Abstract: A fire-resistant valve 10 with a valve stem 40 mounted for linear motion through a valve stem bore 41 in the valve body 12 and connected to a valve element 20 by a connection means which effects movement of the valve element 20 between its valve open and its valve closed positions in response to axial linear motion of the valve stem 40. The valve includes a valve stem actuator 46 and a valve stem seal assembly comprising a primary seal in the form of an axially extensible and compressible metallic bellows 50 disposed in sleeved relation to the valve stem 40. The bellows is connected at one end by an annular weld 41 to the valve stem and at its other end by an annular weld 52 to the valve body in encircling relation to the valve stem and valve stem bore so as to effect a fluid-tight, gas-tight seal therebetween. A packing structure mounted in the annulus between the valve stem and wall of the valve stem bore provides a secondary valve stem seal.

Abstract: A segmented ball valve has a rotatably mounted segmented ball valve element positioned to rotate eccentrically in a valve body with respect to three valve body sealing elements about the sealing opening for the valve body. The sealing elements include a compression seal of a flexible sealing element operative at one angular closure position of the ball valve element, a metal-to-metal seal with a flexible metal element operative in a second angular closure position and a metal-to-metal compression seal operative in a third angular closure position.