Mechanical seal is a dynamic seal used in rotation, also known as end face seal. To the wear compensation mechanism. Of course, the definition or terminology of mechanical seals may change with the development of mechanical seals. For example, mechanical seals with tapered end faces have appeared, and various types of bellows mechanical seals have been popularized and used, and the meaning of auxiliary seals will also be extended. Although the structure of mechanical seal is varied, its working principle is basically the same. The working principle of the mechanical seal is to use two sealing surfaces that fit each other, flat and perpendicular to the rotation axis, and rotate relative to each other. It relies on the pressure of elastic elements (such as springs or bellows) and the sealing medium to generate a proper pressing force with the contact ends of the moving ring rotating with the shaft and the stationary ring not rotating with the shaft upward, so that the two contact end faces Closely fit, maintaining a very thin liquid film between the end faces, so as to achieve the purpose of sealing. my country's mechanical seals not only have gaps with foreign countries in performance, but also have gaps in varieties and specifications, so there is an urgent need for development. The current development trends can be divided into the following points:
1. Narrow face sealing, improve sealing performance and reduce friction and heat generation.
2. Develop towards high PV value to meet the requirements of high speed and high pressure.
3. Application of tandem double-end, multi-end and compound seals (such as common mechanical seals and
bellows seals).
4. Low temperature and extremely low temperature sealing.
5. High viscosity, sealing of medium containing particles.
6. Seals with higher safety and reliability, such as mechanical seals for nuclear power plant pumps.
7. Research on special materials, suitable paired materials and easy-to-form materials. New ceramics are a new direction of research.
8. Improve the shape of the two sealing end faces.
9. Expand the application of easy loading and unloading and split seal.
10. Expand the application of welded corrugated pipes and multi-layer (two or three layers) corrugated pipes.
11. Expand the application of sealing surface leakage detection and alarm devices.
12. Scientific and systematic research on management. It must be pointed out that the gap is not limited to sealing performance and varieties, and the gap in management is also an issue worthy of attention. Foreign sealing companies have a complete product code and material code system, which corresponds to the design drawings. Serialized and standardized production, strong versatility and flexible production, the products meet both standard specifications and user requirements.
