What are the mistakes in the use of mechanical seals?

Many users will choose to use according to their own ideas in the process of selecting, installing and using mechanical seals, but sometimes they do go into misunderstandings, so they will find many problems in the process of use, such as poor sealing effect and so on. So what are the misunderstandings that users are more likely to enter?
1. The greater the spring compression, the better the sealing effect
In fact, the compression of the spring is too large, which can lead to rapid wear of the friction pair and instant burnout; excessive compression makes the spring lose its ability to adjust the end face of the moving ring, resulting in the failure of the mechanical seal.
2. The tighter the dynamic ring seal, the better
In fact, too tight of the moving ring seal is harmful and unhelpful. One is to intensify the wear between the seal ring and the shaft sleeve, resulting in premature leakage; the other is to increase the resistance to the axial adjustment and movement of the moving ring, which cannot be adjusted in a timely manner when the working conditions change frequently; the third is that the spring is too fatigued and easily damaged; It is to deform the moving ring sealing ring and affect the sealing effect.
3. The tighter the static ring seal, the better
The static ring seal is basically in a static state, and the sealing effect will be better if it is relatively tight, but it is also harmful if it is too tight. One is that the sealing effect of the static ring is affected due to excessive deformation; the other is that the material of the static ring is mostly graphite, which is generally brittle, and excessive force is easy to cause fragmentation; the third is that it is difficult to install and disassemble, and it is easy to damage the mechanical seal static ring.
4. The tighter the multistage centrifugal pump impeller lock nut, the better
In the leakage of mechanical seals, the leakage between the shaft sleeve and the shaft (the leakage between the shafts) is relatively common. It is generally believed that the leakage between the shafts means that the lock nut of the impeller is not locked, and there are many factors that cause the leakage between the shafts, such as failure of the gasket between the shafts, offset, impurities in the shaft, and a large shape at the joint between the shaft and the shaft sleeve. Position errors, damage to the contact surface, gaps between the components on the shaft, and excessively long threads on the shaft head will cause leakage between the shafts. Excessive locking of the lock nut will only lead to premature failure of the inter-shaft pads. On the contrary, properly lock the lock nut so that the inter-shaft pads always maintain good compression elasticity. During operation, the lock nut will automatically lock in time, so that the shafts are always in good condition. sealed state.
5. The new is better than the old
Relatively speaking, the effect of using the new mechanical seal for the water pump is better than that of the old one, but when the quality or material of the new mechanical seal is not selected properly, the larger error in the matching size will affect the sealing effect; in polymeric and permeable media, static If the ring is not excessively worn, it is better not to replace it. Because the static ring is in a static state for a long time in the static ring seat, the polymer and impurities are deposited as a whole, which plays a better sealing effect.
6. It is better to dismantle and repair than not to dismantle
Once the mechanical seal leaks, it is urgent to dismantle and repair. In fact, sometimes the seal is not damaged, and the leakage can be eliminated by adjusting the working conditions or properly adjusting the seal. In this way, it can not only avoid waste, but also can verify its own fault determination ability, and accumulate maintenance experience to improve the quality of maintenance.
The above are some misunderstandings that machine seal users often have. When it is found that the sealing effect is not good during use, keep it and see if it has entered the misunderstanding. In addition, users should be reminded to choose appropriate products and master the neat installation and use methods when purchasing, installing and using.