Abstract: An arrangement is disclosed for energy transformation under the utilization of an oscillating gas volume sustained by an energy supplying device. A gas compression creates an elevated temperature and a gas decompression creates a reduced temperature within the gas volume. One or more first valves are connected to the space, wherein the first valve is controllably actuatable to supply or extract thermal energy to or from the space during a compression stage. One or more second valve are further connected to the space, wherein the second valve is controllably actuatable to supply or extract thermal energy to or from the space during a decompression stage. A control unit is adapted to briefly permit actuation of the first valve and the second valve within mutually discrete time intervals.

Abstract: The invention relates to a method of regulating the temperature of an element cooled by a cryorefrigerator with periodic operation, characterized in that it comprises the following steps: (a) measuring at least the periodic temporal evolution of the temperature T of the element, this evolution making it possible to obtain a temperature signal representative of the periodic operation of the cryorefrigerator; (b) constructing a periodic so-called equivalent thermal flux signal (Soeq), as a function of the temperature signal obtained in step (a); (c) constructing a thermal flux control signal, depending on the equivalent thermal flux signal constructed in step (b), said thermal flux control signal serving also, in return, for the construction of the equivalent thermal flux signal (ScDeq, S*oeq) during step (b); (d) injecting a thermal flux into the element, on the basis of the thermal flux signal constructed in step (c), so as to compensate for the measured periodic variations of the temperature T of the element

Abstract: In a plasma processing apparatus, a check valve is installed close to a refrigerant inlet of a compressor. When performing maintenance of a sample stage, refrigerant collected from a refrigerant flow path is temporarily stored in a flow path section extending from an expansion valve to the check valve, making it possible to perform the maintenance without changing the amount of refrigerant in the refrigerating cycle. With a refrigerant storage tank, a refrigerant supply valve, and a refrigerant discharge valve included in the refrigerating cycle, when maintenance of the compressor, a condenser, or the expansion valve is performed, the refrigerant collected from the refrigerating cycle can be put in use again.

Abstract: A pulse tube refrigerator includes a compressor, a regenerator to which a refrigerant gas is discharged from the compressor and from which the refrigerant gas returns to the compressor, a pulse cube including a low-temperature end connected to the low-temperature end of the regenerator, and a flow rate controller provided at the low-temperature end of the regenerator. The flow rate controller is configured to control the flow rate of a first DC flow flowing from the regenerator toward the pulse tube and the flow rate of a second DC flow flowing from the pulse tube toward the regenerator, so that the flow rate of the first DC flow is greater than the flow rate of the second DC flow.

Abstract: A cryogenic refrigeration apparatus includes a compressor, a plurality of refrigerators, and a gas line configured to connect the plurality of refrigerators to the compressor in parallel so as to circulate a working gas between each of the plurality of refrigerators and the compressor. The gas line may include a flow rate control valve capable of individually controlling a pressure drop of a flow of working gas in a corresponding one of the plurality of refrigerators. The flow rate control valve may be provided in series with the corresponding refrigerator.

Abstract: A disclosed cryogenic refrigerator includes a first refrigerator including a compressor, a regenerator which performs intake or ejection of a refrigerant gas relative to the compressor, and a pulse tube whose low temperature end is connected to a low temperature end of the regenerator; a second refrigerator having an output smaller than the first refrigerator; a connecting pipe which performs intake and ejection of the refrigerant gas relative to a high temperature end of the pulse tube and the second refrigerator; and a flow control valve which is provided in the connecting pipe and performs a flow control of the refrigerant gas flowing inside the connecting pipe.

Abstract: A pulse tube refrigerator/cryocooler apparatus including: an inlet for receiving a cyclically moving volume of gas; a regenerator device fluidly connected to the inlet for storing and recovering thermal energy from the gas; a pulse tube fluidly connected to the regenerator; and a conduit fluidly connected at one end to the pulse tube and fluidly connected at its opposite end to a container, said container providing a storage volume for gas, wherein apparatus is configured such that the cyclically moving gas enters the regenerator in a direction parallel to its elongate axis.

Abstract: An apparatus for achieving a cryogenic temperature in a movable system, includes a rotating table, a vacuum chamber which is fixed on the rotating table, a cryogen-free refrigerator which has a cooling section inside the vacuum chamber, an inner cylinder which is fixed to a bottom of the rotating table, an outer cylinder which stores the inner cylinder such that the inner cylinder is rotatable and includes an outward and return gas port which is provided to be continuous with gas passages, a compressor which circulates gas to the cryogen-free refrigerator through the outward and return gas passages, and a rotary joint for wiring which is fixed to the inner cylinder and rotatably conducts electricity, wherein a piece of internal wiring is led through a through-hole and a hole, and electricity is supplied to a piece of equipment on the rotating table through the piece of internal wiring.

Abstract: There is provided a thermoacoustic device 1 which has in a loop tube 2, a first stack 3a between a first high-temperature side heat exchanger 4 and a first low-temperature side heat exchanger 5, and a second stack 3b provided between a second high-temperature side heat exchanger 6 and a second low-temperature side heat exchanger 7, so that heat at the first stack side is prevented from being transported to the second stack side even when a large acoustic wave is generated in the tube. In the device, self-excited standing and traveling waves are generated by heating the first high-temperature side heat exchanger 4, and by the standing and traveling waves, the second low-temperature side heat exchanger 7 is cooled. a piezoelectric film 81 is provided to suppress an acoustic streaming and/or a direct-current type flow of a working fluid.

Abstract: Vibrations of a principal machine are reduced at the fundamental and harmonic frequencies by driving the drive motor of an active balancer with balancing signals at the fundamental and selected harmonics. Vibrations are sensed to provide a signal representing the mechanical vibrations. A balancing signal generator for the fundamental and for each selected harmonic processes the sensed vibration signal with adaptive filter algorithms of adaptive filters for each frequency to generate a balancing signal for each frequency. Reference inputs for each frequency are applied to the adaptive filter algorithms of each balancing signal generator at the frequency assigned to the generator. The harmonic balancing signals for all of the frequencies are summed and applied to drive the drive motor. The harmonic balancing signals drive the drive motor with a drive voltage component in opposition to the vibration at each frequency.

Abstract: Variations of the devices and methods disclosed herein pertain to an extended travel spiral flexure bearing having spiral arms, each of the spiral arms including an attachment point at the inner end thereof and at the outer end thereof. Variations of the bearing may also include a bearing clamp to be attached to the spiral flexure bearing at the attachment points, the bearing including an outer bearing portion to be disposed on the outer periphery of the flexure bearing and an inner bearing portion to be disposed at the center of the flexure bearing. Variations also pertain to a micro check valve assembly that includes a valve base, a valve cover, and a flexure that are all bonded together. The valve being closed when the valve door rests on the valve seat and open when the valve door is lifted from the valve seat.

Abstract: A cryogenic refrigerator includes a compressor that compresses a working gas; an expansion chamber where the working gas compressed by the compressor expands and generates cooling; a valve mechanism including a stator valve and a rotor valve, which rotates with respect to the stator valve; and a forcing mechanism that applies a force to one of the rotor valve or the stator valve toward the other one of the rotor valve or the stator valve. The valve mechanism is configured to switch a flow of the working gas between the compressor and the expansion chamber as the rotor valve rotates. The forcing mechanism is arranged such that the center of the force applied by the forcing mechanism deviates from the center of the valve mechanism.

Abstract: Method for fabricating a cold finger for attachment to a base assembly of a cold head of a Stirling cycle or pulse tube cryocooler. The exterior of a titanium alloy workpiece is machined to form a cylindrical outer surface. The exterior surface of the titanium workpiece is nickel plated and then brazed to a stainless steel workpiece to form an integral body. The brazed stainless steel workpiece is machined to form it into an adapter ring for attachment to the base assembly. An intermediate segment of the titanium workpiece is machined into a cylindrical surface including removing all of the nickel plating from the intermediate segment and removing a portion of underlying titanium alloy to reduce the diameter of the titanium alloy workpiece in order to reduce the thickness of the cold finger wall. The interior of the integral body is machined to form a cylindrical interior surface.

Abstract: The present invention provides a single-stage double-acting traveling-wave thermoacoustic system, comprising three elementary units; each unit comprises a linear motor and a thermoacoustic conversion device. The linear motor comprises a cylinder and a piston; the piston can perform straight reciprocating motion in the cylinder. The thermoacoustic conversion device comprises a first heat exchanger, a heat regenerator, a second heat exchanger, a thermal buffer tube and a third heat exchanger connected in sequence, the first heat exchanger and the third heat exchanger of each thermoacoustic conversion device are connected to cylinder cavities of different linear motors respectively, forming a loop structure of a gas medium flow. The system comprises a thermal buffer tube and a third heat exchanger, making the temperature of gas medium given feedback to the cylinder cavity of another linear motor be close to the room temperature, ensuring the piston and cylinder working at room temperature.

Abstract: A cryogenic refrigerator includes a compressor that compresses a working gas; a displacer to which the working gas compressed by the compressor is supplied; a drive mechanism that includes a drive shaft and is configured to drive the displacer; a motor that drives the drive mechanism; a housing that accommodates the drive mechanism; a valve mechanism that adjusts a pressure of the working gas supplied to the displacer; a pipe that supplies the working gas from the compressor to the valve mechanism; and a branch pipe that branches out from the supply pipe and is connected to a space formed between the drive shaft and the housing.

Abstract: A closed-cycle refrigerator provides cooling to extremely low temperatures, particularly in the range of 0.5 K to 2.0 K. A 4 K pulse-tube cryocooler cold head or G-M cryocooler cold head liquefies helium in a first cooling chamber at a pressure at approximately 1 atmosphere. Liquid helium flows from the first cooling chamber, through a Joule-Thomson valve, and into a second cooling chamber under a pressure differential created by a pump. Helium vapor extracted from the second cooling chamber by the pump is routed back to the first cooling chamber to be re-condensed. This closed-cycle design provides continuous cooling below 2 K. Cryocooler cold head cold sections have no physical contact with subsequent cooling elements, such as the first and second cooling chambers to reduce vibration transfer. In some embodiments the cryocooler cold head is connected to a vacuum chamber via a vibration damping coupler to further reduce vibration transfer.

Abstract: The present invention relates to valved cryogenic refrigerators, in particular, Gifford McMahon (GM) refrigerators, and GM type pulse tube refrigerators where gas is cycled between high and low pressures by a valve mechanism that connects to an expander. Input power is reduced by use of a buffer volume which stores gas that flows to and from the warm end of the regenerator through a valve that opens and closes during the periods when the main supply and return valves are closed and is closed when the main supply and return valves are open.

Abstract: Polymeric additives are disclosed for compressor lubricants which can reduce the tendency of the lubricant to become entrained in compressed gases and be carried forward as fine dispersed droplets in compressed gas systems such as compressed air, natural gas, and compression refrigeration systems.

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.

Abstract: A container is described having a wall with a thickness defined by inner and outer surfaces, said inner surface defining an internal cavity for receiving fluid, the container having an opening through which fluid can enter/exit the container, said opening being connected to a fluid conduit at least a length of which extends through the wall in between the inner and outer surfaces thereof which exits through the inner surface to communicate with the internal cavity. Also described is a pulse tube ref rigerator/cryocooler system including such a container.

Abstract: A stirling refrigerator may include a compressing portion compressing operating fluid filling a housing by reciprocal motion of a piston, an expanding portion expanding the operating fluid compressed at the compressing portion by reciprocal motion of a piston, and a regenerating portion fluidly communicating the compressing portion with the expanding portion, and may provide heat at the compressing portion and may absorb heat at the expanding portion through repeating isothermal compression, constant-volume process and isothermal expansion of the operating fluid. The rectification unit may be adapted to uniformalize flow of the operating fluid flowing between the compressing portion and the expanding portion.

Abstract: The present invention discloses a heat-actuated double-acting traveling-wave thermoacoustic refrigeration system, comprising at least three elementary units; each elementary unit comprises a thermoacoustic engine, a thermoacoustic refrigerator, and a resonance device; the thermoacoustic engine and the thermoacoustic refrigerator comprise a main heat exchanger, a heat regenerator, a non-normal-temperature heat exchanger, a thermal buffer tube, and an auxiliary heat exchanger connected in sequence; the resonance device comprises a sealed housing, a moving part is provided in the housing for a reciprocating motion; the moving part separates the housing into at least two chambers; the main heat exchanger and auxiliary heat exchanger of each thermoacoustic engine and thermoacoustic refrigerator respectively connects to chambers of different housing, forming dual-loop structure of gas medium flow.

Abstract: In an electron paramagnetic resonance spectrometer, a closed cycle cryocooler is used to cool gaseous helium, which is then circulated around a sample to cool the sample by direct convection. Since the sample is not mechanically connected to the refrigerator, no vibrations are transmitted from the refrigerator to the sample and the sample can be quickly removed and replaced. The cooled helium can be passed through a Joule-Thomson expansion device before circulating the cooled helium around the sample to further cool the helium. In addition, a vacuum pump can be connected to the helium outlet after circulating the cooled helium around the sample to increase the pressure differential across the Joule-Thomson expansion device and further cool the helium. In order to raise the temperature of the cooled helium, a heater can be placed about the cooled helium line upstream from the sample.

Abstract: An opposed piston gamma type Stirling machine has its displacer driven by a linear electromagnetic transducer that is drivingly linked to the displacer and is located on the opposite side of the power piston's axis of reciprocation from the displacer preferably in the bounce space. The linear transducer is controlled by an electronic control as a function of sensed inputs of Stirling machine operating parameters. In addition to allowing improvements in stability and efficiency, such a Stirling machine operated as a cooler/heat pump can also be controlled so that its displacer can be driven at (1) a phase angle that pumps heat in one direction through the machine or (2) at another phase angle that pumps heat in the opposite direction through the machine and allows selectively switching between the heat pumping directions.

Abstract: A vertical support rigidly mounted to a planar base positions and supports a cryocooler expander unit off axis and away from a sample to be examined. The sample support is likewise rigidly mounted to the planar base with a rigidly mounted sample housing therein. The cryocooler expander unit is suspended in the vertical support by spring dampening bearings. A pair of opposing flexible vacuum bellows connects the cryocooler expander unit to the sample housing and vertical support. This configuration isolates the sample from vibration. Flexible thermal links associated with an predictive electronic closed loop control sequence maintains sample temperature.

Abstract: The rotary type ultralow temperature refrigerant supply apparatus includes a refrigerant introduction pipe coupled to the super conductive rotor for supplying a liquid-phase ultralow temperature refrigerant cooled by the refrigeration system to the evaporator, a refrigerant withdrawal pipe disposed spaced apart from the refrigerant introduction pipe for withdrawing a gas-phase ultralow temperature refrigerant obtained through the evaporation of the liquid-phase refrigerant by the evaporator and guiding the withdrawn gas-phase ultralow temperature refrigerant to the refrigeration system, and a vacuum housing fixedly disposed outside the refrigerant introduction pipe and the refrigerant withdrawal pipe, the vacuum housing having a vacuum heat insulation space defined inside.

Abstract: Described herein is a Stirling cycle cryogenic cooler comprising: a first magnetic circuit and a second magnetic circuit for generating a field of magnetic flux; the first magnetic circuit and the second magnetic circuit having a shared magnetic gap and the first magnetic circuit further having an additional magnetic gap; a first coil disposed in the shared magnetic gap; and a second coil disposed in the additional magnetic gap, said second coil being mounted for independent movement relative to said first coil. Also described herein is a method of cooling using the Stirling cycle cryogenic cooler.

Abstract: Systems and methods for improving the performance of dilution refrigeration systems are described. Filters and traps employed in the helium circuit of a dilution refrigerator may be modified to improve performance. Some traps may be designed to harness cryocondensation as opposed to cryoadsorption. A cryocondensation trap employs a cryocondensation surface having a high thermal conductivity and a high specific heat with a binding energy that preferably matches at least one contaminant but does not match helium. Multiple traps may be coupled in series in the helium circuit, with each trap designed to trap a specific contaminant or set of contaminants. Both cryocondensation and cryoadsorption may be exploited among multiple traps.

Abstract: A cryogenic apparatus is provided having a nested thermally insulating structure, thermal links, a vacuum shroud, and a cryo-cooler. The nested thermally insulated structure holds a sample to be cooled while dampening the external vibrations caused by the cryo-cooler, the surrounding environment or cryo-cooler mounting surface. The thermal link is made of thermally conductive wires which connect the nested thermally insulated structure and the cryo-cooler thereby allowing the apparatus to reduce vibrations inherent in the operation of the cryo-cooler.

Abstract: A regenerative cryocooler, the regenerative cryocooler being connected to a compressor configured to make coolant gas have a high pressure, send the high pressure coolant gas, and absorb coolant gas having a low pressure, the regenerative cryocooler includes a cooling stage having a regenerative material and connected to a cylinder member, the cylinder member being where the coolant gas flows, the coolant gas repeating compression and expansion; and a reinforcing member configured to prevent vibration of the cooling stage.

Abstract: In one embodiment according to the invention, there is provided a method for generating electrical energy using a thermal cycle of a working gas. The method comprises using the motion of a piston in a cylinder, containing the working gas performing the thermal cycle, to electromagnetically induce current in an electrical circuit coupled to the cylinder; using the electrical circuit to store the electrical energy, produced by the current induced in the electrical circuit, in an electrical storage device; and using the electrical energy stored in the electrical storage device to electromagnetically provide a motive force to the piston. Cyclically using the electrical circuit to store the electrical energy and using the stored energy to provide a motive force to the piston effect a net positive average power transfer into the electrical storage device over the course of the thermal cycle.

Abstract: An image sensing apparatus includes a focal plane array and a cold shield thermally isolated from the focal plane array. The cryogenic cooling apparatus further includes a first cryocooler assembly comprising a first cold finger thermally coupled to the focal plane array. The first cryocooler assembly is configured to maintain a focal plane array operating temperature. The cryogenic cooling apparatus includes a second cryocooler assembly comprising a second cold finger thermally coupled to the cold shield. The second cryocooler assembly is configured to maintain a cold shield operating temperature that is different from the focal plane array operating temperature.

Abstract: A Stirling refrigerator for a vehicle may include a drive portion receiving driving torque to be rotated, a compression portion that may be connected to the drive portion to isothermally compress operational fluid through rotation of a rotation shaft, an expansion portion that may be disposed at one side of the compression portion and isothermally expands the operational fluid that may be compressed by the compression portion through the rotation of the rotation shaft to perform an endothermic reaction, and a regeneration portion that may be disposed at one side of the expansion portion and connects the compression portion with the expansion portion such that the compressed operational fluid may be supplied to the expansion portion.

Abstract: In one embodiment according to the invention, there is provided a method for generating electrical energy using a thermal cycle of a working gas. The method comprises using the motion of a piston in a cylinder, containing the working gas performing the thermal cycle, to electromagnetically induce current in an electrical circuit coupled to the cylinder; using the electrical circuit to store the electrical energy, produced by the current induced in the electrical circuit, in an electrical storage device; and using the electrical energy stored in the electrical storage device to electromagnetically provide a motive force to the piston. Cyclically using the electrical circuit to store the electrical energy and using the stored energy to provide a motive force to the piston effect a net positive average power transfer into the electrical storage device over the course of the thermal cycle.

Abstract: A pulse tube cryocooler modulating phase via an inertance tube and an acoustic amplifier (A1, A2) provided in the pulse tube cryocooler are disclosed. The acoustic power amplifier (A1, A2) is made of a metal pulse tube (PT1, PT2) filled with regenerative materials, which are located at a distance of X from the hot end of the pulse tube. The length of the regenerative materials is L which meets the requirement of X?L>0. The acoustic power amplifier (A1, A2) can be used not only in a single-stage pulse tube cryocooler, but also in a multi-stage pulse tube cryocooler thermally coupled or gas coupled. The regenerative materials may be any cold storage materials applicable at low temperatures, such as stainless steel wire mesh, lead pellet, lead thread et al. The acoustic power amplifier (A1, A2) can increase the acoustic power at the hot end of the pulse tube (PT1, PT2), which is advantageous to the phase modulation of the inertance tube, thereby the properties of the pulse tube cryocooler can be enhanced.

Abstract: In one embodiment, a cryocooler assembly for cooling a heat load is provided. The cryocooler assembly includes a vacuum vessel surrounding the heat load and a cryocooler at least partially inserted into the vacuum vessel, the cryocooler including a coldhead. The assembly further includes an actuator coupled to the cryocooler. The actuator is configured to translate the cryocooler coldhead into thermal engagement with the heat load and to maintain constant pressure of the coldhead against the heat load to facilitate maintaining thermal engagement with the heat load as the heat load shrinks during a cool down process.

Abstract: A cryocooler assembly for cooling a field winding of an electrical machine having an axis of rotation is provided. The assembly includes a cryocooler and a reservoir coupled in flow communication to the cryocooler and configured to contain a cooling agent. A flow assembly is coupled in flow communication to the reservoir. The flow assembly includes a first flow loop coupled in flow communication to the reservoir; a second flow loop coupled in flow communication to the reservoir; and a plurality of flow members coupled in flow communication to the first flow loop and the second flow loop and coupled to the field winding. Each flow member is configured to thermosiphon the cooling agent in a first state from the reservoir and in a second state to the reservoir.

Abstract: A heat pump system including a heat engine having a valve assembly positioned to divide the heat engine chamber into a first chamber and a second chamber. A piston is positioned within the heat engine and includes a first piston head in the first chamber, a second piston head in the second chamber, and a connecting rod connecting the first and second piston heads and extending through a bore in the valve assembly. The valve assembly includes a one-way inlet valve and a one-way outlet valve in fluid communication with each of the first and second heat engine chambers. The valve assembly is also in fluid communication with a condenser and evaporator of the heat pump system. The system may also include improved one-way valves, a condensate pump, and a novel shifting valve.

Abstract: A cryocooler-based gas scrubber, or cryocooler-based gas purifier, utilizes the cooling power of a cryocooler to cool and condense cryogen gas forming coalesced impurities which are then filtered through a filter matrix, such as for example a fiberglass filter matrix. The scrubber may further comprise a counter-flow heat exchanger for warming the purified gas prior to dispensing at an outlet for storage or consumption.

Abstract: An improved free piston Stirling machine having a gamma configuration. The displacer and each piston is reciprocatable within a cylinder having an unobstructed opening at its inner end into a common volume of the workspace. The common volume is defined by the intersection of inward projections of the displacer cylinder and the piston cylinders. The displacer and the pistons each have a range of reciprocation that extends into the common volume. A displacer drive rod is reciprocatable in a drive rod cylinder and both are positioned outside the common volume and on the opposite side of the common volume from the displacer. The displacer is connected to the displacer drive rod by a displacer connecting rod. Importantly, the displacer and pistons have complementary interfacing surface contours formed on their inner ends which substantially reduces the dead volume of this gamma configured machine.

Abstract: A cryocooler for liquefying gas in which the neck of the dewar or cryostat includes a cold end of a cryocooler with the first stage cooling station, the first stage regenerator, the second stage cooling station, the second stage regenerator, and a condenser thermally coupled to the second cooling station. Radiation baffles are also present within the neck portion of the dewar between the storage portion for the dewar and the condenser, such that when the cryocooler is turned off, the radiation baffles reduce heat radiation on the cryogen in the storage section of the dewar.

Abstract: A system includes a pulse tube, a compressor configured to create pulses of fluid in the pulse tube, and a surge tank. The surge tank includes a housing that defines a surge volume configured to receive the fluid from the pulse tube. An inertance channel defines a passageway through which the fluid flows to and from the surge volume. At least part of the inertance channel has an open side to the surge volume. The surge tank also includes an adjustable seal configured to block at least part of the open side of the inertance channel and to move in order to change a functional length of the inertance channel. The housing may include a material having a high coefficient of thermal expansion, and the adjustable seal may include a material having a low coefficient of thermal expansion.

Abstract: Cryogenic cooling method and device comprising a main cryogenic cooler comprising a cold head positioned in a first chamber selectively placed under vacuum, a reservoir of working fluid placed in a second chamber selectively placed under vacuum, a member to be cooled being placed in the reservoir in heat exchange with the working fluid, the cold head of the main cryogenic cooler being thermally connected to a heat exchanger which is itself fluidically connected to the reservoir via pipes forming a first circulation loop for the working fluid, the pipes passing from the first to the second chamber, characterized in that the volumes selectively under vacuum of the first and second chambers are independent and in that the device comprises a secondary cryogenic cooler comprising a cold head placed in a third chamber selectively placed under vacuum, the cold head of the secondary cryogenic cooler being thermally connected to a heat exchanger which is itself fluidically connected to the reservoir via pipes forming

Abstract: A cryogenic refrigerator includes a displacer that is reciprocably mounted within a cylinder; a spool valve that is connected to the compressor and performs switching between an intake mode where a high-pressure refrigerant gas is supplied from the compressor to the cylinder and an exhaust mode where a low-pressure refrigerant gas within the cylinder is made to flow back to the compressor; and a drive unit that drives the spool valve. The spool valve has a valve body, and a drive rod that moves relative to the valve body and is integrated with the spool. The drive unit performs driving so that the magnitude of a speed when the drive rod moves from a top dead center to a bottom dead center is different from the magnitude of a speed when the drive rod moves from the bottom dead center to the top dead center, at the same displacement position.

Abstract: An acoustic power transmitting unit for thermoacoustic systems includes at least one stage provided with at least two thermoacoustic units each of which includes a regenerator or a stack and two heat exchangers, an acoustic resonator including a tube and containing a fluid and in which a magnetic field having high impedance and low-impedance areas is arranged, wherein certain thermoacoustic units are placed in high dimensionless impedance areas. Each high dimensionless impedance area also includes a thermoacoustic unit, wherein two successive thermoacoustic units are always separated by low dimensionless impedance. The resonator includes a reduced diameter section between each couple of successive thermoacoustic units and each cross-sectional narrowing is associated with at least one by-pass which includes a deviation cavity and makes it possible to deviate the major part of a volume flow rate.

Abstract: Embodiments of a pressurized gas supply are provided. In one embodiment, the pressurized gas supply includes a pressurized gas reservoir and a pressure reducer fluidly coupled to the pressurized gas reservoir. The pressure reducer is configured to reduce the pressure of gas received from the pressurized gas reservoir to a predetermined output pressure (PO). A gas mixture is held within the pressurized gas reservoir at a starting pressure (PS) and at a starting temperature (TS). The gas mixture includes: (i) a warming gas having a positive Joule-Thomson (JT) coefficient at TS and over the pressure range PS-PO, and (ii) a cooling gas having a negative JT coefficient at TS and over the pressure range PS-PO. The cooling of the cooling gas at least partially offsets the warming of the warming gas when the gas mixture is expelled by the isothermal gas supply to achieve a desired gas output temperature.

Abstract: A cryogenic refrigerator includes a cylinder, a displacer accommodated in the cylinder so as to reciprocate inside the cylinder with a gap formed between the periphery of the displacer and the interior surface of the cylinder, and a depressed part formed on at least one of the periphery of the displacer and the interior surface of the cylinder. The ratio of the volume of the depressed part to the volume of the gap satisfies a condition of 8?Vd/Vg?75, where Vd is the volume of the depressed part and Vg is the volume of the gap.

Abstract: A vibration control system includes a mechanical system which generates vibration; a sensor configured to measure the vibration and generate a vibration signal thereof, and a processor configured: (a) receive a vibration signal from a sensor in a mechanical system; (b) model the vibration signal using a time-domain function; (c) adjust one of an amplitude coefficient and a phase coefficient of the modeled vibration signal; (d) output a control signal corresponding to the modeled vibration signal to the mechanical system so as to reduce the vibration; and (e) receive another vibration signal from the sensor. Steps (c)-(e) are repeated when the average value of the vibration signal is greater than a predetermined value. A method for vibration control is also disclosed.

Abstract: A cryocooler, includes a cylinder filled with gas. A piston rectilinearly reciprocates inside of the cylinder and compresses or expands the gas. A connecting rod has a first side coupled to the piston and moves with the piston, and a second side having a first thread along an outer circumference thereof. A linear motor rectilinearly reciprocates a motor shaft toward the connecting rod in accordance with a control signal. A sleeve has two open sides, so that an end portion of the motor shaft can be supported by and inserted in one open side, and the second side of the connecting rod can be inserted in the other open side, and an inner circumference of the sleeve is formed with a second thread that engages with the first thread of the connecting rod and rotates to adjust a distance between the motor shaft and the connecting rod.

Abstract: LNG, for use as a motor vehicle fuel, is stored in a manner that does not require massive tanks, eliminates evaporative loss and reduces refrigeration energy consumption. A Stirling cryocooler extends through a wall of a highly insulated, relatively low pressure container to its cold end located in the vapor phase above the liquid surface. The pressure or temperature of the LNG is sensed and applied to a feedback control that modulates the heat transfer rate of the Stirling cryocooler so that LNG vapor is liquefied at a rate to maintain a desired pressure and temperature within the container. Maintaining a superatmospheric pressure in the container reduces the energy consumption required for re-liquefaction of the LNG vapor. The apparatus is also usable for liquefaction of natural gas for refueling vehicles from the ubiquitous consumer level domestic gas distribution system.