Coal is mainly composed of carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus. The sum of carbon, hydrogen and oxygen accounts for more than 95% of organic matter, which is a very important energy source. Our country isThe world's first use of coalThe energy release of coal is strong, because it can be efficiently converted into electric energy, so our country80%The above electricity is realized by burning coal. In addition, we also use coal or coal products in our daily life, and industries also use coal. For example, in the metallurgical industry, in the metallurgical process, coal needs to be used to extract the rest of the chemicals. Coal also needs other uses. At present, coal and oil are important energy sources in the world.

How is coal produced? And where does it exist? Under normal temperature and pressure on the surface, the remains of plants accumulated in stagnant water bodies are transformed into peat or sapropelic mud by peat or sapropelic mud; after peat or sapropelic mud is buried ， Due to the decline of the basement of the basin, it sinks to the deep underground, and transforms into lignite by diagenesis; when the temperature and pressure gradually increase, it transforms into bituminous coal to anthracite by metamorphism. It is mainly buried deep underground, so the coal we need must be excavated to get it. A lot of coal may exist hundreds of meters or even kilometers underground. At this time, machines and operators are needed to work underground. However, due to underground fire, gas, coal dust explosion, underground blasting work, slow oxidation of coal, etc., carbon monoxide will be produced, and ventilation will also be stored.In hydrogen sulfide gas, this time will cause serious damage to the personal safety of the operators under the mine, so what kind of harm will carbon monoxide and hydrogen sulfide cause?

After carbon monoxide enters the human body, it first combines with heme in the blood, thus reducing the chance of heme combining with oxygen, making heme lose the function of oxygen transfusion, resulting in "suffocation" of human blood ".0 .08%，40minutes cause headache, dizziness and nausea,0.32%，5~10minutes cause headaches, dizziness,30Minutes cause coma and even death; the same hydrogen sulfide is colorless, slightly sweet, has a strong smell of rotten eggs, highly toxic, and has a strong stimulating effect; it can hinder the biological oxidation process and cause the human body to lack oxygen. When the concentration of hydrogen sulfide in the air is low, it is mainly due to corrosion stimulation, and when the concentration is high, it can cause rapid coma or death. Therefore, when working in mines, attention must be paid to the concentration of carbon monoxide and hydrogen sulfide gas. Once the concentration of gas exceeds the safe range, alarm signals should be given in time. At present, the market generally adopts all-in-one or single gas detection instruments. In fact, the most important thing inside is gas sensors. Most of the gas sensors on the market are one-to-one, so the volume of the overall meter is very large, as a result, it is very inconvenient for operators to use it, and it is troublesome for large workers to carry it under the mine.AlphasenseResearch and development of dual gas sensorCOH-A2, is a dual-gas sensor that can detect both carbon monoxide and hydrogen sulfide. The sensor contains dual-channel outputs, and the two channels do not interfere with each other, so that the outputs will not interfere with each other. The overall sensitivity is high, the linearity is good, and the resolution is high. The volume of the instrument can be greatly reduced, and it can be made into a portable small detector for mining.

Main parameters:

Carbon monoxide channel:

Resolution:0.5ppm

Response timet90(Seconds)<20s<!--20s<--><!--20s<-->

Measurement range:2000 ppm

zero current<0~-4ppm<!--0~-4ppm<--><!--0~-4ppm<-->

Sensitivity: 50-95 nA/ppm, 400ppm co

Linear:Full scale10~40ppmerror,0-400ppmLinear

Overload range:5,000ppm/Stable response to gas pulse concentration

Hydrogen sulfide channel:

Resolution:0.05ppm

Response timet90(Seconds)<30s<!--30s<--><!--30s<-->

Measurement range:200 ppmzero current<0~-0.3ppm<!--0~-0.3ppm<--><!--0~-0.3ppm<-->

Sensitivity:700-1000nA/ppm, 20ppm H2S

Linear:Full scale10~40ppmerror,0-20ppmLinear

Overload range:500ppm/Stable response to gas pulse concentration