KERN & SOHN MLS 50-3C - Manual (Page 63)

MLS_C-BA-e-1330 63
8. Determine and enter corrective factor
Certain materials emit more heat than is introduced from the outside. Dark
substances for instance absorb heat and falsify measured results.
In order to achieve an accurate measured result it is necessary to make a correction.
Setting a corrective factor allows the user to correct differences between the set
temperature of the moisture meter and the actually measured temperature on the
specimen with the help of a temperature calibration set.
Determination of corrective factor:
● Carry out drying on sample
● Record measured result
● Carry out drying on second sample. For this purpose choose a sample amount
that is large enough to dip the measuring probe of the temperature calibration set
into the sample.
● Record measured result of moisture meter und temperature calibration set.
● Determination of corrective factor according to the formula below:
T (measured) – T (set)
Correction = ----------------------------------------------
T (set)
Example: The measured temperature is 121°C, the set temperature is 110°C; from
this follows a correction of 0.11.
Typical materials with high temperature emission:
Material Set temperature Measured
temperature
Correction factor
Flour
100°C 103.7°C 0.04
Coal dust
100°C 122°C 0.22
Damp tea leaves
100°C 120.5°C 0.20
Dry tea leaves
100°C 108.5°C 0.08
Cement
100°C 121°C 0.21