Abstract: A cryocompressor includes a check valve arranged in a circuit connecting a compression chamber defined by a piston disposed in a cylinder with an annular gap small enough to provide an expected sealing effect to a buffer chamber also defined by the piston in the cylinder, a cross sectional area of the annular gap between the piston and the cylinder being larger on the side of the compression chamber than on the side of the buffer chamber.

Abstract: A refrigerator includes a working space which is in fluid communication with a vessel of the volume-variable type with a capillary acting as a flow resistance. Each time change of the average cycle pressure in the working space is occurs, the volume of the vessel is varied so as to cancel the pressure-change. Thus, the average cycle pressure in the working space may be kept at a set value.

Abstract: When a refrigerator unit is removed, inner surfaces of a refrigeration unit housing extending into a cryogenically cooled system are heated. The method is performed in such a way as to prevent the external atmosphere from coming in contact with the housing inner surfaces, thus avoiding the problem of ice formation within the housing. A heat gun is used in conjunction with an apparatus which fits into the housing and distributes heated gas, such as nitrogen, from the heat gun to different parts of the housing in relative quantities. The inner surfaces are brought to the same temperature in the same time allowing the housing to be cleaned before the refrigeration unit is replaced. The apparatus guiding the heated gas is mounted on the outside of the housing and includes stops on its supports to keep the apparatus from making contact with the inner surfaces of the housing.

Abstract: A Stirling cycle cooling engine with separate linear motor drives for the compressor and displacer, the drives being powered by a common oscillator via respective look up table/digital to analog converter circuits and respective displacement regulating servo-loop circuits and to regulate the temperature of the element cooled by the engine, a temperature sensor arranged to control the amplitude of the compressor piston displacement.

Abstract: A regenerative heat exchanger in which a compact arrangement of alternating thermally conductive and thermally insulating solid layers have an array of communicating passages therethrough. One of the outer thermally conductive layers is heated and the other is cooled. The intermediate thermally conductive layer(s) has a regenerative function when flow is alternated through the passages. Although each passage is preferably small, the total number of passages in the array is such as to give a large combined cross-sectional area for heat transfer providing improved overall performance and efficiency when incorporated in stirling and other heat engines without sacrificing structural integrity.

Abstract: A refrigerator comprising a cold finger having an expansion space and a first compression space defined by a displacer, a regenerator connected to the expansion space and the first compression space, a cylinder having a second compression space and a buffer space defined by a piston, and a communicating tube connecting the first compression space to the second compression space. The working space thus defined is filled with the working gas so that a thermodynamic cycle can be generated in the working gas within the working space to generate coldness within the expansio space by reciprocatingly moving the piston and the displacer with a predetermined phase relationship therebetween. The refrigerator further comprises a first passage having a check valve between the working space and the buffer space, and a second connecting passage connecting the drain space and the buffer space.

Abstract: A device by which one can extract low grade thermal energy and transfer that thermal energy from one medium to another utilizing a Stirling engine compressor means, motor means, heat exchanger means and regeneration chamber. The flow of thermal energy between the two heat exchanger means utilized is reversible by the simple change in direction of rotation of the motor means.

Abstract: A cryogenic refrigeration apparatus that re-liquifies boiled off cryogenic gases and returns the cooled, re-liquified gases to the cryogenic load. Reciprocation of a driver piston effects simultaneous and corresponding reciprocation of compressor and expander pistons. A magnetic sensor senses the position of the driver piston when at its top dead center position, its bottom dead center position, and a position about half way therebetween. Signals corresponding to the sensed position of the driver piston are sent to a logic control unit that governs the opening and closing of valves throughout the apparatus.

Abstract: A modified Stirling cycle cryogenic refrigerator having a cold head, compressor and expander cylinders connected by a channel, and a compressor piston and an expander piston reciprocally mounted in the respective cylinders. A thin-walled hollow, evacuated, cylinderical metal extender is mounted on the side of the expander piston close to the cold head for shielding the expander from the low temperatures of the working gas in the vicinity of the cold head.

Abstract: A cryogenic refrigerator is disclosed having an expander piston reciprocally mounted within a fluid-tight housing. High pressure gas is supplied to a variable cold volume at one end of the piston through a passageway in the piston when the variable cold volume is at its minimum. Differential forces on the opposite end of the piston cause the piston to move, thereby enlarging the variable cold volume. The expanded cooled gas in the variable volume is vented out through the piston passageway which has been moved into fluid communication with a venting conduit when the variable volume is at its maximum. A heat exchanger operatively disposed between the gas supply and venting conduit allows the cold venting gas to cool the incoming high pressure gas.

Abstract: A gas cycle machine includes a moving coil composed of a first moving coil portion and a second moving coil portion opposing to the first moving coil portion and a magnetic circuit is constituted such that magnetic flux in a first gap in which the first moving coil portion is disposed passes through the first moving coil portion inwardly and magnetic flux in a second gap in which the second moving coil portion is disposed passes through the latter outwardly. Magnetic flux of a permanent magnet passes through the first and the second gaps in opposite directions, respectively, and, therefore, a closed magnetic circuit is composed of the permanent magnet, a cylinder of soft iron and an annular disc, which eliminates the necessity of providing a large circular disc as in the conventional engine.

Abstract: A durable low weight compressor having improved performance is disclosed. The compressor includes a fiber reinforced resin matrix composite housing and a fiber reinforced glass marix composite compression chamber liner. An air conditioner including an improved compressor is also disclosed.

Abstract: Cryogenic regenerator formed by a spirally rolled, flexible composite material including a base layer having a top and a bottom provided with a plurality of spaced, substantially parallel corrugations extending outwardly therefrom and wherein the flexible base layer is rolled into a generally cylindrical spiral with the corrugations extending radially inwardly and engaging the top of the base layer to cause the base layer and the corrugations to cooperatively form a plurality of channels for conducting the working fluid through the regenerator. The relatively flexible composite material may be a relatively flexible, hardened epoxy; the composite material may be loaded with thermally conductive material and may be an epoxy loaded with thermally conductive material.

Abstract: A technique for producing a cold environment wherein warm fluid, e.g. at room temperature, from a compressor, is introduced under pressure into an input channel which is directly coupled to a displacement volume, the fluid being precooled in the input channel to a temperature lower than that of the input fluid. Fluid in the inner channel at or near the displacement volume is periodically pressurized to a high pressure. The displacement volume is then expanded so that the high pressure fluid flowing into the expanded volume is decreased from such high pressure to a substantially lower pressure, the temperature thereof being reduced to a substantially lower temperature for producing the cold environment. The low pressure, low temperature fluid flows into an output channel, preferably via a suitable valve and surge volume, for flow in the output channel at a substantially constant pressure.

Abstract: A split Stirling cryogenic cooler including a compressor located in a first unit, and, located in a second unit, an expander-displacer defining an expansion volume, a cold tip adjacent the expansion volume, a regenerator heat exchanger and a displacer, a pneumatic conduit coupled the first unit to the second unit whereby pressurized gas pulses are provided from the compressor to the displacer for driving therof in oscillatory motion and apparatus for providing controllable damping of the resonant motion of the displacer comprising pneumatic flow produced friction damping apparatus.

Abstract: A two mass vibration isolator particularly suited to a linear reciprocating machine. Vibration into and out of the machine is attenuated by an isolator placed between the machine and its mounting frame. The isolator is an elastomer with a damping ratio of at least 0.1 sandwiched between two retainers.

Abstract: An integral cryogenic refrigerator, or cryocooler, for cooling an electronic device to cryogenic temperatures. The cryocooler has a minimum number of moving parts. A lightweight flexure link a compressor piston to a coupler which is also connected to a regenerator via a lightweight vane. An electric motor with an offset shaft drives the coupler via a bearing through a circular path to impart properly timed motion to the compressor piston and regenerator. This arrangement minimizes the weight and number of moving parts, resulting in maximum efficiency and operating life. Vibration transmission is minimized by mounting the device to be cooled on an end cap having a raised castlated rim. A reusable access port allows the cryocooler to be readily recharged.

Abstract: A heat-driven acoustic cooling engine having no moving parts receives heat from a heat source. The acoustic cooling engine comprises an elongated resonant pressure vessel having first and second ends. A compressible fluid having a substantial thermal expansion coefficient and capable of supporting an acoustic standing wave is contained in the resonant pressure vessel. The heat source supplies heat to the first end of the vessel. A first heat exchanger in the vessel is spaced-apart from the first end and receives heat from the first end. A first thermodynamic element is adjacent to the first heat exchanger and converts some of the heat transmitted by the first heat exchanger into acoustic power. A second thermodynamic element has a first end located spaced-apart from the first thermodynamic element and a second end farther away from the first thermodynamic element than is its first end. The first end of the second thermodynamic element heats while its second end cools as a consequence of the acoustic power.

Abstract: A cold finger portion of a refrigerator is coupled to a movable member by means of a spring member having a linear characteristics to form a vibration system make phase difference between pressure variation and movement of the movable member and amplitude thereof possible to set at optimum values and to make a center of movement of the movable member constant by the linearity of the spring member regardless of operating condition.

Abstract: An integral Stirling cryogenic cooler including a compressor, an expander-displacer portion defining an expansion volume, a cold tip adjacent the expansion volume, a cold tip adjacent the expansion volume, a regenerator heat exchanger and a displacer, a crank shaft arranged to receive input rotary power and to drive the compressor and the displacer, and apparatus for low vibration mounting of the expander-displacer portion with respect to the compressor.

Abstract: A cryogenic refrigerator utilizing the Gifford-McMahon cycle that includes a cylinder having a warm end and a cold end, a displacer slidably mounted within the cylinder to form an expansion chamber at the cold end of the cylinder, a regenerator housing having an inlet end connected to a source of refrigerant and an outlet end connected to said expansion chamber whereby refrigerant from said source is passed in and out of said chamber through the regenerator, and a heat exchanger for placing the warm end of the displacer cylinder in heat transfer relationship with the inlet end of the regenerator housing whereby heat energy from the warm end of the cylinder is transferred rapidly into the refrigerant as it moves out of the regenerator back to the source.

Abstract: Shell (e.g. 94) for plate-type apparatus to carry out thermo-dynamic processes based on heat exchange between flowing fluids which comprises spaced heat conductive confining plates (50a, 50b) and fluid conducting passages (56c, 56d, 56e) therebetween. At least one of the confining plates (50a, 50b) is provided with at least one diaphragm (58a, 58b) adjacent to a fluid conducting passage. The diaphragm (58a, 58b) in the confining plates (50a, 50b) ensures, in addition to heat transfer, also interactions of fluid pressures. Thus, positive circulation of fluids, operation of control valves, etc., are rendered possible by structure located within the shells themselves.

Abstract: A cryogenic refrigerator is disclosed having a displacer with a regenerator therein. The regenerator opens at one end to a warm volume and at the other end to a cold volume. The opening at the cold volume includes an end hole and a plurality of radial holes. The radial holes serve as secondary passageways should the end hole become blocked with contaminants. The life of the cryogenic refrigerator is thereby greatly enchanced.

Abstract: A refrigerating system of this invention includes at least one expansion chamber, at least one cryogenic accumulator, conduits connecting the expansion chamber and the cryogenic accumulator, and a substance to be cooled disposed between the expansion chamber and the cryogenic accumulator and in contact with one of conduits. It is a feature of this invention that a bypass conduit is disposed in parallel with one of the conduits in contact with the substance to be cooled. Thus, even when the substance to be cooled is placed away from one of the expansion chambers and one of the cryogenic accumulators, the refrigerating system of this invention can efficiently produce an extremely cold temperature of 40.degree. K. or less, and cool the substance to be cooled to a much lower temperature.

Abstract: A vehicle air conditioning system in which air or a working liquid is circulated through a heat exchanger mounted in intimate thermal contact with the cold head of a modified Stirling cycle refrigerator. The working liquid is circulated through a heat conductive tube to the location of the vehicle to be cooled. Second heat exchangers are connected to the tube at each of the locations and the air to be cooled is blown through the second heat exchangers. If air is circulated through the cold head mounted heat exchanger, the cooled air is ducted to the locations in the vehicle to be cooled.

Abstract: A pressure seal used for containing helium within a cryogenic refrigerator, which utilizes a linear drive assembly. A deformable gasket is used to seal the enclosing elements of the linear drive assembly to reduce helium leakage. Concentrically serrated members compress onto opposite sides of the soft metal gasket to form labyrinthine sealing grooves therein.

Abstract: It comprises a first cylinder (102), a displacement piston (104) sliding in the first cylinder (102), a conduit in which a thermal regenerator is included, a second cylinder (202), a second displacement piston (204) sliding in the second cylinder (202), means for displacing the first cylinder and the second cylinder in phase relation. A gas bearing (104a) is provided at the hot end of the first piston (104) and a gas bearing (104b) is provided at the intermediate temperature end of the first piston. A gas bearing (204b) is also provided at the intermediate temperature end of the second piston (204) and a gas bearing (204a) is provided at the cold end of the second piston (204).

Abstract: A saran carbon matrix is employed to conduct heat through the heat storing volume of a cryogenic regenerator. When helium is adsorbed into the saran carbon matrix, the combination exhibits a volumetric specific heat much higher than previously used lead balls. A helium adsorbed saran regenerator should allow much lower refrigerator temperatures than those practically obtainable with lead based regenerators for regenerator type refrigeration systems.

Abstract: In accordance with the invention, a hermetic refrigerant compressor pump which is used to compress helium is cooled by fins which are press fitted to the compressor's housing. The compressor is further cooled by a heat exchanger which cools oil in an oil sump located within the compressor housing. Preferably, a fan is located between the fins and the heat exchanger to help cool the pump.

Abstract: A cryogenic refrigeration system for cooling specimen, wherein an expander having one or more heat stations and a cooler at a main refrigeration circuit, which has a specimen mounting unit and is cooled at a temperature lower than the heat station, are housed in first and second vacuum chambers separate from each other, and at the second vacuum chamber is provided an open-close lid which is open to enable a specimen to be taken in or out, whereby the second vacuum chamber only is broken of its vacuum so as to enable the specimen to be exchanged.

Abstract: A cryogenic refrigerator has a working chamber defined between a cylinder and a piston received therein. The working chamber is alternately communicated with discharge and suction ports of a compressor to thereby cause a refrigerant to be repeatedly compressed and expanded. The refrigerator is provided with a sensor for detecting the pressure of the refrigerant discharged from the discharge port of the compressor. A microcomputer is connected to the sensor for making comparison between the detected pressure of the refrigerant, which is received in the form of an electric signal, and a reference value. The refrigerator is further provided with a driver circuit for controlling the drive of the motor in accordance with the result of the comparison. Accordingly, when the pressure of the refrigerant is high at the time of starting the cryogenic refrigerator, the microcomputer instructs the driver circuit to rotate a motor at high speed.

Abstract: A refrigerator has a reciprocation portion including a piston and a portion of a linear motor and having an angular resonance frequency W defined by the following equation: ##EQU1## where m=total mass of the reciprocation portionSp=area of a working surface of the pistonPa=amplitude of pressure variation of a working gas in a compression space of the refrigerator.alpha.=phase difference between a displacement of the piston and pressure variation of the working gas in the compression spaceS=stroke of the pistonKs=spring constant of a support spring of the pistonand an a.c. power source for driving the reciprocation portion, the power source has an angular frequency W.sub.o substantially equal to said angular frequency W with an acceptable error therebetween being .+-.10%.

Abstract: A linear drive motor of cryogenic refrigerator in which a reciprocating armature alternately compresses and expands a gaseous fluid in a thermodynamic cycle. An isolator system comprising a countermass, having an antiphase movement with respect to the armature is centrally mounted on unitary springs. Isolator springs are mounted between the compressor and the compressor housing such that vibrations in to and out of the system are attenuated.

Abstract: A cryogenic compressor wherein a compression space and a buffer space which are partitioned off from each other by means of a reciprocating piston are directly connected together through a passage which is provided with a check valve that allows a gas to flow only from the buffer space to the compression space and a purification chamber filled with a purifying substance. Thus, when the pressure within the compression space is about to become lower than the pressure within the buffer space, the gas is led from the buffer space to the compression space via the passage which connects these spaces directly to each other through the check valve, and even if this gas has been contaminated, it is purified by the purifying substance charged in the purification chamber and therefore the contamination of the working gas is prevented.

Abstract: This invention is comprised of an improved cryogenic refrigeration compressor which contains an externally adjustable relief valve positioned between the helium supply line and the helium return line whereby if the pressure within the helium supply line exceeds a predetermined value the externally adjustable relief valve opens up and allows helium to flow from the supply line to the return line. The relief valve is externally adjustable. It is comprised of a coaxial inlet and outlet member and externally adjustable spring compression means. Together they define a duct. Within the inlet member is a poppet valve and a spring. The spring exerts bias against the valve to close the valve against present fluid pressures.

Abstract: A linear drive motor of a cryogenic refrigerator, where a reciprocating armature which alternately compresses and expands a gaseous fluid in a thermodynamic cycle, is supported at both ends by flexure supports. The armature has a clearance seal with a stationary piston attached at one end to the armature housing by a flexible stem to minimize cross-bearing loads between the armature and the stationary piston along the clearance seal.

Abstract: Modified Stirling cycle refrigerators having a cam drive unit which is illustrated as being implemented either as a rotatable cylinder having a pair of circumferential camming grooves or as wobble plates having camming tracks on the periphery thereof. The cam drive unit drives the compressor and expander piston of the refrigerator through cam followers. Refrigerator embodiments having a plurality of compressor-expander piston pairs driven from a single cam drive are also disclosed.

Abstract: A heat machine which employs a condensing working fluid in a Stirling type mechanical arrangement. An initial mass of working fluid is contained within a closed space. Portions of hot and cold volumes are cyclically varied, which transfers a small percentage of the working fluid through large hot and cold heat exchangers interconnected with a periodic flow regenerator. With the exception of the regenerator space, the transferred working fluid is substantially in the liquid phase during the near isothermal heat rejection and compression stages, and substantially in the superheated vapor phase during the near isothermal heat addition and expansion stages. A control cylinder varies the effective mass of working fluid within the machine, so as to provide for output control. Decreasing the effective mass causes a shift in the operating cycle toward the superheated vapor region with lower mean pressure cycles, and increasing the mass causes a shift to the liquid region with higher mean pressure cycles.

Abstract: A method and apparatus for snubbing the movement of a free, gas-driven displacer in a cooling engine are disclosed. The reciprocal movement of the free, gas-driven displacer is snubbed in each direction of movement as the displacer approaches top dead center and bottom dead center of its cycle by means of a magnetic snubber. Magnetic repulsion forces are generated between the displacer and the displacer containing cylinder of the cooling engine as the displacer approaches both top dead center and bottom dead center of its cycle. Each magnetic repulsive force is non-linear with respect to the displacer and the corresponding end of the displacer containing cylinder.

Abstract: A two mass vibration isolator particularly suited to a linear reciprocating machine. Vibration into and out of the machine is attenuated by an isolator placed between the machine and its mounting frame. The isolator is an elastomer with a damping ratio of at least 0.1 sandwiched between two retainers.

Abstract: A Stirling cryogenic cooler system comprises a sealed casing, the drive for the cooler being constituted by a brushless DC motor where the stator and the driving electronics are positioned outside the casing, the rotor is transmitting rotational movement to the piston and displacer of the cooler via a crankshaft.

Abstract: A method of exchanging the displacement element of a refrigerator having a divided housing whose parts can be separated from one another in such a manner that the displacement element becomes accessible, and a refrigerator structure which facilitates the method. In order to be able to exchange the displacement element in the cold state without the danger of condensation in the displacement element chamber, a stream of protective gas is maintained during opening of the housing, during the exchange of the displacement element and during closing of the housing so that undesirable gases are unable to penetrate into the displacement element work chamber. To facilitate the method, one of the parts of the housing has the work chamber formed therein and high and low pressure gas ports are provided in this part.

Abstract: In a cryogenic split Stirling refrigerator, the compressor is driven by linear drive motors. Each linear drive motor has an armature hermetically sealed by a housing 20. Surrounding the housing is a stator formed from two bodies each housing a drive coil 48 and 49. Each body consists of two components 52-55 formed from involute laminations which have been aligned after the coil has been inserted. Separating the bodies is a magnet 56.

Abstract: In a compression piston, the wrist pin clearance bearing is lubricated by gas from the volume of working gas. The clearance bearing is formed by a wrist pin positioned within a pinhole of the piston. During reciprocation of the piston, the wrist pin oscillates in the piston pinhole and compresses the gas therein. The compression produces a squeeze film which prevents contact between the wrist pin and piston. The stroke time of the piston is not long enough during a cycle to collapse the squeeze film. The gas squeeze film thus lubricates the wrist pin clearance bearing. A clearance seal is formed between the piston and a cylinder of the piston housing. The clearance seal is of small clearance relative to the clearance bearing so that it limits leakage by the wrist pin. The small clearance seal also enables the requisite pressure buildup within the pinhole to generate an adequate squeeze film about the clearance bearing.

Abstract: A method for removing heat from a refrigeration load in a cyclically operating Gifford-McMahon refrigeration apparatus, with which in each cycle a compressed cooling gas from a high-pressure inlet is brought into heat contact with a regenerator cooled during the previous cycle and thereby cooled, the cooling gas is subsequently conveyed to a storage volume via the refrigeration load, the cooling gas is then expanded after closure of the high-pressure inlet by opening a low-pressure outlet and thereby cooled, and the cooling gas is partially conveyed by means of a displacer piston from the storage volume to the low-pressure outlet via the refrigeration load and the regenerator, refrigeration capacity hereby being transferred to the refrigeration load and the regenerator hereby being cooled.

Abstract: A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

Abstract: A cryogenic refrigeration apparatus comprises an electrically actuated compressor which supplies a working fluid to a free moving displacer which includes a regenerator matrix, so that a container in which the displacer is slidable has a cold end and an ambient temperature end. The matrix comprises a plurality of heat exchange elements which are graded lenthwise of the displacer so as to have larger surface areas adjacent the colder end of the matrix and a reduced flow resistance at the ambient end. The actuator for the compressor is responsive to signals which indicate that the displacer is at the colder end of the container and that the temperature of the colder end is above a pedetermined value.

Abstract: An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element.

Abstract: A Stirling-cycle assembly comprises an engine with a displacer piston mounted in a cylinder and defining a compression compartment and an expansion compartment respectively of a gaseous working fluid. These compartments communicate via a heat exchanger associated with a hot source, a regenerator and a heat exchanger associated with a heat sink. The engine is coupled to a heat pump having the same structure, via a resonance tube acting as an oscillatory drive member. The displacer piston of the heat pump is associated with a return means, e.g. a rod mounted in sealing-tight relationship in a closedchamber disposed on the compression compartment side.

Abstract: A cooling system has a compressor for producing cyclic pressure conditions within a refrigerator's system's volume. The compressor alternately increases and decreases the working volume, thus raising and lowering the coolant pressure. An expander reacts to this cyclic pressure change in such a manner to achieve a net removal of work, or, in the other words, provide cooling at the cold tip.