Oil Lubricated seals

OIL LUBRICATED SEALS

Oil-lubricated seals are used most often for sealing rotary shaft applications. Oil-lubricated systems are the most common, but ship owners occasionally use water-lubricated and grease-lubricated systems.

ABOUT OUR SEALS

We believe a seal should deliver top performance, keep you going and offer you Peace of Mind. This idea led to the development of the oil lubricated Supreme® seal. Introduced in the 1980s and further developed ever since, Supreme oil seals offer a ‘plus’ to many propulsion systems and vessels worldwide.

Our oil-lubricated Supreme shaft seals are used in stern tubes, thrusters, bulkheads, fin stabilisers, rudder stocks and gearboxes. The Supreme oil seals are produced with high quality housing parts, rubber lip seals and liners.

HOW OIL-LUBRICATED SEALS WORK

The oil-lubricated Supreme seals closes the gap between stationary and moving components of rotating shafts. It prevents the escape of lubricants (oil leakage) and ingress of harmful materials such as dirt or sand. The lube oil system circulates the oil and controls pressure, flow and temperature in order to build up an appropriate lubrication film for the white metal slide bearing.

OIL TYPES

There are two most used oil types: environmentally acceptable lubricant (EAL) and mineral oil. EAL means lubricants that are biodegradable, non-bio accumulative and minimally toxic. We’ve tested several EALs in our own laboratory in cooperation with the oil suppliers. We’ve compiled a list of compatible oils and more extensive information in our Vessel General Permit information letter.

Lagersmit recommends using oils with a minimum ISO 3448 Kinematic Viscosity Grade of 68 cSt (mm2/s) at 40 °C.

NBR OR FKM LIP SEALS

If you want to sail with an EAL, you have to check the compatibility of the EAL with the rubber compound of the seal. In most situations, an FKM compound will be used together with an EAL. However, no two EALs are the same and that is why there is no guarantee that our seals are compatible with every EAL.
EALs can chemically affect sealing rings by hydrolysis. In particular, when emulsions are built up in the oil chambers of the sealing system or in the stern tube, these bio-oils interact with the water present and tend to break down. The lifetime of most NBR or FKM lip-type sealing systems will decrease due to this aggressive mixture. When using an EAL, the use of Supreme® FKM-EAL lip seals is strongly recommended by Lagersmit.