| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method and apparatus for controlling the stress in, and the shape of, a glass ribbon formed in a downdraw glass manufacturing process. <P>SOLUTION: The control is achieved by cooling the bead portions of the ribbon 15 at a rate which provides a heat flux Q"<SB>b</SB>at the thickest part of the bead which is given by the formula Q#3"<SB>b</SB>=Q"<SB>q</SB>+ΔQ", where (i) Q"<SB>q</SB>is the heat flux at a transverse position adjacent to the bead portion at which the ribbon's 15 thickness equals 1.05*t<SB>center</SB>, where t<SB>center</SB>is the final thickness at the ribbon's 15 center line, and (ii)ΔQ"≥(t<SB>b</SB>/t<SB>q</SB>-1)Q"<SB>q</SB>+10 kw/m<SP>2</SP>, where t<SB>b</SB>is the thickness of the thickest part of the bead portion. The cooling can take place along the entire length of the ribbon 15 or at selected locations, in the portion 50 of the draw which includes the glass transition temperature region 31 or the portion 60 of the draw where individual glass sheets 13 are cut from the ribbon 15. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
