|
Transitioning to a New Lube Supplier
Khalid Malik, Technical Officer, Ontario Power
Generation
One must always be careful in doing this practice and it is a
real challenge to mix different oils because it is possible in
most cases that the two will be incompatible, particularly the
additives in each oil.
Of course, changing lube brand is sometime inevitable and we
cannot be expected to drain every drop of old oil from the equipment
and replace it with the new oil!
The first step I would recommend is to consult with the new supplier
any incompatibilities that are known between corresponding products
from each vendor that will be used in the same application. Usually,
they will provide a cross-reference guide of equivalent products
that are compatible and have the same minimum performance specifications.
If any doubt exists, compatibility testing should be conducted
as follows:
Take three different mixes of oil A and oil B, one at 50:50,
one at 90:10 and the third at 10:90 and test for filterability,
sediment (possibly caused by additive drop-out), color and clarity,
RPVOT, storage stability, demulsibility, rust and corrosion inhibition,
air release and foaming tendency. Also seals compatibility will
be considered as some base oils are not friendly with elastomers.
In Nuclear business, we always recommend for radiation resistance
and thermal aging test. Provided all mixtures pass these performance
tests, there is a good possibility that the two oils are compatible.
The grease compatibility should also be taken very seriously
because in greases, the biggest problem is compatibility of soap
thickeners. Incompatible greases can either thicken or thin when
mixed and therefore extreme care must be taken when switching
from one product to another. In general, without any mixing or
compatibility data , all greases should be treated as incompatible.
It is strongly recommended that equipment /bearing/ housing should
be thoroughly cleaned and purged before introducing the new grease.
See other responses
to this Readers Challenge.
|
