Cap assembly and optical fiber cooling process

A cap assembly for feeding non-reactant cooling gas selected from the group consisting of helium, nitrogen, carbon dioxide, hydrogen and mixtures thereof and non-reactant sealing gas selected from the group consisting of nitrogen, carbon dioxide, hydrogen, helium, argon, dry air and mixtures thereof to and collecting said non-reactant cooling gas from a heat exchanger device comprising side walls, a fiber inlet end having an opening in its center, a fiber outlet end having an opening in its center, wherein the opening at said fiber inlet end is smaller than the opening at said fiber outlet end and connecting means with a opening in its center which is attached to the fiber outlet end, the side walls having mounted therein port means to allow gas to flow through said side walls, said port means comprising a hollow bore extending radially out from the side walls wherein said port means allows gas to flow into and out of said cap assembly and said cap assembly being generally shaped and sized to be removable from said heat exchange device.