1. The conventional standard type oil seal is still used in a large number of rotating seal systems. For the pressure required rotating seals, the pressure resistant oil seal can only be supplied with pressure of 1-3MPa, but the international advanced level is 10MPa.
2. Most domestic construction machinery hydraulic cylinder dynamic seal system design is still using U shape seal ring as the main seal. In the middle of 90s, the dynamic seal system of hydraulic cylinder for construction machinery was designed and manufactured. The coaxial seal assembly and the U seal ring were used in the design. The 5 components (or 3 components) of the hydraulic cylinder are commonly used in the world. The combined seal assembly with bearing ring is more complicated. At present, the quality stability is poor on the stage of small batch production at home.
3. Although the static sealing system has cancelled the sealing products of asbestos and plant fiber, the use of liquid sealing gaskets for polymer materials is still in use. It is not universal. The products of domestic liquid sealant and anaerobic adhesive used for connection of the hydraulic system are few, and there is a certain gap between the coating process and the quality performance.
China's seals and seals manufacturing industry will face serious problems posed by construction machinery and other medium and high pressure hydraulic machinery industries. With the introduction of international advanced technology and manufacturing technology.
After 2000, the development trend of the national economy and the development of China's construction machinery industry based on advanced technology will be greatly developed. The working pressure of the mechanical hydraulic system and the advanced and reliable work of the system will certainly promote the design of the seal system and the development of the manufacturing technology of the sealing element. Therefore, the scientific research and seal manufacturing industry in China will face the severe issues raised by the engineering machinery and other medium and high pressure hydraulic machinery industry. It is expected that the Chinese sealed industrial system will no longer be a small farm economy model with high energy consumption, low efficiency and complex structure, and will be a highly intensive, large-scale, low energy consumption, high efficiency management system. Therefore, all kinds of sealing ways are improved, including double cartridge mechanical seal
,rubber seal, carbon seal and so on.