Abstract: A cryogenic cooling apparatus is provided, wherein the degree of freedom of installation and use is increased without deteriorating the reliability or stability and the range of uses of the apparatus is also increased. A coil unit and a refrigeration unit are positioned such that a second heat conductive member disposed on an extendible wall of a vacuum container and a fourth heat conductive member disposed on an extendible wall of another vacuum container face each other coaxially. In this state, the coil unit and refrigeration unit are relatively moved to approach each other, and thus the second heat conductive member and fourth heat conductive member come in contact. If the coil unit and refrigeration unit are further moved, the extendible wall extends and consequently the second heat conductive member comes in contact with a first heat conductive member. In addition, the extendible wall contracts and consequently the fourth heat conductive member comes in contact with a third heat conductive member.

Abstract: A superconducting magnet apparatus comprises a superconducting coil unit, and a refrigerant-filled chamber type refrigerator having a plurality of cooling stages. At least a final cooling stage of the cooling stages includes a static-type refrigerant-filled chamber and is associated with the superconducting coil unit, and at least a first cooling stage of the cooling stages includes a movable-type refrigerant-filled chamber.

Abstract: The present invention provides a pulse tube refrigerator, comprising a regenerator having an inlet port and an outlet port, a pulse tube having one end portion connected in series to the outlet port of the regenerator, a gas compressor connected to the inlet port of the regenerator, a first valve disposed between the discharge port of the gas compressor and the inlet port of the regenerator, a second valve disposed between the suction port of the gas compressor and the inlet port of the regenerator, a first valve controller for selectively opening/closing alternately the first and second valves to permit a high pressure coolant gas discharged from the discharge port of the gas compressor to be guided into the pulse tube through the regenerator and, then, to permit said coolant gas to be sucked into the gas compressor through the suction port thereof via the reverse passageway so as to generate coldness, a third valve disposed between the other end portion of the pulse tube and the discharge port of the gas co

Abstract: The present invention provides a pulse tube refrigerator, comprising a regenerator having an inlet port and an outlet port, a pulse tube having one end portion connected in series to the outlet port of the regenerator, a gas compressor connected to the inlet port of the regenerator, a first valve disposed between the discharge port of the gas compressor and the inlet port of the regenerator, a second valve disposed between the suction port of the gas compressor and the inlet port of the regenerator, a first valve controller for selectively opening/closing alternately the first and second valves to permit a high pressure coolant gas discharged from the discharge port of the gas compressor to be guided into the pulse tube through the regenerator and, then, to permit said coolant gas to be sucked into the gas compressor through the suction port thereof via the reverse passageway so as to generate coldness, a third valve disposed between the other end portion of the pulse tube and the discharge port of the gas co

Abstract: In a process for producing a plate-like polystyrene resin foam which comprises extruding a molten mixture consisting of a polystyrene resin and a volatile blowing agent by an extruder into a zone having a lower pressure than the inside of the extruder; the improvement wherein said volatile blowing agent is a mixture consisting of dichlorodifluoromethane, ethyl chloride and methyl chloride in which dichlorodifluoromethane accounts for 50 to 70% by weight of the mixture and the remainder consists of ethyl chloride and methyl chloride and the amount of ethyl chloride is at least 30% by weight based on the total amount of ethyl chloride and methyl chloride; and wherein said volatile blowing agent is present in said molten mixture in a proportion of 8 to 17 parts by weight per 100 parts by weight of the polystyrene resin component.

Abstract: In a method for producing a plastic foam of a desired expanded dimension which is constituted by extruding a melt of a thermoplastic synthetic resin containing a blowing agent through a die of an extruder and passing the extrudate through a shaping device located outwardly of the extruder and secured to the discharge end of the extruder while expanding and solidifying the molten mass so that it fills the shaping device; the improvement wherein at least a part of that area of the inside surface of the shaping device with which the expanded resin makes contact is formed of a plate of a fluorocarbon resin, said plate being secured to the inside surface of the shaping device by fitting portions, said fitting portions having a sufficient space for absorbing an increase in the volume of the fluorocarbon resin plate at the temperature of extrusion molding; and an apparatus for use in the above described process.

Abstract: A foamed polystyrene board useful as a thermal insulating material is produced by melting a polystyrene having a melt index of from 0.5 to 5 under heat in an extruder, mixing the molten mass with a blowing agent composed of methyl chloride and dichlorodifluoromethane, and extruding the resulting foamable molten gel from the extruder. As a novel essential feature, a flowability improver having a melting point higher than 70.degree. C., such as an aromatic sulfonamide, a brominated aromatic compound, a brominated alicyclic compound or a poly(.alpha.-methylstyrene), is mixed with the polystyrene within the extruder to impart superior extrusion formability. The foam has good dimensional stability both at room temperature and higher temperature, high mechanical strength and superior thermal insulation properties.