ISO 14313:2007 石油および天然ガス産業—パイプライン輸送システム—パイプラインバルブ | ページ 6

4.1

ASME rating class

numerical pressure design class defined in ASME B16.34 and used for reference purposes

Note 1 to entry: The ASME rating class is designated by the word “class” followed by a number.

4.2

bi-directional valve

valve designed for blocking the fluid in both downstream and upstream directions

4.3

bleed

drain or vent

4.4

block valve

gate, plug or ball valve that blocks flow into the downstream conduit when in the closed position

Note 1 to entry: Valves are either single- or double-seated, bi-directional or uni-directional.

4.5

breakaway thrust

breakaway torque

maximum thrust or torque required to operate a valve at maximum pressure differential

4.6

by agreement

agreed between manufacturer and purchaser

4.7

double-block-and-bleed valve

DBB

single valve with two seating surfaces that, in the closed position, provides a seal against pressure from both ends of the valve with a means of venting/bleeding the cavity between the seating surfaces

Note 1 to entry: This valve does not provide positive double isolation when only one side is under pressure. See double-isolation-and-bleed valve (4.8) .

4.8

double-isolation-and-bleed valve

DIB

single valve with two seating surfaces, each of which, in the closed position, provides a seal against pressure from a single source, with a means of venting/bleeding the cavity between the seating surfaces

Note 1 to entry: This feature can be provided in one direction or in both directions.

4.9

drive train

all parts of a valve drive between the operator and the obturator, including the obturator but excluding the operator

4.10

flow coefficient

K_v

volumetric flow rate of water at a temperature between 5 °C (40 °F) and 40 °C (104 °F) passing through a valve and resulting in a pressure loss of 0,1 MPa (1 bar; 14.5 psi)

Note 1 to entry:K_v is expressed in SI units of cubic metres per hour.

4.11

full-opening valve

valve with an unobstructed opening, not smaller than the internal bore of the end connections

4.12

handwheel

wheel consisting of a rim connected to a hub, for example by spokes, and used to manually operate a valve requiring multiple turns

4.13

locking device

part or an arrangement of parts for securing a valve in the open and/or closed position

4.14

manual actuator

manual operator

wrench (lever) or hand-wheel with or without a gearbox

4.15

maximum pressure differential

MPD

maximum difference between the upstream and downstream pressure across the obturator at which the obturator may be operated

4.16

nominal pipe size

NPS

numerical imperial designation of size which is common to components in piping systems of any one size

Note 1 to entry: Nominal pipe size is designated by the abbreviation “NPS” followed by a number.

4.17

nominal pressure class

PN

numerical pressure design class as defined in ISO 7268 and used for reference purposes

Note 1 to entry: Nominal pressure (PN) class is designated by the abbreviation “PN” followed by a number.

4.18

nominal size

DN

numerical metric designation of size that is common to components in piping systems of any one size

Note 1 to entry: Nominal size is designated by the abbreviation “DN” followed by a number.

4.19

obturator

closure member

part of a valve, such as a ball, clapper, disc, gate or plug that is positioned in the flow stream to permit or prevent flow

4.20

operator

device (or assembly) for opening or closing a valve

4.21

packing gland

component used to compress the stem packing

4.22

position indicator

device to show the position of the valve obturator

4.23

piggability

capability of a valve to permit the unrestricted passage of a pig

4.24

powered actuator

powered operator

electric, hydraulic or pneumatic device bolted or otherwise attached to the valve for powered opening and closing of the valve

4.25

pressure class

numerical pressure design class expressed in accordance with either the nominal pressure (PN) class or the ASME rating class

Note 1 to entry: In this International Standard, the pressure class is stated by the PN class followed by the ASME rating class between brackets.

4.26

pressure-containing parts

parts, whose failure to function as intended results in a release of contained fluid into the environment

4.27

pressure-controlling parts

parts, such as seat and obturator, intended to prevent or permit the flow of fluids

4.28

process-wetted parts

parts exposed directly to the pipeline fluid

4.29

reduced-opening valve

valve with the opening through the obturator smaller than at the end connection(s)

4.30

seating surfaces

contact surfaces of the obturator and seat which ensure valve sealing

4.31

stem

part that connects the obturator to the operator and which can consist of one or more components

4.32

stem extension assembly

assembly consisting of the stem extension and the stem extension housing

4.33

support ribs or legs

metal structure that provides a stable footing when the valve is set on a fixed base

4.34

through-conduit valve

valve with an unobstructed and continuous cylindrical opening

4.35

uni-directional valve

valve designed for blocking the flow in one direction only

4.36

unless otherwise agreed

unless the manufacturer and purchaser agree on a deviation

4.37

unless otherwise specified

unless the purchaser specifies otherwise

4.38

venturi plug valve

valve with a substantially reduced opening through the plug and a smooth transition from each full-opening end to the reduced opening