Floating Ball Valve vs Trunnion Ball Valve Which One Do You Really Need
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In industrial piping systems, ball valves are widely used due to their ease of operation and reliable sealing. However, when it comes to the two main types—Floating Ball Valves and Trunnion Ball Valves—many engineers and procurement professionals often hesitate: which one should they choose? This article provides a detailed analysis of their structural features, applicable operating conditions, and key selection considerations to help you make the most suitable choice.
Features:
● Simple Structure: Compact valve body design with relatively low manufacturing cost.
● Reliable Sealing: Excellent sealing performance in small-diameter and low-to-medium pressure applications.
● Easy Maintenance: Minimal internal components, making seat removal and replacement relatively easy.
Applicable Conditions:
● Nominal diameter generally less than 10 inches (DN250);
● Pressure ratings from low to medium (typically Class150–Class600);
● Commonly used for water, steam, oil, and other low-to-medium pressure media.
Limitations:
● In larger diameters or higher pressures, the ball is subjected to greater medium pressure, increasing opening and closing torque and making operation more difficult;
● Not suitable for high-pressure, large-diameter, or particularly demanding applications.
Features:
● Suitable for Large-Diameter and High-Pressure Applications: The ball is fixed within the valve body, so medium pressure has minimal impact on operating torque.
● Stable Sealing Performance: Trunnion support reduces ball deviation and ensures even seat wear.
● High Expandability: Easily adaptable for actuators (electric or pneumatic) for automated control systems.
Applicable Conditions:
● Large diameters (DN250 and above);
● High pressure (Class900 and above) or extreme operating conditions (e.g., petrochemical or natural gas pipelines);
● Situations requiring frequent operation or automated control.
Limitations:
● More complex structure, leading to higher manufacturing and maintenance costs;
● Not cost-effective for small-diameter, low-pressure applications.
● Small diameter (≤10 inches) and low-to-medium pressure: Floating Ball Valve is preferred.
● Large diameter (>10 inches) and high pressure: Trunnion Ball Valve is more suitable.
Based on Medium Characteristics:
● For media containing particles or with high corrosion potential: Trunnion Ball Valve offers better wear resistance and sealing reliability.
● For low-pressure, clean media: Floating Ball Valve is sufficient.
Based on Operation Method:
● Manual operation: Small-diameter Floating Ball Valve is adequate.
● Automated control or large-diameter applications: Trunnion Ball Valve has clear advantages.
A1: Generally, it is not recommended. In large-diameter, high-pressure applications, Floating Ball Valves require high operating torque, which can accelerate seat wear.
Q2: Are Trunnion Ball Valves always more expensive than Floating Ball Valves?
A2: Yes. Trunnion Ball Valves have a more complex structure and higher material requirements, resulting in higher manufacturing and maintenance costs compared to Floating Ball Valves.
Q3: Is there a significant difference in sealing performance between the two?
A3: For small-diameter, low-pressure applications, Floating Ball Valves provide adequate sealing. In large-diameter, high-pressure conditions, Trunnion Ball Valves offer more stable and reliable sealing.
Q4: If my system might be automated in the future, which type should I choose?
A4: It is recommended to choose a Trunnion Ball Valve, as it is easier to equip with electric or pneumatic actuators and provides greater adaptability.
1. Introduction to Floating Ball Valves
In a Floating Ball Valve, the ball is not fixed within the valve body but is free to float between the upper and lower seats under the pressure of the medium. When the valve closes, the medium’s pressure pushes the ball against the seat, achieving a tight seal.Features:
● Simple Structure: Compact valve body design with relatively low manufacturing cost.
● Reliable Sealing: Excellent sealing performance in small-diameter and low-to-medium pressure applications.
● Easy Maintenance: Minimal internal components, making seat removal and replacement relatively easy.
Applicable Conditions:
● Nominal diameter generally less than 10 inches (DN250);
● Pressure ratings from low to medium (typically Class150–Class600);
● Commonly used for water, steam, oil, and other low-to-medium pressure media.
Limitations:
● In larger diameters or higher pressures, the ball is subjected to greater medium pressure, increasing opening and closing torque and making operation more difficult;
● Not suitable for high-pressure, large-diameter, or particularly demanding applications.
2. Introduction to Trunnion Ball Valves
In a Trunnion Ball Valve, the ball is supported and fixed by trunnions within the valve body, meaning the ball does not rely on the seats to withstand the medium pressure. The seats achieve sealing contact with the ball through springs or other mechanisms.Features:
● Suitable for Large-Diameter and High-Pressure Applications: The ball is fixed within the valve body, so medium pressure has minimal impact on operating torque.
● Stable Sealing Performance: Trunnion support reduces ball deviation and ensures even seat wear.
● High Expandability: Easily adaptable for actuators (electric or pneumatic) for automated control systems.
Applicable Conditions:
● Large diameters (DN250 and above);
● High pressure (Class900 and above) or extreme operating conditions (e.g., petrochemical or natural gas pipelines);
● Situations requiring frequent operation or automated control.
Limitations:
● More complex structure, leading to higher manufacturing and maintenance costs;
● Not cost-effective for small-diameter, low-pressure applications.
3. Selection Recommendations
Based on Diameter and Pressure:● Small diameter (≤10 inches) and low-to-medium pressure: Floating Ball Valve is preferred.
● Large diameter (>10 inches) and high pressure: Trunnion Ball Valve is more suitable.
Based on Medium Characteristics:
● For media containing particles or with high corrosion potential: Trunnion Ball Valve offers better wear resistance and sealing reliability.
● For low-pressure, clean media: Floating Ball Valve is sufficient.
Based on Operation Method:
● Manual operation: Small-diameter Floating Ball Valve is adequate.
● Automated control or large-diameter applications: Trunnion Ball Valve has clear advantages.
4. Conclusion
Both Floating Ball Valves and Trunnion Ball Valves have their advantages. The key to selection lies in factors such as diameter, pressure, medium, and operation method. Understanding their structures and applicable operating conditions can help engineers and procurement professionals avoid selection errors, enhance system reliability, and reduce maintenance costs.Q&A
Q1: Can a Floating Ball Valve withstand high pressure?A1: Generally, it is not recommended. In large-diameter, high-pressure applications, Floating Ball Valves require high operating torque, which can accelerate seat wear.
Q2: Are Trunnion Ball Valves always more expensive than Floating Ball Valves?
A2: Yes. Trunnion Ball Valves have a more complex structure and higher material requirements, resulting in higher manufacturing and maintenance costs compared to Floating Ball Valves.
Q3: Is there a significant difference in sealing performance between the two?
A3: For small-diameter, low-pressure applications, Floating Ball Valves provide adequate sealing. In large-diameter, high-pressure conditions, Trunnion Ball Valves offer more stable and reliable sealing.
Q4: If my system might be automated in the future, which type should I choose?
A4: It is recommended to choose a Trunnion Ball Valve, as it is easier to equip with electric or pneumatic actuators and provides greater adaptability.
