Stainless Steel Cryogenic Gate Valve SS316 3 Inch 600LB Extended Bonnet Flanged

Product Specification

Stainless Steel Cryogenic Gate Valve 3" 600LB LNG Service

Product Introduction

This stainless steel cryogenic gate valve is specifically designed for liquefied natural gas (LNG), liquid nitrogen (LIN), liquid oxygen (LOX), liquid argon (LAR), and other cryogenic industrial gas applications. The ASTM A351 CF8M (SS316) investment cast body provides excellent low-temperature toughness and corrosion resistance. The extended bonnet design positions the stuffing box and actuator away from the cold process fluid, preventing packing freeze-up and ensuring reliable operation at temperatures as low as -196°C. Every valve undergoes mandatory cryogenic seat leakage testing in liquid nitrogen per BS 6364 to verify bubble-tight shutoff at cryogenic temperatures.

Key Features & Characteristics

• Extended Bonnet Cryogenic Design: The extended bonnet column creates a thermal barrier between the cryogenic process fluid and the packing/stem seal area, allowing the packing to operate at near-ambient temperatures and preventing ice formation on the stem. Bonnet extension length is calculated per BS 6364 based on insulation thickness and cold box configuration.
• CF8M Stainless Steel Construction: Type 316 austenitic stainless steel maintains excellent impact toughness at cryogenic temperatures (Charpy V-notch > 27J at -196°C) and provides superior corrosion resistance for marine, coastal, and chemical processing environments.
• Flexible Wedge Gate with Stellite Seats: The flexible solid wedge gate compensates for minor body distortions caused by thermal contraction while the Stellite 6 hardfaced seats maintain sealing integrity through repeated thermal cycles from ambient to cryogenic temperatures.
• Vented Gate Cavity: A pressure relief hole in the upstream side of the gate prevents cavity over-pressurization as trapped liquid gasifies during warm-up, eliminating the risk of body rupture.
• Anti-Blowout Stem: The stem incorporates an integral shoulder that prevents ejection under packing failure conditions, meeting API 600 anti-blowout requirements.
• Clean Room Assembly: All cryogenic valves are assembled in a controlled clean environment with hydrocarbon-free lubricants suitable for oxygen service when specified.

Why Choose Us

• Cryogenic Testing as Standard: Every cryogenic valve undergoes mandatory seat leakage and operational testing submerged in liquid nitrogen (-196°C) per BS 6364, with test certificates and charts provided in the documentation package.
• Oxygen Clean Service Capability: Valves can be supplied cleaned, degreased, and bagged for oxygen service per CGA G-4.1 and ASTM G93 standards, with certification of cleanliness provided.
• Full Cryogenic Service Line: We offer a complete range of cryogenic gate, globe, check, and ball valves from 1/2" to 24" in pressure classes 150LB through 2500LB for comprehensive LNG terminal and air separation unit packages.
• Global LNG Project Experience: Our cryogenic valves are installed in LNG receiving terminals, peak-shaving plants, and air separation units across Southeast Asia, Middle East, and Africa.
• After-Sales Support: Technical service team available for cold box installation supervision and on-site cryogenic performance verification.

Technical Parameter Table

FAQ

Q: Why is an extended bonnet necessary for cryogenic valves?
A: In cryogenic service, the extreme cold (-162°C for LNG, -196°C for LIN) can freeze the valve packing, causing stem seizure and packing leakage. The extended bonnet creates a thermal column where the gas inside acts as an insulator, keeping the packing area warm enough to function properly. Without an extended bonnet, the valve would quickly fail in cryogenic service.

Q: Can these valves be used for liquid oxygen (LOX) service?
A: Yes, when specified for oxygen service, we provide special cleaning to remove all hydrocarbons, use oxygen-compatible lubricants and packing materials, and package in sealed bags marked "Cleaned for Oxygen Service" per CGA G-4.1. Oxygen service certification is provided with each valve.

Q: What is the delivery time for custom cold box extension lengths?
A: Standard 600mm bonnet extensions are available from stock. Custom extension lengths (up to 3000mm) require 25-35 working days depending on the stem material availability and machining requirements.