Magnetic fluid seal precautions

1. In the initial stage of use of the magnetic fluid seal, if a small amount of magnetic fluid is found to overflow, but the vacuum can be maintained, the general sealing effect is not affected. This is because it is difficult to control the amount of filling when filling the magnetic fluid. Once the filling is excessive, the excess magnetic fluid is pumped away until the proper amount is maintained. The relationship between the amount of magnetic fluid injection and the withstand voltage is: increase the amount of injection of magnetic fluid at the beginning, and the withstand voltage increases substantially linearly. However, after the injection amount reaches a certain value, the withstand voltage no longer increases, but is stable. In a constant state。

2. When using the magnetic fluid seal for the first time, the vacuuming time should be extended appropriately to remove all the components inside the magnetic seal that are not conducive to vacuum. If the other seals of the equipment system are not problematic, vacuum again. , the vacuum will rise quickly。    

3. When designing the structure of the magnetic fluid seal, attention should be paid to the material selection of the components of the magnetic fluid seal, the structural design calculation of the pole shoe profile, the selection of the seal gap between the pole piece and the shaft, and the determination of the withstand voltage series. Reasonable design calculation and calibration calculation of magnetic circuit, relative position of bearing assembly and magnetic core, etc.。      

4. When the magnetic fluid seal is processed, it is necessary to take appropriate technological measures to ensure the dimensional tolerance and shape tolerance of the design, and use appropriate detection methods for inspection.。

(1) When installing a magnetic fluid seal with no bearing inside, ensure that the shaft or magnetic sleeve does not touch the pole piece assembly, preferably a relatively uniform amount of clearance; a magnetic fluid seal with a bearing inside the installation When ensuring that the bearings in the main bearing and the magnetic fluid seal do not interfere with each other. In other words, to ensure a certain degree of coaxiality requirements。  

(2) When the magnetic fluid seal is suspected to be faulty, the internal components of the magnetic fluid seal cannot be dismantled at will to avoid unnecessary damage.。  

(3) When the magnetic fluid seal is used for vacuum sealing, care should be taken not to drop acetone, ethanol, acid, alkali, water, non-vacuum oil and other solvents into the magnetic fluid seal to avoid sealing failure。  

5. After the equipment has been parked for a long time, if the power to drive the magnetic fluid seal is relatively small, the rotating shaft of the magnetic fluid seal should be rotated for several weeks before restarting the work, and then the power is turned on。  

6. When the temperature rises, the pressure resistance of the magnetic fluid seal decreases. Considering the influence of temperature, the linear velocity of the surface of the shaft should be controlled below 20m/s. If the temperature of the sealing portion is higher than 80 ° C or the linear velocity of the magnetic fluid axis exceeds 20 m / s, cooling treatment is required to control the temperature within a certain range. Before the magnetic fluid seal with water cooling device is working, the cooling water should be connected before the rotation can be started to avoid the seal failure caused by overheating within a certain period of time。     

7. For high-speed rotating shafts, the influence of centrifugal force on magnetic fluid can not be ignored, and corresponding measures should be taken in the structural design of the sealing assembly。

8. When the magnetic fluid seal is processed, appropriate process measures must be taken to ensure the dimensional tolerance and shape tolerance of the design, and the appropriate test method is used for inspection。