Method and apparatus for forming glass beads

摘要

Beads of glass or other nitreous material are made by contacting a stream of the molten material with a diverging high velocity jet of gas or other fluid, which moves in a direction substantially parallel to the stream of molten material, and in sufficient proximity therewith to contact the stream and disperse it into a multiplicity of discrete particles which are shaped by surface tension into spherical form as they continue their movement along the path of the stream during cooling. A second fluid jet may be applied upstream of the high velocity fluid jet, and a third jet may be applied downstream of it. The fluid may be e.g. air at room temperature or steam. In one embodiment (Fig. 1), molten glass is discharged from furnace 15 through aperture 21 in drain-out block 20, which is heated by burner 25. The stream of molten glass is contacted by gas jets issuing from nozzles 30, 31 and 32 which are connected via pipes and conduits to manifold 42 in communication with pressure source 43. Flow of gas is controlled by valves 39, 49 and 56. Each nozzle is of flattened, rectangular cross-section (Fig. 2), the area of discharge opening of nozzle 31 being less than that of nozzles 30 and 32. The glass stream is directed horizontally by the jet from 30 and directed slightly upwards and dispersed into particles by the higher velocity jet from 31. The particles are given extra lift and thus a longer arcuate path before falling by the upwardly directed jet from 32. The diameter of the beads is varied by adjusting the velocity of the gas jet from nozzle 31. The positions of the jets relative to the glass stream are varied by means of pivots 36, 46 and 53 on nozzles 30, 31 and 32 respectively. The discharge opening of the drain-out block may be of rectangular cross-section, so that the stream of glass is flattened.