A trunnion ball valve is a critical solution for controlling the flow of liquids and gases in high-pressure industrial pipelines. Whether you’re in oil & gas, petrochemical, or water treatment, choosing the right valve can mean the difference between safe operations and costly downtime.
In this guide, we’ll explain what a trunnion mounted ball valve is, discuss its design and applications, and help you choose the right valve based on your system’s needs. We’ll also highlight Gowin’s API 6D trunnion mounted ball valves, including 3 piece trunnion ball valves and fully welded trunnion ball valves, trusted globally for their quality and safety.
What Is a Trunnion Ball Valve?
If you’re wondering, “What is a trunnion mounted ball valve?”, here’s a simple answer: it’s a type of ball valve trunnion type, where the ball is anchored at both ends by trunnions (mechanical shafts). Unlike floating ball valves, where the ball “floats” under pressure, the trunnion ball valve design fixes the ball in place, and spring-loaded seats move to form a tight seal.
This trunnion mounted ball valve design makes it ideal for high-pressure and large-diameter pipelines, offering better sealing, reduced torque, and longer life. Gowin’s forged steel trunnion ball valves are especially suited for these demanding environments.
Here’s the key structure of trunnion ball valves:
- Trunnion-mounted ball: The ball is anchored by shafts (trunnions) that keep it stable. Unlike floating designs, the ball doesn’t rely on line pressure to stay in place, which means less wear and better sealing performance.
- Seats: Spring-loaded or pressure-assisted seats push against the ball for reliable, tight sealing — even at low pressures. Metal seated trunnion ball valves are also available for abrasive or high-temperature media.
- Stem: The stem connects the actuator or handle to the ball. High-quality trunnion valves like Gowin’s 3PC design include an anti-blowout stem, a critical safety feature to prevent stem ejection under pressure.
- Body: 3PC (Three-Piece Body) is easy to dismantle for cleaning, maintenance, or seat replacement — a huge advantage for industrial plants that can’t afford long shutdowns. Fully Welded Body is sealed shut to prevent any leakage. Ideal for buried pipelines where valves are not easily accessible.
- Sealing system: O-rings, gaskets, and fire-safe seals ensure tight shutoff. Gowin’s API 607-certified valves are fireproof, maintaining seal integrity even during fire emergencies.
The three-piece design of Gowin’s valve also allows for easy disassembly, making maintenance cost-effective and efficient—ideal for industries where downtime is expensive.
Where Are Trunnion Ball Valves Used?
Given their robust design, trunnion ball valves are essential in a wide range of industries where safety, efficiency, and durability are key.
- Oil & Gas Pipelines: From upstream extraction to midstream transport and downstream refining, trunnion valves control crude oil, natural gas, and refined products safely and efficiently.
- Petrochemical Plants: Handling aggressive chemicals and corrosive fluids requires tight shutoff and high corrosion resistance — trunnion valves are perfect here.
- Power Plants: Used in steam, water, and cooling systems to manage flow in high-pressure, high-temperature environments.
- Water Treatment: For controlling treated and raw water, ensuring no leakage or contamination.
- Industrial Processing: Handling various liquids, gases, and slurries under varying pressures.
These industries require valves that won’t fail under pressure or fire conditions, which is why if your operation requires zero leakage and high reliability, Gowin’s API 607 fireproof-certified trunnion ball valves are a trusted choice.
Fully Welded Trunnion Ball Valve: When Is It the Right Choice?
A fully welded trunnion ball valve has no bolted body parts, reducing potential leak paths. It is permanently sealed, making it ideal for:
- Buried and underground pipelines (e.g., gas transmission lines)
- Subsea applications
- City gas distribution networks
Because maintenance access is limited in these settings, the fully welded valve’s leak-free, maintenance-free design becomes a huge advantage.
Why Certifications Matter
When dealing with high-risk applications like oil & gas or petrochemical processes, certified valves are essential to meet safety and regulatory demands. Here are the key certifications to look for:
API 607 (Fireproof Certification):
- Ensures valve maintains sealing and structural integrity during and after exposure to fire.
- Essential for gas and flammable liquid pipelines.
- Gowin’s 3PC Trunnion Ball Valve is fully API 607 certified.
API 6D (Pipeline Valve Certification):
- Covers design, production, and testing of pipeline valves for safe and efficient operation.
- Ensures high quality, durability, and safety compliance in pipeline transport systems.
- Gowin’s valves meet API 6D standards, making them trusted worldwide.
How to Choose the Right Trunnion Ball Valve
Picking the right trunnion ball valve is more than just selecting a size. It’s about making sure the valve works safely and efficiently for the long haul. Whether you’re handling gas, oil, chemicals, or water, getting this decision right can save you from leaks, failures, and costly downtime.
Here’s what to look at before buying:
- Pressure and temperature ratings: Make sure the valve is rated for the pressures and temperatures your system runs on. If you’re working in high-pressure gas pipelines or steam lines, a low-rated valve simply won’t hold up. Always check the valve’s pressure class (like ANSI 150, 300, or higher) and its operating temperature limits. High-pressure, high-temp environments need valves built to handle that stress.
- Material selection: Choose a material that’s compatible with what’s flowing through the pipeline. For oil, natural gas, or other hydrocarbons, carbon steel is a common choice. But if you’re dealing with corrosive chemicals, salty environments, or sour gas (H₂S), you’ll need something tougher, like stainless steel or duplex steel. Some applications may even call for exotic alloys. Using the wrong material can cause corrosion or cracking over time.
- Certifications (API 607 and API 6D): Don’t compromise on safety—make sure your valve is certified to handle pipeline conditions. API 607 means the valve is fireproof, able to seal even during a fire. API 6D ensures the valve meets rigorous standards for pipeline operation, including strength, sealing, and safety. Gowin’s 3PC Trunnion Ball Valve carries both these certifications, so it’s trusted worldwide in critical applications.
- Size and bore type: Think about flow needs when picking the valve size and bore. If you need to maintain full flow through the pipeline, a full bore valve is your best option—it prevents pressure drops and makes pigging (pipeline cleaning) possible. If flow capacity isn’t as critical, a reduced bore valve can save cost without hurting performance.
- End connections: Match the valve’s ends to how your pipeline is set up. Flanged ends are popular because they’re easy to install and remove, making maintenance simpler. If you’re dealing with high-pressure or underground pipelines, butt-weld ends are often preferred for a leak-proof, permanent connection. Choose what’s compatible with the rest of your system.
Final Thoughts: Why Choose Gowin?
When safety, durability, and compliance are critical, Gowin’s trunnion ball valves stand out. With API 607 (fireproof) and API 6D (pipeline) certifications, our 3PC Trunnion Ball Valve offers unmatched performance in high-pressure and hazardous environments.
Plus, our fully welded trunnion ball valve is the top choice for buried pipelines needing maintenance-free operation for years. Contact us today for more info!
Resources:
Understanding Trunnion Ball Valves: A Comprehensive Guide
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