The main difference between these two ball valves is the ball.
Floating ball valves have a ball that moves freely within the valve body, whereas the ball in trunnion valves stays in a fixed position.
This simple design difference and some other key factors affect how each valve performs in various applications.
What is a Floating Ball Valve?
A floating ball valve features a ball that moves freely inside the valve body when pressure is applied.
The ball has no mechanical anchoring system but depends on fluid pressure to push it against the downstream seat, forming a tight seal.
A 3-way ball valve is one common type of floating ball valve design. These valves control flow through three connection ports, making them ideal for mixing, diverting, or blending fluid streams. The ball has special porting that directs flow between these multiple openings.
The simplicity and self-adjusting nature of floating designs make them popular choices for most medium-pressure applications where cost-effectiveness is important.
What is a Trunnion Ball Valve?
A trunnion ball valve features a ball that is mechanically anchored by a shaft (the trunnion) on both top and bottom.
This design prevents the ball from moving or floating within the valve body, even under extreme pressure conditions.
The fixed position of the ball distributes forces more effectively, allowing these valves to handle much higher pressures than their floating counterparts.
Trunnion valves are engineered specifically for demanding applications where reliability under pressure is non-negotiable.
Trunnion Ball Valve vs Floating Ball Valve: Key Differences
The choice between these two valve types depends entirely on your system’s specific requirements. Here’s a comprehensive comparison:
| Feature | Floating Ball Valve | Trunnion Ball Valve |
| Design | Simple, floating ball | Anchored with trunnion support |
| Pressure Handling | Medium | High |
| Torque Requirements | Higher | Lower |
| Applications | Medium-pressure systems | High-pressure or large systems |
| Cost | More affordable | Higher cost |
| Sealing Mechanism | Pressure-assisted | Mechanical |
| Maintenance | Simpler | More complex but durable |
Design and Structure
Floating ball valves have a basic structure with fewer components. The ball moves slightly within the valve body, pushed by pressure to create a seal. This simplicity makes them easier to manufacture and maintain.
Trunnion ball valves incorporate additional supports that minimize ball movement under high pressure. The trunnion anchors the ball in place, ensuring better stability and performance in demanding environments.
Operating Principle
The operating principles of these valves highlight their fundamental differences:
- Floating ball valves rely on fluid pressure to maintain a seal. The pressure pushes the ball against the downstream seat, creating an effective barrier.
- Trunnion ball valves feature a fixed ball that remains stationary, even under intense pressure. The seats provide the sealing action, making these valves more reliable in high-stakes applications.
Pressure Handling Capabilities
One of the most critical distinctions between these valve types is their pressure handling capacity:
- Floating ball valves perform best in medium-pressure environments. When pressure increases beyond their design limits, they may become difficult to operate.
- Trunnion ball valves excel in high-pressure scenarios such as oil and gas operations or petrochemical plants. Their design specifically addresses the challenges of managing powerful fluid flows.
Torque Considerations
Operating torque represents another crucial difference between these valve types.
Floating ball valves require increasingly higher torque as system pressure rises, since the operator must overcome the friction created by the ball being pressed against the seat.
Trunnion ball valves maintain relatively consistent torque requirements regardless of pressure, making them easier to operate manually and more suitable for automation in high-pressure environments.
This lower torque requirement translates to smaller actuators, energy savings, and reduced wear on automation components.
Maintenance Considerations
Maintenance requirements differ significantly between the two valve types.
Floating ball valves offer simplicity with fewer parts, potentially making routine maintenance more straightforward in some cases.
Trunnion ball valves, while more complex, are designed for longevity in harsh conditions and may require less frequent maintenance despite their additional components.
The valve seats in trunnion designs can be replaced without removing the entire valve in many cases, providing a significant advantage in large systems.
Cost Analysis: Floating Ball Valve vs Trunnion Ball Valve
Initial costs typically favor floating ball valves, which can be 30-50% less expensive than comparable trunnion models.
However, the total cost of ownership calculation should consider:
- Expected service life
- Maintenance frequency
- Downtime costs
- Safety implications
- Operational efficiency
In high-pressure applications, the higher initial investment in trunnion technology often pays for itself through extended service life and reduced maintenance needs.
Choosing the Right Ball Valve
When selecting between trunnion vs floating ball valve, consider these factors:
- System pressure: Evaluate your maximum operating pressure. For medium pressures, floating ball valves work well; high-pressure systems require trunnion designs.
- Operation frequency: Systems with frequent valve actuation benefit from trunnion valves’ lower torque requirements.
- Automation needs: If your system requires automation, trunnion ball valves generally provide better performance with actuators.
- Fluid characteristics: Consider the fluid’s temperature, viscosity, and corrosiveness when selecting valve materials.
- Budget constraints: Balance initial costs against long-term operational requirements.
- Application scale: Larger systems typically benefit from the stability of trunnion designs.
Conclusion
These are the fundamental differences between floating ball valves and trunnion ball valves.
Hopefully, you now have more clarity as to which is better suited for your specific needs.
If you’re looking to implement either type in your systems, we have high-quality floating ball valves and trunnion ball valves engineered to meet the most demanding industrial requirements.
Contact us to learn more or discuss your specific valve requirements for your next project.
