Abstract: A sealing system for a plug-type unloader includes a bonnet having a guide bore with a stem reciprocably mounted within the guide bore. One end of the stem is affixed to a plug and the other end of the stem is connected to an actuator. A bellows member is positioned around the stem within the plug. The bellows member includes an expandable and contractible bellows having one end attached to the bonnet and the other end attached to the stem. Static seals are provided between one end of the bellows and the bonnet and the other end of the bellows and the stem. The bellows between the ends allows the bellows member to expand and contract as the stem reciprocates within the unloader. No dynamic seals are required. The plug of an unbalanced unloader includes a bore slidingly receiving an adapter around the bellows member to protect the bellows member from the pressure pulsations around the plug.

Abstract: A lift-turn valve actuator is provided for tapered plug valve and slip assemblies that accomplishes vertical movement of the plug and retraction of the slips from sealing engagement with the valve body prior to rotation of the plug member 90.degree. to its open position. The valve actuator assembly includes inner fitting inner and outer sleeve members each having cam slots formed therein with the cam follower of a valve actuating stem being engaged with both cam slots. Rotation of the outer sleeve member with respect to the static inner sleeve imparts initial vertical movement to the actuator stem, valve stem and valve plug for slip retraction as an initial component of movement followed by simultaneous rotational and upward movement of the plug member until the plug member has rotated 90.degree. to its open position.

Abstract: An annular valve seat having a resilient metal seal for use in a variety of types of valves provides positive control of fluid flow, with effective metal-to-metal sealing, long life and easy replacement of the seal. The metal seal is in the form of an annular ring comprising approximately one-quarter of a torus that cooperates with the valve's flow control element to establish a metal-to-metal fluid seal which is especially useful at relatively high temperatures. A first edge portion of the torus is held in position against a radial surface of the valve's body by a retainer ring which centers the torus about the flow control element. When the valve is closed the flow control element presses against the outside portion of the resilient metal torus forcing the free edge of the torus against a portion of the retainer ring so that the seal is loaded as a structural span supported at the ends by the valve's body and the retainer ring.