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Delta F Moisture Sensing Technology
The Delta F 700 Series analyzers use TDLAS technology to measure
moisture in gases. TDLAS is a spectroscopic technique that utilizes
a diode laser as its light source. TDLAS has advantages over other
techniques because the moisture sample only comes in contact with
a few optical components that are made from very robust materials.
It works according to the fundamental principle of Beer's law, therefore,
the reading is stable over time and does not even require calibration.
Tunable Diode Laser Absorption Spectroscopy (TDLAS)
Beer's Law is:
I is the measurement of beam intensity when tuned
to the absorbing wavelength of moisture
Iš is the reference measurement or beam intensity when tuned away
from the moisture absorbing wavelength
S is the fundamental absorption line strength and is a fixed constant
L is the path length of the beam through the sample and is a fixed
constant
N is the number of water molecules contained in the beam path passing
through the sample
Other spectroscopic techniques that follow Beer's Law take the reference
measurement, Iš, by sending the light beam through a different optical
path and generally, utilize a second detector. By rapidly
tuning the laser, Delta F's TDLAS technology uses a single light
source, a single light path and a single detector and, therefore,
does not require any recalibration.
In spectroscopy, a longer path length is one way to achieve more
sensitivity. Inside the Herriott Cell, the laser is reflected
back and forth numerous times by mirrors inside the measuring cell.
By making multiple passes, this increases the laser path length
to achieve extremely high sensitivity. Delta F's TDLAS technology
offers a robust and simple optical design with the sample and reference
measured with a single laser source and a single detector.
Using Lasers for Unmatched Accuracy and Reliability
Drift Free Operation • Combination of self-correcting
optics and the laser line locking onto the water peak removes all
possibility of significant drift.
High Accuracy/ Low Maintenance • Based on Beer's Law, the measurement
requires no field span calibration.
Unparalleled Performance • Spectroscopy allows sub-ppb level
readings instantly! Other measurement techniques with solid
surfaces require lengthy adsorption and desorption times.
Increased Capabilities • When packaged with the NanoTrace II
Oxygen Analyzer, you can easily make both oxygen and moisture measurements
from a single unit.
Click Moisture
Applications and Articles to see how this TDLAS moisture
technology can help your process.
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