- In a wide variety of cast materials covering carbon steel, alloy steel, and stainless steel.
- The ball of a trunnion mounted ball valve is fixed or constrained at two pivot points(upper stem and bottom stem).
- By using a bearing at the bottom stem(trunnion), only pivoting movement is allowed within the body cavity.
- The upstream seat is a floating seat and the process pressure pushes it against the ball’s sealing surface.
- The seat can also be pre-stressed during assembly, using seats that have a spring action. This design applies continuous pressure against a trunnion-mounted ball after the ball is installed, while the top-works apply a load to the entire closure member.
- Cast steel trunnion mounted ball valves are often soft seated and can attain a bubble-tight sealing.