They are typically made from elastomers such as rubber or silicone and consist of an outer metal case with a sealing lip on the inner side.
In this kind of seal, wider tolerances are possible between the OD of the seal and the seal housing. Irregularities of the housing surface can be taken up by the resilient rubber layer on the outside of the seal. However, the rubber covered seal can be blown out under high pressure in a reciprocating application whereas, with a metal case, there is no such danger.
Shaft Surface Finishing
Various materials with unique properties are utilised in the construction of rotary shaft seals, allowing manufacturers to tailor the sealing solution to specific industry requirements and ensure optimal performance.