Design Of Non-intrusive Leakage Monitoring System Of Pipeline Network For Enclosed Space

The pipeline network carries the transportation of materials,once the leakage is very easy to cause serious consequences.Because of space limitations,enclosed spaces are inconvenient to install a large number of instruments and wires in an intrusive manner.At the same time,in order to achieve accurate positioning of leakage points,all monitoring points are required to have high synchronization to achieve simultaneous sampling of signals.Therefore,it is of great significance and application value to develop a set of non-intrusive monitoring system for leaking pipe network that can be applied to closed space and realize data transmission in the form of wireless communication and has high signal sampling synchronization performance.In order to realize multi-nodes synchronous sampling of leakage signal in pipe network in enclosed space,a non-intrusive detection system based on wireless sensor network for pipe network leakage was designed.A magnet-adsorption non-intrusive sensing node mechanical device was designed and manufactured.The magnets placed on both ends of the flat beam were used to achieve rapid loading and unloading of the device.The horizontal standard of the acoustic wave sensor end face and the flat beam is adjusted by the thread,so that the acoustic wave sensor end face and the pipe wall are in close contact.Wireless sensor node and coordinator node with XBee Pro S3B900HP and STM32F407VGT6 as the core are designed.According to the mechanical dimensions of the sensor node,corresponding signal conditioning circuits and data acquisition/wireless transmission circuits were designed,and a coordinator circuit was designed.By analyzing the causes of clock skew in wireless sensor nodes during operation,hardware clock synchronization and software clock synchronization methods commonly used in wireless sensor network time correction techniques are compared,using the signal strength indicator(RSSI)pulse width modulation signal of the XBee module to trigger the node micro-processing interrupt response,correcting each sensor node timer,combined with the wireless timing of the GPS time,realizing the multi-node synchronous sampling hardware and software combined wireless sensor network time correction,reducing node power consumption while improving the timing accuracy of the system;The sensor node uses DMA to realize signal transmission and data wireless transmission,and triggers A/D conversion in conjunction with half-full overflow to ensure the integrity of node data packets and to ensure the accuracy of node time calibration at the same time.In the laboratory simulation an enclosed space,the stability of the system data transmission was verified by the obstacles and interference of the wall and WiFi analog data transmission.The accuracy of the system's simultaneous sampling and timing was verified by the multi-node acquisition of the same signal.A non-intrusive gas pipeline network leakage detection experiment platform was set up.The accuracy of the leakage point positioning of the leak monitoring system was verified by a manual simulated leak test.The experimental results show that the non-intrusive monitoring system for leakage of pipe network in enclosed space designed by this project has high anti-jamming capability and obstacle avoidance capability,accurate time synchronization,and high accuracy of leakage point location.It provides an effective technical measure for the early warning and monitoring of the pipeline network in an enclosed space.