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Nitrogen is a liquid under −195.8 °C (77.3 K).. In physics, cryogenics is the production and behaviour of materials at very low temperatures.. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (−153 °C) to ...
Cryogenic machining is a machining process where the traditional flood lubro-cooling liquid (an emulsion of oil into water) is replaced by a jet of either liquid nitrogen (LN2) or pre-compressed carbon dioxide (CO 2). Cryogenic machining is useful in rough machining operations, in order to increase the tool life.
The term is most often used for smaller systems, typically table-top size, with input powers less than about 20 kW. Some can have input powers as low as 2–3 W. Large systems, such as those used for cooling the superconducting magnets in particle accelerators are more often called cryogenic refrigerators. Their input powers can be as high as 1 MW.
A 3 He/ 4 He dilution refrigerator is a cryogenic device that provides continuous cooling to temperatures as low as 2 mK, with no moving parts in the low-temperature region. [ 1 ] [ 2 ] The cooling power is provided by the heat of mixing of the helium-3 and helium-4 isotopes.
A cryogenic processor is a device engineered to reduce the temperature of an object to cryogenic levels, typically around −300°F (−184.44°C), at a moderate rate in order to prevent thermal shock to the components being treated. The inception of commercial cryogenic processors dates back to the late 1960s, pioneered by Ed Busch. [1]
Cryogenic grinding, also known as freezer milling, freezer grinding, and cryomilling, is the act of cooling or chilling a material and then reducing it into a small particle size. For example, thermoplastics are difficult to grind to small particle sizes at ambient temperatures because they soften, adhere in lumpy masses and clog screens.
The cooling is generated at the low temperature T L. Room temperature is T H . Figure 1 represents the Stirling-type single-orifice pulse-tube refrigerator (PTR), which is filled with a gas, typically helium at a pressure varying from 10 to 30 bar.
Cryogenic engineering is a sub stream of mechanical engineering dealing with cryogenics, and related very low temperature processes such as air liquefaction, cryogenic engines (for rocket propulsion), cryosurgery. Generally, temperatures below cold come under the purview of cryogenic engineering.