What’s The Big Deal About Clean Air?

Compressed air isn’t called manufacturing’s “Fourth Utility” (the first three being electricity, water, and natural gas) for nothing. Pneumatic tools are popular because they’re often so much lighter than their electric counterparts. Compressed air can be stored in receiver tanks for use when other power supplies are unavailable or not feasible. Many compressed air operated products can be made to withstand environmental factors (high/low temperature, corrosive elements, atmospheric dust, oil, other contaminants, etc.,) that would make electric devices very expensive, unwieldy, or impractical.

One of the most valuable considerations, though, is that your compressed air system is, by and large, under your control.  The type and capacity of your air compressor can be determined by your specific operational needs.  The header pressure in your supply lines is based on the applications that your air-operated devices are used for.  And the performance & lifespan of every single component in your compressed air system is determined by the care you take in maintaining it.

I covered the importance of compressed air system maintenance in a blog a while back…today, I want to focus on clean air.  And, like the title (hopefully) makes you think, it’s a REALLY big deal.  Consider the effects of the following:

Debris: solid particulates can enter your air system through the compressor intake, during maintenance, or if lines are undone and remade.  If you have moisture in your air (more on that in a minute,) that can promote corrosion inside your pipes, and rust can flake off in there.  Almost all of your air operated products have moving parts, tight passages, or both…debris is just plain bad for them.  And if you use air for blow off (cleaning, drying, etc.,) keep in mind that anything in your compressed air system will almost certainly get on your product.

Your compressed air system may be equipped with a main filter at the compressor discharge.  This is fine, but since there is indeed potential for downstream ingress (as mentioned above,) point-of-use filtration is good engineering practice.  EXAIR recommends particulate filtration to 5 microns for most of our products.

Water: moisture is almost always a product of condensation, but it can also be introduced through faulty maintenance, or by failure of the compressor’s drying or cooling systems.  Any way it happens, it’s also easy to combat with point-of-use filtration.

EXAIR includes an Automatic Drain Filter Separator in our product kits to address both of these concerns.  A particulate filter element traps solids, and a centrifugal element “spins” any moisture out, collecting it in the bowl, which is periodically drained (automatically, as the name implies) by a float.

Point of use filtration is key to the performance of your compressed air products, and their effectiveness. Regardless of your application, EXAIR has Filter Separators to meet most any need.

Oil: many pneumatic tools require oil for proper operation, so, instead of removing it, there’s going to be a dedicated lubricator, putting oil in the air on purpose.  Optimally, this will be as close to the tool as possible, because not all of your compressed air loads need oil…especially your blow offs.  If, however, a blow off device is installed downstream of a lubricator (perhaps due to convenience or necessity,) you’ll want to do something about that oil. Remember, anything in your system will get blown onto your product.

If this is the case, or you just want to have the cleanest air possible (keep in mind there is no downside to that,) consider an EXAIR Oil Removal Filter.  They come in a range of capacities, up to 310 SCFM (8,773 SLPM,) and the coalescing element also offers additional particulate filtration to 0.03 microns.

In closing, here’s a video that shows you, up close and personal, the difference that proper filtration can make:

If you’d like to discuss or debate (spoiler alert: I’ll win) the importance of clean air, and how EXAIR can help, give me a call.

Russ Bowman
Application Engineer
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Oil Removal Filters – Keeping Compressed Air Clean

Compressed air filters help to keep the air clean and condensate free to protect equipment from dust, dirt, pipe scale, oil and water. Even though the compressed air system will typically have a main dryer, additional treatment is often necessary. For this discussion, we will focus on the oil removal process and filter type.

After the compressed air has passed through a particulate filter, the dirt, dust and water droplets have been removed.  Oil that is present is much smaller in size, and mostly passes though the particulate filter.  The installation of a coalescing filter will provide for the removal of the majority of the fine oil aerosols that remain. The coalescing filter works differently than the particulate filters. The compressed air flows from inside to outside through the coalescing filter media. The term ‘coalesce’ means to ‘come together’ or ‘form one mass.’  The process of coalescing filtration is a continuous process where the small aerosols of oil come in contact with fibers of the filter media. As other aerosols are collected, they will join up and ‘come together’ and grow to become an oil droplet, on the downstream or outside surface of the media.  Gravity will then cause the droplet to drain away and fall off the filter element.

9005
Example of a 0.03 Micron Coalescing Oil Removal Filter

Some important information to keep in mind –

  • Change the filter regularly, not just when the differential pressures exceeds recommended limits, typically 5 PSI
  • Coalescing filters will remove solids too, at a higher capture rate due to the fine level of filtration, using a pre-filter for solids will extend the life
  • Oil free compressors do not provide oil free air, as the atmospheric air drawn in for compression contains oil vapors that will cool and condense in the compressed air system.

If you would like to talk about oil removal filters or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Compressed Air Filtration – Particulate, Coalescing, and Adsorption Types

Compressed air systems will contain contaminants that can lead to issues and increased costs through contamination of product, damage to the air operated devices, and air line clogging and restriction. Proper air preparation is critical to optimizing performance throughout the plant operations.

Because there are different types of contaminants, including solid particles, liquid water, and vapors of water and oil, there are different methods of filtration, each best suited for maximum efficiency in contaminant removal.

Particulate Filters – The compressed air flows from outside to inside of the filter element. The compressed air first passes through a baffle arrangement which causes centrifugal separation of the largest particles and liquid drops (but not liquid vapors), and then the air passes through the filter element.  The filter element is usually a sintered material such as bronze.  The filter elements are inexpensive and easy to replace. Filtration down to 40-5 micron is possible.

9001
Particulate Type Filter with Sintered Bronze Element

Coalescing Filters – This type operates differently from the particulate type.  The compressed air flows from inside to outside through a coalescing media. The very fine water and oil aerosols come into contact with fibers in the filter media, and as they collect, they coalesce (combine) to form larger droplets towards the outside of the filter element. When the droplet size is enough the drops fall off and collect at the bottom of the filter housing.  The filter element is typically made up of some type glass fibers.  The coalescing filter elements are also relatively inexpensive and easy to replace. Filtration down to 0.01 micron at 99.999% efficiency is possible.

9005
Coalescing Type Filter with Borosilicate Glass Fiber Element

Adsorption Filters – In this type of filtration, activated carbon is typically used, and the finest oil vapors, hydrocarbon residues, and odors can be be removed.  The mechanism of filtration is that the molecules of the gas or liquid adhere to the surface of the activated carbon.  This is usually the final stage of filtration, and is only required for certain applications where the product would be affected such as blow molding or food processing.

When you work with us in selecting an EXAIR product, such as a Super Air Knife, Super Air Amplifier, or Vortex Tube, your application engineer can recommend the appropriate type of filtration needed to keep the EXAIR product operating at maximum efficiency with minimal disruption due to contaminant build up and unnecessary cleaning.

If you have questions regarding compressed air filtration or any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Regulators and Filters for Compressed Air

I would like to dive into the realm of filters and regulators. Majority of EXAIR products use compressed air to coat, conserve, cool, convey or clean. So, to keep the product running efficiently, we need to supply them with clean, dry, pressurized air. We offer a line of filter separators, oil removal filters, and regulators that can supply enough pressure and flow to keep the EXAIR products performing for a very long time. If we look at each individual item, we can see how they can play an important part in your compressed air system.

Regulators are used to control the amount of air pressure being supplied to your EXAIR products. This is important if you are trying to control the flow, force, and/or conveyance rate. One issue with regulators is “droop”. Droop is the amount of pressure drop when you flow through a regulator. If you set the pressure of a regulator with no flow, to let’s say 80 psig (5.5 barg). Once you start flowing, you will see the downstream pressure fall. This is dependent on the size of the regulator and the valve inside. This is very important because if you need 80 psig (5.5 barg) downstream of the regulator feeding an EXAIR product and the droop brings it to 30 psig (2 barg), you will not have enough flow for your EXAIR product, losing performance. EXAIR recommends a specific regulator for each of our products. We tested our products with the recommended regulators to make sure that you are able to get the best performance. If you do use another manufacturer’s regulator, make sure you are able to flow the correct amount of air at the pressure you need. Not all ¼” regulators flow the same.

Pressure Regulator
Pressure Regulator

Filter separators are used to remove liquid condensate and contamination from the compressed air stream. They have a 5 micron filter and work very well if you get a slug of water or oil into your compressed air system. They use mechanical separation to remove the large particles of dirt and water from the air stream. Most facilities have some type of compressed air dryer in their system. This will dry the compressed air. But, if a system failure occurs, then water, oil, and dirt are pushed into the compressed air lines and perhaps into your EXAIR products. Even if you have good quality air, it is important to keep your products protected. An ounce of prevention ….

Oil Removal Filter
Oil Removal Filter

 

The oil removal filters are used to keep the compressed air even cleaner yet. They work great at removing very small particles of dirt and oil. Without an oil removal filter, dirt particles and oil particles can collect in “dead” zones within the compressed air lines. Over time, a tacky glob forms. As it grows, it can break off and get into the air stream affecting pneumatic devices. The oil removal filter will be able to help eliminate the long term effects in your compressed air system. As a note, oil removal filters are not great for bulk separation. If you have a system with lots of water, you will need a filter separator in front of the oil removal filter to optimize the filtration. With the oil removal filters, the media is a barrier to collect the small particles of dirt and oil. If a slug of water or oil tries to go through, it will block a portion of the element off until it is forced through. This will increase the velocity and pressure drop of the element. With the high velocity, as the slug makes its way through the media, it can spray, re-entraining the liquid particles.

Now that we went through our pneumatic products, how do we use them together to get the best supply of compressed air? With both types of filters, we always want them to be upstream of the regulator. This is because the velocity is lower at higher pressures. Lower velocities mean smaller pressure drops which is good in filtration. If we can analyze the compressed air systems, I would like to categorize it into a good and premium quality. To supply a good quality of compressed air, you can have the compressed air run through the filter separator then a regulator. To produce the premium quality of compressed air, you can have your compressed air run through the filter separator, the oil removal filter, and then the regulator. With clean quality air, your EXAIR products will provide you with effective, long-lasting performance without maintenance downtime.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Reclassifying Mufflers

Have you ever walked into an industrial plant and noticed a “fog” in the air? If they have pneumatic equipment, then it is a good chance that it is an oil mist. With many pneumatic devices, they need oil to lubricate the o-rings and cylinders for functionality and life. This is generally done with a lubricator. A lubricator puts a small amount of oil in the compressed air line to coat the inside of valves and cylinders. The problem becomes when the valve switches or the cylinder retracts, the excess air is exhausted into the atmosphere. And with that air, there is a fine mist creating the “fog”.

Reclassifying Muffler
EXAIR Reclassifying mufflers are available from 1/8 NPT through 1 NPT

 

Most pneumatic equipment will have some type of muffler to reduce the noise. Typically they are a sintered bronze muffler. They work well in noise reduction, but they do not capture the oil. OSHA (Occupational Safety and Health Association) has a requirement for operator’s exposure. Under the standard 29CFR 1910.1000, the cumulative exposure for a worker is 4.32 PPM (parts per million) for an 8 hour shift and a standard 40 hour week. As EXAIR Corporation is a leader in safety with compressed air systems, we created a muffler with an oil coalescer, or our Reclassifying Muffler. The Reclassifying Muffler will be able to accomplish two things: 1. reduce the noise level, and 2. remove the oil from the exhausted air. The complex matrix of fibers absorbs the noise caused by the pressure relief. Also, this same complex matrix of fibers creates a tortuous path for the oil particles. It will collect on the fibers and coalesce into larger particles. The larger oil particles will now be able to have gravity move the residual oil down the side of the Reclassifying Muffler. At the bottom, we have a sump that will contain the waste oil and a ¼” tube adaptor to discard it safely away. We have a range of sizes from 1/8” npt to 1” npt depending on the amount of exhaust air flow. In some instances, you can manifold the lines together to use one larger Reclassifying Muffler. An instance of this would be many small valves inside an electrical cabinet that would need to have the exhaust air removed. With our range of Reclassifying Mufflers, you will not have to walk around in the fog.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Why 5 PSIG Matters

Last week I pointed out the important locations for measuring your compressed air system pressure throughout your compressed air system.   One of the critical points to measure system pressure was before and after each filter.  This leads into another question that I receive every once in a while, “How do I tell when the filter needs to be changed?”  The answer to this is easy, when you see more than a 5 PSIG pressure drop across the filter.  This means that the element within the filter has become clogged with sediment or debris and is restricting the volume available to your downstream products.

Filter
EXAIR 5 micron Auto Drain Filter Separator

 

This can lead to decreased performance, downtime, and even the possibility of passing contaminants through the filter to downstream point of use components.  In order to maintain an optimal performance when using EXAIR filter separators and oil removal filters, monitoring the compressed air pressure before and after the unit is ideal.

Replacement filter elements are readily available from stock, as well as complete rebuild kits for the filter units. Changing the filters out can be done fairly easily and we even offer a video of how to do it.

The life expectancy of a filter element on the compressed air is directly related to the quality of air and the frequency of use, meaning it can vary greatly.  If you tie a new filter onto the end of a compressed air drop that has not been used in years, you may get a surprise by the filter clogging rather quickly.   However, if you maintain your compressor and your piping system properly then the filters should last a long time. Generally we recommend checking your filters every 6 months.

If you have questions about where and why to filter your compressed air contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Video Blog: Effectiveness of Filtering Your Compressed Air

The video below will give a brief demonstration on the importance of point of use filtration in order to remove unwanted material such as water, scale, particulate and oil from your compressed air stream. Point of use or end-use filtration will keep your air clean and your compressed air products running smooth.  If you have any comments or questions, please feel free to contact us.

 

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF