| 摘要 |
PURPOSE:To decrease the strain of a bulb which is caused after the bulb is formed into a circular shape, and prevent the generation of any crack by adjusting both the temperature and the pressure of cooling hot air to values within the appropriate given ranges. CONSTITUTION:A bulb 2 made of a heated and softened low-lead glass or soda lime glass is attached to a supporting tool 3 and is left to hang down, and the lower end of the bulb 2 is attached to a drum 1. while nitrogen is supplied from a supply pipe 5, the bulb 2 is coiled around the drum 1 into a circular shape by moving the drum 1 upward. Following that, a circular bulb 4 is cooled with air sprayed from a nozzle 6. The temperature of the cooling hot air is adjusted to in the range of 60-120 deg.C, while the pressure of that is adjusted to in the range of 0.8-1.5kg/cm<2>. |
