In modern industrial piping systems, reliability is not optional — it is essential. When pipelines carry high-pressure fluids, gases, or corrosive chemicals, standard valve designs often struggle to maintain sealing integrity and operational stability. This is where Trunnion Mounted Ball Valves become a preferred solution. Designed to handle extreme pressure, heavy flow loads, and demanding operating conditions, these valves are widely used in oil & gas, petrochemical, power generation, and large-diameter pipeline networks.
What Is a Trunnion Mounted Ball Valve?
A Trunnion Mounted Ball Valve is a type of ball valve in which the ball is mechanically anchored at both the top and bottom by trunnions (support shafts). Unlike floating ball valves, where the ball moves to create sealing pressure, trunnion mounted designs keep the ball fixed while the seats move against the ball to achieve tight sealing.
This construction reduces operating torque and prevents the ball from shifting under high pressure, making the valve ideal for high-pressure, large-diameter, and continuous-duty applications.
Why Trunnion Design Is Superior for Heavy-Duty Applications
The biggest advantage of a trunnion mounted ball valve is load distribution. In high-pressure systems, enormous force pushes against the ball. In floating ball valves, this force transfers to the stem and seats, leading to wear and potential leakage.
In a trunnion design, this load is absorbed by the upper and lower trunnions, keeping the ball perfectly aligned. As a result:
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Stem stress is minimized
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Seat wear is reduced
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Torque remains low even at high pressure
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Sealing performance stays consistent over time
This makes trunnion mounted ball valves extremely reliable for critical services.
Self-Relieving Seats for Enhanced Safety
Trunnion mounted ball valves use spring-loaded or pressure-assisted seats. These seats move toward the ball to maintain a tight seal at low pressure and automatically adjust when pressure increases.
If excessive pressure builds up inside the valve cavity, the seats relieve pressure back into the pipeline, preventing dangerous over-pressurization. This self-relieving feature adds an extra layer of safety, especially in oil, gas, and chemical processing plants.
Typical Applications
Trunnion mounted ball valves are widely used in:
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Crude oil and natural gas pipelines
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Refinery process units
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Petrochemical plants
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LNG and gas transmission systems
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Power generation facilities
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Offshore platforms
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High-pressure water and steam systems
These industries rely on trunnion mounted valves because failure is not an option in such environments.
Key Performance Benefits
Trunnion mounted ball valves provide several technical advantages:
Low operating torque – Actuators and gearboxes work efficiently
Bubble-tight shut-off – Even under extreme pressure
Long service life – Reduced wear on internal components
Fire-safe design – Meets international safety standards
Minimal maintenance – Reliable sealing for years
These features translate into lower operational costs and improved plant safety.
Design Standards and Compliance
High-quality trunnion mounted ball valves are designed and tested according to international standards such as:
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API 6D
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ISO 17292
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ASME B16.34
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Fire-safe certifications
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Fugitive emission standards
Compliance ensures that the valve performs safely even in hazardous environments.
When systems operate under high pressure, high temperature, or continuous flow, valve performance directly affects plant safety and productivity. Trunnion Mounted Ball Valves provide unmatched strength, stable operation, and long-term reliability. Their ability to maintain tight shut-off with low torque makes them a cornerstone of modern industrial flow control.
