| 摘要 |
PURPOSE:To strengthen a jet power and to prevent the adhesion of a melted matter on a lens by opening an assisting gas inlet port in the contact line direction close to the upper end, by providing a spiral line on the inner wall and by forming a gas spiral line stream in the conical nozzle connecting to a cylindrical part and condensing lens. CONSTITUTION:An assisting gas is passed in from the assist gas inlet port 4 opened in the contact line direction close to the upper end of a nozzle 3 and becomes a rotating stream in the nozzle 3. The assist gas becomes a spiral stream toward the lower part because of the upper part being partitioned by a lens 2 and a spiral line being provided on the inner wall of the nozzle. Due to the inner diameter of the conical nozzle 3 being reduced toward the outlet port the angular velocity of the rotation of the gas is gradually increased and the linear velocity is gradually increased as well. The gas jet velocity is therefore increased because of the rotation velocity having a bigger angular velocity being added to the increased linear velocity at the jet port. This is achieved almost without increasing the inner gas pressure nor gas flow quantity and the vapor of the melted matter invading from the nozzle 3 is completely stopped. |
