Method and apparatus for the simultaneous continuous production of a large number of threads by mechanical removal from heat plastic, mineral, in the form of be exported materials, in particular glass

摘要

A process for the continuous production of glass filaments comprises feeding a plurality of individual rods 1 (Fig. 1, not shown), guided near their lower end, into a linear tube-like enclosed heating zone 5 of more than 12 inches in length and heating the rods to form a fused glass mass having a series of lineal zones V1-V4 (Fig. 2, not shown) of equal viscosity, each zone merging with one immediately below it of lower viscosity, the zone of lowest viscosity V3 being divided into a large number of downwardly directed cylindrical streams in which the viscosity is increased to that necessary to form the drop for the continuous production of the filaments, which drops form automatically after a break in a filament and draw new filaments behind them. The tubular bushing 5 has a large number of depending cylindrical tubes 7 arranged in groups such that the distance between each group of tubes 7 and each individual tube 7 is greater than the diameter of a drop formed on the tip of each tube. As drops 10 fall drawing a filament 9 behind them they contact a curved plate 13 which guides them on to a first rotating drawing drum 12 which then causes the filaments to be drawn across the surface of a sizing roll 11, the angle between the vertical and the filament at the point of contact with roll 11 being very small. The bushing is made of platinum-rhodium alloy and is directly connected to an electrical supply so that it acts as its own heater. Only the bushing is insulated, the depending tubes being open to the movement of air so that they may be cooled. A suitable glass has the composition 68% SiO2, 4-6% Al2O3, 15% Na2O + K2O + B2O3 and the remainder alkaline earth oxides.