A cryogenic apparatus (10) includes an enclosure (12), a first thermo-mechanical cooler (20) and a second thermo-mechanical cooler (22) which project into the enclosure (12), at least the second thermo-mechanical cooler (22) being a two-stage cooler, and each cooler (20, 22) having a fluid inlet and a fluid outlet for each stage, and a helium gas extraction flow duct (40) which extends into the enclosure (12) and which communicates with a vessel (42) to contain liquid helium within the enclosure (12). There is a first heat exchanger (62) within the gas flow duct (40). A first duct (74) carries cold helium gas from a fluid outlet (73) of the first thermo-mechanical cooler (20) and through the first heat exchanger (62) to the fluid inlet (75) of the second stage of the second thermo-mechanical cooler (22).

A cryogenic apparatus (10) includes an enclosure (12), a first thermo-mechanical cooler (20) and a second thermo-mechanical cooler (22) which project into the enclosure (12), at least the second thermo-mechanical cooler (22) being a two-stage cooler, and each cooler (20, 22) having a fluid inlet and a fluid outlet for each stage, and a helium gas extraction flow duct (40) which extends into the enclosure (12) and which communicates with a vessel (42) to contain liquid helium within the enclosure (12). There is a first heat exchanger (62) within the gas flow duct (40). A first duct (74) carries cold helium gas from a fluid outlet (73) of the first thermo-mechanical cooler (20) and through the first heat exchanger (62) to the fluid inlet (75) of the second stage of the second thermo-mechanical cooler (22).

A cryocooler includes a cold head including a displacer movable in an axial direction, a drive piston connected to the displacer to move the displacer in the axial direction, an expansion chamber formed with the displacer, a piston drive chamber formed with the drive piston, a spool valve including a valve drive chamber, a spool that moves between a first position and a second position in response to a pressure of the valve drive chamber, and a pressure control mechanism configured to control a pressure of the valve drive chamber so that the spool reciprocates between the first position and the second position, and to generate a pressure fluctuation having an opposite phase to the pressure fluctuation in the expansion chamber in the piston drive chamber in synchronization with the reciprocation of the spool.

A cryocooler includes a cold head including a displacer movable in an axial direction, a drive piston connected to the displacer to move the displacer in the axial direction, an expansion chamber formed with the displacer, a piston drive chamber formed with the drive piston, a spool valve including a valve drive chamber, a spool that moves between a first position and a second position in response to a pressure of the valve drive chamber, and a pressure control mechanism configured to control a pressure of the valve drive chamber so that the spool reciprocates between the first position and the second position, and to generate a pressure fluctuation having an opposite phase to the pressure fluctuation in the expansion chamber in the piston drive chamber in synchronization with the reciprocation of the spool.

An improved cryogenic cooling system is disclosed. The cryogenic cooling system comprises a pressure sensing system disposed at or near the cryocooler to provide a more accurate representation of the pressure of the working gas within the cryocooler. By utilizing pressure measurements at the cryocooler, the thermal performance and net cooling capacity of the system may be improved. This may also improve the life of the cryocooler. Further, in some embodiments, pressure sensing systems are disposed at both the compressor and the cryocooler. In these embodiments, performance issues and potential failures may be monitored.

An improved cryogenic cooling system is disclosed. The cryogenic cooling system comprises a pressure sensing system disposed at or near the cryocooler to provide a more accurate representation of the pressure of the working gas within the cryocooler. By utilizing pressure measurements at the cryocooler, the thermal performance and net cooling capacity of the system may be improved. This may also improve the life of the cryocooler. Further, in some embodiments, pressure sensing systems are disposed at both the compressor and the cryocooler. In these embodiments, performance issues and potential failures may be monitored.

A cryogenic cooling system includes a gas circulation source; a cryocooler that cools a cooling gas; a cooling gas flow path that causes a cooling gas to flow from the gas circulation source to the object to be cooled; and a control device that controls the gas circulation source so as to execute initial cooling of the object to be cooled according to a prescribed flow rate pattern. The prescribed flow rate pattern is predetermined such that the cooling gas flows through the cooling gas flow path at a first average flow rate, and the cooling gas flows through the cooling gas flow path at a second average flow rate. The second average flow rate is smaller than the first average flow rate such that the cooling capacity of the cryogenic cooling system is increased.

A cryogenic cooling system includes a gas circulation source; a cryocooler that cools a cooling gas; a cooling gas flow path that causes a cooling gas to flow from the gas circulation source to the object to be cooled; and a control device that controls the gas circulation source so as to execute initial cooling of the object to be cooled according to a prescribed flow rate pattern. The prescribed flow rate pattern is predetermined such that the cooling gas flows through the cooling gas flow path at a first average flow rate, and the cooling gas flows through the cooling gas flow path at a second average flow rate. The second average flow rate is smaller than the first average flow rate such that the cooling capacity of the cryogenic cooling system is increased.

An acoustic wave generation unit oscillates working fluid of 35 atm or less so as to generate acoustic waves with a frequency in a range from 50 Hz or more and 500 Hz or less. A heat/acoustic wave conversion component has a partition wall of 5.0 W/mK or less between two end faces which defines a plurality of cells of 620 cells/cm.sup.2 or more and 3100 cells/cm.sup.2 or less. A heat exchanger disposed close to one end face receives heat from a first external air flowing into the heat exchanger and gives the heat to the one end face so as to flow out a cold air. Another heat exchanger disposed close to the other end face receives heat from the other end face and gives the heat to a second external air flowing into the another heat exchanger so as to flow out a warm air.

An ejector-based cryogenic refrigeration system for cold energy recovery includes a first cryogenic refrigeration loop connected by a helium compressor and a cryogenic refrigerator and a second cryogenic refrigeration loop connected by the helium compressor, a regenerator, an ejector, a cold head of the cryogenic refrigerator, an end to be cooled and a pressure regulating valve. The cryogenic refrigerator is separated from the end to be cooled. The cryogenic refrigerator and the cryogenic helium cooling loop share a helium compressor, which improves the utilization efficiency of the device and reduces the cost. The ejector allows a part of fluids to circulate in the cryogenic loop, so as to maintain a required cryogenic condition, recover the pressure of the fluids, reduce the gas flowing though the compressor loop, and thus reduce the power consumption of the compressor.