A trunnion mounted ball valve has the ball mechanically anchored at the top and bottom by trunnion bearings, which absorb pipeline pressure loads and keep the ball in a fixed position. Unlike floating ball valves — where the ball moves slightly to press against the downstream seat — trunnion mounted valves are better suited for high-pressure, large-diameter applications, as the ball does not shift under pressure, reducing seat wear and operating torque.

Double Block and Bleed (DBB) refers to a valve configuration that provides two independent seating surfaces (upstream and downstream) that block flow simultaneously, with a bleed port in between to safely vent or monitor the cavity pressure. This design is critical in oil, gas, and chemical applications where positive isolation is required for maintenance, pressure testing, or leak detection, meeting strict safety and regulatory standards.

Metal-to-metal sealing is preferred in applications involving high temperatures (above the limits of elastomers or PTFE), abrasive or erosive media, steam service, high-pressure hydrocarbon environments, and fire-safe requirements. While soft-seated valves offer zero-leakage at lower temperatures and pressures, metal-seated valves provide greater durability and long-term reliability in harsh process conditions where soft seats would degrade quickly.

An electric worm gear actuator converts the rotational motion of an electric motor through a worm gear reduction mechanism to produce the high torque needed to open or close the valve remotely. The worm gear design provides self-locking capability, preventing back-driving from pipeline forces. The manual override allows operators to actuate the valve by hand during power failures or emergency situations, ensuring continuous process control and safety even without electrical power.

Trunnion mounted ball valves with metal-to-metal sealing and DBB design are typically rated for pressure classes from ANSI Class 150 up to Class 2500 (PN 20 to PN 420), depending on body material and size. Temperature ratings generally range from cryogenic service (as low as -196°C / -320°F) to high-temperature service (up to 450°C / 850°F or higher) when constructed from appropriate alloy steels or stainless steels. Exact ratings depend on the specific material grade, size, and design standard applied.

Trunnion mounted ball valves for industrial use typically comply with API 6D (Pipeline and Piping Valves), API 6FA or API 607 (fire-safe testing), ASME B16.34 (valves — flanged, threaded, and welding end), and ISO 14313 (petroleum and natural gas industries). Additional certifications may include PED (Pressure Equipment Directive) for European markets, ATEX for use in explosive atmospheres, and NACE MR0175/ISO 15156 for sour service environments containing H2S.