Trunnion Mounted Full Welded Ball Valve

Trunnion Mounted Full Welded Ball Valve – Technical Overview

A trunnion mounted full welded ball valve is a high-performance pipeline valve designed for long-term, maintenance-free service in high-pressure and large-diameter applications. The full welded body construction eliminates body joints and bolting, ensuring zero external leakage, improved structural strength, and enhanced resistance to pipeline stresses.

In a trunnion mounted design, the ball is supported at both the top and bottom by trunnion bearings, significantly reducing operating torque and enabling smooth operation under high differential pressures. This makes it an ideal solution for oil & gas transmission, natural gas distribution, petrochemical processing, and buried pipeline systems.

Key Operating Environments

• Long-Distance Natural Gas Pipelines – Minimizes leakage risk and maintenance in remote areas.

• Oil & Gas Gathering and Transmission Systems – Handles high pressure and large flow rates with ease.

• Underground and Subsea Pipelines – Fully welded construction resists corrosion and environmental impact.

• Refineries and Petrochemical Plants – Ensures safe isolation of hydrocarbons and process media.

• District Heating Networks – Reliable shutoff in hot water and steam service.

Material Selection & Performance Benefits

• Carbon Steel (A105, API 5L Grades) – High strength and cost-effective for standard oil & gas service.

• Low-Temperature Carbon Steel (LCC, LCB) – Maintains ductility and toughness at low ambient temperatures.

• Stainless Steel (CF8M, CF3M) – Excellent corrosion resistance in aggressive process media.

• Special Alloys (Duplex, Inconel, Monel) – Designed for severe corrosion and high-pressure environments.

Seats can be soft-seated (PTFE, RPTFE, PEEK) for tight sealing or metal-seated for high temperature and abrasive media.

Design Features

• Full Welded Body – No body bolts, reducing leakage points and extending service life.

• Trunnion Mounted Ball – Reduced operating torque, stable sealing under high pressure.

• Double Block and Bleed (DBB) Capability – Ensures safety during maintenance by isolating and venting pressure.

• Emergency Sealant Injection – Allows sealing in case of seat damage without shutting down the line.

• Anti-Blowout Stem & Fire-Safe Design – In compliance with API 6D, API 607, and ISO fire-safe standards.

• Full Bore or Reduced Bore Options – Maintains flow efficiency or reduces valve size to meet system requirements.

Advantages in Pipeline Applications

• Zero External Leakage – Fully welded body ensures long-term sealing integrity.

• Buried Installation Friendly – Requires minimal above-ground maintenance, reducing operational cost.

• High Pressure & Large Diameter Capability – Ideal for critical energy infrastructure.

• Long Service Life – Resistant to vibration, temperature fluctuations, and pipeline stress.

• International Compliance – Meets API 6D, ISO 14313, and relevant pipeline valve standards.

A trunnion mounted full welded ball valve combines the low-torque benefits of trunnion support with the durability and leak prevention of a fully welded body. Its robust design makes it the preferred choice for critical, long-distance, and high-pressure pipeline operations where safety, efficiency, and longevity are essential.