Cryogenic Service Forward-Acting Rupture Disc
Product Model: ZD-013 (Cryogenic Grade)
Material: Specially treated 304L or 316L stainless steel, or Nickel alloys.
Temperature Range: Certified for service down to -196°C (Liquid Nitrogen temperature) and lower.
Key Feature: Materials retain ductility and specified burst pressure at extreme cryogenic temperatures.
Design: Consideration for thermal contraction and seal integrity.
Typical Use: LNG storage & processing, liquid oxygen/nitrogen/argon tanks, cryogenic reactors, and space simulation chambers.
Overview
Protecting equipment containing liquefied gases requires a rupture disc that will function reliably not just at ambient conditions, but at the extremely low temperatures of the process fluid. Standard discs can become brittle and their burst pressure can shift. Our cryogenic-grade forward-acting disc uses materials and manufacturing processes verified to maintain ductility and accurate burst performance deep into the cryogenic range, ensuring safety for LNG terminals, air separation plants, and specialty chemical processes.
Features & Benefits
Certified Low-Temperature Performance: Materials are Charpy impact tested to guarantee toughness at the specified minimum temperature.
Stable Burst Pressure: The disc's burst pressure rating is characterized and guaranteed at the cryogenic service temperature, not just at room temperature.
Leak-Tight Seals: Gasket or seal materials (e.g., specially formulated PTFE, metal O-rings) are selected for compatibility and sealing performance at low temperatures.
Thermal Stress Management: Design accounts for differential contraction between parts to prevent leakage or distortion during cooldown.
How It Works
The fundamental tensile rupture mechanism remains the same. However, the material's mechanical properties (yield strength, ductility) at cryogenic temperatures are the critical design parameters. The disc is engineered so that at the operating temperature, it will rupture accurately at its rated pressure without brittle fracture.
Specifications (Descriptive)
Standard sizes from DN50 to DN300 for typical tank nozzle installations. Burst pressures are often low to medium for storage applications (e.g., 0.5 to 4 barg for an LNG tank vent). Common materials are 316L SS for general cryogenics or Nickel 200 for superior low-temp ductility. Each disc for critical service is supplied with a material test certificate showing compliance with low-temperature impact standards (e.g., ASTM A20). Holders may be made from similar low-temp materials.
Q&A
Q: Why can't I use a standard rupture disc for LNG?
A: Standard discs may use materials or heat treatments that cause embrittlement at very low temperatures. This could lead to premature failure (leakage) or an unpredictable burst pressure, creating a major safety hazard.
Q: How do you test burst pressure at cryogenic temperatures?
A: While 100% testing at cryogenic temperatures is impractical, the discs are manufactured from lots of material rigorously tested for low-temperature properties. The design is validated through analysis and sample testing at temperature. The burst pressure rating is derated or specifically calculated for the cold condition.
Q: What about insulation on the disc?
A: The disc assembly should be installed so it is in thermal contact with the cold process to ensure its temperature is accurate. External insulation on the holder is common to prevent frost formation and personal injury, but should not heat the disc itself.
About ZD Safety
Safety has no temperature limit. Our expertise in low-temperature materials ensures that your cryogenic assets, from laboratory dewars to large-scale LNG facilities, are protected with reliable, performance-guaranteed safety devices.
