Abstract: An apparatus to provide a laminar curtain of dry gas over a cryogenic working surface includes a housing duct extending longitudinally from the working surface. A honeycomb member fills a section of the duct adjacent to the working surface, each honeycomb cell having a through channel in the longitudinal direction. A porous foam with through porosity fills a section of the duct adjacent to the honeycomb member oppositely from the working surface. A plenum is adjacent to the porous member oppositely from the honeycomb. Dry gas is supplied to the plenum to flow through the foam and honeycomb to effect the laminar curtain.

Abstract: A cryogenic bypass current lead to bypass quenched magnets in a string of magnets in a superconducting super collider comprises a HTSC section interposed between a lower conductive body terminal and the conductive of the lead is described.

Abstract: A MRI cryostat, which contains a superconducting magnet operating in a bath of liquid helium, reduces the boil-off rate of helium by intercepting most of the heat in-leakage by means of a throttle cycle (TC) refrigerator operating at a low side temperature of about 90K. The main heat exchanger for the throttle cycle refrigerator is located within or immediately adjacent to the cryostat housing and delivers cold liquid to a cold heat exchanger that is in thermal contact with an outer radiation shield, support struts, neck tube and electrical leads inside the cryostat. Heat is intercepted by the outer shield from essentially all paths between a 300K ambient and a 4K load temperature, which temperature results from liquid helium boil-off to atmosphere. A second, inner radiation shield at 35K is cooled by gaseous helium that boils from the liquid helium bath. There are no moving parts of the refrigeration system in the cryostat. Thus, vibration, noise and disturbance of the magnetic field are reduced.

Abstract: Superconducting magnet and regenerative refrigerator can be reduced in size of the apparatus and is capable reducing the evaporating amount of liquid helium. A coil portion second thermal shield 17a and a coil portion thermal shield 8a are disposed so as to enclose a coil portion helium tank 2a which contains superconducting coil 1. Further, a helium portion second thermal shield 17b and a helium reservoir portion thermal shield 8b are disposed so as to enclose a helium reservoir tank 2b which stores liquid helium 3. A coil portion second thermal shield 17a and a coil portion thermal shield 8a are cooled by a coil portion 2-stage type Gifford-McMahon cycle refrigerator 50a while a helium portion second thermal shield 17b and a helium reservoir portion thermal shield 8b are cooled by a helium reservoir portion 2-stage type Gifford-McMahon cycle refrigerator 50b.

Abstract: An object of the present invention is to obtain a superconductive magnet, the size of which can be reduced by shortening the radial length of a magnetic device thereof and the refrigerating performance of which can be improved. A cylinder for fastening a refrigerator has an end facing an ambience of helium gas evaporating in a helium chamber and another end which is substantially horizontally fastened to a vacuum chamber. Further, the three-stage regenerative refrigerator is inserted and fastened to the cylinder for fastening the refrigerator. A heat insulator, such as a convection prevention tube, made of a hollow Teflon tube is wound around the outer surface of each stage of the cylinder of the three-stage regenerative refrigerator. The convection prevention tube is enclosed into a gap between the cylinder for fastening the refrigerator and the three-stage regenerative refrigerator without no undesirable gap so that heat convection of the helium gas is prevented.

Abstract: A closed cycle cryogenic refrigerating system with a fixed restrictor operates with a compressor inlet pressure in a range of 0.1 Mpa to 0.4 Mpa and compressor discharge pressure in a range of 1.5 Mpa and 2.5 Mpa. A basic cryogenic refrigerant mixture is used to which is added approximately 3% to 25% of helium, hydrogen and/or neon. A ratio of refrigerant density at the inlet of the fixed restrictor between steady-state operation and operation at the beginning of cool-down is in an approximate range of 7 to 17. Relatively rapid cool-down is achieved and evaporator temperature is maintained in an approximate range of 70K to 120K.

Abstract: An open magnetic resonance imaging (MRI) magnet having first and second spaced-apart superconductive coil assemblies each including a toroidal-shaped coil housing containing a superconductive main coil in thermal contact with a cryogenic fluid contained in a dewar. Preferably, each main coil is located outside of and in solid-conduction thermal contact with its corresponding dewar (instead of inside the dewar). Preferably, a surrounding single (not double) thermal shield is cooled by liquid cryogen boil-off or by a cryocooler coldhead. All this allows the main coil to be located closer to the magnet's open space which reduces magnet cost by reducing the amount of coil needed for the same-strength magnetic field.

Abstract: A short-term thermally stable cryostat (40). The cryostat (40) pre-cools an incoming high-pressure gas, converts the gas to a cold liquid, and cools an item by allowing the liquid to acquire heat from the item and boil into an exhaust gas, while maintaining a constant flow rate of the exhaust gas to reduce thermal noise due to flow rate modulation. The cryostat (40) includes an evacuated space (58) therein containing the item to be cooled and an inner cooling volume (64). Pre-cooling fins (44) spiral around a hollow mandrel (52) within the cooling volume (64) and circulate an incoming high-pressure gas around the mandrel (52). A flow restrictor (60) receives the incoming gas from the pre-cooling fins (44) and releases it into the cooling volume (64), thereby convening the incoming gas into a cold liquid which can acquire heat from the item and boil into an exhaust gas.

Abstract: A thermodynamic engine comprises first and second heat exchange members and a solid state thermodynamic member therebetween. At least one of the heat exchange members is formed by use of micromechanical machining.

Abstract: An open magnetic resonance imaging (MRI) magnet having longitudinally spaced-apart superconductive main coils surrounded by a dewar containing a cryogenic liquid (e.g., liquid helium) and boiled-off cryogenic gas (e.g., helium vapor). A condenser is in physical contact with the boiled-off vapor and is in thermal contact with a cold stage of a cryocooler coldhead so as to re-liquefy the vapor. This allows the coils to be surrounded by a single (not double) thermal shield which allows the coils structurally to be located closer to the magnet's open space which reduces magnet cost by reducing the amount of coil needed for the same-strength magnetic field.

Abstract: A superconducting magnet is arranged in a helium tank, and the superconducting magnet cooled to a very low temperature by liquid helium in the helium tank is connected to a power source kept at room temperature by a current lead and a current lead. The current leads are constituted by conductors made of copper or a copper alloy having a residual resistivity of 5.times.10.sup.-8 .OMEGA..multidot.m or more. In a helium tank, a persistent current switch, cooled by liquid helium, for connecting the conductor to the conductor, is arranged. The persistent current switch magnetizes the superconducting magnet to a persistent current mode and demagnetizes it from the persistent current mode. The helium tank is arranged in a vacuum housing.

Abstract: A super conducting magnet system for magnetic resonance systems comprising at least one radiation shield. Temperature sensors, an external refrigeration system and a controller are provided for maintaining said at least one shield at a constant temperature by heating the shield and reducing the heat provided as the refrigerator system wears or by increasing the frequency of the refrigeration cycle as the system wears or both.

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: A sample holding device (30) for a dilution refrigerator having a still (16), a mixing chamber (22), and a heat exchanger (26) connected between the still and mixing chamber whereby coolant flows from the still to the mixing chamber and from the mixing chamber to the still through respective first and second adjacent paths in the heat exchanger and wherein the mixing chamber has a tubular portion (27), the sample holding device comprising a tube for insertion in the tubular portion of the mixing chamber and having means (34) for holding a sample within the tubular portion, the tube having an aperture (36) adjacent the sample holding means communicating in use between the interior of the tube and the interior of the tubular portion and another aperture (37) positioned in use to communicate between the interior of the tube and the second path in the heat exchanger.

Abstract: A cryostat assembly having an outer vessel within which is provided substantially upright inner vessel for containing an item, such as an electromagnet, to be cooled. The inner vessel is suspended from the outer vessel by a number of low thermal conductivity support members secured at one end to points on the outer vessel corresponding to the height of the center of gravity of the assembly and an item in use and at the other end to the inner vessel at points not higher than the said points on the outer vessel.

Abstract: The present invention provides a system and method for freezing and cutting a tissue specimen for medical diagnostic purposes which comprises a specimen block holder for holding the tissue specimen; an embedding medium; a freezing plane for providing direct metal contact freezing of the specimen; a knife blade comprising a cutting edge which is substantially parallel to and may be displaced a preset distance from the freezing plane; a block holder for holding the specimen; and driving means for transporting the block holder towards the freezing plane for creating a flat frozen surface of the specimen having a thickness t and also for transporting the frozen specimen past the knife edge to provide a section having a desired thickness. The planar relationship and known distance between the freezing plane and the cutting edge together will be used as the basis for calculating frozen thickness t of the specimen. This allows for precise and automated movement of the block holder for trimming.

Abstract: A superconducting device, such as a superconducting rotor for a generator or motor or a superconducting magnet for a magnetic resonance imaging machine, etc. A vacuum enclosure surrounds and is spaced apart from a superconductive coil. Apparatus supports the coil in the enclosure during operation of the device, such apparatus including a first thermally insulative honeycomb assemblage positioned between the coil and the enclosure. In a first preferred construction, the first honeycomb assemblage is positioned between and connected to the coil and a thermal shield, and a second honeycomb assemblage is positioned between and connected to the shield and the enclosure. In a second preferred construction, the second honeycomb assemblage is replaced with a first suspension strap.

Abstract: A superconductive magnet having a superconductive coil located within a thermal shield located within a vacuum enclosure. A magnet re-entrant support assembly includes an outer support cylinder located between the vacuum enclosure and the thermal shield and includes an inner support cylinder located between the thermal shield and the superconductive coil. The outer support cylinder's first end is rigidly connected to the vacuum enclosure, and its second end is rigidly connected to the thermal shield. The inner support cylinder's first terminus is rigidly connected to the thermal shield near the outer support cylinder's second end, and its second terminus is located longitudinally between the outer support cylinder's first and second ends and is rigidly connected to the superconductive coil. Buckling resistance is improved by adding stiffening rings to the support cylinders.

Abstract: Lead-in module for the supply of a low critical temperature superconducting electric loadThe module (3) is located inside a cryostat (1), it is fixed to its sealing cover (2) and it comprises a pair of metal conductors (6, 7) which pass through the cover (2) and whose lower ends are connected to the upper end of a high critical temperature superconducting module (8) comprising two conductors (9, 10) electrically connected to said pair of metal conductors (6, 7) and separated by an insulating core (11) making up a mechanical reinforcement, with an insulating structure (14) whose upper end (15) is fixed to the bottom of said cover (2) of the cryostat (1), surrounding the pair of metal conductors (6, 7) in a sealed manner until its junction (16) with the superconducting module (8), the structure (14) extending in an unsealed manner until at least the lower end of the superconducting module (8), the structure (14) comprising at its lower end fastening means (20) to support the electric load (4).

Abstract: A positive retraction mechanism for cryogenic thermal joints including deformable interfaces to separate joints which have cold welded utilizing a moveable enclosing sleeve and an actuating mechanism including the force of a compressed bellows to move a retraction flange into engagement with retraction rods which force the thermal joint apart through controlled movement of the retraction flange.

Abstract: A cryogenic cooling system includes a cryocooler coldhead having a cold stage. A gas circulator has a low pressure input orifice and a high pressure output orifice, and a valve has a primary port and a secondary port. The valve makes and switches fluid connections between the valve's primary and secondary ports and the gas circulator's input and output orifices. A heat exchanger has a primary portion and a secondary portion each in thermal contact with the cold stage. The primary (secondary) regenerator is positioned between the primary (secondary) port of the valve and the primary (secondary) portion of the heat exchanger. A coolant flow path has a first end in fluid communication with the heat exchanger's primary portion and a second end in fluid communication with the heat exchanger's secondary portion. The coolant flow path may be placed in thermal contact with a superconductive device.

Abstract: A thermally conductive feedthrough has a conductive member extending through a fiber-reinforced plastic plate. The feedthrough is sealed against leakage from one side of the plate to the other by placing the plate in local compression to seal it against the plate and/or by using small individual conductive members that minimize the effects of thermal expansion differences. The feedthrough can be used between vacuum and cryogenic liquids.

Abstract: A refrigeration system includes a dewar and a refrigerator/liquefier which meets the variable demands of a superconducting magnet within the dewar. The system is sized to meet average loads over a defined duty cycle, and is variably operable to meed demands. In the preferred embodiment, a first supply of fluid circulates through a "condenser" element positioned in a dewar ullage to liquefy a separate supply of fluid in the dewar, and to refrigerate a pulsed cryogenic load therein, such as a superconducting magnet. A portion of the first supply of fluid may be diverted to refrigerate a second pulsed cryogenic load, such as magnet current leads permanently connected to the magnet. The dewar includes a cold gas vapor storage chamber separate from the dewar ullage, and the chamber is preferably located within the inner core of a solenoid superconducting magnet for compact and thermally efficient design. Responsive, independent adjustment of refrigeration to pulsed cryogenic loads is made possible.

Abstract: To vitrify a sample, for example a biological sample which has a high water content, without the formation of ice crystals, the sample (10) is placed in a closed test chamber (11) having a chamber outlet (35). The chamber (11), with the sample therein, is filled with a primary fluid without cooling the sample to freezing temperature. This primary fluid may be an alcohol. The sample is vitrified by applying a high-pressure cryogenic fluid against the sample at a substantial pressure. The step of maintaining the pressure is accomplished, in accordance with the invention, by maintaining the outlet (35) from the chamber (11) at least essentially closed by a closing element, typically a valve (41), until the pressure within the sample chamber (11) has reached a predetermined value. The primary fluid may be a portion of the cryogenic fluid itself, for example heated, or even cooled, to an appropriate temperature which, however, will not cause the sample to freeze.

Abstract: A thermally conductive feedthrough has a conductive member extending through a fiber-reinforced plastic plate. The feedthrough is sealed against leakage from one side of the plate to the other by placing the plate in local compression to seal it against the plate and/or by using small individual conductive members that minimize the effects of thermal expansion differences. The feedthrough can be used between vacuum and cryogenic liquids.

Abstract: A matched thermal expansion support system for cryogenically cooled x-ray spectrometers is described for the purpose of holding x-ray detecting crystals precisely in position throughout large temperature changes. This thermal matching is achieved by a detector holder, having an axial thermal movement characteristic, mounted on a support having an equal, but opposite, thermal movement characteristic.

Abstract: A cooling system for a superconductive magnet. A cryocooler coldhead and a compressor are remotely located from the magnet. A helium-gas conduit circuit has five helium-gas paths. The first path extends from the compressor's outlet port to being in proximate thermal contact with the coldhead's first stage. The second path extends from there to being in proximate thermal contact with the coldhead's second stage. The third path extends from there to being in proximate thermal contact with the magnet's superconductive coil. The fourth path extends from there to being in proximate thermal contact with the magnet's thermal shield. The fifth helium-gas path extends from there to the compressor's inlet port.

Abstract: A vapor compression system having a mixing and distributing unit mounted in the refrigerant circuit between the system expansion valve and evaporator. The unit includes a mixing vane and a nozzle for directing a uniformly distributed two phase mixture into the evaporator.

Abstract: A method and an apparatus for cooling an superconducting material below the boiling point of liquid nitrogen by using liquid nitrogen as coolant. The cooling method of the invention can be used in two different modes, one under reduced pressure and the other under the atmospheric pressure. The former comprises a coil container which is in fact a vacuum vessel and the temperature of which is lowered by to the triple point of nitrogen by means of a vacuum pump. The latter comprises a coil container containing therein a cooling section of a freezer and the temperature of the coil container is lowered to the melting point of nitrogen by the freezer.

Abstract: A packaging apparatus used to store semiconductor devices with a coolant without contaminating the semiconductor devices. The apparatus has an enclosure which is evacuated at room temperature and then cooled in an atmosphere of coolant gas until the gas condenses and the enclosure is partially filled with liquid. The enclosure is then heated to allow the liquid to evaporate and a thermally activated mechanism to trap pure cold gas inside the enclosure. The trapped gas increases internal pressure which maintains a tight seal of the trapping mechanism against a gasket.

Abstract: Device for dehydrating and/or embedding preferably frozen samples, comprising a Dewar vessel (1) filled with liquid nitrogen (2) and a metallic element (4), anchored to the floor (3), of material of good thermal conductivity, which exhibits at its upper end in the region of attachment of the Dewar neck a cover (5) with a metallic cooling surface (6, 7) which corresponds with the complementarily designed lower contact surfaces of the thermostatically heated (9, 10) substitution (PLT) containers (8) or respectively of the lower part of a freeze-drying chamber in a manner which ensures a good heat transfer between the corresponding surfaces.

Abstract: A cryogenic package provides a cryogenic environment for devices that require temperatures of 150 K or below, with uniform cooling and minimal thermal stress. A cryocooler produces cold gas on a closed loop, and the gas is distributed in the chamber of a cryogenic vessel. The device housed in the chamber is bathed in a continuous flow of the gas. The warmed gas is returned to the cryogenic cooler.

Abstract: An apparatus for dispensing a cryogenic liquid includes means for focusing a beam of energy, eg. laser energy from a source onto the liquid cryogen as it passes through an outlet from a cryogenic liquid container.

Abstract: A device and method for cryogenic cooling of electronic components. A mixture of a first non-condensible gas and a second condensible gas is provided within an insulative housing. The non-condensible gas mixture has a partial pressure equal to the desired saturation pressure of the condensible gas. The insulative housing also includes an immersion chamber for housing electronic components. The immersion chamber preferably comprises two retainer parts and provides an module retainer top and a lower coldplate retainer bottom. The module retainer top allows gas to pass through the module retainer portion freely. The condensible gas is then turned into liquid form by a provided condensing means. The condensed liquid thus forms and collects inside the immersion chamber against the coldplate retainer bottom to cool the electronic components placed within. The non-condensible gas permits the condensed liquid to be subcooled.

Abstract: Apparatus and methods for cooling a superconducting magnet by circulating a pressurized helium gas through a convective cooling loop by natural convection, and apparatus and methods have been provided for quickly and effectively cooling a warm superconducting magnet down to operating temperature.

Abstract: In a cryostat, an isothermal boundary is proximate a large plurality of devices that are being cooled. The barrier is slightly colder than the devices so that heat flux therebetween is very small. The devices are in good thermal contact with a cold plate, which is made of a high thermal conductivity material. A single heater and a temperature sensor control the temperature of the cold plate as heat flows from the cold plate to the isothermal boundary. By limiting heat flow from the cold plate, temperature gradients throughout the temperature controlled region are very small. All of the devices to be cooled are very close to the same temperature. The isothermal boundary is maintained at the desired temperature by a flow of cryogenic refrigerant and a temperature sensor on the isothermal boundary provides inputs to a controller of refrigerant flow. The cryostat is constructed to minimize the amount of energy required from the heater to maintain the temperatures, and to minimize refrigerant flow.

Abstract: A cryogenic heat exchange system and freer dryer incorporating the same. The cryogenic heat exchange system has a heat exchanger provided with at least one pass for receiving a cryogenic heat exchange fluid. A reversing circuit is provided to reverse the flow direction of the cryogenic heat transfer fluid in the at least one pass to help prevent asymmetric ice buildup on the heat exchanger. Additionally, a portion of the spent cryogenic heat transfer fluid after having passed through the at least one pass is recirculated. During the recirculation, the spent cryogenic heat transfer fluid is mixed with incoming cryogen to produce the cryogenic heat transfer fluid. Such cryogenic heat transfer fluid after creation is then introduced into the flow reversing circuit and the one or more passes of the heat exchanger. A remaining portion of the cryogenic heat transfer fluid is vented. The recirculation raises the temperature of the heat transfer in the heat exchanger to also promote uniform ice buildup.

Abstract: A two-way flow solenoid-controlled expansion valve and receiver assembly for a two-way flow heat transfer system employing a refrigerant comprises a receiver and a valve body mounted on the receiver having two inlet/outlet passages. Either one of the inlet/outlet passages may be connected to a heat exchanger that switches from a condensing mode to an evaporative mode on refrigerant flow reversal while the other of these passages is then connected to another heat exchanger that operates in opposite manner. The inlet/outlet passages are each adapted to receive refrigerant from a condensing heat exchanger and deliver same through a separate check valve to the receiver and a flow control valve arrangement including two flow control valves independently operated by a proportional solenoid is operable to route and regulate refrigerant flow from the receiver to the other inlet/outlet passage that is connected to the heat exchanger that is then in an evaporative mode.

Abstract: Disclosed is an improved method for freezing biological specimens, such as human tissues, animal tissues, and plant tissues. The specimens are frozen so that they may be presently examined with light microscopy, or first stored frozen at ultra low temperatures and then later examined with light microscopy. The specimens are prepared with a matrix gel and then frozen with a fluorinated carbon fluid that is non-toxic to humans and thus the method does not present adverse health effects to humans. Preferably, the fluid also is non-flammable. More preferably, the fluid also has an ozone depletion potential of 0, whereby the preferred procedure is free of detrimental effects on the protective ozone layer of the earth. A suitable fluorinated carbon fluid is one that stays in the liquid state at low temperatures, for instance -60.degree. C. or lower. A suitable material is the perfluorinated carbon fluid, C.sub.6 F.sub.14.

Abstract: A cryogenic refrigerator includes a first refrigerant filled in a final refrigerating force storage chamber on a high temperature side thereof and consisting essentially of a composition expressed by (a) (Er.sub.(x) R.sub.(1-x)).sub.3 Ni.sub.(y) Co.sub.(1-y), or (b) Er.sub.(x) R.sub.(1-x) Ni.sub.(y) Cu.sub.(1-y) wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, and R denotes a rare earth element selected from the group consisting of Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb and Sc, a second refrigerant filled in the final refrigerating force storage chamber on a low temperature side thereof and consisting essentially of a composition expressed by (f) Er.sub.(x) R.sub.(1-x) Ni.sub.(y) Co.sub.(1-y), or (g) (Er.sub.(x) R.sub.(1-x)).sub.3 AlC.sub.(y) wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.

Abstract: A superconductive magnet having a superconductive coil located within a thermal shield located within a vacuum enclosure. A cryocooler coldhead's first stage is in solid-conductive thermal contact with the thermal shield, and its second stage is in solid-conductive thermal contact with the superconductive coil. A magnet re-entrant support assembly includes an outer support cylinder located between the vacuum enclosure and the thermal shield and includes an inner support cylinder located between the thermal shield and the superconductive coil. The outer support cylinder's first end is rigidly connected to the vacuum enclosure, and its second end is rigidly connected to the thermal shield. The inner support cylinder's first terminus is rigidly connected to the thermal shield near the outer support cylinder's second end, and its second terminus is located longitudinally between the outer support cylinder's first and second ends and is rigidly connected to the superconductive coil.

Abstract: A cooling system for a superconductive magnet. A dewar, located outside the magnet, includes a vacuum jacket hermetically connected to the magnet's vacuum enclosure and includes liquid helium located within the vacuum jacket. A thermal busbar is located within and spaced apart from the hermetically connected vacuum jacket and vacuum enclosure. The thermal busbar has a first end located within the vacuum jacket and a second end located within the vacuum enclosure and in thermal contact with the magnet's superconductive coil. A cryocooler coldhead, located outside the vacuum enclosure, has a housing located outside the vacuum jacket and has a cold stage extending from the housing to inside the vacuum jacket to re-liquefy any helium boiled-off in cooling the magnet 10.

Abstract: A plurality of cryopumps are installed in each of a plurality of neutral beam injection apparatuses disposed around a nuclear fusion apparatus.The cryopanels of each of the cryopumps are refrigerated by a small helium refrigerating machine. Since the cryopanels are refrigerated from room temperature with cold liquid nitrogen used for refrigerating a heat shield plate, then a small helium refrigerating machine and finally cold liquid helium itself, various valves and a small helium refrigerating machine are disposed. This permits refrigeration of a plurality of cryopumps within a short time, thereby saving the power consumption and improving the operating reliability of a refrigeration system.

Abstract: A self-contained device for the supply of energy to an apparatus (7) driven by gas under pressure, comprises a portable reservoir (1) of cryogenic liquid, and structure associated with the reservoir to withdraw and vaporize liquid from the reservoir and to send it to the apparatus (7). Two circuit portions (2.sub.1, 2.sub.2) incorporate vaporizers (5.sub.1, 5.sub.2) and are delimited between non-return valves (4.sub.1, 4.sub.2) upstream and control valves (6.sub.1, 6.sub.2) downstream. When open, the control valves drive the apparatus (7). The reservoir (1) is of the double wall type (1.sub.1, 1.sub.2), at least one upstream part of the circuit portion (2.sub.1, 2.sub.2) being disposed between these walls (1.sub.1, 1.sub.2). The two circuit portions are in parallel (2.sub.1, 2.sub.2) and the respective valves (6.sub.1, 6.sub.2) are sequentially controlled by a control device (9, 12) which is sensitive to the pressure (P.sub.1, P.sub.2) prevailing in the circuit portions (2.sub.1, 2.sub.2).

Abstract: An apparatus for transferring liquid helium between axially spaced first and second endpieces, being fixed thereto at opposite ends and having an intermediate insulative portion. An outer conduit of larger diameter concentrically surrounds the internal cryogen delivery conduit and also extends between and is fixed at opposite ends to the two endpieces. The outer conduit has an insulative portion, with the insulative portions of the internal cryogen delivery conduit and the outer conduit electrically insulating the first endpiece from the second endpiece. An annular space between the internal cryogen delivery conduit and the coaxial outer conduit is subject to vacuum pressure via a pumping passage within one of the endpieces which connects to that annular space and which may be connected to a pump for providing the vacuum within that space. Fins are disposed about the periphery of the coaxial outer conduit.

Abstract: A thermally conductive feedthrough has a conductive member extending through a fiber-reinforced plastic plate. The feedthrough is sealed against leakage from one side of the plate to the other by placing the plate in local compression to seal it against the plate and/or by using small individual conductive members that minimize the effects of thermal expansion differences. The feedthrough can be used between vacuum and cryogenic liquids.

Abstract: A chamber system for cryosorption freeze-drying of biological specimens in a Dewar vessel, comprises a chamber having a cylindrical metal wall and fitted within the Dewar vessel, a lower outer edge of which chamber is connected in a vacuum-tight manner to a lower edge of a metallic rotational component, the metallic rotational component having a bottom contact surface, which bottom contact surface corresponds with a complementary top contact surface on top of a cylindrical body around which liquid nitrogen flows and cools the metallic rotational component, the rotational component having a chamber to receive a drying agent for conducting cryosorption, for example a molecular screen, as well as a connection to the drying chamber.The upper edge of the metal wall or a ring connected thereto in a vacuum-tight manner is situated outside the Dewar vessel and is therefore approximately at ambient temperature and has a vacuum connection for the connection of commercially available vacuum components.

Abstract: A vacuum vessel has a member to be cooled to a low operating temperature inside the vacuum vessel and a main cooling circuit having fluid for cooling the member to operating temperature. The main cooling circuit has first fluid refrigerating means located at the vacuum vessel. To achieve rapid cooling, there is a pre-cooling circuit having the fluid for pre-cooling the member towards the operating temperature. The pre-cooling circuit has second fluid refrigerating means operating independently of the first fluid refrigerating means. The pre-cooling circuit cools the main cooling circuit, prior to operation of the main cooling circuit, by passage of the fluid from the pre-cooling circuit into the main cooling circuit. A heat shield cooling circuit for cooling a heat shield cools the second fluid refrigerating means of the pre-cooling circuit.

Abstract: For use with a heat exchange system having a compressor, condenser, evaporator, expansion device, and circulating refrigerant, an efficiency enhancing apparatus. Comprising the apparatus is a liquid refrigerant containing vessel having a refrigerant entrance and a refrigerant exit with the vessel positioned in the heat exchange system between the condenser and the evaporator. Included are means associated with said vessel for creating a turbulent flow of liquefied refrigerant.

Abstract: An infrared detector wherein an infrared detecting device can be cooled efficiently without increasing thermal stresses generated in the device body owing to cooling during the operation of the detector, and intrusion of ambient light can be prevented. A container for the infrared detecting device, which includes a bottom plate having a projection formed in the center thereof, is provided on an inner end portion of an inner cylinder constituting a dewar, and the infrared detecting device is placed on and secured to the projection of the bottom plate. The container bottom plate is made of an Invar, while the end portion of the inner cylinder is made of a Kovar or an Invar.