The Study Of Magnetic Flux Leakage Technology For The Inspection Of Tank Floors

Tank floor is made of ferromagnetic material, however, due to their operation in the condition of the change of environment and medium height all the year round, they inevitably suffer from various damnification and other factors. Especially corrosion perforation, crack expanding and rive and so on by chemical corrosion and electrochemistry corrosion make medium leak and cause serious disaster and environment pollution. This is a big economic loss to the state economy. Therefore, it must be inspected at intervals of several years. Anciently, oil field in our country always uses to inspect by hand, it has big labour intensity, long inspection time, and reject servicing is lack of science. Especially there are no good methods to inspect the corrosion of tank floor underside. Recently, with the development of the hard ware technology of computer and theory of non-destructive testing (NDT) methods, it is possibly to intellectualized inspect tank floor.The usual methods to inspect tank floor are ultrasonic testing (UT). eddy current testing (ET). magnetic particle testing (MT) and magnetic flux leakage (MFL). We compare the methods to each other on inspecting tank floor, try to find the optimum method to inspect tank floor, and develop apparatus to inspect tank floor with magnetic flux leakage. So that we can inspect tank floor with high effect and scientific manage tank.This paper aims at the fact to inspect tank floor in the field, chooses magnetic flux leakage technology for the inspection of tank floor as research object. Develop the object in order to inspect tank floor and estimate corrosion expediently and fleetly.Develop magnetic flux leakage technology for the inspection of tank floor, the main work is build mathematical modal of tank floor under magnetization. According to the thickness of tank floor % resistance radio , specific magnetism and characteristic of magnetic field leakage, work out a series of technical key parameters needed at perfect status. Such as the intensity of magnetization size of magnetic field leakage and so on. According to the designed intensity of magnetization, and think about trying to lighten instrument's volume and weight whole hog, we choose Nd-Fe-B permanent magnet as magnetizer. According to the size and characteristic of magnetic field leakage, select appropriate sensors with high sensitivity radio, and select corresponding circuit for data collection, filter the waves and magnify. On the base of these works, we organize a relatively simple system for inspection (four channels) in lab, and then work out corresponding software for data collection and analysis. To examine the equipment that we designed is reasonable and feasible, we do plentiful experimentation with it. On the base of the first stage of research, we develop magnetic instrument with 24 channels to inspect tank floor. We work out the software of it for data collection and analysis. The software can carry out the wave of data at actual time, and result figure of inspection visible. It makes identify and analyse disfigurement more easy and reliable. In lab We do plentiful experimentation using man-made simulative cone-shaped disfigurement of tank floor. It proves that magnetic instrument with 24 channels to inspect tank floor has veracity and reliability. With it, we analyse the influence to sensitivity radio of inspection with a great variety of effectible factors, such as lift values speed of inspections thickness of coats intensity of magnetizations roughness of tank floor surface and fragments of ferromagnetic material and so on. And we take out the methods to solve the factors. We constantly ameliorate the software and hardware of the instrument to make sure that it can be use in field. These have important meaning to guide tank floor inspection with magnetic flux leakage technology.