Mechanical seals for pumps are one of the effective methods for sealing rotating machines, which have high processing accuracy, especially for the dynamic and static rings. If the disassembly method is improper or used improperly, the installed mechanical seal will not only fail to achieve the sealing purpose but also damage the sealing components.
Leakage of mechanical seals for pumps caused by damage to the flatness of the sealing surface
The damage to the sealing surface is mostly uneven scratches and surface cut marks. The cause of the damage may be that the sealing box of the pump and the seal head of the agitator are deformed or damaged, or the bolt tightening force is uneven, which causes the sealing surface of the static ring to deform, resulting in leakage. It may also be due to the change in the shape of the sealing surface caused by the temperature change during the hot assembly of the sliding parts and the existence of thermal expansion differences. The sealability will also be damaged, which will cause leakage problems.
Leakage of mechanical seals for pumps caused by damage to the lubricity of the sealing surface
The lubricity of the end face seal is also very important. In addition to relying on the end face liquid film for sealing, it also relies on lubrication to complete normal operation. Once the end face liquid film is damaged, it will cause instantaneous wear and roughness of the sealing surface due to dry friction, and even some hard materials will produce serious phenomena such as cracks. When the temperature of the sliding friction surface suddenly rises and the thermal accumulation situation cannot be immediately removed, it will cause the evaporation of the sealing liquid, the disappearance of the lubricating film, and then the occurrence of dry friction phenomenon. Dry friction can easily damage the sealing surface and bury a large number of leakage hazards.
Leakage of mechanical seals for pumps caused by dynamic damage
The dynamic ring and the static ring of the pump mechanical seal device are always rotating with the shaft, and two mechanical seal rings are always performing the same repetitive movement, which not only changes the sealing end face but also increases the axial movement of the device and gradually reduces the accuracy of the mechanical seal. In this way, over time, various parts of the device will be damaged or deformed, and the follow-up ability will be lost, resulting in leakage of the seal.
What conditions will affect the dynamic performance of the mechanical seals for water pumps? Firstly, the accumulation of slurry will hinder the action of the spring, cause the sliding parts to lose control, and cause wear on the outer surface of the sealing surface, severely affecting the dynamic performance of the mechanical seal. When the sliding seal surface experiences wear, hardening, and aging, the shaft and sleeve will be damaged, and the spring seat will also wear or even bend.
Many of these reasons are caused by excessive fatigue, uneven compression, and liquid film damage. Therefore, correct installation and maintaining the cleanliness of the pump mechanical seal are very important, coupled with good cooling effect, which can better eliminate hidden dangers.