KROHNE H250 M10 ATEX II3D Ex t EN - Manual (Page 7)

DEVICE DESCRIPTION
2
7
H250 M10
www.krohne.com 03/2011 - 4001348101- MA H250/M10-Ex-II3G-AD R01 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. The classification is outlined in the
following tables.
The tables take into account the following parameters:
• Ambient temperature T
amb.
• Product temperature T
m
• Nominal DN
• Heat resistance of the connecting cable
For certain device version, lower values apply due to differing boundary conditions (e.g. lining
materials).
Here the user should consult the technical data sheet.
Maximum permitted product temperature °C
Maximum permitted product temperature °F
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 installation and operating 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.
Maximum permitted product temperature T
m
(°C) as a function of the maximum continuous
operating temperature of the cable T
max
Ambient temp. Cable T
max
= 70°C T
max
= 80°C Cable T
max
= 90°C
-40...+40 180 200 200
-40...+50 135 190 200
-40...+60 85 145 200
Maximum permitted product temperature T
m
(°F) as a function of the maximum continuous
operating temperature of the cable T
max
Ambient temp. Cable T
max
= 158°F Cable T
max
= 176°F Cable T
max
= 194°F
-40...+104 356 392 392
-40...+122 275 374 392
-40...+140 185 293 392
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