Abstract: An inertance tube and a surge volume for a pulse tube refrigerator system may be integrally coupled together, such as by the inertance tube being at least in part a channel in a wall of the surge volume. The surge volume may have a helical channel in an outer wall that forms part of the inertance tube. The surge volume tank may be surrounded by a cover that closes off the channel to form the inertance tube as an integral part of the surge volume. The inertance tube may have a non-circular cross section shape, such as a square shape or non-square rectangular shape. The channel may be tapered, perhaps changing aspect ratio. Alternatively, the inertance tube may be a separate tube having a non-circular shape, which may be wrapped around at least part of the surge volume.

Abstract: An inertance tube and a surge volume for a pulse tube refrigerator system may be integrally coupled together, such as by the inertance tube being at least in part a channel in a wall of the surge volume. The surge volume may have a helical channel in an outer wall that forms part of the inertance tube. The surge volume tank may be surrounded by a cover that closes off the channel to form the inertance tube as an integral part of the surge volume. The inertance tube may have a non-circular cross section shape, such as a square shape or non-square rectangular shape. The channel may be tapered, perhaps changing aspect ratio. Alternatively, the inertance tube may be a separate tube having a non-circular shape, which may be wrapped around at least part of the surge volume.

Abstract: A regenerative refrigeration system includes one or more control devices that utilize micro electro mechanical systems (MEMS) technology. Such MEMS devices may be small in size, on a scale such that it can be introduced into a refrigeration system, such as a cryocooler, without appreciably affecting the size or mass of the refrigeration system. Through the use of MEMS devices, dynamic control of the system may be achieved without need for disassembly of the system or making the system bulky. Suitable regenerative refrigeration systems for use with the MEMS devices include pulse tube coolers, Stirling coolers, and Gifford-McMahon coolers.

Abstract: A cryogenic refrigeration system includes an expansion nozzle having a high-pressure nozzle inlet and a low-pressure nozzle outlet, and a compressor having a compression device, such as a pair of opposing pistons, operable to compress gas within a compression volume. The compression volume has an inlet port and an outlet port. A flapper inlet valve has an inlet valve inlet, and an inlet valve outlet in gaseous communication with the inlet port of the compression volume. The inlet valve opens when a gaseous pressure at the inlet valve inlet is sufficiently greater than a gaseous pressure in the compression volume to overcome a spring force of the flapper inlet valve. A flapper outlet valve has an outlet valve inlet in gaseous communication with the outlet port of the compression volume, and an outlet valve outlet in gaseous communication with the nozzle inlet.

Abstract: A cryogenic refrigeration system includes an expansion nozzle having a high-pressure nozzle inlet and a low-pressure nozzle outlet, and a compressor having a compression device, such as a pair of opposing pistons, operable to compress gas within a compression volume. The compression volume has an inlet port and an outlet port. A flapper inlet valve has an inlet valve inlet, and an inlet valve outlet in gaseous communication with the inlet port of the compression volume. The inlet valve opens when a gaseous pressure at the inlet valve inlet is sufficiently greater than a gaseous pressure in the compression volume to overcome a spring force of the flapper inlet valve. A flapper outlet valve has an outlet valve inlet in gaseous communication with the outlet port of the compression volume, and an outlet valve outlet in gaseous communication with the nozzle inlet.

Abstract: A driven armature cylinder and piston link with reduced side loads and cross-bearing loads which uses a pin inserted through a dual coaxial tapered through bore in the drive piston to secure a drive piston to a displacer or compressor module cylinder, as applicable to Stirling cycle cryocoolers. Another embodiment is a method of coupling a piston to an armature cylinder with a linkage pin inserted through a dual coaxial tapered through bore to assure that the impact forces between the linkage pin and the drive piston occur at the centerline of the drive piston for centered loading and reduction of side and cross-bearing loads.

Abstract: A linear compressor (60) includes a reciprocating piston (20) for varying the volume of a compression chamber (12). A moving coil motor (26) causes the piston (20) to reciprocate against the force of an integrally machined double-helix spring (62) about a position in which the spring (62) is in a free state. The spring (62) includes a retainer (72) which is attached to the piston (20), a fixed flange (66) and two resilient helical members (78,80) which extend between the flange (66) and retainer (72) along a longitudinal axis (82). The helical members (78,80) are configured such that lateral reaction forces thereof are mutually canceling. The helical members (78,80) have the same twist direction, are interspersed with each other along the longitudinal axis (82) and are rotationally displaced from each other about the longitudinal axis (82) by substantially 180.degree..

Abstract: A split Stirling cycle type of cryogenic cooler (10) includes a compressor portion (12) and an expander portion (14). The expander portion (14) is of the "cold finger" type, and is configured to operate in near-resonance with the characteristic cyclic operating rate of the compressor portion (12). As a result, an improved performance of the cooler results both during cool down from ambient temperatures and after cool down. Additionally, a quiet operation of the cooler is provided both during and after cool down to cryogenic temperatures.

Abstract: An improved cryogenic cooler 100 includes a flange 106 with an elongated pressure vessel 120 extending therefrom. The pressure vessel 120 is connected to the flange 106 at a proximal end thereof. The pressure vessel 120 is adapted to cool a surface in the proximity of the distal end thereof. Vibration isolation is provided at both proximal and distal ends of the elongated pressure vessel. A coupler 126 serves to maintain a gap between the distal end of the pressure vessel 120 and the surface at cryogenic temperatures. In a specific embodiment, the coupler 234 has a coefficient of thermal expansion which is less than the coefficient of thermal expansion of an end cap 224 on the pressure vessel. The coefficients of expansion are chosen to provide a tight slip fit between the cooler and the coupler at ambient temperatures and a very small continuous air gap at cryogenic temperatures. Another novel feature is the provision of an energy-absorbing ring 114 within the flange to dissipate vibration therein.

Abstract: In a cryogenic refrigeration utilizing a linear drive motor, a temperature control system controls the displacement of an armature reciprocating at a fixed frequency to adjust the operating temperature of a working fluid at the cold end of a cold finger. Linear drive motors using dynamic absorbers to reduce vibration operate within the narrow frequency range to which the absorber is tuned. Controlling the maximum displacement of the armature used to compress the working fluid results in the ability to adjust the temperature at the cold end of the refrigeration without altering the frequency of operation.

Abstract: A linear motor compressor within a cryogenic refrigerator wherein the compressor space, within which a gaseous fluid is alternately compressed and expanded, is formed by a stationary piston and a reciprocating armature that is concentric about the piston. The armature is supported along a clearance seal the stationary piston. An axial bore along the stationary piston conveys gaseous fluid from the compression space to a displacer within the cold finger of the cryogenic refrigerator. An isolator for reducing transimission into and out of the compressor comprising a dynamic absorber and flat springs mounted with a damping material between the compressor and a mounting frame. A sensor for detecting the position of the armature utilizes a target magnet whose magnetic flux lines are decoupled from the flux lines generated about the coil.

Abstract: The invention discloses a cryopump comprising a primary cryopanel 67 associated with a low temperature heat sink 60 having means for adsorbing a first low boiling point gas and a secondary cryopanel 80 associated with heat sink 60 and a higher temperature heat sink 48 having means for condensing a higher boiling point gas. There are means 90 for selectively irradiating the primary cryopanel from a location external to the vacuum chamber. The radiation raises the temperature of the cryopanel above that which is necessary to cause said first gas to become desorbed from said cryopanel while having minimal effect on the capacity of the higher temperature heat sink.

Abstract: The present invention relates to a cryopump having a gas bearing formed in a clearance seal between a piston and a cylinder. The gas bearing is formed by forcing pressurized gas from a gas plenum through orifices to the clearance seal.

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

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

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