Locating method and system for city gas pipeline leakage test

Abstract

The invention relates to a novel leakage detecting-positioning method of urban natural gas pipelines and a system thereof. An infrared laser device, a laser device temperature and current controller and a signal generator are arranged in a case. A light outlet of the infrared laser device is positioned at the front end of a light inlet window sheet of a multiple-reflection absorbing pool, wherein, an air outlet of the multiple-reflection absorbing pool is connected with a micro suction pump, and an air inlet thereof is connected with a hose. The end of the hose is connected with a sampling probe. An exhaust port of the micro suction pump is communicated with the atmosphere out of the case. The laser entering the multiple-reflection absorbing pool is radiated out from the light outlet window sheet of the multiple-reflection absorbing pool and received by a laser detector. A signal output of the laser detector conducts a signal treatment. The sampling probe adopts air suction type sampling so as to lead the detection to be more flexible and convenient as well as provide high resolution. By adopting a laser spectrum technology which reacts to CH4 only, the detection limit reaches one part per million (PPM) level and the fine change of the density of the CH4 gas around a leakage point caused by the leakage of the natural gas pipeline can be detected.

Description

technical field [0001] The invention relates to the field of environmental spectroscopy and the technical field of detection and positioning of gas pipeline leakage, in particular to a tunable laser spectrum technology (TDLAS) based CH for detection and positioning of urban natural gas pipeline leakage. 4 Gas concentration measuring system and method. technical background [0002] At present, as one of the essential infrastructures of cities, gas pipelines have made great contributions to the improvement of people's living standards. However, due to the aging of pipeline equipment, the influence of geographical and climatic conditions, and man-made sabotage, leakage accidents often occur. Once the urban gas pipeline leaks, it will not only bring economic losses and environmental pollution, but also cause fires and explosions due to the many uncertain fire sources in the city, causing casualties and other catastrophic accidents, which will have a huge negative impact on soci...

AI Technical Summary

Problems solved by technology

[0005] In the existing technology, there is also an open natural gas leakage monitoring method based on tunable semiconductor laser absorption spectroscopy technology. Although the sensitivity of large-scale natural gas leakage monitoring has been improved, this method adopts an open optical path structure and is not suitable for complex cities. Leak detection and location of natural gas pipelines in ground environment

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