| 摘要 |
PURPOSE:To minimize invasion of heat to a chamber kept at an extremely low temperature, in an emergency gas discharging device for an insulated container for a material such as liquid helium at an extremely low temp, by providing its top and bottom sections with shut-off sections designed to be opened at a prescribed pressure and keeping inside of the container in vacuum. CONSTITUTION:A receptacle 14 of an emergency gas discharging device 17 is provided in such a manner as to pierce a vacuum space 4 on the top of an inner tank 2 of a container kept at an extremely low temp. and to project outwardly from an outer tank 5 kept at an extremely low temperature, and shut-off sections 12 and 13 are provided on the top and bottom of the receptacle. The shut-off sections are provided with a burst plate and a spring type safety valve, etc. As the receptacle 14 is kept in a vacuum condition at the normal temperature, there is no invasion of heat at all to the inside from outside at normal temperature by the heat transfer mode, such as, heat conduction, heat oscillation and heat convection, etc. And therefore, invasion of heat to the inner tank 2 of the container kept at the low temp. is reduced and evaporation of liquid helium 3 is decreased. |
