Sealing assembly for ball valve with ball engageable secondary seal - which is in forced flow between two relatively movable piston elements with pressure faces.

摘要

The movable piston elements (7,12), which support the secondary ball seal (4) w.r.t.to the housing have pressure acting surfaces (9,14), one exposed to the pressure of the medium to be sealed, and the other one exposed to the pressure in the pressure chamber (6). Thus the secondary seal is under a pressure force, corresp.to the pressures acting on the pressure faces.The secondary seal pref. has at least one sealing element (10) made of graphite. Prestress members(18) may be provided for the sealing element. USE/ADVANTAGE - For ball valve sealing,with hermetic sealing against the housing.