Tag: air filter

Compressed Air Pipe

Intelligent Compressed Air: System Equipment

Published on by Russ BowmanLeave a comment

At the end of Naval Nuclear Power School, students who’ve just spent two years learning how to boil water must pass a comprehensive examination board before they’re released into the fleet as real live “Navy Nucs.” One popular question at these boards (in 1987 anyway) was to describe, in detail, the path a drop of seawater takes to become reactor coolant (a warship at sea must be self-reliant, and that includes making our own pure water.) A correct answer would prove the student’s knowledge of various piping systems, the steam distilling and water purification processes, reactor coolant chemistry maintenance, and, if you were lucky, a deep dive into the Six Factor Formula which mathematically defines the six events* that affect the probability of neutron multiplication, and hence, the sustainability of nuclear fission in the reactor core:

*Two of these six events relate to the thermalization of neutrons by the coolant. That’s why it’s considered to be a valid part of the ‘seawater-to-reactor-coolant’ question.
The block on the left represents a cubic foot of air at atmospheric pressure. The one on the right represents how much space the first one takes up when compressed to 100psig.

In that same vein, for today’s EXAIR blog, I thought I’d trace a Standard Cubic Foot (SCF) of air from the compressor room, through a typical industrial compressed air system, to its point of use. First, let’s define what that is: Imagine a cubic foot of air in front of you. If the atmospheric pressure is 14.5psia (average for sea level elevation), the ambient temperature is 68°F, and relative humidity is 0%, then that’s one Standard Cubic Foot of air. Now, let’s say this air is in an ideal compressor room – ‘ideal’ meaning those atmospheric conditions apply – and follow its path to an EXAIR Super Air Knife:

  • Filter, Part 1 (intake): When the air compressor draws our SCF in, it passes through filtration media to remove impurities like dust, oil, and moisture. It’s important to remember that this filter is there to PROTECT THE COMPRESSOR from those contaminants, not to provide any measure of cleanliness to the compressed air itself.
  • Compression: This is where our SCF gets compressed by reciprocal or rotating elements imparting energy to it, and it now occupies considerably less space than it did in the atmosphere. This also raises the temperature. When all the molecules that comprise our SCF get closer together, they run into each other more often, and that increased friction makes them hotter. Which can be bad, unless we do something about it.
  • After cooler: Hot compressed air can cause unsafe surface temperatures and can damage gaskets, seals, or other components in the downstream system. Cooling our SCF down is the first thing we want to do after compressing it.
  • Filter, Part 2 (discharge): While the Intake Filter takes care of impurities that could have damaged the compressor, the compressor itself can add some back into our SCF – like oil, wear particulate from meshing gears or seals on moving parts, etc. You’ll want to remove those as well, before letting them go any further in the system. Contaminants like that can really do a number on the operation and effectiveness of some types of dryers.
  • Dryer: While the intake filter removes some finite amount of moisture from our SCF before compression, the compression cycle increases the moisture concentration of it. Dryers come in different types and configurations, each with their own pros & cons, and certain types are more suitable for certain situations. Here’s a link to a blog on the subject by Jordan Shouse that’s both informative and entertaining!
  • Primary Storage: Once our SCF gets cooled, cleaned, and dried, it can take a little break if it’s not needed right away, in a receiver tank. Such a tank, like EXAIR’s Model 9500-60 60 Gallon Receiver Tank (right), near the compressor discharge, serves several purposes:
    • It maintains header pressure during any load transients that happen too quickly for the compressor to keep up in real time.
    • It provides further moisture removal, as any water that condenses in this receiver can be drained from a valve on the bottom.
    • It also allows the compressed air to cool further.
  • Distribution Header Piping: This is the “highway,” if you will, that our SCF travels to where it’ll be used. It’s not alone, either – there are sometimes hundreds, if not thousands, of other SCF’s passing through every minute. And if it’s not appropriately sized, there’ll be problems akin to traffic jams on crowded roads. The appropriate size and layout of the header piping will be determined by a number of factors – here’s a link to a blog with more details on that.
  • Airdrops: These are the branches from the distribution header that lead to the various points of use in the facility. Our SCF will take whichever one it gets directed to…in this case, the aforementioned EXAIR Super Air Knife. The proper size of the drop piping or hose will be determined by the compressed air consumption of the load(s) serviced by the drop, and its length from the header. In the case of our EXAIR Super Air Knife that our SCF is heading towards, the recommended in feed pipe sizes are listed in the Installation/Maintenance Guide:
The longer the drop length, the larger the diameter needs to be to compensate for line loss due to friction.
  • Filter, Part 3 (point of use): Good engineering practice calls for point-of-use filtration. Our SCF has already been through two filters, I know, but it’s also potentially picked up some more contamination along the way. Rust from the inside walls of iron pipes is the most common culprit. The EXAIR Super Air Knife that our SCF is heading towards needs its supply to be filtered for particulate to a level of 10 microns or less. EXAIR Automatic Drain Filter Separators have 5-micron particulate elements, and centrifugal elements that ‘spin’ out any remaining moisture. Depending on the needs of the application, we also have Oil Removal Filters with coalescing elements for oil/oil vapor. They also provide additional particulate filtration to 0.03 microns.
  • Regulator: It’s taken a good deal of effort and expense to get our SCF to this point, so it only makes sense to use it as efficiently as possible. A Pressure Regulator allows us to precisely ‘dial in’ the supply pressure so that we don’t use it (or any of the other SCF’s that it’s traveling with) any more than needed.
EXAIR Automatic Drain Filter Separators (left) can be directly coupled to Oil Removal Filters (center) and Pressure Regulators (right) for a compact installation, free from threaded connections.
EXAIR’s award-winning EFC Electronic Flow Control is a ‘plug and play’ system that can save you THOUSANDS of dollars in compressed air costs.
  • Shutoff valve: Years ago, I talked to an engineer at a company that was using one of our Super Air Knives to blow off parts that were passed in front of it by a robot. The robot’s arm turned & rotated the part in the air curtain to ensure it got completely blown off. This only took a couple of seconds, as the operators had ‘tweaked’ the arm movement to do it as quickly as possible. However, there were about 15 seconds between parts…and the Super Air Knife WAS BLOWING THAT WHOLE TIME. Since they’d already told me how great their automation techs were at programming the robot, I suggested that they go one more step and install a Solenoid Valve in the supply line to the Super Air Knife and use the robot’s logic to open it right before the robot got there, and close it right after the robot left. Step Four of our Six Steps To Optimizing Your Compressed Air System is to “turn off the compressed air when it’s not in use,” and by doing so, they reduced the compressed air consumption of this one Super Air Knife by about 80%. THAT’S optimized. If you don’t have existing logic to do this, our EFC Electronic Flow Control will do it for you.
  • The Super Air Knife: At long last, our SCF is ready to fulfill its purpose, and the Super Air Knife will help it do so in the most efficient way possible. It uses that SCF of air, along with all the others that pass through, to entrain a WHOLE BUNCH of SCF’s from the surrounding environment. The amplification ratio for EXAIR Super Air Knives is 40:1, making them the most efficient compressed air-blowing products on the market.
EXAIR Super Air Knives come in lengths from 3″ to 108″, and are available from stock in aluminum, 303SS, 316SS, or PVDF.

It’s been a LONG time since I’ve used the Six Factor Formula for the neutron life cycle in nuclear fission (and honestly, I haven’t missed it all that much), but every day, I use formulas and figures related to:

Just to name a few. If you’d like to “math something out,” (just not the Six Factor Formula, please), give me a call.

Russ Bowman, CCASS

Application Engineer
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The Importance Of Preventative Maintenance

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The first brand-new car I ever bought was a 1995 Ford Escort wagon. I was playing in a band pretty much every weekend (and the occasional weeknight), and my digital piano case fit perfectly in the back – I took it with me to make sure when I went to test drive it. Over eleven years, I put just shy of 200,000 miles on it, and, aside from gas, oil, and tires, had a little under $1,000 in repair costs.

There used to a legendary warning about not buying a car made on a Monday (since the auto workers were presumably recovering from the weekend) or a Friday (since they were equally presumably distracted by getting ready for the weekend). Some folks only buy a particular make of automobile (or shun another) because that’s the make their favorite race car driver (or least favorite) drives. I don’t know what day of the week that Escort was made, and I couldn’t tell you which race car drivers are loyal to the Ford Motor Company, but I CAN tell you that I followed the manufacturer’s recommended maintenance schedule to a “T”. And I’m pretty sure that had a LOT more to do with that little red wagon’s longevity than a bunch of auto workers’ attention to detail (or lack thereof) or who’s popular on the NASCAR circuit.

The same is true for many components that make up your compressed air system. You’re going to want to change the lubricating oil in your compressor on a regular basis (as recommended by the manufacturer) for the exact same reasons you change the oil in your car’s engine. You need to replace particulate elements in compressed air filters, same as you need to periodically replace your car’s air filter.

For point-of-use devices – like most EXAIR compressed air products – preventative maintenance largely comes down to replacing those particulate elements in your filters. Products like our Air Knives, Air Wipes, Air Amplifiers, E-Vac Vacuum Generators, Reversible Drum Vacs, and Vortex Tubes all have relatively small passages that the air has to flow through, so it’s critical to their performance to supply them with clean air. In fact, if you DO supply these products with clean air, they’ll run darn near indefinitely, maintenance free. That’s why all of our product Kits include a Filter Separator with a 5 micron particulate element, and a centrifugal element for moisture removal.

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

One question we get on a pretty regular basis is, how often do you have to change the particulate element in our Filter Separators. Good engineering practice calls for replacing that element when the differential pressure across the filter reaches 5psi. Now, you can measure the pressure on either side of the Filter Separator and change the element when the outlet pressure drops 5psi from the inlet. If you can shut down long enough to do so, that’s an efficient way to do it – that ensures you get the most ‘bang for your buck’ from that element.

Of course, those elements don’t cost all that much – but shutting down a production line, for even the few minutes it takes to replace an element, can get VERY costly. Facilities that run 24/7 will usually plan some downtime for periodic maintenance on SOMETHING…and they’ll just replace their Filter Separator’s particulate elements during those downtimes.

If you’ve got questions about getting the most out of our products – and, by extension, your compressed air system – give me a call.

Russ Bowman, CCASS

Application Engineer
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The Importance Of Preventative Maintenance

Published on by Russ BowmanLeave a comment

The first new car I ever bought was a 1995 Ford Escort Wagon. It got GREAT gas mileage (which was important for my 25 mile one-way commute to the day job), and had ample room to haul my keyboards & amplifier rig (which was just as important to my side hustle as a potential rock star). Since it only had four miles on the odometer – and, it was the first purchase I ever financed over a period of YEARS, I decided to follow the owner’s manual’s maintenance schedule religiously. And it paid off: I got eleven years and just shy of 200,000 miles out of one of the least expensive cars ever made. It was actually still running like a top when I sold it to “upgrade” to a minivan, which suited my needs at the time for a vehicle that fitted the car seats for our little boys (who are now a U.S. Marine and a hippie college student, respectively). I actually followed the maintenance schedule for that minivan too, and got 14 years & almost 180,000 miles out of it, without a major breakdown.

Whether you call it “preventive”, “preventative”, “scheduled”, or “planned” maintenance, there’s an old adage that applies in any case:

“If you don’t plan maintenance, it’ll plan itself without regard to your schedule.”

While following the proverbial “owner’s manual’s maintenance schedule” doesn’t guarantee against catastrophic failures, it’s awfully good insurance against them. For your privately owned vehicles, I encourage you to follow the owner’s guide as best you can. For your compressed air system – from the compressor to the devices it provided compressed to (and everything in between) – there’s likely similar documentation to follow, and for good reason. Consider:

  • Air compressor maintenance. Failure to properly maintain a compressor can increase energy consumption by not keeping it operating as efficiently as possible. For example, just like not periodically replacing your car engine’s air filter will impact your gas mileage, failure to do the same for your compressor’s intake air filter will impact its production of compressed air.
  • Air leaks are costly. Not only do they waste the money you spent on running the compressor (a leak that’s equivalent to a 1/16″ diameter hole costs you over $700.00 annually – let me know if you want to do the math on that), your system pressure takes a hit too. Pressure drop caused by those leaks (plural because there’s rarely just one) can create what’s known as “false demand”, which costs you money as well: every 2psi increase in compressor discharge pressure makes for a 1% increase in power consumption. So, it’s really important to stay on top of them. Regularly scheduled surveys with an instrument like EXAIR’s Model 9207 Ultrasonic Leak Detector allows you to quickly find – and then fix – those leaks.
EXAIR Model 9207 Ultrasonic Leak Detector comes with everything you need to find out if you have a leak (with the parabolic disc, lower right) and then zero in on its exact location (with the tubular extension, bottom).
  • Filters, part 1: I already mentioned the compressor intake filter above, but the rest of the filters in the system need attention from time to time as well. Filter manufacturers typically call for replacing the element in a filter when pressure drop reaches a certain point. I’ve seen published values of 2-5psi for that. Of course, that may not occur at a convenient time to shut down everything downstream of that filter, so lots of folks replace those elements as part of planned maintenance evolutions that require depressurization of that particular part of the system anyway. Dirty filters mean you have to increase their inlet pressure to maintain the same outlet pressure you had when they were clean – and the same 1% increase in power consumption for a 2psi pressure increase applies here too.
  • Filters, part 2: most compressed air operated products have small passages that the air has to flow through, and without filtration, those can get clogged with dirt that the intake filter doesn’t catch, solid particulate from compressor ‘wear & tear’, and rust from header pipe corrosion, just to name the “usual suspects”. An argument could be made that installation & upkeep of properly rated Filter Separators at the point of use of these devices is part of those devices’ planned maintenance. In any case, it’s akin to the awfully good insurance against catastrophic failures I mentioned earlier.
Good engineering practice calls for point of use filtration and moisture removal, such as that provided by EXAIR Filter Separators.

Again, many of the components that make up a typical industrial compressed air system will have a manufacturer’s recommended maintenance schedule, but if they don’t, how can you properly plan for it? Monitoring of certain system parameters can be a valuable tool for determining how often some planned maintenance should be performed:

  • Power consumption of the compressor. The benefit of measuring & logging this on a regular basis is, if you see sudden changes, you can start looking for what’s causing them. Maybe a bearing or belt is wearing out, some leaks have popped up, or a filter’s clogged. In any case, it’s an indication that SOMETHING needs attention. Large industrial compressors might even have power monitoring in their control scheme. If not, there ARE other parameters you can measure…like:
  • Pressure and flow. EXAIR’s Pressure Sensing Digital Flowmeters make monitoring these parameters quick and easy. Managing the readings can be done with our USB Data Logger, or you can get it on your computer, via a Zigbee Mesh Gateway, with our Wireless Models.
EXAIR Digital Flowmeters are made for iron, copper, or aluminum compressed air pipe in sizes from 1/2″ to 8″ diameters. Options include Pressure Sensing, Wireless Output, USB Data Logger, Hot Tap, and Metric display.

At EXAIR, we’re committed to helping you get the most out of your compressed air system. If you’d like our help with that, give me a call.

Russ Bowman, CCASS

Application Engineer
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Featured image courtesy of Compressor1 – creative commons license

Why – And Where – Do You Need Filtration In Your Compressed Air System?

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Good engineering practice, and proper system design, call for filters at various points in a compressed air system. I’m going to go through these along the path that compressed air follows, from being drawn from atmospheric pressure in to the compressor, to being returned to atmospheric pressure at its point of use.

Any air compressor is going to have an intake filter. The small “pancake” compressor in my garage has a little disc looking thing with a screen whose mesh is about the same as my house’s window screens. Larger industrial air compressors have cartridge-type filters that impart a spiral motion to the incoming air. That motion actually removes most of the incoming particulate, while the rest gets caught in the pleats of the fiber element. The main purpose for an intake filter is to protect the compressor’s internal components. Solid particulates can really do a number on the high speed, close tolerance moving parts inside a compressor, in a hurry.

All the other filters you might find are there to ensure proper operation of the rest of your compressed air system:

  • Distribution. No intake filter is going to be 100% efficient, nor will it remove especially fine particulate that doesn’t present a real risk of damage or wear to the compressor. Intake filters also will not remove oil (or oil vapor) and water (or water vapor). The compressor itself can actually add contaminants to the compressed air, in the form of wear particles (remember those close tolerance moving parts I mentioned above?) and oil carryover. All of these contaminants will, however, be detrimental to the pipe & fittings that takes the newly compressed air to where it’s used. They can cause a buildup on the inner walls of the piping that inhibits flow. Water causes the pipe to start rusting from the inside out. When that rust scale breaks loose, it can clog, foul, or damage valves, fittings, and other control devices in the distribution header. Ideally, you’ll use filtration with a particulate element, a centrifugal element for water, and a coalescing element for oil/oil vapor (if needed…this isn’t a concern for oil-free compressors, for example).
  • Distribution, part 2. If your facility is large enough, you may need filtration at strategic locations…perhaps one for the air going to the machine shop, another for an area with machinery equipped with pneumatic cylinders, another for an assembly area where pneumatic tools are used, etc. The type(s) of filter(s) you use at those points will be determined by what the air is used for. If you know you have oil carryover from your compressor, you probably want a coalescing filter on the line to Safety Air Guns that blow off parts before painting. You don’t need them on lines going to your pneumatic tools, though…that carryover will likely help supplement the point-of-use lubricators that they use.
  • Point-of-use. Good engineering practice calls for a final stage of filtration, located as close as practical to the air operated device(s). EXAIR includes a Filter Separator with a 5 micron particulate element and a centrifugal element for water with all of our product Kits. Oil Removal Filters are also available for oil/oil vapor. They also provide additional particulate filtration to 0.03 microns.
EXAIR offers a variety of Filter Separators (left), Oil Removal Filters (middle), and Pressure Regulators (right) that are suitable for a wide range of point-of-use compressed air applications. Contact an Application Engineer for more details.

At EXAIR, we’re here to make sure you get the most out of your compressed air system. If you’d like to find out more about filtration…or any other aspect of air treatment (drying, regulating, cooling, etc.)…give me a call.

Russ Bowman, CCASS

Application Engineer
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