Cryogenic valves are mainly used in ethylene, liquefied natural gas equipment, air separation equipment, petrochemical tail gas separation equipment, liquid oxygen, liquid nitrogen, liquid argon, carbon dioxide cryogenic storage tanks and tankers, pressure swing adsorption oxygen production and other equipment, the main varieties are cryogenic ball valves, cryogenic globe valves, etc.
The cryogenic valve is suitable for temperatures from -46 °C --- 196 °C, and even cryogenic -273 degrees. The medium is through the liquefied gas, with the characteristics of volume expansion when heating, so the requirements for the raw materials of the valve body are very high, once there are unqualified products, it is possible to form a vicious accident of valve body bursting. The upper bonnet sealing packing of the cryogenic control valve will freeze in the case of low temperature, and when the switch is constantly opened, the iced packing will be torn apart and form an external leakage, so the upper valve cover needs to be heightened, so that the low-temperature medium has been heated by the surrounding air when it arrives at the stuffing box, and will not be frozen, so as to eliminate leakage.
The raw material selected for cryogenic valves is mainly 304 stainless steel, (at -20-46 °C, LCB low-temperature carbon steel can be selected to reduce the cost of use), and the packing is mainly PTFE, because PTFE has excellent anti-cold flow characteristics, so it is widely used in cryogenic valves. Cryogenic control valve, the first of all, pneumatic cryogenic control valve and electric cryogenic control valve, in the factory liquid nitrogen application system, as well as the air separation system is widely used, with simple use, high control accuracy, long service life and other characteristics, the factory is required to pass the low temperature test, to meet the requirements of the site of the application conditions.
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