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China Suppliers Factory Twin Ball DBB Trunnion-Mounted Ball Valve with Worm Gear for Leak-Free High-Pressure Solutions
Product Highlights
Key Features
Twin Ball DBB Design
Dual trunnion-mounted balls with central bleed provide double block-and-bleed isolation, safe pressure release, and leakage monitoring for high-risk media.
Enhanced Safety Features
Engineered with fire-safe, anti-static, and anti-blowout stem design, ensuring reliable operation under high-pressure and hazardous conditions.
Heavy-Duty Body & Support
Forged steel body with robust trunnion support handles high-pressure, high-flow applications, delivering long-term durability and stable performance.
Versatile Control & Easy Operation
Twin balls can be operated independently or synchronously, supporting dual-line flow, merging, or emergency shut-off, while worm-gear drive reduces torque for easier manual control.
Frequently Asked Questions
What is a Twin Ball DBB (Double Block and Bleed) valve?
A Twin Ball DBB valve incorporates two trunnion-mounted ball valves in a single body with a central bleed port between them. This design allows operators to isolate a section of pipeline from both upstream and downstream pressure simultaneously, and then vent or monitor the cavity between the two balls — providing double block-and-bleed isolation for maximum safety with high-risk media.
What does "fire-safe" design mean for a ball valve?
A fire-safe ball valve is designed and tested to maintain a reliable seal even if the soft polymer seats and seals are destroyed by fire. The metal-to-metal seating surfaces take over to prevent hazardous media from leaking, meeting industry standards such as API 607 or BS 6755 Part 2. This is critical in oil, gas, and petrochemical applications where fire resistance is mandatory.
Why is a forged steel body preferred over a cast steel body?
Forged steel bodies have a denser, more uniform grain structure compared to cast steel, resulting in higher tensile strength, improved impact resistance, and better tolerance for pressure surges. This makes forged steel valves particularly suited for high-pressure, high-temperature, and demanding industrial environments where long-term reliability is essential.
Can the two ball valves be operated independently?
Yes. The twin ball design allows each ball to be operated independently or synchronously depending on the process requirements. Independent operation supports dual-line flow management, flow merging, or individual line shut-off, while synchronous operation enables simultaneous emergency shut-off of both lines. The worm-gear drive further reduces the required torque, making manual control efficient even under high-pressure conditions.
What is an anti-blowout stem and why is it important?
An anti-blowout stem is a safety feature where the valve stem is designed with a shoulder or retaining mechanism that prevents it from being ejected from the valve body if packing or gland pressure is lost — for example, due to severe over-pressure conditions. This is a critical safety requirement in hazardous process environments to protect personnel and equipment from catastrophic stem ejection incidents.
In what industries are Twin Ball DBB valves commonly used?
Twin Ball DBB valves are widely used in oil and gas production and transmission, petrochemical and chemical processing, offshore platforms, LNG terminals, and industrial pipelines handling hazardous or toxic media. Their ability to provide double isolation and bleed monitoring makes them the preferred choice wherever safety regulations demand positive pipeline isolation and pressure verification before maintenance or inspection.