Tiivisterenkaat

Tiivisterenkaat, commonly translated as O-ring in English, are sealing rings with a circular cross-section that fit into a groove and are compressed to form a seal between two mating surfaces. They are used in both static and dynamic applications to prevent the passage of liquids or gases. Due to their simple geometry and broad material options, tiivisterenkaat are widely used in hydraulics, pneumatics, automotive, plumbing, and consumer devices.

Materials and properties: O-rings are typically made from elastomeric polymers such as nitrile rubber (NBR), fluoroelastomer (FKM/Viton), ethylene propylene diene monomer (EPDM), silicone (VMQ), and sometimes fluorosilicone or fluorinated polymers. For higher chemical resistance or temperature requirements, PTFE-based or other advanced materials may be used. The hardness (Shore A) and tolerances on inner diameter and cross-section are selected to match the groove and operating conditions. Service temperatures depend on material, commonly from about -60°C to around +200°C, with some materials rated higher or lower.

Standards and installation: International standards such as ISO 3601 define standard O-ring sizes; other regions use AS 568 or DIN standards. Correct groove dimensions, compatible lubricants, and careful installation are essential to prevent twisting, nicking, or extrusion. In high-pressure or high-temperature service, backup rings or face seals may be employed.

See also: O-ring, gasket, seal.