Mechanical face seals or heavy duty seals are specifically designed for rotary applications in extremely arduous environments where they resist severe wear and prevent the entry of abrasive and hard external media

The DO type is the most common way that uses an O-ring as a secondary sealing element

The DF type has an elastomer with a diamond-shaped cross section as a secondary sealing element
instead of the o-ring

Both types consist of two identical metal seal rings mounted in two separate housings of wrapped seal faces. The metal ring is located in the center of the housing by the elastomeric element. Half of the mechanical face seal is fixed to the housing and the other half rotates to the opposite side.

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