Trunnion vs. Floating Ball Valve: A Detailed Comparison

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Bruce Zheng

Hi, I'm Bruce Zheng. I am pleased to offer you the best Valves with strict quality control in NTVAL.

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When selecting the right ball valve, do you know whether a trunnion or floating ball valve is the better choice? Choosing the right one can make a big difference in how well your system works and how safe it is.

As a Process Engineer, I’ve worked a lot with both types of valves and know their strengths and weaknesses. This hands-on experience allows me to offer you clear and helpful advice.

The key difference between trunnion and floating ball valves is how they manage pressure. Trunnion valves are ideal for high-pressure systems, while floating ball valves are best suited for lower-pressure setups.

In this guide, you’ll learn the main differences, benefits, and helpful tips for choosing the right valve. By the end, you’ll know how to make the best choice for your needs.

So, let’s get started!

1. What is a Trunnion Ball Valve?

A trunnion ball valve is a special type of ball valve that has extra support to help it work better under pressure. Picture a ball in a socket, but with poles at the top and bottom to keep it steady. These poles are called trunnions. The trunnions hold the ball in place, making it easier to turn, especially when there’s a lot of pressure in the pipe.

Components

  • Trunnion: A key support mechanism that anchors the ball, providing stability during operation.
  • Ball: A spherical component with a hole through the center that rotates to control the flow of liquids or gases.
  • Seats: Rings that surround the ball, creating a tight seal when the valve is closed to prevent leaks.
  • Stem: Connects the ball to the external control mechanism, such as a handle or actuator, allowing easy operation.
  • Body: The main structure that houses all internal components, providing protection and structural integrity.
  • Bonnet: The cover that encloses the top of the valve, securing the stem and offering additional protection.
  • O-Rings and Gaskets: Sealing elements that prevent leaks by filling gaps between different parts of the valve.
  • Drain and Vent: Systems that allow for the release of trapped fluids or gases, useful for maintenance or depressurization.
Trunnion vs. Floating Ball Valve: A Detailed Comparison 1

Features and Benefits

FeatureBenefit
DurabilityLong-lasting performance even in harsh industrial environments, reducing the need for frequent replacements.
High-Pressure HandlingCapable of withstanding and operating effectively in high-pressure systems, making it ideal for critical applications.
Double Block and BleedAllows for pressure relief on one side of the valve without interrupting the flow, enhancing safety during maintenance.
Stability from Trunnion SupportKeeps the ball stable under high pressure, providing consistent operation and reducing the risk of valve failure.
Tight Sealing SeatsPrevents leaks, keeping fluids or gases contained, which is crucial for safety and efficiency.
Versatile OperationCan be operated manually or with an actuator, offering flexibility for different system requirements.
Drain and Vent SystemsFacilitates easy maintenance and safe depressurization, reducing downtime and improving operational safety.

2. What is a Floating Ball Valve?

A floating ball valve works a bit differently from a trunnion ball valve. Imagine the ball inside the valve can move slightly, like it’s floating. There are no trunnions holding it in place. Instead, the pressure of the liquid or gas pushes the ball tightly against the valve’s edges, creating a seal to stop the flow.

Components

  • Floating Ball: The ball is not anchored, allowing it to move slightly within the valve body. This movement helps the ball press against the seats, creating a tight seal when the valve is closed.
  • Seats: The sealing rings that the floating ball presses against to prevent leaks. The seats provide a secure seal, particularly in low to medium pressure applications.
  • Stem: The stem connects the floating ball to the valve handle or actuator, allowing the operator to open or close the valve. The design of the stem enables smooth operation.
  • Body: The valve body houses all the internal components, providing necessary structure and protection.
  • Bonnet: The bonnet covers the top part of the valve, securing the stem and offering additional protection to the internal components.
  • O-Rings and Gaskets: These components seal any gaps within the valve, preventing leaks around the stem and other connections.
  • Handle or Actuator: The external mechanism used to operate the valve, allowing for manual or automated control of the valve’s position.

Features and Benefits

FeatureBenefit
Simple DesignOffers ease of operation and maintenance, which reduces downtime and lowers maintenance costs.
Low to Medium Pressure HandlingIdeal for applications with lower pressure, providing reliable performance without overengineering.
Self-Adjusting SealingThe floating ball adjusts to the pressure, creating a tight seal that prevents leaks, especially useful in low-pressure systems.
Cost-EffectiveTypically less expensive than trunnion ball valves, making it a budget-friendly option for less demanding applications.
Quick OperationAllows for fast opening and closing, which is beneficial in emergency shutoff situations.
Compact and LightweightEasier to install and requires less space, making it suitable for installations with space constraints.
Versatile ApplicationCan be used in various systems, including water, gas, and chemicals, offering flexibility across different industries.

3. Key Differences Between Trunnion and Floating Ball Valves

Trunnion and Floating ball valves differ primarily in how they handle pressure and how the ball is supported within the valve. These differences impact their suitability for various applications, which are highlighted in the table below:

AspectTrunnion Ball ValveFloating Ball Valve
Ball SupportBall is anchored by a trunnion for stabilityBall is free to float, adjusting to line pressure
Pressure HandlingIdeal for high-pressure applicationsBest suited for low to medium pressure systems
Sealing MechanismRelies on trunnion support and seats for a consistent sealThe ball adjusts to press against the seats for sealing
CostTypically more expensive due to complex designGenerally more cost-effective, simpler design
MaintenanceRequires more maintenance due to additional componentsEasier to maintain with fewer moving parts
Application FlexibilityPreferred in critical, high-pressure environmentsVersatile, used in a wide range of general applications
Size and WeightLarger and heavier due to the trunnion supportMore compact and lightweight
OperationOften used with actuators for remote controlCan be operated manually or with actuators

4. 6 Tips for Choosing the Right Valve for Your Application

Choosing the right ball valve for your industrial application is crucial for efficient operation, safety, and cost-effectiveness. Here are some tips to help you decide:

#1 Pipe Size

The size of your pipes also affects valve choice. Trunnion Ball Valves handle larger pipes better because they provide more support, while Floating Ball Valves are suited for smaller pipelines. For instance, if you’re managing a large gas distribution system, a Trunnion Ball Valve is the right choice.

#2 Operating Torque

The force needed to operate the valve can differ between the two types. Floating Ball Valves usually require higher torque due to the ball’s movement under pressure, while Trunnion Ball Valves are easier to operate because of their fixed design. For example, in a manually operated system, a Trunnion Ball Valve would be easier to control.

#3 Temperature Tolerance

If your system handles extreme temperatures, a trunnion ball valve might be a better fit. Trunnion designs can handle a wider range of temperatures because they distribute pressure more evenly. Floating ball valves, while functional in moderate temperature ranges, may not hold up as well in extreme conditions, leading to potential leaks or damage.

#4 Type of Media

The kind of liquid or gas you’re working with can influence your choice. Trunnion ball valves work better for thicker, more viscous media like oil because they have a more secure, supported sealing mechanism. For lighter, less viscous fluids like water or gas, a floating ball valve can handle the job effectively without needing extra support.

#5 Safety and Compliance

Choose a valve that meets industry safety standards and regulations. Trunnion ball valves are often required in applications where fail-safe operation is critical, such as in emergency shutdown systems. Floating ball valves, while also safe, may be more appropriate in less critical, lower-risk environments. At NTVAL, we make sure our valves are safe and reliable. Our valves are certified by ISO 9001 for quality and API 6D for pipeline standards.

#6 Installation Space

Finally, take into account the physical space where the valve will be installed. Trunnion ball valves tend to be bulkier due to their additional support components, so they may require more installation space. Floating ball valves, being more compact, are better suited for applications where space is tight.

Conclusion

Choosing the right valve for your system can seem overwhelming, especially when it affects both pressure and performance. Now that you know the key differences between trunnion and floating ball valves, you now have a clear idea of which option suits your needs best.

In conclusion, this guide has given you the insights to make a smarter, more informed decision. If you still have questions or need expert advice, we’re here to help. At NTVAL, we offer reliable valves to keep your operations running smoothly. Contact us today to find the best valve for your system!

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