The two main different types of face seals are O-ring type (DO type) and trapezoid type (DF type). These types refer to the shape of the secondary sealing element cross-section. DO type is the most common. DF type offers easier installation without special tools, as well as more easily machined housings.Both types consist of two identical metal seal rings mounted in two separate housings face-to-face on a lapped seal face. The metal rings are centered within their housings by an elastomer element. One half of the Mechanical Face Seal remains static in the housing, while the other half rotates with its counter face.

DF Type Mechanical Face Seal Introduction

DF type mechanical face seal also called heavy duty seal,it has an elastomer with a diamond-shaped cross section as a secondary sealing element instead of the O Ring. The seal rings are assembled with trapezoid elastomer parts which are positionedagainst the particular housing bore.DF type requires slightly less installation space in theaxial direction than the standard DO type mechanical face seal. The geometry of the housing contour is easier to manufacture, and the seal installation does not require an installation tool.