Structural features of DBB trunnion ball valve

Double cut-off and relief design of DBB trunnion ball valve

(1). Double blocking and venting function

The trunnion ball valve generally adopts the ball front seat sealing structure. The two valve seats 

of the trunnion ball valve can independently cut off the medium at the inlet end to realize the 

double-break function. When the ball valve is closed, even if the inlet and outlet ends of the valve 

are pressurized at the same time, the valve The middle cavity and the channels at both ends can 

also be blocked from each other, and the remaining medium in the middle cavity can be 

discharged through the relief valve.

(2). Automatic pressure relief of the valve cavity

When the liquid medium in the middle cavity of the valve vaporizes due to the increase in 

temperature, causing the pressure in the middle cavity to increase abnormally, the medium in the 

middle cavity can rely on its own force to push the valve seat and automatically release the 

pressure, thereby ensuring the safety of the valve .