| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent vaporization of a liquefied gas to the utmost in the case of a long transport distance by forming a first pipe capable of circulating an extremely low temperature liquefied gas, a second pipe capable of circulating a cooling gas to a circumference of the first pipe, and a vacuum layer for a heat insulation around the second pipe. SOLUTION: A helium gas whose temperature is raised is sucked by a dry pump through a helium gas recovery pipe, and is supplied to a first heat exchanger. It is cooled to about 40 deg.K, and the cooled helium gas is supplied into a liquefied helium reserving layer through a flow passage in a transfer line. The cooled helium gas supplied to the transfer line is supplied to a liquefied helium reserving tank through a pipe 24 while passing the space between a first pipe 21 and a second pipe 22 in the transfer line 9, and while the first pipe 21 is not brought into contact with a high temperature part. A circumference of the second pipe 22 is formed as a vacuum layer, the helium gas is completely shut out from an outside air so as to improve heat insulating effect. It is thus possible to prevent vaporization of the liquefied gas to the utmost.</p> |
