API 6D pdf download
API 6D pdf download.Petro leum and natural gas industries— Pipeline transp ortation systems—Pipeline valves
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply: 3.1 ANSI rating class numerical pressure design class defined in ASME B1 6.5 and used for reference purposes NOTE The ANSI rating class is designated by the word “Class” followed by a number. 3.2 bi-directional valve valve designed for blocking the fluid in both downstream and upstream directions 3.3 bleed drain or vent 3.4 block valve gate, plug or ball valve that blocks flow into the downstream conduit when in the closed position NOTE Valves are either single- or double-seated, bi-directional or uni-directional. 3.5 breakaway thrust breakaway torque thrust or torque required for opening a valve with maximum pressure differential 3.6 by agreement agreed between manufacturer and purchaser 3.7 double-block-and-bleed (DBB) valve valve with two seating surfaces which, in the closed position, blocks flow from both valve ends when the cavity between the seating surfaces is vented through a bleed connection provided on the body cavity 3.8 drive train all parts of a valve drive between the operator and the obturator, including the obturator but excluding the operator 3.1 0 full-opening valve valve with an unobstructed opening capable of allowing a sphere or other internal device for the same nominal size as the valve to pass 3.1 1 handwheel wheel consisting of a rim connected to a hub, for example, by spokes, and used to operate manually a valve requiring multiple turns 3.1 2 locking device part or an arrangement of parts for securing a valve in the open and/or closed position 3.1 3 manual actuator manual operator wrench (lever) or handwheel with or without a gearbox 3.1 4 maximum pressure differential (MPD) maximum difference between the upstream and downstream pressure across the obturator at which the obturator may be operated 3.1 5 nominal pipe size (NPS) numerical inches designation of size which is common to components in piping systems of any one size NOTE The nominal pipe size is designated by the letters NPS followed by a number. 3.1 6 nominal pressure (PN) class numerical pressure design class as defined in ISO 7005-1 and used for reference purposes NOTE The nominal pressure (PN) class is designated by the abbreviation PN followed by a number. 3.1 7 nominal size (DN) numerical metric designation of size which is common to components in piping systems of any one size NOTE Nominal size is designated by the letters DN followed by a number. 3.1 8 obturator closure member part of a valve, such as a ball, clapper, disc, gate or plug, which is positioned in the flow stream to permit or block flow 3.20 position indicator device to show the position of the valve obturator 3.21 powered actuator powered operator electric, hydraulic or pneumatic device bolted or otherwise attached to the valve for powered opening and closing of the valve 3.22 pressure class numerical pressure design class expressed in accordance with either the nominal pressure (PN) class or the ANSI rating class NOTE In this International Standard, the pressure class is stated by the PN class followed by the ANSI rating class between brackets. 3.23 pressure-containing parts parts, such as bodies, bonnets, glands, stems, gaskets and bolting, designed to contain the pipeline fluid 3.24 pressure-controlling parts parts, such as seat and obturator, intended to block or permit the flow of fluids 3.25 process-wetted parts parts exposed directly to the pipeline fluid 3.26 reduced-opening valve valve with the opening through the obturator smaller than at the end connection(s) 3.27 seating surfaces contact surfaces of the obturator and seat which ensure valve sealing 3.28 stem part that connects the obturator to the operator and which may consist of one or more components
