GB1017724A - Electric melting device, especially for high-melting materials, such as glass, rock, minerals and the like - Google Patents

Abstract

1,017,724. Electric resistance furnaces. A. WALZ. April 16, 1963, No. 14790/63, Heading H5H. A melting device, e.g. for use in the production of fibres from glass or minerals, includes two vertical coaxial resistance tubes into the annular space between which the charge to be melted is received, at least one of the tubes having its lower portion of reduced wall thickness, and the two tubes being connected together at their lower ends, adjacent which is an outlet for the melt. Glass 20 is melted, for the manufacture of fibres, in a resistance furnace having a resistive path between the current leads 19 and 4 constituted by an outer tube 1 joined at flange 6 to a further portion 7, 8, 9 of reduced wall thickness, ring 16, and an inner tube 12 having an upper portion 10 provided with coolant channels 11 The glass moves by gravity down the furnace, the intermediate tube 17 being axially adjustable to ensure that the glass contacts the inner tube only when sufficiently fluid to prevent sticking thereto; a further intermediate tube may similarly protect the outer tube 1, which may, alternatively, be vibrated. The molten glass flows through the radial bores 15 and out through aperture 14, the temperature being maintained constant by circuitry controlled by a thermocouple mounted within the inner tube 12. In a modification (Fig. 2, not shown), a plurality of exit apertures for the glass are provided in the annular portion of plate 16 between the inner and outer tubes. Tubes 1 and 10 are of stainless steel, or graphite, and portions 7, 8, 9 and 12 of a platinum alloy.