Soft Seated Flanged Trunnion Ball Valve

The Soft Seated Flanged Trunnion Mounted Ball Valve is engineered for reliable, bubble-tight shut-off in high-pressure, high-cycle industrial pipeline systems.
Unlike floating ball valves, the trunnion-mounted design supports the ball on both upper and lower trunnions, allowing it to remain mechanically fixed while the seats move to seal. This structure significantly reduces operating torque and improves sealing stability under fluctuating pressure conditions.

In traditional floating ball valves, upstream pressure forces the ball into the downstream seat, which increases friction and limits performance in large sizes and high-pressure classes.
The trunnion-mounted structure solves these limitations:
Mechanical Load Support
The ball is anchored by precision-machined upper and lower trunnions, transferring hydraulic load directly to the valve body bearings instead of the seats.
Low Friction Operation
Because axial movement is eliminated, seat compression is controlled and stable, significantly reducing torque requirements.
Stable Sealing Performance
The seat system remains aligned even under:

• High differential pressure
• Pressure surges and spikes
• Bi-directional flow conditions

Low Torque Design for Automation Systems
The trunnion structure makes the valve highly suitable for automation systems, including:
Pneumatic actuators (Scotch Yoke / Rack & Pinion)
Electric actuators (On/Off & Modulating)
Electro-hydraulic systems
Gear-operated manual systems
Engineering benefit for EPC projects:
Lower torque requirement reduces actuator size and cost, improving total project economics.

Double Block and Bleed (DBB) Function
The valve is designed to achieve independent upstream and downstream sealing, enabling safe cavity venting through drain/vent ports.
This allows operators to:
Verify seat integrity
Isolate pipeline sections safely
Perform maintenance without full shutdown

High Pressure Sealing Stability
The seat system uses spring-loaded energization combined with line pressure assistance.
This ensures:
Bubble-tight sealing (API 598 / ISO 5208 Rate A)
Reliable sealing under low-pressure conditions
Stable performance under high-pressure fluctuations

Fire-Safe & Anti-Static Design
For hazardous service applications, the valve can be designed and tested in compliance with:
API 607
API 6FA
Safety features include:
Metal-to-metal secondary sealing in fire conditions
Anti-static grounding between ball, stem, and body
Blowout-proof stem design

Full Bore & Reduced Bore Options
Full Bore (FB):
Same internal diameter as pipeline, supports pigging and minimizes pressure drop.
Reduced Bore (RB):
Compact design with reduced weight and cost, suitable for general industrial isolation.

Each valve is manufactured under strict quality control procedures:

• 100% Hydrostatic shell test (1.5× design pressure)
• Seat leakage test (zero-leakage verification)
• Dimensional inspection (CNC precision verification)
• Material traceability via heat number tracking
• EN 10204 3.1 certification provided for all pressure parts

This valve is widely used in global industrial systems, including:

We support global EPC contractors, distributors, and OEM partners with:

• Custom engineering per API / ASME / EN / JIS standards
• OEM branding and private label casting
• Fast production scheduling for project orders
• Export-grade packaging and documentation
• Full technical submittal package (GA drawings, torque charts, IOM manuals)

To support global procurement projects:

Our trunnion ball valves are commonly supplied for:

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