Applications—Cryogenic

It is often a requirement for industrial fabrications that once complete they are dried. The reason for this are as diverse as the applications it is used for but typical applications for drying include electrieal transformers, gas and liquid pipelines, thermal insulation and cryogenic applications. Drying through the application of vacuum allied with energy input is often the only solution. Drying with vacuum is... 

Copper retains high impact strength and increases its tensile strength under low temperatures, including cryogenic applications. Typical data are given in Table 3.17. 

Aluminum and its alloys are excellent for low temperatures as well as for cryogenic applications because their tensile strength and ductility are increased at low temperatures. 

They are widely employed in the manufacture, storage and distribution of liquified gases, particularly on sea and road tankers. The most popular alloy for cryogenic applications is 4.5% magnesium alloy (N8). Table 3.33 gives the boiling points of the most common cryogenic liquids and the minimum temperatures at which various materials can be used. 

Table 3.33. Aluminum Alloys Recommended for Cryogenic Applications...

Expansion Turbines for Energy Conversion and Cryogenic Applications, Atlas Copco, Bui. 2781005601, pub. date not known. 

The presence of liquid mercury poses a liquid metal embrittlement problem for many alloys. This occurs by the spillage of mercury in aircraft and the condensation of mercury vapor from mercury pumps in cryogenic applications. 

The low-temperature thermal conductivity of different materials may differ by many orders of magnitude (see Fig. 3.16). Moreover, the thermal conductivity of a single material, as we have seen, may heavily change because of impurities or defects (see Section 11.4). In cryogenic applications, the choice of a material obviously depends not only on its thermal conductivity but also on other characteristics of the material, such as the specific heat, the thermal contraction and the electrical and mechanical properties [1], For a good thermal conductivity, Cu, Ag and A1 (above IK) are the best metals. Anyway, they all are quite soft especially if annealed. In case of high-purity aluminium [2] and copper (see Section 11.4.3), the thermal conductivities are k 10 T [W/cm K] and k T [W/cm K], respectively. 

In the last decades, aluminium and aluminium alloys have received an increasing interest in cryogenic applications [5-7], Pure aluminium is used in the building of superconducting heat switches (see Section 4.3) because of its high switching ratio [8,9] and convenient critical field. Satisfactory procedures for welding have also been found [10,11],... 

We have seen that many electronic components, even not specifically produced for cryogenic applications, can be usefully operated at low temperature some of them retain their room temperature characteristics like NiCr resistors which do not appreciably change their resistance (less than 10% upon cooling to 4K) and show a lower noise at low temperature. Other resistors (as RuOz) and most capacitors change their characteristics with temperature. Mica and polyester film capacitors show a good temperature stability. If capacitors insensitive to temperature are needed, crystalline dielectric or vacuum capacitors must be used. 

Cryogenic applications, super-cold refrigeration components. .. 

Containers, vessels, process vessels, tank construction and linings, columns. .. Cryogenic applications, super-cold refrigeration components. .. 

At low temperatures, polyphenylene sulfide is used for cryogenic applications at -269°C. Generally, notched Izod impact strength does not significantly decrease between room temperature and -40°C. 

Aluminum also has a high degree of thermal and electrical conductivity. At low temperatures, the impact strength of aluminum increases, and for this reason, aluminum is commonly used in cryogenic applications. 

The ultrafine silicon carbide produced in an electric arc is used as an insulation in cryogenic applications (152) (see Cryogenics). It generally increases the wear resistance of the paint film when added to paint formulations. 

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