2.3.2.2.2 On an artificial HOT-SPOT
The second way of surface temperature limiting is to create an artificial hot-spot.
In order to guarantee the limiter sensor measures the highest possible temperature of the installation, the temperature sensor of the
limiter shall be installed on an artificial hotspot.
Figure 7: Artificial hot-spot
Important guidelines on sensor positioning and installation:
•
The correct position is on top of the pipe. See Figure 7.
•
Fix the insulation pad with sufficient glass tape. (GT-66 or GS-54)
•
Guide the heater from the bottom of the pipe to the insulation pad and fix it well so that it keeps its position.
•
The sensor needs to be attached with sufficient glass tape to the heater. Use two bands of glass tape to ensure its position.
•
The lead wire needs to leave the insulation so that no moisture can enter the cladding-insulation system. Fix the lead wire to the pipe
with glass tape if needed to ensure the stability of the hot spot system.
•
Make sure that the nominal insulation thickness is respected over the hot spot, it might be necessary to use oversized insulation shells.
Limiter temperature setting:
•
The limiter value (T
) needs to be set at the maximum allowed surface temperature (T
lim
•
T
= T
– 10. Temperatures in Kelvin or Celsius.
lim
max
) minus 10 K.
max
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