The Importance Of Air Compressor System Maintenance

 

It should go without saying, but proper operation of anything that has moving parts will depend on how well it’s maintained.  Compressed air systems are certainly no exception; in fact; they’re a critical example of the importance of proper maintenance, for two big reasons:

*Cost: compressed air, “the fourth utility,” is expensive to generate.  And it’s more expensive if it’s generated by a system that’s not operating as efficiently as it could.

*Reliability: Many industrial processes rely on clean or clean & dry air, at the right pressure, being readily available:

  • When a CNC machine trips offline in the middle of making a part because it loses air pressure, it has to be reset.  That means time that tight schedules may not afford, and maybe a wasted part.
  • The speed of pneumatic cylinders and tools are proportional to supply pressure.  Lower pressure means processes take longer.  Loss of pressure means they stop.
  • Dirt & debris in the supply lines will clog tight passages in air operated products.  It’ll foul and scratch cylinder bores.  And if you’re blowing off products to clean them, anything in your air flow is going to get on your products too.

Good news is, the preventive maintenance necessary to ensure optimal performance isn’t all that hard to perform.  If you drive a car, you’re already familiar with most of the basics:

*Filtration: air compressors don’t “make” compressed air, they compress air that already exists…this is called the atmosphere, and, technically, your air compressor is drawing from the very bottom of the “ocean” of air that blankets the planet.  Scientifically speaking, it’s filthy down here.  That’s why your compressor has an inlet/intake filter, and this is your first line of defense. If it’s dirty, your compressor is running harder, and costs you more to operate it.  If it’s damaged, you’re not only letting dirt into your system; you’re letting it foul & damage your compressor.  Just like a car’s intake air filter (which I replace every other time I change the oil,) you need to clean or replace your compressor’s intake air filter on a regular basis as well.

*Moisture removal: another common “impurity” here on the floor of the atmospheric “ocean” is water vapor, or humidity.  This causes rust in iron pipe supply lines (which is why we preach the importance of point-of-use filtration) and will also impact the operation of your compressed air tools & products.

  • Most industrial compressed air systems have a dryer to address this…refrigerated and desiccant are the two most popular types.  Refrigerant systems have coils & filters that need to be kept clean, and leaks are bad news not only for the dryer’s operation, but for the environment.  Desiccant systems almost always have some sort of regeneration cycle, but it’ll have to be replaced sooner or later.  Follow the manufacturer’s recommendations on these.
  • Drain traps in your system collect trace amounts of moisture that even the best dryer systems miss.  These are typically float-operated, and work just fine until one sticks open (which…good news…you can usually hear quite well) or sticks closed (which…bad news…won’t make a sound.)  Check these regularly and, in conjunction with your dryers, will keep your air supply dry.

*Lubrication: the number one cause of rotating equipment failure is loss of lubrication.  Don’t let this happen to you:

  • A lot of today’s electric motors have sealed bearings.  If yours has grease fittings, though, use them per the manufacturer’s directions.  Either way, the first symptom of impending bearing failure is heat.  This is a GREAT way to use an infrared heat gun.  You’re still going to have to fix it, but if you know it’s coming, you at least get to say when.
  • Oil-free compressors have been around for years, and are very popular in industries where oil contamination is an unacceptable risk (paint makers, I’m looking at you.)  In oiled compressors, though, the oil not only lubricates the moving parts; it also serves as a seal, and heat removal medium for the compression cycle.  Change the oil as directed, with the exact type of oil the manufacturer calls out.  This is not only key to proper operation, but the validity of your warranty as well.

*Cooling:  the larger the system, the more likely there’s a cooler installed.  For systems with water-cooled heat exchangers, the water quality…and chemistry…is critical.  pH and TDS (Total Dissolved Solids) should be checked regularly to determine if chemical additives, or flushing, are necessary.

*Belts & couplings: these transmit the power of the motor to the compressor, and you will not have compressed air without them, period.  Check their alignment, condition, and tension (belts only) as specified by the manufacturer.  Keeping spares on hand isn’t a bad idea either.

Optimal performance of your compressed air products literally starts with your compressor system.  Proper preventive maintenance is key to maximizing it.  Sooner or later, you’re going to have to shut down any system to replace a moving (or wear) part.  With a sound preventive maintenance plan in place, you have a good chance of getting to say when.

If you’d like to talk about other ways to optimize the performance of your compressed air system,  give me a call.

Russ Bowman
Application Engineer
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Image courtesy of U.S. Naval Forces Central Command/U.S. Fifth Fleet, Creative Commons License 

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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EXAIR Heavy Duty Vacuums Filtration: HEPA vs. Dry

 

I had a distributor that asked about the difference in filtration for the Heavy Duty HEPA Vac and the Heavy Duty Dry Vac. Besides the obvious thing that one is an “innie” and the other is an “outie” (HEPA filter is on the inside and Dry Vac filter is on the outside), there is a difference in the level of filtration. Model 901357 HEPA media is 99.97% efficient at 0.3 micron and Model 6804 media is 95% at 0.1 micron. What does this all mean?

In the simplest term, filtration is a method of separating. With air filters, we are separating particles from air. Particles, due to their mass and size, behave in certain ways as they pass through a fibrous media. The method of capturing the particles are done by 3 major mechanical methods:

  1. Inertial Impaction – Larger particles that are captured because they cannot follow the air stream around a fiber. It would be similar to hitting a golf ball into an oak tree. The tree is mostly open with air, but that golf ball always seems to hit that one little branch. The mass of the golf ball will not allow it to change direction as it comes towards the branch. Thus, we are looking for a lost ball. Captured!
  2. Direct Interception – Medium sized particles that can follow the air stream around some of the fibers. Because of the tortuous path and the inertial mass, they can contact fibers as they try to wind their way through the filter. This is similar to an extremely curvy road, and a vehicle with no brakes. As you start, you can keep on the road, but as the curves become sharper and tighter, your inertia will have you sliding off the road. Captured!
  3. Diffusion – Small particles with little mass are bounced around by the air molecules until they hit a fiber. It would be similar to a little clown car traveling on icy roads with truckers. If everyone had bumper pads, the little clown car will be bounced forward and backwards, side to side, and around and around. Whoops, you are off the road. Captured!
Diagram 1: Total filtration curve with individual mechanism by particle size
Diagram 1: Total filtration curve with individual mechanism by particle size

When we take an efficiency curve by particle size of an air filter, it resembles an inverted bell. In Diagram 1 above, you notice how each filtration mechanism is used to capture the particles by size. If you look closely, you will notice that the most penetrating particle size is between 0.2 and 0.3 micron. That means that if you go larger than 0.3 micron or smaller than 0.2 micron, the filter is more efficient. Say what? That is correct. With the examples above, a particle in the range of 0.2 to 0.3 micron has enough mass to resist the forces of other molecules but not enough mass to create a large inertia passing by or around the fibers of the filter.

Now lets apply these variables to our two types of filters. With Model 901357 HEPA media, the marker is 99.97% at 0.3 micron. Model 6804 media is 95% at 0.1 micron. If we apply the inverted curve analysis like in Diagram 1 to each of the filter medias, we can estimate the efficiency curve. As you can see in Diagram 2, the 901357 HEPA is more efficient at capturing particles than the 6804. So, when would you use the Heavy Duty Dry Vac or the Heavy Duty HEPA Vac? It is dependent on your dirty application and environment. If you require very fine filtration and/or very clean exhaust air, then I would recommend the Heavy Duty HEPA Vac. For most general industry environments, the Heavy Duty Dry Vac will work just fine. If you are still not sure, you can always contact our Application Engineers at EXAIR.

Diagram 2: Filtration Efficiency
Diagram 2: Filtration Efficiency

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

Heavy Duty HEPA Vac Reduces Dust When Vacuuming

hepafam_collection
EXAIR Heavy Duty HEPA Vacuum Systems

When selecting the proper EXAIR vacuum system for an application, several details are considered by our Application Engineers.  For example:

Does the vacuum need to vacuum liquids or solids?

If the need is to vacuum solid material, what is the approximate size of the material pieces?

How quickly does the material need to be vacuumed?

What is the compressed air supply available?

Is dust a major concern?

The last question becomes more relevant with finer material, especially dust or small dirt particles.  Many applications have a need for dust control and need a vacuum system capable of maintaining low dust levels.

The EXAIR Heavy Duty HEPA Vac was designed for this exact purpose.  With a HEPA filter that is tested in strict accordance to IEST-RP-CC-007 standards to provide a minimum of 99.97% filtration at the 0.3 micron level, the Heavy Duty HEPA Vac can provide an effective and highly efficient vacuuming method using only compressed air.

Fine Powder Hopper 2
Hopper used for fine powder collection

For example, in the fine dust collection hopper shown above, the hopper undergoes regular cleaning and maintenance which includes a thorough cleaning to remove any fine dust remaining in the hopper. This powder has a tendency to permeate the filtration used in most vacuums, and electrically powered units have continuously failed.

The Heavy Duty HEPA Vac is a perfect fit for this application need as it can provide adequate filtration, and it has no moving parts to wear out.

If you have a dusty or difficult vacuum application in need of a sustainable vacuum system, contact an EXAIR Application Engineer to discuss the Heavy Duty HEPA Vac.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

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

 

Continuous Improvement

I’m sure I have blogged about similar topics before but I’m going ahead with this anyway.   Have you ever bought something and after using it a few times say to yourself, I really wish they would have done this or I wish this had this feature.  I do that quite often, more often that my wife really cares for.  Normally it ends up with me being in the garage or the basement working on whatever it is for several hours and possibly even breaking whatever it was I was working on.  Well, I don’t just do that at home.

Two of our newest Industrial Housekeeping products were created from our own employees using them and seeing something that could make it better.   The easiest to see this with is our Chip Trapper System.

RDVFamily_300pxCT

Our Reversible Drum Vac Systems were around for a couple decades when someone decided to figure out a (patented) way to filter all the chips and solids out of the coolant we were processing.  So now, instead of just sucking the coolant out, we are able to filter the coolant and reuse it up to four times longer in our machines.

It is continuous improvements and being willing to listen to recommendations that make things like the Chip Trapper possible.  If you have one of our products and see a better idea, feel free to let us know, it may even be something that we could do on a custom basis for you.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Video Blog: How To Clean The Heavy Duty HEPA Vac Filters

The video below showcases how to clean the filter elements on the EXAIR Heavy Duty HEPA Vac.  This vacuum is ideal for areas where personnel are working and there is fine dust particulate that may be a respiratory hazard.  All EXAIR filters are tested 100%  in strict accordance to IEST-RP-CC-007 for minimum 99.97% filtration at the 0.3 micron level to meet the HEPA standard.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF