Patent ID: 7127919

Claim:
A method for homogenizing molten glass comprising: (a) providing a cylindrically-shaped, substantially vertically-oriented stir chamber which comprises a wall having an internal diameter D wall ; (b) providing a stirrer within the stir chamber, said stirrer comprising a substantially vertically-oriented shaft and a plurality of blades which extend outward from the shaft towards the wall of the stir chamber, the maximum diameter of the blades being D blade ; (c) flowing molten glass through the stir chamber, said molten glass having a viscosity μ; and (d) applying a torque T to the shaft of the stirrer to rotate the stirrer within the stir chamber at a speed N as the molten glass flows through the chamber, said rotation of the stirrer within the chamber defining a swept volume V; wherein N, T, V, D wall , D blade , and μ are selected to satisfy the relationships: Relationship I: (NTV/μ) 0.5 ≧5.0 kilograms/second, and Relationship II: (2πμND blade )/(D wall −D blade ) ≦3.5×10 −3 newtons/meter 2 , where N is in radians per second, T is in newton-meters, V is in meters 3 , D wall is in meters, D blade is in meters, and μ is in kg/meter-second, and where Relationship I is a measure of stirring effectiveness and glass flow rate, and Relationship II is a measure of sheer stress acting on the stirrer and the stir chamber wall.