Misunderstandings in the Maintenance of Double Suction Pump Mechanical Seals


Published:

Mar 06,2024

The following are several misunderstandings in the maintenance of double-suction pump mechanical seals.

Misunderstandings in the Maintenance of Double Suction Pump Mechanical Seals

The following are several misunderstandings in the maintenance of double-suction pump mechanical seals.

1. The greater the spring compression, the better the sealing effect. In fact, if the compression amount of the spring is too large, it can cause the friction pair to wear rapidly and burn out instantly; excessive compression causes the spring to lose its ability to adjust the end face of the moving ring, resulting in seal failure.

2. The tighter the dynamic ring sealing pattern, the better. In fact, too tight a dynamic ring seal is harmful rather than helpful. First, the wear between the sealing ring and the sleeve is aggravated; second, the resistance to axial adjustment and movement of the moving ring is increased, making it impossible to adjust in time when working conditions change frequently; third, the spring is easily damaged due to excessive fatigue; fourth, the moving ring is The sealing ring is deformed, affecting the sealing effect.

3. The tighter the static ring sealing ring, the better. The static ring sealing ring is basically in a static state. A relatively tight sealing ring will have a better sealing effect, but being too tight is also harmful. The first is that the static ring seal is excessively deformed, which affects the sealing effect; the second is that the static ring is mostly made of graphite, which is generally brittle and can easily cause fragmentation due to excessive stress; the third is that it is difficult to install and disassemble, and the static ring is easily damaged.

4. The tighter the impeller lock nut, the better. Among mechanical seal leaks, leakage between the sleeve and the shaft (inter-shaft leakage) is relatively common. It is generally believed that inter-shaft leakage means that the impeller lock nut is not locked. In fact, there are many factors leading to inter-shaft leakage, such as failure and offset of the inter-shaft pad, impurities in the shaft, and large shapes at the joint between the shaft and the shaft sleeve. Position error, damage to the contact surface, gaps between components on the shaft, excessive thread length of the shaft head, etc. will all lead to leakage between shafts. Excessive locking of the lock nut will only lead to premature failure of the inter-axle pad. On the contrary, lock the lock nut appropriately so that the inter-axle pad always maintains a certain compression elasticity. During operation, the lock nut will automatically lock in time to ensure that the inter-axle pad is always in good condition. sealing status.

5. New ones are better than old ones. Relatively speaking, the effect of using a new mechanical seal is better than that of the old one. However, when the quality or material selection of the new mechanical seal is inappropriate, the large error in matching dimensions will affect the sealing effect; in polymeric and permeable media, if the static ring is not excessively If it is worn out, 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 into one body, which plays a better sealing role.

6. It is better to dismantle and repair than not to dismantle. Once a mechanical seal leaks, there is a rush to dismantle and repair it. In fact, sometimes the seal is not damaged, and the leakage can be eliminated by adjusting the working conditions or adjusting the seal appropriately. In this way, you can avoid waste and verify your fault judgment ability, accumulate maintenance experience and improve the quality of maintenance.

Keyword:

Double Suction Pump,Mechanical Seal