A105N Trunnion Mounted Ball Valve is a heavy-duty, high-performance industrial valve designed for high-pressure and large-diameter piping systems.
A105N: The body material is ASTM A105 forged carbon steel, with the "N" signifying that it has undergone Normalizing heat treatment for improved toughness and grain structure.
Trunnion Mounted: Unlike "floating" ball valves, the ball is fixed at the top and bottom by a trunnion (pivot). The pressure of the fluid forces the seats against the ball to create a seal, rather than forcing the ball against the seats. This design significantly reduces the operating torque and prevents seat wear in high-pressure applications.
Unsure about torque requirements for high-pressure service? Contact our engineers for detailed torque data and selection advice on A105N trunnion valves.
Detail Information
| Component | Description |
| Body Material | ASTM A105N (Forged Carbon Steel, Normalized) |
| Internal Trim | Usually Stainless Steel (304/316) or Carbon Steel with ENP (Electroless Nickel Plating) |
| Seat Material | Soft Seat (PTFE, RPTFE, DEVLON, PEEK) or Metal Seat (Tungsten Carbide/Stellite) |
| Operation | Lever, Gearbox, Pneumatic Actuator, or Electric Actuator |
| End Connections | Flanged (RF, RTJ) or Butt-Weld (BW) |
| Size Range | 2" to 48" (NPS 50 to NPS 1200) |
| Pressure Class | Class 150, 300, 600, 900, 1500, 2500 |
Specifications
A105N Trunnion Ball Valves are manufactured and tested according to international industry standards:
Design & Manufacture: API 6D / ASME B16.34 / ISO 14313
Face-to-Face Dimensions: ASME B16.10 (Standard dimensions for interchangeability)
End Flange Dimensions: ASME B16.5 (Up to 24") / ASME B16.47 (26" and above)
Butt-Weld Ends: ASME B16.25
Pressure Testing: API 6D / API 598 (Ensures zero leakage)
Fire Safety: API 607 / API 6FA (Ensures the valve remains sealed during a fire)
NACE Compliance: MR0175 (Optional, for sour/corrosive gas environments)
Features
Low Operating Torque: Because the ball is anchored by the trunnion, the fluid pressure does not push the ball into the downstream seat. This allows for smooth, easy operation even under maximum pressure.
Double Block and Bleed (DBB): Most API 6D trunnion valves provide a seal on both the upstream and downstream sides simultaneously. This allows the body cavity to be vented or drained while the valve is in the closed position.
Automatic Cavity Pressure Relief: If the pressure in the body cavity increases (e.g., due to thermal expansion), the seats are designed to push back slightly and vent the excess pressure back into the pipeline.
Anti-Static Design: Built-in springs ensure electrical continuity between the ball, stem, and body to prevent sparks from static electricity.
Blow-out Proof Stem: The stem is inserted from inside the body and is designed with a shoulder so that it cannot be blown out by internal pressure.
Emergency Sealant Injection: For valves 6" and larger, injection fittings are provided for the seats and stem. If the primary seal is damaged, emergency grease can be injected to stop a leak temporarily.
Fire-Safe Design: In the event of a fire that melts the soft seats, a secondary metal-to-metal seal is activated to prevent catastrophic leakage.
A105N Trunnion Mounted Ball Valve Factory
FAQ
What is a trunnion mounted ball valve used for?
Trunnion mounted ball valves are primarily used for high-pressure, large-diameter applications where reliable shut-off and easy operation are required.
Key uses include:
Oil & Gas Pipelines: Long-distance transmission of crude oil and natural gas.
Petrochemical Plants: Handling high-pressure fluids and gasses in refineries.
Critical Shut-off: Used where low operating torque is needed to allow for smaller, more efficient actuators.
Double Block and Bleed (DBB): Used in systems that require sealing on both sides of the valve to safely vent the body cavity.
What is the difference between a floating ball valve and a trunnion ball valve?
The fundamental difference between a floating ball valve and a trunnion mounted ball valve is how the ball is supported and how it creates a seal.
| Feature | Floating Ball Valve | Trunnion Mounted Ball Valve |
| Ball Support | Supported by the seats only | Anchored by stem and trunnion |
| Sealing Action | Ball moves toward the seat | Seats move toward the ball |
| Operating Torque | High (increases with pressure) | Low (stable across pressures) |
| Typical Size | Small (NPS 1/2 to 10) | Large (NPS 2 to 48+) |
| Pressure Class | Lower (usually up to Class 600) | High (up to Class 2500+) |
| DBB Feature | No | Yes |
| Cost | Lower | Higher |
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