Why do your new oil filters fail you?
Your filters are the gatekeeper for the health of your oil. Nothing can deflate a machine operator quite as malfunctioning filter elements. It may be the most used-and-disposed consumable item for those managing oil, but it is often the root cause of most headache for operators and tribologists alike. Below, I outline the four broad types of filter failures, why they occur and the impact. In the following post/Video Blog, I shall elaborate more on what can be done to avoid these failures.
- Filter Plugging
Filters get “clogged” or “plugged” when oil flows through the circulating system without much change in routine, allowing for varnish, sludge and other contaminants to saturate the filter element. It’s like a drain in a sink getting clogged overtime when it’s not cleaned for days together. Oil analysis may show no trend indicating this type of failure, but the system will register an increased pressure differential across the filter, as the flow path is all but stopped. A simple check on the Beta Ratio of the Filter will tell you how many particles above a certain micron level are being filtered out, and if that percentage has decreased. If it has decreased, the filter efficacy is compromised. Routine changes of the filter and in the oil system will help to prevent this type of failure.
- Pore Erosion
This occurs when the filter screen becomes abrasive, worn out at frayed due to metallic particulate matter from the main and return lines through which the oil flows, fly-by particulate matter from sand, wear metal or other debris of the equipment through which oil flows at a high speed. These particles lodge in the filter material over time, blocking the pores, and a pile-on effect created by more such particles results in these pores becoming larger in size. Regular checks of the gaskets and seals can help prevent this. Once again, a Beta Ratio Test can ascertain if there has been an increasing trend in higher-micron particles that are not being captured by your filter. Alternatively, a particle counter can give you a quicker (but less accurate) estimate too.
- Filter Warping
Like a door that warps outwards upon repeated usage causing the laminate to come off, fatigue cracking occurs when the filter warps due to operational stresses, typically cyclical phases of pressure, flow and temperature.
One solution could be to have filters enclosed in an outer casing, so oil that flows through the filters over a longer period of time, and much slower minimizes the tension caused by pressure differentials. Another solution could be to choose filters made of cellulose rather than paper. Having offline kidney loop oil filtration systems like Triple R which operates on a sump-to-sump basis to avoid exposing the filters to vagaries of pressure and flow.
- Media Migration
Media Migration is often the culmination of Plugging, Pore Erosion and Warping in that the end result is a partial or complete rupture of the filter structure. In addition to normal contaminants not being caught in the filter, the problem is compounded by the new contaminants introduced in the form of the ruptured filter pieces. Plus, anything previously captured by the filter is now likely to be released into the oil flow again because of the ruptured filter element. It is as good as having no filter!
Rupture problems amplify in the presence of abrasive particles such as sand or wear metal for the equipment or the main/return lines. A pressure gauge that comes along with Kidney Loop Bypass Oil Filtration Systems( Triple R is well suited for this) can indicate level of particle count Failure can be identified by the oil system showing low or no pressure drop across the filter and oil analysis revealing an increase in the total particle count.