The building a bridge device null in the production process of the optical

摘要

PURPOSE:To carry out quick cooling and quick heating according to ascending and descending velocity of fiber drawing velocity and to efficiently carry out bridge formation by providing infrared ray irradiation means around a cooling gas flow passage disposed in the passage of fiber drawing. CONSTITUTION:A cooling gas passing tube 12 of double pipe structure is disposed around the glass pipe 11 through which the naked optical fiber 4 applied with a thermosetting resin is passed. Infrared ray heaters 13, 13... are disposed 1n the four direction around the cooling gas passing tube 12 to project infrared rays to the naked optical fiber 4. In fiberpassing, the flow rate of cooling gas flowing through the cooling gas passing tube 12 is increased so that the amount of infrared rays reached the coating material applied to the naked optical fiber 4 is decreased, and a quick cooling is carried out around the naked optical fiber 4 drawn into fiber and passing through the glass pipe 11. When the bridle formation is to be made, the flow rate of cooling gas is decreased to increase the infrared rays to quickly raise the temp. around the naked optical fiber 4 so that the bridge formation is efficiently carried out.