Oil seals are for rotating shafts and are specifically designed to prevent oil or grease leakage at a maximum pressure of 10 psi. The seal consist of one or more rubber sealing lips, a stiffening metal core and usually a garter spring. There are three standard types:
Type A has a rubber elastomer outer covering that tolerates thermal expansion as well as roughness in the housing bore. Type B has a metallic casing that enables easier fitting. However, this type demands closer tolerances in the housing bore to ensure the sealing process. Type C has a metallic casing with reinforcing cap. This type is applied in case of rougher operating conditions and where larger dimensions are utilized.
The coating and sealing lips are rubber, usually nitrile, but can be made in other compounds, most commonly FKM. Temperature range for Nitrile is minus 40-degrees to +240-degrees, with a maximum pressure range of 10 psi and speed of 3 feet per second.
There are a multitude of lip designs in single lip, double lip and in some cases even triple lip. The lip contacts the shaft, and depending on the pressure and angle of the lip, determines how wet the seal runs. Rocket Seals carries a wide variety of sizes and styles in both standard and metric sizes. We are an authorized SKF dealer (formerly known as Chicago Rawhide) CR seals and Speedi Sleeves.