Trunnion Mounted Ball Valves
Trunnion-mounted ball valves are quarter-turn isolation valves in which the ball is anchored by shafts, or trunnions, at the top and bottom. Because the ball is fixed, line pressure does not push it onto the downstream seat; instead, spring-energised seats are pressed against the ball. This keeps operating torque low and largely independent of line pressure, which is what makes the design suited to large bores and high-pressure service.
Trunnion designs dominate from about 4" upward and across higher pressure classes, with pipeline valves commonly built to API 6D in ASME 150 through 2500. Many feature self-relieving or double-piston-effect seats that give inherent double-block-and-bleed capability, a body cavity relief path, and emergency sealant injection ports on larger valves. Shell and seat testing follows API 598, with ASME B16.34 setting the pressure-temperature envelope; API 6FA or API 607 fire testing is specified for hydrocarbon and ESD duty.
Bodies are typically A216 WCB or LCC carbon steel, A351 CF8M stainless, and duplex, super-duplex or nickel alloys such as Inconel and Monel for sour or corrosive pipeline service. Seat inserts use reinforced PTFE, nylon, PEEK or metal-seated tungsten-carbide overlays for severe and abrasive media. End connections are predominantly butt-weld and flanged ANSI B16.5/B16.47 RF or RTJ across the 150 to 2500 range.
Large trunnion valves are usually gear-operated or fitted with pneumatic scotch-yoke, electric or hydraulic actuators, including spring-return fail-safe and fire-safe API 607/6FA constructions for emergency shutdown, where specified.
Himalay's MSME partners manufacture trunnion-mounted ball valves with testing per API 598, BS EN 12266-1 and ISO 5208, material traceability, and PED-CE (EU), SABER (Saudi Arabia) and NACE MR0175 (sour service) coordinated as part of the standard order flow.
