METHOD FOR MANUFACTURING GLASS TUBE AND GLASS TUBE

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass tube which can suitably manufacture a glass tube even if the glass tube has a large diameter or a large thickness.SOLUTION: A glass plate 11 is arranged on a molding die 10 with a cross section having a circular outer peripheral surface 12. A first deformation step is performed where the glass plate 11 is heated to be deformed by its self-weight and the glass plate 11 is deformed along an upper part of the outer peripheral surface 12 of the molding die 10. After the first deformation step, a second deformation step is performed where one side part of the glass plate 11 is pressed to the molding die 10 side by a first press member 21 located on one side of the molding die 10 and the other side part of the glass plate 11 is pressed to the molding die 10 side by a second press member 22 located on the other side of the molding die 10 to deform the glass plate 11 into an annular shape. After the second deformation step, a joining step is performed where two ends parts facing each other are joined to obtain a glass tube.