Cryogenic Ball Valve

Cryogenic Ball Valve

Cryogenic ball valve

Cryogenic ball valve​ are mainly used in the chemical equipment of ethylene and LNG etc. to handle low temperature liquid medium like ethylene, liquid oxygen, liquid hydrogen and so on.

These types of inflammable and explosive medium can be volumetrically expanded by several hundred times when being gasified under temperature rise, and are difficult to manufacture due to their highly penetrative and leaky properties.

Product information

Structural properties

1. The materials of compression parts can endure the expansion and shrinkage resulted form the temperature variation of medium, and seal structure is away from permanent deformation under temperature changes. To work under the conditions below -100℃, the parts of valve shall be subject to deep cooling treatment before precision machining. Namely, have the parts cooled in liquid nitrogen box, when the temperature of parts reaches -196℃, keep the temperature for 1~2h, then take them out to have them to the normal temperature naturally, and do in this way twice.

2. Bonnet is extended for the purpose to protect the function of packing box, making packing box somewhat away from low temperature to ensure good seal of packing. Besides, it can be wound with cold insulating materials to prevent loss of cold energy. The length of neck depends on service temperature and the thickness of cold insulating material. When the effect of packing seal turns lower, fill in grease to form up oil seal layer from the middle of packing box, to lower the differntial pressure of packing box and enhance the reliability of seal.

3. To serve a temperature below -100℃, the material of valve stem shall be treated with chromeplating or nitriding to enhance the surface hardness of valve stem and the sealing reliability of packing.

4. Cryogenic ball valve takes a structure to avoid abnormal pressure rise. As the medium in cryogenic valve is gasified and rapidly expanded in volume, the pressure will goes extremely high. When the pressure in the middle cavity of valve rises, the middle cavity and the inlet side can be communicated, or a relief can be mounted at the inlet side of valve, thus to ensure the safe use of valves.

5. The gaskets used on cryogenic ball valves may function reliable seal and restoration under normal and low temperature or under the conditions of temperature changes.

Technical requirements

Applicable standards

Design codes: API 6D, ANSI B16.34, DIN 3357-1, EN 12516-1

Pressure/Temperature rating: ANSI B16.34

Structure length: API 6D, ASME B16.10, DIN 3202, GOST 3706

Flange ends: ASME B16.5, DIN 2542-2545, EN 1092, GOST 33259

Inspection and test: API 6D, API 598, DIN 3230/3, EN12266, GOST 9544

Type test of cryogenic ball valves

In accordance with the requirements of relative standards, the type test low temperature ball valves shall be carried out under both normal and low temperatures. With its principle as following:

Extension length of stem neck for low temp service(reference only)

Nominal sizeExtension lengthH(mm)Pressure
DNin≥-60℃≥-100℃<-100℃150Lb, 300LB, PN1.6-10.0MPa

Note: ★: stands for electrically operated valves;  △: stands for air operated valves;  ●: stands for handle operated valves.

Working temperature for different material

Standards, materials codeLowest tempStandards, materials codeLowest temp
ASTM A350 LF2-45.6℃ASTM A352 LCB, LCC-46℃
ASTM A350 LF5-59.4℃ASTM A352 LC1-59℃
ASTM A350 LF9-73.3℃ASTM A352 LC2-73℃
ASTM A350 LF3-101.1℃ASTM A352 LC3-101℃
ASTM A82 F304-254℃ASTM A351 CF8-254℃
ASTM A82 F316-254℃ASTM A351 CF8M-254℃
ASTM A82 F304L-254℃ASTM A351 CF3-254℃
ASTM A82 F316L-254℃ASTM A351 CF3M-254℃
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