Seals for Cryogenic Storage Tanks

Posted 2024-01-23 16:17:31

Seals used in cryogenic storage tanks are designed to withstand extremely low temperatures and maintain the integrity of the storage system for liquefied gases such as liquid nitrogen, liquid oxygen, and liquefied natural gas (LNG). These seals are crucial for preventing the escape of cryogenic liquids, minimizing heat ingress, and ensuring the safety and efficiency of the storage process. Here are key considerations for seals in cryogenic storage tanks:

Material Selection:
- Seals for cryogenic applications must be made from materials that remain flexible and resilient at extremely low temperatures. Common materials include elastomers like fluorocarbon (Viton), ethylene propylene diene monomer (EPDM), and polytetrafluoroethylene (PTFE).
Low-Temperature Flexibility:
- Cryogenic seals must maintain flexibility and elasticity at extremely low temperatures to ensure effective sealing. Special attention is given to the seal's ability to conform to irregularities and movements in the tank structure.
Vapor Tightness:
- Vapor tightness is critical in preventing the escape of cryogenic gases, which can be hazardous. Seals must provide an effective barrier to maintain the sealed environment within the storage tank.
Resistance to Cryogenic Fluids:
- Seals must resist degradation and swelling when exposed to cryogenic fluids. Compatibility with the specific cryogenic substance stored in the tank is essential to ensure long-term reliability.
Durability and Longevity:
- Cryogenic seals are subjected to extreme conditions, including temperature cycling and potential mechanical stresses during tank filling and emptying. Durable materials and designs are necessary to ensure the longevity of the seals and prevent failures.
Pressure Cycling:
- Cryogenic storage tanks often undergo pressure cycling as the stored liquids are filled and emptied. Seals must withstand these pressure variations without compromising their sealing performance.
Tank Lid Seals:
- Seals are used in various locations within cryogenic storage tanks, including on tank lids or hatches. These seals must effectively prevent the escape of cryogenic fluids when the tank is closed.
Flange Seals:
- Flange connections in cryogenic systems require seals that can handle low temperatures and maintain a reliable seal under the pressure and thermal cycling associated with cryogenic applications.
Safety Considerations:
- Seals play a critical role in ensuring the safety of cryogenic storage systems. Effective sealing helps prevent leaks that could lead to hazardous situations or compromise the integrity of the stored cryogenic substances.
Regulatory Compliance:
- Cryogenic storage systems are subject to stringent safety regulations and standards. Seals used in these applications must comply with relevant industry standards to ensure the overall safety and environmental responsibility of the storage facility.

In summary, seals for cryogenic storage tanks are specially designed to withstand the extreme conditions associated with low temperatures and the storage of cryogenic fluids. Material selection, flexibility, vapor tightness, durability, and safety considerations are crucial factors in designing and selecting seals for cryogenic applications.