LNG Methane Resistant PTFE Spring Energized Seal Ring & O Ring Gasket

1. Product Overview

LNG seal rings are professional cryogenic sealing components specially designed for extreme low-temperature, medium-high pressure, and flammable & explosive LNG working conditions. They are core parts to ensure zero leakage and safe operation of LNG storage, transportation, and filling equipment.

These seals feature excellent ultra-low temperature resistance, low shrinkage, methane permeation resistance, and flame retardant & explosion-proof performance. They can stably adapt to the boiling point environment of liquefied natural gas at -162°C, and are widely used in LNG valves, filling guns, pumps, pipeline flanges and other key equipment.

2. Core Working Condition Parameters

• Working Temperature: Permanent operating temperature -162°C; short-term extreme temperature up to -196°C (liquid nitrogen environment)

• Working Pressure: Static pressure 1.0–10MPa; dynamic working pressure (filling gun & pump) 3.0–3.5MPa

• Applicable Media: Liquid/gaseous methane, ethane, propane and other natural gas components

• Core Performance Standards: No brittle cracking at ultra-low temperature, shrinkage rate ≤0.5%, low methane swelling rate, excellent flame retardancy, and high sealing tightness

• Leakage Standard: Helium leak detection rate ≤1×10⁻⁹Pa·m³/s, realizing zero leakage

3. Main Material Classification & Performance

3.1 Non-metallic Sealing Materials (Sealing Core)

• Modified PTFE: The most mainstream cryogenic sealing material. Resistant to -196°C ultra-low temperature, chemically inert, low friction coefficient. Optimized by glass fiber/carbon fiber modification to effectively avoid cold flow deformation, matching with spring energy storage structure for stable dynamic and static sealing.

• Cryo-PEEK: High-end ultra-low temperature resistant material. Super high toughness and pressure resistance (≤70MPa) at -196°C, extremely low gas permeability. Ideal for high-pressure LNG ball valve seat sealing, with long service life, suitable for harsh working conditions.

• Flexible Graphite: Maintains good flexibility at -200°C, with excellent flame retardant, high temperature resistance and corrosion resistance. Matched with metal skeleton for flange gaskets and packing sealing.

• AFLAS & Modified HNBR: Professional cryogenic elastomer. AFLAS adapts to -160°C–200°C, resistant to methane swelling; modified HNBR features outstanding wear resistance, suitable for low-pressure static sealing of LNG equipment.

3.2 Metal Reinforced Materials (Skeleton & Spring)

• 316L Mod Stainless Steel: Used for metal winding gasket skeleton and sealing flange connection, with excellent low-temperature corrosion resistance and structural stability.

• Elgiloy (Cobalt-Chromium-Nickel Alloy): Special spring material for energy storage seals. No phase change at -196°C, stable elastic force, anti-fatigue and long service life.

• Stellite (Cobalt-Chromium-Tungsten Alloy): Surfacing material for valve seats, effectively improving scouring resistance and wear resistance of sealing surface.

4. Main Product Types & Applications

4.1 Spring Energy Storage Seal Ring (Core Dynamic Seal)

Structure: Modified PTFE/UHMWPE sealing sleeve + Elgiloy alloy energy storage spring

Performance: Adaptable to -196°C–80°C, pressure resistance up to 3.45MPa

Application: LNG filling guns, cryogenic liquid pumps, valve dynamic sealing parts, compatible with Chart, Furui, Huaqi Houpu and other mainstream equipment brands.

4.2 Metal Spiral Wound Gasket (Flange Static Seal)

Structure: 316L Mod steel strip + flexible graphite filler, with inner and outer positioning rings

Performance: Temperature resistance -196°C–450°C, maximum pressure resistance 25MPa

Application: Static sealing of LNG storage tanks, process pipelines, unloading arm flange connections.

4.3 Cryogenic Rubber O-Ring (Conventional Static Seal)

Material: AFLAS / modified HNBR, hardness Shore A 70–90

Performance: Excellent low-temperature elasticity and methane corrosion resistance

Application: Static sealing of equipment end covers, manholes and low-pressure flanges (working pressure ≤5MPa, temperature ≥-100°C).

5. Industry Certification & Testing Standards

• API 6D: International standard for LNG valve sealing, realizing zero leakage under ultra-low temperature working conditions

• ISO 16010: Global standard for gas pipeline sealing components, compliant with hydrocarbon medium resistance and low-temperature toughness requirements

• Shell MESC SPE 77/302: Professional certification for Cryo-PEEK cryogenic sealing components

• Professional Testing Items: Ultra-low temperature (-196°C) impact test, methane swelling test, permanent compression deformation test, helium tightness test

6. Common Failure Causes & Selection Guidelines

6.1 Common Failure Reasons

• Ordinary rubber materials are prone to elasticity loss and brittle fracture below -50°C

• Pure PTFE without modification suffers from cold flow deformation and long-term leakage under high pressure

• Conventional NBR materials have high methane swelling rate and are not applicable to LNG medium

• Ordinary stainless steel springs undergo low-temperature phase change and elastic attenuation

6.2 Professional Selection Guide

• Dynamic Sealing (Filling Gun/Pump): Prefer Elgiloy spring + modified PTFE energy storage seal ring

• Pipeline Flange Static Sealing: Select 316L Mod + flexible graphite spiral wound gasket

• Ball Valve Seat Sealing: High-pressure working condition for Cryo-PEEK seal; low-pressure working condition for modified PTFE spring seal

• Medium & Low Temperature Static Sealing: Cost-effective AFLAS cryogenic O-ring

7. Product Advantages

• Ultra-low Temperature Resistance: No cracking or deformation at -196°C, stable sealing performance

• Medium Resistance: Resistant to methane and natural gas corrosion, low swelling and no aging

• High Sealing Precision: Strict helium leakage test, zero leakage for long-term operation

• Durable & Anti-fatigue: Imported alloy spring, stable elasticity, long service life

• Full Specification Coverage: Complete models, customizable for various LNG equipment