Once again, the celebrations and giving around the EXAIR office become common. It is a joy to take a moment away from selling air nozzles together and simply enjoy each other’s company. Fortunately for us, we are good at it!
We will also be enjoying some time away from the office, as we will be closed Dec 23, 24, and 25. While we celebrate the New Year, we will be closed Dec 30, 31 and Jan 1.
We hope that all of you, too, get some time away from your jobs to spend with friends and family. Take advantage of any time off whether is is to relax, have fun, read, nap, volunteer, or whatever YOU choose. EXAIR hopes your holidays are what you want them to be.
When it comes to generating compressed air there are many types of compressors to utilize within a facility. One of those types is a dual acting reciprocating compressor. This is a type of positive displacement compressor that takes advantage of a piston style action and actually compresses air on both directions of the stroke. Below you can see a video from a company that showcases how a dual acting compressor works and gives a good representation of how it is compressing the air on both directions of travel.
The reciprocating type of air compressor uses a motor that turns a crank which pushes a piston inside a cylinder; like the engine in your car. In a basic cycle, an intake valve opens to allow the ambient air into the cylinder, the gas gets trapped, and once it is compressed by the piston, the exhaust valve opens to discharge the compressed volume into a tank. This method of compression happens for both the single and double acting reciprocating compressors.
With a single acting compressor, the air is compressed only on the up-stroke of the piston inside the cylinder. The double acting compressor compresses the air on both the up-stroke and the down-stroke of the piston, doubling the capacity of a given cylinder size. This “double” compression cycle is what makes this type of air compressor very efficient. A single acting compressor will have an operating efficiency between 100 cfm / 23 kW of air while the double acting compressor has an operating efficiency between 100 cfm 15.5 kW . Therefore, electricity cost is less with a double-acting reciprocating air compressor to make the same amount of compressed air.
These compressors are ruggedly designed to be driven 100% of the time and to essentially be a Clydesdale of compressors. They are commonly used with applications or systems requiring higher pressures and come in lubricated or non-lubricated models.
If you would like to discuss air compressors or how to efficiently utilize the air that your system is producing so that you aren’t giving your compressor an artificial load that isn’t needed, contact us.
With 142 distinct models in stock, the Atomizing Spray Nozzles are easily EXAIR Corporation’s most diverse product line. If you need a reliable method of creating a fine mist of liquid flow with a flow rate as high as 303 gallons per hour (or as low as 0.1 gallons per hour,) with a spray pattern as large as 13 feet (or as small as 2-1/2 inches) in diameter, look no further – we have a spray nozzle for you, on the shelf and ready to go.
Siphon Fed models are the subject of today’s blog – they don’t require that the liquid be under pressure; you can feed them from the vessel the liquid comes in from a siphon height of up to 36 inches, or, for higher flows, from a gravity height of as low as 6 inches.
All Atomizing Spray Nozzles are available with EXAIR’s patented No-Drip option, which positively shuts off liquid flow when the compressed air supply is shut off. One benefit of this is realized in coating applications, where an errant droplet of liquid would mar an otherwise smooth, even coating. Operationally, though, it also means you can precisely turn the liquid flow on & off, in short, quick bursts, up to 180 times a second.
By far, the simplest way to do this is with a valve installed in the air supply line to the Atomizing Spray Nozzle. A manual 1/4 turn ball valve works fine if you want the operator to control it. Solenoid valves are often used to automate the process, and if you’ve got something to open & close the valve, you’re all set. For example, if you want to spray coolant onto a cutting tool, just wire the solenoid valve into the on-off switch of the machine, like in the example shown to the right.
Alternately, our EFC Electronic Flow Control System provides a ready-to-go solution. It comes pre-wired; all you have to do is plumb the valve into the air supply line and plug it in to a 120VAC grounded wall outlet. When the photoelectric sensor “sees” the part you want to spray, it opens the valve. When the part passes, it shuts the valve. Easy as that.
Sound levels and ROI don’t immediately link together in a quick thought. Unless you are me and things seem to link up that don’t always go together, like peanut butter and a cheese burger. (Trust me, just try it, or if you are near West Lafayette, Indiana just go try the Purvis Burger across the street from Purdue University.) The truth behind tying sound levels being reduced and ROI together is actually pretty simple.
For this example, I am going to stay fairly high level as we could get into some pretty deep measurements of what exactly could be a cost savings. If we reduce the sound level being generated by point of use compressed air products that is easiest to do by implementing engineered blow off products as well as reducing the operating pressure. Let’s use this example: A 1/4″ copper tube that is being used as a blow off will give off a noise level of over 100 dBA from 3′ away. The table below shows that at an 80 psig inlet pressure the same tube will also consume 33 SCFM of compressed air.
By installing a model 1100 1/4″ FNPT Super Air Nozzle on the end of this copper tube, we reduce the noise level generated by the blow off to 74 dBA. This measurement is at the same 80 psig inlet pressure and from 3′ away, which is well below the OSHA standard for allowable noise level exposure. This also gives a broader more defined pattern to the air stream which may permit a reduction in compressed air pressure.
The other factor this changes is that the air consumption is reduced by 19 SCFM of compressed air which then results in energy savings. This ultimately ends in a simple ROI equation where we are simply using the compressed air reduction as the only variable for the return.
By reducing the air consumption of a process that operates 24/7, 250 days a year that equates to a savings of 6,840,000 SCFM per year and that equates to $1,710.00 USD. This does not account for any reduction in paying for hearing protection that may no longer be needed, or increase in production because the application functions better.
So you see, reducing noise levels in a facility can easily amount to a sizable cost savings in energy going towards compressed air consumption. If you would like to walk through any potential applications, please contact us.
When it comes to engineered compressed products, the number one cause of less-than-optimal performance is improper supply line sizing. This can mean one of two things:
The hose, pipe, or tubing running to the device is too small in diameter.
The hose, pipe or tubing is big enough in diameter, but too long.
The problem with either of these is line loss (follow that link if you want to do the math.) Put simply, the air wants to move faster than it’s physically permitted to. Any time fluid flows through a conduit of any sort, friction acts on it via contact with the inside surface of said conduit.
With smaller diameters, a larger percentage of the air flow is affected…no matter what diameter the line is, the air closest to the inner wall is affected by the friction generated. When diameter increases, the thickness of this affected zone doesn’t increase proportionally, so larger diameters mean less of the air is affected by friction. It also means there’s a lot more room (by a factor of the square of the radius, times pi…thanks, Archimedes!) for the air to flow through.
Likewise, with longer lengths, there’s more contact, which equals more friction. Length, however, is often a non-negotiable. You can’t just up and move a 100HP air compressor from one part of the plant to another. So, when we’re talking about selecting proper supply lines, we’re going to start with the distance from the compressed air header to our device, and pick the diameter that will give us the flow we need through that length. In fact, that’s exactly how to use the Recommended Infeed Pipe Size table in EXAIR’s Super Air Knife Installation & Maintenance Guide:
Once we have the correct line size (diameter,) let’s consider the fittings:
Tapered pipe threads (NPT or BSPT) are the best. They offer no restriction in flow, and are readily commercially available. If you’re using pipe, these are the standard threads for fittings. If you want to use hose, a local hydraulic/pneumatic shop can usually make hoses with the fittings you need, at the service counter, while you wait.
If you need to frequently break and make the connection (e.g., a Chip Vac System that’s used throughout your facility,) quick connects are convenient and inexpensive. Push-to-connect types are by far the most common, but a word of warning: they’re notoriously restrictive, as the inside diameter of the male end is markedly smaller than the line size. If you use them, go up a size or two…a quick connect made for 1/2 NPT connections will work just fine for a 1/4″ line:
The nice thing about these quick connects is that you don’t have to depressurize the line to make or break the connection. If you have the ability to depressurize the line, though, claw-type fittings (like the one shown on the right) provide the convenience of a quick connect, without the restriction in flow.
Proper air supply is key to performance of any compressed air product. If you want to know, at a glance, if you’re supplying it properly, install a pressure gauge right at (or as close as practical) to the inlet. Any difference in its reading and your header pressure indicates a restriction. Here’s a video that clearly shows how this all works:
I want to make sure you get the most out of your compressed air system. If you want that to, give me a call with any questions you might have.
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The Second Step to optimize your compressed air system is to Find and fix leaks in your compressed air system. The reason leaks are important to find and fix is because they can account for 20-30% of a compressors total output. A compressed air leak fixing process can save 10-20% of that lost volume.
Unintentional leaks will result in increased maintenance issues and can be found in any part of a compressed air system. Leaks can be found at a poorly sealed fitting, quick disconnects and even right through old or poorly maintained supply piping. Good practice will be to develop an ongoing leak detection program.
The critical steps needed for an effective leak detection program are as follows:
Get a foundation (baseline) for your compressed air use so you have something to compare once you begin eliminating leaks. This will allow you to quantify the savings.
Estimate how much air you are currently losing to air leaks. This can be done by using one of two methods.
Load/Unload systems, where T= Time fully loaded and t=Time fully unloaded:
Leakage percent = T x 100
(T + t)
Systems with other controls where V=cubic feet, P1 and P2=PSIG, and T=minutes
Leakage = V x (P1-P2) x 1.25
T x 14.7
Know your cost of compressed air so you can provide effectiveness of the leak fixing process.
Find, Document and Fix the leaks. Start by fixing the worst offenders, fix the largest leaks. Document both the leaks found and the leaks fixed which can help illustrate problem areas or repeat offenders, which could indicate other problems within the system.
Compare the baseline to your final results.
Repeat. We know you didn’t want to hear this but it will be necessary to continue an efficient compressed air system in your plant.