Abstract: A closed cycle refrigerating system for cryogenic temperatures using a single stage compressor with a refrigerant comprising a gas mixture. The refrigerating system includes a heat exchanger having a throttling orifice which is arranged to provide refrigeration, and a single stage oil lubricated compressor for compressing the refrigerant. The compressor is typically of the rolling piston type. The refrigerant is a mixture of at least one cryogenic gas having a normal boiling point below 120 degrees K and at least two other gases having normal boiling point temperatures below 300 degrees different from each other and from said one gas. There is also included means for cooling the compressed refrigerant and for circulating the cooled refrigerant to the heat exchanger and its throttling orifice and then back to the compressor. The system does not require any cascaded heat exchangers or intermediate phase separators.

Abstract: The throttling sensitivity of a demand flow cryostat may be controlled and stabilized by selectively exposing refrigerant to the surface of a sensor which actuates a refrigerant throttle valve. The sensor is formed of a plastic material such as high density polyethylene which has a high coefficient of thermal contraction.

Abstract: A cryostat in which a venting conduit is connected to a reservoir of the cryostat but no venting of cryogen within the reservoir can occur while fluid is flowing under pressure within the heat exchanger of the cryostat.

Abstract: A method and apparatus for cooling and filling a cryogen reservoir with liquid cryogen from the gas/liquid discharge of a heat exchanger. The cryogen reservoir has a cryogen liquid retaining material and a temperature sensing means remote from the heat exchanger. The gas/liquid discharge is located in a region within the reservoir proximate to the temperature sensing means. At least a portion of the discharge is passed through the liquid retaining material to be absorbed, thereby.

Abstract: A payload loaded into a chamber is cycled to a low temperature of about -320.degree. F. using liquid nitrogen fed to a heat exchanger evaporator that is located at the top of the chamber so that gaseous nitrogen vapor from the evaporator, at substantially the same temperature as the liquid nitrogen, is circulated to a payload in the chamber below, and, at the same time, gas from the chamber is circulated upward to highly thermally conductive fins on the heat exchanger that are cooled by the liquid nitrogen evaporation. Thus, heat from the payload is fed from the gas circulating upward to the heat exchanger to evaporate the liquid nitrogen and so the payload located at the bottom of the chamber is cooled by gas kinetics and is never touched by the liquid nitrogen.

Abstract: Thermal storage matrices, particularly useful in conjunction with the cooling of the infra-red detectors employed in space related or missile guidance systems are taught. Also taught are cryostat assemblies, including such thermal storage assemblies.

Abstract: A compact, portable cryogenic system for powering portable gas-driven tools having a container which includes an outer vacuum casing and an inner container with each having small, openings at their top connected together forming an evacuable space between the outer casing and the inner container. Material to inhibit heat transfer through the evacuable space is included in the space between the outer casing and the inner container. The openings of the inner container are closed with gas-tight closures fastened to the outer vacuum casing. The gas-tight closures can carry, through the single openings in the inner container, means to admit cryogenic liquid or withdraw cryogenic liquid from the inner container and means to admit heat to the inner container as may be desired. Warming coils positioned on the outer vacuum casing of the container communicate with the inner container and the flow of gas from the warming coils may be controlled by an adjustable pressure regulator.

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 cryogenic dewar includes openings at the top and bottom of the cryogenic fluid container. A valve is provided at the bottom of the container to control the flow of cryogenic fluid into and out of the container. The valve includes a valve body forming at least one passageway from the container to the opening at the container bottom and a valve seat therebetween. A valve closure is provided to engage and seal the valve seat. A rod, having the valve closure at its lower end, is supported by the body within the cryogenic fluid container and extends upwardly to adjacent the opening at the top of the container. A valve actuator for said rod is carried in an upper opening and is adapted to engage the rod at its upper end, to operate said valve closure, and to be removable from the upper opening.

Abstract: Apparatus for removal of flash from small molded plastic and rubber parts, including a specially configured cryogenic shaking vessel and support and drive means for imparting a reciprocating rotational movement thereto. In the preferred embodiment the generally elongated shaker vessel has rounded ends and bottom, and the vessel is oscillated about an axis perpendicular to the longitudinal axis of the vessel, so that a maximum mixing of the product and the deflashing media, which may be sharply pointed objects such as chrome plated tacks, occurs within the shaking vessel.