LaserGasTM II Open Path Monitor
The Open Path monitor from NEO Monitors AS is designed for
long distance monitoring in ambient air, monitoring of production halls, gas
fencing or leak detection of gases such as HF, CH4, H2S
(see ‘Table of Gases’ below). Measurement lengths of up
to 500 m are possible. Based on the well-proven tuneable diode laser (TDLAS)
technology the instrument has a number of unique features.
Features
- Up to 500 m measurement path
- Response time down
to one second
- No cross
interference from other gases
- Very low detection
limits (ppb and low ppm)
- Unaffected by fog
or rain down to <1% transmission
- Low cost of ownership
- Ethernet connection (optional)
- Portable, battery powered version
available
The monitor consists of
a transceiver and retro-reflector unit, which are both suitable for outdoor
use. As option a portable, battery-powered version of the LaserGas II OP is
available containing a control keypad and a flash memory for data logging. Different
path lengths between 1 and 500 m are easily measured by entering the selected
distance (automatic phase correction included in HW).
Measuring
principle
LaserGas II monitors
employ the measurement principle known as ''''''''single line spectroscopy'''''''', which
eliminates cross interference from other gases. A single gas absorption line
with no interference is chosen in the near IR spectral range and scanned by a
single-mode diode laser. A retro-reflector located opposite to the laser
reflects the light back to the transceiver. A detector collects the returned
light for further analysis and calculation of the gas concentration.
Installation
and Operation
The LaserGas II OP
monitor is easy to install using a special x/y alignment platform or tripod for
the transceiver and rigid platform or tripod for the retro-reflector. A visible
aiming laser and sighting optics simplify alignment even over long distances. For
installation in hazardous areas an ATEX approved EEx P solution is available. The
instrument contains no moving parts, thereby limiting preventive maintenance to
visual inspection and cleaning of optical windows. A fan is advisable in rough
industrial environments to prevent dust from fouling the optical windows. Calibration checks are recommended every 6 - 12 months.
Table of Gases
|
Gas
|
Detection limit
|
Min meas. range
|
|
|
|
NH3
|
0.008 ppm
|
0.006 mg/m3
|
0 - 0.6 mg/m3
|
|
|
|
HCl
|
0.003 ppm
|
0.004 mg/m3
|
0 - 0.4 mg/m3
|
|
|
|
HF
|
0.001 ppm
|
0.001 mg/m3
|
0 - 0.1 mg/m3
|
|
|
|
H2S
|
0.15 ppm
|
0.23 mg/m3
|
0 - 20 mg/m3
|
|
|
|
H2O
|
0.002 ppm
|
0.001 mg/m3
|
0 - 0.1 mg/m3
|
|
|
|
CO
|
1.5 ppm
|
1.9 mg/m3
|
0 - 200 mg/m3
|
|
|
|
CO (low conc)
|
0.015 ppm
|
0.019 mg/m3
|
0 - 2 mg/m3
|
|
|
|
NO
|
0.75 ppm
|
1 mg/m3
|
0 - 100 mg/m3
|
|
|
|
N2O
|
0.25 ppm
|
0.5 mg/m3
|
0 - 50 mg/m3
|
|
|
|
CH4
|
0.01 ppm
|
0.007 mg/m3
|
0 - 0.7 mg/m3
|
|
|
|
NH3 + H2O
|
0.01 ppm
|
0.008 mg/m3 / 0.003 %
|
0-1 mg/m3 / 0-0.3%
|
|
|
|
HF + H2O
|
0.001 ppm
|
0.001 mg/m3 / 0.001 %
|
0-0.1 mg/m3 / 0-0.1 %
|
|
|
NOTE: Detection limits are specified as two standard
deviations for 100 m optical path length and gas temperature / pressure = 25 °C / 1 bar abs. Other gases are available on request.
Main
applications
The LaserGas II OP
monitors play an important role in continuous monitoring across a wide range of
industrial applications. The following are some of the most typical
applications:
·
Monitoring of production
halls (e.g. Aluminium smelters)
·
Leak detection
·
Gas fencing in the
proximity of industries
·
Fire protection
·
Monitoring of traffic
exhaust