CYLINDRISK KIKVENTIL

摘要

An improved cylindrical plug valve is of the type which includes a body having a cylindrical bore and a pair of axially aligned passages intersecting the bore and normal thereto. A cylindrical valve plug is rotatably disposed within the bore for movement between an opened and closed position for respectively aligning and misaligning a diametral port therethrough with the passages. Sealing rings around the plug above and below the port and passages prevent fluid from escaping from the interior of the plug valve. The improvement includes a pair of cup shaped recesses at opposite sides of the plug which are aligned with the passages when the valve is closed. Each recess is larger than the passage and has a substantially flat bottom and a peripheral side wall. A resiliently deformable sealing member inserted in the recess has a lip portion thereof extending around the peripheral side wall for surface contact therewith and is compressed between the bottom adjacent the peripheral side wall and an interior surface of the bore around the passage for sealed contact therebetween when the valve is closed. A support structure of the sealing member prevents any region of the lip portion from being displaced from the peripheral side wall. A plurality of openings through the sealing member communicate to the space between the bottom and the sealing member to prevent entrapment of fluid therein during closure.