Top Ten Preventive Maintenance Items For Compressed Air Systems

Anything that has moving parts is, sooner or later, going to need maintenance.  One popular school of thought is “If it ain’t broke, don’t fix it.”  One major problem with that is, when it DOES break, you HAVE to fix it before you can keep using it.  That’s where preventive maintenance comes in: you get to choose WHEN you work on it.  This allows you to do that work at planned times that are convenient, and that have the least impact on your operations.

Patrick Duff, a production equipment mechanic with the 76th Maintenance Group, takes meter readings of the oil pressure and temperature, cooling water temperature and the output temperature on one of two 1,750 horsepower compressors. Each compressor is capable of producing 4,500 cubic feet of air at 300 psi. The shop also has a 3,000 horsepower compressor that produces 9,000 cubic feet of air at 300 psi. By matching output to the load required, the shop is able to shut down compressors as needed, resulting in energy savings to the base. (Air Force photo by Ron Mullan)

Compressed air systems not only have moving parts, they have parts that air moves through.  Periodic preventive maintenance can not only keep your system running; it’ll keep it running efficiently, meaning it costs less to operate.  Different types of air compressors in different environments will have different specific requirements, but following is a decent general list of ten items it might make sense to stay on top of:

  1. Intake vents. The air your compressor pulls in is going to go through some pretty tight passages.  Particulate can do some damage in there, and some of it will end up in your system where it’ll wreak havoc on your air operated equipment too.  Take care to keep your air compressor’s intake vents clean.  Many manufacturers and service professionals recommend a weekly inspection, and cleaning as needed.
  2. Lubrication.  Don’t be fooled by the term “oil-less” in an air compressor’s description.  This often means that there’s no oil in the air end.  The drive end is going to have bearings & moving parts that are lubricated.  Again, the compressor manufacturer will likely include periodicity and procedure for this in the manual.  This should include period oil (and oil filter) changes or grease renewal.
  3. Motor bearings.  Many air compressors are either direct coupled or belt driven by an electric motor.  Checking the temperature with a contact thermometer, or monitoring for changes in the ultrasonic signature (EXAIR Model 9061 Ultrasonic Leak Detector is a quick & easy way to do this) can give you indication of pending bearing failure.
  4. Belts.  Drive belts have a finite life span.  Vibration can also affect their tension and alignment.  If you have a belt driven compressor, check these out on a regular basis to make proper adjustments to the motor slide base.
  5. Lubrication, part 2. A friend of mine had a car that leaked oil.  He carried a couple of quarts with him…it was so bad that he had to add some every few days.  He called this replenishment system “self-changing oil”.  It isn’t.  Finding and fixing oil leaks is critical from both operational and housekeeping perspectives.
  6. Dryer.  Most industrial air compressors have a system that removes moisture from the compressed air before discharging into the system.  Different types of dryers require different types of maintenance.  Desiccant and deliquescent dryers, for example, will require media changes from time to time.  Refrigerated and membrane dryers will have parts like condensers or cartridges that you have to keep clean.  Keep up with the manufacturer’s recommendations, and you’ll have one less thing to worry about.
  7. Air leaks.  Air is free.  It’s literally everywhere, in great abundance.  COMPRESSED air is expensive, which makes leaks costly.  Good news is, compressed air leaks, like failing motor bearings (see #3, above) generate an ultrasonic signature, so you can get even more use out of an EXAIR Model 9061 Ultrasonic Leak Detector.  Find & fix leaks, and start saving money today.

    In addition to compressed air leaks, there are many industrial maintenance applications for Ultrasonic Leak Detectors. Contact an EXAIR Application Engineer for details.
  8. Filtration. Almost all pneumatically operated products work best with clean, moisture free air.  The compressor’s intake vents (see #1 above) and dryer (see #6 above) are there, primarily, to protect the compressor and the distribution system, respectively.  Good engineering practice dictates the need for point-of-use filtration.  EXAIR Automatic Drain Filter Separators have 5-micron particulate elements, and a centrifugal element to ‘spin’ out moisture.  Our Oil Removal Filters have coalescing elements to catch any trace of oil, and provide additional particulate filtration to 0.03 microns.  As filter elements capture debris, they start to clog, which reduces downstream pressure.  You should change these elements when the pressure drop across a filter reaches 5psi.
  9. Condensate drains.  Even the best dryers allow trace amounts of moisture into the compressed air system…even more so if the humidity in the area is high.  Properly designed compressed air distribution systems will have strategically placed drain traps to collect this moisture and rid the system of it.  They can be automatic, timed, or manual.  Inspect them periodically for proper operation
  10. Compressed air operated products.  Last but not least, make sure you keep up the maintenance on the tools and equipment that your compressed air system is there for in the first place.  Worn or damaged parts can increase consumption…and present very real safety risks.

EXAIR Corporation manufactures quiet, safe, and efficient compressed air products to help you get the most out of your compressed air system.  If you’d like to find out more, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Intelligent Compressed Air: Maintaining an Efficient Compressor System

compressor

The electrical costs associated with generating compressed air make it the most expensive utility in any industrial facility. In order to help offset these costs, it’s imperative that the system is operating as efficiently as possible. I’d like to take a moment to walk you through some of the ways that you can work towards making your compressed air system more efficient.

The first step you should take is to identify and fix any leaks within the distribution piping. According to the Compressed Air Challenge, up to 30% of all compressed air generated is lost through leaks. This ends up accounting for nearly 10% of your overall energy costs!! To put leaks in perspective, take a look at the graphic below from the Best Practices for Compressed Air Systems handbook.

air leaks cost

Compressed air leaks don’t just waste energy, but they can also contribute to other operating losses. If enough air is lost through leaks, this can also cause a drop in system pressure. This can affect the functionality of other compressed air operated equipment and processes. This pressure drop can affect the efficiency of the equipment causing it to cycle on/off more frequently or to not work properly. This can lead to anything from rejected products to increased running time. With an increase in running time, there’s also the need for more frequent maintenance and unscheduled downtime.

You can perform a compressed air audit in your facility using an EXAIR Model 9061 Ultrasonic Leak Detector. If you’d prefer someone come in and do this for you, there are several companies that offer energy audit services where this will be a focal point of the process.

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EXAIR Ultrasonic Leak Detector

Speaking of maintenance, proper compressor maintenance is also critical to the overall efficiency of the system. Like all industrial equipment, a proper maintenance schedule is required in order to ensure things are operating at peak efficiency. Inadequate compressor maintenance can have a significant impact on energy consumption via lower compressor efficiency. A regular preventative maintenance schedule is required in order to keep things in good shape. The compressor, heat exchanger surfaces, lubricant, lubricant filter, air inlet filter, and dryer all need to be maintained. This can be done yourself or through a reputable compressor dealer. The costs associated with these services are outweighed in the improved reliability and performance of the compressor. A well-maintained system will not cause unexpected shutdowns and will also cost less to operate.

The manner in which you use your compressed air at the point of use should also be evaluated. Inefficient, homemade solutions are thought to be a cheap and quick solution. Unfortunately, the costs to supply these inefficient solutions with compressed air can quickly outweigh the costs of an engineered solution. An engineered compressed air nozzle such as EXAIR’s line of Super Air Nozzles are designed to utilize the coanda effect. Free, ambient air from the environment is entrained into the airflow along with the supplied compressed air. This maximizes the force and flow of the nozzle while keeping compressed air usage to a minimum.

Another method of making your compressed air system more efficient is actually quite simple: regulating the supply pressure. By installing pressure regulators at the point of use for each of your various point of use devices, you can reduce the consumption simply by reducing the pressure. This can’t be done for everything, but I’d be willing to bet that several tasks could be accomplished with the same level of efficiency at a reduced pressure. Most shop air runs at around 80-90 psig, but for general blowoff applications you can often get by operating at a lower pressure. Another simple, but often overlooked, method is to simply shut off the compressed air supply when not in use. If you haven’t yet performed an audit to identify compressed air leaks this is even more of a no-brainer. When operators go to lunch or during breaks, what’s stopping you from just simply turning a valve to shut off the supply of air? It seems simple and minute, but each step goes a long way towards reducing your overall air consumption and ultimately your energy costs.

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

 

Image taken from the Best Practices for Compressed Air Systems Handbook, 2nd Edition

Lost In The Din? Not With An Ultrasonic Leak Detector!

Have you ever found yourself in a noisy environment, trying to hear what someone is saying to you? They could speak up, but sometimes that’s not enough. You might find yourself cupping your hand to your ear…this does two things:

*It blocks a lot of the noise from the environment.  This could also be called “filtering” – more on that in a minute.
*It focuses the sound of the speaker’s voice towards your ear.

IMG_1339
“What? They’re ALL still RIGHT behind me?”

Now, this isn’t a perfect solution, but you’ll likely have much better luck with this in a busy restaurant than, say, at a rock concert. Especially if it’s The Who…those guys are LOUD (vintage loud). If you’re at one of their concerts, whatever your friend has to say can probably wait.

You know what else can be loud?  Industrial workplaces.  Heavy machinery, compressed air leaks, cranes, forklifts, power tools, cranky supervisors/personnel…there are lots of unpleasant but necessary (mostly) sources of sound and noise, right here, where we work.

In the middle of all this, your supervisor might just task you with finding – and eliminating – compressed air leaks…like the person I talked to on the phone this morning.  This is where our Ultrasonic Leak Detector comes in: in places with high noise levels, it could be difficult (if not downright impossible) to hear air leaks.

Most of that noise from the machinery, cranes, etc., is in the “audible” range, which simply means that it’s of a frequency that our ears can pick up.  In a quiet room, you could likely hear an air leak…all but the very smallest ones will make a certain amount of noise…but when a compressed fluid makes its way out of a tortuous path to atmospheric pressure, gets turbulent, and creates an ultrasonic sound it is a frequency that our ears CAN’T pick up on.

Not only does the Ultrasonic Leak Detector pick up on this ultrasonic sound, it can also block (or “filter”) the audible sound out.  It comes with a parabola and a tubular extension so you can hone right in on the area, and then the exact location, of the leak.

If you’d like to find out more about compressed air leak detection, how much you might be able to save by fixing leaks, or how this could make your supervisor a bit less cranky (no guarantees on that last one,) give us a call.

Russ Bowman
Application Engineer
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IMG_1339 courtesy of Rich Hanley  Creative Commons License