BUTTERFLY VALVE

摘要

An improved butterfly valve is provided herein. It includes a valve body, a valve seat, a rotatably supported valve stem, a disk-like valve member and ring-shaped seal means. A hollow cylindrical portion if formed as the valve member by means of which the valve member is mounted on the valve stem. The seat face of the valve seat has a central raised portion. One annular antifriction member having a small frictional resistance and durability is interposed between each end surface of the cylindrical portion of the valve member and the inner surface of the valve seat opposed thereto. In this way a butterfly valve is provided which is easy to operate for both opening and closing and provides almost perfect sealing of the fluid flow by providing plastics materials having a small frictional resistance and durability on the area limited to the constant contact part of the valve seat and the valve member.