1. One of the external factors affecting the effect of mechanical seal: insufficient machining precision

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

2. The second external factor that affects the effect of mechanical seals: excessive vibration

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

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

The sealing surface of the mechanical seal must have a certain specific pressure, so that it can play a sealing role, which requires that the spring of the mechanical seal must have a certain amount of compression, give a thrust to the end surface of the mechanical seal, and rotate to make the sealing surface produce the required sealing force. Specific pressure. In order to ensure this specific pressure, the mechanical seal requires that the pump shaft cannot have too much movement. The mechanical seal cannot bear the axial force during use. If there is an axial force, the impact on the mechanical seal will be serious. Sometimes due to the unreasonable design of the axial force balance mechanism of the pump and the reasons of manufacture, installation and use, the axial force is not balanced. The mechanical seal bears an axial force, and the temperature of the sealing gland will be high during operation. For polypropylene medium, it will be melted at high temperature, so the sealing effect will be lost soon after the pump is started, and the sealing end surface will appear when the pump is stationary. intermittent leaks.

4. The fourth external factor affecting the mechanical seal effect: no auxiliary flushing system or unreasonable setting of auxiliary flushing system

The auxiliary flushing system of the mechanical seal is very important. The auxiliary flushing system of the mechanical seal can effectively protect the sealing surface, play the role of cooling, lubricating, and washing away sundries. Sometimes the designer does not configure the auxiliary flushing system reasonably, and the sealing effect cannot be achieved; sometimes, although the designer designs the auxiliary system, there are impurities in the flushing liquid, the flow and pressure of the flushing liquid are not enough, and the location of the flushing port is unreasonably designed, etc. , also can not achieve the sealing effect.