Shaft seals (Oil Seals)
Shaft seal, also known as a oil seal, rotary seal or simmering seal, is a sealing element used in mechanical devices to prevent the leakage of liquid or gas between two surfaces. Its main purpose is to keep lubricant in and contaminants out, extending the life of bearings and other moving parts. Bearings are often made of materials that are resistant to wear and chemicals. Gaskets can come in a variety of shapes and sizes and are used in automotive, machinery, agricultural machinery and many other industries. Seals are crucial to the proper functioning of engines, transmissions and hydraulic systems. Proper selection and installation of a bearing ensures smooth operation of equipment and minimizes the risk of failures. Investing in quality bearings therefore pays off in terms of maintenance and operational reliability.
Sealing types:
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G/WA - single-edged radial rotary shaft seal ring without dust cover
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GP/WAS - double-edged radial rotary shaft seal ring with dust cap
Shaft seal materials:
NBR - Nitrile Butadiene Rubber (NBR), offers high tensile strength and low swelling in water. The temperature usage range is from -40 °C to 100 °C depending on the type of fluid used. Specific temperature limits for constant temperature loads are 70 °C for HSB emulsions (water-oil) and HSC aqueous solutions, 80 °C for gear and hypoid oils, 90 °C for pressure fluids, heating oils and greases and a maximum temperature of 100 °C for engine and ATF oils. NBR material has limited resistance to ozone, organic solvents and aromatic liquids.
VITON/FPM/FKM - fluoro rubber rubber material with high elasticity, which is the only one resistant to chlorinated and aromatic hydrochlorides.It has excellent resistance to weathering, ozone and acids. Its advantages also include low swelling in hot water and steam. The temperature range of use of the lubricant is from -30°C, while from -20°C the resistance and elasticity of the lubricant is already low. The upper temperature limit is up to 170 °C, depending on the type of fluid used. Specific temperature limits for constant temperature loads are 100°C for water and washing liquids, 150°C for gear oils, ATF oils, pressure fluids, heating oils and anhydrous solutions and a maximum temperature of 170°C for engine and hypoid oils. This material has limited wear resistance, low solvent resistance, limited tensile and tear strength, especially at temperatures above 100°.
SI MQV – Silicone Rubber (VMQ) is a heat-resistant elastomer with excellent flexibility across a wide temperature range. It resists UV radiation, ozone, weathering, and oxidation, making it an ideal material for both outdoor and stationary applications. It is chemically stable against water, alcohols, glycol-based brake fluids, and both vegetable and animal oils. The operating temperature range is from -60 °C to +200 °C, with short-term resistance up to +230 °C, while maintaining flexibility even at extremely low temperatures. Suitable for static sealing, especially in the food industry, healthcare, and electronics. It is commonly used where high purity, thermal stability, and aging resistance are required.
Disadvantages: Low resistance to fuels, mineral oils, abrasive wear, and mechanical stress. Not suitable for dynamic applications involving high pressure or strong friction.
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