What are the basic requirements for rubber seal design?

Different equipment has different performance requirements for rubber seals. The design and type of rubber seals should be carefully analyzed and compared based on the specific application. The key performance requirements for seals are as follows:

1. Allowable leakage. Leakage is a key requirement in rubber seal design, which is determined by the seal's intended use. The allowable leakage rate is the leakage rate permitted to ensure proper operation of the equipment. This rate is generally determined based on the specific equipment and there is no universal standard.

2. Friction. Friction causes heat and wear on the rubber seal, even damaging the sealing surface of the component. It is the main cause of seal failure and leakage. The friction of contact seals is primarily determined by the material's coefficient of friction and lubrication conditions.

3. Wear. Friction causes wear, which inevitably degrades the performance of the rubber seal and shortens the service life of the equipment. The amount of wear on the seal and rotating shaft surface depends on the seal type, the rubber seal material, and the lubricity of the fluid. Packing seals exert greater wear on the shaft, especially when the medium contains abrasives.

4. Dimensions. Sealing devices should be as compact as possible, and the structural dimensions should be determined by the overall machine.

The selection of rubber sealing rings should be based on a comprehensive consideration of the operating system's temperature and pressure, the type of sealed media, its corrosiveness, toxicity, flammability, explosiveness, contamination, density, viscosity, and the shape of the sealing surface. Generally speaking, at room temperature and low pressure, non-metallic soft rubber sealing rings are used; when there are large temperature and pressure fluctuations, highly elastic sealing rings or self-tightening sealing rings are used; when working with low temperatures, corrosive media, or vacuum conditions, sealing rings with special properties should be considered.