Abstract: A top entry ball valve comprises a plug element having two curved sides and two inclined flat sides which contain the ball and two seats. A pair of cheek elements each having one curved side and one inclined flat side are disposed on either side of the plug element with the inclined flat side of each cheek element in contact with the inclined flat sides of the plug element. The valve body includes a cylindrical bore which is dimensioned to receive the plug element and the cheek elements, and which has an axis which is perpendicular to the axis of the inlet and outlet ports of the valve. The plug element is biased into the cylindrical bore, whereby the inclined sides of the plug element act against the inclined sides of the cheek elements to produce an axial force on the seats and the ball to form a leak-proof valve assembly.

Abstract: Disclosed is a butterfly valve having a seat, when viewed in cross-section, of generally U-shaped configuration, and an insert configured with appropriately shaped cooperating surfaces. The sealing effectiveness of the valve is enhanced by line pressure regardless of the direction of application of such pressure, the torque characteristics of the valve are relatively low, the ability to withstand temperature cycles is good, and the seat is restrained from destructive interference with the disc.

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: A valve seat insert is disclosed which is useful in a butterfly valve of the type disclosed and claimed in U.S. Pat. No. 3,608,861. In such valves, disc and sealing ring contact pressure is enhanced by fluid pressure in the fluid line regardless of the direction of fluid pressure. The valve seat mechanism provides a fulcrum to control deflection of the seat ring when the seat is pressurized from the stem side, and also, by means of an insert with a locking ridge, limits undesirable inward radial movement of the seat ring.