Simtronics GD1 MK3, Operating Manual

Page: 61 / 76

GD1 Page 61 of 76 850-816926-EN R06
10. SYSTEM DESCRIPTION
The Simtronics GD1 sets a new standard for toxic gas detection. Using a tunable laser
diode, the GD1 delivers enhanced coverage and fail safe detection. The performance
improvement marks a major step for safety systems and life cycle cost savings.
The GD1 has been designed with features that provide an effective response to the
detection of gas hazards in a wide range of industrial environments from offshore
production facilities to wastewater treatment plants.
At the heart of the detector is a tunable laser diode that eliminates environmental effects
from sun, rain and fog. The laser scans single absorption lines where there is no cross-
interference from other gases. The laser operates in the near infrared wavelength region,
and is invisible to the naked eye. The GD1 laser is eye safe, and does not present any
danger even if looked straight into.
Unlike traditional methods for detecting H
2
S, MOS or EC cell, the GD1 needs no
recalibration and can replace multiple standard detectors to cover the same potential leak
area.
The measurement technique used in the GD1 is intrinsically a baseline-free technique.
Therefore, a calibration of the zero level is never done. The complete optomechanical
design and construction is so stable that an ultra-fast speed of response can be achieved
whilst providing unparalleled service life and detector stability, thus saving on maintenance
and service costs.
10.1. System
The GD1 is an optical open path Gas Detector with a separate transmitter (TX) and receiver
(RX). The transmitter emits infrared laser light which is detected by the receiver. The
detection principle is based on measuring the absorption of light by the free gas molecules
present in the measuring path.
RECEIVER TRANSMITTER
In contrast to traditional hydrocarbon open path detectors which emit broad-banded light,
the GD1 uses a tunable diode laser (TDL) as its light source and emits light at a very narrow
bandwidth. This technology enables high-resolution spectroscopy and the ability to