China Forged Steel Trunnion-Mounted DBB Ball Valve Suppliers - Durable Metal-Seated Design from Trusted Factory

A True Double Block & Bleed (DBB) design means the valve features two independent seating surfaces — one upstream and one downstream — that can each independently isolate pressure. The bleed function allows safe venting of trapped cavity pressure between the two seats, providing a higher level of safety and leak prevention compared to single-seat designs.

Metal-to-metal hard seated valves are specifically engineered for extreme service environments where soft seats would degrade or fail. Hardfaced metal seats resist high temperatures, abrasive media, erosive particles, and high-pressure conditions, making them ideal for oil refining, gas processing, and power generation applications where durability and long service life are critical.

In a trunnion-mounted valve, the ball is mechanically supported at both the top and bottom by trunnions (fixed pivot points), meaning the ball does not shift under pressure. This significantly reduces the operating torque required to actuate the valve and ensures consistent sealing performance at high pressures. Floating ball valves, by contrast, rely on line pressure to push the ball against the downstream seat, which can increase torque requirements at higher pressures.

A fire-safe valve is designed and tested to maintain a minimum level of sealing integrity even after exposure to fire or extreme heat. In the event of a fire, soft seal materials may burn away, but a fire-safe metal-seated valve will still provide a secondary metal-to-metal seal to prevent dangerous leakage. This feature is required by industry standards such as API 607 and API 6FA for critical pipeline and process safety applications.

Trunnion-mounted metal seated ball valves are widely used in upstream and downstream oil and gas pipelines, gas processing plants, petrochemical and refinery facilities, power generation systems, subsea installations, and any high-pressure or high-temperature process environment where reliable shutoff and long-term sealing performance are required under severe service conditions.

Forged steel bodies offer superior mechanical strength, a denser grain structure, and fewer internal defects compared to cast steel. This makes them more resistant to pressure surges, mechanical stress, and fatigue cracking in demanding service environments. Forged steel is the preferred material for high-pressure, high-temperature, and critical safety applications in the oil, gas, and chemical industries due to its enhanced structural reliability and longer service life.