GE PM880, Руководство по эксплуатации и установке

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Application of the Hygrometer (900-901D1) A-33
4/9/98
B: SPECIAL CASE (cont.)
c. Measure the dew point of the known test sample with the
GE Panametrics hygrometer. For purposes of this example,
assume the measured dew point to be -10°C.
d. Using a straightedge on the nomograph in Figure A-2,
connect the known 10 PPM
W
moisture content with the
measured dew point of -10°C, and read a K value of 5.1 on
the center scale.
e. Using the straightedge, connect the above K value of 5.1
with the measured 10°C dew point of the original liquid,
and read the actual moisture content of
47 PPM
W
on the
left scale.
Note:
The saturation value at 50°C for this liquid could also
have been determined by connecting the K value of 5.1
with the ambient temperature of 50°C and reading a value
of 475 PPM
W
on the right scale.
For many applications, a knowledge of the absolute moisture
content of the liquid is not required. Either the dew point of the
liquid or its percent saturation is the only value needed. For such
applications, the saturation value for the liquid need not be
known. The GE Panametrics hygrometer can be used directly to
determine the dew point, and then the percent saturation can be
calculated from the vapor pressures of water at the measured dew
point and at the ambient temperature of the liquid:
% Saturation
C
C
S
------
100
×
P
W
P
S
--------
100
×
= =