| 摘要 |
PROBLEM TO BE SOLVED: To decrease a driving force of a source for driving of valve body. SOLUTION: A load-lock chamber 10 and a transportation chamber 12 are provided adjacent to each other to communicate with each other via a first opening 14 made in an interface therebetween. A valve body 18 abuts from inside the transportation chamber against an upper partition wall 12a having the first opening via an O ring 19 as a stationary sealing material. The valve body, which is coupled to a second actuator 26 by a shaft 24, can be moved in a vertical direction within the transportation chamber. A bellows 30 is provided within the transportation chamber as a movable sealing material to separate the transportation chamber from the second actuator. The bellows is provided around the shaft to seal up a space between the valve body and an inner wall of the transportation chamber, and to keep the side of the space having the shaft in an atmospheric pressure state. A diameter of the bellows is set to be larger than an outer diameter of the O ring when the valve body is seated. Since the diameter of the bellows is set to be equal to the diameter of a lower surface of the valve body, a positive pressure acting on the lower surface of the valve body is larger than a back pressure acting on the upper surface of the valve body. |
