Cryogenics

Cryogenics is often used incorrectly to refer to cryonics, cryopreserving humans or animals.

For the band, see Cryogenic (Band).

In physics or engineering, cryogenics is the study of the production of very low Kelvin scales.)

Definitions and distinctions

The terms cryogenics, cryobiology and cryonics are frequently confused. Other new terms with the prefix cryo- have also been introduced.

Cryogenics: The branches of physics and engineering that involve the study of very low temperatures, how to produce them, and how materials behave at those temperatures.

Cryobiology: The branch of biology involving the study of the effects of low temperatures on organisms (most often for the purpose of achieving cryopreservation).

Cryonics: The emerging medical technology of rheology, emergency medicine, etc.

superconductivity at low temperatures.

Cryotronics: The practical application of cryoelectronics.

Etymology

The word cryogenics literally means "the production of icy cold"; however the term is used today as a synonym for the low-temperature state. It is not well-defined at what point on the temperature scale hydrogen sulfide, and other common refrigerants have boiling points above -180 °C.

Industrial application

Liquefied gases, such as liquid nitrogen and liquid helium, are used in many cryogenic applications. Liquid nitrogen is the most commonly used element in cryogenics and is legally purchasable around the world. Liquid helium is also commonly used and allows for the lowest attainable temperatures to be reached.

These liquids are held in either special containers known as vacuum flasks fitted in a protective casing.

Cryogenic transfer pumps are the pumps used on LNG piers to transfer Liquefied Natural Gas from LNG Carriers to LNG storage tanks.

Cryogenic processing

The field of cryogenics advanced during World War II when scientists found that metals frozen to low temperatures showed more resistance to wear. Based on this theory of cryogenic processor in order to create more stable results.

Cryogens, like liquid brittle at very low temperatures, which makes cryogenic milling (grinding) an option for some materials that cannot easily be milled at higher temperatures.

Fuels

Another use of cryogenics is oxidizer of hydrogen, but oxygen is not, strictly speaking, a fuel.) For example, NASA's workhorse space shuttle uses cryogenic hydrogen fuel as its primary means of getting into orbit, as did all of the rockets built for the Soviet space program by Sergei Korolev. (This was a bone of contention between him and rival engine designer Valentin Glushko, who felt that cryogenic fuels were impractical for large-scale rockets such as the ill-fated N-1 rocket spacecraft.)

Russian aircraft manufacturer Tupolev is currently researching a version of its popular design Tu-154 with a cryogenic fuel system, known as the Tu-155. The plane uses a fuel referred to as liquefied natural gas or LNG, and made its first flight in 1989.

Production

Cryogenic cooling of devices and material is usually achieved via the use of liquid helium, or a cryocompressor (which uses high pressure helium lines).

Detectors

Cryogenic temperatures, usually well below 77 K (-196 °C) are required to operate cryogenic detectors.