Abstract: A counter flow heat exchanger comprising a plurality of tubes disposed in a bundle array or tube within tube configuration to enhance heat transfer between high and low pressure tubes in the array or tube in tube configuration. Also disclosed are a method of increasing the heat transfer capacity of a tube bundle heat exchanger and a liquid helium temperature refrigerator or a reliquefier utilizing the heat exchanger.

Abstract: A heat exchanger for a fast cooldown cryostat having high pressure and low pressure flow paths wherein a low pressure flow path is defined by a finely divided matrix which in turn defines a plurality of flow paths and said high pressure flow path is disposed in heat exchange relationshp to said matrix.

Abstract: A counter flow heat exchanger comprising a plurality of tubes disposed in a bundle array or tube within tube configuration to enhance heat transfer between high and low pressure tubes in the array or tube in tube configuration. Also disclosed are a method of increasing the heat transfer capacity of a tube bundle heat exchanger and a liquid helium temperature refrigerator or a reliquefier utilizing the heat exchanger.

Abstract: A counter flow heat exchanger comprising a plurality of tubes disposed in a bundle array or tube within tube configuration to enhance heat transfer between high and low pressure tubes in the array or tube in tube configuration. Also disclosed are a method of increasing the heat transfer capacity of a tube bundle heat exchanger and a liquid helium temperature refrigerator or a reliquefier utilizing the heat exchanger.

Abstract: A counter flow heat exchanger comprising a central low pressure return tube deformed intermediate its ends to enhance heat transfer capability wrapped by a high pressure tube to conduct fluid to an expansion device. Also disclosed are a method of increasing the heat transfer capacity of a tube bundle heat exchanger and a liquid helium temperature refrigerator or a reliquefier utilizing the heat exchanger.

Abstract: Enhanced thermal contact between axially aligned heat stations on a refrigerator and axially aligned heat stations on a device to be cooled wherein at least one of said heat stations on said device being cooled is allowed to move or float axially relative to the other heat station on said device being cooled to accommodate thermal contraction.

Abstract: A cryopump and method for using cryopumping to enhance the sensitivity of a leak detection system. The cryopump is used to control the relative pumping speeds of the gases normally frozen out on the pump or adsorbed in a cold adsorbent to thereby achieve the enhanced sensitivity of the system. The system is characterized by controlled access to the cold panel which is disposed within the warm panel.

Abstract: A counter flow heat exchanger comprising a central low pressure return tube deformed intermediate its ends to enhance heat transfer capability wrapped by a high pressure tube to conduct fluid to an expansion device. Also disclosed are a method of increasing the heat transfer capacity of a tube bundle heat exchanger and a liquid helium temperature refrigerator or a reliquefier utilizing the heat exchanger.

Abstract: A bakeable cryopump having a housing and means to removeably receive the displacer end of a cryogenic refrigerator to cool internal cryopanels said cryopumps adapted for removal of the refrigerator without loss of vacuum inside the cryopump and further adapted to be heated under vacuum to remove pumped gases primarily water so that the cryopumps after cooling can be used at vacuum of at least 10.sup.-10 Torr.

Abstract: An apparatus for condensing cryogen (e.g., helium) boil-off in a confined space such as the neck tube of a helium cryostat comprising a Joule-Thompson heat exchanger and valve disposed around a displacer-expander cryogenic refrigerator so the thermal gradient in the heat exchanger matches that of the refrigerator.

Abstract: A method and apparatus for increasing the refrigeration capacity of a displacer-expander type cryogenic refrigerator pneumatically actuated by a rotary valve by increasing the number of ports of the rotary valve to increase reciprocating speed of the displacer without increasing speed of rotation of the valve.

Abstract: Environmental gases, e.g. air are collected in an apparatus wherein a sample bottle containing a metering orifice for admitting the gas is contained within and cooled by a bath of liquid cryogen thus creating a partial vacuum inside the bottle to draw gas into the bottle where it is condensed and stored. The apparatus includes a source of cryogenic refrigeration disposed in an evacuated space above the liquid cryogen to condense liquid cryogen boil-off. By combining evacuation and cryogenic refrigeration the sample bottle holder can be rapidly cooled to operating temperature.

Abstract: A cryostat for maintaining an inventory of a liquefied cryogen including a vacuum jacketed reservoir (Dewar) containing heat shields in the vacuum jacket, the heat shields cooled to different temperatures and a cryogen recondenser cooled by a cryogenic refrigerator. Included in the cryostat is an access passage to place objects in the cryogen and to support the refrigerator, the access passage including means to remove the refrigerator without opening the liquid cryogen to ambient atmosphere.

Abstract: A cryopump consisting of cryopanels attached to an elongated source of refrigeration in which heat is transferred from cryopumping surfaces to various stages of refrigeration by conduction including a chevron baffle or louver mounted parallel to the long axis of the refrigerator source and directly to the warmest stage of refrigeration.

Abstract: A cryostat including a source of refrigeration disposed within an evacuated chamber containing a reservoir of liquified cryogen wherein refrigeration is directed to heat stations disposed in the access means to the reservoir to intercept heat leak into said reservoir and to recondense cryogen boil-off from said reservoir. Thermal convective couplings are used to cool the heat stations and to minimize heat leakage in the event the refrigeration source is disabled. Cryogen boil-off is condensed in an apparatus utilizing low thermal conductive conduits to direct the vapors to a refrigeration zone and return the condensed cryogen to the reservoir.

Abstract: A cryostat for producing an inventory of a liquefied working fluid by expansion of the working fluid through an orifice, the cryostat including means to rapidly cool the cryostat to operating temperature and to maintain fluid flow at low temperature and high working fluid pressure to maintain maximum heat transfer between the working fluid and an object being cooled by the cryostat.

Abstract: A cryostat for maintaining an inventory of a liquefied cryogen including a vacuum jacketed reservoir (Dewar) containing heat shields in the vacuum jacket, the heat shields cooled to different temperatures and a cryogen recondenser cooled by a cryogenic refrigerator. Included in the cryostat is an access passage to place objects in the cryogen and to support the refrigerator, the access passage including means to remove the refrigerator without opening the liquid cryogen to ambient atmosphere.

Abstract: Cryopumping speed of nitrogen, helium, hydrogen and neon can be increased by omitting the chevron baffle in a conventional cryopump and preventing incident radiation of about 300.degree. K. from striking surfaces used to cryosorb helium, hydrogen and neon. An apparatus is disclosed utilizing three pumping surfaces created from open ended opposed nested cylinders. A radiation absorbent coating is placed on one of the surfaces to shield the helium, hydrogen and neon pumping surface. Refrigeration can be provided by a two-stage closed cycle cryogenic refrigerator.

Abstract: A demand-flow cryostat wherein a refrigerant is supplied through an elongated heat exchanger disposed in a container and the refrigerant is expanded through a Joule-Thompson expansion orifice at one end of the heat exchanger to provide an inventory of liquid in the container at that end and wherein a valve member for controlling a refrigerant flow through the orifice is located adjacent thereto and is movable relative to the orifice; whereby a throttling movement is effected with a reduction in temperature. The operation of the orifice and valve member characterized in that each is affixed to separate mounting means, each of which mounting means is associated with a separate control element composed of different materials whose mean cryogenic linear coefficients of expansion differ by at least about 1.times.10.sup.-5 (.degree. K.sup.-1).

Abstract: Cryopumping speed of nitrogen, helium, hydrogen and neon can be increased by omitting the chevron baffle in a conventional cryopump and preventing incident radiation of about 300.degree. K. from striking surfaces used to cryosorb helium, hydrogen and neon. An apparatus is disclosed utilizing three pumping surfaces created from open ended opposed nested cylinders. A radiation absorbent coating is placed on one of the surfaces to shield the helium, hydrogen and neon pumping surface. Refrigeration can be provided by a two-stage closed cycle cryogenic refrigerator.