Centrifugal pump is a commonly used fluid transportation equipment in industrial production, and its sealing methods mainly include mechanical seal and packing seal. This article will compare these two sealing methods from the following aspects.
First, the working principle.
Mechanical seal is the use of a pair or several of rotating shafts that are attached together, and the gap between the end faces is reduced through the rotation of the shaft to form a liquid film, so as to achieve the purpose of sealing. Mechanical seals have the advantages of small leakage, long life, and low frictional power consumption, so they have been widely used in centrifugal pumps.
Packing sealing is a sealing method that uses the friction between the packing and the shaft to prevent fluid leakage. The structure of the packing seal is simple and cheap, so it still has a certain application in some low-pressure, low-speed centrifugal pumps.
Second, the sealing effect.
The mechanical seal has a good sealing effect and small leakage, which can meet the sealing requirements of most centrifugal pumps. However, the sealing effect of packing seals is relatively poor, and the leakage is large, and the packing needs to be replaced frequently to maintain the sealing effect.
3. Service life.
Mechanical seals have a long service life, generally up to several years or even longer. The lifespan of packing seals is relatively short, generally only a few months or less.
Fourth, maintenance costs.
Mechanical seals are expensive to maintain and require regular inspection and replacement of seals. Packing seals, on the other hand, are relatively inexpensive to maintain and only require regular packing replacement.
5. Scope of application.
Mechanical seals are suitable for high-pressure, high-speed centrifugal pumps and are able to meet the requirements of most industrial production. The packing seal is suitable for low-pressure, low-speed centrifugal pumps, and also has certain applications in some special occasions.
In summary, the mechanical seal of centrifugal pump has better sealing effect, longer service life and higher maintenance cost compared with packing seal. Therefore, when choosing the sealing method of centrifugal pump, it is necessary to consider it comprehensively according to the actual situation.