The low temperature cryogenic treatment flange butterfly valve is a quarter-turn isolation valve engineered for sub-zero and cryogenic service on liquefied gas, cold ethylene and refrigerated hydrocarbon circuits where conventional resilient-seated designs lose elasticity and fail to maintain bubble-tight shut-off. Manufactured by Trekre Valve at our Wuxi production facility, this double-flanged triple offset butterfly valve combines deep-cryogenic material treatment, metal hard sealing and worm gear manual operation for the specified cold-service isolation duty on lines handling media that expand dramatically when warmed above their boiling point.
Cryogenic flange butterfly valves differ from standard HVAC or water-service butterfly valves in three critical respects: body and trim materials must retain impact toughness at −40 °C and below; stem and seat seals must remain flexible without taking a compression set at cold temperature; and the triple offset disc geometry must achieve metal-to-metal closure without the seat scrubbing that would gall stainless pairs in the absence of adequate lubricating film. Trekre applies controlled low-temperature cryogenic treatment to selected cast and forged components, stabilizing metallurgical structure and reducing residual stress before final machining and assembly.
Low temperature cryogenic treatment flange butterfly valve construction
Connection type: double-flanged (raised face or flat face per ANSI, DIN, EN or JIS specification)
Structure: triple offset (triple eccentric) butterfly valve with metal hard seal
Size range: 2″ to 48″ (DN50 to DN1200); larger diameters on engineering review
Pressure rating: ANSI Class 150 / 300; EN PN16 / PN25 / PN40; JIS 10K / 20K (size and standard dependent)
Body material: low-temperature carbon steel LCB / LCC, stainless steel CF8 / CF8M, or cryogenic-grade alloy per media compatibility review
Disc material: stainless steel with Stellite or hard-facing on the sealing edge; cryogenic-treated stem and hub assemblies
Seat material: metal hard seal; laminated stainless / PTFE composite or graphite laminate optional for specific cold cycling duty
Operation: worm gear manual with handwheel (standard); chain wheel, electric multi-turn or pneumatic actuator optional
Design standards: API 609, EN 593, MSS SP-67, BS 6364 for low-temperature valve applications (project specified)
Working temperature: the qualified minimum and maximum design temperatures of the actual valve assembly (material, packing and actuator selection dependent)
Leakage class: bubble-tight metal seat per API 598 / EN 12266 within rated cold-temperature envelope
Why cryogenic treatment matters on flange butterfly valves
Standard cast steel butterfly valve bodies may appear dimensionally correct at room temperature yet exhibit reduced Charpy impact values when the line drops to −40 °C, −101 °C (ethylene) or −162 °C (LNG boiling point at near-atmospheric pressure). A sudden thermal transient during depressurization, emergency venting or failed insulation can drive body and bonnet temperatures below the ductile-to-brittle transition range of untreated carbon steel. Cryogenic material selection—LCB/LCC bodies, austenitic stainless trim and controlled deep-cooling treatment of critical rotating parts—addresses this failure mode before the valve is bolted between flanges on an LNG vaporizer outlet or ethylene refrigeration loop.
Liquid oxygen, liquid hydrogen, ethylene and LNG share a common hazard profile: they are cold, often flammable or strongly oxidizing, and they vaporize rapidly when ambient heat ingress exceeds removal capacity. Volume expansion from liquid to gas can exceed six hundred to one thousand times, pressurizing confined spaces if isolation valves leak or fail to close. Specifying a triple offset metal hard seal flange butterfly valve with proven cold-temperature test history reduces the probability of seat leakage that would allow warm-up and over-pressurization upstream of a closed valve.
Flanged end connections remain the preferred format on cryogenic headers because spool pieces can be prefabricated, leak-tested and insulated in the shop before field assembly. Double-flange butterfly valves bolt between companion flanges with gaskets rated for cold service—PTFE, graphite laminate or spiral-wound stainless with PTFE filler—while the valve body profile accepts vacuum-insulated jacketing or multi-layer cryogenic insulation without interfering with wafer-style through-bolting limitations.
Triple offset sealing at cold temperature
Triple eccentric geometry lifts the disc off the metal seat before rotation begins, minimizing the sliding friction that would otherwise generate heat and galling between stainless sealing pairs in dry cryogenic service. On the final closing degrees, the disc follows a conical cam path into the seat ring, producing line-contact closure rather than the full-face shear typical of concentric resilient-seated valves. This mechanism maintains repeatable shut-off after thousands of cycles on cold ethylene transfer lines and LNG loading arms where operators expect the same handwheel rim pull at −101 °C as at ambient commissioning temperature.
Metal hard sealing extends the operating window below the practical limit of EPDM, NBR or PTFE envelope seats, which stiffen and lose recovery as temperature falls. While fully lined soft-seat butterfly valves suit chilled water, they are generally excluded from LNG and liquid ethylene block-valve duty because seat elastomers cannot guarantee bubble-tight performance across the full cold envelope. The Trekre cryogenic flange series therefore targets applications where metal seat integrity and fire-safe behavior are part of the process hazard analysis.
Typical applications and industry sectors
LNG terminals and regasification: send-out line isolation, vaporizer inlet/outlet block valves, boil-off gas header control
Ethylene and olefin plants: refrigeration compressor suction and discharge isolation, cold box transfer headers
Air separation units: liquid oxygen and liquid nitrogen storage ring main isolation (material compatibility review mandatory for LOX service)
Petrochemical cold storage: LPG and refrigerated ammonia transfer, dock loading arm root valves
Industrial gas distribution: bulk tank farm isolation on liquid CO₂ and cold hydrocarbon service
Power and combined cycle: fuel gas conditioning trains handling cold separation products downstream of cryogenic recovery
Worm gear operation and actuator options
Worm gear manual operators with handwheel are standard on cryogenic flange butterfly valves from 6″ upward, converting manageable rim pull into the seating torque required by triple offset metal discs under differential pressure across the closed element. Gear housings are sized for breakaway torque at cold temperature when grease viscosity increases and stem packing friction rises. Optional chain wheel extensions allow floor-level operation on valves mounted at height inside insulated pipe racks, eliminating the need for personnel to reach cold surfaces during routine switching.
Electric multi-turn actuators suit remote isolation on LNG utility headers linked to plant DCS or ESD systems. Pneumatic double-acting actuators provide faster stroke for emergency shutdown sequences. Trekre selects each actuator after calculating breakaway, running and seated torque at the specified cold temperature and differential pressure, including safety margins for degraded packing condition after extended service. ISO 5211 mounting interfaces on the valve top flange accept standardized actuator adapters without field modification.
Material selection and cryogenic compatibility
LCB and LCC low-temperature carbon steel bodies require grade-specific verification against the actual minimum design temperature and cannot be assumed suitable for LNG liquid service within ASME B16.34 impact-tested temperature ratings. CF8M stainless bodies and trim are specified when the line carries traces of moisture that could form corrosive films, or when client specifications mandate austenitic internals throughout. For liquid oxygen service, copper-free construction and specialized cleaning procedures are required; each project receives a separate material compatibility review because oxidizing cryogens impose stricter contamination limits than hydrocarbon cold service.
Stem packing systems combine PTFE or graphite live-loaded rings with anti-blowout stem retention. Bonnet extensions and stem lengthening options position packing above the cold zone and outside the insulation envelope, keeping the seal area at a temperature where elastomer or graphite packing remains compliant. Cryogenic treatment of the stem, disc hub and key fasteners reduces distortion during rapid cooldown events when the valve transitions from ambient storage to operating cold.
Installation, insulation and testing requirements
Install cryogenic flange butterfly valves with stem vertical or horizontal per manufacturer guidance; avoid orientations that would trap condensate against the packing chamber. Flange gaskets must match the cryogenic media and design temperature—compressed PTFE, spiral-wound stainless with PTFE filler or approved graphite laminate types are common selections. Torque flange bolts in a star pattern to the specification for the gasket type; uneven loading causes cold leaks that appear only after the line reaches operating temperature.
Factory acceptance testing includes shell hydrostatic test at 1.5 times rated pressure and seat leakage test per API 598 or EN 12266. Cryogenic seat leakage verification on a cold test bench may be specified for critical LNG block-valve duty. Pre-commissioning field checks include a full stroke cycle under dry nitrogen purge, gear operation verification and confirmation that position indication matches disc orientation before cold introduction.
Selection checklist for procurement engineers
Confirm nominal size, flange standard (ANSI / DIN / EN / JIS), pressure class and design temperature including minimum operating and upset conditions. State the cryogenic medium—LNG, ethylene, LOX, LIN or other—to enable material and cleaning compatibility review. Specify leakage class, flow direction if unidirectional, and whether cryogenic seat test documentation is required. Indicate actuator type, fail position and area classification for hazardous locations. Provide insulation type and thickness so stem extension length and operator clearance are dimensioned correctly. Request material certificates, pressure test reports and low-temperature impact test data with the delivery package.
Product parameters summary
Model series: low temperature cryogenic treatment flange butterfly valve, triple offset metal hard seal
End connection: double flanged (RF / FF per standard)
Nominal diameter: 2″–48″ (DN50–DN1200)
Pressure class: ANSI 150/300; PN16/25/40; JIS 10K/20K
Temperature range: the qualified minimum and maximum design temperatures of the actual valve assembly (configuration dependent)
Seat type: metal hard seal, bubble-tight within rated cold envelope
Drive: worm gear manual; chain wheel, electric or pneumatic optional
Body / disc: LCB, LCC, CF8, CF8M or project cryogenic alloy
Brand: Trekre Valve — industrial butterfly valves made in China
Contact Trekre Valve with your cold-service data sheet for cryogenic flange butterfly valve sizing, material selection and delivery schedule from our Wuxi factory.
Frequently Asked Questions
Does cryogenic treatment alone qualify this valve for my liquefied-gas service?
Do not infer service qualification from the treatment description. Provide the actual medium and design conditions and request the exact valve’s material, design, test and operating documentation for review.
How do I confirm the minimum operating temperature for my order?
Ask for the approved pressure-temperature limits of the complete selected body, trim, seat and sealing arrangement. Do not use a material-treatment temperature or a general series example as the valve’s operating rating.
What installation information should I supply for the extended or cold-service arrangement?
Send the piping orientation, insulation details and available operating and maintenance space. Request the exact assembly drawing and cold-service installation requirements rather than assuming one arrangement suits every application.