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Calibration Chapter 7
Hydro-View / Hydro-Hub User Guide HD0864 Rev 1.0.0 67
15. Continue to re-heat and weigh the material until the weight remains constant between
two heating cycles. This indicates that the material is fully dry.
16. Repeat steps 9-15 for two more samples taken from the collected material.
Note: If using a conventional oven instead of a microwave the same procedure can
be followed except the time required to heat the material must be increased
accordingly. All three samples can be dried at the same time to speed up the process.
17. Calculate the moisture % of the three sub-samples using the following equations:
Dry weight Moisture Content
If the control process in use requires the moisture % to be based on the dry weight (Md)
of the material (Common in the construction industry), the following calculation can be
used:
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀
) =
(
𝐵𝐵 − 𝐶𝐶
)
( 𝐶𝐶 − 𝐴𝐴 )
𝑥𝑥 100
Where A = Weight of the empty bowl
B = Weight of the bowl and wet material
C = Weight of the bowl and the dry material
In the above example the moisture % calculated as:
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀 ) =
(650
− 625)
(625 − 150)
𝑥𝑥 100
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀 ) =
25
475
𝑥𝑥 100
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀
) = 5.26%
Wet Weight Moisture Content
If the control process in use requires the moisture % to be based on the wet weight (Mw)
of the material (Common in the Agricultural and Food industries), the following calculation
can be used:
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀
) =
( 𝐵𝐵 − 𝐶𝐶 )
( 𝐵𝐵 − 𝐴𝐴 )
𝑥𝑥 100
In the above example the moisture % calculated as:
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀 ) =
(650
− 625)
(650
− 150)
𝑥𝑥 100
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀 ) =
25
500
𝑥𝑥 100
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 % ( 𝑀𝑀𝑀𝑀
) = 5%
18. If all three sub-samples are within 0.3% moisture, take an average of the three results.
If the sub-samples are not within 0.3% moisture the test must be repeated. Variations
in the results indicate possible sampling or laboratory errors.
19. Manually add the moisture % result to the calibration chart