Method for detecting abnormality of underground heat pipe network by infrared thermography coupling soil temperature/humidity

Abstract

The invention relates to a method for detecting the abnormality of an underground heat pipe network by infrared thermography coupling soil temperature / humidity. In the direction of an underground pipe network, the surface temperature of a direct burial heat pipe is detected; four infrared thermography images are shot; and according to the area and temperature change of a temperature abnormal region, a surface temperature abnormal region is positioned. For a region with an insulation layer damage or leakage fault, a soil temperature and humidity sensor is used for measuring and recording the soil temperature and the volume water content. Higher temperature gradient shows in the vertical direction; when the change tendency of the volume water content of the soil at the lower part of the surface temperature normal / abnormal region along with the depth is consistent, but the soil water content of the abnormal region is slightly higher than that of the normal region, it is judged that an insulation layer of the underground pipe network is damaged; and if the temperature and volume water content changes of underground soil in the two regions are prominently different along with the depth, the surface temperature abnormal phenomenon indicates the leakage of the underground pipe network. The method can accurately position the leakage point of the heat pipe and the damage point position of the insulation layer to instruct maintainers for repair, reduces blind excavation of pavements, and improves the repair efficiency.

Description

technical field [0001] The invention relates to a method for detecting the abnormality of a buried thermal pipe network by coupling the infrared thermal image with the soil temperature and humidity, specifically a method for judging the leakage of the directly buried thermal pipe network or the damage of the insulation layer by using the infrared thermal image technology coupled with the soil temperature and humidity detection method . The invention can accurately locate the leakage point of the thermal pipeline or the damaged point of the insulation layer, guide the pipeline maintenance personnel to excavate and repair the area, reduce the loss caused by blind excavation of the road surface, and improve the repair efficiency. Background technique [0002] Since the direct burial laying has the advantages of small investment, fast construction progress, less land occupation and easy coordination with other underground pipelines and facilities, the heating pipe network is oft...

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Problems solved by technology

[0004] The detection of direct buried heating pipe network usually adopts the manual inspection method, through direct observation and the use of "point temperature gun" to detect the surface condition of the laying surface of the heating pipe network to locate the leakage point of the heating pipe network and the damage point of the insulation layer. However, this method only It is suitable for detecting pipeline faults with large abnormality of ground surface temperature, damaged insulation layer or abnormally serious leakage, and it is difficult to realize real-time detection of faults in the entire thermal pipe network

In "Research on Fault Diagnosis Methods of Thermal Networks", Zhao Kai introduced an isolation detection method for thermal pipeline network leakage, closing the valves of some pipeline sections to isolate the corresponding pipeline sections from the entire heating network, and observing the changes in water supply and water pressure. situation, to determine whether the isolated pipe section is leaking; however, this method can only determine whether there is a leakage fault in the isolated pipe section, but cannot accurately locate the leak point

Shan Lijun introduced a sound and vibration detection method for heat pipe network leakage in "Discussion on Leakage Detection Methods of Heating Pipelines", that is, using listening sticks, leak detectors and other equipment to monitor the sound signals generated when the pipelines and fittings in the well leak. Then determine whether there is a leak, and then manually judge the distance between the leak point and the detection point; however, this method requires a high degree of experience of the staff, the detection signal is easily interfered by background noise, and it is difficult to accurately determine the location of the leak point

In "Infrared thermal imaging technology applied to thermal pipe network insulation and leakage detection technology research", Li Huizeng proposed a detection method along the direction of direct buried pipelines, using infrared thermal imaging cameras to capture surface temperature, and included surface temperature anomalies at the same time through comparative analysis Infrared thermal images of the direct-buried thermal pipeline and the normal temperature zone can be used to determine the leakage of the direct-buried thermal pipeline or the damage of the insulation layer. This method can intuitively and quickly locate the fault location of the direct-buried thermal pipeline network, but it is difficult to distinguish and judge the thermal Is the pipe network leaking or the insulation layer is damaged?

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