GB258694A - Improved method of and apparatus for the manufacture of sheet glass - Google Patents

Abstract

258,694. Marks, E. C. R., (Danner, E.). July 6, 1925. Drawing. - A method of making sheet glass continuously consists in causing molten glass to flow in two or more separate streams from the same or different tanks, down two sides of an inclined or vertical guiding-member, or two or more guiding-members, the layers of glass flowing down the member uniting at the bottom to form a single sheet which is drawn off by suitable drawing-mechanism. By using different tanks, glasses of different colour can be united to form a single sheet. Reinforced sheet may be produced by introducing wire fabric between the layers before they unite to form the sheet. In the construction shown in Fig. 2, a forehearth 31, projecting from a tank furnace 30, is divided into three longitudinal compartments by partition blocks 46, Fig. 3, and the flow of glass into these compartments is controlled by adjustable gates 51. At the end of the central compartment, a well or flow-compartment 65 is provided and a slot or flow-opening is formed in its floor. Adjustable gates 71, 76 control the flow of glass into the well. The glass issuing from the slot flows on to, and down the sides and ends of, a flat or wedge-shaped slab or guiding-member 82 which is supported below the slot in a chamber formed by tiles 122. The chamber may be heated or cooled, as found necessary, to regulate the temperature and condition of the glass as it flows over the slab. The streams of glass flowing down the sides of the slab combine at the bottom to form a single sheet, which is drawn away by suitable mechanism, as described in Specification 126,747 and 159,114. Either the slab itself, or blocks associated with it, extend upwards through the slot, so that glass from the central and from the side compartments of the forehearth flow down different sides of the slab. The temperature of the glass flowing along the compartments is controlled by burners 111, 112, so that the temperature of the two streams of glass can be controlled and two streams of different condition can be obtained. The lower edge of the slab may be curved downwards at its ends, or it may be provided with side fingers, in order to prevent the immediate drawing-in of the edges of the sheet as it flows from the slab. The sheet is engaged by edge rollers 243, Fig. 17, and then passes over a curved deflecting slide 244 by which its movement is changed from vertical to horizontal before passing into the leer. The slide is watercooled and has its upper surface treated with graphite to prevent it from scratching the glass. In another form, the slide may consist of a roller path. Instead of using a single flowing-slot, two or three slots may be used, each with its associated slab. These slabs are inclined to one another in such a way that all the streams of glass flowing over their surfaces combine to form a single sheet. Wire mesh may be fed into the space between two slabs to form a reinforced sheet. Fig. 8 shows a construction in which glass from three sources of supply is combined to form a single sheet. Glass flows from a forehearth 320 down the sides of a slab 323, and other streams of glass from one or two pots 324 flow on to the sides of the slab near its lower edge, thus joining on to the layers of glass on the sides of the slab. In this way, a sheet may be made of two layers of glass of different colour. Specification 245,362 is referred to.