Coalescing Air Filters For Oil Removal from Air

Although general-purpose filters may work for many, there are better answers for some applications or the proper treatment of condensate. Sometimes, applications require more oil to be removed from their airstream or need help with additional moisture. 

These filters are constructed to attract moisture and oil from the air. The fibers’ nature causes the water and oil to fuse or merge with the other particles present. The air can continue passing through by trapping them in the fibers while the water and oil stay behind. After enough of the specific material is present, the moisture will drop to the bottom of the filter.

Coalescing filters traditionally come after a general-purpose particulate filter but before the dryer. This allows the bigger particles to be removed before the air makes it to the coalescing filter, which these larger particles would easily clog. This combination provides the best possible removal of condensate and particulates before the dryer so that the dryer can work as expected without being overwhelmed.

Coalescing Compressed Air Filtration

So, how exactly do these filters work to remove condensation from your compressed air? We know they have fibers that attract water and oil, making them hydrophilic. By relying on hydrophilic properties to pull the water and oil from the air, the water and oil do not need to be forced out of the airstream or have the flow nearly impeded to remove the condensate.

Condensate in your system can cause pressure drops, rusted components, unplanned downtime, and even completely derail your system. Over a few people have had their pipes explode from internal wear and material degradation, finally giving way to air pressure. 

Proper filtration can be the difference between saving yourself a little extra money or buying a whole new system due to moisture and particulate damage.

Ensure Your Filter is Sized Properly

The size of your compressed air filter is determined by the size and type of particles being removed. You want to be able to remove the particles in descending size so that you do not clog the filter elements. The bigger particles will get caught as the air passes through, and smaller and smaller particles will make it through.

Consider a few things when you are looking to buy an air filter. These will be the guiding principles for selecting your compressed air filters.

Extraction Efficiency

This is the percentage of dust removed or extracted from the air. So, a filter sized to 1 micron would have a 99.8% extraction efficiency because .2% of the particles that size pass through the filter.

Flow Rate

Flow rate is the air that passes through the filter in a given period, usually measured in Cubic Feet per Minute (CFM). Your filter size has to match your flow rate, so if you have a more significant flow, you will need larger compressed air filters. If your flow rate is too much or too low for your filter, it can cause unwanted pressure spikes and drops.

Flow Resistance/ Dust Capacity

Flow resistance refers to the buildup of dust and debris in your filter over time. As this builds up, more dust will accumulate, causing pressure drops and restricting the flow of your compressed air. Stay on top of this by routinely replacing your filter elements and preventing extreme buildup.

These are the main concerns you should have when determining your filtration sizing. Beyond that, there really isn’t much else to keep in mind aside from pressure drops, and all that takes is a simple calculation.

Want to learn more about compressed air filters? Check out our guide on compressed air filters here.