Rotary fiberizer

A method of forming fibers from molten mineral material is provided. The method comprising the steps of: rotating a spinner having an orificed peripheral wall, the orificed peripheral wall having a top row of orifices, introducing molten mineral material to the spinner to create a fan of primary glass fibers, creating an annular combustion flow of heated gas and directing the annular combustion flow of heated gas substantially through the primary fibers, creating an annular flow of attenuating air with an annular blower, the annular flow of attenuating air being sufficient to attenuate the primary fibers into secondary fibers, directing the annular combustion flow of heated gas and the annular flow of attenuating air so that they are radially spaced apart at the level of the top row of orifices, and directing the annular combustion flow of heated gas and the annular flow of attenuating air so that they are brought together at a position below the top row of orifices.