Oil Filters vs. Oil Strainers
A common misconception is that oil filters and spacer oil strainers are the same thing. While this is not totally true, they do bear many similarities to one another. Their first similarity is the task they perform: to remove contaminants from oil as it passes through. Additionally, both filters and strainers protect downstream equipment by removing debris or contaminants that would otherwise compromise the integrity of the component. Both filters and strainers can be required by law or regulation for a variety of safety or environmental reasons, to improve the efficiency of the system, or merely for practical purposes. In many cases, the flowstream would be rendered useless without a filter or strainer.
The main difference between filters and strainers is found in the size of the particles they are removing. A filter is used to remove particles smaller than 40 microns, while strainers are employed to remove particles of bolt sustainer larger than 40 microns. A micron is a unit of length, equivalent to one one-thousandth of a millimeter. More simply put, a strainer is used when the particles are visible to the naked eye, while a filter is used when the particulate cannot be seen.
Because they are tasked with removing much smaller material, filters are generally much more complex in regard to the pathways through which oil must pass. This allows them to more efficiently capture contaminants and provides them with the capability of trapping other types of contaminants such as moisture. Another major difference between filters and strainers is how they restrict flow. Strainers are much less flow-restrictive than filters, especially when compared to depth-type adapter filters. A depth-type filter is a type of filter that employs a porous filtration medium to retain particles throughout the filter, rather than just on the surface of the medium as normal filters and strainers do.
These differences raise the question of the best application for a strainer versus a filter. In many cases, strainers are found in the suction lines entering a pump. If the suction pressure toward a vacuum is increased due to flow restriction, it can result in pump damage caused by cavitation. Cavitation is a phenomenon wherein rapid changes of pressure in a liquid lead to the formation of small vapor-filled cavities in places where the pressure is comparatively low. Strainers are highly-effective in this application as long as they remain unclogged. As soon as the strainer surface becomes riddled with high levels of foreign contaminants, flow is restricted and can cause serious pump problems.
Thanks to their higher contaminant removal capability, filters are more beneficial in areas where positive pressure and constant, non-pulsating flow exist. Filter’s best applications are in return lines or kidney loop filtration systems. Whatever the application, filter choice must adhere to the operational and environmental requirements of the system where it is applied. For example, if a system requires a filter of a lower micron level, the size of the filter should be increased. If too small a filter is used, a higher differential pressure will result.
While filters and strainers are very similar, it’s important to know their unique characteristics before deciding which one you need. At ASAP Aviation Stock, owned and operated by ASAP Semiconductor, we can help you find all types of oil filters and air strainers for the aerospace, civil aviation, and defense industries. Our inventory of over six billion parts also features strainer oil, fastener filter, base oil filter, and more. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@asapaviationstock.com or call us at 1-763-401-8616. Our team of dedicated account managers is standing by and will respond to you in 15 minutes or less.
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