Research On The Infrared Thermographic Inspection Technique For Leakages Of Heating Network

If the leakages of buried heating network can’t be located timely and accurately,the leakage accidents of buried heating network would lead to huge economic loss and energy waste.As a result,the thermal users wouldn’t keep their houses warm in the winter.Therefore,it is of greatly actual significance to study and develop a fast,accurate and practical inspection technique of leakages for the buried heating network.In this paper,we used the empirical study combined with qualitative analysis method to research an inspection technique of infrared thermography coupled with the temperature and moisture of soil for the leakages of buried heating network.And this work relied on the buried heating network system of downtown Chengde.This paper proposed a method of detecting infrared thermography coupled with the temperature and moisture of soil for the leakage and damaged insulation layer of buried heating network against the defects of existing inspection techniques.Based on the temperature and moisture of soil which is around the heating pipe,this paper discussed whether it is feasible to detect infrared thermography coupled with the temperature and moisture of soil for the failures of buried heating network.This paper arranged the actual detection cases which are about the fast positioning for the leakages of buried heating network.The results show that the abnormal temperature zone located by infrared thermal imager and in the surface which is above the leaking pipe is the position of leakage.In this paper,the actual case detected by the method of detecting infrared thermography coupled with the temperature and moisture of soil and about damaged insulation layer of the heating pipe was analysed.The results show that: The temperature distribution in the abnormal temperature zone of surface which is above the pipe slightly changes with time;The soil temperature under the abnormal temperature zone of surface significantly increases with the depth,and the amplitude is far greater than the soil temperature under the normal temperature zone of surface;There is no abnormal fluctuation in the volumetric water content of soil under the abnormal temperature zone of surface and the normal temperature zone of surface.In this paper,the actual case detected by the method of detecting infrared thermography coupled with the temperature and moisture of soil and about leakage of the heating pipe also was analysed.The results show that: The area of the abnormal temperature zone of surface which is above the pipe increases with time;Under the same climate conditions and time point,the overall temperature of the abnormal temperature zone of surface increases with time;The temperature and volumetric water content of soil under the abnormal temperature zone of surface and normal temperature zone of surface are completely different in the variation of depth;The temperature and volumetric water content of soil near the pipe which is below the abnormal temperature zone of surface don’t change with the depth.Finally,the working process of inspection technique of infrared thermography coupled with the temperature and moisture of soil for leakages of heating network was summarized.