Research And Development Of Infrared Carbon Monoxide Detector In Mine Environment

With the increasing demand for coal mine,it is very important to protect the safety of mineral production.In recent years,due to the explosion of coal mine disasters increased year by year,has brought great loss of the state and people’s life and property safety.In addition to methane which is the main gas caused explosion,Carbon Monoxide which is an inflammable and explosive gas is also the culprit caused of explosion and fire.Developing an independent intellectual property rights,low cost,reliable,fast response of infrared carbon monoxide detector in mine environment has been imminent.The topic of this paper comes Chinese National Science and technology Support Plan "major accident of water,fire prevention technology and equipment research in mine" the project name is:infrared carbon monoxide detector(sensor)research and development in mine environment(project number:2013BAK06B04).By employing a self-fabricated spherical mirror as light-collector and multi-pass chamber,a differential carbon monoxide(CO)concentration sensing device was experimentally demonstrated.The device adopts single-source dual-channel detection method to eliminate the interferences from light source,optical path and environmental change.The detection principle was described,and both the optical part and the electrical part were designed and developed.We successfully developed the ICD-I type infrared detector of carbon monoxide.Experiments were carried out to figure out the sensing performances on CO concentration.The results indicate that,the minimum detection limit(MDL)is about 10 ppm.As the concentration gets larger than 100 ppm,the relative detection error falls into the range of-1.7%～+1.9%.The maximum relative errors of 12 hours long-term measurement on the 100 and 1000 ppm CO gas samples are about 0.9%and 5.5%,respectively.The proposed detector shows potential applications in CO detection under the circumstances of coal-mine production.In addition,we design the virtual lock-in amplifier for a virtual carbon monoxide detection system,effectively to improve the detection performance of the virtual detection system.In view of the virtual system for testing,we carried out experiments of gas and the detection performance of the system is analyzed.The relative detection error within the range of 0～0.4%is less than 4.1%.Long-term monitoring within 24 hours on the detection results of 0.1%and 0.4%indicates that the relative errors are less than 9.8%and 2.2%,respectively.Actual results of this virtual system in paper are very promising and show that the technique allows for detection of CO concentrations.At the same time based on the ICD-type Ⅰ infrared carbon monoxide detector,by using the method of time division multiplexing,we studies a multi gases detection model,application of MEMS broadband light source on multi gases detection lays the basis for further study.The innovative points of this paper are:ⅰ.According to the characteristics of the light source,we designed and fabricated with matching optical path and the collecting chamber:(ⅰ)the diverging light source IR55 angle is 15 degrees,making the path with matching for spherical mirror condenser chamber for 40cm;(ⅱ)light of light source ReflectIR-PIS emitted is parallel making the path with matching for plane mirror condensing gas chamber for 80cmⅱ.The lock-in amplifier technique is applied to the infrared gas detection,independently developing a lock-in amplifier hybrid of 4 Hz,and based on a lock-in amplifier hybrid of 4 Hz,we successfully developed the ICD-I type infrared detector of carbon monoxide,the minimum detection limit of the prototype is about 10 ppm.and it greatly improves the system signal-to-noise ratio,and improves the stability and sensitivity of the instrument.ⅲ.Relying on the ICD-type Ⅰ infrared carbon monoxide detector,from two aspects of electrical system and optical system extensibility research:(ⅰ)Based on excellent data processing ability of virtual software platform Lab VIEW,we design a virtual lock in amplifier,and build a virtual infrared carbon monoxide detector which is applicated in the field of gas detection.(ⅱ)According to the structural characteristics of carbon monoxide detector independently developed and further improvement,by using the method of time-sharing multiplexing,we can realize the detection of various gases.