The Importance of Compressed Air Filters

The last home I purchased had an all-seasons room, but the sellers told me the air conditioner that controlled the room temperature wasn’t working. When I moved in and tested the unit, the sellers were correct that it did not run. I started breaking it down and thought that maybe it could use a good cleaning. During this I found the filter, black and covered with pet fur. It was a washable filter so I cleaned it and let it air dry as I continued to clean remaining areas of the unit. When I put the filter back in and tried running the unit it was a miracle, it was running and producing cool air. I did nothing other than clean and clear the filter, no replacement parts, no tweaking and no repairmen.

I tell this story to many people now as it also relates to appliances, cars, lawn mowers and now I emphasize filters for compressed air systems. Using auto drain filters and oil removal filters is imperative to keeping your air clean before it gets to your tooling and equipment. Keeping water condensate and particulates contained to your filters is critical to the operation and life of your tooling and equipment. Older compressed air lines can begin to rust or corrode inside, creating scale which can jam and cause inefficiencies. Sediment and other contaminants will build up and could cause damage to your compressed air systems.

Good engineering practice calls for point of use filtration and moisture removal, such as that provided by EXAIR Filter Separators.

EXAIR carries multiple sizes and types of compressed air filters available from stock. Our Particulate and Coalescing filters can be found in our catalog and online (use the link above). If you have an application and need help selecting and sizing the right filter for your needs please contact one of our application engineers by calling 800.903.9247.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

Which Condensate Drain Is Best For Your Compressed Air System?

In a perfect world, your air compressor’s intake would be free of dirt, oil, and water. Proper maintenance (i.e., periodic cleaning and/or changing) of the intake filter will keep most of the dirt out. Oil and water vapor will pass right through…but that’s not the end of the world (however imperfect it may be); they’re easy to take care of later in the process.

Once these vapors have been compressed (along with all that air that was drawn in), it’ll go into the receiver (usually via an aftercooler in industrial compressors) where it cools down, and that vapor condenses. If it’s left alone, a couple of things can happen:

  • Standing water in the bottom of a steel tank will cause corrosion. This can be carried into your compressed air distribution system. Over time, it will also rust through the reservoir. You don’t want either of these things to happen.
  • Eventually, it’ll take up enough space that your reservoir’s capacity will effectively shrink. That can cause your compressor to cycle rapidly. You don’t want that either.

Even the smallest of compressors will have manual drain valves on the bottoms of their reservoirs. Users will simply blow down the gallon or so tank every so often and go about their business. The small amount of electrical power that the compressor will use to recharge those tanks makes this a perfectly acceptable practice.

In the perfect world I mentioned above, the large reservoirs on industrial air compressors could be drained of condensate in the same manner. There are a few challenges to periodic manual draining:

  • You could do it on a schedule, but varying levels of humidity mean different accumulation rates of condensation. Weekly blowdowns might be OK in the winter, but you may need to do it daily in the summer. And a couple days a week in the spring or fall. It can be a real chore to keep track of all of that.
  • A practiced operator may develop the skill to shut the valve immediately upon the last drop of condensate passing. More often than not, though, you’re going to lose some compressed air doing it manually.
  • File this under “don’t try this at home (or anywhere, really)” – an unfortunately all-too-common practice is to just leave a manual drain cracked open. It works, but it wastes compressed air. On purpose. There’s too much accidental waste to give this any further discussion. Just don’t do it.
  • Plain old forgetfulness, someone going on vacation, or even leaving the company could result in someone else noticing the compressor is frequently cycling (because the reservoir is filling with water…see above), and realizing nobody’s drained the tank in a while.

Again, these manual drains are quite common, especially in smaller air compressor systems…and so are the above challenges. I may or may not have personal experience with an incident similar to that last one. Good news is, there are automated products designed to prevent this from happening to you:

  • Timer drains are popular and inexpensive. They operate just as advertised: a programmable timer opens and closes the drain valve just like you tell it to. They don’t do anything at all to address the first two challenges above: they might blow down for longer than needed (and waste compressed air) or not long enough (and allow water to build up in the reservoir.) They come in two primary configurations:
    • Solenoid Valve: the timer energizes the valve’s coil to open the valve, and a spring shuts it when the timer runs out. Strainers will prevent blockage, and will need periodic maintenance.
    • Ball Valve: the timer operates an electric actuator to open & close the valve. The full port opening of the ball valve means a strainer is usually not necessary, so these are less maintenance intensive.
  • Demand (AKA “no waste” or “zero loss”) drains are actuated by the condensate level in the reservoir. They don’t discharge any of the reservoir’s compressed air, because they close before the last bit of water exits. There are a few common options to choose from:
    • Mechanical float drains can be internal or external…the latter is more common for use with air compressor reservoirs; the former is fairly standard with point-of-use filters (more on that later). When the liquid level rises, the float opens the drain; when liquid level drops, the float closes the drain…easy as that. They CAN be susceptible to clogging with debris, but many have screens to prevent or limit that.
    • Electronic types use a magnetic reed switch or capacitance device to sense the condensate level…so they require electric power.
    • These cost more than the timer types, though, and they’ve got a number of moving parts, so they can find themselves in need of repair. Inexpensive and user-friendly rebuild kits are oftentimes available, and many of these come with alarms to let you know when to use that rebuild kit.

Whether you have a manual, timer, or demand drain, keep in mind that some moisture can still be carried over, and rust/scale can still form in pipelines. Good engineering practice calls for point-of-use filtration, like EXAIR’s Automatic Drain Filter Separators and Oil Removal Filters. If you’d like to talk more about getting the most out of your compressed air system, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Optimize Your Intelligent Compressed Air® Products with EXAIR’s Accessories

EXAIR offers a wide variety of various accessories that can help you to better control and fine-tune any of your compressed air operated products. 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.

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. Particulate filters remove any suspended solids from the airstream, ensuring the tight orifices in the products remain free of debris. If your system has residual oil, this should also be removed with a coalescing filter. Check out this short video from my colleague, Brian Farno, that demonstrates these filters in action:

Controlling your compressed air pressure at the point of use is an excellent way of minimizing your compressed air usage. Pressure regulators are available to control the air pressure within the system and throttle the appropriate supply of air to any pneumatic device. As the last of the six steps to optimizing your compressed air system, controlling air at the point of use can often be overlooked. using them to minimize your pressure can result in dramatic savings to your costs of compressed air. As pressure and flow are directly related, lowering the pressure supplied results in less compressed air usage. EXAIR recommends operating your Intelligent Compressed Air Products at the minimum pressure necessary to achieve a successful application. If you notice a desirable result at a pressure of 60 PSIG, or even less, there’s no need to run full line pressure. In-line point of use pressure regulators are the simplest and most reliable way to allow you to dial down to the pressure to any compressed air operated product.

Taking this idea of minimizing air usage one step further, you can achieve even greater savings by simply turning the air off when not needed. The most basic option for turning off the air supply is a simple manual valve. EXAIR offers a range of various sized valves to allow you to do just that.

This process can also be automated as well. If you’d like to automate the control of your blowoff, EXAIR offers solenoid valves that can tie into your existing PLC and eliminate unnecessary air usage. For those that want a solution ready to go right out of the box, EXAIR’s Electronic Flow Controller utilizes a photoelectric sensor and solenoid valve tied to a timer that allows you to shut off the air supply when a part or component is not present. This can lead to dramatic air savings in many applications where parts are traveling along a conveyor.

Once you’ve selected an engineered compressed air nozzle for your blow off application, you’ll likely need a solution to mount and position it as well. Here’s where EXAIR’s Stay Set Hoses and Magnetic Bases come into play. EXAIR’s Stay Set Hoses are available from 6”-36” in length with ¼ NPT male threads on each end, or a ¼ NPT male on one end and 1/8 NPT female on the other. The Stay Set Hoses are rigid and allow you to maintain precise positioning of the blow off nozzle. The hoses have “memory” and will not creep or bend. They’re easily repositionable as well, making them an ideal solution for applications that may require frequent repositioning due to varying parts.

In addition to the Stay Set Hoses, EXAIR also has Magnetic Bases available as well. The powerful magnet permits both horizontal and vertical mounting. A manual valve is also included that will allow you to vary the force and flow. Magnetic bases are available with one or two outlets and can be combined with any of our nozzles and Stay Set Hoses to create your own customized blowoff system.

Regardless of your application, EXAIR has the products available from stock to help optimize your processes. These accessories allow you to help optimize the use of your blowoff products and ensure reliable, repeatable performance. If you’d like to discuss an application, give us a call.

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

Oil Removal Filters: Never First, Sometimes Last

If you have been around compressed air systems, our blogs, or even optimized installations of point of use compressed air products, you will see point of use filtration in place. These filters come in a plethora of sizes, shapes, and specifications. Here at EXAIR we recommend to always keep a point of use filtration solution in place. This would include an auto-drain filter separator, as well as an oil removal filter.

Oil Removal Filters

So why do we have two instead of one? Could you use just the oil removal filter rather than two? Well, the answer lies in an optimized installation that will also carry with it a lower total cost of ownership. The auto-drain filter separators from EXAIR have a filter element which takes the air to a 5 micron level of filtration. (Except for the model 9004 which filters down to 20 micron.) The Oil Removal Filters have a coalescing filter element which filters to a 0.3 micron level for the finest debris/mists that may be contained within the compressed air stream. One reason for the separation is when a system is oil-free, the finer filtration level may not be needed. Also, by catching the bulk of material with the standard auto-drain filter and then leaving the finer filter to catch the residual amounts liquid that had been finely atomized within the stream of compressed air. This finer filter costs more so using it to catch larger particulate and risking it becoming clogged quicker will increase the total cost of ownership of the point of use compressed air product it is hooked to, hence never first and sometimes last. After the point of use filtration then placing the point of use pressure regulator and solenoid valves are next. This is all a better way to reduce risk of these being damaged from dirt and contaminants in the air lines. Total cost of ownership reductions all point to a better sustainability of any product.

To better showcase the importance of filtration, here’s a brief video I did a while back that visualizes just what one can see out of a compressed air line with minimal moisture introduced.

As you can see, keeping the point of use air filtered protects your process and decreases the total cost of ownership for your compressed air point of use product. If you would like to discuss other ways we can improve efficiency within your facility and help ensure you are getting the longest life out of your products, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF