TECHNOLOGY FOCUS
TDLAS – A SUPERIOR MOISTURE SENSING SOLUTION
Servomex ’ s moisture analysis technology uses Tunable Diode Laser Absorption Spectroscopy ( TDLAS ) to measure trace moisture in pure gases . Using a simple , robust design , it has a single laser source and single detector to measure the sample and reference gases .
The TDL sensing technique provides significant benefits compared with other measurement techniques , as the moisture sample comes only into contact with a few optical components made from very robust materials .
Working according to the fundamental principle of Beer ’ s law , it delivers a reading which is stable over time and never requires calibration .
To provide a more sensitive measurement , our sensors use a Herriott cell to reflect the laser back and forth numerous times , using mirrors inside the measuring cell . This increases the laser path length , achieving extremely high sensitivity .
TDLAS moisture sensing delivers exceptional performance capable of measuring down to industryleading sub-ppb levels , driftfree operation , high accuracy , and low maintenance . This is achieved through self-correcting optics and laser line locking onto the water peak , removing all possibility of significant drift .
TDLAS sensor
Wavelength
LASER
Modulated
Cell
Window Multi-pass Herriott Cell
H 2 O Standard
Focusing
Mirror Gas Outlet
Reference Detector
Sample Detector
Reference Beam
Gas Inlet
Mirrors
Gas analysis using the DF-700 ' s TDLAS technology
P14