Cryogenic valves, including cryogenic ball valve, cryogenic gate valve, cryogenic globe valve, cryogenic safety valve, cryogenic check valve, mainly used for three thousand tons ethene, liquefied natural gas and others that require temperature reached -196 degrees chemical equipments. Due to the output cryogenic liquid medium such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products are flammable and explosive, and also will gasify when rising temperature, when gasification, volume expansion hundreds of times. Cryogenic valves materials are very Important, If unqualified, will cause the shell and sealing surface external leakage or inner leakage, Parts of the mechanical properties, strength and stiffness can't satisfy the requirements and even rupture. Leading to liquefied natural gas medium leaking to explode.
Therefore, in the development, design, manufacture process of cryogenic valves, material handling Is the primary key problems...

Selection of cryogenic valve materials
1. Valve body and bonnet: LCB(-46℃), LC3(-101℃), Cf8(304) (-196℃);
2. Flashboard: Stainless steel welding cobalt cemented carbide;
3. Valve seat: Stainless steel welding cobalt cemented carbide;
4. Valve stem: 0Cr18Ni9.

Manufacturing and test of cryogenic valve
It has established strict manufacturing process and adopted special equipment for the production of cryogenic valve to rigorously control the quality of component processing. After special low-temperature treatment, it places rough machined component in cooling medium for hours (2-6 hours) to relieve, ensure low-temperature property of the materials and finish machining, avoid deformity and leakage of valve under low temperature due to temperature change. The assembly of valve is different from that of ordinary ones. The components should be strictly washed to remove oil and dirt and guarantee utilization property.

Test equipment of cryogenic valve
1. cryogenic valve test equipment;
2. Liquid nitrogen storage device;
3. Low-temperature treatment tank;
4. Low-temperature test bed guarantees the property of valve under low-temperature operating mode;
5. Others.

Test and inspection of cryogenic valve
Conduct low-temperature treatment for main components and parts of the low-temperature valve and sample each batch for low temperatureimpact test to ensure that the valve will not embrittle under low-temperature operating mode and resist against Impact from low-temperature medium.

Conduct test for each valve:
1. Room temperature shell strength test;
2. Room temperature low pressure upper seal test;
3. Room temperature low pressure seal test;
4. Low temperature upper seal air tight test (when there Is upper seal);
5. Low pressure air seal test ensures that the overall low-temperature valve meet standard;
6. Conduct low-temperature treatment for main components end parts of the low-temperature valve and
     sample each batch for low temperature impaettest to ensure that the valve will not embrittle under low-
     temperature operating mode and resist against Impact from low-temperature medium;
7. Low-temperature (copious cooling) valve adopts low-temperature treatment and impact test as per     relevant material standard;
8. Static electricity function is more powerful. The on-resistance between valve body and stem or internals     and valve body is less than lohm.

Extension Size For EB Type Ceyogenic Valve