Methane gas is a kind of flammable and explosive gas

an important industry material and daily life gas

and a main gas that engenders greenhouse domino offect

therefore

the quick and real time detection of methane and volume fraction is very important.With the combination of optical fiber sensing technology and difference detecting technology and computer data processing technology

the novel volume fraction online detecting system which employs time-sharing processing difference technology is designed

it can detect volume fraction real-time and continuously.Time-sharing processing difference photo-absorption technology is employed.Alternative chopping is automatically realized by illuminant driver

difference measurement on methane

with the low-cost light emitting diode as the light source is completed.Taking the powerful software Visual C++ 6.0 as tool

the real time online dynamic monitor software is designed based on user interface.The measurement range is 0

2

5 %

the resolution is 50×10（-6）

the minimum sensitivity is 142.35×10（-6）.