预报矿井煤自燃火灾的正压束管监测系统关键技术研究

Study on Key Technology of Positive Pressure Bundle Tube Monitoring System for Predicting Coal Spontaneous Combustion in Mine

为了解决负压束管系统气样传输过程中气体组分和浓度监测值易失真,以及采样滞后时间长的问题,提出以正压输送作为检测气体的输送方式,研制一种正压束管监测系统。对正压泵输出压力进行了理论计算,并在不同负压段束管长度条件下对气样传输滞后时间及流量进行测试,理论计算及测试结果表明:正压泵输出压力宜为0.75 MPa,负压段束管长度须小于320 m。利用不同长度正压段束管进行正压输气试验,结果表明:在负压段束管长度200 m、正压段束管长度5000 m的条件下,气样传输滞后时间仅为872 s,完全满足束管监测系统的精度要求。

In order to solve the problem that in the process of gas transmission in negative pressure bundle tube monitoring system,the composition and monitoring value of the concentration for gas were easily distorted and sampling lag time was long.A positive pressure bundle tube monitoring system was developed based on the condition that the positive pressure transport was used as the transport mode of detecting gas.The output pressure of positive pressure pump was calculated theoretically,and the lag time and flow rate of the gas sample transmission were tested under different lengths of the negative pressure section bundle tubes.The theoretical calculation and test results show that the output pressure of the positive pressure pump should be 0.75 MPa,and the length of the negative pressure bundle tube should be less than 320 m.Positive pressure gas transmission test was carried out by using positive pressure bundle tubes with different lengths.The experimental results show that the lag time of gas sample transmission is only 872 s in the case of a tube length of 200 m in the negative pressure bundle tube and a length of 5000 m in positive bundle tube.It fully meets the accuracy requirements of bundle tube monitoring system.