JP2551067B

A refrigeration system includes a compression portion having a volume to be varied, a heat-accumulator fluidically connected to the compression portion, a condenser fluidically connected to the heat-accumulator and having an upper side and a lower side, an expansion portion having a volume to be varied at which a very low temperature is generated, a vessel containing an amount of liquid helium and having vapor phase of helium above the liquid helium, a first conduit for connecting the vapor phase of helium in the vessel and the upper side of the condenser, and a second conduit for connecting the liquid helium in the vessel and the lower side of the condenser. In such a system, since the compression portion is in fluid communication with the vessel via a first conduit and a second conduit, the substance immersed in the liquid helium in the vessel may be isolated from vibrations or magnetism from the compression portion by setting the length of each conduit at a suitable value. Further, since the introduction of vapor helium into the condenser is performed by convection and the liquid helium is returned to the vessel by gravity, the carrying or transfer of helium may be performed without a device such as a pump.