Filtered Compressed Air is the Best Compressed Air: Three Filter Types

When you are using compressed air to Clean, Cool, and or Dry products in production the quality of compressed air you are using is very important. You wouldn’t want to be blowing oil or condensation from your compressed air onto a surface you are trying to dry. Or blowing debris on a surface you are trying to clean.

The most common type of oil removal filter uses a coalescing element.  Oil entrained in pressurized gas flow isn’t as dense as water – so centrifugal elements won’t remove it – and it tends to act like particulate…but very fine particulate – so typical sintered particulate elements won’t remove it.  Coalescing elements, however, are made of a tight fiber mesh.  This not only catches any trace of oil in the air flow, but also much finer particulate than those sintered elements.  EXAIR Oil Removal Filters, like the Model 9027 , provide additional particulate filtration to 0.03 microns.  That’s some pretty clean air.

Dry Particulate Filters: Dry particulate filters are usually employed to remove desiccant particles after an adsorption dryer. They can also be implemented at point of use to remove any corrosion particles from the compressed air. Dry particulate filters operate in a similar manner as a coalescing filter, capturing and retaining particles within the filter media.

The particulate element captures solids larger than 5 microns, and the centrifugal element eliminates moisture.

Coalescing Filters: Coalescing filters are used for removing water and aerosols. Small droplets are caught in a filter media and merged into larger droplets that are then taken out of the filter. A re-entrainment barrier prevents these droplets from reentering the air. Most of the liquid coalescing filters remove is water and oil. These filters also remove particulates from compressed air, trapping them within the filter media, which can lead to pressure drops if not changed regularly. Coalescing filters remove most contaminants very well.

The coalescing element catches oil and very fine particulate

Adsorption Filters: Vapor removal filters are typically used to remove gaseous lubricants that will go through the coalescing filter. Because they use an adsorption process, vapor removal filters should not be used to capture lubricant aerosols. Aerosols will quickly saturate the filter, rendering it useless in a matter of hours. Sending air through a coalescing filter prior to the vapor removal filter will prevent this damage. The adsorption process uses activated carbon granules, carbon cloth or paper to capture and remove contaminants. Activated charcoal is the most common filter media because it has a large open pore structure; a handful of activated charcoal has the surface area of a football field.

Knowing the needs of your compressed air system can help you chose the right filter. If your air needs a high level of filtration or basic contaminants removed, cleaning your air is an important step in the compressed air process. Check out EXAIRS filter options here!

Jordan Shouse
Application Engineer

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Why Use Oil Removal Filters For Compressed Air

If you’re even an occasional visitor to the EXAIR Blog, you’ll know we like to write about compressed air filtration.  One reason is that many of our products have relatively small passages that can become fouled with dirt from the compressed air supply, and performance will suffer.   Even if you find yourself in that situation, though, the good news is, it’s easy to clean many of those products…worst case, some disassembly is required, but we’re here to help with that if needed.

The more pressing reason for many users is, whatever’s in your compressed air is going to get on whatever it’s coming in contact with.  That means if you’re blowing dirt or water off a part with a Safety Air Gun, you could be blowing dirt, or water ONTO it if you’re not using proper filtration.  Clean, moisture free air is a MUST for a lot of Line Vac Air Operated Conveyor applications where exclusion of contamination (food and pharma, we’re looking at you) is critical.  It’s also quite important to Cabinet Cooler System applications – dust, water, and electronics DON’T mix.

That’s why all EXAIR Intelligent Compressed Air Product Kits include a Filter Separator with a particulate element to remove solids, and a centrifugal element that spins out any moisture in the air flow supplying the product.  Sometimes, though, another  contaminant may be present, and may need to be addressed: oil.

Oil is often introduced into a compressed air system on purpose, via a lubricator installed in the supply line to pneumatic tools, to keep their moving parts, well…moving.  This is generally not a problem, as long as the lubricator’s downstream line only leads to said tools.  The most common method for UNWANTED oil to enter is from the compressor.  This happens when internal parts start to wear (like the piston rings of a reciprocating compressor,) allowing oil from the gearbox into the air side.

Just as water & dirt in your air will get on whatever you’re blowing onto, so will oil.  That’s where our Oil Removal Filters come in.  The coalescing element removes any trace of oil from the air flow, and also provides additional particulate filtration to 0.03 microns.

When properly installed downstream of an Automatic Drain Filter Separator (left,) an Oil Removal Filter (center) will provide clean, oil free air to the Pressure Regulator (right) and all downstream components.

If you want to get the most out of your compressed air system and the devices it operates, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Compressed Air Filters: What They Are, And Why They Matter

The first time I ever bought a brand new car was in 1995…it was a Ford Escort Wagon. My plan was to pay it off quick and run the tires off it. Well, I DID actually put new tires on it several times over the 11 years and 200,000 miles I had it. But, aside from fuel & tires, that car cost me less than $2,000 in repairs over all that time…an achievement that my mechanic said was due largely to the aforementioned planned maintenance, which largely consisted of regular oil changes, which, of course, included a new oil filter, every 3,000 miles. For the record, I didn’t run the wheels off it; I sold it when I took a job that included a company vehicle. Also for the record, I found out the fellow I sold my car to was still driving it after I left that job (and company vehicle.) He, too, believed in regular oil changes, and he might still have that 1995 Escort on the road for all I know.

So, yeah, I’m a big believer in the importance of fluid filtration.  If you’re a regular reader of the EXAIR Blog page, you likely are too.  The two main culprits that cause the most problems in a compressed air system are solid particulates and water.  These are easily addressed with a Filter Separator, like EXAIR Model 9004 Automatic Drain Filter Separator.  It has a 5 micron particulate element, and a centrifugal element that imparts a spinning motion to the air flow.  Since water is denser than air, any droplets of moisture are “flung” to the inside wall of the bowl, while the moisture-free air continues on through the discharge.

 

The particulate element captures solids larger than 5 microns, and the centrifugal element eliminates moisture.

Another common impurity in compressed air is oil.  Since oil-less compressors came along, this is easy to eliminate at the source…literally.  However, for other types of compressors (piston types in particular,) as they age, the oil that lubricates the moving parts can seep by the piston rings and get to the air side.  Oil doesn’t carry the same wear and corrosion problems that dirt & water do, but it causes particular problems in air conveyance and blow off applications: anything in your air is going to get on your product.  Ask any paint booth operator, for example, what happens when a metal surface hasn’t been cleaned of all traces of oil.  It really does look a “fish eye.”

The most common type of oil removal filter uses a coalescing element.  Oil entrained in pressurized gas flow isn’t as dense as water – so centrifugal elements won’t remove it – and it tends to act like particulate…but very fine particulate – so typical sintered particulate elements won’t remove it.  Coalescing elements, however, are made of a tight fiber mesh.  This not only catches any trace of oil in the air flow, but also much finer particulate than those sintered elements.  EXAIR Oil Removal Filters, like the Model 9027 shown below, provide additional particulate filtration to 0.03 microns.  That’s some pretty clean air.

The coalescing element of an Oil Removal Filter catches oil and very fine particulate.

For best results, we recommend both the Filter Separator and Oil Removal Filter.  Make sure you install the Filter Separator upstream of the Oil Removal Filter…that way, its 5 micron element catches all the “big” particles that would quickly clog the very fine coalescing element, necessitating an element replacement.  In fact, this arrangement will allow the Oil Removal Filter to operate darn near indefinitely, maintenance free.

If you have questions about keeping your compressed air clean, moisture free, and oil free, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Products Built to Last and Maintenance Free

As an avid outdoors man, I have learned a lot about myself during these days of quarantine and social distancing; mainly I don’t quarantine very well. With all the climbing gyms closed, traveling strongly discouraged, and social distancing in place my  lifestyle has been brought to a grinding halt much like many of us. opening up, which will be good for all of us. 

So, in place I have taken upon myself to learn a new hobby that I can do solo and safely. In the past weeks I have spent learning about mountain biking and all that comes with it. This includes the maintenance required to work on a bike, specifically the front derailleur which controls the front major gear changes (and gets damaged if crashed). Realigning the front derailleur is one of the hardest fixes that one can do on a bike as it has three different adjustments that need to be made at the same time. Thus, I embarked on a week long project of learning how to make the adjustment and man was it frustrating.

Performing tricky maintenance can be one of the most frustrating and stress inducing things when all you really want is for something to work without any hassle. Whether its hours just trying to figure out what the issue is or actually fixing it, let’s be honest, it never goes as planned. The same can be said for maintenance on things such as compressors, cars, and production equipment. Here at EXAIR we strive to eliminate this frustration and hair pulling maintenance and replace it with maintenance free products.

EXAIR’s lines of compressed air products such as our Vortex Tubes, Super Air Amplifiers, and Super Air Knives have no moving parts. No moving parts means no wear down parts and no wear down parts means little to no maintenance. Besides the occasional air filter element change out or something getting lodged inside the product EXAIR’s compressed air products will run almost indefinitely as long as they are supplied with a source of compressed air, typically run through a standard 5 micron filter separator. 

Although you cannot really prevent dirt from collecting in a filter separator (that is, in fact what they are meant to do) you can prevent dirt, dust, and debris from getting into your products by using one of EXAIR’s Filter Separators. Filter Separators remove water condensate, dirt, dust, and debris from your compressed air line before it enters your compressed air product. This prevents the particles from disrupting small air outlets or lodging in the small pathways inside our compressed air products and keeps the product running like new.

All in all, maintenance is not fun to have to deal with and can be costly at times. By using EXAIR’s engineered compressed air products you can eliminate at least one thing to worry about on your list of maintenance that needs to be performed. With a little bit of preventive measures you can keep our products running like new for years and years.

If you have any questions or want more information on any EXAIR’s of our products, give us a call, we have a team of application engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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