| Thermal pipeline plays an important role in people's heating in winter.It is of great significance to ensure the safe operation of thermal pipeline.With the years of operation,the thermal pipeline will produce different degrees of corrosion.How to ensure the safe operation of the thermal pipeline is an urgent problem to be solved.At present,there are few technologies and instruments used in thermal pipeline corrosion leakage detection.In this paper,a thermal pipeline detection technology based on transient electromagnetic method is proposed,which can effectively detect the corrosion of the pipeline.However,because the thermal pipeline is laid under the complex urban road surface,there are many interference factors,which affect the detection effect.It is of great significance to study and analyze the interference factors,distinguish the signals and summarize the influencing rules,which will improve the effect of corrosion detection of pipes.Firstly,this paper introduces some theoretical foundations of TEM,expounds the principle of TEM detection combined with basic theory,studies and analyses the characteristics of induced voltage of TEM,and points out the characteristics of TEM detection.According to the relationship between the residual wall thickness of the thermal pipeline and the normalized induced electromotive force,the mathematical model of the calculation of the residual wall thickness is established,and the three factors of the failure of the thermal pipeline are studied and analyzed.Secondly,the transient electromagnetic detection system is designed.Choose reasonable excitation signal and sensor type,and get the best value of external damping resistance through theory combined with experiment.The coil sensor is designed.The parameters of the coil sensor are determined by experiments.The magnetic core of the coil sensor is studied.The gain effect of adding ferrite core to the coil sensor is analyzed.According to the residual wall thickness algorithm,the software for wall thickness inversion is compiled.Thirdly,combined with the actual working conditions of thermal pipeline,the interference factors of transient electromagnetic method for thermal pipeline detection are analyzed.The interference effects of buried depth and inclination of pipeline are analyzed through experiments.The relationship between induction electromotive force and them is fitted and summarized.The characteristic signals ofthermal pipeline compensator and cross-pipe are analyzed and compared,and the characteristic signals and interference degree are summarized.Finally,the process of on-site inspection is summarized.Through the application of on-site engineering inspection,the wall thickness corrosion error is less than 10%.It is further verified that TEM is a good detection technology for thermal pipelines. |
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