Method of producing fibers by internal centrifugation and the application of the said method to the drawing out of certain glasses into fibers

A method of obtaining mineral fibers by internal centrifugation, comprising the steps of:

• pouring a material to be drawn out into fibers, the material having a narrow range between the upper devitrification temperature and the drop resolution temperature, in a molten state, into the interior of a rotating centrifuge having a peripheral band pierced with a plural number of outlet orifices, such that the material may be drawn through the orifices to form fibers;
• maintaining an interior wall at an elevated temperature above the upper range of the devitrification temperature of the material such that the material in the centrifuge is above the upper range of the devitrification temperature and maintaining and outer wall of the peripheral band at a temperature lower than that of the interior wall and selected such that the fibers emerging from the orifices are below a drop resolution temperature of the material, whereby there exists a temperature gradient between the interior and outer walls;
• and
• permitting the material to be drawn through the orifices to form the fibers.