| 摘要 |
PURPOSE:To intercept the heat current from a fire to prevent it from being transmitted to a unit where an optical fiber core is coated and protected with metals, by providing this unit on a heat resisting tube consisting of ablating materials. CONSTITUTION:A heat resisting tube 1 consisting of ablating materials is provided. Ablating materials are a resin such as phenolic resin and polyamide resin reinforced by fibers such as glass fiber and carbon fiber, and these materials are formed to a shape like a pipe. Optical fiber units 3 armored by corrugate metallic tubes 2 and a tension member 4 are provided in the tube 1. The optical fiber unit 3 consists of an optical fiber core 5, a metallic coat 6 formed on the outside circumference of the core 5 by vapor-deposition method or the like, and a flexible metal tube 7 which protects the coat 6. |
