1.What is anti-fire safe design ?

1.What is anti-fire safe design ?

                                  

     When the trunnion  ball  valve be used normally,its sealed by seat and ball surface,seat retainer  sealed  by O-ring and body,this is soft sealed  and  reliable  sealing . When the seat and O-ring are burnt,the seat retainer and body will be sealed by expanded graphite.Thus act anti-fire safepurpose .