What Are The Advantages Of A Trunnion Ball Valve?

Because of its unique structural design, Trunnion-mounted ball valves have obvious advantages under high pressure, large diameter and harsh working conditions. Its core advantages can be summarized as follows:
I. Stable performance in high-pressure environments
Sphere Retention Design
The trunnion uses upper and lower bearings to hold the sphere in place, preventing high-pressure fluids from pushing the sphere toward the valve seat, thus dispersing pipe thrust and preventing excessive wear on the sealing surface.
Typical application: In long-distance oil and gas pipelines (up to 2500 pressure levels), the ball valve mounted on trunnion-mounted ball valves can operate steadily for a long time, reducing the risk of leakage.
Low Operating Torque
Since the ball is fixed, only friction between the valve seat and the ball needs to be overcome during opening and closing, while floating ball valves require additional force to overcome fluid pressure on the ball.
Data comparison: Under the same diameter and pressure, the working torque of the ball valve mounted on the shaft neck is 30%-50% lower than that of the floating ball valve, especially for large diameter valves (e.g., NPS 24 and above).
ii. Adapt to Large Diameters and high Flow Rates
Optimized Structural Strength
The trunnion support structure distributes the weight of the ball and the fluid impact, making the valve body design more compact in design without the need for additional wall thickness to withstand pressure, thus reducing weight and cost.
Application example: In large-diameter unloading pipelines of LNG terminal, trunnion-mounted ball valves mounted on electronic tube can handle cryogenic fluids at -162 ℃ while maintaining lightweight design.
All-port design
Trunnion-mounted ball valves are generally designed with a full port, and their internal flow path diameter matches the diameter of the pipe, reducing fluid resistance, reducing pressure drop, and improving system efficiency.
Advantages: Full port design can prevent media deposition and reduce the risk of blockage during chemical processes.
III. Bidirectional Sealing and multiple safety features
Bidirectional Sealing Capability
Trunnion-mounted ball valves can be equipped with DBB (double and double seat) or DIB (double seat isolation and double seat) valve seats to achieve a bidirectional sealing in and out. Functional differences:
DBB: Seated independently on both sides of the seat; central cavity decompresses pressure and is suitable for applications requiring media to be expelled from the valve cavity (e.g., steam pipelines).
DIB: Seal both sides of the valve seat; even if one fails, the other can isolate the medium for high-risk applications (e.g., nuclear power plant cooling systems).
Fire Safety Design:
trunnion ball valves are usually constructed of a combination of metal and soft sealing material, PTFE). metal seal provide secondary protection when soft seals fail.
Standard certification: complies with fire testing standards such as API 6FA and ISO 10497 and maintains sealing performance after fire.
IV. INTRODUCTION High temperature and Corrosion Resistance
Material Compatibility:
The trunnion, spheres and valve seat can be made of high-temperature resistant alloys (e.g. Inconel 625) or corrosion resistant materials (e.g., Hastelloy) suitable for extreme conditions.
Typical applications: In catalytic cracking units in refineries, trunnion ball valves can handle high-temperature oil and gas media at 800°C.
Seal reliability:
Metal seat stopper ball valve adopts spring preload or media pressure seal the ball. the preload maintains the valve seat sealed even after prolonged use and wear.
Life Span Advantage: in coal chemical gasification plants, metal-seated trunnion ball valves service life can be more than 10 years.
V. Low Maintenance, long life.
Online maintenance capabilities:
Trunnion ball valve supports online valve seats replacement without removing the entire valve, reducing downtime.
For example, in spatially restricted environments such as ocean platforms, valve seat can be replaced directly through the top flange, reducing maintenance costs.
Abrasion resistant design:
The spheres and valve seat are encased in hard carbide (e.g., tungsten chromium cobalt 6) and have a surface hardness exceeding HRC 60, which greatly improves abrasion resistance.
Data comparison: in the pipeline of abrasive, the service life of carbide sealed a trunnion ball valve is 3-5 times that of ordinary valves.
VI. INTRODUCTION Automation Control Compatibility
Actuator Compatibility:
The operating torque of trunnion ball valves is low, so it can be matched with electric, pneumatic, or hydraulic actuators for remote automation control. Application Case: In intelligent water management system, trunnion-mounted ball valves installed in water tank can be monitored by SCADA systems in real time to improve management efficiency.
Quick on and off feature
Some ball valves mounted on Some trunnion-mounted ball valves can be equipped with pneumatic actuators that can open and close in milliseconds and are suitable for applications that require rapid closure of fluids (e.g., fire suppression systems).
Comparison Summary of Trunnion-Mounted Ball Valves and Floating Ball Valves
Characteristic Trunnion-Mounted Ball Valve Floating Ball Valve
Suitable for high pressure (Class 600-2500), medium low pressure (≤ 600)
Large diameter (NPS 2-60) small to medium diameter (≤NPS 8)
Bidirectional sealing seal (DBB/DIB) Unidirectional sealing (depending on fluid pressure)
Low operational torque (30%-50% less than floating ball valves) (high torque required under high pressure)
Maintenance Cost Moderate (support online maintenance) Low (simple structure but frequent replacement)
Oil, gas, chemicals, electricity,Water supply and drainage, HVAC, low-pressure gas pipelines