Tag: compressed air filter

Types of Filters Used in a Compressed Air System

Published on by Tyler DanielLeave a comment

Most of EXAIR’s line of Intelligent Compressed Air Products have no moving parts and require no maintenance. The caveat to the “no maintenance” aspect is proper filtration at the point of use. Many products have very tight orifices that could get clogged from any contaminants such as particulate, condensate, and lubricant. EXAIR recommends point of use filtration to be installed just upstream of any EXAIR Product for this purpose.

There are three primary types of compressed air filters: particulate, coalescing, and adsorption. Each have their own inherent characteristics and can be used in conjunction with one another. Each style is used to handle a different form of contaminant that’s present within the distribution system of your compressed air supply.

9001
EXAIR Model 9001 Auto-Drain Filter

Particulate filters – Particulate filters are available with different filtering mechanisms that allow you to control the particulate size that will be filtered out. The higher the level of filtration, the greater the pressure drop you’ll experience at the outlet of the filter. Styles are also available with either a polycarbonate bowl or metal bowls, depending on the application and environment.

Any filter with a polycarbonate bowl should have a metal guard on the outside to provide protection for personnel should a failure occur. In these styles of filters, compressed air is forced through a filter element that blocks any particulate contained within the air supply.

These filter elements are generally a sintered bronze material with filtration levels from 40-5 micron possible. Over time, the filter elements can clog and increase the pressure drop at the discharge of the filter. They’re relatively inexpensive and should be replaced yearly to maintain optimum performance and mitigate pressure drop. They also remove liquid drops as well from the air supply, containing them within the bowl. Styles with both manual-drains and automatic-drains are available that will drain the bowl of excess moisture automatically through the bottom of the filter.

9005
EXAIR Model 9005 Oil Removal Filter

Coalescing Filters – The coalescing filter is used to remove very fine water vapor as well as any residual oil. These filters are highly recommended to be installed just prior to any dryer that contains a media that would be compromised by any lubricant passing through it. Coalescing filters utilize an element typically made up of glass fibers that “coalesce”, or combine, the fine water vapor and oil aerosols until the droplet size becomes large enough that it drops off into the bowl or filter housing. With a coalescing filter, the most common cause of pressure drop increase is due to particulate clogging the filter element. Because of this, a particulate filter should always be installed just prior to any coalescing filters.

Adsorption Filters – The final type of compressed air filter is the adsorption filter. Where the particulate filters can remove the majority of contaminants and the coalescing filters the residual oil, they are not capable of removing lubricant vapors or oil. That’s where the adsorption filter comes in. In addition to removing the finest oil vapors, they also can eliminate odors from the compressed air supply. The oil vapors and odors adhere to activated carbon within the filter, removing them from the air supply. These filters are commonly found within the food processing industry, where any contaminants in the air supply could impact the integrity of the product.

EXAIR has a line of Automatic Drain Filter Separators and Oil Removal Filters, available from stock, to make sure the quality of your air supply is sufficient for proper operation of any EXAIR product. Feel free to give us a call and any of our Application Engineers will be happy to assist you.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
X: @EXAIR_TD

Why you should use point of use Filtration!

Published on by Jordan T ShouseLeave a comment

First, let’s think about a gas station. When the fuel delivery truck fills the stations’ tank, the fuel is passed through a filter to make sure it’s free of water and debris. Then, as you are pumping it into your car, it passes through another filter! And then, in your car, the fuel is passed though another filter before it goes to your engine! Filtering your compressed air supply at several points is just as important, and a single filter at the compressor isn’t enough! That is where the point of use filters comes into play!

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 similarly 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 particulates

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 our compressed air filter options here!

Jordan Shouse
Application Engineer

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Why – And Where – Do You Need Filtration In Your Compressed Air System?

Published on by Russ BowmanLeave a comment

Good engineering practice, and proper system design, call for filters at various points in a compressed air system. I’m going to go through these along the path that compressed air follows, from being drawn from atmospheric pressure in to the compressor, to being returned to atmospheric pressure at its point of use.

Any air compressor is going to have an intake filter. The small “pancake” compressor in my garage has a little disc looking thing with a screen whose mesh is about the same as my house’s window screens. Larger industrial air compressors have cartridge-type filters that impart a spiral motion to the incoming air. That motion actually removes most of the incoming particulate, while the rest gets caught in the pleats of the fiber element. The main purpose for an intake filter is to protect the compressor’s internal components. Solid particulates can really do a number on the high speed, close tolerance moving parts inside a compressor, in a hurry.

All the other filters you might find are there to ensure proper operation of the rest of your compressed air system:

  • Distribution. No intake filter is going to be 100% efficient, nor will it remove especially fine particulate that doesn’t present a real risk of damage or wear to the compressor. Intake filters also will not remove oil (or oil vapor) and water (or water vapor). The compressor itself can actually add contaminants to the compressed air, in the form of wear particles (remember those close tolerance moving parts I mentioned above?) and oil carryover. All of these contaminants will, however, be detrimental to the pipe & fittings that takes the newly compressed air to where it’s used. They can cause a buildup on the inner walls of the piping that inhibits flow. Water causes the pipe to start rusting from the inside out. When that rust scale breaks loose, it can clog, foul, or damage valves, fittings, and other control devices in the distribution header. Ideally, you’ll use filtration with a particulate element, a centrifugal element for water, and a coalescing element for oil/oil vapor (if needed…this isn’t a concern for oil-free compressors, for example).
  • Distribution, part 2. If your facility is large enough, you may need filtration at strategic locations…perhaps one for the air going to the machine shop, another for an area with machinery equipped with pneumatic cylinders, another for an assembly area where pneumatic tools are used, etc. The type(s) of filter(s) you use at those points will be determined by what the air is used for. If you know you have oil carryover from your compressor, you probably want a coalescing filter on the line to Safety Air Guns that blow off parts before painting. You don’t need them on lines going to your pneumatic tools, though…that carryover will likely help supplement the point-of-use lubricators that they use.
  • Point-of-use. Good engineering practice calls for a final stage of filtration, located as close as practical to the air operated device(s). EXAIR includes a Filter Separator with a 5 micron particulate element and a centrifugal element for water with all of our product Kits. Oil Removal Filters are also available for oil/oil vapor. They also provide additional particulate filtration to 0.03 microns.
EXAIR offers a variety of Filter Separators (left), Oil Removal Filters (middle), and Pressure Regulators (right) that are suitable for a wide range of point-of-use compressed air applications. Contact an Application Engineer for more details.

At EXAIR, we’re here to make sure you get the most out of your compressed air system. If you’d like to find out more about filtration…or any other aspect of air treatment (drying, regulating, cooling, etc.)…give me a call.

Russ Bowman, CCASS

Application Engineer
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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

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS