Abstract: An apparatus for detecting and reducing excessive amplitude of oscillation of a free piston slidably mounted in a housing. The housing has a vibration absorber, including a mass mounted through a spring to the housing. The mass reciprocates relative to the housing along a path in a phase relationship to the piston. A sensor is mounted near the mass for detecting the amplitude of oscillation of the mass. A controller is connected to the sensor for reducing the amplitude of oscillation of the piston when the amplitude of oscillation of the mass reaches a predetermined maximum.

Abstract: A thermoacoustic engine-generator that converts waste heat into electrical power. Thermal energy is converted to useful work via temperature-pressure amplification of periodic acoustic traveling waves in a compressible working fluid which cause the armature of a linear alternator to reciprocate and produce alternating current electrical energy. An external oscillator initiates reciprocating motion in the armature of a linear alternator. The armature is a combination fluid pump and fluid motor as well as the induction armature of a linear alternator. The pump end of the armature generates an acoustic traveling wave with each cycle of the armature. The traveling wave enters a waveguide-heat exchanger and is amplified in temperature, pressure and propagation velocity by thermal conduction of energy through the wall of the waveguide.

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: The invention can prevent gas leakage and reduce friction force while relaxing tolerance for manufacturing a displacer and the like for Stirling cycle machines. Gas leakage between the outer periphery of a seal (1) and the inner peripheral surface (5a) of a cylinder (5) is prevented. Accordingly, precise finish of the radial clearance between the displacer (2) and the cylinder (5) is not required. As the difference of pressures between the front and rear spaces of the displacer (2) is small, the gas leakage is sufficiently prevented without pressing the seal (1) against the inner peripheral surface (5a) of the cylinder (5). On the other hand, as the friction force generated between them is significantly small, it does not affect the reciprocation of the displacer. As the seal (1) is provided so as not to be restricted axially and radially, the displacer is kept closely contacted with the inner peripheral surface (5a) of the cylinder (5) even if the displacer (2) eccentrically shifts.

Abstract: A gas restrictor particularly usrful for applicatio in gas bearing as used, for example, in free-piston Striling cycle machinery. Porous strip material together with a backing plate and orifice (bleed hole) is used to provide the restriction to the flow of gas into an annular gap between a piston and a cylinder.

Abstract: A piston position drift control for a free-piston device. The control includes a passage connecting internal volumes of the device, the passage being substantially shorter than an acoustic wavelength of the device; and a check valve in the passage for controlling fluid communication between the internal volumes, the check valve having an opening pressure not less than approximately 20% of a maximum pressure differential of the device at a maximum stroke. The control is passive, requires no active control once in service, provides low susceptibility to damage or fouling, and is amenable to adjustment or repair if needed. In addition, the control is small and inexpensive, and functions across the entire operational range of a free-piston device it supports. A related free-piston device including the piston position drift control is also provided.

Abstract: A spring standoff for a reciprocating device, the standoff having a generally cylindrical body and having a window in a circumferential surface of the body, and a flange at each end of the body, one flange to be coupled to a planar spring of the reciprocating device, and the other flange to be coupled to a sealing container of the reciprocating device. The body generally concentrically houses at least a portion of a reciprocating rod coupled to the planar spring of the reciprocating device.

Abstract: A piston assembly for use in a motor comprises a cylinder having a bore, an electrically conductive piston reciprocally disposed within the cylinder bore, a gas cavity formed within the piston, and one or more gas bearings associated with the piston, each of the one or more gas bearings including an aperture formed within the piston and an electrically conductive tubular member extending through the aperture, the tubular member having a lumen in communication between the gas cavity and the cylinder bore. The piston assembly may be used in connection with a motor used in a cryocooler that is driven by oscillating magnetic energy fields.

Abstract: Stirling engine which may be used as a heat pump, which consists of a hot half and a cold half. Both halves are connected by two lines which constitute a counterflow heat exahnger or in which a counterflow heat exchanger is mounted. Moreover, a mutual shaft, to which in the hot half a large and a small piston are mounted and to which in the cold half a large and a small piston are mounted, connects both parts. For every up or down going movement of the shaft, a complete Stirling cycle is performed. If desired, the shaft may be replaced by a hydraulic interconnection.

Abstract: A free-piston type Stirling engine used for producing cold heat with the vibration center position of a piston accurately kept. A first space is formed on one side of a piston, and a second space is formed on the opposite side to spread up to a portion adjacent to a cylinder's side wall. A piston is provided with a vibration-direction first groove extending up to the first space and a circumferential-direction second groove, and a cylinder is provided with a hole penetrating the side wall thereof. The second groove of the piston, when coupled with the cylinder's hole during a piston vibration process, allows the first space to communicate with the second space. Accordingly, a short-time communication between the first and second spaces will balance pressures in the two spaces against each other to keep the vibration center position of the piston accurately.

Abstract: The performance of a multi-stage inertance pulse tube cryocooler in accordance with an embodiment of the present invention may be enhanced by cooling the inertance tube of one stage placing it in thermal communication with the cool heat exchanger of a preceding stage. Cooling at least one inertance tube of a multi-stage cooler in this invention lowers the viscosity and sound speed of the gas in the inertance tube, thereby improving the cooling power for that subsequent cooling stage, and for the entire device.

Abstract: A Stirling engine comprising: a displacer unit having displacer cylinders, displacers slidably arranged in the chambers of the displacer cylinders, expansion chambers and contraction chambers into which, and from which, the operation gas flows with the operation of the displacers; and a power piston unit having a power cylinder having an operation chamber communicated with either the expansion chamber or the contraction chamber of the displacer unit, and a power piston slidably arranged in the power cylinder; wherein the displacer cylinders of the displacer unit are equipped with a heating wall surrounding a heat source and cooling walls forming a plurality of cylinder chambers surrounding the heating wall; and the displacers of the displacer unit are slidably arranged in the plurality of cylinder chambers in the directions to approach the heat source and to separate away from the heat source.

Abstract: The Stirling cycle engine includes: a casing having a cylindrical shape; a cylinder for sidably inserting a displacer and a piston into a part adjacent to one end and another part adjacent to an other end thereof respectively,_the cylinder being coaxially placed inside the casing; a driving mechanism provided around an outer peripheral surface of the cylinder so as to force the piston to reciprocate inside the cylinder; a mount for fixing the driving mechanism to the outer peripheral surface of the cylinder, the mount being integrally formed with the cylinder; a flat spring having a center portion thereof connected to the piston; and a plurality of connecting arms, one ends thereof being integrally formed with the mount and the other ends thereof being connected to a peripheral portion of the flat spring.

Abstract: A Stirling engine comprising a casing, a displacer arranged in the casing so as to slide, an expansion chamber and an operation chamber into which, and from which, an operation gas flows with the operation of the displacer, and a power piston that is operated in response to a change in the pressure of the operation gas in the operation chamber, wherein the Stirling engine further comprises a displacer operation means having a moving yoke disposed in the displacer and a pair of electromagnetic solenoids disposed to surround the moving yoke and juxtaposed to each other in the axial direction in the casing; a power piston position detection means for detecting the operation position of the power piston; and a control means for controlling to switch over the excitation of the pair of electromagnetic solenoids of the displacer operation means based on a detection signal from the power piston position detection means.

Abstract: In a reciprocating device having a moving element, a stator and a flexing suspension for coupling the moving element and stator and for maintaining the moving element on axis, the flexing suspension comprising: at least one flexing element locating the stator relative to the moving element by directly engaging features of the flexing element to mating features of the stator.

Abstract: A thermoelectric generating device has a thermoelectric element which utilizes an exhaust gas from an engine as a high temperature heat source and an engine coolant as a low temperature heat source in order to generate electricity. An introducing passage introduces a part of the exhaust gas passed through the thermoelectric element into an intake of the engine. An introducing valve opens and closes the introducing passage. A controller controls an opening degree of the introducing valve according to a load of the engine.

Abstract: A thermoacoustic refrigerator having a relatively small size which utilizes one or more piezoelectric drivers to generate high frequency sound within a resonator at a frequency of between about 4000 Hz and ultrasonic frequencies. The interaction of the high frequency sound with one or more stacks create a temperature gradient across the stack which is conducted through a pair of heat exchangers located on opposite sides of each stack. The stack is comprised of an open-celled material that allows axial, radial, and azimuthal resonance modes of the resonator within the stack resulting in enhanced cooling power of the thermoacoustic refrigerator.

Abstract: A Stirling engine comprising:

Abstract: The invention is for a continuous-combustion, closed-cycle, gas turbine engine with a regenerator and a displacer. It has embodiments that remove heater and cooler interior volumes during gas compression, which enable it to scale well to very large sizes. Low combustion temperatures insure very low emissions. The displacer levitated by an integral gas bearing and small clearance seal and given oscillatory translational motion by electromagnetic forces operates without surface wear. The turbine blades, subjected only to warm gases, are durable and inexpensive. Thus, this engine has a very long, continuous, maintenance-free service life. This gas turbine engine also operates without back work allowing high efficiency for both low and rated output. Pressurized encapsulation permits use of low-cost ceramics for high temperature components. The invention includes a unique monolithic ceramic heater, a compact high-capacity regenerator and a constant-power gas turbine.

Abstract: A piston assembly for use in a motor comprises a cylinder having a bore, an electrically conductive piston reciprocally disposed within the cylinder bore, a gas cavity formed within the piston, and one or more gas bearings associated with the piston, each of the one or more gas bearings including an aperture formed within the piston and an electrically conductive tubular member extending through the aperture, the tubular member having a lumen in communication between the gas cavity and the cylinder bore. The piston assembly may be used in connection with a motor used in a cryocooler that is driven by oscillating magnetic energy fields.

Abstract: Thermoacoustic devices are disclosed wherein, for some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output. In an example embodiment, the combustion zone and the regenerator are thermally insulated from other components within the thermoacoustic device.

Abstract: In a Stirling cycle engine, a regenerator has a bobbin, a resin film wound around the outer surface of the bobbin, and a sheath fitted around the outer surface of the resin film and having a slit formed vertically therein. The resin film has one end fixed on the outer surface of the bobbin, and has the other end led out through the slit and fixed to an end surface of the slit or to the outer surface of the sheath. The sheath is press-fitted on the inner surface of the cylinderenclosure. Working gas flows between different layers of the resin film. This reduces the loss of heat due to gas leakage and thereby improves the heat exchange efficiency in the regenerator.

Abstract: Thermoacoustic devices are disclosed wherein, for some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output. In an example embodiment, the combustion zone and the regenerator are thermally insulated from other components within the thermoacoustic device.

Abstract: A thermocoustic device includes a housing with a thermal core supported in the housing and having a first and a second surface. The thermal core includes a first heat exchanger defining the first surface of the thermal core and a second heat exchanger defining the second surface of the thermal core. A main chamber is in fluid communication with the first surface of the thermal core and a secondary multiplier chamber is in fluid communication with the second surface of the thermal core. A working volume of a gaseous working fluid fills the main chamber, the multiplier chamber, and the thermal core at a pressure. An equilibrium pressure is defined as the pressure of the working volume of gaseous working fluids with the thermoacoustic device is in a non-operating mode.

Abstract: There are many heat sources on the earth, and those heat sources radiate heat continuously. Though some of such heat sources are utilized with heat exchange technologies now, they can't deliver power to us effectively. In addition, though external combustion engines can utilize the heat generated from fuel combustion, they let out much carbon dioxide at the same time. This invention has solved above problem. In this invention, the driving energy for the external combustion engine (2) comes from the heat ventilation part/absorption part of the heat pump (1); wherein said heat pump (1) is a metal oxide heat pump (11), and said external combustion engine is a Sterling Engine (21) or a thermo-metal engine (22).

Abstract: A Stirling engine includes a heat exchanger having helical and axial fins forming an orthogonal grillage on either side of a pressure resisting wall, and an outer reinforcing sleeve about the helical fins. The sleeve improves the pressure resisting ability of a thin separating wall between a pressurized fluid and an outside working environment, resulting in a high-pressure and temperature heat exchanger with high heat transfer efficiency. In addition, the sleeve and helical fins together define fluid passages for the flow of heating fluid. The heat exchanger according to the invention has the ability to resist high pressures at high temperatures without excessive distortion, has improved heat transfer capability, better reliability, and lower production cost than prior art heat exchangers.

Abstract: A thermoacoustic engine for acoustically driving a thermal exchange includes a hollow drive tube, a heat transfer medium, an acoustic resonator, and a first thermal element. The hollow drive tube partially contains the heat transfer medium and is connected to and opens into the acoustic resonator. The acoustic resonator is adapted to store acoustic energy and deliver at least one acoustic wave to the heat transfer medium. The first thermal element includes a first channel and a first working fluid. The first channel is positioned to cross and open into the hollow drive tube, at least partially contains the first working fluid, and is sized to decrease the propagation of the at least one acoustic wave within the first channel. The first thermal working fluid is adapted to interact with and undergo thermal exchange with the heat transfer medium by conduction.

Abstract: A Stirling cycle engine comprises a substantially sealed engine block that defines a working fluid space, a hot path and a cold path. A heat source and a heat sink are configured to keep the hot path and the cold path at different temperatures. The engine includes a valve chamber that is communication with the working fluid space, the hot path and the cold path. A valve is moveably positioned within the valve chamber between at least a first position and a second position. The valve defines a passage that, in the first position, places the working fluid space in communication with the hot path and, in the second position, places the working fluid space in communication with the cold path. A regenerator positioned within the passage.

Abstract: A heat pumping machine, such as used for home heating and cooling, has a free piston Stirling engine driving a vapor compression heat pump. The engine is mechanically linked to the compressor inside a common hermetically sealed enclosure. A fluid conducting passage connects the refrigerant flow path in communication with a working gas space in the Stirling engine. Although carbon dioxide may be used in both as the refrigerant and the engine working gas, preferably both helium and carbon dioxide are used and separated by a phase separator so that helium rich gas is directed into the Stirling engine and carbon dioxide rich fluid is directed through the heat pump.

Abstract: A novel thermodynamic engines including a piston operating on a compressible fluid in a thermally insulated volume, which also includes a movable displacer which selectively divides the internal volume between a warm and a cold side, and a regenerator through which the fluid from the selectively divided volume passes and transfer its heat to or receives heat from, wherein the piston and displacer are each periodically moved in various complex motions according to the present invention to provide efficiency higher than Carnot efficiency. The resulting novel structures and methods, generally referred to as “Superclassical Cycle” engines, incorporate constant volume cooling and aspects of the “Proell Effect” (relative to cooling) to achieve improved efficiencies wherein the gas temperature on the cold side of a fluid displacer is below the lowest regenerator temperature due to “self-refrigeration.

Abstract: A multiple port rotary valve for flow switching comprises a rotor (2), a stator (7), a compressor supply (8) and a compressor return (6). Gas is supplied via the compressor supply throughout a switching cycle such that the rotor is lifted away from the stator (7). The valve further comprises a balance ram to counteract the effect of the differential pressure produced by the compressor supply, such that a gas seal is formed at the rotor/stator interface.

Abstract: A magnet ring assembly for use with a piston assembly includes a cylindrical magnet holder having an inner surface, an annular ledge formed around the inner surface of the cylindrical magnet holder, and a swaged axial edge opposite the annular ledge, and a plurality of arcuate magnet sectors having a radially uniform magnetic polarity, the plurality of magnets being bonded around the inner surface of the cylindrical magnet holder, each of the plurality of magnets having opposing axial edges, one of the axial edges being disposed on the annular ledge, and the other of the axial edges being captured by the swaged axial edge of the cylindrical magnet holder. The magnet ring assembly can be used in connection with a crycooler.

Abstract: An external combustion engine includes: a plurality of cavities; a compressible working fluid in fluid communication between each pair of adjacent cavities; and a plurality of hydraulic linkages in reciprocal phase communication between each pair of alternate cavities. In an alternative embodiment the external combustion engine includes: a plurality of cavities; a compressible working fluid in fluid communication between each pair of adjacent cavities; and a plurality of articulated mechanical linkages in reciprocal phase communication between each pair of alternate cavities. In another alternative embodiment the external combustion engine includes: at least four upright cavities disposed substantially equidistant from a central upright axis; a compressible working fluid in fluid communication between each pair of adjacent cavities; and at least one linkage in reciprocal phase communication between each pair of alternate cavities. The at least one linkage may comprise a hydraulic linkage.

Abstract: An oscillating-wave engine or refrigerator having a regenerator or a stack in which oscillating flow of a working gas occurs in a direction defined by an axis of a trunk of the engine or refrigerator, incorporates an improved heat exchanger. First and second connections branch from the trunk at locations along the axis in selected proximity to one end of the regenerator or stack, where the trunk extends in two directions from the locations of the connections. A circulating heat exchanger loop is connected to the first and second connections. At least one fluidic diode within the circulating heat exchanger loop produces a superimposed steady flow component and oscillating flow component of the working gas within the circulating heat exchanger loop. A local process fluid is in thermal contact with an outside portion of the circulating heat exchanger loop.

Abstract: A thermocoustic device includes a housing with a thermal core supported in the housing and having a first and a second surface. The thermal core includes a first heat exchanger defining the first surface of the thermal core and a second heat exchanger defining the second surface of the thermal core. A main chamber is in fluid communication with the first surface of the thermal core and a secondary multiplier chamber is in fluid communication with the second surface of the thermal core. A working volume of a gaseous working fluid fills the main chamber, the multiplier chamber, and the thermal core at a pressure. An equilibrium pressure is defined as the pressure of the working volume of gaseous working fluids with the thermoacoustic device is in a non-operating mode.

Abstract: One embodiment of a spring with an integral dynamic gas seal according to the present invention includes a spring with a pair of spaced-apart ends and a spring body extending therebetween. The spring body includes a perimeter wall formed of a first material and extending in a longitudinal direction. The wall has a plurality of openings defined therein. The openings are provided in a plurality of transverse tiers. Each tier includes a plurality of separate openings each extending along a portion of the perimeter. The openings in each tier are spaced apart so as to define a post between each adjacent opening such that each tier includes a plurality of posts. The openings in each tier are staggered with respect to the openings in adjacent tiers such that each of the openings in each tier overlie one of the posts in an adjacent tier. A closure member closes each of the openings such that the spring body is sealed.

Abstract: A thermoacoustic engine for acoustically driving a thermal exchange includes a hollow drive tube, a heat transfer medium, an acoustic resonator, and a first thermal element. The hollow drive tube partially contains the heat transfer medium and is connected to and opens into the acoustic resonator. The acoustic resonator is adapted to store acoustic energy and deliver at least one acoustic wave to the heat transfer medium. The first thermal element includes a first channel and a first working fluid. The first channel is positioned to cross and open into the hollow drive tube, at least partially contains the first working fluid, and is sized to decrease the propagation of the at least one acoustic wave within the first channel. The first thermal working fluid is adapted to interact with and undergo thermal exchange with the heat transfer medium by conduction.

Abstract: Disclosed are two-stage inter-phasing pulse tube refrigerators with and without shared buffer volumes.

Abstract: The present invention provides heat exchanging elements for use in Stirling engines. According to the present invention, the heat exchanging elements are made from muliple platelets that are stacked and joined together. The use of platelets to make heat exchanging elements permits Stirling engines to run more effiecient because the heat transfer and combustion processes are improved. In one embodiment, multi-stage combustion can be introduced with platlets, along with the flexibility to use different types of fuels. In another embodiment, a single component constructed from platelets can provide the heat transfer rquirements betweeen the combustion gas/working gas, working gas in the regenerator and the working gas/coolant fluid of a Stirling engine. In another embodiment, the platelet heat exchanging element can recieve solar energy to heat the Stirling engine's working gas. Also, this invention provides a heat exchanging method that allows for multiple fluids to flow in opposing or same direction.

Abstract: A method for operating a thermoacoustic engine which produces acoustic energy which may be used to generate refrigeration wherein energy delivery fluid from a hot energy source, which provides heat to the thermoacoustic engine, is used to provide heat to a first heat sink such as a Kalina cycle and then at a lower temperature to a second heat sink.

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 thermoacoustic refrigerator having a relatively small size which utilizes one or more piezoelectric drivers to generate high frequency sound within a resonator at a frequency of between about 4000 Hz and ultrasonic frequencies. The interaction of the high frequency sound with one or more stacks create a temperature gradient across the stack which is conducted through a pair of heat exchangers located on opposite sides of each stack. The stack is comprised of an open-celled material that allows axial, radial, and azimuthal resonance modes of the resonator within the stack resulting in enhanced cooling power of the thermoacoustic refrigerator.

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: 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 centering apparatus for a free piston Stirling engine including a pressure regulator valve which connects a passageway between the work space and the back space when both (a) the average pressure in the back space exceeds the average pressure in the work space as a result of the piston deflecting a spring, and simultaneously (b) the instantaneous pressure in the back space exceeds the instantaneous pressure in the work space. A diaphragm spans across an actuator housing cavity, dividing the cavity into an upper chamber and a lower chamber. A connector valve is linked to the diaphragm for opening and closing the valve upon displacement of the diaphragm. When the average back space pressure exceeds the average work space pressure, the diaphragm is displaced to open the valve, connecting the work space and the back space in fluid communication. A check valve permits the flow of gas in only one direction: from the back space to the work space.