Misunderstandings in the use of mechanical seals

Mistakes in the use of mechanical seals

21/03/16 16:15:03

Mechanical seal is a kind of accessory that is used more frequently now, but in the process of using the product, it is easy to use some errors to affect people's judgment, resulting in a decrease in use efficiency and damage, so for your convenience, the following Introduce the error of its use.

1. The greater the spring compression, the better the sealing effect

In fact, it is not the case. Excessive compression of the spring can lead to rapid wear of the friction pair and instant burning. Excessive compression makes the spring lose the ability to adjust the end face of the moving ring, resulting in failure of the seal.

2. The tighter the sealing pattern of the moving ring, the better

In fact, tightness of the moving ring seal is harmful and not beneficial. One is to aggravate the wear and tear between the sealing ring and the shaft sleeve and cause premature leakage; the other is to increase the resistance of the axial adjustment and movement of the moving ring, which cannot be adjusted in time 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 that the static ring seal is caused by excessive deformation, which affects the sealing effect; the other is that the material of the static ring is mostly graphite, which is generally brittle, and it is easy to cause fragmentation 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 lock nut of the impeller of the multistage centrifugal pump, the better

In the mechanical seal leakage, the leakage between the shaft sleeve and the shaft (inter-shaft leakage) is relatively common. It is generally believed that the inter-shaft leakage is that the impeller lock nut is not locked tightly. In fact, there are many factors that cause the inter-shaft leakage, such as the failure of the inter-shaft gasket, offset, impurities in the inter-shaft, and large shapes at the joint between the shaft and the shaft sleeve. Position errors, contact surface damage, gaps between parts on the shaft, and excessively long threads on the shaft head will all cause inter-shaft leakage. Excessive locking of the lock nut will only lead to premature failure of the inter-shaft pad. On the contrary, moderately lock the lock nut so that the inter-shaft pad always maintains good compression elasticity. During operation, the lock nut will automatically lock in time to keep the shaft in good condition. sealed state.

5. New is better than old

Relatively speaking, the effect of using a new mechanical seal for a 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 large error of the matching size will affect the sealing effect; Excessive wear, or not replaced. 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 role.

6. It is better to disassemble and repair than not to dismantle

Once the mechanical seal leaks, it is urgent to dismantle and repair it. 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 will not only avoid waste, but also verify your own fault judgment ability, accumulate maintenance experience and improve the quality of maintenance.

The above six aspects are the common use errors of mechanical seals. According to the use errors, reasonable use judgments can be made to better ensure the use and performance of accessories.