Patent ID: 7458235

Claim:
A method of making a glass fiber insulation product, comprising: (a) providing at least one glass material; (b) melting the glass material; (c) disposing said molten glass material in a spinner having a plurality of spinner orifices; (d) centrifuging the molten glass material through said plurality of spinner orifices to form a multiplicity of glass streams; (e) attenuating said glass streams with a gas current adjacent an exterior of the spinner to form glass fibers having an average diameter of no greater than about 3.5 microns, said gas current being substantially provided by a burner having a burner pressure of about 10-25 inches of water (250-635 mm CE), said burner having a pair of burner lip portions separated by a width of at least 8 mm; and (f) combining the fibers together with a resinous binder to form an insulation product having an ASTM C 686 parting strength of at least about 100 gf/g, and exhibiting a substantial recovery of its nominal thickness following compression; wherein the spinner of (c) and (d) has a peripheral band that is perforated with orifices distributed in a plurality of annular zones arranged on top of each other with the spinner in centrifugation position, and which includes at least two annular zones whose number of orifices per unit of surface area differs by at least a value of 5%, and wherein the annular zone containing a greatest number of orifices per unit of surface area is located below another annular zone, assuming that the spinner is in centrifugation position, wherein each annular zone of the spinner has orifices grouped in at least one row, with a distance between adjacent orifices in each row being substantially constant in each annular zone, and with the distance between adiacent orifices in each annular zone decreasing from one annular zone to another from a top to a bottom of the peripheral band.