KROHNE VA 40 ATEX II2G Ex i EN - Manual (Page 8)

2
DEVICE DESCRIPTION
8
VA40
www.krohne.com 06/2013 - 4002262402 - MA VA40-Ex-II2G-AD R02 en
2.7 Ambient temperature / temperature classes
Because of the influence of the temperature of the product, no fixed temperature class is
assigned to variable area flowmeters. In fact, the temperature class of a device is a function of
the temperature of both the product and the environment. There is no distinction between
devices with one or two contacts. The classification is outlined in the following tables.
The tables take into account the following parameters:
• Ambient temperature T
amb.
• Product temperature T
m
Maximum permissible product and ambient temperatures TG21
Maximum permissible product and ambient temperatures MS14/.
The maximum medium and ambient temperature is -20°C...+85°C / -4°F...+185°F.
These values may be limited by the information contained in the installation and operating
instructions. The maximum values listed in the installation and operating instructions must be
taken into consideration.
INFORMATION!
The maximum permissible product temperatures listed in the tables are valid under
the following conditions:
• The measuring device is installed and operated in accordance with the installation
instructions in the manual.
• It must be ensured that the flowmeter is not heated by the effects of additional heat radiation
(sunshine, neighbouring system components) and thus operated above the permissible
ambient temperature range.
• Insulation must be limited to the piping.
Unobstructed ventilation of the indicator part must be ensured.
Supply Type 1 Type 2 Type 3
Temperature class T6 T5 T4...T1 T6 T5 T4...T1 T6 T5 T4...T1
Max. medium
temperature [°C]
70 85 95 60 75 95 35 50 70
Max. medium
temperature [°F]
158 185 203 140 167 203 95 122 158
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