| 摘要 |
PURPOSE:To make transfer into and installation in a building easy by reducing the height of a cryostat by attaching a liquid helium port which is provided with a liquid helium pouring pipe shielded with a sealed structure insulating layer to a liquid helium inlet and the insulating layer for the inlet in a freely attaching or removing manner. CONSTITUTION:The joint 14 of a liquid helium port 10 is made to be free in attaching or removing and the connection of the flange 26 of a liquid helium pouring pipe and the flange 25 of the end of a port external cylinder 23a is made by tightening a clamp 16. Meanwhile, the shield plates 21b, 22b inside a port external cylinder 23b at the side of the liquid helium pouring pipe are fit on the ends of the shield plates 21a, 22a at the side of an inlet 20a by interposing guide members 21c, 22c and the end of an internal liquid helium pouring pipe 20b is fit on a guide member 20c at the end of the liquid helium inlet 20a closely. The airtightness of vacuum insulating layers 6a-6c at the side of the liquid helium inlet 20a is kept by the coupling of airtight members 24a-24c which close between the shield plates and even if the liquid helium pouring pipe 20b is removed from the joint 14, vacuum conditions and the sealing conditions of a liquid nitrogen tank are maintained. |
