Research On Magnetic Flux Leakage Detection Automatic Walking Device Of Tank Floor

Corrosion and leakage of storage tank floor in petrochemical industry is a serious problem,which poses a great threat to property and life safety.Magnetic flux leakage detection is a common method for detecting the bottom plate of storage tank.It can detect the floor of the tank in large area.However,it is very important for the inspectors to develop an automatic detection device.According to the repair regulations of vertical cylindrical steel welded raw oil tank,many corroded tank floors will be repaired with patch plates,and the detection of the re corrosion of the patch is rarely reported at home and abroad.It is urgent to develop the three-dimensional spatial distribution characteristics of the leakage magnetic field of the tank floor patch plate and influence the factors of the factor analysis.In this paper,magnetic flux leakage testing technology for tank floor is studied.The distribution rule of characteristic components of leakage magnetic field of different types of defects is obtained.The magnetic flux leakage testing instrument with fixed magnetization structure is used to detect the bottom plate of storage tank.It is proved that the fixed magnetic structure detector is not suitable for detecting the bottom plate of storage tank.Finite element software is used to simulate and analyze the optimal air gap distance of different thickness of plates,and the best fitting curve of air gap distance suitable for different thickness detection is obtained.The influence of plate thickness,gap,defect position,defect depth and air gap distance on the spatial distribution characteristics of leakage magnetic field are obtained.According to the simulation law,the lifting distance of the magnetized structure is refined,the design of the instrument is completed,and the functions of automatic detection,cross plate detection,patch testing and small space detection are realized.Experiments on different plate thickness of different plate thickness steel plate for simulating storage tank floor.The results show that the designed instrument can detect the bottom plates of different thickness plates.The experiment made the relative defects of the simulation and simulation,and set the conditions of different plate thickness,different plate gap,different defect position,different defect depth and different air gap distance.The magnetic flux leakage test of tank bottom plate is carried out separately,and the experimental results are consistent with the finite element simulation results.Under the laboratory conditions,the motion function of the automatic walking device for detecting the floor leakage of the tank floor is simulated,and the relative error of the straight line walking is obtained.According to this,a route planning method adapted to the detection process of different length storage tanks is designed.