| 摘要 |
PURPOSE:To prevent ununiform flow of cooling air and to obtain films in a high speed, moreover which few of ununiform thickness section and folding width fluctuation, by a method wherein a ring type perforated tube is provided inside of a slit of a ring type cooling medium room. CONSTITUTION:A molten tube 3 which is pushed out from a ring type dice 1, is pre-cooled by a cooling medium which came passing through the ring type perforated tube 4 at the space which is composed by the ring type perforated tube 4 and the molten tube 3, and passes through a rectifying tube 6 of hollow column type which is provided to prevent the effect of ununiform flow of the cooling medium in an air chamber, and subsequently said molten tube is expanded being fully cooled by the rising cooling medium which blows through a gap 10 which is composed with a controlling ring 5 provided at the upper part of the screen tube 7 and the molten tube 3, and forms a frost line. |
