Research On Test Technology Of Heating Pipeline Based On Magnetic-temperature Gradient

In recent years,with the growth of the age of heating pipelines in the north of China,there are many problems of corrosion and leakage in urban heating pipeline.It results in supplying heating difficult,and brings great economic losses to the heating enterprises.But at present,many cities in China are lack of special test equipment in the leak location of the heating pipeline.In this situation,firstly,this paper discusses the test principle of magnetic temperature gradient and analyzes the failure reason of the heat pipe,theoretically to establish the feasibility of magnetic-temperature gradient test technology of non-excavation city heating pipeline leakage in-service test.Then,the magnetic field and temperature signal of the leakage of the heat pipe are simulated by computer.It finds that the magnetic field and temperature signal are changed when the heat pipe leaks.So it is proved that it is possible to locate the leakage point by detecting the change of magnetic field and temperature signal in the case of leakage.Thirdly,in the case of lifting from the 1.5m,the weak magnetic test of the pipeline with specific notch defects is carried out.It is proved that the weak magnetic test is reliable for the leakage location of buried heat pipeline,and the locating error is less than 30 cm.And researching the magnetic-temperature gradient characteristic of three kinds of typical state of heat pipe through the computer simulation combining with the field test data of three typical states of heat pipes,the superiority of the magnetic-temperature gradient test technique in the test of heat pipes are demonstrated.On the basis of this,a set of non-excavation test instrument for heat pipeline is developed.Finally,to go to the north of the cities to carry out heat pipe field test.After the analysis,verifying the localization of the leak and excavation.The excavation results show that the heat pipeline location test instrument based on magnetic-temperature gradient test technology has high reliability for buried pipelines and open trench laying heat pipelines of the leakage location and leak point position and actual position deviation is less than 30 cm,and fully meet the actual needs of the scene.This paper provides a new test method for the leakage test of urban heat pipeline,which is the magnetic-temperature gradient difference test method combined with weak magnetic detection technology and infrared temperature measurement technology.And ithas good adaptability to complex pavement environment of buried pipelines,as well as suitable for most heating pipe leakage test.