Quick specifications
- DesignTrunnion-supported ball
- Size rangeUp to 24"
- Pressure classUp to ASME 2500
- BodyCS, forged steel, SS
- OperationGearbox, pneumatic, electric
In a trunnion mounted ball valve, the ball is held by a stem at the top and a trunnion at the bottom, so it rotates but cannot move downstream. Spring-loaded seats move onto the ball to seal. Because line pressure is carried by the trunnion rather than the seats, the valve needs far less torque than a floating ball valve of the same size – making it the standard choice for large-diameter and high-pressure pipelines.
Floating vs trunnion mounted
| Floating ball | Trunnion mounted | |
|---|---|---|
| Ball support | Held by seats | Stem + trunnion |
| Typical sizes | Small to medium | Medium to large |
| Operating torque | Rises with pressure | Lower, more stable |
| Seat load | Line pressure on downstream seat | Spring-loaded seats |
| Cost | Lower | Higher |
More in our floating vs trunnion guide.
Operation
Trunnion valves are usually gear operated or automated. We supply them with manual gearboxes, pneumatic actuators or electric actuators sized to the valve's torque.
Trunnion Mounted Ball Valve – technical specifications
| Body material | Carbon Steel, ASTM A105 (forged); forged steel; SS304 / SS304L, SS316 / SS316L, SS410, Duplex SS |
|---|---|
| Size range | Up to 24" (600 mm) |
| Pressure rating | ASME Class 150 to 2500 / PN16 to PN420 |
| End connections | Flanged ANSI / DIN / BS, Butt Weld |
| Seats | Spring-loaded; RPTFE, PEEK or metal as specified |
| Operation | Gearbox, pneumatic, electric, hydraulic |
| Temperature | –29 °C to +550 °C body range; actual limit set by seat and seal material |
| Testing | API 598 / API 6D |
Ranges shown cover the product family. The exact rating, size and temperature limit for your valve depend on body material, seat material and design, and are confirmed in our quotation and datasheet.
Key benefits
- Low, predictable operating torque
- Smaller actuators for automation
- Reliable sealing at high pressure
- Suitable for large-diameter pipelines
- Long seat life
Applications
- Oil and gas transmission and gathering lines
- Refinery and petrochemical units
- Large water mains and pumping stations
- Power plant fuel and cooling systems
Industries served
Frequently asked questions
When should I use a trunnion mounted ball valve?
For larger sizes and higher pressure classes, where a floating ball valve would need excessive torque or the seats would be overloaded.
Are trunnion ball valves always gear operated?
Most are gear operated or actuated due to their size. Smaller trunnion valves can be lever operated.
Do you offer forged trunnion ball valves?
Yes, trunnion mounted designs are part of our forged ball valve range.
