METHOD AND APPARATUSE FOR CONTROLLING GLASS TUBE TAPER

A glass tube manufacturing apparatus for manufacturing glass tubing includes a glass delivery tank with molten glass. The glass delivery tank has a bottom opening. A bell has an upper portion with anouter diameter located at the bottom opening. A heating apparatus is at least partially disposed around the bell. The heating apparatus includes a heating portion and a muffle portion located below the heating portion. A lower extended muffle structure extends downwardly from the muffle portion. The lower extended muffle structure extends about a periphery of the glass tubing to manage convectiveairflow therethrough. 用于制造玻璃管的玻璃管制造设备包括具有熔融玻璃的玻璃输送槽。玻璃输送槽具有底部开口。钟形件具有上部部分，其具有外直径，所述外直径在所述底开口处。加热设备至少部分设置在钟形件周围。所述加热设备包括加热部分和位于加热部分下方的围裹部分。延伸的下围裹结构从围裹部分向下延伸。延伸的下围裹结构围绕玻璃管的外周延伸以管理从中通过的对流空气流。