Patent ID: 9038415
Filing Date: 2015-05-26
Classification: C03B

Abstract:
1. An apparatus for making a glass sheet using a fusion down-draw process, comprising a forming body having an upper part ( 101 ) made of a first material and a lower part ( 103 ) made of a second material below said upper part ( 101 ), wherein the upper part ( 101 ) comprises two upper trough walls ( 112 , 114 ) and a trough bottom defining a trough space ( 105 ) for accepting molten glass, and the lower part ( 103 ) has a wedge-shaped cross-section having two major surfaces sloping downwardly to join at a root, and the side walls of the upper part ( 101 ) and the lower part ( 103 ) form substantially two continuous forming surfaces on which streams of molten glass can flow downwardly to join at the root ( 108 ) during normal operation, the first material has a creep rate at 1200° C. of CR1, and the second material has a creep rate at 1200° C. of CR2, and CR1<CR2, wherein the first material consists essentially of α-SiC, silicon nitride or silicon oxynitride, and the second material consists essentially of zircon.