Fire safe design
1.Stem leakage prevention, before fire happen, the leakage from the valve stem is prevented by O-ring seals and gasket. When fire happens, the O-rings, gasket has been destroyed. The graphite stem packing still can be prevents external leakage.
2.Seat leakage prevention, after the soft sealing materials has been destroyed by fire, the seat pre-loaded spring comes into contact with the ball to block the leakage, also a graphite seat gasket is compressed by the spring to prevent leakage between the valve body and seat.
Anti- Blowout Stem design
Formen ball valves stem is made separately from the ball. The lower end of the stem is designed with an intergral shoulder to be blowout-proof.
Its a standard feature of antistatic device for Formen ball valve. A spring-loaded pin assures the electrical continuity between the ball, stem and body to avoid sparking during the turning of the stem to open and closed the valve.