| 摘要 |
PURPOSE:To prevent a movable seal from being frozen and deformed by forming a room which is filled with warm gas at the low-temperature side of the movable seal so as to keep the movable seal in the atmosphere of a room air temperature. CONSTITUTION:A general-type movable seal 1 is formed on a projecting part 2 functioning as a wall which cuts off communication between a room 10 having normal atmosphere and a space 7 having the atmosphere of low temperature. A room 3 which is cut off to be communicated with a low-temperature atmosphere space 7 which is to be filled with warm gas by use of a cut off wall 5 is formed at the low-temperature side of the projecting part 2. The room 3 has both a port 9 from which warm gas is to be supplied and another port 6 from which warm gas is to be supplied and another port 6 through which the movable part 8 is to travel. The low-temperature atmosphere space 7 has an exhaust port 4. The exhaust port 4. The exhaust port 4 is a port which serves to discharge frozen steam produced when the low-temperature atmosphere space 7 is reduced in temperature and also serves to supply anti-freezing medium. The port 4 will be formed as an occasion demands. |
