The mechanical face seals are designed in such a way that they open out from the seal faces towards the centre axis, forming a cone-shaped gap which has following benefits:
due to capillary action in the gap and centrifugal force, lubricant admits easily into the seal faces, potential cold welding of the seal faces is avoided since adequate lubrication and cooling is assured, as wear goes on, sealing band increases and it can virtually only end when the seal collar gets completely worn out. This sealing system retains a continuous oil film in the sealing surfaces