GB835203A - A new or improved method of and furnace for melting or refining glass - Google Patents

Abstract

835,203. Electric glass furnaces. ELEMELT Ltd. Aug. 20, 1956 [Aug. 20, 1955], No. 24052/55. Class 39(3) [Also in Group XXIII] In the melting or refining of glass by the passage through the melt of an electric current whilst the melt is contained in a furnace chamber, glass batch materials in the form of powdered or divided solids are fed on to the upper surface of the melt to form a heat conserving batch crust extending over substantially the whole of the upper surface leaving only a relatively narrow margin at the boundaries of the surface consisting of molten or partly molten glass with not more than a thin layer, if any, of the batch materials in solid form so that the crust floats freely on the surface and is not impeded in rising or falling by contact with the walls of the furnace chamber. The furnace chamber 10 has along each end wall 11 a series of electrodes 12 through which current is supplied to the whole width of the chamber. At a short distance above the normal surface level 13 of the melt, blocks are inserted in side and end walls 14, 11 to extend inwardly over the melt as sills 16, 15 with inclined under surfaces 17 so that they not only prevent radiation of the heat adjacent the walls but also reflect the radiated heat from the melt inwardly thereof. The batch crust 22 is sprinkled on the surface 13 by means of a carriage 18 having wheels 19 running on horizontal rails 20 supported on uprights 21 outside the end walls 11, the carriage being moved over the furnace to sprinkle the batch materials at a controlled rate across the whole width of the chamber between sills 16. The length of the opening in carriage 18 may be such that, normally, batch materials is not delivered on top of sills 15. A roof or crown to the furnace may be supported for lowering as required to close the chamber 10. Specifications 756,382, 823,769, 835,201 and 835,202 are referred to.