Abstract: Self-triggering cryogenic heat flow switches are used particularly with cooling systems that require a redundant operation. The self-triggering cryogenic heat flow switch has the simplest possible construction while providing a reliable, maintenance-free mode of operation, and ensures a self-switching connection between a heat sink and an end use device or application that is to be cooled. The heat flow switch includes an outer hollow cylinder 1 that is connected with a heat sink 9, and an inner body 2 that is arranged coaxially to the outer hollow cylinder 1 and connected to the end use device or application to be cooled. When the heat sink 9 is switched off, a concentric annular gap 4 fixed by spacers is provided between the hollow cylinder 1 and the inner body 2.

Abstract: A cooling apparatus especially for cooling high-temperature-superconducting lectronic components includes a cold gas cooling machine, such as a Stirling machine, thermally connected to a pressure vessel serving as a cold reservoir vessel. The pressure vessel contains a working medium having a triple point in the temperature range from about 60K to about 90K and a critical temperature at least as high as the maximum operating room temperature of the apparatus. The working medium is propane, for example. A cooling surface of the electronic component is thermally connected to the pressure vessel. In the method of operating the apparatus, the electronic component does not require continuous cooling. During a charging or refrigerating phase, the cooling machine freezes the working medium. Then during a useful cooling phase, the cooling machine is switched off and the electronic component is operated while being cooled by the frozen working medium.

Abstract: A refrigerant or coolant compressor of the radial type with an impeller hng a plurality of vane elements can be used for compressing water vapor as a refrigerant or coolant under vacuum conditions. The impeller of the compressor is constructed to produce a high volume flow rate at the required compression ratio, in view of the low density of water vapor as the preferred flow medium. The impeller has sufficient strength to operate at the required high circumferential velocities. The impeller includes vane elements, disk elements, vane support elements and a hub. The vane elements are individually connected to the hub by the support elements. The support elements may be either ring-shaped elements connecting a rear surface of the disk elements to the hub, or may be pin-shaped insert members connecting the root of each vane element to the hub. The components of the impeller are made of a polymer composite material reinforced preferably with carbon fibers.