Abstract: A bearing support system for a piston and its connecting rod in which the bearing system supports the combined piston and connecting rod by only two bearings, a gas bearing at the piston and a radially acting spring bearing at its connecting rod. A non-compliant connecting rod is fixed to an end of a piston which has a clearance seal length in the range of 0.3 times the diameter of the piston and 1.5 times the diameter of the piston. The distance from the gas bearing to the effective point of connection of the radially acting spring bearing to the connecting rod is greater than the seal length of the piston. The piston and connecting rod unit is not supported by additional bearings that introduce additional alignment problems.

Abstract: An automated, ultra-low temperature freezer having multiple structural features that reduce heat transfer into the freezer, protect its internal mechanical devices against low temperature mechanical binding of their movements, allow defrosting and autoclaving as a result of only minimal changes to the conventional CO2 emergency backup system. A group of freezers are arranged so they can simultaneously provide an HVAC function. A vial management system allows biological samples or vials to be automatically placed in and recovered from the freezer and associates the temperature history with each sample or vial that it was subjected to during its storage.

Abstract: An opposed piston gamma type Stirling machine has its displacer driven by a linear electromagnetic transducer that is drivingly linked to the displacer and is located on the opposite side of the power piston's axis of reciprocation from the displacer preferably in the bounce space. The linear transducer is controlled by an electronic control as a function of sensed inputs of Stirling machine operating parameters. In addition to allowing improvements in stability and efficiency, such a Stirling machine operated as a cooler/heat pump can also be controlled so that its displacer can be driven at (1) a phase angle that pumps heat in one direction through the machine or (2) at another phase angle that pumps heat in the opposite direction through the machine and allows selectively switching between the heat pumping directions.

Abstract: A beta-type free-piston Stirling cycle engine or cooler is drivingly coupled to a linear alternator or linear motor and has an improved balancing system to minimize vibration without the need for a separate vibration balancing unit. The stator of the linear motor or alternator is mounted to the interior of the casing through an interposed spring to provide an oscillating system permitting the stator to reciprocate and flex the spring during operation of the Stirling machine and coupled transducer. The natural frequency of oscillation, ?s, of the stator is maintained essentially equal to ? p ? 1 - ? p k p and the natural frequency of oscillation of the piston, ?p, is maintained essentially equal to the operating frequency, ?o of the coupled Stirling machine and alternator or motor.

Abstract: A free-piston Stirling machine drivingly coupled to at least one rotary electromagnetic transducer. At least one pulley is oriented in a plane of a reciprocating piston connecting rod. At least one motion translating drive link connects the connecting rod to the pulley by at least two straps so that the pulley moves in rotationally oscillating motion. The two straps extend along an arcuate surface of the pulley into connection to the piston rod at two spaced locations. The pulley is linked to a rotary electromagnetic transducer so that both move in rotationally oscillating motion. Preferably a piston spring resonates the piston at an operating frequency of the Stirling machine and a torsion spring resonates the pulley in rotational oscillation at the operating frequency of the Stirling machine.

Abstract: A bearing support system for a piston and its connecting rod in which the bearing system supports the combined piston and connecting rod by only two bearings, a gas bearing at the power piston (or displacer) and a radially acting spring bearing at its connecting rod. The spacing between them meets prescribed relationships and preferably exceeds a calculated value based upon chosen engineering parameters. A non-compliant connecting rod is fixed to an end of a piston which has a clearance seal length in the range of 0.3 times the diameter of the piston and 1.5 times the diameter of the piston. The distance from the gas bearing to the effective point of connection of the radially acting spring bearing to the connecting rod is greater than the seal length of the piston.

Abstract: An improved free piston Stirling machine having a gamma configuration. The displacer and each piston is reciprocatable within a cylinder having an unobstructed opening at its inner end into a common volume of the workspace. The common volume is defined by the intersection of inward projections of the displacer cylinder and the piston cylinders. The displacer and the pistons each have a range of reciprocation that extends into the common volume. A displacer drive rod is reciprocatable in a drive rod cylinder and both are positioned outside the common volume and on the opposite side of the common volume from the displacer. The displacer is connected to the displacer drive rod by a displacer connecting rod. Importantly, the displacer and pistons have complementary interfacing surface contours formed on their inner ends which substantially reduces the dead volume of this gamma configured machine.

Abstract: A regenerator having a plurality of involute foils disposed in an annular gap between an inner cylindrical tube and an outer cylindrical tube. The involute shape of the foils provides uniform spacing throughout the entire regenerator and substantial surface area for fluid contact.

Abstract: A regenerator having a plurality of involute foils disposed in an annular gap between an inner cylindrical tube and an outer cylindrical tube. The involute shape of the foils provides uniform spacing throughout the entire regenerator and substantial surface area for fluid contact.

Abstract: To provide a less expensive and high-efficient free-piston Stirling cycle machine with an outer diameter of entire machine being relatively small. In a Stirling cycle cooler as a free-piston Stirling cycle machine including a cylinder 7, a piston 18 which is reciprocable inside said cylinder 7 and an electromagnetic driving mechanism 19 for reciprocating said piston 18, said electromagnetic driving mechanism 19 is comprised of a mover 20 and a stator 35, said piston 18 and said mover 20 formed by disposing a permanent magnets 24 outside an inner yoke 23 made of magnetic flux conducting material are disposed in an axial alignment, and said stator 35 and said cylinder 7 are disposed in an axial alignment.

Abstract: To provide a less expensive and high-efficient free-piston Stirling cycle machine with an outer diameter of entire machine being relatively small. In a Stirling cycle cooler as a free-piston Stirling cycle machine including a cylinder 7, a piston 18 which is reciprocable inside said cylinder 7 and an electromagnetic driving mechanism 19 for reciprocating said piston 18, said electromagnetic driving mechanism 19 is comprised of a mover 20 and a stator 35, said piston 18 and said mover 20 formed by disposing a permanent magnets 24 outside an inner yoke 23 made of magnetic flux conducting material are disposed in an axial alignment, and said stator 35 and said cylinder 7 are disposed in an axial alignment.

Abstract: A beta-type free-piston Stirling cycle engine or cooler is drivingly coupled to a linear alternator or linear motor and has an improved balancing system to minimize vibration without the need for a separate vibration balancing unit. The stator of the linear motor or alternator is mounted to the interior of the casing through an interposed spring to provide an oscillating system permitting the stator to reciprocate and flex the spring during operation of the Stirling machine and coupled transducer. The natural frequency of oscillation, ?s, of the stator is maintained essentially equal to ?p ? p ? 1 - ? p k p and the natural frequency of oscillation of the piston, ?p, is maintained essentially equal to the operating frequency, ?o of the coupled Stirling machine and alternator or motor.

Abstract: An improved, free-piston, Stirling machine having at least three pistons series connected in an alpha Stirling configuration. Each cylinder is stepped so that it has a relatively larger diameter interior wall and a coaxial, relatively smaller diameter interior wall. Each piston is also stepped so that it has a first component piston having an end face facing in one axial direction and matingly reciprocatable in the smaller diameter cylinder wall and a second component piston having an end face facing in the same axial direction and matingly reciprocatable in the larger diameter, cylinder wall. One of the piston end faces bounds the compression space and the other end face bounds the expansion space. Preferably, each stepped piston has peripheral, cylinder walls that are axially adjacent and joined at a shoulder forming the end face of the larger diameter component piston.

Abstract: An apparatus for determining position of a free piston used in such as hydraulic compressor, which has no mechanical connection with crank shaft, and an apparatus for controlling reciprocating motion of the free piston are disclosed. A free piston position determining apparatus comprises a magnetic sensor disposed in a case containing a free piston, and a magnet disposed on the free piston. The magnet sensor generates pulse train when the magnet is positioned within a pre-determined distance form the magnet sensor. Stroke of the free piston is computed based on duration of the pulse, and offset of the average piston position from designed average position is computed based on interval of the pulse.

Abstract: The invention provides a compact and inexpensive cooling device with high heat transfer efficiency and with easy maintenance. The cooling device includes a condenser (10), an evaporator (20), and a pair of refrigerant flow passages between them. In each of the condenser (10) and the evaporator (20), through holes (11a, 21a) are formed in parallel with each other. The condenser (10) is formed in a cylindrical shape and installed around the cooling head of the refrigerator by a clamp (14). The evaporator (20) is installed the outside. The refrigerant is liquefied in the condenser (10) by releasing its heat, flows down into the evaporator (20) through the flow passage and is vaporized in the evaporator (20) by absorbing heat from the outside. The vaporized refrigerator flows up and returns into the condenser (10).

Abstract: A regenerator having a plurality of involute foils disposed in an annular gap between an inner cylindrical tube and an outer cylindrical tube. The involute shape of the foils provides uniform spacing throughout the entire regenerator and substantial surface area for fluid contact.

Abstract: A regenerator having a plurality of involute foils disposed in an annular gap between an inner cylindrical tube and an outer cylindrical tube. The involute shape of the foils provides uniform spacing throughout the entire regenerator and substantial surface area for fluid contact.

Abstract: The invention provides a compact and inexpensive cooling device with high heat transfer efficiency and with easy maintenance. The cooling device includes a condenser (10), an evaporator (20), and a pair of refrigerant flow passages between them. In each of the condenser (10) and the evaporator (20), through holes (11a, 21a) are formed in parallel with each other. The condenser (10) is formed in a cylindrical shape and installed around the cooling head of the refrigerator by a clamp (14). The evaporator (20) is installed the outside. The refrigerant is liquefied in the condenser (10) by releasing its heat, flows down into the evaporator (20) through the flow passage and is vaporized in the evaporator (20) by absorbing heat from the outside. The vaporized refrigerator flows up and returns into the condenser (10).

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: An enclosure for a refrigerated space. The enclosure may include a thermosiphon and a Stirling cooler. The thermosiphon may include a condenser end and an evaporator end. The ends may be connected by a small diameter pipe and a large diameter pipe. The Stirling cooler may drive the thermosiphon to cool the refrigerated space.