Method and apparatus for production of glass fibers utilizing spinning cup structure

Apparatus for producing glass fibers, comprising:

• an upwardly opening cup structure having a bottom wall and an upstanding peripheral side wall,
• means for rapidly spinning said cup structure about its central vertical axis,
• a plurality of fiber-extrusion holes in said upstanding side wall, some of said holes being located near said bottom wall, and some of said holes being remote from the bottom wall in an upper portion of the upstanding side wall,
• means for depositing a molten stream of glass onto the bottom wall of the cup structure, whereby centrifugal force produces a molten ring of glass on the upstanding side wall,
• furnace means above said cup structure and having an annular hot gas discharge slot for directing an annular stream of hot gas downwardly along the outer surface of the upstanding side wall, whereby glass fibers generated by flow through said holes are turned for movement downwardly through an annular space surrounding the spinning cup structure,
• an annular induction heater for heating the holes located near the cup structure bottom wall without heating the holes in the upper portion of the side wall, whereby all of the holes are maintained at about the same operating temperature,
• said heater being disposed in a plane generally coincident with the plane of the cup structure bottom wall, said heater having an inner surface spaced outwardly from the cup structure to define an annular space to accommodate downward movement of the glass fibers, and
• means for directing an annular curtain of relatively cool gas downwardly along the outer boundary of the annular hot gas stream, whereby the hot gas stream is guided to prevent its divergence from the cup structure side wall.