1. Initial stage (1960-1970)
During this period, the working pressure of the hydraulic system of the product is about 12-14mpa. The sealing elements used in the sealing system are: 0-shaped rubber sealing ring (NBR); iron shell and cow leather rotary oil seal; end face seal of corrugated steel skin + cork + metal spring; asbestos packing; asbestos + rubber sealing gasket; V-shaped sealing ring (cowhide + phenolic + bakelite); V-shaped sealing ring (NBR + sandwich fabric); soft joint sealing gasket, etc.
2. Entrepreneurial stage (1971-1980)
During this period, the working pressure of the hydraulic system of the product is about 14-3.5mpa. The rubber plastic seal is the main seal used in the sealing system, and the face seal of cow hide, asbestos fiber, corrugated steel skin and cork is eliminated. The main types are: 0-shaped seal ring (NBR, FKM); floating oil seal for crawler D chassis (metal ring dry 0-shaped diagram); D-type inner package framework rotary oil seal (BR, FKM, zacm). Hydraulic and pneumatic reciprocating seals include 0-ring (NBR, FKM); U-shaped dense D-ring (NBR, Au, BU); V-shaped seal ring (nbr-10-clip fabric); cup-shaped seal ring (nbr-10-clip fabric), etc. In the past 10 years, in order to adapt to engineering machinery, forging machinery, etc., medium and high pressure hydraulic technology has been adopted, and seven professional rubber and plastic seal production plants have been established by the original mechanical department. In addition, in order to promote the development of sealing technology in China, the "national hydraulic and pneumatic Standardization Technical Committee", "rubber and plastic seal standardization sub committee of national hydraulic and pneumatic Standardization Technical Committee" and "fluid sealing technical committee of friction society" were established in 1975 and 1979.
3. Consolidation and development stage (1981-1990)
在此期间产品的液压系统的工作压力达到了16-40MPa，其密封系统采用的密封件仍以橡塑密封制品为主。主要型式有：O形密封圈 (NBR、FKM)；履带底盘用浮动油封(O形图十金属环)；润滑密封履带用密封组件(NBR+AU):内骨架和外骨架旋转油生十(NBR、FKM、 ACM、EPDM)；组合密封垫圈(NBR+金属)；液压缸活塞和活塞杆动密。封用同轴密封组件(PTFE+NBR)；旋转轴用动液压回流油封(NBR、 FKM、ACM)；工作压力为13MPa的耐压型旋转油封(NBR、FKM)；双向介质旋转油封(NBR、FKM)；液O压缸活塞用带支承环双作用往复D动密封组件(NBR+PTFE+POM)等。
During this period, the working pressure of the hydraulic system of the product reached 16-40mpa, and the rubber plastic sealing products were still the main sealing parts of the sealing system. The main types are: O-ring seal (NBR, FKM); floating oil seal for crawler chassis (O-shape diagram x metal ring); sealing component for lubricating sealing track (NBR + AU): rotating oil generator for inner and outer framework (NBR, FKM, ACM, EPDM); combined sealing washer (NBR + metal); dynamic tightness of hydraulic cylinder piston and piston rod. Seal with coaxial seal assembly (PTFE + NBR), rotating shaft with dynamic hydraulic return oil seal (NBR, FKM, ACM); pressure resistant rotary oil seal (NBR, FKM) with working pressure of 13Mpa; bidirectional medium rotary oil seal (NBR, FKM); double acting reciprocating d dynamic sealing assembly with supporting ring for hydraulic o cylinder piston (NBR + PTFE + POM), etc.
4. High speed development stage (after 1991)
Construction machinery and other medium and high-pressure hydraulic industries have introduced a large number of product manufacturing technology, which has promoted foreign seal merchants to enter the seal Market in China. The entry of foreign capital and technology has improved the overall level of China's mechanical seal industry.