Flexible Pole Piece Magnetic Fluid Sealing Device

Abstract

A flexible pole piece magnetic fluid sealing device belongs to the field of mechanical engineering sealing. It mainly includes casing (1), end cover (3), permanent magnet (5), flexible pole shoe (6), soft iron (7), front plate (8), back plate (9), shaft sleeve (11) and Parts such as coating (12). When the flexible pole piece magnetic fluid seal device works, the magnetic induction line starts from the permanent magnet, passes through soft iron, flexible pole piece, coating and shaft sleeve to form a magnetic circuit. The magnetic fluid gathers and adsorbs around the flexible pole piece between the baffle plate and the surface of the rotating shaft and in the gap, and plays the role of bearing the axial pressure of the sealing medium and blocking the leakage channel of the medium, thereby realizing the sealing function.

Description

technical field [0001] The invention belongs to the field of mechanical engineering sealing, in particular to a magnetic fluid sealing device. technical background [0002] When solving the problem of large-diameter spindle seals in some large-scale petrochemical equipment and marine machinery, the seal of the rotating shaft directly affects the stability of the overall operation of the mechanism. It can be said that the sealing technology is usually the key factor that determines whether a certain major technology can be fundamentally realized. . The traditional sealing form has advantages and disadvantages: the packing seal structure is simple, but the sealing ability is insufficient, the service life cycle is short, and the packing needs to be replaced regularly, causing a series of related complex problems such as assembly; the mechanical seal has good sealing performance, and the seal is pressure-bearing. The capacity is high, but under the condition of large diameter,...

AI Technical Summary

Problems solved by technology

[0004] In general, in order to ensure the pressure resistance and reliability of the ferrofluid seal, the sealing gap should be selected as small as possible in the design of the sealing device. However, in practical applications, the small sealing gap will bring many problems: first , the sealing gap is constrained by the radial runout of the rotating shaft. If the sealing gap is too small, it is easy to cause bumps between the rotating shaft and the pole teeth, and even the phenomenon of "shaft holding" of the pole teeth occurs. This not only affects the performance of the magnetic fluid seal, but also causes The failure and destruction of the seal, at the same time, the small sealing gap also brings great difficulty to processing and assembly; secondly, in the dynamic seal, the smaller sealing gap will bring greater shear rate, so the magnetic fluid The frictional heat generated is also greater, especially under the condition of large diameter, the friction caused by the circular runout will also cause the local temperature to rise, and the stability and service life of the magnetic fluid will also be reduced accordingly.

While solving the problems and defects of the original ferrofluid sealing device, this device also has its own shortcomings: it is very difficult to manufacture and assemble the seal composed of bristles of different lengths; Magnetic flux leakage will weaken the magnetic field strength around the brush filaments and reduce the sealing performance; the long bristle bundles directly contact the surface of the rotating shaft, and long-term operation will cause wear to the rotating shaft, and the premise of sealing is to form a magnetic circuit, that is, the rotating shaft must be a guide Magnetic material, which further limits the application of the seal

Images