Gas sensing based on optical fibre coupled diode laser spectroscopy: a new approach to sensor systems for safety monitoring

Brian Culshaw, W. Johnstone, G. Stewart, K. Duffin, Iain S. Mauchline, Douglas Walsh

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Abstract

We describe an entirely passive fibre optic network which senses, amongst other species, CH¬4¬ and CO¬¬2 , with sensitivity and selectivity compatible with safety sensing in the mine environment. The basic principle is that a single laser diode source targeted to a particular species addresses up to 200 sensing points which may be spread over an area of dimensions ten or more km. The detection and processing electronics is typically located with the laser source. Several laser sources can be introduced in parallel to enable monitoring multiple species. The network itself, entirely linked through optical fibre, is inherently intrinsically safe. It is self checking for faults at the sensing location and continuously self calibrating. In the methane sensing mode its sensitivity is sub 100ppm and it responds accurately up to 100% methane. It is therefore capable of detecting extremely hazardous gas pockets which are completely missed by other sensor technologies. The network has demonstrated stability with zero maintenance or recalibration over periods in excess of two years. We believe that this system offers unique benefits in the context of mine safety and ventilation system monitoring.
Original languageEnglish
Pages949-958
Number of pages9
Publication statusPublished - Nov 2009
Event9th IMVC Mine Ventilation Conference - Delhi, India
Duration: 10 Nov 2009 → …

Conference

Conference9th IMVC Mine Ventilation Conference
CountryIndia
CityDelhi
Period10/11/09 → …

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Keywords

  • methane detection
  • optical systems
  • tunnels

Cite this

Culshaw, B., Johnstone, W., Stewart, G., Duffin, K., Mauchline, I. S., & Walsh, D. (2009). Gas sensing based on optical fibre coupled diode laser spectroscopy: a new approach to sensor systems for safety monitoring. 949-958. Paper presented at 9th IMVC Mine Ventilation Conference, Delhi, India.