4/9/98
A-42 Application of the Hygrometer (900-901D1)
B. Laboratory Procedures (cont.)
2. An alternative technique involves driving the moisture from
the solids sample by heating:
a. The evaporated moisture is directed into a chamber of
known volume, which contains a calibrated moisture
sensor.
b. Convert the measured dew point of the chamber into a
water vapor pressure, as discussed earlier in this appendix.
From the known volume of the chamber and the measured
vapor pressure (dew point) of the water, the number of
moles of water in the chamber can be calculated and
related to the percent by weight of water in the test sample.
Although this technique is somewhat tedious, it can be used
successfully. An empirical calibration of the procedure may
be performed by using hydrated solids of known moisture
content for test samples.
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