Misunderstanding of mechanical seal installation steps

The greater the spring compression, the better the sealing effect. In fact, the larger the spring compression, can cause the friction pair to wear rapidly and burn instantly. Excessive compression makes the spring lose its ability to adjust the end face of the moving ring, resulting in seal failure.

2. The tighter the moving ring seal, the better. In fact, it is harmful and unhelpful if the moving ring seal is too tight. 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 of the moving ring to adjust and move axially, and it cannot be adjusted in a timely manner when the working conditions change frequently; the third is that the spring is too tired and easily damaged; four It is to deform the moving ring sealing ring and affect the sealing effect.

3. The tighter the static ring sealing ring, the better. The static ring sealing ring 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 the excessive deformation of the static ring seal, which affects the sealing effect; the second is that the material of the static ring is mostly graphite, which is generally brittle, and excessive stress can easily cause cracking; the third is that it is difficult to install and disassemble, and it is easy to damage the 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 (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. 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 large shape of 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 lead to leakage between 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 be automatically locked in a timely manner, so that the shafts are always in good condition. sealed state.

5. The new one is better than the old one. Relatively speaking, the effect of using the new mechanical seal for the 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 of matching size will affect the sealing effect; In volatile and permeable media, it is better not to replace the static ring if there is no excessive wear. 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 only by adjusting the working conditions or properly adjusting the seal. This not only avoids waste, but also can verify its own fault determination ability, and accumulate maintenance experience to improve the quality of maintenance.