| 摘要 |
PURPOSE:To improve a cooling effect, and to enhance stability in molding by adiabatically expanding air supplied from an air feed pipe once in an expansion chamber, cooling air and blowing air off into a tubular resin. CONSTITUTION:Air for cooling at comparatively low pressure is supplied from a first air feed pipe 16, is supplied to the lower end side of a core 11 through a ventilating hole 22, and flows to the resin bubble 6C side. Consequently, a melted resin tubular body 6A not only is cooled from the outside by an air cylinder 8 but also is cooled from the inside. Air for cooling at comparatively high pressure is supplied from the second air feed pipe 17, ejected into the expansion chamber 23 in an adiabatic expansion manner once from outflow ports 24 and cooled, and adiabatically expanded secondarily from blow-off ports 25 and cooled again, and blown against a resin expanding section 6B. Accordingly, the resin expanding section 6B is cooled effectively. |
