A trunnion ball valve is a type of valve that uses a rotating ball as its core control element. The flow of media is controlled by the contact or separation of the ball and the valve seat. The "trunnion" in its name refers to the support shaft structure located on both sides of the ball. This design gives it unique advantages in high-pressure, large-diameter, and complex operating conditions, making it a key piece of equipment in the field of industrial fluid control. GNEE Group provides custom-designed trunnion ball valves; please send us your drawings for consultation.
Customized trunnion ball valve drawings for UAE customer
trunnion ball valve Design and Core Components
The structural design of imported trunnion-type ball valves revolves around "stability" and "sealing." Its core components include the ball, trunnion, valve seat, valve stem, and valve body:
- Ball: The ball surface is machined with a circular through-hole, the diameter of which matches the pipe's inner diameter, ensuring minimal fluid resistance when fully open. The ball is typically made of stainless steel, carbon steel, or a corrosion-resistant alloy to suit different media requirements.
- Truncuse: Symmetrically positioned support shafts (trunnions) on both sides of the ball are connected to the valve body via bearings, forming a fixed structure. The trunnion not only restricts the ball's axial displacement but also reduces operating torque through rigid support, allowing the valve to open and close easily even under high pressure.
- Valve Seat: The valve seat employs a spring-loaded design, automatically compensating for wear and maintaining sealing pressure. Some high-end models have lubrication ports around the valve seat, allowing lubricant injection to reduce friction during closure and extend service life.
- Valve Stem: The valve stem is connected to the trunnion via a key, transmitting the rotational torque from the drive unit (manual, pneumatic, or electric). The valve stem seal utilizes a stuffing box structure with a spring-loaded design to effectively prevent media leakage.
- Valve Body: The valve body is typically a one-piece cast or forged structure, with a material matching the ball to ensure pressure resistance. Its internal flow channel design is optimized to reduce fluid turbulence and lower pressure drop.
Performance Advantages
High Pressure Adaptability
Ternary ball valves can withstand Class 1500 (25MPa) and even higher pressure ratings, suitable for high-pressure scenarios such as oil and gas extraction and refining plants. The valve body is forged, and the wall thickness design conforms to ASME B16.34 standards, ensuring structural strength.
Wide Temperature Range
Valve body materials can be selected from carbon steel (WCB), cryogenic steel (LCC), or high-temperature alloy (Inconel), adapting to extreme temperature environments from -196℃ to 600℃. For example, in LNG receiving terminals, cryogenic inlet trunnion ball valves can operate stably at -162℃.
Wear Resistance and Long Service Life
The ball surface is coated with hard alloy (such as Stellite 6), achieving a hardness of HRC 60 or higher, effectively resisting media erosion. In media containing solid particles (such as coal slurry and mineral slurry), its service life can be 3-5 times that of floating ball valves.
Rapid opening and closing with low leakage
Opening and closing can be completed with a 90° rotation, and the response time is less than 5 seconds. It passes API 607 or API 6FA fire resistance tests and maintains a seal even under fire conditions, with a leakage rate of less than 10 ppm.
Applications
Oil & Gas Industry
Used for high-pressure shut-off and flow regulation in wellhead equipment, oil pipelines, and refining units. For example, in deep-sea oil and gas development, imported trunnion ball valves can withstand high pressure and corrosive media on the seabed.
Chemical Industry
Suitable for conveying highly corrosive media (such as sulfuric acid and chlor-alkali). Valve body materials can be selected from Hastelloy (C-276) or titanium alloy, and the valve seat uses a PTFE+graphite composite seal.
Power and Heat
In supercritical thermal power units, imported trunnion ball valves are used for the isolation of steam pipelines, with a temperature resistance up to 600℃ and a pressure rating up to Class 2500.
Water Treatment
Used in seawater desalination, sewage treatment, and other applications. The valve body is made of duplex stainless steel (2205), offering excellent resistance to chloride ion corrosion.
GNEE trunnion ball valves are suitable for various pipelines and high temperatures. Contact us for custom trunnion ball valves.