Trunnion Mounted Ball Valves for Critical Flow Isolation
Engineered around a mechanically supported ball design, Trunnion Mounted Ball Valves provide stable operation, dependable shut-off and reduced operating torque for demanding pipeline and industrial isolation applications.
Stable Ball Support for Demanding Applications
A Trunnion Mounted Ball Valve is a quarter-turn isolation valve in which the ball is mechanically supported instead of being free to move downstream under line pressure.
This supported arrangement helps manage pressure forces acting on the ball, reduces loading on the valve seats and makes the design particularly useful for demanding pipeline and process applications.
What Does “Trunnion Mounted” Mean?
The ball is supported around its rotational axis by a stem and trunnion arrangement. Rather than relying on movement of the ball toward the downstream seat, the seat system maintains sealing contact against the supported ball.
Trunnion Mounted vs. Floating Ball Design
The fundamental difference is how the ball is supported and how pressure forces are transferred through the valve.
Mechanically Supported Ball
The ball is held around its rotational axis by the trunnion arrangement. Pressure loads are supported mechanically while the seat system establishes sealing contact with the ball. This helps reduce seat loading and operating torque in demanding applications.
Pressure-Assisted Ball Movement
In a conventional floating ball valve, the ball is not supported by a lower trunnion and can move slightly downstream under differential pressure, pressing against the downstream seat to help establish sealing.
Engineered for Stable & Reliable Operation
The trunnion-supported architecture provides several practical advantages for industrial pipeline isolation.
Supported Ball Design
Mechanical support keeps the ball stable around its rotational axis and helps manage pressure-induced loads.
Reduced Seat Loading
The trunnion arrangement carries significant pressure forces, helping reduce excessive loading between the ball and seats.
Lower Operating Torque
Reduced ball-to-seat loading can make operation more efficient, particularly in larger or higher-pressure valve applications.
Quarter-Turn Operation
A 90-degree rotation moves the ball rapidly between fully open and fully closed positions.
Reliable Shut-Off
The supported ball and seat arrangement is designed to provide dependable process isolation when correctly specified.
Actuation Capability
Depending on configuration, trunnion ball valves can be operated with suitable gear, pneumatic, electric or other actuation systems.
Designed to Manage Pipeline Pressure Loads
In a trunnion-mounted configuration, the ball remains supported while the seat arrangement maintains contact with its sealing surface. This changes how pressure forces are distributed compared with a floating ball valve.
Supports the ball around its rotational axis for stable operation.
Suitable seat arrangements maintain contact against the supported ball to establish shut-off.
Reduced pressure loading on the seats can help lower the torque required to operate the valve.
Valve body, seats, seals, materials and operating system should be selected according to actual process requirements.
How a Trunnion Mounted Ball Valve Works
Flow is controlled through a 90-degree rotation of a mechanically supported ball while the valve seats maintain sealing contact.
Open Position
The bore through the ball aligns with the pipeline, creating an open passage for process fluid.
Stem Rotation
Manual or actuated input rotates the stem, which transfers operating torque to the supported ball.
90° Ball Movement
The ball rotates around its fixed axis until the solid portion of the ball moves across the pipeline flow path.
Seat Sealing
In the closed position, the seat system maintains sealing contact against the supported ball to isolate the process line.
Key Components of a Trunnion Ball Valve
Each component contributes to pressure containment, ball support, sealing and valve operation.
Valve Body
Forms the primary pressure-containing structure and houses the ball, seats and internal components.
Flow Control Ball
A spherical closure element with a through-bore that rotates to open or isolate the pipeline.
Trunnion Support
Provides mechanical support for the ball and helps absorb pressure-induced loads.
Valve Seats
Maintain sealing contact with the ball according to the selected seat design and service conditions.
Valve Stem
Transfers operating torque from the handle, gearbox or actuator to the ball.
Sealing System
Stem, body and internal sealing elements help maintain pressure integrity within the valve assembly.
Why Choose a Trunnion Mounted Design?
The supported ball architecture is particularly advantageous when pressure loads, valve size and operating torque become important engineering considerations.
Stable Ball Position
Mechanical support limits downstream movement of the ball under differential pressure.
Reduced Operating Torque
The supported design helps manage pressure loads and can reduce the force required to operate larger valves.
Suitable for Demanding Service
Trunnion ball valves are commonly selected for higher-pressure and larger-diameter pipeline isolation applications.
Automation Friendly
The quarter-turn mechanism can be integrated with suitable industrial actuation systems for remote operation.
Trunnion Ball Valves for Critical Industries
Trunnion-mounted designs are commonly considered where reliable pipeline isolation, pressure-load management and efficient operation are required.
Oil & Gas
Suitable configurations are widely used for isolation in upstream, midstream and downstream oil and gas systems.
Transmission Pipelines
Commonly used for block and isolation duties in large industrial pipeline networks.
Petrochemical Plants
Applicable to suitable process and utility lines requiring dependable shut-off.
Refineries
Used in compatible hydrocarbon and process isolation applications throughout refinery systems.
Power & Utilities
Suitable configurations can be applied to fuel, water and other compatible utility isolation duties.
Industrial Process Systems
Useful for demanding process applications where stable ball support and reliable isolation are important.
Select the Right Valve for Your Application
Trunnion mounted ball valve selection should be based on actual operating conditions rather than valve size alone.
Size & Flow
Determine pipeline size, required flow capacity and whether full-bore or another flow configuration is required.
Pressure & Temperature
Confirm design and operating pressure and temperature against the selected valve configuration.
Process Medium
Identify the fluid, composition and service characteristics to select compatible body, trim and sealing materials.
Operation Method
Select manual, geared or compatible automated operation according to valve torque and plant requirements.
Trunnion Mounted vs. Floating Ball Valve
Understanding the basic design difference helps determine which ball valve arrangement is more appropriate for the application.
| Design Factor | Trunnion Mounted Ball Valve | Floating Ball Valve |
|---|---|---|
| Ball Support | Mechanically supported around its rotational axis | Ball can move slightly under differential pressure |
| Sealing Principle | Seat system moves or energizes toward the supported ball | Pressure pushes the ball toward the downstream seat |
| Pressure Load | Significant ball load is carried by the trunnion support | Pressure load contributes to ball-to-seat force |
| Operating Torque | Generally advantageous as size and pressure increase | Can increase significantly with pressure and valve size |
| Typical Positioning | Demanding, larger and higher-pressure isolation duties | General small-to-medium industrial isolation duties |
Industrial Valve Solutions for Demanding Applications
FMV Valve Automation provides industrial valve solutions for applications where reliable isolation, process compatibility and dependable valve operation are essential.
Application-Focused Selection
Valve configuration can be discussed according to process, pressure and operating requirements.
Industrial Valve Range
Trunnion mounted ball valves form part of FMV's broader range of industrial flow-control solutions.
Technical Assistance
Share your application parameters to discuss a suitable valve arrangement for the service.
Direct Enquiry Support
Contact FMV with valve size, process medium, pressure, temperature and operating requirements.
Trunnion Mounted Ball Valve FAQs
What is a Trunnion Mounted Ball Valve?
A Trunnion Mounted Ball Valve is a quarter-turn isolation valve in which the ball is mechanically supported around its rotational axis. The supported ball design helps manage pressure loads and allows the seat system to maintain sealing contact with the ball.
How does a Trunnion Mounted Ball Valve work?
The stem rotates the supported ball through approximately 90 degrees. When the bore aligns with the pipeline the valve is open. When the solid ball surface crosses the flow path, the valve closes and the seat system establishes isolation.
What is the difference between floating and trunnion ball valves?
In a floating ball valve, differential pressure can move the ball slightly toward the downstream seat. In a trunnion-mounted design, the ball is mechanically supported and the seat system maintains sealing contact against the ball.
Where are Trunnion Mounted Ball Valves used?
They are commonly used in oil and gas pipelines, petrochemical plants, refineries, power facilities and other demanding industrial process systems.
Why are Trunnion Ball Valves used for demanding pipeline service?
Their supported ball arrangement helps manage pressure-induced loads, reduce excessive seat loading and lower operating torque, which becomes increasingly important in larger and higher-pressure valve applications.
Can Trunnion Mounted Ball Valves be automated?
Yes. Depending on the specific valve configuration and torque requirement, trunnion mounted ball valves can be integrated with suitable pneumatic, electric, hydraulic or other actuation systems.
How do I select a Trunnion Mounted Ball Valve?
Selection should consider valve size, pressure, temperature, process medium, body and trim materials, seat design, end connection, required shut-off performance and operating method.
Need a Trunnion Mounted Ball Valve?
Share your valve size, process medium, pressure, temperature and operating requirements with FMV Valve Automation to discuss a suitable industrial valve solution.