A GM cryocooler includes a displacer that is reciprocatable in an axial direction; a displacer cylinder that houses the displacer; a drive piston that is coupled to the displacer so as to drive the displacer in the axial direction; and a piston cylinder that houses the drive piston and that includes a drive chamber of which a pressure is controlled to drive the drive piston, and a gas spring chamber which is airtightly formed with respect to the displacer cylinder and is partitioned from the drive chamber by the drive piston.

A pneumatically driven cryogenic refrigerator operating primarily on the Gifford-McMahon (GM) cycle is switched from cooling to heating by a switch valve between a rotary valve and a drive piston that causes the displacer to reciprocate. The rotary valve has ports at two radii, one that cycles flow to the displacer and a second that cycles flow to the drive piston. Two ports cycle flow to the top of the drive piston, the “cooling” port optimizes the cooling cycle and the “heating” port provides a good heating cycle. A switch valve that changes the flow from one port to the other can be linearly or rotary actuated. The rotary valve does not reverse direction.

An air distribution mechanism and a corresponding cryogenic refrigerator are provided. The air distribution mechanism includes an air distribution valve (6) and a rotary valve (7), the air distribution valve (6) includes an air distribution valve main body (6a) and an air distribution valve seat (6b), an air distribution plane (6a3) that is on the air distribution valve main body (6a) and faces away from the air distribution valve seat (6b) protrudes relative to the air distribution valve seat (6b), the air distribution plane (6a3) is tightly attached to a switching plane (73) on the rotary valve (7), and the switching plane (73) protrudes from the rotary valve (7); the air distribution valve (6) is fixedly mounted in a mounting chamber of a cover (2), and the rotary valve (7) is rotatable around a principal rotation axis O of the rotary valve relative to the air distribution valve (6) to switch connection states of an air distribution side flow path and a switching side flow path. The cryogenic refrigerator includes the air distribution mechanism. The air distribution mechanism can avoid performing surface treatment on the rotary valve 7 to reduce costs, and only the rotary valve 7 is a moving component, to ensure the device stability.

A rotary valve of a cryocooler includes a valve stator, a valve rotor, a rotation member that rotates the valve rotor around an axis with respect to the valve stator, and a rotor holder connected to the valve rotor so as to rotate around an axis together with the valve rotor, and forming a low pressure section having a pressure lower than an ambient pressure between the valve rotor and the rotor holder so as to reduce an axial force of pressing the valve rotor against the valve stator. The rotation member is connected to the rotor holder so as to rotate the valve rotor around the axis via the rotor holder. The rotor holder is disposed between the rotation member and the valve rotor in an axial direction, and is movable in the axial direction with respect to the rotation member.

Disclosed are a self-pressure-relief air distribution mechanism and a corresponding cryogenic refrigerator. The self-pressure-relief air distribution mechanism includes an air distribution valve (6) and a rotary valve (7), where a rear face of the air distribution valve (6) is divided into a high-pressure face (66) and a low-pressure face (65), and the high-pressure face (66) and the low-pressure face (65) are hermetically separated by a third sealing ring (b3) that seals the air distribution valve (6) and a cover (2); and the air distribution valve (6) is provided with a pressure-relief hole (61) that axially penetrates an air distribution face (64) and the low-pressure face (65) of the air distribution valve (6), and a low-pressure passage (22) of the cover (2) can communicate with the rear face of the air distribution valve (6) via the pressure-relief hole (61), to guide a low-pressure airflow in the cover (2) to the rear face of the air distribution valve (6). The cryogenic refrigerator includes the self-pressure-relief air distribution mechanism. With the provision of the pressure-relief hole (61) and the third sealing ring (b3), the self-pressure-relief air distribution mechanism has a reduced pressure receiving area, thereby reducing a positive acting force and reducing wear.

A cryocooler includes: a housing furnished with a housing bottom surface; a displacer furnished with a displacer upper surface between the housing bottom surface and which an upper gas chamber is formed, and being enabled to reciprocate axially with respect to the housing; a housing gas flow path formed in the housing and opening onto the upper gas chamber; a displacer upper gas flow path formed in the displacer and opening onto the upper gas chamber; and a gas-guiding flow channel formed in at least either the housing bottom surface or the displacer upper surface constituting a portion of the upper gas chamber, and interconnecting the housing gas flow path and the displacer upper gas flow path when the displacer is positioned at top-dead center in its axial reciprocation.

An apparatus (1) for handling and cooling plastic preforms comprising a rotatable handling station (2), provided with a plurality of retaining and cooling pins (3) for preforms and adapted to cooperate with an extraction plate (4) adapted to extract the preforms from an injection mold; an aeraulic circuit (5) connected to said station and comprising an aspiration duct (6) for aspirating air from the inside of the station; a delivery duct (7) for sending air to said station; cooling means (8) arranged along the delivery duct for cooling the air sent to said station; aspiration means (9, 19, 29) connected at least to the aspiration duct and to the delivery duct, and wherein switching means are further provided, to pass from a first circuit configuration, in which there is an air passage from the delivery duct to the inside of the station, to a second circuit configuration in which there is an air passage from the inside of the station to the aspiration duct, whereby, in the first configuration, air is blown by means of the plurality of pins, while, in the second configuration, air is aspirated by means of said plurality of pins.

A GM cryocooler includes a compressor having a compressor discharge port and a compressor suction port, a displacer capable of reciprocating in an axial direction, a displacer cylinder accommodating the displacer, a drive piston connected to the displacer so as to drive the displacer in the axial direction, a drive chamber in which the drive piston is driven, a main pressure switching valve configured to alternately connect the displacer cylinder to the compressor discharge port and the compressor suction port, an auxiliary pressure switching valve configured to alternately connect the drive chamber to the compressor discharge port and the compressor suction port, and a buffer volume connected between the auxiliary pressure switching valve and the compressor.

A cryocooler includes a displacer capable of reciprocating in an axial direction, a cylinder that accommodates the displacer, a drive piston that drives the displacer in the axial direction, a drive chamber that accommodates the drive piston, a rotary valve that includes a first valve element that is one of a valve rotor rotatable around a rotary valve rotation axis and a valve stator, and a second valve element that is the other of the valve rotor and the valve stator, a reversible motor that is coupled with the rotary valve so as to rotate the rotary valve around the rotary valve rotation axis. The rotary valve includes a coupling mechanism that couples the first component and the second component with each other. The first relative angle is designed to cool the cryocooler, and the second relative angle is designed to heat the cryocooler.

A cryocooler includes a displacer, a cylinder that forms an expansion space, a Scotch yoke mechanism configured to drive the displacer in a reciprocating manner, a first rod that extends from the Scotch yoke mechanism, a housing that includes an assist chamber, a rotary valve configured to switch between a state in which the expansion space and a discharge side of a compressor are connected and the assist chamber and a suction side of the compressor are connected and a state in which the expansion space and the suction side of the compressor are connected and the assist chamber and the discharge side of the compressor are connected, a motor configured to drive the Scotch yoke mechanism and the rotary valve, and an on-off valve configured to open and close a gas flow path through which the rotary valve and the assist chamber are connected.