Development of Measuring Instruments for Measuring Methane Gas Concentration in a Coal Mine using a Laser Diode and a Light Emitting Diode

Abstract

  A practical method for measuring methane gas concentration in a mine is developed. The method is based on near infrared absorption technique, where a laser diode (LD) and a light emitting diode (LED) are used as light sources. The resolution better than 0.1% is successfully achieved, and the electricity consumption less than 6W, which is about one tenth of that of other current methods using a halogen-lamp.