Multistage type pulse tube refrigerator

A multistage type pulse tube refrigerator comprising:

• a regenerator-side pressure oscillation generator,
• a first regenerator connected to the regenerator-side pressure oscillation generator;
• a first cold head connected to a low temperature end of the first regenerator;
• a second regenerator connected to the first cold head;
• a second cold head connected to the second regenerator;
• a first pulse tube-side phase shifter;
• a first pulse tube having one end connected to the first cold head and another end connected to the first pulse tube-side phase shifter by way of a first flow regulating mechanism;
• a second pulse tube-side phase shifter;
• a second pulse tube having one and connected to the second cold head and another end connected to the second pulse tube-side phase shifter by way of a second flow regulating mechanism;
• and
• an operation timing for each of the first pulse tube-side phase shifter and the second pulse tube-side phase being controlled independently, and the phase angle with respect to the operation timing of the second pulse tube-side phase shifter relative to the regenerator-side pressure oscillation generator being from -15.degree. to -90.degree..

A multistage type pulse tube refrigerator comprising:

• a compressor having a discharge port and a sucking port for a working gas;
• a regenerator-side high pressure communication tube connected to the discharge port of the compressor;
• a high pressure opening/closing valve for regenerator disposed at a top end of the regenerator-side high pressure communication tube;
• a regenerator-side low pressure communication tube connected to the suction port of the compressor;
• a low pressure opening/closing valve for regenerator disposed at a top end of the regenerator-side low pressure communication tube;
• a first regenerator;
• a regenerator-side conduit for connecting the high pressure opening/closing valve for regenerator and the low pressure opening/closing valve for regenerator to the first regenerator;
• a regenerator-side valve control device for controlling opening/closing of the high pressure opening/closing valve for regenerator and the low pressure opening/closing valve for regenerator in an alternating manner;
• a first pulse tube-side high pressure communication tube connected to an intermediate point of the regenerator-side high pressure communication tube;
• a high pressure opening/closing valve for first pulse tube disposed at a top end of the first pulse tube-side high pressure communication tube;
• a first pulse tube-side low pressure communication tube connected to an intermediate point of the regenerator-side low pressure communication tube;
• a low pressure opening/closing valve for first pulse tube disposed to at a top end of the first pulse tube-side low pressure communication tube;
• a first pulse tube-side conduit for connecting the high pressure opening/closing valve for first pulse tube and the low pressure opening/closing valve for first pulse tube with a first pulse tube;
• a first pulse tube-side valve control device for controlling opening/closing of the high pressure opening/closing valve for first pulse tube and the low pressure opening/closing valve for first pulse tube in an alternating manner;
• a second pulse tube-side high pressure communication tube connected to an intermediate point of the regenerator-side high pressure communication tube;
• a high pressure opening/closing valve for second pulse tube disposed at a top end of the second pulse tube-side high pressure communication tube;
• a second pulse tube-side low pressure communication tube connected to an intermediate point of the first tube-side low pressure communication tube;
• a low pressure opening/closing valve for second pulse tube disposed at a top end of the second pulse tube-side low pressure communication tube;
• a second pulse tube-side conduit for connecting the high pressure opening/closing valve for second pulse tube and the low pressure opening/closing valve for second pulse tube with a second pulse tube;
• a second pulse tube-side valve control device for controlling opening/closing of the high pressure opening/closing valve for second pulse tube and the low pressure opening/closing valve for second pulse tube in an alternating manner;
• a first cold head having one end connected to the first refrigerator and an another end connected to the first pulse tube;
• a second regenerator having one end connected to the first cold head;
• a second cold head having one end connected to the second regenerator and another end connected to the second pulse tube;
• high/low pressure switching timing of the regenerator-side valve control device, the first pulse tube-side valve control device, and the second pulse tube-side valve control device being controlled independently;
• and
• the high/low pressure switching timing for the first pulse tube-side valve control device having a phase angle of from -50.degree. to -120.degree. relative to the high/low pressure switching timing for the regenerator-side valve control device, and the high/low pressure switching timing for the second pulse tube-side valve control device having a phase angle of from -15.degree. to -90.degree. relative to the high/low pressure switching timing of the regenerator-side valve control device.

A multistage type pulse tube refrigerator comprising:

• a compressor having a discharge port and a sucking port for a working gas;
• a switching valve having a high pressure input port in communication with the discharge port of the pressure oscillation generator, a low pressure input port in communication with the suction port of said pressure oscillation generator, a first output port, a second output port and a third output port;
• a first cold head;
• a first regenerator having one end in communication with the third output of said switching valve and another end in communication with the first cold head;
• a first pulse tube having one end in communication with the first cold head and another end in communication with said first output port of the switching valve by way of a flow regulating mechanism;
• a second cold head;
• a second regenerator having one end in communication with the first cold head and another end in communication with the second cold head;
• and
• a second pulse tube having one end in communication with said second cold head and another end in communication with said second output port of the switching valve by way of a second flow regulating mechanism;
• the switching valve being operationally positionable in a first position for communicating said first output port and said high pressure input port, a second position for communicating said second output port and said high pressure input port, a third position for communicating said third output port and said high pressure input port, a fourth position for communicating said first output port and said low pressure input port, a fifth position for communicating said second output port and said low pressure input port, and a sixth position for communicating said third output port and said low pressure input port;
• the phase angle between the first position and the third position being from -50.degree. to -120.degree., the phase angle between the second position and the third position being from -15.degree. to -90.degree., the phase angle between the fourth position and the sixth position being from -50.degree. to -120.degree., and the phase angle between the fifth position and the sixth position being from -50.degree. to -120.degree..