Abstract: A double inlet type pulse tube refrigerator includes a regenerator having a high temperature end and a low temperature end; a pulse tube having a high temperature end and a low temperature end connected to the low temperature end of the regenerator; a compressor having a high pressure supplying side and low pressure receiving side for a coolant, a bypass pipe having a double inlet valve, the bypass pipe being configured to connect the high temperature end of the pulse tube and the high temperature end of the regenerator; a buffer tank connected to the high temperature end of the pulse tube via a first pipe having a first flow path resistance member; and a second pipe having a second flow path resistance member including a third opening and closing valve.

Abstract: An integrated Stirling refrigerator is composed of two parts: a compressor and an expander. The compressor is composed of a shell (1), a piston (4), a leaf spring (8), a magnet (9), a coil (10), a bracket (14) and a support shelf (15). The shell (1) of the compressor includes two cylinders (11, 12), one of which is set inside the other to form a compression chamber (3). The piston (4) is connected with the leaf spring (8). The coil (10) is fixed between the inside of the shell (1) and the bracket (14), and the magnet (9) is fixed between the bracket (14) and the support shelf (15), wherein the bracket (14) and the support shelf (15) are respectively connected with the shell (1). The inside of the expander is divided into two chambers by a small piston and a regenerator (7) fixed together, that is, an expansion chamber (6) and a pneumatic chamber, and a cylindrical spring (16) is provided on the bottom of the expander.

Abstract: A sensor module for a compressor having an electric motor connected to a power supply and a processor disposed within an electrical enclosure of the compressor is provided, with the electrical enclosure being configured to house electrical terminals for connecting the power supply to the electric motor. The sensor module includes a first input connected to a voltage sensor that generates a voltage signal corresponding to a voltage of the power supply and a second input connected to a current sensor that generates a current signal corresponding to a current of the power supply. The processor is connected to the first and second inputs. The processor may calculate a power factor of the compressor, detect an unexpected variation in the power supply, and/or detect a mechanical malfunction of the compressor based on the voltage measurements and the current measurements.

Abstract: A pulse tube refrigerator includes a first pulse tube; a first regenerator connected to the first pulse tube; a compressor configured to compress the coolant gas; a first supply side valve; a first filter provided between a supply side of the first supply side valve and the high temperature end of the first regenerator; a first suction side valve connected to the first filter via a first joint point; a first self seal joint provided between the supply side of the compressor and a suction side of the first supply side valve; a second self seal joint provided between a supply side of the first suction side valve and the suction side of the compressor; and a third self seal joint provided between a first regenerator side of the first filter and the high temperature end of the first regenerator.

Abstract: A regenerative refrigerator includes a regenerator disposed in a flow passage of working gas generating a cold thermal mass, the regenerator being loaded with a regenerative material to accumulate cold thermal energy from the cold thermal mass in the working gas, wherein the regenerative material is a sintered body made of a fiber material, and a diameter of the fiber material disposed at a low-temperature end of the regenerator is smaller than a diameter of the fiber material disposed at a high-temperature end of the regenerator.

Abstract: Stirling cycle engines with hot and cold gerotor sets separated by an insulation barrier. The barrier has regenerative gas passages to allow gasses to flow therethrough thus connecting displacing chambers of the hot and cold gerotor sets. Each gerotor set has a rotor within a stator and displacing chambers created in an offset space therebetween. The stators may rotate about the rotors, or vice-versa. Either the rotor of the cold gerotor set has an axis of rotation offset with respect to the rotor of the hot gerotor set or the stator of the cold gerotor set has an axis of rotation offset with respect to the stator of the hot gerotor set, and the non-offset rotors or stators rotate about a common axis and are rotationally connected and create an angular phase offset between connected hot and cold chambers. The gerotor apparatuses may be utilized for a Stirling cycle engine for generating electricity, for example.

Abstract: An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. The piston and valves can be either mechanically or pneumatically actuated and the pressures above and below the piston can be nearly equal by virtue of a regenerator that connects the two spaces or by valves.

Abstract: A cryostat (10) is disclosed having a multistage cryocooler (20) with at least first and final cooling stages (22,32), and first and final stage heat exchangers (24,34) thermally coupled to the corresponding cooling stages for cooling a cryogen passing along a cooling path (15). The cooling path (15) further comprises a terminal cooling chamber (40) arranged to receive the cryogen from the final stage heat exchanger (34). The terminal cooling chamber (40) is also thermally coupled to the final cooling stage (32) so as to further cool the cryogen. The terminal cooling chamber (40) may include baffles (210) for directing the cryogen along an extended path through the terminal cooling chamber (40).

Abstract: Systems and methods for transferring and optionally storing and/or retrieving thermal energy are disclosed. The systems and methods generally include a heat engine and a heat pump, the heat engine including first isothermal and gradient heat exchange mechanisms, and the heat pump including second isothermal and gradient heat exchange mechanisms. The heat engine and the heat pump exchange heat with each other countercurrent across the first and second gradient heat exchange mechanisms, the first isothermal heat exchange mechanism transfers heat to an external heat sink, and the second isothermal heat exchange mechanism receives heat from an external heat source.

Abstract: A compressor device that periodically supplies compressed working gas to a cooling device loses less gas by not using a rotary valve. The compressor device includes a compressor chamber, a working gas connection, a working liquid connection, a pump, a compensation container and a membrane that is airtight and liquid-tight. The membrane divides the compressor chamber into a first volume containing a working gas and a second volume containing a working liquid. The working gas connection is coupled to the first volume, and the working liquid connection is coupled to the second volume. The pump periodically pumps the working liquid through the working liquid connection and into the second volume and as a result periodically compresses the working gas in the first volume. The membrane is constructed as a balloon or a bellows that surrounds the first volume. The compensation container contains working liquid and is connected to the pump.

Abstract: Methods are provided for creating and operating data centers. A data center may include an information technology (IT) load and a fuel cell generator configured to provide power to the IT load.

Abstract: A pulse tube refrigerator (PTR) comprising a pedestal head and a regenerator tube assembly is provided having particular application in cooling a Magnetic Resonance Imaging system. The PTR comprises a pedestal head and at least one cooled stage, the at least one cooled stage being mounted to a distal end, with respect to the pedestal head, of each of an associated regenerator tube and an associated pulse tube, the associated regenerator tube and associated pulse tube together providing pressurised coolant gas to the at least one cooled stage, wherein the associated regenerator tube and the associated pulse tube are elongate along substantially parallel axes; and further arranged, wherein, the displacements of the distal ends of each of the associated regenerator tube and the associated pulse tube in response to the cyclical changes in coolant pressure, are substantially the same when the pulse tube refrigerator is in use.

Abstract: A helium-cooling type regenerator configured to retain cold temperatures of working gas includes a first section through which the working gas flows, a second section configured to accommodate helium gas as a regenerator material, and a regenerator material pipe connected to the second section and to a helium source.

Abstract: An assembly for operating a cryocooler pedestal is provided. The assembly is operable when in use to provide a cryocooler pedestal with cyclical gaseous connection to high pressure and low pressure gas supply lines, and has a return conduit through which gas is caused to flow from the cryocooler pedestal into the low pressure supply line. The assembly further comprises a dispersion chamber adjacent the return conduit and in flow communication therewith through a plurality of orifices so as to reduce acoustic noise. The assembly has particular application in cooling a Magnetic Resonance Imaging system.

Abstract: A pressure wave generator (40) for driving one or more cryogenic refrigerator systems. The pressure wave generator (40) comprises a housing with one or more inlet/outlet ports (57,58) through which generated pressure waves of gas may pass through to drive a cryogenic refrigerator system or systems connected to the inlet/outlet ports (57,58). The pressure waves are generated by at least one pair of opposed diaphragms (41,42) located in the housing that are moveable in a reciprocating motion within the housing to create pressure waves in gas spaces (55,56) associated with each diaphragm (41,42). The gas spaces (55,56) each having associated inlet/outlet ports (57,58) through which the pressure waves may pass. An operable drive system is also provided to move the pair of diaphragms (41,42) in a reciprocating motion.

Abstract: A regenerative refrigerator includes: a regenerator unit that precools a working gas; and an expander that cools the working gas by expanding the working gas precooled by the regenerator unit. The regenerator unit includes a zinc based regenerator member formed of zinc or an alloy containing zinc as a main component of the alloy. A first stage regenerator optionally includes a high temperature part including a first regenerator member and a low temperature part including a second regenerator member different from the first regenerator member. A second stage regenerator optionally includes a high temperature part including a second regenerator member and a low temperature part including a third regenerator member different from the second regenerator member. The second regenerator member optionally includes a zinc based regenerator member formed of zinc or an alloy containing zinc as a main component of the alloy.

Abstract: This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. The objective of this invention is to keep the oil separator and absorber, which are components in an oil lubricated, helium compressor, in an indoor air conditioned environment while rejecting at least 65% of the heat from the compressor outdoors during the summer. The balance of the heat is rejected to either the indoor air conditioned air, or cooling water. This is accomplished by circulating hot oil at high pressure to an outdoor air cooled heat exchanger and returning cooled oil to the compressor inlet, while hot high pressure helium is cooled in an air or water cooled heat exchanger in an indoor assembly that includes the compressor, an oil separator, an oil absorber, and other piping and control components. It is an option to reject the heat from the oil to the indoor space during the winter to save on the cost of heating the indoor space.

Abstract: In a cryogenic refrigerator, a scotch yoke mechanism includes an eccentric rotating body and a yoke plate that reciprocates by rotation of the eccentric rotating body. A displacer is connected to a yoke plate so as to reciprocate together with the yoke plate. A cylinder houses a displacer, and an expansion space for refrigerant gas is formed in a space with the displacer. An airtight container is provided on a high-temperature side of the cylinder and includes a housing space housing a scotch yoke mechanism and receive the refrigerant gas discharged from the expansion space. The airtight container includes a supporting unit that supports a side portion of the yoke plate so as to restrict tilting of the yoke plate around a rotary shaft of the eccentric rotating body.

Abstract: Systems and methods from removing heat generated by a heat sink of a magnetic resonance imaging (MRI) system are provided. One system includes a coldhead sleeve cooling arrangement for a coldhead of the MRI system. The coldhead sleeve cooling arrangement includes a coldhead sleeve configured to receive therein a coldhead of an MRI system and a cooling system surrounding an outer surface of the coldhead sleeve. The cooling system uses helium gas to remove heat from the coldhead sleeve.

Abstract: In one embodiment, a cryocooler drive circuit for a cryocooler motor is provided that includes: a first switching power converter configured to track a first sinusoidal input voltage signal to provide a first sinusoidal output voltage signal at a first output node; and a second switching power converter configured to track a second sinusoidal input voltage signal to provide a second sinusoidal output voltage signal at a second output node, wherein the second sinusoidal input voltage signal is an inverted version of the first sinusoidal input voltage signal such that the cryocooler motor is driven by an alternating current flowing between the first and second output nodes.

Abstract: The size of a miniature cryocooler (100) operating on the Stirling refrigeration cycle is further reduced by shortening a first thermal regenerator module (R) disposed on a cold side of a thermal barrier (T) and providing a second thermal regenerator module (R1) disposed on a warm side of the thermal barrier (T). A thermally insulated fluid flow passage (172) is disposed to interconnect the first and second regenerator modules to thermally insulate the fluid passage (172). In combination, the first and second regenerator modules provide 100% thermal regenerator effectiveness in the device.

Abstract: A method for use in controlling a free piston Stirling machine having a cold end and a warm end and driven by a linear motor having an armature winding to which a drive voltage is applied. The method comprises (a) sensing internal mechanical collisions; (b) repeatedly sensing the temperature of the cold end, the temperature of the warm end and the drive voltage; (c) storing, as associated data, a value representing drive voltage, the temperature of the cold end and the temperature of the warm end at the time of sensed collisions; and (d) limiting the drive voltage to less than the drive voltage that was sensed at a collision and is stored in association with stored warm end and cold end temperatures that are proximate currently sensed warm end and cold end temperatures.

Abstract: Pulse tube refrigeration or cooling systems are described which utilize a secondary regenerator or a secondary pulse tube. Use of such a secondary regenerator or pulse tube enables a commercially available pressure oscillator to be incorporated in the cooling system. The commercially available oscillator can be operated at room temperature or approximately so.

Abstract: Apparatus and method for cooling internal components of a down-hole well drilling apparatus. Components of the well drilling apparatus are encased in an inner canister that is further encased in an outer canister creating a void between the inner canister and the outer canister. Further, a plurality of moveable barriers is disposed between the inner canister and the outer canister and contains a heat transfer fluid. A plurality of agitators add mechanical energy to the plurality of moveable barriers compressing and expanding, while repositioning, the heat transfer fluid and creating a heat pump based on a reverse Stirling cycle to remove heat from the cooler inner canister and transfer the heat to the hotter environment outside the outer canister.

Abstract: An apparatus for storing liquid air (a cryogenic mixture of about 80% liquid nitrogen and about 20% liquid oxygen) in a stable condition within a storage vessel by providing a heat exchanger in fluid communication with vaporized liquid air within vessel condense the vaporized liquid air back to liquid form. This will result in condensing the nitrogen-rich vapor into the mass as a liquid, thereby reducing ullage pressure, cooling the mass, and ultimately precluding oxygen-enrichment through boil-off. A cryocooler may be mounted externally to the vessel and in fluid communication with an interior of the vessel to condense liquid air vaporized within the vessel. The system may be used to supply air to safe haven areas of a mine or building, or piped in through a building HVAC system and/or mounted on vehicle.

Abstract: A pulse tube refrigerator has a pulse tube having a first end and a second end. A inertance tube connects the first end and a buffer tank. A pressure change generator is connected with the second end. The pressure change generator generates a pressure change of a working gas at the second end periodically. A first flow straightener provided at the first end. A second flow straightener provided at the second end. A degree to which the first flow straightener hinders the flow of the working gas is greater than a degree to which the second flow straightener hinders the flow of the working gas.

Abstract: A cryocooler is described that can include a pressure wave generator, and a refrigeration device (for example, a coldhead), which can be used to liquefy a gas when the gas is exposed to a surface of the refrigeration device. The pressure wave generator can include one or more motors. Each motor can include a stator, and at least one electrical coil wound around a portion of the stator. The electrical coil can generate a reversing magnetic field when alternating electric current is passed through the electrical coil. The motor can further include a pressurized container that can be placed within the space enclosed by the stator, and a piston that can be placed inside the pressurized container. The stators can be placed external to the pressurized container. The piston is made by combining magnets that have opposite and transverse polarities, and are combined adjacently on a common reciprocating axis.

Abstract: Pulse tube refrigeration or cooling systems are described which utilize a secondary regenerator or a secondary pulse tube. Use of such a secondary regenerator or pulse tube enables a commercially available pressure oscillator to be incorporated in the cooling system. The commercially available oscillator can be operated at room temperature or approximately so.

Abstract: A thermoacoustic engine includes a first stack and a second stack disposed in a gas-filled looped tube. The first stack has a first end to which heat is inputted and a second end to which cooling water is inputted, and the second stack has a first end to which the cooling water is inputted after passing through the second end of the first stack, and a second end provided with a cooling device. The thermoacoustic engine further includes a flow controller for controlling the flow rate of the cooling water to be inputted to the second end of the first stack.

Abstract: A pulse tube cryocooler (PTC) includes an etched glass substrate bonded to a glass plate and defining one or multiple stages or layers. The PTC includes a plurality of channels etched into a surface of the substrate to define a heat exchanger, a pulse tube, a cold heat exchanger or cold head, a regenerator and an aftercooler. The bonded substrate and plate encloses the plurality of channels to form capillaries operable for conducting and distributing fluid. The pulse tube is disposed between the cold head and the heat exchanger and the regenerator is disposed between the cold head and the aftercooler. The heat exchanger is connected to a valve or inertance tube which, in turn, is connectable to a buffer tank or reservoir that contains fluid. The aftercooler is connectable to an external compressor operable for oscillating movement, which increases and decreases pressure and temperature within the PTC.

Abstract: A low-temperature device for separating and purifying gas based on a small-sized low-temperature refrigerating machine includes a primary, secondary and quaternary heat exchanger, at least one small-sized low-temperature refrigerating machine, and at least one liquid collecting tank. The small-sized low-temperature refrigerating machine includes a first cold head and a second cold head, the secondary heat exchanger is provided on the first cold head to form a primary cold head heat exchanger, the quaternary heat exchanger is provided on the second cold head to form a secondary cold head heat exchanger, a mixed gas outlet is connected to an inlet of the primary cold head heat exchanger. By using primary and secondary cold heads of the small-sized low-temperature refrigerating machine as cold sources, gases having different condensing temperature are liquefied and solidified separately, and two or more gases can be separated and purified at a lower cost.

Abstract: A cooling system and a superconducting magnet apparatus employing the same. The cooling system includes: a thermal shield unit for thermally shielding a superconducting coil; a recondensing unit for recondensing an extremely low temperature refrigerant that cools down the superconducting coil. A cryocooler includes a body and an end portion extending from the body and inserted into the recondensing unit in order to directly contact the extremely low temperature refrigerant. A refrigerator chamber penetrates through the thermal shield unit and to which the cryocooler is attachably and detachably provided. A sealing member is disposed between the cryocooler and the refrigerator chamber to seal the recondensing unit.

Abstract: A thermoacoustic device 1 for improving heat exchange efficiency is provided which has a first stack 3a including stack constituent elements 3eL and 3eH laminated together, and a first high-temperature side heat exchanger 4 and a first low-temperature side heat exchanger 5, which are provided at two ends of the first stack 3a, in which a self-excited acoustic wave is generated by a temperature difference between the first high-temperature side heat exchanger 4 and the first low-temperature side heat exchanger 5 and is then converted to thermal energy in a stack 3b provided between a second high-temperature side heat exchanger 6 and a second low-temperature side heat exchanger 7.

Abstract: The present invention teaches providing heating elements into the nose of an intermediate distance piece of a cryogenic reciprocating pump in order to warm the piston packing seals of the pump. The heating elements increase the temperature of the piston packing seals to limit deformation of the seals while the pump is in operation. In addition, a warm, dry vapor purge may be provided to the interior of the intermediate distance piece to reduce or eliminate rime from interfering with the piston packing seals.

Abstract: The invention is directed to an improved cryogenic cooler with an expander where the regenerator matrix is decoupled from the displacer or piston, thereby allowing the design of each to be optimized substantially independently. The regenerator matrix is preferably positioned spaced apart from the displacer and can be designed to enhance thermal exchanges and flow rates of the working gas. In one embodiment, the regenerator matrix has a serpentine shape or U-shape disposed around the displacer and the cold finger. Preferably, the regenerator matrix is static. The thermal lengths of the cold finger and/or the displacer can be extended by minimizing their geometrical lengths. Additionally, the structural integrity or stiffness of the cold finger and/or displacer can be strengthened.

Abstract: A Stirling radioisotope generator is provided. The generator includes a first and second heat source assembly, each heat source assembly comprising two General Purpose Heat Source modules, each General Purpose Heat Source module configured to generate thermal energy. The generator also includes a first and second Stirling convertor in thermal communication with the first and second heat source assembly, respectively, each Stirling convertor configured to convert the thermal energy into electrical power. The generator has a housing enclosing the first and second heat source assembly and the first and second Stirling convertor, the housing configured to dissipate excess thermal energy.

Abstract: The present invention provides a Stirling engine capable of effectively recovering heat from exhaust gas flowing through a flue, and connecting a heating portion 10 and a regeneration portion 5 with each other through an operation gas tube without providing a flow passage separating portion 110, and the heating portion 10 includes a heating portion head 10a and a heat-transfer tube group, the heating portion head 10a includes first through holes 30R and second through holes 30S, the first through holes 30R are formed closer to a center region of the heating portion head 10a as compared with the second through holes 30S, one ends of U-shaped tubes are mounted in the first through holes 30R and the other ends of them are mounted in the second through holes 30S, and parallel exhaust gas flow passages is formed between the U-shaped tubes.

Abstract: A cryogenic refrigerator includes a cylinder configured to be fed with a refrigerant gas, a displacer configured to reciprocate in the cylinder, a drive unit configured to cause the displacer to reciprocate in the cylinder, and a connecting mechanism connecting the drive unit and the displacer. The connecting mechanism includes an output shaft extending from the drive unit toward the displacer, an engagement pin provided through the output shaft to extend in directions to cross the reciprocating directions of the displacer, a rotation prevention mechanism configured to engage with the engagement pin to prevent a further rotation of the displacer when the displacer rotates, and a lid body fixed to an end portion of the displacer and engaging with the output shaft.

Abstract: Disclosed is a thermoacoustic engine having: resonance pipes including a working gas; motors; and a branch pipe, where each of the motors has a regenerator, a heater, and a cooler, a temperature gradient is given between both ends of the regenerator to generate self-excited oscillation of the working gas, a channel cross-sectional area of the resonance pipe that is coupled to the heater is expanded by a same amplification factor of a work flow based on the self-excited oscillation or by an amplification factor within a range of ±30% of the amplification factor of the work flow to a channel cross-sectional area of a resonance pipe that is coupled to the cooler, and a channel cross-sectional area of the regenerator is set by 4 to 36 times of the channel cross-sectional area of the resonance pipe that is coupled to the cooler.

Abstract: A Stirling-type pulse tube refrigerator includes: a compressor which pressurizes and depressurizes a gas; a regenerator which is supplied with the gas from the compressor or supplies the gas to the compressor through pressurization or depressurization of the compressor; a pulse tube which is supplied with the gas from the regenerator or supplies the gas to the regenerator; and a flow smoother which is disposed on at least one of a high temperature side and a low temperature side of the pulse tube. The flow smoother includes a plurality of meshes arranged to be laminated and a holding member which maintains gaps between the plurality of meshes.

Abstract: A cryogenic refrigerator includes a compressor, an expansion space where a high-pressure working gas discharged from a discharge side of the compressor is caused to expand, and a valve. The valve includes a first member including a first channel connecting to the discharge side and a second member including a second channel connecting to the expansion space. The first and second members are configured to rotate relative to and in contact with each other to connect or disconnect the first and second channels. In a plane where the first and second members are in contact, a first distance that is a distance of closest approach between the first channel and a valve circumference defined by a circumference of one of the first and second members having a smaller diameter is greater than a second distance that is a distance of closest approach between the second channel and the valve circumference.

Abstract: The invention disclosed a Stirling engine regenerator, including a cylindrical regenerator cover, one end of the regenerator cover is connected with a heater and the other end is connected with a cooler. The end of the regenerator which is near the heater is provided with the first metal wire mesh, the other end of the regenerator which is near the cooler is provided with the second metal wire mesh. The regenerator is located in the cavity between the first metal wire mesh and the second metal wire mesh. The carbon fiber body filled the whole cavity. Carbon fiber body has the characteristics of high temperature resistance, high thermal conductivity and corrosion resistance and using the filling type. The manufacturing costs are very low with long service life and the contact area between the air and the carbon fiber body is large. So the heat transfer efficiency is high.

Abstract: A cryocooler assembly including a cryocooler housing and a free-piston engine arranged within the housing, an absorber housing and a damper motor arranged within the absorber housing, and a controller housing rigidly coupled between the cryocooler and the active damper such that vibrations may pass through the controller. A controller mounted within the controller housing provides power to the cryocooler and monitors the phase and frequency of the power supplied to the cryocooler. The controller monitors the vibration of the cryocooler assembly and provides a damping signal to the active damper. The damping signal generated by the controller is based at least in part on the phase and frequency of the power supplied to the cryocooler and the monitored vibration of the cryocooler assembly.

Abstract: A cryogenic refrigerator includes a compressor having a return end and a suction end that selectively connects to an expansion space, a housing having an assist space that communicates to the return end, a cylinder having one end connected to the housing and another end connected to the expansion space, a displacer that undergoes a reciprocating motion inside the cylinder, and tolerates flow of a working gas to and from the expansion space, and a drive shaft that is accommodated within the housing and drives the displacer. The drive shaft includes first and second parts having different cross sectional areas, sealed and supported by first and second seals, respectively. An end of the first part opposes the housing to form the assist space, and an end of the second part connects to the displacer.

Abstract: The present disclosure relates to improvements to thermodynamic devices that approximate the Ericsson cycle, Brayton cycle, or regenerated Brayton cycle. These cycles and various ways of implementing them are known in the art. They can operate as engines or refrigerators. The Ericsson cycle is attractive since it can theoretically operate at the Carnot efficiency, which is the maximum possible efficiency for a heat engine or refrigerator.

Abstract: A system includes a cryocooler configured to cool an object, a sensor configured to measure a temperature of the object, and a controller configured to generate an actuator drive signal to control the cryocooler based on at least one temperature measurement from the sensor. The cryocooler includes a heat exchanger and a needle configured to control flow of coolant gas through the heat exchanger. The cryocooler also includes a motion rod configured to move the needle and an actuator assembly configured to move the motion rod to thereby move the needle. The actuator could include a motor and a gear head configured to rotate a lead screw and a lead screw nut located around the lead screw and configured to translate rotational motion of the lead screw into linear motion. The actuator could also include a piezoelectric actuator or a linear actuator.

Abstract: A portable cooling unit comprising a magnetic spiral vapor pump that utilizes a magnetic pulse between two electromagnets and spiral drive slots to pull a piston back-and-forth 180-degrees and thereby alternately align compression slots on the piston's opposing ends with vapor suction ports and highly-compressed vapor discharge ports. Electromagnet use lowers the amount of battery power required for piston rotation. A condenser in a mounting pan under the pump achieves refrigerant condensation, while a fan blowing air through an evaporator positioned within a flexible hose causes cool air discharge through openings in the hose's terminal end fitting. The condenser utilizes surplus condensation from the evaporator to aid its vapor-to-liquid conversion, and batteries only provide power for the magnetic control module and fan.

Abstract: A cryogenic refrigerator includes a compressor which compresses a working gas, a housing which includes a space which the working gas compressed by the compressor flows into and flows from, a cylinder of which an end is connected to the housing and which includes an expansion space at the other end, and a displacer which permits flowing of the working gas into and from the expansion space via a working gas channel provided in an inner portion of the displacer while reciprocating in an inner portion of the cylinder. The working gas flows through a pipe which communicates with the space and the working gas channel.

Abstract: A U-shaped pulse-tube refrigerator includes a regenerative tube and a pulse-tube that are juxtaposed with each other; a communicating path that connects a low-temperature end of the regenerative tube and a low-temperature end of the pulse-tube; a heat exchanger that is provided at the low-temperature end of at least one of the regenerative tube and the pulse-tube; and a flow smoothing member that is provided between a first exit of the communicating path at a side where the heat exchanger is provided and the heat exchanger.

Abstract: An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. Low pressure on a piston drive stem provides a force imbalance to move the piston towards the warm end.