METHOD AND APPARATUS FOR FORMING GLASS TUBING FROM GLASS PREFORMS

Methods of forming a glass tube are described. In one embodiment, the method includes heating a glass boule to a temperature above a glass transition temperature of the glass boule, drawing the glasstube from the glass boule in a vertically downward direction, and flowing a pressurized gas through a channel of the glass boule as the glass tube is drawn. The glass boule includes an outer surface defining an outer diameter of the glass boule and a channel extending through the glass boule defining an inner diameter of the glass boule. Drawing the glass tube decreases the outer diameter of the glass boule to an outer diameter of the glass tube and flowing the pressurized gas through the channel increases the inner diameter of the glass boule to an inner diameter of the glass tube. Glass boules, glass tubes, and apparatuses for making the same are also described. 描述了形成玻璃管的方法。在个实施方式中，方法包括：将玻璃坯块加热到高于玻璃坯块的玻璃转化温度的温度，以垂直向下方向从玻璃坯块拉制玻璃管，以及当拉制玻璃管时，使加压气体流动通过玻璃坯块的通道。玻璃坯块包括限定了玻璃坯块的外直径的外表面和限定了玻璃坯块的内直径的延伸通过玻璃坯块的通道。对玻璃管进行拉制使得玻