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. Apparatus for performing the method includes a burner head and conduit means for supplying the burner head which includes a first passageway for feeding a first component of a combustible gas mixture with entrained bead forming particles to the burner head, and a second passageway for force-feeding a second gas component transversely into such first passageway through one or more orifices in its wall to form a combustible admixture with said first gas component and the entrained particles. The burner tube is provided with an aperture for admitting the gas mixture to the burner tube transversely to the longitudinal axis of the burner tube.