Abstract: A discharge control device is presented which includes a variable opening formed between two cylinders with parallel axes. The cylinders are mounted between two symmetrical support blocks having bores and are spaced at a distance equal to the sum of their radii. At least one of the cylinders has an external cut-out which, upon rotation of the two cylinders, defines the variable opening. The cylinders are in the form of discs with an axial thickness wherein the cut-out extends over the whole thickness. The discharge control device controls the flow of molten materials.

Abstract: A seal for use around a rod electrode passing along an axis through a hole in the wall of a furnace into the interior of the furnace has an annular and at least limitedly flexible seal ring fitted snugly around the electrode in the hole and a holder carrying the seal ring and sealingly engaged with the furnace wall. Thus gas flow through the wall at the hole past the seal ring is substantially blocked. The seal assembly has structure forming with the electrode and seal ring a substantially closed chamber surrounding the electrode axially inward into the furnace from the ring. This chamber is pressurized at superatmospheric pressure with an inert gas and the electrode is cooled inward of the furnace from the seal ring. The seal ring is compressed axially by a packing assembly so it is pressed radially against the electrode. The packing includes rigid split compression rings bearing axially on the seal ring.