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Is it possible to overfilter oil?

One of the most common concerns we are asked to address is the issue of whether or not it is ever possible to overfilter lubricant. This is a question that it is much more difficult to answer than you would probably think.

It is true to say that the cleaner an oil is, the less likely bearing or machine wear becomes. However, this is not the whole story, and there are several points that need to be considered when aiming for extremely low ISO cleanliness codes.

Machine tolerances

One issue that warrants some consideration is the tolerance of any machinery you are using and its requirements for clean oil. For example, hydraulic systems have a reputation for requiring clean oil, whereas something like an industrial gearbox may not need oil to be quite so clean in order to function well. This depends on a range of circumstances, including its age and criticality.

The right filter

Once you have worked out how clean a machine needs to be to function at optimum levels, you will need to choose a filter that will enable the machine to meet these levels. The benchmark of filter performance is usually its micron rating, but the micron rating alone cannot tell you everything you need to know – the beta ratio must also be considered.

A filter’s micron rating will tell you how fine the item being usde is, whereas the beta ratio will tell you how efficient it is at catching particles at that particular micron value. With these figures, you will be able to work out which filter will work most efficiently for you.

Submicron filters

It is possible to purchase filters that can operate at a submicron level. This may sound like a good thing, but filters that are able to work this aggressively will often start to strip out additives, and this can have a negative effect on the health of your lubricant and its ability to protect the surfaces of your equipment to an adequate level.

So, although it is always better to have clean oil. It is important that you also take into account the needs of your machinery equipment when buying a filter. You should tailor your choices to the machine being used, and take the time to choose the most appropriate product to get the job done.

If you are unsure as to what kind of filter would be the best for you and your equipment, it would be wise to consult an expert, as it could save you a lot of money long-term.