Abstract: An external combustion engine comprises a mass of compressible working fluid; a fluidic piston in fluid communication with the working fluid; and a second piston in hydraulic communication with the fluidic piston and in fluid communication with the working fluid.

Abstract: A free-piston device has a stabilized piston drift. A piston having a frequency of reciprocation over a stroke length and with first and second sides facing first and second variable volumes, respectively, for containing a working fluid defining an acoustic wavelength at the frequency of reciprocation. A bypass tube waveguide connects the first and second variable volumes at all times during reciprocation of the piston. The waveguide has a relatively low impedance for steady flow and a relatively high impedance for oscillating flow at the frequency of reciprocation of the piston, so that steady flow returns fluid leakage from about the piston between the first and second volumes while oscillating flow is not diverted through the waveguide. Thus, net leakage about the piston is returned during each stroke of the piston while oscillating leakage is not allowed and pressure buildup on either the first or second side of the piston is avoided to provide a stable piston location.

Abstract: A regenerator-based engine or refrigerator has a regenerator with two ends at two different temperatures, through which a gas oscillates at a first oscillating volumetric flow rate in the direction between the two ends and in which the pressure of the gas oscillates, and first and second heat exchangers, each of which is at one of the two different temperatures. A dead-end side branch into which the gas oscillates has compliance and is connected adjacent to one of the ends of the regenerator to form a second oscillating gas flow rate additive with the first oscillating volumetric flow rate, the compliance having a volume effective to provide a selected total oscillating gas volumetric flow rate through the first heat exchanger. This configuration enables the first heat exchanger to be configured and located to better enhance the performance of the heat exchanger rather than being confined to the location and configuration of the regenerator.

Abstract: A Stirling refrigerator, which prevents oil rising, makes oil seal bellows have long-life, and includes a housing, cylinder, piston, piston rod and an oil seal bellows. The oil seal bellows seals a space between the housing and the cylinder, wherein a tip end of the oil seal bellows is sealed and fixed on the piston or on the piston rod inside the cylinder, and a base end of the oil seal bellows is installed on the housing. The oil seal bellows reciprocates with a stroke, wherein the tip end of the oil seal bellows is compressed to a compression side from a position of free length then returns to the position of free length.

Abstract: A regenerator for a thermal cycle engine and methods for its manufacture. The regenerator has a random network of fibers formed to fill a specified volume and a material for cross-linking the fibers at points of close contact between fibers of the network. A method for manufacturing a regenerator has steps of providing a length of knitted metal tape and wrapping a plurality of layers of the tape in an annular spiral.

Abstract: A method for transmitting mechanical energy between a transfer piston of a Stirling machine and a moveable member of a generator or of an electric motor. A subject of this invention is also a device for implementing this method. The replacing of the driving piston by a completely static pneumatic resonator makes it possible not only to considerably simplify the device, since this method makes it possible to dispense with the driving piston, but also to facilitate the servocontrol as will be explained subsequently. This signifies that not only does the invention make it possible to substantially simplify the device and to reduce the production costs thereof, but also that the reliability of the device is thereby increased. However, for such a device to have an economical benefit, not only must it be possible to produce it at a competitive price, but it must also be capable of operating for many years without requiring any servicing or adjustment.

Abstract: A linear suspension element having preloaded legs that reduce fretting and maximize stroke within allowable stress limits. Also, a reciprocator and suspension including the linear suspension element.

Abstract: In a gas compressor-expander according to the invention, a partition wall 19 between a space 21 in the rear of a piston and a crank chamber 12 has a piston rod 22 slidably extending therethrough and a seal device 9 surrounding the piston rod 22. The seal device 9 comprises a first seal member 93 having a high sealing property against a flow from the crank chamber 12 toward the space 21, an intermediate chamber 91 provided in the vicinity of the first seal member 93 at one side thereof toward the space, a second seal member 95 disposed in the vicinity of the intermediate chamber 91 at one side thereof toward the space, and a communication channel 96 for holding the intermediate chamber 91 and the crank chamber 12 in communication with each other. This construction gives a prolonged life to the seal device and prevents impairment of the refrigeration capacity of the gas compressor-expander.

Abstract: An external combustion engine comprises a mass of compressible working fluid; a fluidic piston in fluid communication with said working fluid; and a second piston in hydraulic communication with said fluidic piston and in fluid communication with said working fluid.

Abstract: To provide a Stirling engine and a control unit for a Stirling engine capable of disposing a displacer unit and a power cylinder unit separately from each other, thereby increasing the degree of freedom of layout thereof. A displacer unit and a power cylinder unit of a Stirling engine E are disposed separately from each other. A compression chamber of the displacer unit is connected to an operation chamber of the power cylinder unit via a pressure conduit. A control actuator capable of arbitrarily controlling the displacer piston of the displacer unit is connected to the displacer piston.

Abstract: A pulse tube refrigerator includes a compressor, an after-cooler, a regenerating unit, a pulse tube, an inertance tube, a reservoir, and a vibration absorbing unit which are structured such that vibrations during motor operation are minimized. The vibration absorbing unit is attached with the compressor and is positioned within the reservoir, and has a fixed shaft having one end attached with a housing of the compressor, a plurality of spring plates attached to another end of the fixed shaft, and a mass body attached with the spring plates.

Abstract: The present invention discloses a miniature thermodynamic device that can be constructed using standard micro-fabrication techniques. The device can be used to provide cooling, generate power, compress gases, pump fluids and reduce pressure below ambient (operate as a vacuum pump). Embodiments of the invention relating to the production of a cooling effect and the generation of electrical power, change the thermodynamic state of the system by extracting energy from a pressurized fluid. Energy extraction is attained using an expansion process, which is as nearly isentropic as possible for the appropriately chosen fluid. An isentropic expansion occurs when a compressed gas does work to expand, and in the disclosed embodiments, the gas does work by overcoming either an electrostatic or a magnetic force.

Abstract: Electromagnetic apparatus for producing an axially directed force comprising a stator having a plurality of axially spaced coils around a working volume within which an armature in the form of a free piston is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.

Abstract: Insertion holes (3c, 4e) into which a connection pipe (9) are inserted are formed from a casing (3) to a cylinder (4). The connection pipe (9) has a flange (9a) formed on the outer periphery at a set distance from the end of the connection pipe (9). With the flange (9a) in contact with the wall outer surface of the casing (3), the end part of the connection pipe (9) is inserted into the insertion holes (3c, 4e). Between the flange (9a) and the wall outer surface of the casing (3), an O-ring (01) is fit so as to surround an internal passage (9f) of the connection pipe (9). Another O-ring (02) is fit between the end part of the connection pipe (9) and the insertion hole (4e) of the cylinder (4).

Abstract: Systems and methods for regulating, for example, the temperature of high temperature superconducting (HTSC) thin film filters used in connection with a Stirling cycle cryocooler. The system employs a digital signal processor-based control system. The system includes a cryocooler drive control loop for controlling the cryocooler drive in response to a measured cryocooler driving current and a cryocooler driving current set point. The system also includes a temperature control loop for generating the cryocooler driving current set point in response to either a cooldown profile algorithm or a comparison between a measured temperature and a set point temperature stored in DSP memory.

Abstract: A double inlet passage 70 connects a compressor 40 to remote end 53 of a vortex tube 51 that serves as the heat-rejecting heat exchanger of an orifice pulse tube refrigerator. Double inlet passage 70 includes means 3 for controlling DC flow in that passage. Fluid flows between compressor and reservoir enhance heat-rejecting effectiveness of vortex tube 51.

Abstract: In a pulse tube refrigerator the refrigeration efficiency has been improved by reducing the on-off valve loss. A second space 47 in a cylinder member 41 is connected with a second high pressure on-off valve 23 and a second low pressure on-off valve 24. A buffer side on-off valve 25 is provided between the buffer space (a buffer tank 50) and the second space 47. By opening the buffer side on-off valve 25 before the second high pressure on-off valve 23 or the second low pressure on-off valve 24 is open, the pressure in the second space 47 can be the intermediate pressure. Since the pressure difference when the valves are open is decreased, the on-off valve loss can be decreased.

Abstract: A piston includes a circumferential groove having a seal ring and spring mounted within the groove. The spring exerts an axial force on the seal ring thereby preventing motion of the seal ring within the groove. Preferably, the spring in a wave spring, wherein small changes in deflection of the wave spring produces small changes in the load generated by the spring on the seal ring. The seal ring has at least one radial spring ring mounted within the seal ring to create a radial force on the seal ring. The piston can also include a sleeve that mounts to the piston body, the sleeve forming a wall of the groove. The piston can be a displacer mounted within a cylinder of a refrigerator.

Abstract: A pulse tube expander includes a regenerator, a pulse tube, a porous plug phase shifter, and a surge tank, in series gaseous communication with each other. The porous plug phase shifter is made of a porous material such as a sintered mass or a packed solid bed of distinct, free-flowing bodies. The porous plug phase shifter introduces a phase shift between the pressure wave and the mass flow rate in the pulse tube expander. The porous plug phase shifter is resistant to clogging due to contamination that may be present in the system.

Abstract: A stirling cycle engine whose cylinder, including a mount, can be easily fabricated and securely attached. The stirling cycle engine of the invention comprises a casing having a cylindrical portion 2; a metallic cylinder 7 coaxially inserted into the cylindrical portion 2 of the casing 1; a piston 15 inserted into the cylinder 7; a drive mechanism 16 for reciprocally driving the piston 15; and a mount 28 which is attached to an outer periphery of the cylinder 7 for fixing the cylinder 7 to the casing 1 and retaining the drive mechanism 16. The mount 28 is made of a material of low heat conductance, constructed separately from the cylinder 7. The mount 28 is attached to the outer periphery of the cylinder 7. Thus, the easier working thereof is resulted, so that the working time is shortened, to thereby improve productivity, and reduce working costs. Further, The heat from the drive mechanism 16 is less likely to transfer to the cylinder 7 via the mount 28.

Abstract: A pulse tube refrigerator includes a compressor, a first heat exchanger, a first regenerator, a first cold head, a first pulse tube, a first radiator, a second regenerator, a second cold head, a second pulse tube, a second radiator, an orifice and a buffer tank which are connected in series. A first cooling part consists of the first heat exchanger, the first regenerator, the first cold head, the first pulse tube and the first radiator. A second cooling part consists of the first radiator, the second regenerator, the second cold head, the second pulse tube and the second radiator. The first radiator forms not only the radiator of the first cooling part, but also the heat exchanger of the second cooling part.

Abstract: A microscalable thermal control module consists of a Stirling cycle cooler that can be manipulated to operate at a selected temperature within the heating and cooling range of the module. The microscalable thermal control module is particularly suited for controlling the temperature of devices that must be maintained at precise temperatures. It is particularly suited for controlling the temperature of devices that need to be alternately heated or cooled. The module contains upper and lower opposing diaphragms, with a regenerator region containing a plurality of regenerators interposed between the diaphragms. Gaps exist on each side of each diaphragm to permit it to oscillate freely. The gap on the interior side one diaphragm is in fluid connection with the gap on the interior side of the other diaphragm through regenerators. As the diaphragms oscillate working gas is forced through the regenerators.

Abstract: A component for use in pulse tube cryorefrigerators which integrates the reservoirs (buffer volumes) as well as the housing for the rotary valve and valve plate and drive motor into a convenient, unified assembly. Other components required by the pulse-tube refrigerators, such as the heat sink, orifices, phase shifting valves, connecting tubing, etc., may also be integrated into the buffer volume/valve/motor housing within the teachings of the invention.

Abstract: A pulse tube system especially useful for producing and delivering refrigeration at very cold temperatures wherein a product fluid such as hydrogen is preferably precooled and then liquefied, subcooled and/or densified by heat exchange with ultra cold gas generated by a pulsing compression wave which rejects heat into a cryogen fluid heat sink.

Abstract: A heat engine is constructed from sheet metal and the like. The heat engine has an outer container and inner container which contains a displacer and a power piston. A plurality of positioning members are provided to dimensionally stabilize the inner and outer containers. By providing positioning members that extend between the inner and the outer containers, a sandwiched construction is obtained which allows the inner and outer containers to reinforce each other thus permitting the use of thin walled containers and improving the thermal efficiency of the heat engine and decreasing the weight of the heat engine.

Abstract: A heat engine is constructed from sheet metal and the like. The heat engine has an outer container and inner container which contains a displacer and a power piston. A plurality of positioning members are provided to dimensionally stabilize the inner and outer containers. By providing positioning members that extend between the inner and the outer containers, a sandwiched construction is obtained which allows the inner and outer containers to reinforce each other thus permitting the use of thin walled containers and improving the thermal efficiency of the heat engine and decreasing the weight of the heat engine.

Abstract: A hybrid two-stage cryocooler includes a first-stage Stirling expander having a first-stage interface and a Stirling expander outlet, a thermal-energy storage device in thermal communication with first-stage interface, and a second-stage pulse tube expander with a pulse tube inlet. A gas flow path extends between the Stirling expander outlet and the pulse tube inlet, and a heat exchanger is in thermal contact with the gas flow path. The relative cooling power of the first and second stages may be controlled to increase the cooling power of the second stage relative to the first stage in response to an increased heat load to the second stage. The thermal-energy storage device acts as a thermal buffer during this period, and is later cooled when the relative cooling power is adjusted to increase the cooling power of the first stage.

Abstract: Thermal machines are known in prior art. They generally differ considerably from the theoretically most advantageous engine in respect of pressure-volume cycles or have a complicated structure. The object of the present invention is to eliminate these drawbacks and achieve a new type of thermal machine. The advantages of the invention include a nearly ideal phasing of pressure-volume cycles, built-in power regulation and insignificant mechanical losses. This is achieved by using inversely linked connecting rods (9), four-chamber cylinders and a crankshaft (7) provided with rolling contact bearings with insertable rolling elements.

Abstract: A heat engine is constructed from sheet metal and the like. The heat engine has an outer container and inner container which contains a displacer and a power piston. A plurality of positioning members are provided to dimensionally stabilize the inner and outer containers. By providing positioning members that extend between the inner and the outer containers, a sandwiched construction is obtained which allows the inner and outer containers to reinforce each other thus permitting the use of thin walled containers and improving the thermal efficiency of the heat engine and decreasing the weight of the heat engine.

Abstract: A heat engine is constructed from sheet metal and the like. The heat engine has an outer container and inner container which contains a displacer and a power piston. A plurality of positioning members are provided to dimensionally stabilize the inner and outer containers. By providing positioning members that extend between the inner and the outer containers, a sandwiched construction is obtained which allows the inner and outer containers to reinforce each other thus permitting the use of thin walled containers and improving the thermal efficiency of the heat engine and decreasing the weight of the heat engine.

Abstract: A method for controlling the fuel-air ratio of a burner having a blower responsive to a blower drive signal for injecting air into the burner. The method is based at least on the concentration of a gas in an exhaust gas product of a combustion chamber of the burner and includes measuring the gas concentration in the exhaust gas product, deriving a gas concentration signal from the measured gas concentration, determining the fuel-air ratio from the gas concentration signal and the sign of the derivative of the gas concentration signal with respect to the blower drive signal, and controlling the fuel-air ratio by adjusting the air flow rate into the burner. The burner may be, for example, in a Stirling cycle engine.

Abstract: In a pulse tube refrigerator the refrigeration efficiency has been improved by reducing the on-off valve loss. A second space 47 in a cylinder member 41 is connected with a second high pressure on-off valve 23 and a second low pressure on-off valve 24. A buffer side on-off valve 25 is provided between the buffer space (a buffer tank 50) and the second space 47. By opening the buffer side on-off valve 25 before the second high pressure on-off valve 23 or the second low pressure on-off valve 24 is open, the pressure in the second space 47 can be the intermediate pressure. Since the pressure difference when the valves are open is decreased, the on-off valve loss can be decreased.

Abstract: A heat engine is constructed from sheet metal and the like. The heat engine has an outer container and inner container which contains a displacer and a power piston. A plurality of positioning members are provided to dimensionally stabilize the inner and outer containers. By providing positioning members that extend between the inner and the outer containers, a sandwiched construction is obtained which allows the inner and outer containers to reinforce each other thus permitting the use of thin walled containers and improving the thermal efficiency of the heat engine and decreasing the weight of the heat engine.

Abstract: A heat engine uses magnetic fields to hold at least one of the displacer and the piston in position and to move the at least one of the displacer and the piston.

Abstract: A heat-regenerating type cryogenic cooling apparatus 101 includes a cryogenic temperature generating part 10 having a heat regenerator 11; and a pressure generating device 30 connected to the part 10, generating pressure vibration of a working gas therein, and having a compressor 31 with a discharging port 31a and a sucking port 31b, a high-pressure line 32 whose one end is in fluid communication with the discharging port 31a of the compressor 31, a low-pressure line 33 whose one end is in fluid communication with the sucking port 31b of the compressor 31, a high-pressure open/close valve 34 connected to the other end of the line 32, a low-pressure open/close valve 35 connected to the other end of the line 33, a high-pressure side line 36 connecting the valve 34 and the 10, a low-pressure side line 37 connecting the valve 35 and the part 10, and a high-pressure side buffer tank 38 as a high-pressure source connected to the midportion of the line 32.

Abstract: An apparatus has a heat engine and a power output member drivenly connected to the piston of the heat engine and having an output for supplying work. The displacer is driven by an adjustable drive member. An adjustable signal generator is provided for modulating a signal which is sent to the adjustable drive to adjust the frequency of the displacer.

Abstract: A heat engine is constructed from sheet metal and the like. The heat engine has an outer container and inner container which contains a displacer and a power piston. A plurality of positioning members are provided to dimensionally stabilize the inner and outer containers. By providing positioning members that extend between the inner and the outer containers, a sandwiched construction is obtained which allows the inner and outer containers to reinforce each other thus permitting the use of thin walled containers and improving the thermal efficiency of the heat engine and decreasing the weight of the heat engine.

Abstract: The present invention relates to a pulse tube refrigerator comprising a compressor for compressing operating gas while a piston performs a linear reciprocating motion inside of a cylinder by receiving the operating force of an operating motor installed inside of a housing, a after-cooler connected with the compressor, a regenerating unit connected with the after-cooler, a reservoir formed so as to be one-bodied to a pulse tube connected with the regenerating unit or a sealed casing or a housing, a vibration absorbing unit for reducing the vibration occurred by the operation of the operating motor by being fixedly combined to the sealed casing or a sealing member of the housing, the sealing member for improving the efficiency of the vibration absorbing unit combined between the housing and reservoir, and an inertance tube formed so as to surround the outer circumference of the pulse tube and reservoir in order to connect the pulse tube and reservoir.

Abstract: A refrigeration apparatus driven by a Stirling cooler and having reduced internal vibrations. The apparatus may include an insulated enclosure. The enclosure may define an opening from the inside to the outside. A heat-conducting member may be disposed within the enclosure and in alignment with the opening. The apparatus may further include a Stirling cooler. The Stirling cooler may be selectively connectable to the heat-conducting member. A cushioning member may be disposed between the heat-conducting member and the enclosure, such that vibrations from the Stirling cooler to the enclosure are reduced.

Abstract: An apparatus has a heat engine and a power output member drivenly connected to the piston of the heat engine and having an output for supplying work. The displacer is driven by an adjustable drive member. An adjustable signal generator is provided for modulating a signal which is sent to the adjustable drive to adjust the cycle profile of the displacer. The phase angle, the dwell time of the displacer at one or both ends of its cycle and/or the velocity of the displacer is thus adjusted.

Abstract: An apparatus has a heat engine and a power output member drivenly connected to the piston of the heat engine and having an output for supplying work. A feedback member responsive to power demand from the apparatus by a load is provided to modulate the amount of heat provided by the heat source to the working fluid.

Abstract: A GM type displacer has an elastomer “O” ring at the warm end to absorb impact energy when the displacer reaches the bottom of the stroke before it would hit the cylinder end cap. When the displacer reaches the top of its stroke, before the displacer would hit the internal mechanism of the expander, another elastomer “O” ring absorbs the kinetic energy of the displacer. Both absorbers are at or near ambient temperature.

Abstract: A high efficiency fuzzy logic based Stirling cycle cryogenic cooler has increased efficiency by driving the system in the demand mode (near the desired set point cooling temperature) by a more efficient sinusoidal waveform. The compressor pistons of the Stirling compressor are driven by a voice coil actuator between compressing the coolant gas and then releasing and being driven against an opposing return spring. Since a square wave provides faster cool-down, this is utilized during that mode. In addition, to utilize the rebound effect of both the ambient gas pressure and the return springs, the voice coil actuator drive is turned off during one-quarter cycle rebound portions of the cooling cycle.

Abstract: An apparatus for providing cooling has a heat engine in which the cycle profile of at least one of the displacer and the piston is variable for to provide efficient cooling at various temperature differences.

Abstract: A compact, modular, cryocooler is provided for use in relatively small-scale applications, i.e., applications requiring less than approximately 10 Watts of cooling capacity at about 10 degrees K or less. The cryocooler 10 utilizes a recuperative heat exchanger integrally combined with a floating piston expander having a piston adapted for periodic movement within an expansion cylinder. The piston is actuatable without an external drive mechanism, but rather by selective operation of processor controlled “smart”, variable current pulse valves which serve to alternately couple working fluid and ballast fluid to opposite ends of the cylinder. The valves are actuated in response to output signals generated by a non-invasive inductive sensor, which detects the position of the piston within the cylinder.

Abstract: In a free piston machine, a coil is mounted to its housing and magnetically linked to a permanent magnet or electromagnet on its piston member to form a linear motor. The coil and magnet are either added to embody the invention or are part of an AC linear alternator or AC linear motor which are a part of the free piston machine. A source of DC electrical current and a switch for connecting the DC source to the coil supply DC current to the coil when the switch is closed so that the coil and magnet temporarily operate as a DC linear motor until the piston is adequately centered for start-up without collision. The DC source voltage is temporarily applied to the coil to move the piston away from an end wall of the cylinder. This is accomplished by applying the DC current to the coil for a predetermined time interval, or by sensing when the piston has reached an adequately centered position.

Abstract: A higher temperature end of a pulse tube is connected to a lower side of a supporting member so as to position at a lower temperature end of the pulse tube at a lower position. Such a structure prevents free convection of a working gas in the pulse tube, which is a cause of reduced refrigerating efficiency. If a cold head is desired to be contacted with a member to be cooled down from its (lower) side, such a need can be satisfied by mounting the cold head on the lower temperature end of the pulse tube (a lower temperature end of a regenerator).

Abstract: A hybrid two stage expander having a first stage Stirling expander coupled to a second stage pulse tube expander. Both stages are pneumatically driven by a common reciprocating compressor in a typical application. The first stage Stirling expander provides high thermodynamic efficiency which removes a majority of the heat load from gas within the cryocooler. The second stage pulse tube expander provides additional refrigeration capacity and improved power efficiency with little additional manufacturing complexity since it has no moving parts.

Abstract: A cryocooler having an improved linear motor assembly. The cryocooler comprises a displacer unit, heat exchanger unit and compressor and linear motor assembly. The compressor and linear motor assembly includes a linear motor having both a stationary internal return iron element and a moving internal return iron element, thus enabling the motor to operate at a predetermined resonant frequency. In a preferred form, the compressor and linear motor assembly comprise a unitary structure.

Abstract: A container for high pressure gases and fluids is provided with a tubular housing having a lid fastened to one or more axially extending elements within the housing for transferring axial forces from one end of the container to the other without subjecting the housing itself to axial forces.