DEVICE DESCRIPTION 2
11
VA FLOWMETERS
www.krohne.com09/2022 - 4000419908 - AD VA Mech Ex Gb-Db R08 en
2.4 Flammable products
Atmospheric conditions:
The standard atmospheric conditions under which it may be assumed that Ex equipment can be
operated are:
• Temperature: -20...+60°C / -4...+140°F
• Pressure: 80...110 kPa (0.8...1.1 bar) / 11.6...15.9 psi
• Air with normal oxygen content, typically 21%v/v
Ex equipment operating outside the standard temperature range must be tested and certified
(
e.g.
for ambient temperature range -40...+65°C / -40...+149°F).
Ex equipment operating outside the standard atmospheric pressure range and standard oxygen
conte
nt is not permitted.
Operating conditions:
The measuring unit of variable area flowmeters operate outside the standard atmospheric
pressure range, which means that explosion protection, regardless of the zone assignment, is
fundamentally not applicable for the measuring unit (piping).
WARNING!
Operation with flammable products is only permitted as long as no explosive fuel/air mixture
builds up inside of the piping at the same time the atmospheric conditions are exceeded.
The operator is responsible to ensure that the flowmeter is operated safely in terms of the
tempe
rature and pressure of the products used. In case of operation with flammable products
the measuring units must be included in the periodic pressure tests of the piping.
The max. allowable operating pressure PS printed on the nameplate is to be considered.
The following versions require dust-free gases or liquids. Gases containing solid particles or
liqui
d droplets are not permitted. The products must reach the stated minimum conductivity.
The limit of the stated maximum nominal flow rate must be observed.
Device type Minimum conductivity in µS/m Maximum flow rate Q
max
H250/C... 0.01 -
VA40 0.001 5-times
GA24 - 10-times
DK46 / DK47
DK48 / DK800
- 20-times
DK46PV / DK47PV
DK48PV / DK800PV
0.001 20-times
Table 2-1: Minimum conductivity of product and maximum flow for the device type
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