Abstract: A vibration free fluid compressor particularly adapted for Stirling cycle cryogenic refrigeration apparatus comprising a pair of identical opposing ferromagnetic pistons (10, 12) located in a housing (22) and between a gas spring including a sealed volume (52, 54, 60) of a working fluid such as gas under pressure. The gas compresses and expands in accordance with movement of the pistons (10, 12) to generate a compression wave which can be vented out to other apparatus, for example, a displacer unit in a Stirling cycle engine. The pistons (10, 12) are urged outwardly due to the pressure of the gas; however, a fixed electromagnetic coil assembly (56), located in the housing adjacent the pistons, is periodically energized to produce a magnetic field which interlinks the pistons (10, 12) in such a fashion that the pistons are mutually attracted to one another.

Abstract: A thermodynamic system for interchanging thermal energy with external sources or sinks while minimizing the dead volume presented to the pressure cycle is based upon a thermodynamic machine which cycles a working fluid bidirectionally through a regenerator means and at least one external heat exchanger for interchanging thermal energy with a heat source or sink. Between the thermodynamic machine and the heat exchanger is a switchable thermal energy storage system using at least one heat load capacitor and two different circulation loops through the storage system. By switching the working fluid paths through the thermal energy storage system, thermal energy is exchanged but the thermodynamic machine is isolated from the heat exchanger at least predetermined intervals during operation, and the dead space in the external device does not affect the pressure cycle of the machine.

Abstract: A thermodynamic oscillator having a displacer (5) and a piston (3) (further displacer) movable due to pressure fluctuations at the resonance frequency of the oscillator. The displacer (5) and the piston (3) are located in a working space (11, 15) which is filled with working medium and can be connected through a release valve (51, 125, 167) and a supply valve (53, 129, 169), respectively, to simple reservoir (55) filled upon working medium with an increase and a decrease, respectively, of the ambient temperature with respect to a nominal temperature. The valves (51, 53, 125, 129, 167, 169) have an opening pressure which is a function of the ambient temperature. The average pressure and the resonance frequency of the oscillator can thus be stabilized at a variable ambient temperature.The oscillator can be operated as a cold-gas engine, a hot-gas engine (motor), a heat pump or a current generator.

Abstract: Positive displacement isothermal gas cycle machinery is designed with explicit control of the heat flow between the gas, the walls of the chamber and a thermal reservoir externally of the chamber. The control is achieved by providing a large chamber wall area to chamber volume ratio through the use of bellows-like walls having a configuration that ensures during each stroke numerous heat exchanges between the working gas and the bellows-like walls. The machinery includes Stirling cycle heat pumps and motors and isothermal compressors. Significant gains in thermal efficiency, up to a factor of 2, are attainable because the largest inefficiency in all isothermal machinery is imperfect control of heat flow. A regenerator for the isothermal machinery minimizes cycle losses due to gas transfer friction, gas thermal conduction, dead volume, regenerator heat mass, regenerator heat mass thermal skin depth, and regenerator mass thermal conductivity in the gas flow direction.

Abstract: A regenerator unit arranged for mounting in the flow circuit carrying a refrigerant (helium gas) between stages of a two-stage Gifford-McMahon cryorefrigerator. The unit is housed in a sleeve extending between the expansion chamber of the first stage and the low temperature heat exchanger. A locking mechanism both suspends and seals the regenerator within the sleeve so that the regenerator cannot move either axially or radially and refrigerant cannot bypass the unit. The locking mechanism makes assembling and disassembling the unit in the refrigerator readily simple.

Abstract: A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. the second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium.

Abstract: A heat exchanger for cryosurgical instruments comprises a mantle containing individual layers of a heat exchange substance, such as a heat exchange material or a heat exchange filler, an outer jacket surrounding the mantle, a contact zone within the outer jacket for receiving cooling fluid, and a heat detector in thermal contact with the outer jacket but separated by the mantle from the cooling fluid contact zone. Each of the individual layers of heat exchange substance is positioned within the mantle a spaced distance from every other individual layer, so that these individual layers of heat exchange substance are mutually separated from one another.

Abstract: To reduce the time for regenerating self-contained cryopumps a direct connection is provided during the defrosting operation between the associated expansion space and the high-pressure gas source of the cryogenerator, to heat up the low-temperature condensation surface, while the cryogenerator continues to operate. The application is particularly to multi-stage self-contained cryopumps.

Abstract: An apparatus for condensing cryogen (e.g., helium) boil-off in a confined space such as the neck tube of a helium cryostat comprising a Joule-Thompson heat exchanger and valve disposed around a displacer-expander cryogenic refrigerator so the thermal gradient in the heat exchanger matches that of the refrigerator.

Abstract: In a cryogenic refrigerator, a refrigerant is circulated in a fluid flow path between first and second chambers by the movement of a displacer means. A slide is connected to the displacer means and reciprocated by a motor. The slide has an axial passage communicating the first and second chambers. The slide has a piston for varying the volume of gas in a third chamber during its reciprocation. The need for a separate compressor is eliminated.

Abstract: A miniature cryogenic cooling system having low microphonics and thermophonics. The apparatus includes a cold finger incorporating primary and secondary working volumes and their associated regenerative beds. Both volumes are adapted to effect cooling. A displacer reciprocates within the cold finger under the influence of push-pull pressure waves from a dual compressor assembly. The cold finger includes an arrangement for providing pneumatic cushioning of the reciprocating displacer to control displacer slamming.

Abstract: A step-type heat-exchanger particularly useful for low temperature applications comprises a housing including a thermally-conductive member partitioning its interior into first and second chambers, and a sintered spongy layer of fine thermally-conductive particles bonded to each of the two opposite faces of the thermally-conductive member so as to be exposed for direct contact with a heat-exchange fluid when introduced into each of the two chambers. Also described are a method and apparatus for making the heat-exchanger, in which method and apparatus aluminum pressure plates are applied under heat and pressure to sinter the thermally-conductive particles to form the sintered spongy layers bonded to the opposite faces of the thermally-conductive member.

Abstract: A cryogenic refrigerator of rotary type which comprises a generally cylindrical rotor and an expander formed about a first axial portion of the rotor which is used as the expander rotor, with a plurality of radial vanes for defining about the expander rotor a series of expansion compartments which vary in volume as the rotor rotates. A regenerator is provided inside or outside and about a second axial portion of the rotor adjacent to and in fluid communication with the expander compartments. A compressor supplies compressed gas to the expander compartments for adiabatic expansion accompanied by a temperature drop of the expanded gas, which is conducted through the regenerator back to the compressor.

Abstract: A split Stirling refrigerator includes a pneumatically driven displacer, the displacer is driven substantially through an entire stroke by the pressure differential across a piston element extending from the displacer. A small linear trimming motor is provided to assure proper phasing of the displacer movement with the refrigerator pressure wave, to prevent overstroke, and to assure complete stroke of the displacer.

Abstract: A refrigerator has a cold producer with a pneumatically-operated displacer for displacing a working, cold-producing gas. The pneumatic and working gas-supply control is separate from the cold producer and connected thereto by tubes having volumes less than the maximum volumes of the portions of the chamber supplied thereby.

Abstract: A cryogenic refrigeration is disclosed for operation in a first mode wherein an electrical motor reciprocates a displacer, and in a second mode wherein the displayer is reciprocated by both the motor and fluidic pressure, and in a third mode wherein the displacer is reciprocated by fluidic pressure.

Abstract: In a gas cycle refrigerator having a compressor (10), a gas expansion vessel containing a displacer (3, 37), a switch valve means (11, 12) between the vessel and the compressor, and a heat accumulator (15) between gas expansion chambers (21, 23) at both ends of the displacer within the vessel, the conduit between the switch valve means and one gas expansion chamber (21) has a resistance to gaseous cooling medium which substantially corresponds to the pressure loss in the heat accumulator so that pressure will change substantially at the same rate in both the gas expansion chambers at both ends of the displacer (21, 23) and thus will not undergo an undesirable force which may occur due to a difference in pressure between the gas expansion chambers. A compact structure of switch valve in such refrigerator is also disclosed.

Abstract: Valves for controlling process gas at the cold end of an expansion engine are fluid actuated. The actuating fluid is controlled by a solenoid actuated spool valve positioned at ambient temperature. The fluid is cooled in a thermally regenerative flow path extending between the solenoid actuated valve and the fluid actuated valve.

Abstract: A system for providing thermal energy output at intermediate levels below about 120.degree. C. uses both a conventional heat source input and an ambient heat source input to the hot and cold ends, respectively, of a Vuilleumier cycle machine. While converting thermal energy to work in both a heat engine process and a heat pump process, an intermediate working chamber integral with both processes is arranged to provide thermal output at the desired intermediate level. By maintaining the pressure ratio within predetermined limits and observing a number of temperature relationships desirably high coefficients of performance are provided with useful levels of output in a reliable system having long operating life.

Abstract: The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

Abstract: A new and improved resonant free-piston Stirling engine and method of operation employing a novel virtual rod displacer is described. A rod is secured to and reciprocally moves with the displacer within the Stirling engine and has a rod piston area formed on the end of the rod remote from the displacer with the rod piston area also being subjected to the working gas periodic pressure wave. Suitable support bearings are designed within the Stirling engine housing for reciprocatingly supporting the displacer and rod assembly within the Stirling engine with a set of opposed acting gas springs being provided to act on the displacer end and rod assembly area end of the displacer and rod assembly.

Abstract: A Stirling heat pump driven by a Stirling engine has its stroke limited under conditions of decreasing pump load. This stroke limitation is accomplished by effecting the flow of gas from the engine to the heat pump in response to a maximum piston stroke. Preferably, a valved passageway is formed in communication between the gas in the engine and the gas of the pump. The passageway is valved by a means which normally blocks the flow of gas but opens when the piston of either the pump or the engines strokes to an extreme selected position. The passageway opens into the engine and into the pump at zones so that when the valve is open the zones are at a pressure differential which will cause a flow of gas from the engine to the pump. By this means the power delivered by the heat engine portion of the machine can be made to be equal to the power absorbed by the heat pump at all conditions of heat pump temperature differential.

Abstract: A heat actuated heat pumping apparatus and process having two working chambers to provide a Vuilleumier cycle for space conditioning. The working chamber volumes are in pressure communication with each other in the vicinity of intermediate thermal exchange means in each volume equalizing the pressure between the two working volumes with one module acting as the driver for the heat pumping action of the second module. Pressure communication may be maintained through a floating piston thereby providing two different intermediate heat rejection temperature levels resulting in a four temperature level Vuilleumier heat pump. The apparatus and process of this invention reduces mechanical complexity and improved thermal exchange in a heat pump system suitable for large air conditioning applications and hot water heating as well as small refrigeration and cryogenic applications.

Abstract: In thermodynamic apparatus and methods utilizing constant volume cycling devices, substantial improvements in energy output can be gained by utilization of an integrated thermodynamic process placing regenerator efficiency in a higher regime. Displacer elements operating in phased relation to the thermodynamic cycle provide superheating and supercooling to extended opposite ends of the regenerator, to establish steady state conditions which increase the temperature ratio of the system. In turn, the pressure ratio of the thermodynamic cycle is increased and the specific energy output improved. This expansion of the capability of thermodynamic machines for working in moderate temperature ranges is further utilized with systems for achieving thermal gain for heating or cooling, utilizing ambient energy as a heat source as well.

Abstract: A compressor, pump, or alternator apparatus is designed for use with a resonant free piston Stirling engine so as to isolate apparatus fluid from the periodically pressurized working fluid of the Stirling engine. The apparatus housing has a first side closed by a power coupling flexible diaphragm (the engine working member) and a second side closed by a flexible diaphragm gas spring. A reciprocally movable piston is disposed in a transverse cylinder in the housing and moves substantially at right angles relative to the flexible diaphragms. An incompressible fluid fills the housing which is divided into two separate chambers by suitable ports. One chamber provides fluid coupling between the power diaphragm of the RFPSE and the piston and the second chamber provides fluid coupling between the gas spring diaphragm and the opposite side of the piston. The working members of a gas compressor, pump, or alternator are driven by the piston.

Abstract: A fluid-operated refrigerating machine for developing extremely low temperature by using a displacer reciprocatable within a refrigeration cylinder and a fluid-operated piston solidly connected to the displacer. A mechanical converter which converts a reciprocating motion into a rotary motion is operatively connected to the piston to limit the stroke of the piston thereby to prevent the displacer from its collision with the end walls of the refrigeration cylinder and ensure smooth operation of the displacer. For controlling gas to and from the refrigeration cylinder as well as to and from the driving chamber of the piston, a single rotary valve driven by a motor is used. In an embodiment, the rotary valve is operatively connected to the converter and thus the displacer is not only under fluid-operation but also is mechanically operated by the motor through the converter.

Abstract: A construction of a variable volume chamber that allows cycling of a working fluid to occur substantially isothermally is disclosed. The present invention provides a fixed, rigid heat conductive element within the chamber. The heat conductive element has a surface area which is large relative to that of the chamber itself. The volume of the chamber is varied by a mechanism which meshes with the heat conductive element to minimize dead volume. As a result the heat conductive element absorbs and returns heat energy to and from the working fluid in an efficient fashion, resulting in a high degree of isothermalization of the working fluid.

Abstract: The cryogenic refrigerator includes a movable displacer within an enclosure having first and second chambers of variable volume. A refrigerant fluid is circulated in a fluid path between said chambers and correlated with movement of the displacer. A spool valve controls introduction of high pressure fluid and low pressure fluid to said chambers. The displacer movement is controlled by an electric motor which has a cam for reciprocating the spool valve member.

Abstract: A hot-gas piston engine (4) has, as a compression chamber, a heat exchanger (6) which comprises a number of small pipes (7) or differently designed capillaries which protrude into the burner chamber (5) of a burner (1). In the compression phase, air in the small pipes (7), which serve as the compression chamber, is compressed and additionally heated by the burner flame, whereby the pressure increases, and the piston is driven to execute a downward movement. The scavenging then occurs in the bottom dead center region. The hot outgoing air from the engine enters burner supply line (10) and then the burner, whereby the efficiency of the plant is increased even further. The mechanical energy received at the driven shaft (11) may be used to produce electrical energy or to operate a heat pump. The upper ends of the small pipes protrude into the hot water whereby they are protected from overheating.

Abstract: A resonant free-piston Stirling engine having a new and improved start-up and control method and system. A displacer linear electrodynamic machine is provided having an armature secured to and movable with the displacer and having a stator supported by the Stirling engine housing in juxtaposition to the armature. A control excitation circuit is provided for electrically exciting the displacer linear electrodynamic machine with electrical excitation signals having substantially the same frequency as the desired frequency of operation of the Stirling engine.

Abstract: A regenerative, thermodynamic cyclic process for refrigerating machines employing a high-speed compressor. During an expansion phase, a gaseous coolant is pumped by this compressor directly out of a working volume and transferred, under compression, into an intermediate tank or into a second working volume, and during a following compression phase, the coolant is pumped by the compressor out of the intermediate tank or the second working volume, while using a reversing valve actuated to operate in synchronism with a displacer movement, and returned to the first working volume of the refrigerating machine. The expended compression work is thus recovered.

Abstract: A free piston displacer control means based on an offset axis mass attached o a crankshaft flywheel in which the rotating crankshaft reciprocates the piston displacer by driving the piston during the momentum of the stroke and by static braking at the end of each stroke at the period of maximum pressure exchange across the cooler frictional seal.

Abstract: A method and apparatus for increasing the refrigeration capacity of a displacer-expander type cryogenic refrigerator pneumatically actuated by a rotary valve by increasing the number of ports of the rotary valve to increase reciprocating speed of the displacer without increasing speed of rotation of the valve.

Abstract: The invention relates to a heat pump device comprising a pair of chambers and a plurality of elements extending within both chambers. A working fluid is disposed in both of the chambers and a displacer means is positioned in each of the chambers such that they are movable within their respective chambers. Both of the displacer means have a wall that divides their respective chambers into two zones, a regenerator material that is housed therein, a plurality of elements extending outwardly from and in proximity to the elements extending within the respective chamber, and at least one passageway communicating through each displacer means and through the respective regenerator material for the working fluid to flow therethrough between the zones. There is a drive means for reciprocably moving both of the displacer means in their respective chamber between the respective zones of the chamber.

Abstract: A miniature cryogenic system preferably operating in a manner similar to a split Stirling cycle utilizes a cold finger with a solid, low weight displacer and a stationary regenerative material external to the displacer. The regenerative material preferably surrounds the displacer and extends from a fluid inlet to a cooled end plate of a housing. The displacer has a central channel that receives an auxiliary displacer that carries a regenerative material in an internal cavity. A second fluid inlet located at the end of the housing opposite the cooled end communicates with the regenerative material held in the auxiliary displacer. The main and auxiliary displacers preferably have associated heat exchangers at their cooling ends and the cooling end of the auxiliary displacer is located to pre-cool the fluid passing from the first inlet to the cooled end plate.

Abstract: A means for producing an optimized cooler expander waveform for a closed le cryogenic cooler. The cooler displacer is driven by magnetic and spring biasing means through four repeated phases of each cycle to produce four portions of the optimized cooler waveform in which each portion takes up about 25% of the total cycle. The portions are comprised of a constant velocity in opposite direction and dwell times with smoothed corner transitions between each portion. Control means for controlling the displacer movement to produce the specific waveform may be provided by a function generator applying the desired waveform into a displacer control drive circuit which has as a second input a sensory signal of the actual position of the displacer.

Abstract: In order to use a common module cryogenic cooler with two different types thermal nights, an adapter plate is required for mounting the cooler to the sights. The plate has its two opposite sides differently machined to fit against the walls of corresponding sights, and has a central opening for a cooler mounting flange. For one sight, one side of the adapter is screwed to the sight wall and the cooler flange is inserted in the central opening. For the other sight, the other side of the adapter is inserted into a recess in the sight wall, and is retained by a retainer plate screwed to the wall. The cooler flange is inserted into the adapter plate central opening through a hole in the retainer plate.

Abstract: A pneumatic space and an expansion space are provided in a cooling head hng a double-ended piston. A fluid line from the cooler compressor feeds directly into the expansion space, and, via a fluid delay, into the pressure space. In response to the fluid pressure waves in the lines, the piston is first moved in one direction by fluid in the expansion space and in the opposite direction by fluid in the pneumatic space.

Abstract: A dual pneumatic volume means in the ambient end of a free displacer cyroic cooler to provide strong pneumatic braking and dwell times of the displacer movement at both the top dead center and bottom dead center of the displacer waveform. A second pneumatic piston is positioned between the end of the cooler housing and extends into the first pneumatic piston attached to the displacer to form a pneumatic spring volume within the first piston to accomplish the strong pneumatic braking.

Abstract: A refrigerator for operating at cryogenic temperatures which has a heat exchanger comprising a previous regenerative matrix of plastic material, the elements of which behave substantially as isothermal bodies.

Abstract: This invention comprises a cryogenic cooling device operating in the manner f a split Stirling cycle engine whereby a sinusoidal pressure-wave generator distal to a regenerator displacer piston and accompanying cylinder, individually compresses in a delayed manner and expands a contained volume of gas in an expander housing respective to regenerator displacer piston travel to bring about a cooling effect in an attached displacer housing.

Abstract: A Stirling heating pump has a working piston acting upon a compression chamber and actuated by a crank drive accommodated in a housing, and a diaphragm bellows surrounding the working piston for sealing the compression chamber from the housing and having an inner hollow communicating with the former. Pressure variations in the interior of the diaphragm bellows are compensated by a pressure throttling element arranged between the compression chamber and the inner hollow of the diaphragm bellows, and a compensating diaphragm expansible in the housing and having an inner hollow communicating with the inner hollow of the diaphragm bellows serves to form a closed flow circuit.

Abstract: The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium.

Abstract: A Stirling cycle machine in which the compressor/expander is in driving connection with a first electromagnetic unit, and in which a second electromagnetic unit is connected to the displacer and can be operated as an externally-variable control of the movements of the displacer. In one form of the invention the second unit acts as an electromagnetic damper upon movements which the displacer makes in natural response to those of the compressor. In another form of the invention the second unit positively drives the displacer and the two units are interconnected by means including a phase-shifting device whereby movements of compressor and displacer are kept of equal frequency but variable as to phase difference. Transducers sensitive to position, velocity or accelaration may improve control of the movements of compressor and displacer, and a temperature sensor associated with the "cold finger" of the displacer may further improve control of the movements of the latter.

Abstract: A displacer for low-temperature refrigerating machines having a regenerator disposed in a hollow space of the displacer, wherein the regenerator is formed at least in part of a sintered material, preferably sintered bronze spheres.

Abstract: The cryogenic refrigerator includes a movable displacer within an enclosure having first and second chambers of variable volume. A refrigerant fluid is circulated in a fluid path between said chambers by movement of the displacer. A spool valve controls introduction of high pressure fluid and low pressure fluid. The displacer movement is controlled by fluidic pressure instead of an electric motor.

Abstract: A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications comprised of a compressor section (10) centrally aligned end to end with an expansion section (12) and respectively including a reciprocating compressor piston (14) and displacer (16) radially suspended in interconnecting cylindrical housings (18, 20) by active magnetic bearings (26, 28, 30, 32) and having adjacent reduced clearance regions (82, 84, 108) so as to be in non-contacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston (14) and displacer (16) are reciprocated in their housings (18, 20) by linear drive motors (48, 52) to vary the volume of respectively adjacent compression and expansion spaces (44, 46) which contain a gaseous working fluid and a thermal regenerator (95) to effect Stirling cycle cryogenic cooling.

Abstract: The cryogenic refrigerator includes a movable displacer within an enclosure having first and second chambers of variable volume. A refrigerant fluid is circulated in a fluid path between said chambers by movement of the displacer. A spool valve controls introduction of high pressure fluid and low pressure fluid. The displacer movement, at least at top dead center and bottom dead center is controlled by an electric motor.

Abstract: Swash plate driving means for cryogenic coolers wherein multiple compress and regenerators are driven. The swash plate driving means may drive one or more compressors off one or both sides of each swash plate, and one or more regenerators may simultaneously be driven by separate swash plates. The swash plates are formed to provide flat topped and bottomed repetitive pressure waves.

Abstract: The cryogenic refrigerator includes a movable displacer within an enclosure having first and second chambers of variable volume. A refrigerant fluid is circulated in a fluid path between said chambers by movement of the displacer. A spool valve controls introduction of high pressure fluid and low pressure fluid. The displacer movement is controlled by an electric motor.