Cryogenics

Source: Wikipedia, the free encyclopedia.
"Low temperature physics" redirects here. For the journal, see Low Temperature Physics (journal).
For cryopreservation of humans, see Cryonics. For the band, see Cryogenic (band).
Nitrogen is a liquid under −195.8 °C (77.3 K).
MIRI (Mid-Infrared Instrument) or James Webb Space Telescope
).
A medium-sized dewar is being filled with liquid nitrogen by a larger cryogenic storage tank.

In physics, cryogenics is the production and behaviour of materials at very low temperatures.

The 13th

air) lie below 120 K, while the Freon refrigerants, hydrocarbons, and other common refrigerants have boiling points above 120 K.[5][6]

Discovery of

superconducting materials with critical temperatures significantly above the boiling point of nitrogen has provided new interest in reliable, low cost methods of producing high temperature cryogenic refrigeration. The term "high temperature cryogenic" describes temperatures ranging from above the boiling point of liquid nitrogen, −195.79 °C (77.36 K; −320.42 °F), up to −50 °C (223 K; −58 °F).[7] The discovery of superconductive properties is first attributed to Heike Kamerlingh Onnes on July 10, 1908. The discovery came after the ability to reach a temperature of 2 K. These first superconductive properties were observed in mercury at a temperature of 4.2 K.[8]

Cryogenicists use the

Fahrenheit which measures from the freezing point of a particular brine solution at sea level.[11][12]

Definitions and distinctions

Cryogenics
The branches of engineering that involve the study of very low temperatures (ultra low temperature i.e. below 123 K), 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). Other applications include Lyophilization (freeze-drying) of pharmaceutical[13] components and medicine.
Cryoconservation of animal genetic resources
The conservation of genetic material with the intention of conserving a breed. The conservation of genetic material is not limited to non-humans. Many services provide genetic storage or the preservation of stem cells at birth. They may be used to study the generation of cell lines or for stem-cell therapy.[14]
Cryosurgery
The branch of surgery applying cryogenic temperatures to destroy and kill tissue, e.g. cancer cells. Commonly referred to as Cryoablation.[15]
Cryoelectronics
The study of electronic phenomena at cryogenic temperatures. Examples include superconductivity and variable-range hopping.
Cryonics
Cryopreserving humans and animals with the intention of future revival. "Cryogenics" is sometimes erroneously used to mean "Cryonics" in popular culture and the press.[16]

Etymology

The word cryogenics stems from Greek κρύος (cryos) – "cold" + γενής (genis) – "generating".

Cryogenic fluids

Cryogenic fluids with their boiling point in Kelvin[17] and degree Celsius.

Fluid Boiling point (K) Boiling point (°C)
Helium-3 3.19 -269.96
Helium-4 4.214 -268.936
Hydrogen 20.27 -252.88
Neon 27.09 -246.06
Nitrogen 77.09 -196.06
Air 78.8 -194.35
Fluorine 85.24 -187.91
Argon 87.24 -185.91
Oxygen 90.18 -182.97
Methane 111.7 -161.45

Industrial applications

Catalogue image of a cryogenic valve
Cryogenic valves in situ, with condensed atmospheric humidity
Further information: Low-temperature technology timeline

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 may be stored in

Thermos bottles are smaller vacuum flasks
fitted in a protective casing.

Cryogenic barcode labels are used to mark Dewar flasks containing these liquids, and will not frost over down to −195 degrees Celsius.[18]

Cryogenic transfer pumps are the pumps used on

LNG piers to transfer liquefied natural gas from LNG carriers to LNG storage tanks
, as are cryogenic valves.

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 tempering instead of heat treating.[citation needed
] This evolved in the late 1990s into the treatment of other parts.

Cryogens, such as liquid

cryomilling
) an option for some materials that cannot easily be milled at higher temperatures.

Cryogenic processing is not a substitute for heat treatment, but rather an extension of the heating–quenching–tempering cycle. Normally, when an item is quenched, the final temperature is ambient. The only reason for this is that most heat treaters do not have cooling equipment. There is nothing metallurgically significant about ambient temperature. The cryogenic process continues this action from ambient temperature down to −320 °F (140 °R; 78 K; −196 °C). In most instances the cryogenic cycle is followed by a heat tempering procedure. As all alloys do not have the same chemical constituents, the tempering procedure varies according to the material's chemical composition, thermal history and/or a tool's particular service application.

The entire process takes 3–4 days.

Fuels

Another use of cryogenics is

oxidizer, not a fuel. NASA's workhorse Space Shuttle used cryogenic hydrogen/oxygen propellant as its primary means of getting into orbit. LOX is also widely used with RP-1 kerosene, a non-cryogenic hydrocarbon, such as in the rockets built for the Soviet space program by Sergei Korolev
.

Russian aircraft manufacturer

Tu-155. The plane uses a fuel referred to as liquefied natural gas or LNG, and made its first flight in 1989.[20]

Other applications

Astronomical instruments on the Very Large Telescope are equipped with continuous-flow cooling systems.[21]

Some applications of cryogenics:

  • spectrometers
    that do not require cryogens. In traditional superconducting solenoids, liquid helium is used to cool the inner coils because it has a boiling point of around 4 K at ambient pressure. Cheap metallic superconductors can be used for the coil wiring. So-called high-temperature superconducting compounds can be made to super conduct with the use of liquid nitrogen, which boils at around 77 K.
  • Magnetic resonance imaging (MRI) is a complex application of NMR where the geometry of the resonances is deconvoluted and used to image objects by detecting the relaxation of protons that have been perturbed by a radio-frequency pulse in the strong magnetic field. This is most commonly used in health applications.
  • In large cities, it is difficult to transmit power by overhead cables, so underground cables are used. But underground cables get heated and the resistance of the wire increases, leading to waste of power. Superconductors could be used to increase power throughput, although they would require cryogenic liquids such as nitrogen or helium to cool special alloy-containing cables to increase power transmission. Several feasibility studies have been performed and the field is the subject of an agreement within the International Energy Agency.
Cryogenic gases delivery truck at a supermarket, Ypsilanti, Michigan
  • Cryogenic gases are used in transportation and storage of large masses of frozen food. When very large quantities of food must be transported to regions like war zones, earthquake hit regions, etc., they must be stored for a long time, so cryogenic food freezing is used. Cryogenic food freezing is also helpful for large scale food processing industries.
  • Many infrared (
    forward looking infrared
    ) cameras require their detectors to be cryogenically cooled.
  • Certain rare blood groups are stored at low temperatures, such as −165 °C, at blood banks.
  • Cryogenics technology using liquid nitrogen and CO2 has been built into nightclub effect systems to create a chilling effect and white fog that can be illuminated with colored lights.
  • Cryogenic cooling is used to cool the tool tip at the time of machining in
    manufacturing process
    . It increases the tool life. Oxygen is used to perform several important functions in the steel manufacturing process.
  • Many rockets and lunar landers use cryogenic gases as propellants. These include liquid oxygen, liquid hydrogen, and liquid methane.
  • By freezing the automobile or truck tire in liquid nitrogen, the rubber is made brittle and can be crushed into small particles. These particles can be used again for other items.
  • Experimental research on certain physics phenomena, such as spintronics and magnetotransport properties, requires cryogenic temperatures for the effects to be observed.
  • Certain vaccines must be stored at cryogenic temperatures. For example, the Pfizer–BioNTech COVID-19 vaccine must be stored at temperatures of −90 to −60 °C (−130 to −76 °F). (See cold chain.)[22]

Production

Cryogenic cooling of devices and material is usually achieved via the use of liquid nitrogen, liquid helium, or a mechanical cryocooler (which uses high-pressure helium lines). Gifford-McMahon cryocoolers, pulse tube cryocoolers and Stirling cryocoolers are in wide use with selection based on required base temperature and cooling capacity. The most recent development in cryogenics is the use of magnets as regenerators as well as refrigerators. These devices work on the principle known as the magnetocaloric effect.

Detectors

There are various

cryogenic detectors
which are used to detect particles.

For cryogenic temperature measurement down to 30 K, Pt100 sensors, a resistance temperature detector (RTD), are used. For temperatures lower than 30 K, it is necessary to use a silicon diode for accuracy.

See also

References

  1. ^ International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.php Archived 2019-10-01 at the Wayback Machine
  2. ^ ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology
  3. ^ "Cryogenics is usually defined as the science and technology dealing with temperatures less than about 120 K [4,5], although this review does not adhere to a strict 120 K definition." K.D. Timmerhaus, R. Reed. Cryogenic Engineering: Fifty Years of Progress. Springer Science+Business Media LLC (2007), chapter: 1.2 The Beginning of Cryogenics, p. 7
  4. ^ "About Cryogenics". In terms of the Kelvin scale the cryogenic region is often considered to be that below approximately 120 K (-153 C).
  5. ^ "DICHLORODIFLUOROMETHANE at Pubchem".
  6. ^ "PROPANE at Pubchem".
  7. ^ J. M. Nash, 1991, "Vortex Expansion Devices for High Temperature Cryogenics", Proc. of the 26th Intersociety Energy Conversion Engineering Conference, Vol. 4, pp. 521–525.
  8. ISBN 978-0-387-46896-9
  9. ^ Celsius, Anders (1742) "Observationer om twänne beständiga grader på en thermometer" (Observations about two stable degrees on a thermometer), Kungliga Svenska Vetenskapsakademiens Handlingar (Proceedings of the Royal Swedish Academy of Sciences), 3: 171–180 and Fig. 1.
  10. Facts On File, Manhattan
    , New York City. p. 43.
  11. ^ Fahrenheit temperature scale, Encyclopædia Britannica Online. 25 September 2015
  12. ^ "Fahrenheit: Facts, History & Conversion Formulas". Live Science. Retrieved 2018-02-09.
  13. ^ Evans, Nicole. "What is Cryobiology?". www.societyforcryobiology.org. Retrieved 2023-11-27.
  14. PMID 21566712
    .
  15. ^ "Cryosurgery to Treat Cancer". NCI. June 21, 2021. Retrieved 2023-11-27.
  16. ^ "Cryonics is NOT the Same as Cryogenics". Cryogenic Society of America. Archived from the original on 2 December 2018. Retrieved 5 March 2013.
  17. McGraw-Hill Book Company
    .
  18. ^ Thermal, Timmy. "Cryogenic Labels". MidcomData. Retrieved 11 August 2014.
  19. ISBN 978-0-7864-7687-9
    .
  20. ^ "Tu-155 / Tu-156". www.globalsecurity.org. Retrieved 2023-11-27.
  21. ^ "ESO Signs Technology Transfer Licence Agreement for Cooling System". Retrieved 11 June 2015.
  22. ^ "Pfizer–BioNTech COVID-19 Vaccine Vaccination Storage & Dry Ice Safety Handling". Pfizer-BioNTech. Archived from the original on 24 January 2021. Retrieved 17 December 2020.

Further reading

  • Haselden, G. G. (1971), Cryogenic fundamentals, Academic Press, New York,
    ISBN 0-12-330550-0
    .
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