When to Use an Oil Filter vs. a Strainer
What is the difference between an oil filter and a strainer?
Do they have different applications? When should each be utilized?"
Generally, an oil filter and a strainer seek to perform a
very similar task — to remove contaminants as oil passes through — but at a
completely different scale.
Strainers are employed to capture much larger contaminants.
By larger, this refers to objects of approximately 40 microns or greater. A
60-mesh strainer captures contaminants at around a 240-micron level, while a
100-mesh strainer captures at a 150-micron level. The mesh-to-micron particle
size correlation is determined by the number of open square-shaped gaps across
one linear inch.
Forty microns also happens to be the lower limitation of
what is visible to the unaided eye. In reality, if particles can easily be
seen, they should be trapped by a strainer. The typical application of a
strainer allows it to be cleaned relatively easily and reused.
Filters usually are much more complex in regard to the
pathways through which oil must pass. This provides more opportunities for
contaminants to be captured more efficiently, as well as for other types of
contaminants such as moisture to be trapped.
One major operating parameter that is distinctly different
in each application is flow restriction. Strainers are much less flow
restrictive than most filters, especially compared to depth-type filters. This
raises the question of the best application for a strainer versus a filter. In
most cases, strainers are seen in suction lines into a pump. If suction
pressure (toward a vacuum) is increased due to flow restriction, it can result
in pump damage via cavitation.
Unclogged strainers can be quite effective in this
application. However, as soon as the strainer surface area becomes compromised
with high levels of larger contaminants (resulting in higher flow restriction),
pump problems may occur.
With their higher capture ability, filters are much better
applied where positive pressure exists and where constant flow exists (not
pulsating). This means the best application would be on a return line or
offline kidney-loop filter location.
In application, the choice of a filter must be balanced with
the system’s operating and environmental requirements. If the requirements call
for a filter at a lower micron level (and/or better beta ratio), then the size
of the filter (fluid flow cross-sectional area) must be increased or a higher
differential pressure will result.
Cr. By
www.machinerylubrication.com
ABKOTEC LIMITED PARTNERSHIP
12 Soi Bangna-Trad25, Bangna, Bangna, Bangkok Thailand 10260
Tel. 02-7440761
Fax. 02-7443230
ฝ่ายขาย 24 ชม. M. 086-3679336, 095-9627339, 061-5906036
www.abkotec.com , www.strainer-filter.com
