Causes and treatment of vibration and heating of mechanical seal


Fault causes and phenomena






During the operation of the reactor, the mechanical wear and chemical erosion will make the dynamic and static rings adhere to the rough end face, and the gap between the dynamic and static rings and the sealing cavity is too small, which will cause the vibration due to the impact caused by the vibration swing.






Sometimes, the vibration and heat of mechanical seal will be caused due to the poor temperature resistance of seal face (corrosion resistance and temperature resistance), or insufficient cooling or particle impurities in the end face during installation.








Troubleshooting






If the clearance between the moving ring, the static ring and the seal cavity is too small, the inner diameter of the seal cavity shall be increased or the outer diameter of the rotation shall be reduced to ensure a clearance of at least 0.75mm.






If the friction pair is not matched properly, it is necessary to change the materials of moving ring and stationary ring to make them resistant to temperature and corrosion. This will reduce the mechanical seal vibration and heat.






Causes and treatment of mechanical seal leakage






Leakage cause of mechanical seal in static pressure test






Due to careless installation of mechanical seal, the end face of seal will often be bruised, deformed and damaged, unclean cleaning, containing granular impurities, or due to loose positioning screw, no compression of gland, insufficient accuracy of machine and equipment, so that the sealing surface does not fully fit, which will cause medium leakage. If it is shaft sleeve leakage, the shaft sleeve sealing ring is not compressed or the compression is insufficient or damaged during assembly.






Causes of periodic or paroxysmal leakage of mechanical seal






The periodic vibration and axial displacement of the rotor assembly of mechanical seal are large, which will cause leakage. The sealing surface of the mechanical seal must have a certain specific pressure, so as to play a sealing role. This requires that the spring of the mechanical seal must have a certain amount of compression, give a thrust to the sealing end face, and the reactor rotates to make the sealing surface produce the required specific pressure.






In order to ensure this specific pressure, the mechanical seal requires that the shaft should not have too much displacement, generally within 0.25mm. However, in practical application, due to unreasonable design, manufacturing error, assembly error and other reasons, the shaft often produces a large amount of channeling, periodic or paroxysmal leakage.






Causes of frequent leakage of mechanical seal






There are many reasons for frequent leakage of mechanical seal:






One is the frequent leakage caused by the defect of the seal face;






Second, frequent leakage caused by auxiliary sealing ring;






Third, leakage caused by spring defect;






Others include leakage caused by rotor vibration, leakage caused by poor quality or looseness of transmission, tightening and thrust parts, leakage caused by auxiliary mechanism of mechanical seal, frequent leakage caused by medium problems, etc.