Compressed Air System Maintenance

Air Compressor and Storage Tanks

Compressed air is the life blood of a manufacturing plant, and the air compressor would be considered the heart. To keep things “fit”, it is important to check all areas and to optimize your system to keep your plant running safely and efficiently. You do not have to be a doctor to do these “operations”. If your compressor fails, the entire facility will stop working. In this blog, I will cover some simple preventative maintenance that can really help you.

As margins get tighter and cost of manufacturing climbs, industries are looking into other areas to be more economical. A big focus today is the compressed air system. Compressed air is considered to be a “forth” utility behind gas, water, and electricity, and it is a necessary to run your pneumatic systems. But it is the least efficient of the utilities. So, it is very important to use this utility as practical as possible and to use a PM program to keep it going.

If we start at the beginning of your compressed air system, this would jump us to the air compressor. This is the machine that uses an electric or gas motor to spin a crank. It compresses the ambient air into a small volume to generate stored energy to be used by your pneumatic systems. Because the air compressor is complex and intricate, I would recommend a trained service personnel to do the maintenance. But, if your staff is familiar with air compressors, I wrote a blog to help look at certain parts periodically. You can read it here: “6 Basic Steps for Good Air Compressor Maintenance (And When to Do Them)”.

The next part after the air compressor is to look at the aftercoolers, compressed air dryers, receiver tanks, filters, and condensate drains. Some facilities may only have some of these items.

The aftercoolers are designed to cool the exit air from your air compressor. It uses a fan to blow ambient air across coils to lower the compressed air temperature. It is easy to check the fan to verify that it is spinning and to keep the coils clean from debris.

The compressed air dryers can range in size and type. For the refrigerant type air dryers, you should periodically check the freon compressor with ohm and amp readings, the condensers for cleaning, and the super heat temperature as well. For desiccant type air dryers, you will need to check the operation of the valves. Valves are used to regenerate one side of the desiccant bed. The valves can fail and stick either open or closed. In either way, if the desiccant cannot regenerate, then it will allow moisture to go down stream and eventually destroy the desiccant beads.

The receiver tanks have safety relief valves that will need to be checked to make sure that they are not leaking. If they are, they should be changed.

As for the filters, they collect contamination from the compressed air stream. This will include liquid water, oil, and dirt. A pressure drop will start to increase with the contaminants, which will reduce the potential energy. If they do not have pressure drop indicators, you should have two points of references for pressure readings. You should change the filter elements when the pressure drop reaches 10 PSID (0.7 bar) or after 1 year.

With all these items above, water is created. There should be condensate drains to discard the water. The most efficient types of condensate drains are the zero loss drains. Most condensate drains will have a test button to be pressed to verify that they open. If they do not open, they should be replaced or fixed. Do not place a valve on them and partially open for draining. For float type drains, they will have a pin inside that can be pressed to open. You can verify that all the liquid has been expelled.

The distribution system are the pipes and tubes that run compressed air from the supply side to the demand side of your pneumatic system. One of the largest problems affecting the distribution system are leaks. That quiet little hissing sound from the pipe lines is costing your company much money. A study was conducted by a university to determine the percentage of air leaks in a typical manufacturing plant. In a poorly maintained system, they found on average of 30% of the compressor capacity is lost through air leaks.

To put a dollar value on it, a leak that you cannot physically hear can cost you as much as $130/year. That is just for one inaudible leak in hundreds of feet of compressed air lines. Unlike a hydraulic system, compressed air is clean; so, leaks will not appear at the source. So, you have to find them by some other means.

Digital Flowmeter

 

EXAIR Ultrasonic Leak Detector

Most leaks occur where you have threaded fittings, connections, hoses, and pneumatic components like valves, regulators, and drains. EXAIR has two products in our Optimization product line that are designed to help find leaks in your compressed air system.

The Ultrasonic Leak Detectors can find air leaks, and the Digital Flowmeters can monitor your system for loss of air. When an air leaks occur, it emits an ultrasonic noise caused by turbulence. These ultrasonic noises can be at a frequency above audible hearing for human. The EXAIR Ultrasonic Leak Detector can pick up these high frequencies to make inaudible leaks audible.

With the Digital Flowmeters, you can continuously check your system for waste and record it with a USB Datalogger.  Air leaks can occur at any time within any section of your pneumatic system.  With a Digital Flowmeter, you can also isolate an area to watch for any flow readings; telling you that the air is leaking in that section.  With both products included in your leak-preventative program, you will be able to reduce your waste and optimize your compressed air system.

Family of Nozzles

At the point-of-use areas, this is the easiest target area for compressed air maintenance. If you are using open tubes or drilled pipes for blowing, they are loud, inefficient, and unsafe. They can be easily change to an engineered blow-off product from EXAIR which are very efficient and OSHA safe. EXAIR offers a range of Super Air Nozzles and Super Air Knives to simply replace the current blow-off devices that overuse compressed air. If we go back to the beginning of your system, the air compressor is a mechanical device which will have a MTBF, or Mean Time Between Failures. The hour meter on your air compressor is like a life monitor. By using less compressed air, your air compressor will extend that time in MTBF.

Keeping your compressed air system running optimally is very important for a business to run. With a simple maintenance program, it can help you with your pneumatic operations and energy savings. Like stated above, your compressed air system is the life blood of your company, and you do not need a PhD to keep it well maintained. Just follow the target areas above. If you would like to discuss further about the health of your compressed air system, you can contact an Application Engineer at EXAIR. We will be happy to help “diagnose” a solution.

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

Finding & Fixing Leaks: The Benefits of Creating a Leak Detection Program

Leaks in a compressed air system can be a substantial source of wasted energy. A facility that hasn’t maintained their compressed air system will likely have a leak rate around 20-30% of the total air production.  But with a leak detection plan you can reduce air leaks to less than 10% of the compressor output.

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Along with the energy waste, leaks will contribute to higher operating cost.  Leaks cause a drop in system pressure, which can make air tools operate poorly, harming production cost and time. In addition, by forcing the equipment to cycle more often, leaks shorten the life of almost all system equipment, including the compressor. Increased running time can also lead to added maintenance and increased downtime. Finally, leaks can lead to adding unnecessary compressor volume.

Since air leaks are almost impossible to see, other methods must be used to locate them. The best way to detect leaks is to use an ultrasonic acoustic detector, Like EXAIR Ultrasonic Leak Detector (ULD). This unit can recognize the high frequency hissing sounds associated with air leaks. A person using the ULD only needs to point it in the direction of the suspected leak. When a leak is present, an audible tone can be heard with the use of the head phones, and the LED display will light.  Testing various unions, pipes, valves and fittings of a complete system can be done quickly and effectively at distances up to 20’ away!

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The advantages of ultrasonic leak detection include flexibility, speed, ease of use, the ability to test the system while machines are running, and the ability to find a wide variety of leaks. They involve very little training, operators often become competent after 10 minutes of training.

Due to the nature of ultrasound, it is directional in transmission. For this reason, the signal is loudest at its source. By scanning around a test area, it is possible to very quickly target in on a leak site and pin point its exact location. For this reason, ultrasonic leak detection is not only fast, it is also very accurate.

An active leak prevention program will embrace the following components: identification, tracking, repair, verification, and employee participation. All facilities with a compressed air system should establish an aggressive leak reduction program. A team involving managerial representatives from production should be formed to carry out this program.

A leak prevention program should be part of an overall program intended to improve the performance of compressed air systems. Once the leaks are found and repaired, the system should be started from the beginning until all leaks are addressed.

A good compressed air system leak repair program is very important in maintaining the efficiency, reliability, stability and cost effectiveness of any compressed air system.

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“First a Plant Engineer or Maintenance Supervisor must realize that leak repair is a journey, not a destination. An ongoing compressed air leak monitoring and repair program should be in place in any plant that has a compressed air system.” Explains Paul Shaw, a General Manager for Scales Industrial Technologies’ Air Compressor Division, and an Advanced CAC Instructor, “Leak identification and remediation with a high quality repair can lead to substantial energy savings that typically has a very rapid payback, usually a year or less. In the hundreds of leak audits and repairs that we have done we’ve found that the quality of the repair is critical to ensuring the customer receive the most value for his investment and that the leak remains repaired for as long as possible. From there, constantly monitoring for compressed air leaks and repairing them as they occur can help the plant continue to reap the energy benefits.”

Above is an excerpt from “Best Practices for Compressed Air Systems”, Appendix 4.E.1.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer

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