Abstract: An annular valve seat is fitted in a rotary fluid control valve of the butterfly type. The seat consists of a radially outer tail portion, a radilly intermediate metal support portion in the shape of an S and a radially inner metal seal portion having a metal sealing surface in the form of an annular semi-torus. The seal portion includes structure for retaining an elastomeric sealing insert. The valve seat is inserted in a groove between the valve body and an insert, with a small space existing between the axial sides of the groove and the axial sides of the S-shaped intermediate portion. The intermediate portion accordingly permits limited flexure in response to pressure stresses on the valve seat, but the flexure is limited by contact with the walls of the groove. The metal and elastomeric sealing surfaces provide leak-free sealing with an extending life.

Abstract: Disclosed is a fire-tested butterfly valve having an annular resilient seat member and an annular, flexible metal seat member, both held in place in a valve housing by being clamped between cooperating surfaces of the valve housing and a valve seat retaining ring insert. In a first embodiment, a fusible washer with a lower destruction temperature than that of the annular resilient seat is positioned between the resilient seat and the metal seat. In a second embodiment, an integrally formed protrusion on the annular resilient seat contacts the metal seat. In both embodiments, the metal seat is held out of contact with the butterfly disc until exposure to a fire melts the fusible washer or the seat protrusion, at which time the metal seat comes into contact with the disc to establish a secondary, metal-to-metal, fire resistant seal.

Abstract: Disclosed is a lock for a valve having a stem which by rotation controls the opening and closing of the valve. The lock essentially comprises a housing having a first opening therein to receive the stem and a second opening; a locking member is disposed in the second opening and comprises a terminal portion which in its closed position contacts the stem and prevents the stem from rotating, a middle portion connected to the terminal portion and having a periphery substantially equal to the greatest periphery of the second opening, and an end portion connected to the middle portion and having a periphery less than the greatest periphery of the second opening.