Flushing pipe

The flushing pipe of vacuum pump mostly uses the sealing medium itself to flush the sealing end face through the flushing pipe through the pump inlet. Because the joint gasket and thread fit at both ends of the flushing pipe are easy to leak, and sometimes the flushing fluid will erode the seal of the bellows, the flushing pipe shall be removed directly during maintenance, and then the joints at both ends shall be welded with electric welding. Without the flushing pipe, the flushing fluid will be interrupted, the temperature of the friction pair will also be increased, and the service life of the mechanical seal will be shortened.

2. Remove the bellows sealing water guide sleeve

Generally, bellows type mechanical seals are equipped with water guide sleeve. The cooling water enters the outside of the water guide sleeve from the top of the gland and flows out from the bottom of the gland after friction. The cooling water can not only cool the friction pair, but also prevent the liquid leakage in the sealing cavity. In order to reduce the trouble caused by dredging the cooling water path, the vacuum pump maintenance personnel often remove the water guide sleeve at will because of saving trouble, which will cause the cooling water to flow out of the sealing gland without baffling.

3. Adjust the bearing bracket bolts of the pump when aligning

When repairing the centrifugal pump, install the rotor, bearing bracket and other components into the pump housing, adjust the axial position of the impeller with the gasket between the pump housing and the pump cover, after adjustment, fasten the pump housing and the pump cover with bolts, then fasten the pump cover and the bearing bracket with bolts, and finally install the coupling and align. When adjusting the motor, adjust the axial gap and adjust the radial gap. When adjusting the motor, some maintenance personnel will adjust the tightness of the fastening bolts between the pump cover and the bearing bracket to make alignment because they can't meet the requirements. This will lead to the noise and vibration of the motor and the scrapping of the whole pump due to the different tightness of the bolts.

4. Large compression is better than small compression

In the installation of mechanical seals, many vacuum pump maintenance personnel tend to subjectively think that large compression is better than small compression. However, the excessive compression of the mechanical seal results in the excessive specific pressure of the end face, which leads to the increase of the temperature of the friction pair and the decrease of the liquid film thickness of the seal end face, resulting in the failure of the seal. But the mechanical seal compression should not be too small, too small compression, 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 repaired in time. In fact, in some cases, the immediate repair effect is not necessarily the best. In the process of mechanical seal operation, although there are some abnormalities, there is no damage in fact, it may be the change of medium and other related parameters, poor cooling effect and so on. After a period of time running, the media related parameters are normal.