KROHNE H250 M10 ATEX II3D Ex t EN - Manual (Page 6)

2
DEVICE DESCRIPTION
6
H250 M10
www.krohne.com 03/2011 - 4001348101- MA H250/M10-Ex-II3G-AD R01 en
2.4 Flammable products
Atmospheric conditions
An explosive atmosphere is a mixture of air and flammable gases, vapours, mists or dusts under
atmospheric conditions. The following values define it:
T
atm
= -20...+60°C / -4...+140°F and P
atm
= 0.8...1.1 bar.
Outside of this range, no key data are available as to ignition behaviour for most mixtures.
Operating conditions
Variable area flowmeters operate outside of atmospheric conditions, which means that
explosion protection according to Directive 94/9/EC (ATEX) – regardless of the zone assignment
–
is fundamentally not applicable due to the lack of key safety data for the interior of the
measuring section.
2.5 Equipment category
The flowmeters are designed in category II 3D according to EN61241-0:2006 and EN 61241-
1:2004 for use in zone 22.
2.6 Protection types
The variable area flowmeter is designed with protection type "Protection by enclosure"
according to EN 61241-1:2004. Dust protection is guaranteed by the use of a housing which
provides appropriate protection against penetration by dust.
The marking is: II 3 D Ex tD A22 IP66 T65 II 3 D Ex tD A22 IP66 T65 II 3 D Ex tD A22 IP66 T65 II 3 D Ex tD A22 IP66 T65°C C C C
The marking contains the following information:
CAUTION!
Operation with flammable products is only permitted as long as no explosive fuel/air mixture
builds up on the inside of the flowmeter under operating conditions. The operator is responsible
for ensuring that the flowmeter is operated safely as regards the temperature 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 system. When using the device version H250/C...
(PTFE-liner, nonconductive) the min. conductivity of the medium must be 10
-8 S/m, in order to
avoid the electrostatic charge.
The marking contains the following information: The marking contains the following information: The marking contains the following information: The marking contains the following information:
II IIII II Group II explosion protection
3333 Equipment category 3
D D D D Dust explosion protection
tD tD tD tD Protection by enclosures
A22 A22 A22 A22 Surface temperature according to method A, use in zone 22
IP66 IP66 IP66 IP66 Foreign bodies and water pollution control
T65 T65 T65 T65°C C C C Maximum surface temperature of the converter housing without dust coating at ambient
temperature 60°C / 140°F and product temperature 60°C / 140°F
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