Cooling system having a plurality of cooling stages in which refrigerant-filled chamber type refrigerators are used

A refrigerant-filled chamber type refrigerator comprising:

• a first cooling stage having a movable-type refrigerant-filled chamber;
• a second cooling stage having a static-type refrigerant-filled chamber;
• a gas compressor connected to the inlet side of the final cooling stage;
• a first valve disposed between the discharge side of the gas compressor and the inlet side of the final cooling stage;
• a second valve disposed between the suction side of the gas compressor and the inlet side of the final cooling stage;
• a first valve control unit for selectively opening/closing alternately the first and second valves to permit a high-pressure refrigerant gas discharge side of the gas compressor to be guided into the first cooling stage through the final cooling stage and then to permit said refrigerant gas to be sucked into the gas compressor through the suction side thereof via the reverse passageway so as to generate coldness;
• a third valve disposed between the other end portion of the first cooling stage and the discharge side of the gas compressor;
• a fourth valve disposed between the other end portion of the first cooling stage and the suction side of the gas compressor;
• and
• a second valve control unit for serving to open/close the third and fourth in relation to the opening/closing of the first and second valves.