The performance of non-asbestos board sealing material is an important factor to ensure effective sealing. The choice of sealing material is mainly based on the working environment of the sealing element, such as temperature, working pressure, working medium used and movement mode. The basic requirements of sealing materials are as follows:
1. Have certain mechanical properties, such as tensile strength, elongation, etc.;
2. Appropriate elasticity and hardness, compression deformation;
3. High temperature and low temperature resistance, no decomposition and softening at high temperature, and no hardening at low temperature;
4. Compatible with working medium, no swelling, decomposition, hardening, etc.;
5. Good oxygen resistance and aging resistance, durable;
6. Wear-resistant, non-corrosive to metal;
7. Easy to shape and process, low price;
With the increasingly stringent use conditions of mechanical products, higher requirements have been placed on the use conditions of non-asbestos rubber sheet sealing products, such as in aerospace, aviation, petroleum and mining, construction machinery and transportation, and energy industries. It is often necessary to adapt to harsh environments such as wide temperature environment, high pressure, sand and dust. According to the data of the International Rubber Conference in 1984, the conditions for using rotary shaft lip seals on automobiles and tractors have been greatly developed.
Due to changes in use conditions, the consumption of special rubber will continue to increase, and new seals need to be developed to improve the service life and reliability of the seals. The working pressure of the rotary shaft lip seal ring is usually 0.1~3.5MPa, and the high speed is 15~20m/s. The higher speed of the fluid power type can reach 25~32m/s. But in higher cases, the working pressure will be slightly lower.
There are many types of reciprocating seals, the common ones are J type, L type, U type, V type and Y type. There are also various combinations and composite seals. Such as Peng shape, bud shape, multi-lip shape and so on.
The system pressure of the reciprocating seal is usually lower than 20MPa. The high-performance composite seals used in the aerospace industry can reach a system pressure of 56MPa. At this time, the higher working speed is 1m/s. With the development of my country's economic construction, the requirements for the development of seals for use in mountains, deserts and underwater environments have been put forward. Extrusion type seals, especially O-rings, have been widely used in seals. X type, T type, D type, square, triangle and other types are also suitable for different occasions.
The improvement direction is to make its sealing performance stable and reliable, improve its pressure resistance and reduce friction. It can also form a combined seal with low-friction plastics (such as PTFE, nylon slip rings and support rings). Improve its pressure resistance and reduce friction. Some manufacturers' products allow a speed of 7.5m/s and a sealing pressure of 5.6MPa.
Reciprocating lip seals, also known as lip liners or leather cups, are widely used in dynamic sealing of reciprocating cylinders in hydraulic systems. The pressure-bearing surface of this seal is lip-shaped and has little interference during the installation process, so the lip and the sealing surface are in complete contact to produce a sealing effect. When the oil cylinder works, as the pressure increases, its contact force and contact area increase, thereby improving the sealing performance. In the return stroke of the cylinder, the pressure rises, and the contact area and friction are less than the working stroke, so the breathing effect is produced and the lips are lubricated.
The above is all the content introduced by the non-asbestos board manufacturers. To learn more about sealing materials, please follow the company's official website!