Quenching
Some manufacturers also will apply sulfur dioxide gas during the draw in order to change the chemistry of the glass on the surface. By changing the chemistry it is possible to affect the surface characteristics of the glass, improving its quality and durability.
Glass rollers hold the ribbon throughout various parts of the process, supporting its weight and continuing the drawing process.
The process continues as the ribbon is drawn upwards into a chimney like structure, where it is quenched or rapidly cooled. When the ribbon reaches the end of the process it is scored, or cut, and then removed for further processing in discrete sheets of flat glass.
The "bulb edges" are recycled as cullet (flawed glass which is remelted) or were resold for shelving or displays. Sometimes flawed parts of the sheets were removed, leaving behind decent quality flat glass.
Read more about this topic: Fourcault Process