The generation of contact pressure is crucial during the contact process between a rubber seal and its mating surfaces. Contact pressure refers to the pressure generated on the mating surfaces due to the elastic deformation of the rubber seal. This pressure can fill the tiny gaps between the mating surfaces, preventing media (such as gases or liquids) from leaking through these gaps. The stronger the elastic deformation capacity of the rubber, the greater the contact pressure generated, and the better the sealing effect. Simultaneously, the plasticity of rubber materials also plays an important role. Plasticity allows rubber seals to undergo plastic deformation under pressure, further filling defects and unevenness at the mating surfaces, enhancing the sealing effect.
Besides elastic deformation and plasticity, the working principle of rubber seals also involves the generation of sealing force. Sealing force is the rebound force generated when the rubber seal is compressed; it acts on the mating surfaces to prevent media leakage. The magnitude of the sealing force depends on the elastic modulus of the rubber material, the geometry of the seal, and the pressure applied to the seal. When the sealing force is greater than the internal pressure of the sealed medium, the medium cannot leak through the mating surfaces, thus achieving an effective seal.
Self-sealing is another important characteristic of rubber seals. After installation, the rubber seal will have an initial sealing stress on the mating surfaces. When the equipment starts running, the internal liquid pressure is transmitted to the sealing surface, causing an increase in sealing stress. Even if the internal liquid pressure increases and exceeds the initial sealing stress, the sealing ring can still maintain a sealed state due to the incompressibility and elastic deformation capacity of the rubber; this is the self-sealing effect.
