Pulse tube refrigerator

A pulse tube refrigerator comprising:

• a pulse tube having a low-temperature end and a high-temperature end;
• a cold accumulator having a low-temperature end and a high-temperature end;
• an endothermic connection passage interconnecting the low-temperature end of said cold accumulator to the low-temperature end of said pulse tube;
• a compressor having a high-pressure port and a low-pressure port;
• a low-pressure refrigerant gas return passage connected to the low-pressure port of said compressor;
• a refrigerant gas passage connecting the high-pressure port of said compressor to the high-temperature end of said cold accumulator, said refrigerant gas passage being adapted to be supplied with a refrigerant gas from the compressor to be delivered to the high-temperature end of said pulse tube through said cold accumulator and said endothermic connection passage;
• first and second three-way valves arranged in parallel in said refrigerant gas passage, each of said first and second three-way vanes having an associated low-pressure port;
• a main gas passage fluidly communicating said first three-way vane with the high temperature end of said cold accumulator;
• a sub gas passage fluidly communicating said second three-way vane with the high-temperature end of said pulse tube;
• means for interconnecting the low-pressure port of each of said first and second three-way valves to the low-pressure refrigerant gas return passage;
• a flow regulating member interposed in the sub gas passage;
• means for synchronously shifting said first and second three-way valves;
• and
• means for adjustably changing opening/closing timings of one of said first and second three-way valves relative to the other of said first and second three-way valves.