How to Define Low Temperature Valve?

How to Define Low Temperature Valve?


With the rapid development of modern science and technology in recent decades, there is an increasing demand for cryogenic valves in engineering projects. Cryogenic valves are used in many fields such as chemical fertilizers, LNG, and petrochemicals. 

 In addition to liquid nitrogen and other liquid inert gases, most of the media controlled by cryogenic valves are not only flammable and explosive, but also vaporize when they are heated or flashed. As a result, the volume rapidly expands, which can easily lead to leakage and explosion.

Based on the characteristics of the medium and the requirements for adapting the valve to use at low temperatures, the design, manufacture, testing and installation methods of the cryogenic valve are different from ordinary valves. The standards and definitions of Cryogenic valve. Different standards have different definitions for cryogenic valves. 

According to British valve standard BS6364 "valve for low temperature" is suitable for medium temperature range -50°C~-196°C.

According to American Standard MSSSP-134 "The requirement for cryogenic valves and their body/bonnet extensions" interprets low temperatures as "for standard practices, the low temperature range is -100°C to -195°C." 

According to Chinese National Standard GB/T 24925, "Cryogenic valve technical conditions" standard applies to medium temperature range -29 °C ~ -196 °C;

According to SHELL MESC SPE 77/200, Valves for low and low temperatures" is suitable for medium temperature range -30 °C ~ -196 °C.
According to various foreign gases, the liquefaction temperature under normal pressure is generally divided into six temperature levels.

LEVELⅠ 0~ -46℃
LEVEL Ⅱ -47~ -60℃
LEVELⅢ -61~ -70℃
LEVELⅣ -71~-101℃
LEVELⅤ -102~-196℃ 
LEVELⅥ  below -253℃

Generally -46~-150°C is called low temperature, and the temperature bellow -150℃ is called ultra-low temperature. The definition of cryogenic valves in the petrochemical industry is defined in terms of the design temperature of the transmission medium. Generally, valves with a temperature below -40 °C are referred to as cryogenic valves. Valves with a temperature below -101 °C are referred to as ultra-low temperature.
 
How to Define Low Temperature Valve?



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