JUMO 902820 PROCESStemp RTD Temperature Probe for Process Technology (Also with ATEX Approval) Ex i Operating Manual - Manual (Page 8)

The ignition or smoldering temperature of the dust or dust-air mixture that is present must
be defined or determined by the operator of the plant or system!
400
300
200
100
0
0 10 20 30 40 50
Thickness of layer, in mm
Smoldering temperature
with a 5 mm thick layer
Ma
x
im
u
m
p
e
rm
iss
ib
le
surfa
c
e
t
e
mp
erat
ur
e
of
eq
u
ipm
e
nt
, in
°C
400 °C
T
5 mm
320 °C
T
5 mm
< 400 °C
250 °C
T
5 mm
< 320 °C
400 °C
320 °C
250 °C
Figure 2: Reduction of the maximum permissible surface temperature
with increasing thickness of the dust layer
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