Select Page

Des-Case Blog

A Guide to Oil Filtration

Jun 2, 2020

Everyone is interested in extending life…and a company’s equipment is no exception. While our equipment won’t last forever, more and more companies are looking for processes and products that will help keep them up and running. Reduced downtime, increased lubricant life, less recycling and repair cost are becoming more important than ever as the industry moves to the next level.

Maintaining clean oil is one of the best investments a company can make, yet contamination often remains an overlooked factor behind premature machinery failure and diminished lubricant life. With the cost of oil, increased desire to minimize usage and waste, and the need to prolong the life of equipment, the economic case for protection—from the time oil enters a facility until it leaves—is stronger than ever.

Contamination: The Problem

Two primary types of contamination include dirt and water.

If the atmosphere is contaminated (and most are to some degree), the oil is probably dirty and lubricant quality is compromised. Particulate contamination, once inside an operating system, will
accelerate the generation of new contaminants. These contaminants damage critical components and act as a catalyst for oxidation, further degrading lube condition.

If the atmosphere is particularly humid or has frequent temperature fluctuations, the oil is probably moisture-laden and lubricant quality is compromised. Oftentimes, plant wash down activities are responsible for inducing conditions that lead to moisture ingression and corrosion.

The good news is that these factors, which work together to threaten equipment reliability, can be effectively controlled with some preventative maintenance techniques. The best and easiest way to exclude contaminants is to avoid practices that risk exposing lubes to contaminants.

Achieving Clean Oil

Before a lubrication best practices program can be created it is important to consider the industry you’re in and your applications.

Every industry and application is unique – and what’s right for someone in one environment isn’t what’s needed for someone else with finer tolerances, a more critical application or a different type of equipment.

It has been said that the best cure is prevention. Ideally, all of us would have a brand new plant and machinery and begin with a solid program of preventative measures that would ensure the longest life for our equipment and oil. That, of course, never happens.

Once you know how big the problem is, you can combine several options to help bring the current situation in line with your cleanliness targets, and add components that will help keep your oil clean and dry.

What is Oil Filtration?

Reservoir Filters

Today’s options for restricting the ingression of contaminants are a far cry from yesterday’s open tube turndown pipes that did little more than keep the birds out. Proper installation and maintenance of desiccant breathers can significantly reduce ingression of airborne contaminants.

Conventional vent ports or breather caps provide little or no protection. They are typically rated at 40 micron and offer no means of capturing moisture. Retrofitting these ports with breathers will provide nonstop protection against uninvited contaminants, both dirt and water. Clean lubricants extend the life of equipment, and lower the total cost of ownership with lower oil, repair, downtime and maintenance costs.

Benefits of a Desiccant Breather

Breathers are essential to the health of machines and lubricants. A properly fitted and maintained breather is a critical step
toward reliability optimization. Combining breather use with other contamination control tools, such as mechanical seals,
proper sampling techniques, downstream filters and appropriate lubricant storage/dispensing systems will increase the overall level of maintainability and increase the chances of meeting or even exceeding life expectancy.

Basic Forms of Oil Filtration

There are two basic forms of oil filtration: in-line or off-line. Any circulating system should have in-line filters on the pressurized
supply line so that the oil that is fed to the moving components is clean and dry. However, oftentimes in-line filters cannot
adequately control contaminants at low enough levels without significant and costly upgrades.

Under these circumstances off-line filtration is an excellent, cost effective solution. Off-line filtration, sometimes called by-pass or kidney loop filtration oil is extracted from the main system by an external pump, which makes it possible to filter the oil even when the main system in not in operation. Changing filter elements is made easy and can also be done without interrupting the main system.

Types Of Oil Filtration Systems

Off-line filtration can be either permanently installed on the system or portable.

Portable Filtration

While permanent off-line filtration will usually offer better overall contamination control, portable filtration, which can be connected and disconnected to the machine by way of quick connects, offers the advantage that the same filtration system can be used for multiple machines; provided each machine uses the same oil type.

Portable units aren’t just for offline filtration anymore. Many maintenance professionals have discovered that portable applications can be used for dispensing new oil, performing oil changes, cleaning parts, and flushing new components to name a few.

Ideally, portable filtration should be used as a “condition-based” activity, providing a means to decontaminate systems when the particle count exceeds an acceptable limit. Having this option offers the ability to decontaminate any system in a plant when many of those systems can’t justify their own dedicated filtration system.

Dedicated Filtration

The potential problem with portable filtration comes with the required resources for moving and setting up the system. If the portable unit was used with another lubricant previously, there are also flushing requirements and possibly filter changes as well. While portable systems will always have their place, permanent solutions offer several benefits including better average fluid cleanliness and far fewer man-hours.

When portable filtration is used periodically, maintaining target cleanliness levels can become a challenge. It may be that fluid cleanliness targets are only met for a short period after filtration and then remain unacceptably high until the next scheduled filtration task. Permanent filtration provides continuous protection of the lubricant.

Choosing the Right Oil Filtration Option

A little planning goes a long way in selecting the right fluid handling solution. Careful evaluation of your situation—including existing and desired cleanliness levels for filter selection, fluid viscosity for pump selection, location for frame selection, and specific application for other options—will help you determine which filtration solution can best meet your needs most efficiently and cost effectively.