that can in turn result in gaseous inclusions in the glass a seal between the inlet and downcomer should be capable of meeting multiple objectives the seal should allow for differential movement of the downcomer from the inlet and forming body the seal components must withstand elevated temperatures adjustability between seal components must be maintained thermal gradients in the molten glass conveying tubes should be minimized the downcomer should be electrically isolated from the inlet and from ground visual access should be maintained for alignment purposes and a gas tight separation between the downcomer inlet tube assemblies and the general environment should be established fig3 depicts an exemplary embodiment of an apparatus 52 for sealing the downcomer to inlet joint the apparatus comprises a bellows 54 downcomer sealing flange 56 and inlet sealing flange 58 the apparatus may also comprise one or more downcomer bellows clamps 60 one or more inlet bellow clamps 62 and electrical insulating material 64 disposed at various positions on or about the sealing apparatus these and other features that address at least some of the objectives above will be described in more detail below fig4 and 5 depict an exemplary sealing flange that may be used as either or both a downcomer sealing flange or an inlet sealing flange although downcomer and inlet sealing flanges 56 58 may differ in size and shape their basic materials and construction are generally identical consequently reference.