The ultimate guide to choosing cryogenic valves |
The ultimate guide to choosing cryogenic valves
Knowing the types of cryogenic valves available and their technical specifications is essential in order to choose the right one for your needs.
How do they work: Cryogenic Valves
Cryogenic valves operate at temperatures below -40°C and are primarily used for gas liquefaction. In separation, transport, and storage equipment, their operating temperature can dip below -270°C.
These valves are naturally kept in a closed position to contain gases or other materials. They react to high pressure to open and allow flow but will close when the pressure decreases, sealing with a special metal-seated hermetic seal to prevent leakage.
Choosing the right cryogenic valves
Cryogenic valves are becoming more prominent in industrial sectors like petrochemical or natural gas. They are used with low-temperature working materials that are toxic, flammable, or explosive. To ensure safe usage, they must meet several special requirements.
These features include higher packing sections and an extended stem to reduce heat transfer into the device.
Another crucial factor is the design of the long-neck bonnet. This design aspect takes into account thermal conductivity, surface heat dissipation, and other parameters calculated through experimental methods.
Regarding materials, manufacturers must ensure that the device body can withstand temperature changes and the resulting expansion or contraction movements. This should avoid any deformation. For instance, ferritic stainless steel is suitable when the temperature is above -100°C, while austenitic stainless steel is used for temperatures below -100°C. On the other hand, copper or aluminum alloys are preferred for small diameter, low pressure valves.
Cryogenic valves: types and differences
Various shapes and sizes of cryogenic valves are available today, suitable for different pressure ranges. Common ones include ball, butterfly, relief, and solenoid valves. They can be manual or automatic, which is essential in large systems.
Cryogenic ball valves have a polytetrafluoroethylene body, providing better flow rates than globe valves. However, these valves can wear easily around the seals and the ball itself, making them more suited for systems with unrestricted flow paths.
Cryogenic relief valves prevent overpressure above a certain value by allowing steam to escape if safety limits are exceeded. Similarly, cryogenic non-return valves maintain pressure and prevent fluid backflow.
Cryogenic globe valves feature a spherical shape and an internal moving disc that rotates at a 90-degree angle relative to its body mounting, offering effective long-term sealing but not suitable for high-flow systems.
A cryogenic gate valve has a wedge-shaped gate that closes in line with the body mounting for minimal pressure drop even when fully open.
Cryogenic butterfly valves have a circular disc in the center, making them lighter and more economical. They are best for systems that require rapid opening and closing actions.
Always remember, cryogenic gases are very sensitive and leaks can pose significant risks. A cryogenic safety valve is vital for ensuring the system functions correctly.
In summary, cryogenic valves are essential for installations involving cryogenic liquids to guarantee safety and proper handling.
Keep reading: Cryogenic Industrial Solutions that every cryogenic company should offer
If you are in need of any cryogenic solution like cryogenic valves, Cryospain is your go-to! We offer cryogenic engineering tailored to the needs of each project since our inception in 2002. Contact us and let us know about your project.
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