11 - 3
Cyclops L
Portable Thermometers
User Guide
11.3 Emissivity values for Cyclops 055L thermometers
In order to get a true representation of the metal temperature, it is necessary
to set the emissivity value. For liquid steels, this is typically in the range 0.50
to 0.55, but is known to vary slightly with alloy type and will certainly differ for
other metals.
The emissivity value may be set relative to a dip thermocouple or other
reference measurement by viewing the freshly cleaned surface whilst in the
melting furnace. The procedure for obtaining the emissivity value is very quick
and simple to perform, as described below:
1) From as near to the vertical as feasible, sight the
Cyclops 055L
onto the
clean surface of the molten metal and press the trigger to read.
2) When the instrument is showing a stable temperature value, obtain a dip
thermocouple, or other reference reading.
3) When the trigger is released, the readings are frozen on the side display.
Press the ‘select’ key
to go into ‘menu’ mode, then press the
arrow
key to highlight the ‘
e
’ icon. Press the
key to select this option.
4) The screen will display the current emissivity value, together with the
most recently recorded temperature. Changing the emissivity value will
show the calculated temperature that would have been displayed at the
new emissivity value.
5) Adjust the emissivity value up or down until the calculated temperature
corresponds as closely as possible with the reference reading.
6) Press the
key to enter the new emissivity value, then press the
key
to go to the exit icon and press
to return to ‘measure’ mode.
All subsequent readings will now use the newly set emissivity value.
11.4 Emissivity values for Cyclops 390L thermometers
In order to obtain accurate temperature measurements, the emissivity value of
the target surface must be known.
For a
Cyclops 390L
sighting onto carbon steel slabs, the target emissivity is
typically between 0.8 to 0.9, depending on the exact composition of the steel
and level of oxidation.
Contact AMETEK Land for further information.
11.4.1 Emissivity values of Reformer Tubes
When measuring the temperature of reformer tubes, we strongly recommend
that you use a Land Gold Cup Probe to obtain an initial accurate temperature
measurement, from which you can determine the emissivity of your tubes.
A typical emissivity value is 0.85. AMETEK Land also provide a service in which
we can analyse a sample of your material to determine the precise emissivity.
