KROHNE DK 32-DK 34 ATEX II3G Ex nA-ic EN - Manual (Page 5)

DEVICE DESCRIPTION
2
5
DK32 DK34
www.krohne.com 03/2013 - 4002148602 AD DK32/34 II3G R03 en
2.4 Flammable products
Atmospheric conditions Atmospheric conditions Atmospheric conditions 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°C...+60°C /
-4°F...140°F and P
atm
= 0.8...1.1bar. Outside of this range, no key data are available as to ignition
behaviour for most mixtures.
Operating conditions Operating conditions Operating conditions 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 3G according to EN 60079-0, EN 60079-11 and EN
60079-15 for use in zone 2.
For more information see the chapter entitled "Flammable products".
CAUTION!
Operation with flammable products is only permissible if no explosive fuel/air mixture is formed
on the interior of the flowmeter under operating conditions. The user is responsible for the safe
operation of the flowmeter with regard to the temperatures and pressures 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.
INFORMATION!
Definition of Zone 2 according to EN 1127-1, Appendix B:
An area in which an explosive atmosphere as a result of the mixture of flammable substances in
the form of gas, steam or mist with air is not expected to occur under normal operation. If,
however, such an atmosphere does occur it only lasts for a brief period of time.
AD_DK32_34_II3G_R03_en_4002148602_PRT.book Page 5 Thursday, March 7, 2013 6:42 AM