Papers by Keyword: Magnetic Fluid Seal

Abstract: In order to improve the ability of magnetic fluid seals, the new structure of crossing magnetic poles on magnetic seals can be designed. The reluctivity of gap with the crossing magnetic pole is less than the reluctivity of gap without the crossing magnetic pole. The magnetic intensity in the gap can be bigger because of the crossing magnetic poles. According to the pressure formula of magnetic fluid seals, the pressure on the one side of magnetic fluid seals can be increased. The sealing capacity with the crossing magnetic pole is more than the sealing capacity without the crossing magnetic pole. The sealing capacity can be improved by 10%-15%.

Abstract: The authors put forward a new design of experimental setup in order to study the mechanism of magnetic fluid seal, and used Ansys to simulate the magnetic field distribution in the setup, the results prove its rationality. The experiment to study the way of pressure transmission has been done on the experimental setup. The experimental conclusion shows that pressure transmission is based on the recoverability of the magnetic fluid seal. When pressure exceeds the ability of the seal stage, there is a leak path in the magnetic fluid, and then the gas flows to the next stage, after that, the leak path disappears. Pressure transmits from one seal stage to the next one in this way.

Abstract: Serious problems arise when the magnetic fluid seal technology is needed to use in assemblies working in water or other liquid environment. Some efforts have been up to time made to design hybrid, two stage sealing structures with shields or mechanical seals used as protection measures to the magnetic fluid seal. Anyway, earlier or later there is always problem with direct contact between magnetic fluid and the environmental liquid. In the paper are presented results of experiments carried out with one stage rotating magnetic fluid seal operating in an direct contact with utility water. The special test procedures have been elaborated and practically used, with the aim to define main characteristics of magnetic fluid seals and to simplify experiments. These characteristics were: critical pressure, critical motion velocity and working life of the seal. Four grades of commercial, silicon based magnetic fluids of hydrophobic properties were tested in a single stage sealing system. The results of tests are presented in the form of tables and diagrams. It is concluded that hydrophobic commercial magnetic fluids could be efficiently used in rotating shaft seals however within limited and rather low range of motion velocity.

Abstract: Structure and basal application of magnetorheological fluids as well as their application in rotary shaft seals, have been presented in this study. As the application of magnetorheological fluid in seals is relatively purely known, the conducted studies were aimed at defining their operational parameters. The most essential was manner of the MR fluid delivery into oil gap, mostly the applied fluid volume. Not sufficient volume of the MR fluid often results in non-uniform oil gap filling what in turn decreases the seal efficiency. Results of studies on MR fluid-based seal burst pressure, conducted on specially designed testing stand, have been presented. The results comprise three oil gap sizes of d=0,15mm, d=0,3mm and d=0,5mm, for tests conducted with various volume of MR fluid applied on single sealing stage. Comparative values of the seal burst pressures obtained for three oil gap sizes of multi-stage seal, with the same apparent volume of MR fluid (the same fluid and oil gap volume ratio), were also presented.

Abstract: The oil seal of the high-speed non-woven loom needle spindle is a difficult problem, which has always been probed among the product manufacturer and the users. A new structure, the micro-nanon magnetic fluid seal plus the packing seal, is designed in this paper. It is suitable for the high-speed linear reciprocating spindle. The new structure is applied to the practical production. Through the productive experiments, the reliability of the structure is further optimized. So the reliability problem of the needle spindle oil seal is well solved.