KROHNE BM 70 M - Manual (Page 21)

BM 70 M 21
Antenna heating/cooling device
(> DN150/6") Purging device
(> DN100)
Hazardous-duty systems:
In Zone 0, the temperature of the heating
system and antenna may not exceed 80 % of
the ignition temperature of the stored
material.
Continuous monitoring shall ensure, and
operational inspections shall verify, that the
80% level of the ignition temperature stated
in Point 1 above is not exceeded. If a liquid is used for purging, this may interfere
with the functioning of the BM 70 M during the
process. Continuous purging with gas is not a
problem as it does not interfere with
measurements.
The purge connection is closed off by the
manufacturers with a ¼" screw. When this screw
is removed to connect up a purging system, the
operator is responsible for ensuring conformity
with "Ex" requirements in connection with the
purging circuit (e.g. fitting a flame trap).
6.1.8 Ultimate installation on the tank
After carefully positioning the BM 70 M on the tank fitting flange (not forgetting the gasket), align
the BM 70 M and the gasket.
Insert stud bolts and tighten nuts slightly (by hand). (These items not included with supply).
Tighten down stud bolts and nuts firmly. The torque is dependent on the strength properties of the
stud bolts and the pressure rating of the tank.
6.2 Ambient conditions
6.2.1 Hazardous locations
BM 70 M Ex is suitable for use in hazardous locations of the following zones: 0, 1, 2
Temperature classes T6...T2; danger groups: IIA...IIC
Further information see Section 10
6.2.2 Ambient temperature of signal converter
BM 70 M with horn antenna or Wave-Guide: -20 ... +55°C (-4 ... +131°F)
A BM 70 sunshade should be fitted if the converter is located in the open with the likelihood of
strong exposure to sunlight (see Section 6.1.9).
6.2.3 Flange temperature
Horn antenna, Wave-Guide (T
amb
* ≤ 50°C): -30 ... +130°C (-22 ... +266°F
Horn antenna, Wave-Guide (T
amb
* ≤ 55°C): -30 ... +120°C (-22 ... +248°F
High-temperature version with distance piece and
FFKM gasket (Kalrez 4079 or Parofluor V3819-
75) -30 ... +250°C (-22 ... +482°F) **
Kalrez 2035 gasket -30 ... +210°C (-22 ... +410°F)
Viton gasket -30 ... +200°C (-22 ... +392°F)
FEP-sheathed gasket -30 ... +200°C (-22 ... +392°F)
* T
amb
is the ambient temperature of the signal converter
** Safety limit: +280°C (536°F)