Oil & Gas
Pipeline block and station isolation valves with API 6D documentation.
Ball Valve · Trunnion-Mounted
Trunnion-mounted ball valves fix the ball on upper and lower bearings so spring-loaded seats — not line pressure — drive sealing, giving lower and more consistent torque at high pressure and large bore. Worm gear operators for trunnion valves carry pipeline duty with API 6D documentation, heavy-duty housings, and declutchable manual override.
Application Foundation
A trunnion ball valve gear operator actuates valves whose ball is supported on top and bottom trunnion bearings. Because the bearings carry pipeline load and the seats are spring-energised against the ball, torque stays lower and more consistent through the stroke than on floating designs — but pipeline block valves are large and high-pressure, so absolute torque is still substantial.
Size the operator from the trunnion-valve torque curve across the full stroke, including bearing and seat friction, then match the ISO 5211 flange and stem. Trunnion valves on transmission and process lines often need Matson models M14–M16 (1,800–4,400 N·m) or two-stage heavy-duty units, with declutchable override where electric actuators are fitted.
Engineering Data
| ISO 5211 Flange | Typical Valve Size Band* | Common Valve Families | Matson Models Offering This Flange |
|---|---|---|---|
| F05 | Small bore | Ball, plug, small butterfly | M07 |
| F07 | Small–medium bore | Butterfly (wafer), ball, plug | M07, M10 |
| F10 | Medium bore | Butterfly, ball, plug | M07, M10, M12 |
| F12 | Medium bore | Butterfly (lug), ball, gate top-work | M12, M14 |
| F14 | Medium–large bore | Butterfly, trunnion ball, gate | M12, M14, M14A, M15 |
| F16 | Large bore | Butterfly (double flange / AWWA), ball, gate | M14, M14A, M15, M16 |
| F25 | Heavy / large bore | Large AWWA butterfly, high-pressure ball, large gate | M16 |
*Valve size band is indicative only — actual flange depends on the valve manufacturer's top-work, stem, and torque rating. Flange options and Matson single-stage model data are from the Matson worm gearbox catalog (M07–M16, 200–4,400 N·m). Two-stage and electric-actuator series extend up to 160,000 N·m. Confirm the exact flange against your valve datasheet.
| Variant | Actuation | Typical Torque Driver | Mounting Interface |
|---|---|---|---|
| Trunnion ball | Quarter-turn 90° | Bearing + spring-seat friction (consistent) | ISO 5211 F12–F25 |
General selection guidance by torque demand and top-flange interface. Match the required break-to-open torque (with safety factor) and the valve top-work flange to a Matson model; exact model and dimensions are confirmed against your valve datasheet — request a datasheet.
Per-model specifications (dimensions, weights, drive bushing details): available on request — request a datasheet. Send your valve tag, bore, pressure class, and required output torque and our engineers return a model recommendation with the matching ISO 5211 interface.
Operation
Size on the full-stroke torque curve, not just break-to-open, for trunnion valves.
Confirm API 6D documentation and witness-test requirements for pipeline service.
Specify declutchable override and actuator-ready bases for automated block valves.
Engineering
By Industry
Pipeline block and station isolation valves with API 6D documentation.
Mainline and metering-station isolation.
Process unit isolation and emergency block valves.
Loading and tank-farm isolation.
Manufacturing Partner
Operators sized against real valve torque charts and top-work drawings — not generic catalog tables.
Standard and adapter mounting for current and legacy valve patterns without field rework.
Private label, locked BOM, and volume pricing for valve OEM and distributor programs.
STEP models, center-height tables, and export certificates issued with the commercial quote.
Common Questions
The trunnion in a ball valve is a fixed support on the top and bottom of the ball that carries the pipeline thrust on bearings. This keeps the ball centred so spring-loaded seats — not line pressure — energise the seal, giving lower and more consistent operating torque at high pressure and large bore than a floating ball valve.
A trunnion ball valve includes the body, a ball fixed on upper and lower trunnion bearings, spring-energised seats, the stem, and the top mounting flange. The trunnions carry line load; the spring seats maintain sealing. A worm gear operator mounts on the ISO 5211 flange to actuate the stem.
A valve gearbox uses a worm and worm-wheel to turn many handwheel revolutions into a controlled 90° stem rotation while multiplying torque. The set is self-locking, so the valve holds position without back-driving — essential for large trunnion block valves under pipeline pressure.
A gear-operated valve places a gearbox between the handwheel and stem to multiply torque and hold position. On trunnion ball valves, a worm gear operator lets one person actuate large high-pressure block valves and provides an ISO 5211 base for electric actuation.
Match the operator to the trunnion valve's full-stroke torque curve and ISO 5211 flange (often F12–F25). Matson models M14–M16 (1,800–4,400 N·m) and two-stage heavy-duty units cover pipeline duties. Provide the valve datasheet and API 6D requirements for sizing.
Send your trunnion ball valve bore, pressure class, torque curve, and API 6D requirements. We size a heavy-duty worm gear operator with documented torque margin and witness-test options.