| 摘要 |
PURPOSE:To obtain a capillary having a non-spherical hole by drawing a glass tube having uneven wall thickness at a temperature higher than the temperature causing its deformation under the collapsing force. CONSTITUTION:As starting material, a glass tube 1 having a spherical hole 1a and sectional shape provided, in an axially symmetrical way, with parts 12 of smaller wall thickness is used with one or both of the ends opened. The temperature of a hot oven is set at a level higher than the softening point of the glass tube 1's material and also higher than the temperature causing its deformation under the collapsing force. In this hot oven, the glass tube 1 is drawn at a specified rate while feeding an appropriate flow of a gas like N2 through a relevant feed pipe into the hole. The ratio of the inner diameter to outer diameter for the resulting capillary is regulated through heating temperature and/or drawing rate, thus giving the objective capillary 7 having a hole of non-spherical shape. |
