Abstract: A process of manufacturing vitreous beads in which particulate feedstock is delivered to a heated chamber and passed along it so that the feedstock is heated and converted to vitreous beads whereafter the beads are collected, characterised in that the chamber is shaped to provide a flow path for the particles which is of elongate cross-section and is arranged so that the particles pass downwardly through it under gravity, and in that the particles passing through the chamber are heated by radiant heating means which emanates from the chamber walls.

Abstract: A spherulizing furnace for manufacturing vitreous beads includes feed means for delivering particulate feedstock, a spherulizing zone in which the feedstock particles may be heated and converted to vitreous beads, and means for collecting the resulting beads, wherein the feed means includes a reservoir adapted to hold a fluidized bed of feedstock particles, the reservoir having at least one overflow feed outlet opening over which fluidized particles flow under gravity for delivery to the spherulizing zone. A process of manufacturing vitreous beads, and vitreous beads made thereby, includes delivering feedstock to a spherulizing zone of a spherulizing furnace, passing the feedstock through the spherulizing zone so that the feedstock is heated and converted to vitreous beads, and collecting the beads. The feedstock particles are delivered under gravity by fluidized overflow from a fluidized bed reservoir to the spherulizing zone.

Abstract: A spherulizing furnace for manufacturing vitreous beads, including a chamber; means for heating the chamber; feed means for delivering a particulate feedstock to one end of the chamber; and means for collecting vitreous beads from another end of the chamber, wherein the chamber includes a pair of opposed walls which are spaced apart by a distance less than their breadth and which are angled to the horizontal so that the chamber has an upper end and a lower end, the feed means is arranged to deliver feedstock to the upper end of the chamber so that the feedstock can pass through the chamber under gravity, and the means for heating the chamber is arranged to heat at least one wall of the pair of opposed walls so that feedstock passing between the pair of opposed walls is heated by radiant heat.

Abstract: A method of forming rounded vitreous beads in which particles of bead forming material entrained in a gas stream having comburent and combustible components are projected from a burner head and the gas is burnt. A first component of the combustible gas mixture with entrained particles is propelled along a passageway leading to the burner head, a second gas component is forced transversely into that passageway through at least one orifice in its peripheral wall and the mixed gases in which the particles are entrained are subjected to forces further promoting intimate mixture thereof before reaching the burner head.