the inert gas is detected to determine if the seal has been properly formed. An assembly including a covering plate having at least two radially spaced gaskets circumferentially positioned on the top surface of the covering plate for engagement with the sealing plate at the bottom of the draw furnace, and a method for sealing the bottom of a draw furnace are also disclosed.