A study of static magnetic fluid seal of large flange diameter

Decai Li - Xinzhi He - Zhili Zhang

School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Haidian, Beijing, 100044, P.R.China

Abstract
In order to meet the requirements of large diameter flange with regard to the leak rate, reliability and life span, the authors have designed a magnetic fluid static seal and analyzed the magnetic field distribution of the seal using three dimensional finite elements. In order to calculate correctly the theoretical differential pressure sustained by the seal, the authors reasoned the differential pressure formula of the magnetic fluid static seal so that the burst pressure of the magnetic fluid seal of large diameter flange can be calculated. In the experimental setup the authors tested the seal ability of large diameter flange and compared the theoretical values of the burst pressure with its experimental values. The authors put forward a way to prolong the life of the magnetic fluid static seal; the practical application verified that the way is effective. The authors measured the magnetic field distribution around the large diameter flange and the leak rate of the large diameter flange. The fact that the magnetic fluid static seal can be used for almost four years indicates that the seal is reliable. We have successfully developed ``the magnetic fluid seal of large diameter flange'', which was accepted as a state patent and authenticated as an achievement in the scientific research in 2003. Tables 3, Figs 7, Refs 7.