LaserGasTM II Single Path Monitor
Single Path monitors are designed
for in-situ measurement with path lengths in the range 0.5 - 15 m (pipes,
stacks, ducts). This model operates over the range 2 - 3 bar maximum pressure
and temperatures up to 500C, but it is possible to operate at up to 20 bar and
1500C with some gases (see Table of
Gases below). Based on the well-proven tuneable diode laser (TDLAS)
technology the instrument has a number of unique features.
Features
- Response time down to one second
- No cross interference from other gases
- No gas sampling - in-situ measurement
- Very low detection limits (ppb and low
ppm)
- Wide range of process conditions
possible
- Suitable for high dust environments
- Low cost of ownership
- Ethernet connection (optional)
- ATEX approved EEx P solution available
The monitors' very compact design
comprises a transmitter and receiver unit, only. Both are protection classified
to IP66 for outdoor use. Measurement readings are provided through standard
4-20mA current loops, a fibre-optic output or the optional Ethernet interface.
The latter enables communication via a local area network or the Internet.
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 detector located opposite the laser detects the
light absorption caused by the target gas molecules, after which the gas
concentration is calculated. Automatic correction for temperature, pressure,
and dust load variations is included (see Technology for
more information).
Installation
and Operation
The LaserGas II SP monitor is easy
to install and designed to operate in very rough industrial environments. The
transmitter and receiver units are mounted directly onto the duct or stack
flanges. For installation in hazardous areas an ATEX approved EEx P solution is
available. By-pass and extractive configurations are also possible. The
instrument contains no moving parts, thereby limiting preventive maintenance to
visual inspection and cleaning of optical windows. Purging with instrument air
or nitrogen prevents dust from fouling the optical windows. Calibration checks
are recommended every 6 - 12 months, only.
Table of Gases
|
Gas
|
Detection limit
|
Max temp.
|
Max pressure
|
|
|
|
NH3
|
0.15 ppm
|
0.11 mg/m3
|
500 C
|
2 bar abs.
|
|
|
|
HCl
|
0.05 ppm
|
0.08 mg/m3
|
400 C
|
2 bar abs.
|
|
|
|
HF
|
0.015 ppm
|
0.013 mg/m3
|
400 C
|
2 bar abs.
|
|
|
|
H2S
|
3 ppm
|
4.5 mg/m3
|
300 C
|
2 bar abs.
|
|
|
|
O2
|
0.01 %
|
1500 C
|
20 bar abs.
|
|
|
|
H2O
|
0.03 ppm
|
0.024 mg/m3
|
1500 C
|
2 bar abs.
|
|
|
|
CO
|
30 ppm
|
38 mg/m3
|
1500 C
|
2 bar abs.
|
|
|
|
CO2
|
30 ppm
|
59 mg/m3
|
1500 C
|
2 bar abs.
|
|
|
|
CO (low C)
|
0.3 ppm
|
0.4 mg/m3
|
300 C
|
2 bar abs.
|
|
|
|
CO2 (low C)
|
0.2 ppm
|
0.4 mg/m3
|
300 C
|
2 bar abs.
|
|
|
|
NO
|
15 ppm
|
20 mg/m3
|
300 C
|
2 bar abs.
|
|
|
|
N2O
|
5 ppm
|
10 mg/m3
|
200 C
|
2 bar abs.
|
|
|
|
HCN
|
0.3 ppm
|
0.36 mg/m3
|
300 C
|
2 bar abs.
|
|
|
|
CH4
|
0.2 ppm
|
0.14 mg/m3
|
300 C
|
3 bar abs.
|
|
|
|
C2H2
|
0.1 ppm
|
0.12 mg/m3
|
200 C
|
2 bar abs.
|
|
|
|
C3H6
|
0.01 %
|
200 C
|
3 bar abs.
|
|
|
|
CH3I
|
3 ppm
|
9 mg/m3
|
200 C
|
2 bar abs.
|
|
|
|
CH3OH
|
0.05 %
|
200 C
|
2 bar abs.
|
|
|
|
NH3 + H2O
|
0.2 ppm
|
0,15 mg/m3 / 0.05 % *
|
500 C
|
1.5 bar abs.
|
|
|
|
HCl + H2O
|
0.1 ppm
|
0.16 mg/m3 / 0.05 % *
|
400 C
|
1.5 bar abs.
|
|
|
|
HF + H2O
|
0.02 ppm
|
0.018 mg/m3 / 0.01 % *
|
400 C
|
1.5 bar abs.
|
|
|
|
CO + CO2
|
0.01 % (both)
|
300 C
|
1.5 bar abs.
|
|
|
NOTE: Detection limits are specified as two standard deviations
for 1 m optical path length and gas temperature / pressure = 25 C / 1 bar abs.
(* H2O specified for 180 C). The recommended minimum measurement range is the
detection limit multiplied by 100. Other gases such as NO2, C2H4, C2H6, HBr,
and HI are available on request.
Data sheet for
download
LaserGas
II Single Path (Acrobat 289661 bytes)(.pdf)