The application relates to a cryogenic machine of the regenerative type, comprising: a pressure oscillator, at least one cold finger (20) in fluid connection with the pressure oscillator,

wherein the pressure oscillator comprises a centrifugal compressor (1) and a fluid distribution member (12) configured to alternately distribute high-pressure and low-pressure working fluid from the centrifugal compressor into said cold finger.

An inertance tube for a pulse tube refrigerator which can be tuned to optimize performance. Apertures in the inertance tube fluidly communicate the inertance tube with a fluid reservoir. The effective length of the inertance tube is changed by alternatively closing or opening the apertures. Changing the effective length of the inertance tube causes a phase shift between the mass flow and pressure waves in the working gas which, in turn, changes the acoustic power. Controlling the phase angle improves Carnot efficiency. The cooling load capacity of the pulse tube refrigerator is a function of the acoustic power.

A pulse-tube cryocooler includes a compressor piston that is axially aligned with a pulse tube. The compressor piston is an annular piston that has a central hole around its axis. An inertance tube, connected to one end of the pulse tube, runs through the central hole in the compressor piston. The cryocooler also includes a balancer that moves in opposition to the compressor piston, to offset the forces in moving the compressor piston. The balancer may also be axially aligned with the pulse tube, the annular piston, and the inertance tube. The alignment of the compressor piston, the pulse tube, and the inertance tube aligns the forces produced by movement of fluid within the cryocooler.

In a cryogenic regenerator including a regenerator tube, a partitioning tube, whose tube wall is perforated by uniformly distributed through-holes, inside of which regenerator packing is provided, and having rib rings wrapped peripherally around its outer wall, is arranged coaxially inside the regenerator tube, with a buffer cavity between the regenerator-tube inner wall and the partitioning-tube outer wall. In a pulse-tube refrigerator including the regenerator and a gas reservoir, the regenerator, thanks to the designing of its reservoir and through-holes, draws in radial flows such that the form of heat exchange in the same regenerator cross-section goes from being simple thermal conduction to being heat exchange in which heat convection is coupled with thermal conduction, enhancing radial heat transfer and enabling rapid equilibration of temperature gradients along the regenerator periphery, and, by effectively keeping non-uniformity phenomena inside the regenerator under control, making improved refrigerator efficiency possible.

A pulse-tube cryocooler includes a compressor piston that is axially aligned with a pulse tube. The compressor piston is an annular piston that has a central hole around its axis. An inertance tube, connected to one end of the pulse tube, runs through the central hole in the compressor piston. The cryocooler also includes a balancer that moves in opposition to the compressor piston, to offset the forces in moving the compressor piston. The balancer may also be axially aligned with the pulse tube, the annular piston, and the inertance tube. The alignment of the compressor piston, the pulse tube, and the inertance tube aligns the forces produced by movement of fluid within the cryocooler. This makes it easier to cancel mechanical forces produced by the cryocooler in operation, since all (or most) of the forces are in a single axial direction.

A cooling device comprises a cooling tube containing a working gas, a pressure oscillator connected to a first end of the cooling tube to generate a pressure oscillation and displacement of the working gas, and means for phase shifting the pressure oscillation relative to displacement of the working gas, connected to a second end of the cooling tube. The device further comprises a first sealed pressure transmission element to separate the working gas from a fluid contained in the phase shifting means. The fluid and the working gas are of different natures.

Various embodiments are directed to a pulse tube cooler. The pulse tube cooler may comprise a fluid compressor, a first regenerator, a first pulse tube, a first reservoir, a second regenerator, a second pulse tube, and a second reservoir. The first end of the first regenerator may be in fluid communication with the fluid compressor. The cold end of the first pulse tube may be in fluid communication with the second end of the first regenerator. The first reservoir may be in fluid communication with the hot end of the first pulse tube. The first end of the second regenerator may be in fluid communication with the cold end of the first regenerator. The cold end of the second pulse tube may be in fluid communication with the second end of the second regenerator. The cold end of the first pulse tube and the hot end of the second pulse tube may be in fluid communication with one another through the second reservoir.

An inertance tube for a pulse tube cryogenic cooler which can be tuned to optimize performance. Apertures in the inertance tube fluidly communicate the inertance tube with a fluid reservoir. The effective length of the inertance tube is changed by alternatively closing or opening the apertures. Changing the effective length of the inertance tube causes a phase shift between the mass flow of and pressure waves in the enclosed working fluid which, in turn, changes the acoustic power. The cooling load capacity of the pulse tube cryogenic cooler is a function of the acoustic power. Controlling the phase angle improves the cooler's Carnot efficiency.

A pulse tube refrigerator/cryocooler apparatus including: an inlet for receiving a cyclically moving volume of gas; a regenerator device fluidly connected to the inlet for storing and recovering thermal energy from the gas; a pulse tube fluidly connected to the regenerator; and a conduit fluidly connected at one end to the pulse tube and fluidly connected at its opposite end to a container, said container providing a storage volume for gas, wherein apparatus is configured such that the cyclically moving gas enters the regenerator in a direction parallel to its elongate axis.

A system includes a pulse tube, a compressor configured to create pulses of fluid in the pulse tube, and a surge tank. The surge tank includes a housing that defines a surge volume configured to receive the fluid from the pulse tube. An inertance channel defines a passageway through which the fluid flows to and from the surge volume. At least part of the inertance channel has an open side to the surge volume. The surge tank also includes an adjustable seal configured to block at least part of the open side of the inertance channel and to move in order to change a functional length of the inertance channel. The housing may include a material having a high coefficient of thermal expansion, and the adjustable seal may include a material having a low coefficient of thermal expansion.