Views: 0 Author: J-VALVES Publish Time: 2025-02-23 Origin: Site
Design Standards for Low-Temperature LNG Gate Valves
This standard specifies the design, manufacturing, and testing requirements for low-temperature gate valves used in LNG applications. Key aspects include:
• Pressure and Temperature Ratings: Valves must be designed to withstand the specified pressures and temperatures, ensuring safe operation under extreme conditions.
• Valve Body and Bonnet: The valve body and bonnet must be made from materials that retain their strength and toughness at low temperatures.
• Valve Seat and Seals: The valve seat and seals must be made from materials that can maintain their sealing properties at cryogenic temperatures.
• Actuation and Control: The actuation mechanism must be designed to operate reliably at low temperatures, ensuring precise control.
Choosing the right materials is crucial for the performance and reliability of low-temperature LNG gate valves. Common materials include:
• Austenitic Stainless Steels: Grades such as 304L and 316L are often used due to their excellent low-temperature toughness and corrosion resistance.
• Duplex Stainless Steels: These materials offer a combination of strength and corrosion resistance, making them suitable for demanding applications.
• Nickel-Based Alloys: Alloys such as Inconel and Hastelloy provide superior strength and corrosion resistance at low temperatures.
• Cryogenic-Grade Plastics: For certain components, cryogenic-grade plastics like PTFE (Teflon) can be used for their low-temperature performance.
Low-temperature gate valves require precision machining to ensure tight tolerances and proper fit. This includes:
• Valve Seat and Disc: Precision machining ensures a tight seal, preventing LNG leakage.
• Valve Stem: The stem must be precisely machined to ensure smooth operation and prevent binding at low temperatures.
• Welding: Welding processes must be carefully controlled to ensure the integrity of the valve body and other components.
• Heat Treatment: Heat treatment is essential to relieve stresses and ensure the mechanical properties of the materials are maintained.
Valves must undergo rigorous pressure testing to ensure they can withstand the specified pressures at low temperatures.
Leak testing is crucial to verify the tightness of the valve seat and seals, ensuring no LNG leakage.
Valves must be tested at the specified low temperatures to ensure they maintain their performance and reliability.
Fire-safe testing ensures that the valve can withstand extreme temperatures and maintain its sealing integrity in case of a fire.
