基于无线传感器网络的市政下水道可燃气体监测系统设计及应用

为防止下水道可燃气体积聚引发爆炸事故,利用无线传感器网络技术设计了市政下水道可燃气体监测系统.实测结果表明:气体传感器监测数据相对误差在2.0%以内,无线数据收发设备的年发送成功率达到98.0%,满足工程运用需求,系统具有较高的可靠性和稳定性.结合无线网络覆盖范围广、实时在线的特点,该系统实现了对不同区域下水道内可燃气体浓度的远程监测,为下水道的安全预警提供了有效依据.

Design and application of the municipal sewer combustible gas monitoring system based on remote radio-sensing network

The paper is to introduce its author's work on designing and application of the municipal sewer combustible gas monitoring system by means of the remote radio-sensing network technology. As is known, the concentrations of all combustible gases and the different nodes can be made to be monitored through remote on-line sensing monitoring by using a visual chart and a warning-prompt device. The results gained through careful measurement and inspection indicate that all-the-year around successful sending rate can reach 98.0% , with the relative deflection error reduced to less than 2% , with highreliability and stability. Based on the above technical reality, this paper is engaged in designing a remote on-line monitoring system for safety control and early warning of urban municipal sewer as a sort of supervision platform. The monitoring system is composed of a gas sensor module, a signal processing module, a data transmission module and a supervision center. For convenience, the infrared sensor has been set up at the head of the inspection well where the combustible gas (mainly methane) is most likely to congest. Since the sensor is highly sensitive to the response the moment the gas concentration reaches the minimum explosion point, the sensor would send an analog signal and then convert it from the concentration into a digital signal and then into an electrical signal. The signal can then be transmitted to the supervision center by the data transmitting unit (DTU) of the GPRS which is on guard against the explosion hazard state for all the year around. The instant the combustible gas gets to the explosion brink, the municipal sewer would in time deliver a warning signal and inform the system operator of the hazard before the explosion would occur. When the warning and location are informed of the hazard by the sensor, the system operator would send an emergency signal in-situ to dilute the gas concentration. In this way, the hazard of the gas explosion in the sewer can be expected to get avoided. The results measured in our experiments indicate that all-the-year-running successful sending rate of GPRS-DTU can reach 98.0% , with the relative defleetion error of the gas sensor reduced to below 2% . The system can thus be expected to satisfy the demands for engineering application at high reliability and stability. Furthermore, the remote-sending monitoring system can be used in different regions to achieve combined effects with the features of wide coverage , real-time online of wireless network. Thus, the construction of such a monitoring system can be said to provide an effective basis for preventing the explosion likely to be caused by the combustible gas accumulation in the municipal sewers.