Abstract: A regenerator matrix 215 disposed in a fluid conduit 152 for exchanging thermal energy with a fluid passing through the fluid conduit. The regenerator matrix 215 has a variable fluid flow resistance and a variable capacity for convective heat transfer with the fluid along it longitudinal length. Preferably, the flow resistance and the capacity for convective heat transfer between the fluid and the regenerator matrix each increase as the fluid flows from a hot end to a cold end of the fluid conduit 152. The regenerator matrix 215 is formed from individual screen elements 50 or from stacks of screen elements sintered together as composite regenerator elements 110. A first portion 235 of the regenerator matrix made from first individual screen elements is disposed at the hot end of the regulator matrix 215. A second portion 210 of the regenerator matrix made from second individual screen elements is disposed at the cold end of the regulator matrix.

Abstract: A compact desktop gas liquefaction system having a gas generator, a cooling unit having a Stirling, pulse-tube or Stirling-pulse-tube cooler, and an insulated container to receive the liquefied gas. The system may be used to produce liquid nitrogen, oxygen, argon, natural gas, or air. The insulated container can be quickly disengaged from the gas liquefaction system, thereby minimizing the risk associated with handling liquefied gases. This compact liquefier allows for on-demand and on-site cryogen generation. The system provides a condenser surrounded by an evacuated space for greater efficiency of operation in a limited space.

Abstract: A method and apparatus for the rapid cooling of a container and its contents, such as a beverage container. A heat transfer fluid is thermally contacted with the beverage container, where the heat transfer fluid has a temperature of less than 0° C. The heat transfer fluid can be physically separated from the container, such as by flowing the heat transfer fluid through a heat exchanger that surrounds the container. The cooling parameters can be controlled such that the container and its contents are rapidly cooled without freezing of the contents.

Abstract: A hydrogen storage and delivery system is provided having an orifice pulse tube refrigerator and a liquid hydrogen storage vessel. A cooling system, coupled to the orifice pulse tube refrigerator, cools the vessel and abates ambient heat transfer thereto in order to maintain the liquid hydrogen in the vessel at or below its saturation temperature. Hydrogen boil-off, and the necessity to provide continuous venting of vaporized hydrogen are minimized or avoided. In a preferred embodiment, the hydrogen storage vessel has a toroidal shape, and the pulse tube refrigerator is a two stage pulse tube refrigerator and extends within a central void space defined at the geometric center of the toroidal storage vessel.

Abstract: When an expansion mechanism (60) having an expansion chamber (62) is equipped with a backflow prevention mechanism (80) to suppress the outflow of fluid from the expansion chamber (62) to a communication path (72), it is possible to reduce dead volume in the expansion chamber (62) during operation with the circulation control mechanism (73,75,76) closed.

Abstract: A magnetic resonance apparatus comprising a superconducting magnet coil disposed in a cryostat, and a refrigerator for cooling same comprising a compressor (1) for compressing a working gas, and a high-pressure line (2) and a low-pressure line (3) disposed between the compressor (1) and a control valve (5), which periodically connects the high-pressure line (2) and the low-pressure line (3) to at least one connecting line (6) between the control valve (5) and a cold head (4) of the refrigerator, thereby producing pressure pulses through the switched working gas, wherein the control valve (5) and/or connecting line (6) and cold head (4) components are rigidly mechanically coupled to the cryostat, is characterized in that at least one of the above-mentioned lines (2, 3, 6) is branched on the compressor side upstream of the rigidly coupled components, and is symmetrically joined at one of the coupled components in such a manner that the pressure pulses through the working gas are vectorially compensated for at t

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: A retainer and spring with threaded end are machined from a single piece of material for threading to a piston in a closed cycle cryogenic cooler. Since the machined retainer and spring are a unitary part, they cannot rub against each other during operation of the piston which reduces debris generation. The spring is preferably formed as a double start helix which further increases axial stability and reduces side loading. The spring extends into an integrally formed, threaded end at the end thereof opposite the retainer. The spring is therefore solidly connected to its adjoining parts which greatly reduces tilting and off-axis movements inherent in the prior art, wound spring designs.

Abstract: A rotary disc valve unit and refrigerators containing a rotary disc valve unit that has multiple valves, in which at least one rotary valve has ports connecting to the regenerator and at least one rotary valve has ports connecting to the warm ends of one or more pulse tubes where the rotary valve with ports for the regenerator has lighter contact than the rotary valve with ports for the pulse tubes. The valve face is divided into an inner area with ports for the pulse tubes and an outer area with ports for the regenerator, the inner area having a greater sealing pressure than the outer area.

Abstract: A thermal-cycle cryocooler, such as a Stirling-cycle cryocooler, has a single working volume that is utilized by both the compressor and the displacer. The compressor and the displacer have respective movable parts, one of which is surrounded by the other. One of the parts may be a piston, a portion of which moves within a central bore or opening in a cylinder that is the other movable part. The piston may be a component of the compressor and the cylinder may be a component of the displacer, or vice versa. The working volume is located in part in a bore of the cylinder, between the piston and a regenerator that is coupled to the cylinder. Movements of either the piston or the cylinder can directly (i.e. without the use of a gas transfer line or flow passage) cause compression or expansion of the working gas in the working volume.

Abstract: A method and mechanism for eliminating one of the magnetic circuits in a conventional two motor Stirling cryocooler. The inventive cooler is a Stirling cycle cryogenic cooler with a magnetic circuit for generating a field of magnetic flux in two separate magnetic gaps; a first coil disposed in the flux field of one gap; and a second coil disposed in the flux field of the second gap. The second coil is mounted for independent movement relative to the first coil. In a specific embodiment, the first coil is a compressor coil and the second coil is a displacer coil. The coils are energized with first and second variable sources of electrical energy in response to signals from a controller.

Abstract: A cryocooler in which two independently moving flexure systems are split across a single magnetic structure, decreasing package size and increasing resistance to cantilevered mass sag due to external forces. A series of concentrically oriented flexure coupling shafts are provided that allow two independently moving flexure assemblies to be split across a single motor. A series of connectors are included on the forward side of the motor that pass through the outer shaft and allow the inner connecting shaft to be mounted to its flexures without interference. A series of close-out connections are included on the aft flexure stacks that makes assembly possible, providing firm mechanical connections without interference.

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: 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: A fault current limiter comprising: an input node; an output node; a variable impedance element coupled between the input node and the output node; a multi-cycle refrigeration system, comprising a first coolant cycle for cooling the variable impedance element and a second coolant cycle, thermally coupled to the first coolant cycle, for cooling the first coolant, wherein the variable impedance element comprises Magnesium Diboride.

Abstract: A pulse-tube refrigerating machine includes: a compressor that pressurizes a refrigerant gas; a regenerator tube accommodating a regenerator material therein; a pulse-tube having of a hollow cylinder through which the refrigerant gas flows; an intake valve and an exhaust valve provided between the compressor and the regenerator tube. A heat-shielding material is provided to at least a portion of at least one of a first wall forming a portion of the pulse-tube and a second wall contacting a portion of the pulse-tube.

Abstract: A pulse tube cryocooler used under a non-vacuum atmosphere, the pulse tube cryocooler includes a pressure wave generator configured to generate pressure wave in an operations gas; a first stage regenerator having a high temperature end connected to the pressure wave generator; a second stage regenerator having a high temperature end connected to the first stage regenerator; a first stage pulse tube having a high temperature end and a low temperature end, the high temperature end being connected to a first buffer tank, the low temperature end being connected to a low temperature end of the first stage regenerator; a second stage pulse tube having a high temperature end and a low temperature end, the high temperature end being connected to a second buffer tank, the low temperature end being connected to a low temperature end of the second stage regenerator; a first stage cooling stage provided in a position where the first stage regenerator and the first stage pulse tube are connected; and a second stage coolin

Abstract: The cool down time for a multi-stage, pulse tube cryocooler is reduced by configuring at least a portion of the acoustic impedance of a selected stage, higher than the first stage, so that it surrounds the cold head of the selected stage. The surrounding acoustic impedance of the selected stage is mounted in thermally conductive connection to the warm region of the selected stage for cooling the acoustic impedance and is fabricated of a high thermal diffusivity, low thermal radiation emissivity material, preferably aluminum.

Abstract: A cryogenic magnet system, comprising a cryogenic vessel (1) housing a magnet winding, a vacuum jacket (3) enclosing the cryogenic vessel and a refrigerator (4) at least partially housed within the vacuum jacket and thermally linked (6) to the cryogenic vessel. In particular, the system further comprises an electromagnetic shield.

Abstract: A hydrogen storage and delivery system is provided having an orifice pulse tube refrigerator and a liquid hydrogen storage vessel. A cooling system, coupled to the orifice pulse tube refrigerator, cools the vessel and abates ambient heat transfer thereto in order to maintain the liquid hydrogen in the vessel at or below its saturation temperature. Hydrogen boil-off, and the necessity to provide continuous venting of vaporized hydrogen are minimized or avoided. In a preferred embodiment, the hydrogen storage vessel has a toroidal shape, and the pulse tube refrigerator is a two stage pulse tube refrigerator and extends within a central void space defined at the geometric center of the toroidal storage vessel.

Abstract: An improved pulse tube cooler having a resonator tube connected in place of a compliance volume or reservoir. The resonator tube has a length substantially equal to an integer multiple of ¼ wavelength of an acoustic wave in the working gas within the resonator tube at its operating frequency, temperature and pressure. Preferably, the resonator tube is formed integrally with the inertance tube as a single, integral tube with a length approximately ½ of that wavelength. Also preferably, the integral tube is spaced outwardly from and coiled around the connection of the regenerator to the pulse tube at a cold region of the cooler and the turns of the coil are thermally bonded together to improve heat conduction through the coil.

Abstract: A stationary point is set on a cold end of a cryocooler. An article is mounted on the stationary point to be cooled via the stationary point. In this case, the article can be cooled up to an extremely low temperature with isolation of vibration to the article.

Abstract: A rotary disc valve unit and refrigerators containing a rotary disc valve unit that has multiple valves, in which at least one rotary valve has ports connecting to the regenerator and at least one rotary valve has ports connecting to the warm ends of one or more pulse tubes where the rotary valve with ports for the regenerator has lighter contact than the rotary valve with ports for the pulse tubes. The valve face is divided into an inner area with ports for the pulse tubes and an outer area with ports for the regenerator, the inner area having a greater sealing pressure than the outer area.

Abstract: A cryogenic refrigerator comprising a rotary valve which controls the flow of high pressure gas into the refrigerator and the return of the gas from the refrigerator, the cryogenic refrigerator further comprising rotary fluid motor arranged to drive the rotary valve.

Abstract: The cool down time for a multi-stage, pulse tube cryocooler is reduced by configuring at least a portion of the acoustic impedance of a selected stage, higher than the first stage, so that it surrounds the cold head of the selected stage. The surrounding acoustic impedance of the selected stage is mounted in thermally conductive connection to the warm region of the selected stage for cooling the acoustic impedance and is fabricated of a high thermal diffusivity, low thermal radiation emissivity material, preferably aluminum.

Abstract: According to one embodiment, a method for improving heat transfer between a cold finger of a cryogenic cooler and a Dewar includes forming an annulus between the cold finger of the cryogenic cooler and the Dewar by inserting the cold finger into the Dewar. The cold finger has a first end and a second end. The method also includes inhibiting the formation of convective currents within the annulus in a direction between the first end and the second end. According to another embodiment of the invention, the cooling system includes a cryogenic cooler that includes a cooling section operable to generate cooling fluid and a cold finger operable to receive the cooling fluid. The cooling system also includes a Dewar formed with a void region coupled to an infrared detector. The cold finger is positioned within the void region of the Dewar creating an annulus.

Abstract: A piston compressor comprises a piston (12) which oscillates in a cylinder (14). A compressed-gas supply arrangement is provided which comprises a compressed-gas accumulator (34), a compressed-gas supply line (18) between a compressed-gas source (20) and the compressed-gas accumulator (34). Further, the compressed-gas supply line (18) comprises an inlet valve (42) which is open when the piston (12) is in a filling position. The inlet valve (42) is defined by a cylinder wall opening (22) and a piston wall opening (38) which are located opposite each other when the piston (12) is in the filling position, thus defining an open valve, and which are closed by the piston wall (40) and the cylinder wall (24), respectively, when the piston (12) is in the non-filling position, thus defining a closed valve. Thereby, a valve is provided which does not comprise any moving parts and is thus easy to manufacture, is highly reliable and has a long service life.

Abstract: Systems and methods are provided for a variable cooling capacity cryocooler for a superconducting magnetic resonance imaging device having a liquid cryogen pressure vessel to provide cryogenic temperatures to a magnet assembly, a vacuum vessel surrounding the pressure vessel and a radiation shield spaced from the cryogen pressure vessel, and a pressure sensor positioned inside the cryogen pressure vessel pressure boundary for sensing pressure variations. A controller for varying the heat removal rate of the cryocooler based on the pressure variations in the cryogen pressure vessel and where the cooling capacity of the cryocooler is adjusted by modifying the speed of the electric power drive (DC or AC motors) or by changing the mechanical transmission ratio between the constant speed electric power drive and the cryocooler displacer/piston to adjust the cooler oscillating frequency of the gas flow.

Abstract: There is provided a means for uniformly controlling the in-plane temperature of a semiconductor wafer at high speed in a high heat input etching process. A refrigerant channel structure in a circular shape is formed in a sample stage. Due to a fact that a heat transfer coefficient of a refrigerant is largely changed from a refrigerant supply port to a refrigerant outlet port, the cross sections of the channel structure is structured so as to be increased from a first channel areas towards a second channel areas in order to make the heat transfer coefficient of the refrigerant constant in the refrigerant channel structure. Thereby, the heat transfer coefficient of the refrigerant is prevented from increasing by reducing the flow rate of the refrigerant at a dry degree area where the heat transfer coefficient of the refrigerant is increased.

Abstract: The present invention is a cooling device, wherein cooling is effected by enclosing a working fluid in a conduit, which is formed by providing a looped tube formed by interconnecting both respective ends of a stack combining a hot heat exchanger with a cold heat exchanger and a stack combining a cooling heat exchanger with a cooling output heat exchanger and by providing at least one or more acoustic wave generators outside or/and inside the looped tube, and then generating a standing wave and traveling wave in the working fluid, with the present cooling device being primarily capable of markedly shortening the time until the start of generation of the standing wave and traveling wave and providing stable control.

Abstract: The refrigeration performance in a range from 3 to 10 K can be improved in comparison with conventional metal based magnetic regenerator materials. The refrigerator is provided with a regenerator utilizing at least one magnetic material including a rare earth element and sulfur as the regenerator material.

Abstract: A fibrous packing material (210) is distributed throughout the interior space of a surge tank (118). The packing material (210) makes the compression and expansion of gas within the surge tank (118) relatively more isothermal as compared to an empty tank. Thus, a smaller volume tank can be used without sacrificing performance. As a result, the size and weight requirements of the surge tank (118 ) have been reduced.

Abstract: A cylinder used for a cold head of a regenerative cryocooler, the cylinder includes an inside having a hollow-shaped configuration for a regenerative material, wherein the thickness of the cylinder at a high temperature end is greater than the thickness of the cylinder at a low temperature end.

Abstract: A cryogenic system includes a containment vessel in which a body to be cooled is housed in such a manner that the body is immersed in a liquid coolant; a tubular refrigerator sleeve; and a refrigerator, inserted in the opening section of the refrigerator sleeve, for recondensing coolant gas generated from the coolant, wherein a gas flow-forming means for forming a flow of purge gas toward an opening section of the refrigerator sleeve is provided. The purge gas prevents air from entering a refrigerator sleeve during the replacement of a refrigerator of a cryogenic system.

Abstract: A refrigerator for cooling a space inside thereof with a Stirling refrigerating engine includes state detection means for detecting an excessive cooling critical state of the Stirling refrigerating engine and excessive cooling prevention means for preventing excessive cooling of the Stirling refrigerating engine based on detection of the excessive cooling critical state by the state detection means. Excessive cooling of the Stirling refrigerating engine can thus be prevented.

Abstract: A refrigerator includes a Stirling refrigerating machine having a high-temperature heat radiation portion and a low-temperature heat absorption portion and for cooling a freezing compartment, and a compressor for circulating a first refrigerant through a first circulation circuit having a cooling compartment evaporator. The high-temperature heat radiation portion is in contact with a first circulation spiral portion formed in the first circulation circuit.

Abstract: In a regenerator to be formed by winding a resin film into a cylindrical shape, a projection is formed on a surface of the resin film by subjecting the resin film in itself to plastic deformation, either by stamping or by laser beam irradiation. Thereafter, the resin film is stacked. The projection provides a gap between layers of the stacked resin film to be a flow passage for a working gas. Thus, a regenerator of high heat exchange efficiency is provided with ease and at low cost.

Abstract: A thermoacoustic cooling system for cooling an object such as a microelectronic chip. Heat produced by the object may be transferred to a thermoacoustic engine. The thermoacoustic engine may include a resonator defining a chamber. A stack may be positioned in the chamber with one side of the stack adjacent to the heat source, and the opposite side of the stack adjacent to air in the chamber having a relatively cooler temperature. One or more orifices may be formed in the resonator such that the acoustic power generated by the thermoacoustic engine may create a synthetic jet to circulate air and move the air away from the object being cooled. A guide member may be placed in the orifice to promote circulation of air in the chamber. The heat produced by the object may be used to power the thermoacoustic engine to thereby remove heat from the object.

Abstract: A thermoacoustic device 1 for reliably generating standing and traveling waves, which have a large sound pressure, in a loop tube, has a loop tube 2 in which a working fluid is sealed; first stacks 3a, each of which has a plurality of communication paths 30 along a heat transportation direction and is provided between a first high-temperature side heat exchanger 4 and a first low-temperature side heat exchanger 5, which are provided in this loop tube 2; and a second stack 3b which has a plurality of communication paths 30 along a heat transportation direction and which is provided between a second high-temperature side heat exchanger 6 and a second low-temperature side heat exchanger 7, which are provided in the loop tube 2, and in the thermoacoustic device 1, self-excited standing and traveling waves are generated by heating the first high-temperature side heat exchanger 4, so that the second low-temperature side heat exchanger 7 is cooled by the standing and traveling waves.

Abstract: A method and an apparatus for producing hyperpolarized samples for use in magnetic resonance imaging (MRI) are provided. The apparatus comprises an ultra-compact cryogen-free cryostat structure for use in polarizing a sample of selected material, wherein the cryostat structure comprises a central bore being adapted to be evacuated to create a vacuum region, and a cooling device inserted in the central bore or optionally close to the central bore for maintaining a selected temperature of the sample.

Abstract: A regenerator material is comprised of a granular body made of bismuth or an alloy of bismuth and antimony. A rate of the granular body having a grain size of 0.14 mm to 1.6 mm is 70% by weight or more with respect to the entire granular body, and a rate of the granular body in which a ratio of a major axis to a minor axis is 5 or more is 70% by weight or more with respect to the entire granular body. Thereby, there is provided a regenerator material, more friendly to the environment, easily turned into a spherical shape, having sufficient mechanical strength for use, low cost, and having a superior thermal property when used for a cryocooler.

Abstract: A piezoelectric pump includes a casing formed of a plurality of metallic members welded and thus joined together, a piezoelectric element dividing an internal space of the casing into a working space and a back pressure space, and internal components formed of resin, and provided between the casing and the piezoelectric element and holding the piezoelectric element. The internal components are formed of workable and moldable resin. The internal component defines a perimeter of the working space and the internal component defines a perimeter of the back pressure space. The internal components are arranged opposite each other to form a recess therebetween to receive and thus hold the piezoelectric element therein.

Abstract: There is disclosed a stirling system in which a rotary-type high-temperature expansion mechanical section, a rotary-type low-temperature compression mechanical section and a driving shaft common to both the mechanical sections are stored in a sealed container to achieve remarkable simplification and improvement of durability. In the stirling system, the rotary-type high-temperature expansion mechanical section and the rotary-type low-temperature compression mechanical section for constituting a stirling cycle, and the driving shaft common to both the mechanical sections are stored in the sealed container. The sealed container is divided into a rotary-type high-temperature expansion mechanical section side and a rotary-type low-temperature compression mechanical section side by a partition wall.

Abstract: A three-stage pulse-tube cryocooler, in which the third stage pulse tube is arranged below the second stage pulse tube, with a gas flow conduit between the second stage pulse tube heat exchanger and the cold end of the second stage regenerator. The design of the invention is much simpler than a conventional three-stage parallel pulse tube cooler, requiring only two pulse tubes at the warm (room temperature) end and two reservoirs, with a corresponding reduction in the number of associated orifices, passages, etc. In effect, this provides a three stage cryocooler with a two-stage warm end design by putting the second and third stage pulse tubes in series, with a gas flow passage providing gas flow between the second and third stages for gas expansion and refrigeration. The three-stage design allows an intermediate temperature connection between the temperatures of the first and third stages, for applications which require three cooling temperatures.

Abstract: A cryostat configuration comprising an outer shell and a cryocontainer (2) for cryogenic fluid installed therein, wherein the cryocontainer (2) is connected to the outer shell via at least two suspension tubes (16), and with a neck tube (1) whose upper warm end is connected to the outer shell and whose lower cold end is connected to the cryocontainer (2) and into which a cold head (3) of a multi-stage cryocooler is installed, wherein the outer shell, the cryocontainer (2), the suspension tubes (16) and the neck tube (1) delimit an evacuated space, and wherein the cryocontainer (2) is moreover surrounded by at least one radiation shield which is connected to the suspension tubes (16) and optionally to the neck tube (1) of the cryocontainer (2) in a thermally conducting fashion, is characterized by a seal which can be manually and/or automatically actuated to separate the cold end of the neck tube (1) from the cryocontainer (2) in such a manner that fluid flow between the cryocontainer (2) and the neck tube (1)

Abstract: A piston is reciprocated axially at high speed at very small amplitude by an actuator in the larger-diameter base of an acoustic resonator. According to pressure fluctuation in the acoustic resonator involved by reciprocal motion of the piston, fluid is sucked into and discharged from the acoustic resonator via a valve device at the top end of the acoustic resonator. The acoustic resonator is contained in a gas guide. Fluid from the valve device is introduced into the gas guide to cool the valve device.

Abstract: The present invention relates to pulse tube refrigerators for recondensing cryogenic liquids. In particular, the present invention relates to the same for magnetic resonance imaging systems. In many cryogenic applications components, e.g. superconducting coils for magnetic resonance imaging (MRI), superconducting transformers, generators, electronics, are cooled by keeping them in contact with a volume of liquified gases (e.g. Helium, Neon, Nitrogen, Argon, Methane . . . ). Any dissipation in the components or heat getting into the system causes the volume to part boil off. To account for the losses, replenishment is required. This service operation is considered to be problematic by many users and great efforts have been made over the years to introduce refrigerators that recondense any lost liquid right back into the bath. The present invention addresses the problems arising from convection which occurs within a pulse tube refrigerator. The invention provides.

Abstract: A densifier is provided which in one embodiment can simultaneously densify two cryogenic liquids at different temperatures. The densifier has an oscillatory power source for generating oscillatory power and a two stage pulse tube refrigerator. The oscillatory power source can be a thermoacoustic heat engine or a mechanical oscillatory power source such as a linear flexure bearing compressor. The first stage densifies a first cryogenic liquid to a first cryogenic temperature, and the second stage densifies a second cryogenic liquid to a second, lower cryogenic temperature. A densified propellant management system also is provided which has a densifier for simultaneously densifying two cryogenic liquids at different temperatures, and a cryogenic temperature probe for measuring the temperature gradient in a cryogenic liquid.

Abstract: Method of controlling a pulse tube cryocooler in which the power input to the acoustic source is varied to maintain temperature of a refrigeration load or a temperature that is at least referable to the temperature of the refrigeration load, at a set point temperature. Additionally, the impedance of an inertance network of the pulse tube cryocooler is also adjusted to obtain a maximum cooling power to the refrigeration load at the particular temperature as sensed and the particular power that is being supplied to the acoustic source.

Abstract: A drape according to the present invention includes a sensing device and is disposed over a thermal treatment system having a basin recessed therein. A drape portion is pushed down into, and conforms to, the basin to form a drape receptacle within the basin for collecting a sterile medium. The sensing device includes electrodes that are typically disposed through the drape and sealed via patches on the non-sterile drape surface. The electrodes provide signals indicating the presence of liquid and/or leaks within the drape container to the system to facilitate control of system operation. In addition, a drape utilized for a plural basin thermal treatment system may form a drape receptacle within each basin. Each drape receptacle includes a sensing device to detect the presence of liquid and/or a leak within that drape receptacle and provide signals to the system to facilitate control of system operation.

Abstract: An alkali metal thermoelectric conversion device formed from a porous tube or plate coated with a thin film of beta-alumina, the porous tube or plate is sintered metal or metal alloy having a coefficient of thermal expansion which approaches that of the beta-alumina to form a mechanically stable device with high electrical output.