Hybrid-two-stage pulse tube refrigerator

A two-stage pulse tube refrigerator for use in a cryogenic refrigeration system comprising:

• a refrigerant compressor having a high pressure discharge and a low pressure inlet;
• a first-stage regenerator having a warm end and a cold end;
• a second-stage regenerator having a warm end and a cold end, said warm end of such second-stage regenerator connecting to said cold end of said first-stage regenerator;
• a first-stage pulse tube having a warm end and a cold end, said cold end of said first-stage pulse tube being connected to said cold end of said first-stage regenerator;
• a second-stage pulse tube having a warm end and a cold end, said cold end of said second-stage pulse tube being connected to said cold end of said second-stage regenerator;
• two on/off valves connected to said warm end of said first stage regenerator and said compressor discharge and inlet;
• a plurality of buffers and an equal plurality of on/off valves respectively connecting said buffers to said warm end of said first stage pulse tube;
• one buffer of said plurality of buffers being connected to said warm end of said second stage pulse tube with a first fixed orifice;
• a second fixed orifice connecting between said warm end of said second stage pulse tube and said warm end of said first regenerator.

A two-stage pulse tube refrigerator for use in a cryogenic refrigeration system, comprising:

• a refrigerant compressor having a high pressure discharge and a low pressure inlet;
• a first-stage regenerator having a warm end and a cold end;
• a second-stage regenerator having a warm end and a cold end, said warm end of such second-stage regenerator connecting to said cold end of said first-stage regenerator;
• a first-stage pulse tube having a warm end and a cold end, said cold end of said first-stage pulse tube being connected to said cold end of said first-stage regenerator;
• a second-stage pulse tube having a warm end and a cold end, said cold end of said second-stage pulse tube being connected to said cold end of said second-stage regenerator;
• a first phase controller including a pair of on/off valves connected between said first-stage pulse tube warm end and said high pressure discharge and low pressure inlet respectively, and another pair of on/off valves connected between said warm end of said first stage regenerator and said compressor discharge and inlet;
• a second phase controller including two fixed orifices and a buffer, said buffer connecting to said warm end of said second stage pulse tube through one of said two fixed orifices, the other of said two orifices connecting said warm ends of said first stage regenerator and said second stage pulse tube;
• a third fixed orifice connecting said buffer to said first stage pulse tube warm end.

A two-stage pulse tube refrigerator for use in a cryogenic refrigeration system, comprising:

• a refrigerant compressor having a high pressure discharge and a low pressure inlet;
• a first-stage regenerator having a warm end and a cold end;
• a second-stage regenerator having a warm end and a cold end, said warm end of such second-stage regenerator connecting to said cold end of said first-stage regenerator;
• a first-stage pulse tube having a warm end and a cold end, said cold end of said first-stage pulse tube being connected to said cold end of said first-stage regenerator;
• a second-stage pulse tube having a warm end and a cold end, said cold end of said second-stage pulse tube being connected to said cold end of said second-stage regenerator;
• a first pair of on/off valves connected between said first-stage pulse tube warm end and said high pressure discharge and low pressure inlet respectively, and a second pair of on/off valves connected between said warm end of said first stage regenerator and said compressor discharge and inlet respectively, and a third pair of on/off valves connected between said warm end of said second stage pulse tube and said compressor discharge and inlet respectively;
• two fixed orifices and a buffer, said buffer connecting to said warm end of said second stage pulse tube through one of said two fixed orifices, the other of said two orifices connecting to said warm end of said first stage pulse tube.