Low Temperature Flanged Trunnion Mounted Ball Valve

Low Temperature Flanged Trunnion Mounted Ball Valve

Design Features

Trunnion-mounted design: the ball is fixed by upper and lower trunnions and does not float under line pressure; the seats are spring-loaded and energised by medium pressure, giving low torque and reliable sealing in large-size, high-pressure-differential service.

Extended bonnet: the bonnet is axially extended so that the packing box operates above -29 C (calculated from the fluid temperature and insulation thickness), avoiding cold brittle failure of PTFE / flexible graphite packing and enabling cryogenic service down to -196 C.

Cryogenic material: body and bonnet are cast in CF8 (ASTM A351 CF8, equivalent to 304) or CF8M (equivalent to 316) stainless steel, verified by low-temperature impact tests for excellent cryogenic toughness.

Side-entry / two-piece body: bolted side-entry construction allows in-line maintenance; DBB (double block and bleed) function with cavity pressure relief.

Cavity pressure relief: if abnormal temperature rise on the downstream side causes trapped cavity pressure, the downstream seat automatically relieves to the line side, protecting the body and piping.

Fire-safe design: seats combine PTFE / RPTFE with a metallic soft-back ring, meeting API 607 / ISO 10497 fire-safe testing and maintaining emergency sealing after a fire.

Anti-static device: anti-static springs and a conductive ball are installed between ball, stem and body to ground static charge and reduce ignition risk.

Blow-out-proof stem: the stem is shoulder-guided with a back seat and cannot be ejected under line pressure, ensuring operator safety.

Emergency sealant injection: sealant injection fittings are provided at the stem and seat for on-line emergency sealing in case of packing or seat damage.

Low-emission packing: flexible graphite + PTFE live-loaded packing stem sealing meets ISO 15848 fugitive-emission requirements.

Multiple actuation options: manual gear operator, pneumatic (single / double acting), electric or gas-over-oil actuator, suitable for remote control and SIS safety interlock.

Technical Specifications

Size range: 2" to 56" (DN50 to DN1400)

Pressure class: Class 150 to Class 2500 (PN20 to PN420); Class 1500 / 2500 available for special service

Temperature range: -196 C to +100 C (cryogenic type; extended ambient type up to +200 C)

Body material: CF8 (cast 304), CF8M (cast 316)

Ball material: CF8M / 316 stainless steel, optional hard chrome plating (ENP) or Stellite overlay

Stem material: F304 / F316 stainless steel, verified by low-temperature impact and hardness tests

Seat seal: PTFE, RPTFE, Nylon (Devlon), PEEK, metal-to-metal (M&M)

End connection: flanged RF / RTJ, to ASME B16.5 / EN 1092

Actuation: manual gear, pneumatic (single / double acting), electric, gas-over-oil

Design standard: API 6D, ASME B16.34, BS 6364 (cryogenic valves)

Face-to-face: ASME B16.10, API 6D

Test & inspection: API 598, API 6D, ISO 5208; cryogenic seat test per BS 6364 / MSS SP-134

Fire-safe certification: API 607, ISO 10497

Fugitive emissions: ISO 15848-1 / -2

Applications

LNG industry: used on cryogenic lines at LNG receiving terminals, liquefaction plants, regasification terminals and LNG fuelling stations for emergency shut-off and safe isolation of LNG service.

Oil & gas: upstream / offshore gathering and transmission, long-distance pipelines and station service, handling sour, wet and high-pressure-differential media.

Petrochemical: cryogenic separation and low-temperature reaction units in ethylene, propylene, ammonia and methanol plants.

Air separation: storage and transfer of liquid nitrogen, liquid oxygen and liquid argon.

LPG & liquid ammonia: low-temperature atmospheric storage tanks, truck loading arms and pump discharge lines.

Refrigeration & cold chain: large cold storage, chemical refrigeration systems and CCUS low-temperature service.

General low-temperature industry: shut-off and on-off control of water, oil, gas and other cryogenic liquid media.

Advantages & Value

Cryogenic reliability: the extended bonnet together with impact-tested CF8 / CF8M cast stainless steel ensures long-term -196 C service with an ice-free, non-brittle packing box.

Large-bore, high-pressure capability: the trunnion design keeps bending loads off the ball, reducing operating torque well below floating ball valves in DN300+ and Class 600+ service, allowing smaller, more energy-efficient actuators.

Long seat life: spring-loaded seats, self-relieving design and fire-safe metal backup ring maintain low leakage after repeated cycles and reduce on-line maintenance.

Intrinsic safety: combined fire-safe, anti-static, blow-out-proof stem and cavity-pressure-relief design meets the most stringent LNG industry safety codes.

Low maintenance: side-entry body allows in-line overhaul; injection fittings provide on-line emergency sealing and avoid unplanned shutdowns.

System integration: can be fitted with pneumatic / electric actuators, limit switches, solenoid valves and positioners for direct DCS / SCS / SIS integration and smart-station use.

Compliant delivery: manufactured and tested to API 6D and BS 6364; EN 10204 3.1 material certificates, low-temperature impact reports and fire-safe / low-emission test reports available to satisfy international owner and EPC requirements.