Patent ID: 7854132

Claim:
A circulation cooling system for a cryogenic cable comprising: a reserver unit for storing a refrigerant and a cable cooling portion for cooling down a cable by the refrigerant sent from said reserver unit, the system returning the refrigerant sent from said cable cooling portion to said reserver unit again for circulation; and a pressure feed pump located within the reserver unit configured to circulate the refrigerant in liquid form; wherein the system has a refrigerant temperature adjustment mechanism to keep constant an amount of the refrigerant within said reserver unit and the refrigerant temperature adjustment mechanism is configured to adjust the temperature of the refrigerant to maintain the refrigerant in liquid form; and wherein the refrigerant temperature adjustment mechanism includes a heat exchange unit that has a copper block in heat flow communication with a cold head of a refrigerating machine with a transport pipe holding the refrigerant wound around the copper block; wherein the system includes a fluid flow path that is in fluid flow communication with the cable cooling portion, the refrigerant temperature adjustment mechanism, and the pressure feed pump; wherein the fluid flow path is configured to be a closed flow path for the refrigerant; and wherein the reserver unit includes a closed container that is configured to allow the refrigerant to flow from the reserver unit through the fluid flow path.