3.What is automatic body cavity relief ?

3.What is automatic body cavity relief ?

                                   

    When the body pressure going up un-normally as the unstable factor,the trunnion ball valve downstream seat will be pushed by un-normally pressure,and then release the un-normally pressure automatically,it does not damage to the sealing of upstream seat.The unnormal pressure which in the floating ball valve body will release the pressure into the upstream pipe directly,it doesn't damage to the sealing of the downstream seat.