Abstract: A butterfly valve having a valve body with a seat therein and a valve disc carried on a rotatable shaft such that the valve disc can be moved into and away from sealing engagement with the valve body seat is provided with a removable and replaceable seat member forming the valve body seat and a removable and replaceable sealing surface member is mounted on the valve disc which is sealingly engageable with the seat member when the valve disc is moved into sealing engagement with the valve body seat. The valve body seat preferably is sized to be press fit into a recess in the valve body and retained therein without additional fasteners. This butterfly valve can be used in a single, double or triple offset valve and the valve can be attached to a pipe in any conventional manner. The valve seat material and the sealing surface material may be solid metal, a resistant material such as nylon or Teflon.RTM. may have a metal insert or may have a high temperature insert such as graphite.

Abstract: An improved valve sealing arrangement where a sealing surface on the valve obturator presses against a compatibly arranged valve seat circumscribing a flow path to close the flow path, or alternately, the valve obturator having a through bore rotatable into position to align with the flow path. The improvement entails forming or cutting slots into the valve obturator behind upper and lower portions of the sealing surface to give localized flexibility to the upper and lower portions to match the flexibility of the middle region of the sealing surface which is located in front of the through bore.