| 摘要 |
PURPOSE:To optionally select the sealing force and sticking force by relatively displaceably constituting the seal section of a vacuum container against the vacuum container via a spring, etc. in response to the pressure difference between the inside and outside of the vacuum container. CONSTITUTION:A cylindrical piston 6 is provided in a cylindrical vacuum container 1 capable of traveling via driving wheels 5, and this piston 6 is pressed by a spring 8 to the wall surface 12 side. A packing 7 preventing the atmospheric air from infiltrating through the sliding surface between the piston 6 and container 1 is provided in the piston 6. By making the spring constant of the spring 8 small, the piston 6 is moved up and down in response to the up-and-down displacement of the vacuum container 1, and the sealing force can be kept nearly constant. |
