ASTM D 4944 AASHTO T 217
This moisture meter has been designed for rapid and accurate
determination of the moisture content of a wide variety of materials.
It is torsion wire instruments, the torque being applied to one end of
the wire be means of a calibrated drum to balance the loss of weight
as the test sample dries under infrared radiation. The speed of drying
(about 30 min) thus obtained, combined with the frictionless
balancing system gives the result as accurate as those obtained by
standard oven drying method. Since drying weighing are
simultaneous, it is useful specially for determination of moisture in
substances that quickly reabsorbs moisture after drying. The infrared
radiation is controlled by a voltage regulator and thereby provided
excellent heat control. The instrument is provided with an indicator
lamp, which glows when the unit is switched on. The torsion balance
has a built-in magnetic damper or reduce pan vibrations that enables
quick weighing. The balance scale (drum) is divided in terms of
moisture percentage on wet weight basis, which are read directly
from it. Graduations are from 0 to 100% in 0.2 % divisions, but
readings may be estimated to 0.1% moisture content. Suitable for
operation on 220 V, 50Hz, Single phase, AC Supply.