API 6D details three double block categories: DBB (double-block-and-bleed), DIB-1 (Double-isolation-and-bleed type 1), and DIB-2 (Double-isolation-and-bleed type 2). Trunnion Mounted Ball Valve Seat Designs Trunnion mounted API 6D ball valves have 2 seats that (one upstream, one downstream) can have a single (SPE) or double piston effect (DPE) seats. Single Piston Effect (PSE) Spring loaded […]