Butterfly valve with eccentrically mounted flap - has expansible metal sealing ring held on flap by retaining ring

摘要

The flap (1) locates in a cylindrical conduit incorporating a ring (13) on its inner wall (12), the flap bearing on this ring to effect closure and aligning in a plane parallel to the conduit axis when open. To effect sealed closure the flap bears a metal ring, of elliptical shape conforming to the conduit ring (13), locating in a groove formed by a stepping of the flap periphery and a screw (5) fixed retaining ring (4). This metal ring is of greater internal dia. (Dr) than the groove dia. (Ds) and is thus, able to deform elastically and radially during clamping of the retaining ring. The metal ring is composed of three annular discs with the outer discs projecting beyond the inner disc.