

Polyacrylate
Type ‘C’ oil seal has an additional cup inserted into the outer cup of ‘B’ type. The supplementary metal inner ring provides a superior stiffness. This type is recommended for use in heavy polluted environments. As the static sealing between housing and metallic shell is limited, low viscosity media can “creep”.
The shaft on which the oil seal is mounted has to be ground to a rough surface finish. The shaft also should be hardened to prevent grooves forming on the shaft when the pressure is exerted by the spring on the seal. The area where the seal is fitted also has to be ground to prevent grooves that tend to wear out the lip of the oil seal faster than normal.
2. Oil seal structure and functions
Oil seal is an essential component in various machinery and equipment, designed to prevent the leakage of oil and other fluids. One of the most commonly used oil seals is the 30-50-10 oil seal, which is known for its durability and efficiency in sealing oil leaks.


Another critical factor to consider is the type of seal most suitable for particular machinery. When selecting your mechanical sealing solution, assess your machine’s shaft speed, temperature, pressure, environment, and the medium coming into contact with the seal during an operation. These factors help determine the color, size, sealing element, lip material to choose from, and if it can be sealed out or sealed in.
Operating temperatures for engine oil seals (see Fig. 14.11 and cross-section of lip seal with garter spring in Fig. 14.22) vary widely, depending on engine design and location within the engine. Typically, the rear crankshaft seal is subjected to much higher temperatures than the front seal. Oil sump temperatures vary considerably, depending on provisions for oil cooling. This allows use of hydrogenated nitrile (HNBR), silicone, or acrylic elastomers for some seals in relatively low-temperature environments (120–140°C or 250–284°F). Standard fluoroelastomers (FKM), bisphenol-cured VDF/HFP/TFE terpolymers with 68–69% fluorine content, perform well in oil service up to about 160°C (320°F). More resistant fluoroelastomers are necessary for reliable long-term performance in more severe environments.