COMMON FAILURES OF MECHANICAL SEALS

Mechanical seals are widely used in rotating equipment. The sealing effect of mechanical seals will directly affect the operation of the machine, and serious safety accidents will occur.

Common Faults of Mechanical Seal

1. Mechanical Seal Parts Failure

Due to inattentiveness of the mechanical seal during installation, the seal end face is often deformed, damaged or containing granular impurities. Or due to loose positioning screws, 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, maybe the shaft sleeve sealing ring is not compressed or the compression is insufficient or damaged during assembly.

2. Excessive Vibration of Mechanical Seal

Excessive vibration of the double mechanical seal will eventually lead to loss of sealing effect. However, the reason for the excessive vibration of mechanical seal is not only the mechanical seal itself, but also other parts of the pump, such as unreasonable design of pump shaft, processing reasons, insufficient bearing accuracy, poor parallelism of coupling, large radial force and other reasons.

Measures Taken to Deal with Faults

1. Treatment of Mechanical Seal Parts Failure

If the parts of the mechanical seal fail, it is necessary to replace the parts or improve the machining accuracy of the parts. Improving the machining accuracy of the water pump mechanical seal are very beneficial to the effect of the mechanical seal. In order to improve the sealing effect, the requirements for the smoothness and unevenness of the friction surface of the dynamic and static rings are higher. The width of the friction surface of the dynamic and static ring is not large, generally between 2 and 7 mm.

2. Treatment of Vibration and Heating of Mechanical Seal

If the gap between the dynamic and static ring and the seal cavity is too small, it is necessary to increase the inner diameter of the seal cavity or reduce the outer diameter of the rotation to ensure a clearance of at least 0.75 mm. If the friction pair is not paired properly, the dynamic and static ring materials must be changed to make it resistant to temperature and corrosion. This can reduce the vibration and heat generation of the mechanical seal.

3. Treatment of Mechanical Seal Leakage

The leakage of mechanical seal is caused by many reasons. In order to minimize the leakage, the mechanical seal must be installed in strict accordance with the technical requirements of the assembly, but also pay attention to the following:

(1) The assembly shall be clean and smooth. Parts, tools and instruments, lubricating oil and wiping materials of mechanical seal shall be clean. The sealing end face of the dynamic and static ring shall be wiped with soft gauze.

(2) The chamfers of the shaft and the sealed end cover shall be trimmed smoothly, and the relevant rounded corners of the shaft and the end cover shall be sanded and polished.

(3) When assembling the auxiliary sealing ring, the rubber auxiliary sealing ring cannot be soaked and washed with gasoline or kerosene to avoid swelling and deformation and premature aging. After the dynamic and static ring is assembled, press the compensation ring by hand to check whether it is in place and flexible, whether the elastic split ring is positioned reliably. After the dynamic ring is installed, it must be ensured that it can move flexibly in the axial direction on the shaft.

If you're interested in reducing pump seal failures, take a look at all phases of equipment application – how is the sealed equipment specified, installation practices, all the way up to operations.