Mechanical Face Seal Type 76.90H/97H
Mechanical face seal type 76.90H/76.97H consists of two geometrically identical metallic seal rings, located against the respective housing bores by means of large-volume O-rings.
At installation, the O-rings lodged between the tapered contact faces of the seal ring and housing undergo a defined deformation which is crucial for permanent operation of the sealing system (dimension “A”).
The resilience of the O-rings acts in a number of ways:
- it exerts an axial load on the metallic sealing faces
- transmits the frictional torque to the housing components
- and provides a static seal between each seal ring and its housing bore
The seal faces of the metallic rings are lapped to a radial width of about 2.5mm and are therefore finely tuned to one another from early life.
The rings are designed in such a way that they open out from the seal faces towards the centre axis, forming a wedge-shaped gap which has the following benefits:
- the lubricant is readily admitted to the seal faces by capillary action and centrifugal force
- adequate lubrication and cooling are assured and potential cold welding of the seal faces is avoided
- as wear increases, the sealing face graduates towards the centre axis; the seal therefore has large wear reserves which virtually only end when the inside diameter is reached
the traces of lubricant visible at the outer gap indicate that the seal is optimally constructed and is working perfectly