Several External Factors Influencing the Effect of Mechanical Seals

There are many reasons for the insufficient machining accuracy, some of which are the insufficient machining accuracy of the mechanical seal itself, which is easy to attract people's attention and find. But sometimes the machining accuracy of other parts of the pump is not enough, which is not easy to attract people's attention. For example, the enlargement accuracy of pump shaft, shaft sleeve, pump body and sealing cavity is not enough. The existence of these reasons is very unfavorable to the sealing effect of mechanical seals.

Mechanical seal

2. The second external factor affecting the mechanical seal effect: excessive vibration

The vibration of mechanical seal is too large, which eventually leads to the loss of sealing effect. However, the reason for the excessive vibration of the mechanical seal is often not the reason of the mechanical seal itself. Other parts of the pump are the source of the vibration, such as the unreasonable design of the pump shaft, the reason for machining, the insufficient bearing precision, the poor parallelism of the coupling, and the large radial force.

3. The third external factor affecting the effect of mechanical seal: large axial displacement of pump shaft

The sealing surface of the mechanical seal must have a certain specific pressure, so that it can 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 end face of the mechanical seal, and rotate to make the sealing surface produce the specific pressure required by the seal. In order to ensure this specific pressure, the mechanical seal requires that the pump shaft should not have too much displacement. The mechanical seal cannot bear the axial force during use. If there is axial force, the impact on the mechanical seal is serious. Sometimes, the axial force of the pump is not balanced due to the unreasonable design of the axial force balancing mechanism, manufacturing, installation, use and other reasons. The mechanical seal bears an axial force, and the temperature of the seal gland will be higher during operation. Polypropylene media will be melted at high temperature, so the sealing effect will be lost soon after the pump is started. When the pump is stationary, the seal face will have intermittent leakage.