The Study On The Magnetic Liquid Seal Of The Roots Blower

The roots blower is used as the recycle gas conveyor in the process of the methanol-to-gasoline industry. The machine main conveys the light hydrocarbon gas like C1～C4,witch has the properties of flammable and explosive. In the methanol-to-gasoline industry, the poisonous and harmful gas delivered by the blower is not allowed to leakage to avoid the production accident. A large number of roots blowers generally use labyrinth sealing or packing sealing, both of these two seals can’t meet the zero leakage. And the traditional seal can’t satisfy the requirements of zero leakage and high reliability, in order to solve these problems, a magnetic fluid seal method is used in this thesis and the structure of the roots blower is designed also. Making sure the design of the magnetic fluid seal can meet the requirements.Aiming at this goal, this thesis completes the following research works:(1)First the structure of some parts of the original roots blower was modified, and then according to the requirements of the roots blower’s working condition and the design principle of magnetic fluid seal, some parts’structures were designed,like the pole piece and the permanent magnet. In addition to these, this thesis puts forward two feasible magnetic fluid seal structure.(2)According to the related theory of electromagnetic field, magnetic field of the structure is simulated by Ansys. Distribution of magnetic field lines, the vector magnetic flux density,magnetic field strength in the gap between the shaft and the pole are obtained. Combining the theory knowledge to calculate the maximum pressure value of these two kinds of magnetic fluid seal structures, and the better sealing structures are obtained.(3)The existing experimental elements were used to do the seal pressure-resistant capacity experiment research under different gap when the shaft was rotating or stationary.Some problems occurred in the design, processing, assembly stages were discussed and solved.The static seal pressure-resistant experiment and field test experiment were done, a kind of sealing device witch can improve the reliability of the seal was designed to solve the problem occurred in the experiment. The experiment results indicate that the sealing effect of the roots blower used in the methanol-to-gasoline industry using magnetic fluid sealing is very good.In a word, the author solved the problem on the roots blower.