Gehaka G650i, User Manual

Page: 40 / 48

40
I
Moisture Meter G650
i
Ice or Snow
Samples containing ice or snow will not be satisfactorily measured. Frozen samples may
be analyzed provided they are left to heat up in a hermetically closed container to get
them closer to room temperature. Use the average value of 3 or more readings. Below the
temperature range of 5 ºC, perform 3 readings and use the average value.
Surface Moisture
Grains obtained from a warmed warehouse when getting in touch with humid air develop
a surface moisture. The same occurs with some cereals uncovered during a rainfall, which
will keep surface moisture for some days unless an artificial heat is applied for drying them.
Surface moisture presents very low impedance to the high-frequency current flow, thus
incorrect readings will be obtained.
Moisture Measurement Processes
There are two methods for measuring moisture in cereals: the primary one and the
secondary one. The primary method consists on a procedure using the vented oven. This
procedure is time-consuming and would not obviously be convenient for use on grain
reception. For this reason, the secondary method was developed, so that using the cereal
electrical properties, quick measurements can be made.
Although research works and technological developments have been carried out in the
field of electronics and also on the properties of cereals, it is not possible to analyze the
cereal without some variation. Some of the involved facts are discussed below.
We recommend that the product to be measured in the G650
i
shall be clean and free from
any impurities that could interfere in the moisture measurement. We should consider that,
during the instrument calibration process with the oven, it was always used the product
clean.
Unfortunately, a cereal cannot be measured until the harvest is completed and the
calibration cannot be modified until the measurement of a sufficient number of samples,
in order to be able to determine the change in the cereal electrical properties.
Extreme conditions