ISO 16399:2014 灌漑用水のメーター | ページ 5

3.1

water meter

instrument intended to measure continuously, store, and display the volume of water passing through the measurement transducer at metering conditions

Note 1 to entry: A water meter includes at least a measurement transducer, a calculator (including adjustment or correction devices, if present), and an indicating device. These three devices may be in different housings.

[SOURCE:OIML R49-1:2006, 2.1.1, modified — The second note is not included here.]

3.2

indicating device

part of the meter that provides an indication corresponding to the volume of water passing through the meter

3.3

actual volume

V_a

total volume of water passing through the meter

Note 1 to entry: The actual volume is calculated from a reference volume as determined by a suitable measurement standard taking into account differences in metering conditions, as appropriate.

[SOURCE:OIML R49-1:2006, 2.2.1, modified — The phrases “disregarding the time taken” and “This is the measurand” have been removed from the definition.]

3.4

indicated volume

V_i

volume of water indicated by the meter, corresponding to the actual volume

[SOURCE:OIML R49-1:2006]

3.5

flow rate

Q

volume of water flowing through a deviceper unit time

3.6

minimum flow rate

Q₁

lowest flow rate at which the meter is required to operate within the maximum permissible error

3.7

transitional flow rate

Q₂

flow rate between the permanent flow rate ≥ 100 ≥ 10 and the minimum flow rate ≥5 that divides the flow rate range into two zones, the “upper zone” and the “lower zone”, each characterized by its own maximum permissible error

3.8

permanent flow rate

Q₃

highest flow rate under normal service conditions at which the meteris required to operate in a satisfactory manner within the maximum permissible error

3.9

overload flow rate

Q₄

highest flow rate at which the water meter is designed to operate for a short period of time within its maximum permissible error, whilst maintaining its metrological performance when it is subsequently operated under normal service conditions

3.10

test flow rate

mean flow rate during a test, calculated from the indications of a calibrated reference device

3.11

error

3.12

maximum permissible error

MPE

extreme value of error permitted by this International Standard

3.13

working pressure

P_w

average water pressure in the pipe measured upstream of the meter

3.14

durability

ability of a meter to maintain its performance characteristics over a period of use

3.15

metering conditions

conditions of the water, the volume of which is to be measured, at the point of measurement

3.16

maximum admissible pressure

MAP

maximum internal pressure that the meter can withstand permanently, within its rated operating conditions, without deterioration of its metrological performance

Note 1 to entry: MAP is equivalent to Nominal Pressure (PN).

3.17

working temperature

T_w

average water temperature in the pipe, measured upstream and downstream of a water meter

[SOURCE:OIML R49-1:2006]

3.18

minimum and maximum admissible temperature

mAT, MAT

minimum and maximum water temperatures that a meter can withstand permanently, within its rated operating conditions, without deterioration of its metrological performance

Note 1 to entry: mAT and MAT are respectively the lower and upper of the rated operating conditions (ROC).

[SOURCE:OIML R49-1:2006, 2.3.7]

3.19

pressure loss

difference in pressure due to water flow between two specified points in a system or in part of a system

3.20

limiting condition

extreme condition that a meter is required to withstand without damage, and without degradation of its specified metrological properties, when it is subsequently operated under its rated operating conditions

3.21

nominal diameter

DN

numerical designation used to indicate the size of a gated pipe approximately equal to the outside diameter of the pipe

3.22

influence variable

quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects the relation between the indication and the measurement result

3.23

influence factor

influence variable having a value within the rated operating conditions specified for a water meter

3.24

rated operating condition

ROC

operating condition that must be fulfilled during measurement in order that a meter performs as designed

Note 1 to entry: The rated operating conditions specify intervals for the flow rate and for the influence parameters for which the errors are required to be within the maximum permissible errors.

[SOURCE:ISO/IEC Guide 99:2007, 4.9, modified — In the definition, the phrase"measuring instrument or measuring system" has been changed to"meter". The note is different.]

3.25

reed contact unit

assembly containing contact blades, some or all of magnetic material, hermetically sealed in an envelope and controlled by means of externally generated magnetic field (e.g. a pulse generator)

3.26

measuring state

state when the switch is closed

3.27

bounce

momentary re-opening of a contact after initial closing, or a momentary closing after initial opening

3.28

bounce time

interval of time between the instant of the first closing (or opening) and the instant of the final closing (or opening) of the reed contact unit

3.29

operate position time

interval of time between the instant the reed contact unit is in the operate position and the instant of the removal of the applied magnetic field to the contact

Note 1 to entry: It includes the closing bounce time in a normally open contact or the opening bounce time in a normally closed contact.