KROHNE BM 70A EEx EN User Manual
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07/2010 - 4000662402 MA BM70x-Ex-AD-R02-en
3.3.2.
BM 70..-Ex with flange system V96 and WS Category 1 (Zone 0)
To simplify definition of the temperature class of the BM 70..-Ex level gauges with flange system V96,
the only reference temperature required is the temperature at the device flange. If the following
maximum values are not exceeded at the device flange, this will ensure that all other thermal limit
values at the device are also maintained.
The temperature class can be defined in one of two ways:
1)
Without measurement of the flange temperature
If the flange temperature is not known, the product temperature shall be taken as being the reference
temperature of the flange.
2)
With measurement of the flange temperature
For operating conditions which require Category 2 devices the product temperature may have higher
values than the flange temperature, taking in consideration the limits of the temperature classes.
The flange temperature shall be established under worst-case conditions (e.g. allowing
for the maximum possible product level and any additional insulation measures).
Standard-temperature version V96 and WS
Temperature Class
Maximum flange temperature
[°C]
T6
85
(1)
T5
100
(1)
T4 ... T1
130
Boundary conditions: Ambient temperature 55°C
(1)
observe application limitation for measuring devices
BM 702-Ex / BM 702 A-Ex
Where product temperature is > 100°C, a heat-resistant cable
with a continuous service temperature of 80°C is required.
Application limitation for measuring devices BM 702-Ex / BM 702 A-Ex
Temperature Class
Maximum flange
temperature [°C]
Maximum Ambient
temperature [°C]
T6
50
40
T5
90
40