| 摘要 |
An apparatus for cooling a cooled piece of equipment, such as a superconducting magnet, comprises a cryogen vessel 10 housing the cooled equipment, a gaseous cryogen filling the cryogen vessel, and a refrigerator 12 having a cooling surface exposed to the interior of the cryogen vessel so as to cool the gaseous cryogen. The refrigerator is positioned asymmetrically on the cryogen vessel so as to cause free circulation of the gaseous cryogen by thermal convection within the cryogen vessel. Alternatively, a gas current generator 14 is arranged to cause free circulation of the gaseous cryogen within the cryogen vessel. The gaseous cryogen is cooled by the refrigerator and is warmed by heat from the cooled equipment thereby cooling the cooled equipment. The gas current generator may be a fan or a heater. Preferably, the gaseous cryogen comprises at least one of helium, nitrogen, argon, hydrogen and neon. The apparatus may be provided with a quantity of liquefied gaseous cryogen, out of contact with the cooled equipment but in thermal equilibrium with the gaseous cryogen within the cryogen vessel, sufficient to ensure that an adequate supply of gaseous cryogen gas is present. |
