Patent ID: 8397538

Claim:
An apparatus for forming a sheet of glass including a forming body ( 10 ) comprising a trough ( 12 ) and converging forming surfaces ( 16 a , 16 b ) that join at a root ( 18 ) such that molten glass ( 20 ) overflowing the trough forms multiple streams of molten glass that flow over the converging forming surfaces and combine at the root to form a glass ribbon ( 22 ), and wherein the forming body can be tilted relative to a horizontal plane, the apparatus further comprising: an upper transition member ( 34 ) that encloses the glass ribbon and is coupled to the forming body, the forming body defining a first interior space ( 36 ) through which the glass ribbon descends, and wherein the upper transition member can be tilted in unison with the forming body relative to the horizontal plane; a lower transition member ( 38 ) that encloses the glass ribbon and is positioned below the upper transition member, the lower transition member defining a second interior space ( 40 ) through which the glass ribbon descends; and wherein the upper transition member and the lower transition member are separated by a gap δ less than 8 cm and wherein the gap is positioned such that a viscosity of the glass ribbon adjacent to the gap is equal to or less than 10 7.3 poise.