Most of the vacuum pump flushing pipe will use the sealing medium itself from the pump inlet through the flushing pipe to introduce the sealing cavity flushing the sealing end face. Because the joint sealing gasket at both ends of the flushing pipe and the thread fit are easy to leak, sometimes the flushing fluid will erode the seal of the bellows. During maintenance, the flushing pipe will be directly removed and then the joint at both ends will be welded to death by electric welding. Without the flushing pipe, the flushing fluid will interrupt the friction pair temperature and increase, which will also shorten the service life of the mechanical seal.

 

2. Remove bellows seal guide jacket

 

      The bellows type mechanical seal generally has a water guide jacket. The cooling water enters the outside of the water guide jacket directly from the gland, and then flows out from the bottom of the sealing gland after friction. Cooling water can not only play the role of cooling friction pair, but also prevent the leakage of liquid in the sealing cavity. Vacuum pump maintenance personnel often remove the water guide jacket at will because they want to save trouble, which will cause the cooling water to flow out of the sealing gland without baffling.

 

3. Adjust the pump bearing bracket bolt when setting the alignment

 

      In the maintenance of centrifugal pump, the rotor, bearing bracket and other components into the pump shell, the gasket between the pump shell and the pump cover to adjust the axial position of the vane wheel, adjust the positioning of the pump shell and the pump cover fastening together with bolts, and then the pump cover and bearing bracket fastening together with bolts, and finally install the coupling and alignment. The motor should be adjusted when alignment, axial clearance should be adjusted first, and then radial clearance should be adjusted. Some maintenance personnel in the adjustment of the motor because it can not meet the requirements, will adjust the tightness of the fastening bolt between the pump cover and the bearing bracket to find the right, this will lead to the different fastening degree of the bolt, the electric machine will produce noise and vibration, but also cause the whole pump to scrap.

 

4. Large compression than small compression sealing effect is good

 

      In the installation of mechanical seals, many vacuum pump maintenance personnel often subjectively think that large compression is better than small compression sealing effect. However, the excessive compression of the mechanical seal leads to the excessive specific pressure of the end face, which leads to the rise of the temperature of the friction pair and the decrease of the liquid film wage of the sealing end face, resulting in the failure of the seal. But the mechanical seal compression can not be too small, the compression is too small, easy to lead to seal leakage.

 

5. Immediate maintenance is better than no maintenance

 

      Once the mechanical seal leaks in the process of use, many vacuum pump maintenance personnel think that it should be maintained in time. In fact, in some cases, the effect of immediate maintenance is not necessarily the best. In the process of mechanical seal operation, although there are some abnormalities, in fact, there is no damage, may be the change of relevant parameters such as medium, poor cooling effect and so on. After a period of time, the relevant parameters of the medium are normal.