Tag: air system cleanliness

Why are There so Many Compressed Air Filters?

Published on by Jordan T ShouseLeave a comment

Compressed Air Filters are a necessary thing in modern manufacturing, and here at EXAIR we provide them in most kits. But what filter do you use, cleanliness standards require a variety of impurities to be removed, including oil mist, vapors and particulate matter. Impurities can enter the compressed air stream in several different ways. Intake air can introduce dust or debris particulates, rusted pipes can introduce rust and scale particulates. Oil and liquid vapors are often a consequence of using oiled compressors and must be filtered out before the compressed air can be used. There are distinct cleanliness standards for different compressed air applications, but the presence of impurities can exceed those standards, leading to damaged products or unsafe air. Filters fall into three categories: coalescing filters, absorption filters and the dry particulate filters. While each type ultimately produces the same result, they each operate on different principles.

Particulate Filters

Dry particulate filters are commonly used to remove desiccant particles after an in process dryer. But here at EXAIR we recommend using them at the point of use also to remove any rust particles from the compressed air before It’s used to clean, dry or cool in your process. Dry particulate filters function similar to a coalescing filter, catching particles within the filter media / or element.

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

Coalescing Filters

Coalescing filters are primarily used for removing liquids and aerosols, if used in line with a particulate filter is the coalescing filter should be second in line. Small condensations are caught in a filter media and merged into larger drops that are then taken out of the filter typically into a bowl.  Most of the liquid coalescing filters remove is water and oil. Coalescing filters remove most impurities, reducing particulate levels down to 0.1 micron in size and liquids down to 0.03 micron.

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 absorption 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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Compressed Air System Equipment

Published on by bdwagesLeave a comment

Compressed air is a valuable utility and understanding what makes up a solid system is very important. Most all manufacturing facilities have a demand for compressed air, so today we’ll discuss how when managed well, and with the proper equipment, how valuable this utility can be.

The equipment begins with the compressor. Specifying which compressor is best for you is genuinely specific to your needs, and many times even your geography. How many “users” of the air, the distance the air has to travel, how many and how sharp of turns need to be made are all specific to your building and setup. Drastic temperature changes, night and day, and many times summer to winter, can effect the compressor as well. Here is a list of things to consider when purchasing or upgrading the compressor itself:

  1. What is the actual air requirement? (SCFM) – as a rule of thumb – every 1 HP = 4 SCFM
  2. How many shifts, and do these shifts vary in air consumption?
  3. Average and Maximum Flow requirements
  4. What about leaks?
  5. What about the future?
  6. What is the highest pressure needed and why?
  7. How far away form the source are the users?
  8. Would a receiver tank/intermittent storage in the loop benefit your situation?

Compressor: Once you fully have a grasp of your demand, you can now move on to the compressor. There are 5 main types of compressors. One of the most common is the single-stage lubricant injected rotary screw compressor. This compressor is also offered in 2 stage. The other 3 types are a) 2-stage double acting reciprocating compressor b) Lubricant free screw compressor and c) Centrifugal 3-stage compressor. Each of these compressors have their own unique characteristics, benefits and faults. We highly recommend getting a local Air compressor company or professional involved to ensure the correct type and size.

Dirty Inlet Filter: Once the compressor is specified, you will need to ensure you have the best solution for dirty, ambient air being pulled into the compressor. The air coming out, begins with the air coming in, so this filter needs careful consideration based upon your individual ambient conditions. We’ve all heard the saying “garbage in – garbage out”… This filter should be checked, washed or changed often.

Receiver tank: The compressor(s) feed into a receiver tank. Many times this is call the Control Receiver, or the wet tank or cooling tank. Receiver tanks take in the air from the compressor and hold it under pressure for future use. These tanks reduce the cycles on the compressor, and prevents excessive loading and unloading in the system. These are not used on every system, but should be.

Dryer: Regardless of where you are in the world, all atmospheric air has some amount of vapor which will begin to condense into water when the air is cooled to the saturation point (This saturation point is better known as the dew point). The amount of moisture in the air depends on the temperature and relative humidity. As a rule of thumb, the moisture in the air will double for every 20°F increase in temperature. Your dryer should be able to dry the air to a dew point that is at least 18°F below the lowest temperature at the use point of the air. The size and amount of dryers is completely dependent on your companies needs.

Coalescent filter: Right after the dryer, it is recommended to put this type of filter to remove any other condensate, oils, or lubricants from the compressor. Unwanted oil in in the system can effect the machines and tools being used with the air.

Once your pipes have been laid to your point of use areas be it a machine or tools, you will want to have another filter at the point of use. Regardless of the age of your system, piping corrosion will happen leading to particulate in your air lines. You will want to filter this out prior to the final use of the air. The style and size of these filters should be determined at the point of use for the air. If your end use utilizes an EXAIR product – we recommend using our Automatic Filter Separators.

As the final step prior to use, it is recommended to have a pressure regulator and gauge on the line. Over time, every system will deplete air with small leaks, added users, or dirty filters. The most common cause of failure with EXAIR products, is actually lack of the appropriate air at the point of use.

Please keep in mind that this is a fairly simplistic explanation of a common Compressed Air System. Some systems have multiple receiving tanks, refrigerant coolers, dryers, and many different types of filters. The main goal is having enough clean, dry air to ensure that machines and tools function at peak performance.

Thank you for stopping by,

Brian Wages
Application Engineer
EXAIR Corporation
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Filtered Compressed Air is the Best Compressed Air: Three Filter Types

Published on by Jordan T Shouse1 Comment

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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Find us on the Web 
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Twitter: @EXAIR_JS

Compressed Air Filters: What They Are, And Why They Matter

Published on by Russ BowmanLeave a comment

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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