Several misunderstandings in the maintenance of mechanical seals

1. The greater the tension of the spring, the better the sealing effect. In fact, it is not the case. Excessive tightening of the tension spring can cause rapid wear and tear of the friction pair and instant burning; excessive tension makes the tension spring lose its ability to adjust the end face of the moving ring, resulting in seal failure. 2. The tighter the sealing ring of the moving ring, the better. In fact, too tight of the moving ring seal is harmful and unhelpful. One is to increase the wear between the sealing ring and the shaft sleeve, resulting in premature leakage; the other is to increase the resistance of the moving ring to adjust and move axially, and it cannot be adjusted when the working conditions change frequently; the third is that the tension spring is too fatigued and easily damaged ; The fourth is to deform the moving ring sealing ring, which affects the sealing effect. 3. The tighter the static ring seal, the better. The static ring seal is basically in a stopped 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 static ring seal is excessively deformed, which affects the sealing effect; the second is that the static ring material is mostly graphite, which is generally brittle, and it is easy to break due to excessive force; the third is that it is difficult to install and disassemble, and it is easy to damage the static ring. 4. The tighter the impeller lock nut, the better. Among the leakage of mechanical seals, the leakage between the shaft sleeve and the shaft (inter-shaft leakage) is relatively common. It is generally believed that the leakage between the shafts means that the lock nut of the impeller is not locked. In fact, there are many factors that cause the leakage between the shafts, such as the failure of the gasket between the shafts, the offset, the impurities in the shaft, and the cooperation between the shaft and the shaft sleeve. Shape and position errors, damage to the touch 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 cause the inter-shaft pad to fail prematurely. On the contrary, properly lock the lock nut so that the inter-shaft pad will always maintain a certain compression elasticity. Outstanding sealing condition. 5. The new is better than the old. Relatively speaking, the sealing effect of mechanical seals is better than that of the old ones, but when the quality or material of the new mechanical seals is not properly selected, a large error in the working scale will affect the sealing effect; in polymeric and permeable media, static If the ring is not excessively worn, it is still better not to replace it. Because the static ring is in a stopped state for a long time in the static ring seat, the polymer and impurities are deposited as a whole, which has a good sealing effect.