Yokogawa In-Situ Gas Analyzer TDLS200 - Manual (Page 26)

4-6 4-7
IM 11Y01B01-01E-A 6th Edition :Feb 13, 2013-00
<4. ANALYZER COMPONENTS>
Laser Diode is either a Vertical Cavity Surface-Emitting Laser (VCSEL) or Distributed Feedback (DFB) that
outputs at wavelengths in the 750nm to 2400nm range (invisible)
depending on the target gas being measured. The primary
output wavelength of the laser is controlled by a thermoelectric
cooling module (Peltier Element). The laser diode is permanently
attached to the module.
Collimating Lens is an optical
component that collimates the diverging light source.
4.4 Check Gas Flow Cell (for On-Line Validation and/or
Line Locking
The Check or Check Gas Flow Cell is a short chamber that exists
between the laser collimating lens and the standard Process
isolation window. The cell is sealed with double O-rings and is
in series with the measurement optical path. The body has two
Swagelok style tube fittings welded on that serve as inlet and
outlet ports for the nitrogen purge gas or calibration check gas as
appropriate.
The Check gas flow cell is used for performing on-line validations (or Dynamic Spiking) while the analyzer is mounted
on the Process. This feature allows for the analyzer to be validated without removing it from the Process location.
By introducing a gas of known target gas concentration, at a given temperature and pressure, the analyzer can
determine if the Validation routine has been PASSED or FAILED.
This cell can also be used for Line Locking applications, such as %CO for combustion applications. Refer to
Non-Process Parameters for details of how to configure the software when implementing a line-locking application.
Please also refer to project specific drawings for detail of how to configure the tubing/valving when implementing line
locking.
The various parameters that enable the validation are all configurable within the TDLS200 software. Refer to the
Validation and Calibration section of this User Guide for further details.
Laser
Module Check Gas
Flow Cell
Body
Window
Figure 11 - Check Gas Flow Cell