The magnetic liquid rotary axial seal is a non-contact seal (that is, the mover and the static member are not in direct contact), and the working principle is: the closed magnetic circuit is formed by the annular permanent magnet, the magnetic pole piece and the magnetic conductive shaft, and the Yong magnetic circuit is utilized. The magnetic energy in the magnet generates a non-uniform magnetic field between the rotating shaft and the tooth gap of the pole end of the pole piece, and the magnetic liquid is tightly sucked to form a magnetic liquid "O" type sealing ring to block the gap. Thereby achieving the purpose of sealing。  

The most widely used magnetic fluids today are dynamic seals, especially for vacuum sealing, gas sealing or dust protection. For example, the vacuum sealing of the target of the x-ray diffractometer, the dust leakage of the air classification system, etc.。   

Magnetic liquid seal for applicable fields ：   
a. Dustproof seal: hard disk, airflow crushing (classification) machine, etc.。   
b. Vacuum sealing: electron microscope, electron diffractometer, CVD device, single crystal furnace, vacuum heating furnace, etc.。   
c. Gas seal: can be used in a variety of gas sealing situations (such as the gas fan shaft)。