Ametek 3050-AP, Руководство пользователя

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Overview 1-1
CHAPTER 1
Overview
The 3050-AP Moisture Analyzer is a smart sensor that measures trace concen-
trations of moisture in a process gas stream. The 3050-AP is compatible with
He, Ar, Ne, Xe, Kr, O
2
, N
2
, NO, CO, CO
2
, refrigerants, air, and specialty gases.
The analyzer is calibrated to measure moisture contents from 1 to 2500 ppmv.
Data output can be in units of ppmv, ppmw, dew point Centigrade, dew
point Fahrenheit, lb/mmscf, and mg/Nm
3
.
The heart of the 3050-AP is a quartz crystal microbalance (QCM) sensor that
is sensitive to moisture. The QCM moisture sensor is simply a quartz crys-
tal oscillator, in which the quartz crystal has been coated with a proprietary
hygroscopic coating. This coating selectively, and reversibly, absorbs moisture
from a sample gas stream. As the crystal is exposed to a gas stream containing
water vapor, the hygroscopic coating absorbs moisture from the gas stream,
changing the mass of the coating. Changes in the mass are detected as chang-
es in the natural resonance frequency of the oscillator.
The QCM sensor is alternately exposed to the sample gas and a dry reference
gas. A dry reference gas is produced by passing a portion of the sample gas
through a dryer to remove any moisture present (i.e. - the moisture content
of the dry reference is less than 0.025 ppmv). The difference in the resonant
frequency of the QCM sensor, as measured when exposed to each of the two
Figure 1.1: 3050-AP Analyzer