| 摘要 |
PURPOSE:To take out liquid helium instantaneously as required by adjusting the flow of helium gas in a liquid helium vessel by using a check valve and a solenoid valve (a valve closing at the time of conduction) in parallel and keeping helium gas at a fixed pressure higher than atmospheric pressure. CONSTITUTION:Liquid helium collects in a cryostat 13 up to a fixed quantity, a solenoid valve 3 for pressure is closed at the same time as a level sensor senses liquid helium, and a solenoid valve 4 for recovery is opened while a solenoid valve 16 for follow-up pressure is closed. This state shows the flow of helium gas from a liquid helium vessel 22 as by the arrow 20 in the figure. Since a check valve 17 is formed in constitution in which it is closed at pressure lower than a certain constant pressure and opened at pressure higher than the certain constant pressure at that time, the internal pressure of the liquid helium vessel 22 is kept at fixed pressure. When a valve 21 for a liquid helium transfer pipe is opened when liquid helium is required in the cryostat 13, liquid helium is fed instantaneously into the cryostat 13 because the internal pressure of the liquid helium vessel 22 is kept elevated. |
