Kamstrup ULTRAFLOW 34 DN15-125, Техническое описание, Страница: 68 / 86

ULTRAFLOW® 54/34
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Kamstrup A/S · Technical description · 5512-2464_A1_GB_08.2019
8.12 Accuracy
ULTRAFLOW® has been developed as a volume flow rate sensor for energy meters according to EN 1434. The tolerances
permitted for flow sensors according to EN 1434 with a dynamic range of 100:1 (q
p
:q
i
) and q
p
1,5 m
3
/h are shown in Figure
58 . The tolerances are defined for class 2 and class 3 with following formulas:
Class 2:
± (2 + 0,02 ∙
𝑞
𝑝
𝑞
) %
, however max ±5 %
Class 3:
± (3 + 0,05 ∙
𝑞
𝑝
𝑞
) %
, however max ±5 %
EN 1434 defines the following dynamic ranges (q
p
:q
i
): 10:1, 25:1, 50:1, 100:1 and 250:1.
In connection with accuracies, the range from q
p
to q
s
is defined as max flow short-term where tolerances are adhered
to. There are no requirements to the relation between q
p
and q
s
. See Table 1 for information on q
s
for ULTRAFLOW®.
To render probable that the sensors meet the tolerance requirements, EN 1434-5 specifies calibration requirements in
connection with verification of sensors. It is required that flow sensors are tested at the following 3 points:
q
i
…1.1 x q
i
, 0.1 x q
p
…0.11 x q
p
and 0.9 x q
p
…q
p
During test, the water temperature must be 50 °C ±5 °C for ULTRAFLOW® as a heat meter.
For ULTRAFLOW® as a cooling meter, the water temperature must be 15 °C ±5 °C.
Further requirements are that the tolerance of the equipment used to perform the test must be less than 1/5 MPE
(Maximum Permissible Error) to permit the acceptance limit to be equal to MPE. If the equipment does not observe 1/5
MPE, the acceptance limit must be reduced by the tolerance of the equipment.
ULTRAFLOW® will typically do better than half of the permitted tolerance according to EN 1434 class 2.
Note: For further information regarding allowable test conditions such as water temperature and flow of the individual
ULTRAFLOW®, see the approval of ULTRAFLOW® (see paragraph
11 Approvals ).