## Air & Water DO Mix – Why That’s A Problem for Compressed Air Systems

Wherever you go, humidity – and its effects – are an inescapable fact of life. Low humidity areas (I’m looking at you, American Southwest) make for a “dry heat” in the summer that many prefer to the wet & muggy conditions that areas with higher humidity (like much of the rest of the United States) encounter during the “dog days” of summer.

Regardless of human comfort level issues, all atmospheric air contains water vapor in some finite proportion…in fact, next to nitrogen and oxygen, it makes up a bigger percentage of our air’s makeup than the next eleven trace gases combined:

And, because warmer air is capable of holding higher moisture concentrations (a 20°F rise in temperature doubles the potential for holding moisture), chances are good that it’ll become a bigger problem for your compressed air system in the summertime. So…how BAD of a problem is it? Let’s do some math. Consider a nice, typical summer day in the midwest, when it’s 80°F outside, with a relative humidity of 75% and we’ll use the data from the tables below to calculate how much water collects in the compressed air system:

Let’s assume:

• An industrial air compressor is making compressed air at 100psig, and at a discharge temperature of 100°F.
• The demand on the compressed air system (all the pneumatic loads it services) is 500 SCFM.

Table 3.3 tells us that, at 80°F and 75% RH, the air the compressor is pulling in has 0.1521 gallons per 1,000 cubic feet.

Table 3.4, tells us that, at 100°F and 100psig, the compressor is discharging air with a moisture content of 0.0478 gallons per 1,000 Standard Cubic Feet.

The difference in these two values is the amount of water that will condense in the receiver for every 1,000 SCF that passes through, or 0.1521-0.0478=0.1043 gallons. Since the demand (e.g., the air flow rate out of the receiver) is 500 SCFM, that’s:

500 SCFM X 60 min/hr X 8 hr/shift X 0.1043 gallons/1,000 SCF = 25 gallons of condensate

That’s 25 gallons that has to be drained from the receiver tank over the course of every eight hours, so a properly operating condensate drain is crucial. There are a few types to choose from, and the appropriate one is oftentimes included by the air compressor supplier.

So, you’ve got a condensate drain on your compressor’s receiver, and it’s working properly. Crisis averted, right? Well, not so fast…that 100°F compressed air is very likely going to cool down as it flows through the distribution header. Remember all that moisture that the hot air holds? Assuming the compressed air cools to 70°F in the header (a reasonable assumption in most industrial settings), a bunch of it is going to condense, and make its way to your air tools, cylinders, blow off devices, etc., which can cause a host of problems.

And…I trust you saw this coming…we’re going to calculate just how much condensation we have to worry about. Using table 3.4 again, we see that the header’s air (at 100psig & 70°F) can only hold 0.0182 gallons per 1,000 SCF. So, after cooling down from 100°F (where the air holds 0.0478 gallons per 1,000 SCF) to 70°F, that means 0.0296 gallons per 1,000 SCF will condense. So:

500 SCFM X 60 min/hr X 8 hr/shift X 0.0296 gal/1,000 SCF = 7.1 gallons of condensate

Qualified installers will have sloped the piping away from the compressor, with drip legs strategically placed at low points, so that condensate can drain, collect, and be disposed of…oftentimes via similar devices to the condensate drains you’ll find on the compressor’s main receiver. Good engineering practice, of course, dictates point-of-use filtration – EXAIR Automatic Drain Filter Separators, with 5-micron particulate elements, and centrifugal elements for moisture removal, are also essential to prevent water problems for your compressed air operated products.

EXAIR Corporation remains dedicated to helping you get the most out of your compressed air system. If you have questions, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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## Filtered Compressed Air is the Best Compressed Air: Three Filter Types

When you are using compressed air to Clean, Cool, and or Dry products in production the quality of compressed air you are using is very important. You wouldn’t want to be blowing oil or condensation from your compressed air onto a surface you are trying to dry. Or blowing debris on a surface you are trying to clean.

The most common type of oil removal filter uses a coalescing element.  Oil entrained in pressurized gas flow isn’t as dense as water – so centrifugal elements won’t remove it – and it tends to act like particulate…but very fine particulate – so typical sintered particulate elements won’t remove it.  Coalescing elements, however, are made of a tight fiber mesh.  This not only catches any trace of oil in the air flow, but also much finer particulate than those sintered elements.  EXAIR Oil Removal Filters, like the Model 9027 , provide additional particulate filtration to 0.03 microns.  That’s some pretty clean air.

Dry Particulate Filters: Dry particulate filters are usually employed to remove desiccant particles after an adsorption dryer. They can also be implemented at point of use to remove any corrosion particles from the compressed air. Dry particulate filters operate in a similar manner as a coalescing filter, capturing and retaining particles within the filter media.

Coalescing Filters: Coalescing filters are used for removing water and aerosols. Small droplets are caught in a filter media and merged into larger droplets that are then taken out of the filter. A re-entrainment barrier prevents these droplets from reentering the air. Most of the liquid coalescing filters remove is water and oil. These filters also remove particulates from compressed air, trapping them within the filter media, which can lead to pressure drops if not changed regularly. Coalescing filters remove most contaminants very well.

Adsorption Filters: Vapor removal filters are typically used to remove gaseous lubricants that will go through the coalescing filter. Because they use an adsorption process, vapor removal filters should not be used to capture lubricant aerosols. Aerosols will quickly saturate the filter, rendering it useless in a matter of hours. Sending air through a coalescing filter prior to the vapor removal filter will prevent this damage. The adsorption process uses activated carbon granules, carbon cloth or paper to capture and remove contaminants. Activated charcoal is the most common filter media because it has a large open pore structure; a handful of activated charcoal has the surface area of a football field.

Knowing the needs of your compressed air system can help you chose the right filter. If your air needs a high level of filtration or basic contaminants removed, cleaning your air is an important step in the compressed air process. Check out EXAIRS filter options here!

Jordan Shouse
Application Engineer

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## When Accessories Become Essentials

In my almost three decades of home ownership, I’ve learned a great deal about maintenance in regard to dwelling structures. Among those lessons are:

• The importance of the right tool(s) for the job.
• Having the right materials on hand (I’m looking at you, every plumbing project I’ve ever attempted).
• When it’s a one-person job, a team effort…or a call to the professionals is always in play.

When it comes to EXAIR Intelligent Compressed Air Products, the first and last concerns above are easily addressed. With precious few exceptions, basic hand tools are all that’s required for installation or maintenance, and they’re engineered & manufactured to be “user friendly”. One key aspect of the “user friendliness” is a comprehensive inventory of accessories.

Some of these accessories are unique to a particular Product Line:

• Air Knife Plumbing Kits are great, especially for the longer Super Air Knives that need to be plumbed to multiple ports along their length. These consist of air hose and brass fittings (for Aluminum Super Air Knives) or Stainless Steel tubing and fittings (for the Stainless Steel models) that connect in to those multiple ports, allowing for infeed to just one (for Super Air Knives up to 54″ long) or two (for lengths up to 108″) 1/2 NPT fittings. These can actually be used on our Super Ion Air Knives as well.
• Universal Air Knife Mounting Systems provide for ease of installation, and precise positioning of our Aluminum or Stainless Steel Super, Standard, or Full Flow Air Knives.
• Coupling Bracket Kits can join Super Air Knives together for a continuous, uninterrupted curtain of air flow in any length that you need. They can also be used if you don’t always need air flow along the entire length of a Super Air Knife assembly. I had the pleasure of assisting a user once who had needed to blow off parts on a hanging conveyor. Some parts were a little under 2ft long; others were about 4ft long. They used the Model 110900 Coupling Bracket Kit to join two Model 110024 24″ Aluminum Super Air Knives together, plumbed them separately, and turned both of them on for the long parts, and just the ‘top’ one for the shorter parts.

Other accessories can be used for a variety of products:

• Stay Set Hoses (with or without Magnetic Bases) make up instant Blowoff Systems when used with our engineered Air Nozzles. They come in lengths from 6″ to 36″, and can bent by hand to “stay set” (as advertised) to hold their position. They can repositioned, as needed. They’re also popular for use with our 3/4″ and 1-1/4″ Super & Adjustable Air Amplifiers, and can even be used with 3″ Air Knives.
• Conveyance Hose is a great way to connect point A to point B in a Line Vac Air Operated Conveyor system. Bulk material conveyance really doesn’t get much easier than Line Vac + Hose = Instant Conveyor System (just add compressed air). It can also be used with our Air Amplifiers to duct or route the air flow on the inlet, or the outlet to, or from, one area to another.
• Mounting Brackets are available for a number of our products:
• Atomizing Spray Nozzles
• Line Vacs
• Filters and Regulators
• Cabinet Cooler System Thermostats
• Vacuum Cups are often used with our E-Vac Vacuum Generators for pick-and-place material handling applications. We stock fittings and push-in tubing as well, to complete the package. Those fittings and tubing can also be used for the liquid supply to our Atomizing Spray Nozzles (depending on what you’re spraying, you might want to verify chemical compatibility first; call me if that’s a concern).

Other EXAIR Compressed Air Product Accessories can be used with products that aren’t even ours, or, in conjunction with your compressed air system design for increased efficiency or flexibility:

• Model 9500-60 60 Gallon Receiver Tanks can be installed near points of high air flow demand to prevent or limit fluctuations in supply throughout the system.
• Compressed Air Hoses can be made to length, and a variety of Fittings (Hex or Close Nipples, Couplers, Reducers, Tees, Elbows, Crosses, and Bulkhead Fittings) are on the shelf in popular sizes.
• Our 5 Micron water/dirt Filter Separators are a standard when needing clean, condensate free air to blow through and end-use product.
• Pressure Regulators are an important factor to minimize compressed air consumption. EXAIR always recommends operating our products at the minimum pressure necessary for a successful application. For example, if using a Super Air Knife to remove dust and light debris, this could be achieved at 20 PSIG, a Pressure Regulator will provide that adjustability and keep the air consumption much lower than if it were operated at 80-100 PSIG.
• Swivel Fittings, typically used with compressed air nozzles, provide the precision adjustability to focus in on the exact area you need to treat.

If you have any questions about how the above accessories can aid with your application, please relay on our expert team for answers and solutions. Having the right materials and accessories on-hand can simplify installation, enhance performance, save compressed air, and more!

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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## Top Factors for Air Compressor & System Maintenance

Performing regular maintenance on your compressor system helps to keep everything operating in peak condition and ensures you’re not wasting unnecessary energy. Just as you perform regular routine maintenance on your vehicles, a compressed air system also needs a little TLC to keep things running smoothly. Neglected maintenance items can lead to increased energy costs, high operating temperatures, and coolant carryover. Much of these issues can be eliminated simply by performing routine maintenance on the components of the system.

According to the Best Practices for Compressed Air Systems by the Compressed Air Challenge (1), components within the system that need maintained include: the compressor, heat exchanger surfaces, lubricant, lubricant filter, air inlet filter, motors, belts, and air/oil separators.

The compressor and all surfaces of the heat exchanger need to be kept clean and free of contaminants. When these components are dirty, compressor efficiency is greatly reduced. Any fans and water pumps should also be regularly inspected to ensure that they’re functioning properly. The air inlet filter and piping should also be cleaned. The quality of the air in the facility will impact the frequency, refer to the manufacturer’s specifications for ideal intervals for performing scheduled maintenance.

The lubricant and lubricant filter must also be changed per manufacturer’s specifications. Old coolant can become corrosive, impacting useful life and damaging other components while reducing efficiency. While synthetic lubricants are available that have an extended life compared to standard coolants, this does not extend the life of the lubricant filter itself.

Belts should be routinely checked for tension (every 400 hours is reasonable) to alleviate bearing wear. Belts will stretch and wear under normal operation and must be adjusted periodically. It’s a good practice to keep some spares on hand in the event of a failure.

End use filters, regulators, and lubricators should also be periodically inspected and filter elements replaced as needed. If left unchecked, a clogged filter will increase pressure drop. This can cause both a reduction of pressure at the point of use or an increase in the pressure supplied by the compressor, leading to increased energy costs.

Another often overlooked maintenance item is leak detection and repair. Leaks contribute to unnecessary air usage, pressure drop, and increased energy costs. EXAIR offers an Ultrasonic Leak Detector that can be used to identify the leaks in your system and allow you to make the necessary repairs.

In order to keep your system running in peak condition, regular maintenance is critical. By paying close attention to the manufacture’s recommendations, and implementing a regular maintenance schedule, you can ensure you’re getting the most out of your system components.

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