3 conductivity measurement, 4 gas flow regulation, Conductivity measurement – Metrohm 873 Biodiesel Rancimat Manual User Manual
Page 174: Gas flow regulation

7.3 Conductivity measurement
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873 Biodiesel Rancimat
Shutdown temper-
ature
260 ± 11 °C
(if this temperature is exceeded, the heating is shut down, and switched
on again at 210 ± 11 °C)
Heating up time
for the instrument
approx. 45 min (from 20 °C to 120 °C)
approx. 60 min (from 20 °C to 220 °C)
Instrument exter-
nal temperature
< 50 °C
(at operating temperature 220 °C)
7.3
Conductivity measurement
Sensor
Conductivity measuring cell, integrated in the measuring vessel cover
6.0913.130
Structure
Conductivity measuring cell with 2 steel electrodes
Measuring princi-
ple
AC current measurement with 1 kHz frequency and approx. 1.7 V ampli-
tude (peak to peak)
Cell constant
1.00…1.20
(the exact value can be entered manually or determined automatically)
Measuring range
0…400 µS/cm
Resolution
0.1 µS/cm
Maximum error
±1 % ± 0.5 µS/cm
7.4
Gas flow regulation
Pump
Membrane pump
Adjustable range
7…25 L/h
Max. deviation
from the set range
±10 %