Trunnion Ball Valve

Product Overview

The trunnion ball valve is engineered for demanding applications in oil and gas, petrochemical, and other high-pressure industries. Its unique design features a ball that is supported by trunnions (short shafts) at the top and bottom, which reduces seat load and operating torque while maintaining bubble-tight sealing even at high pressures up to Class 2500.

These valves are available in various configurations including full bore and reduced bore, with fire-safe design options, and can be operated manually, pneumatically, or electrically. Materials range from carbon steel and stainless steel to special alloys for corrosive environments.

PTFE Seated Ball Valve

Metal Seated Ball Valve

Features & Benefits

Trunnion ball valves offer significant advantages over floating ball valves in high-pressure and critical applications. Their robust design ensures reliable performance in the most demanding industrial environments.

1

Lower Operating Torque

The trunnion-mounted ball design reduces friction, requiring less torque to operate even at high pressures, which extends actuator life.

2

High-Pressure Capability

Designed for pressures up to Class 2500 (ANSI) or higher, making them ideal for critical high-pressure applications.

3

Bubble-Tight Sealing

Spring-loaded seats ensure positive sealing in both directions, even after long periods of inactivity.

4

Fire-Safe Design

Optional fire-safe construction with secondary metal-to-metal sealing in case of seat destruction during fire.

5

Reduced Seat Wear

The trunnion support minimizes seat load, reducing wear and extending service life in high-cycle applications.

6

Dual Block and Bleed

Can be designed to provide double block and bleed functionality for isolation and maintenance safety.

Application Fields

Trunnion ball valves are essential components in industries where reliability under high pressure is critical. Their robust construction makes them suitable for a wide range of demanding applications:

• Oil and Gas Transmission: Mainline and station piping systems for crude oil, natural gas, and refined products.

• Petrochemical Plants: High-pressure processing units, reactor feed systems, and product distribution.

• Power Generation: Steam lines, feedwater systems, and auxiliary services in thermal power plants.

• Chemical Processing: Handling corrosive and hazardous chemicals at elevated pressures.

• Pipelines: Long-distance transmission lines for liquids and gases with pigging capability (full bore design).

• Offshore Platforms: Subsea and topside applications in marine environments with space and weight constraints.

Design & Operating Principle

Unlike floating ball valves where the ball is free to move, trunnion ball valves feature a ball that is fixed in position by trunnions (short shafts) at the top and bottom. This design provides several key advantages:

• Fixed Ball Position: The ball remains centered regardless of pressure, preventing deformation and ensuring consistent sealing.

• Spring-Loaded Seats: Seats are pressed against the ball by springs and/or line pressure, creating a bidirectional seal.

• Reduced Operating Torque: Since the ball doesn't press against the downstream seat, operating torque is significantly lower than floating designs.

• Seat Replacement: Many trunnion ball valves allow seat replacement under pressure, reducing maintenance downtime.

Trunnion ball valves are available in various configurations including top-entry (single-piece body) and side-entry (split-body) designs. Top-entry valves allow internal maintenance without removing the valve from the pipeline, while side-entry designs offer easier assembly and disassembly.

Side Entry Design

Allows in-line maintenance without valve removal

Top Entry Design

Easier assembly and disassembly for maintenance

Valve Construction & Components

Shield^TM Trunnion ball valves feature advanced engineering for superior performance in demanding applications. Below is a detailed breakdown of the key components that ensure reliability and longevity.

A BODY: Investment cast from high-grade materials with full radiographic testing for defect-free construction.

B BALL: Precision machined and hard chrome plated or stellited for wear resistance and low friction.

C TRUNNION SHAFTS: Upper and lower shafts that support the ball, reducing operating torque and seat wear.

D SEATS: Spring-loaded PTFE or reinforced thermoplastic seats with secondary metal sealing for fire-safe applications.

E STEM: Blowout-proof design with anti-static device for safe operation in hazardous areas.

F SEALING SYSTEM: Multiple stem seals including primary, secondary, and fire-safe graphite packing.

G BOLTING: High-strength bolting with controlled torque for uniform sealing pressure.

H INJECTION PORTS: For sealant injection to maintain sealing performance or provide emergency sealing.

Our trunnion ball valves comply with international standards including API 6D, API 607/6FA (fire-safe), ASME B16.34, and ISO 17292. They are available in sizes from 2" to 60" and pressure classes from 150 to 2500, with various end connections including flanged, butt-weld, and socket-weld.

Technical Drawings & Resources

Download detailed technical drawings, product brochures, and specifications for our valves. These resources provide comprehensive information for engineers, procurement specialists, and maintenance teams.

?Technical Drawings

Complete set of detailed engineering drawings in PDF format for easy integration into your design projects. Includes dimensional drawings, assembly diagrams, and installation guidelines.

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