Abstract: A cryocooler includes an expansion chamber, a cooling stage thermally coupled to the expansion chamber, the cooling stage including a first heat transfer block provided with a surface exposed to the expansion chamber and a first heat exchange surface disposed outside the expansion chamber and a second heat transfer block provided with a second heat exchange surface facing the first heat exchange surface, a refrigerant supply port installed in the cooling stage outside the expansion chamber, a refrigerant discharge port installed in the cooling stage outside the expansion chamber, and a refrigerant path fluidically separated from the expansion chamber, the refrigerant path being formed between the first heat transfer block and the second heat transfer block such that a refrigerant flows from the refrigerant supply port to the refrigerant discharge port along the first heat exchange surface and the second heat exchange surface.

Abstract: A first-stage regenerator material and a second-stage regenerator material are regenerator materials each having a laminated structure for use in a GM refrigerator. Each layer of the regenerator material is provided with a plurality of holes to allow gas to pass therethrough along a laminating direction. At least one layer includes a base material and a coating covering the base material. Volumetric specific heat of the coating is larger than volumetric specific heat of the base material in a temperature range from 20 K to 40 K.

Abstract: Losses in the connecting line between the Pressure Wave Generator and the cold head of a GM type pulse tube refrigerator, are reduced while maintaining or improving upon the desirable features of a standard corrugated hose connecting line including vibration isolation, separation distance, and mounting convenience. The basic means are to reduce the internal void volume of the convolutions in a corrugated hose in combination with reducing the number of corrugations, adding fillers to the void volumes, and vibration absorbing coatings.

Abstract: A pulse tube cryocooler which includes a pulse tube having a pulse tube high-temperature end and a pulse tube low-temperature end, and extending in an axial direction from the pulse tube high-temperature end to the pulse tube low-temperature end. The pulse tube cryocooler further includes a regenerator having a regenerator high-temperature end and a regenerator low-temperature end, and being disposed rowed alongside the pulse tube, with the regenerator high-temperature end being positioned displaced, in terms of the axial direction, from the pulse tube high-temperature end toward the cryocooler low-temperature side, and the regenerator low-temperature end being fluid-passage linked with the pulse tube low-temperature end and a pressure-switching valve for connecting the regenerator high-temperature end to a high-pressure source and to a low-pressure source in alternation, and being disposed between the pulse tube high-temperature end and the regenerator high-temperature end in terms of the axial direction.

Abstract: A pulse tube refrigerating machine enables maintenance of an orifice while circulation of refrigerant gas within individual components is allowed, thus reducing the time required for maintenance. A compressor delivers a refrigerant gas having a high pressure and sucks the refrigerant gas having a low pressure. A cold head including a regenerator tube through which the refrigerant gas circulates and a pulse tube is connected to a housing. The flow of the refrigerant gas is controlled by one or more orifices, which are disposed outside the housing. The compressor, the housing, and the orifices are coupled via tubing. A coupling unit is disposed at both ends of at least one of the orifices. The coupling unit has a structure such that it can be split while the refrigerant gas is retained within the tubing. When the coupling unit is split, a detachable unit portion including the orifice is isolated.

Abstract: In a cryocooler for developing coldness of 4 K or lower by expanding helium, an expander expands high-pressure helium. A compressor compresses low-pressure helium returned from the expander, to generate high-pressure helium, and supplies the high-pressure helium to the expander. When helium temperature in the expander is 2.17 K or lower, the pressure of the low-pressure helium is equal to or higher than pressure given by a curve, in a helium state diagram in which the horizontal axis is temperature and the vertical axis is pressure, along which helium's volumetric thermal expansion coefficient is 0.

Abstract: A pulse tube cryocooler includes a pulse tube that includes a tube inner space, and an integral flow straightener that includes a flow straightening layer disposed to face the tube inner space so as to straighten a refrigerant gas flow from the tube inner space or into the tube inner space and a heat exchange layer formed integrally with the flow straightening layer outside the flow straightening layer with respect to the tube inner space so as to exchange heat with the refrigerant gas flow by contact with the refrigerant gas flow and is disposed at a low-temperature end and/or a high-temperature end of the pulse tube. The flow straightening layer includes a plurality of protrusions that protrude from the heat exchange layer toward the tube inner space.

Abstract: There is provided a cryocooler including a cylinder, a displacer disposed inside the cylinder and driven to reciprocate by a gas pressure, a collar rigidly connected to the displacer to reciprocate together with the displacer, a collar chamber divided into an upper section and a lower section by the collar, a second seal portion provided between the displacer and the cylinder to seal the lower section, a lower bumper provided in the lower section to mitigate interference between the displacer and the cylinder when the displacer is located at a bottom dead center, and a communication passage formed in the collar or in the collar chamber to ensure communication between the upper section and the lower section when the displacer is located at a bottom dead center.

Abstract: A rotary valve unit includes a rotary valve and a reversible motor. The rotary valve operates according to a cooling valve timing for cooling a pulse tube cryocooler when the reversible motor rotates in a forward direction and is operated according to a heating valve timing for heating the pulse tube cryocooler when the reversible motor rotates in a backward direction. The cooling valve timing is designed to generate a working gas pressure oscillation in a pulse tube and apply a first phase delay to a working gas displacement oscillation in the pulse tube with respect to the working gas pressure oscillation. The heating valve timing is designed to generate the working gas pressure oscillation in the pulse tube and apply a second different phase delay to the working gas displacement oscillation in the pulse tube with respect to the working gas pressure oscillation.

Abstract: A pulse tube cryocooler is furnished with a second-stage cooling stage and an insert. The second-stage cooling stage has a lateral-surface opening, and a first heat-exchange surface extending in a sideways direction from the lateral-surface opening into the second-stage cooling stage. The insert includes a base-end portion fixedly fitted into the second-stage cooling stage to plug the lateral-surface opening, and a second heat-exchange surface that extends in the sideways direction from the base-end portion and is disposed inside the second-stage cooling stage, opposing the first heat-exchange surface. Between the first heat-exchange surface and the second heat-exchange surface the insert forms a clearance that flows a working gas, bringing both the first heat-exchange surface and the second heat-exchange surface into contact with the working gas.

Abstract: 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.

Abstract: A rotary valve of a cryocooler includes a valve stator, a valve rotor, a rotation member that rotates the valve rotor around an axis with respect to the valve stator, and a rotor holder connected to the valve rotor so as to rotate around an axis together with the valve rotor, and forming a low pressure section having a pressure lower than an ambient pressure between the valve rotor and the rotor holder so as to reduce an axial force of pressing the valve rotor against the valve stator. The rotation member is connected to the rotor holder so as to rotate the valve rotor around the axis via the rotor holder. The rotor holder is disposed between the rotation member and the valve rotor in an axial direction, and is movable in the axial direction with respect to the rotation member.

Abstract: A cryocooler includes an attachment flange including a refrigerant gas introduction port through which refrigerant gas is introduced into a recondensing chamber from an ambient temperature environment, and attachable to the recondensing chamber, and a cooling stage that is disposed inside the recondensing chamber when the attachment flange is attached to the recondensing chamber. The refrigerant gas introduction port is perpendicularly or obliquely oriented with respect to an axial direction of the cryocooler so that a refrigerant gas flow exiting the refrigerant gas introduction port deviates from the cooling stage.

Abstract: A cryocooler includes an expansion chamber, a cooling stage thermally coupled to the expansion chamber, the cooling stage including a first heat transfer block provided with a surface exposed to the expansion chamber and a first heat exchange surface disposed outside the expansion chamber and a second heat transfer block provided with a second heat exchange surface facing the first heat exchange surface, a refrigerant supply port installed in the cooling stage outside the expansion chamber, a refrigerant discharge port installed in the cooling stage outside the expansion chamber, and a refrigerant path fluidically separated from the expansion chamber, the refrigerant path being formed between the first heat transfer block and the second heat transfer block such that a refrigerant flows from the refrigerant supply port to the refrigerant discharge port along the first heat exchange surface and the second heat exchange surface.

Abstract: A rotary valve unit includes a rotary valve and a reversible motor. The rotary valve operates according to a cooling valve timing for cooling a pulse tube cryocooler when the reversible motor rotates in a forward direction and is operated according to a heating valve timing for heating the pulse tube cryocooler when the reversible motor rotates in a backward direction. The cooling valve timing is designed to generate a working gas pressure oscillation in a pulse tube and apply a first phase delay to a working gas displacement oscillation in the pulse tube with respect to the working gas pressure oscillation. The heating valve timing is designed to generate the working gas pressure oscillation in the pulse tube and apply a second different phase delay to the working gas displacement oscillation in the pulse tube with respect to the working gas pressure oscillation.

Abstract: A cryocooler includes a displacer capable of reciprocating in an axial direction, a cylinder that accommodates the displacer, a drive piston that drives the displacer in the axial direction, a drive chamber that accommodates the drive piston, a rotary valve that includes a first valve element that is one of a valve rotor rotatable around a rotary valve rotation axis and a valve stator, and a second valve element that is the other of the valve rotor and the valve stator, a reversible motor that is coupled with the rotary valve so as to rotate the rotary valve around the rotary valve rotation axis. The rotary valve includes a coupling mechanism that couples the first component and the second component with each other. The first relative angle is designed to cool the cryocooler, and the second relative angle is designed to heat the cryocooler.

Abstract: A cryocooler includes a first cylinder and a second cylinder, a first cooling stage, a second cooling stage, a radiation shield which is cooled by the first cooling stage, accommodates the second cooling stage, and shields the second cooling stage from radiant heat from an outside, and a temperature sensor which detects a temperature of the second cooling stage. A working gas is supplied into the first cylinder and the second cylinder to be expanded and is exhausted to the outside, an insertion hole through which an output cable of the temperature sensor passes through from an inside to an outside of the radiation shield is provided in the radiation shield, and the insertion hole is configured such that the radiant heat entering the radiation shield from the outside of the radiation shield is not directly radiated to the second cooling stage.