The first step to optimizing compressed air systems within an industrial facility is to get a known baseline. To do so, utilizing a digital flowmeter is an ideal solution that will easily install onto a hard pipe that will give live readouts of the compressed air usage for the line it is installed on. There is also an additional feature that we offer on the Digital Flowmeters that can help further the understanding of the compressed air demands within a facility.
The Pressure Sensing Digital Flowmeters are available from 2″ Sched. 40 Iron Pipe up to 8″ Sched. 40 Iron Pipe. As well as 2″ to 4″ Copper pipe. These will read out and with the additional Data Logger or Wireless Capability options record the information. When coupled with the wireless capability an alarm can be set for pressure drops that give live updates on the system as well as permits data review to see trends throughout the day of the system.
Generating a pressure and consumption profile of a system can help to pinpoint energy wasters such as timer-based drains that are dumping every hour versus level based drains that only open when needed. A scenario similar to this was the cause of an entire production line shut down nearly every day of the week for a local facility until they installed flowmeters and were able to narrow the demand location down to a filter baghouse with a faulty control for the cleaning cycle.
If you would like to discuss the best digital flowmeter for your system and to better understand the benefits of pressure sensing, please contact us.
EXAIR Corporation manufactures a variety of engineered compressed air products that have been solving myriad applications in industry for almost 37 years now. In order for them to function properly, though, they have to be supplied with enough compressed air flow, which means the compressed air supply lines have to be adequately sized.
A 20 foot length of 1/4″ pipe can handle a maximum flow capacity of 18 SCFM, so it’s good for a Model 1100 Super Air Nozzle (uses 14 SCFM @80psig) or a Model 110006 6″ Super Air Knife (uses 17.4 SCFM @80psig,) but it’s going to starve anything requiring much more air than those products. Since compressed air consumption of devices like EXAIR Intelligent Compressed Air Products is directly proportional to inlet pressure, we can use the flow capacity of the pipe, the upstream air pressure, and the known consumption of the EXAIR product to calculate the inlet pressure of a starved product. This will give us an idea of its performance as well.
Let’s use a 12″ Super Air Knife, with the 20 foot length of 1/4″ pipe as an example. The ratio formula is:
(P2 ÷ P1) C1 = C2, where:
P2 – absolute pressure we’re solving for*
P1 – absolute pressure for our published compressed air consumption, or C1*
C1 – known value of compressed air consumption at supply pressure P1
C2 – compressed air consumption at supply pressure P2
*gauge pressure plus 14.7psi atmospheric pressure
This is the typical formula we use, since we’re normally solving for compressed air consumption at a certain supply pressure, but, rearranged to solve for inlet pressure assuming the consumption will be the capacity of the supply line in question:
(C2 P1) ÷ C1 = P2
[18 SCFM X (80psig + 14.7psia)] ÷ 34.8 SCFM = 49psia – 14.7psia = 34.3psig inlet pressure to the 12″ Super Air Knife.
…we can extrapolate that the performance of a 12″ Super Air Knife, supplied with a 20 foot length of 1/4″ pipe, will perform just under the parameters of one supplied at 40psig:
Air velocity less than 7,000 fpm, as compared to 11,800 fpm*
Force @6″ from target of 13.2oz total, instead of 30oz*
*Performance values for a 12″ length supplied with an adequately sized supply line, allowing for 80psig at the inlet to the Air Knife.
Qualitatively speaking, if you hold your hand in front of an adequately supplied Super Air Knife, it’ll feel an awful lot like sticking your hand out the window of a moving car at 50 miles an hour. If it’s being supplied with the 20 foot length of 1/4″ pipe, though, it’s going to feel more like a desk fan on high speed.
The type of supply line is important too. A 1/4″ pipe has an ID of about 3/8″ (0.363″, to be exact) but a 1/4″ hose has an ID of only…you guessed it…1/4″. Let’s say you have 20 feet of 1/4″ hose instead, which will handle only 7 SCFM of compressed air flow capacity:
[7 SCFM X (80psig + 14.7psia)] ÷ 34.8 SCFM = 19psia – 14.7psia = 4.3psig inlet pressure to the 12″ Super Air Knife.
Our Super Air Knife performance chart doesn’t go that low, but, qualitatively, that’s going to generate a light breeze coming out of the Super Air Knife. This is why, for good performance, it’s important to follow the recommendations in the Installation Guide:
All Installation Guides for EXAIR Intelligent Compressed Air Products contain recommended air supply line sizes for this very reason. If you have any questions, though, about proper compressed air supply, give me a call.
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The generation of compressed air accounts for approximately 1/3 of all energy costs in an industrial facility. According to the Compressed Air Challenge, about 30% of that compressed air is lost through leaks. This means nearly 10% of your facilities energy costs are simply wasted through poor connections, faulty air valves, improper installation, etc. In addition to simply wasting money, compressed air leaks can also contribute to a variety of other operating losses. A leak can cause a drop in system pressure. When this occurs, end users may not operate as efficiently and has an adverse effect on production. This same drop in system pressure will also cause the equipment to cycle on/off more often, shortening the life of your compressor and other equipment. If the leaks cause an issue in supply volume, it may lead to the belief that more compressor capacity is necessary, further increasing your operating costs.
To put leaks in perspective (assuming energy costs of .10/ kWh), the folks at Compressed Air Challenge put it this way:
A $200/year leak cannot be felt or heard
A $800/year leak can be felt, but not heard
A $1,400/year leak can be felt and heard.
If you walk through your facility, how many leaks can you hear? These are only the REALLY bad ones!! So if we know that a large amount of compressed air is leaking, what do we do about it? ? A proper leak prevention plan is the key to success. Since these leaks are impossible to see and some cannot even be heard, you need a tool to help assist you. EXAIR’s model 9061 Ultrasonic Leak Detector is the right tool for the job. When compressed air leaks through a pipe, it creates an ultrasonic signature due to turbulence. While this sound is not always detectable by the human ear, this meter will allow you to locate leaks up to 20’ away by converting the ultrasonic signature into an audible sound.
The first step will be locating the leaks using an Ultrasonic Leak Detector and tagging them throughout the facility. Don’t let this overwhelm you!! If you have a larger facility, break it up into sections that can be completed in 1 day. This will allow you to decide which areas of the plant should be looked at first. Once you’ve located and tagged all of the leaks, rate them under two separate criteria so that you can prioritize what to fix first. Rate them based on the difficulty that it will take to fix them and also by the severity of the leak. Those that are severe yet easy to fix would make sense to begin fixing first. Those that may require a period of shutdown can be planned to fix at a more appropriate time.
When you’ve had the opportunity to fix them, don’t just forget about it. When new piping is installed, new lines are added, or anything involving compressed air is installed there is the potential for new leaks to develop. Set this as one of your regular PM activities and complete your own compressed air audit once a year. Implementing the process and maintaining it are the keys to your success.
If you have questions about developing a leak program or how to use the Ultrasonic Leak Detector, give us a call. An Application Engineer will be happy to help with the process and recommend some other methods to save on your compressed air supply.
Since air compressors use a lot of electricity to make compressed air, it is important to use the compressed air as efficiently as possible. EXAIR has six simple steps to optimize your compressed air system. (Click HERE to read). Following these steps will help you to cut your overhead costs and improve your bottom line. In this blog, I will cover a few tips that can really help you to save compressed air.
To start, what is an air compressor and why does it cost so much in electricity? There are two types of air compressors, positive displacement and dynamic. The core components for these air compressors is an electric motor that spins a shaft. Like with many mechanical devices, there are different efficiencies. Typically, an air compressor can put out anywhere from 3 SCFM per horsepower to 5 SCFM per horsepower. (EXAIR settles on 4 SCFM/hp as an average for cost calculations.) Equation 1 shows you how to calculate the cost to run your air compressor.
motor efficiency – average for an electric motor is 95%.
As an example, a manufacturing plant operates a 100 HP air compressor in their facility. The cycle time for the air compressor is roughly 60%. To calculate the hours of running time per year, I used 250 days/year at 16 hours/day. So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year. The electrical rate for this facility is $0.08/KWh. With these factors, the annual cost to run the air compressor can be calculated by Equation 1:
Cost = 100hp * 0.746 KW/hp * 2,400hr * $0.08/KWh / 0.95 = $15,077 per year in just electrical costs.
There are two major things that will rob compressed air from your system and cost you much money. The first is leaks in the distribution system, and the second is inefficient blow-off devices. To address leaks, EXAIR offers an Ultrasonic Leak Detector. The Ultrasonic Leak Detector can find hidden leaks to fix. That quiet little hissing sound from the pipe lines is costing your company.
A University did a study to find the percentage of air leaks in a typical manufacturing plant. For a poorly maintained system, they found on average that 30% of the compressor capacity is lost through air leaks. Majority of companies do not have a leak preventative program; so, majority of the companies fall under the “poorly maintained system”. 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. Or if we take the University study, the manufacturing plant above is wasting $15,077 * 30% = $4,523 per year.
The other area to check is air consumption. A simple place to check is your blow-off stations. Here we can decide how wasteful they can be. With values of 4 SCFM/hp and an electrical rate of $0.08/KWh (refence figures above), the cost to make compressed air is $0.25 per 1000 ft3 of air.
One of the worst culprits for inefficient air usage is open pipe blow-offs. This would also include cheap air guns, drilled holes in pipes, and tubes. These devices are very inefficient for compressed air usage and can cost you a lot of money. As a comparison, a 1/8” NPT pipe versus an EXAIR Mini Super Air Nozzle. (Reference below). As you can see, by just adding the EXAIR nozzle to the end of one pipe, the company was able to save $1,872 per year. That is some real savings.
By following the Six Steps to optimize your compressed air system, you can cut your energy consumption, improve pneumatic efficiencies, and save yourself money. With the added information above, you can focus on the big contributors of waste. If you would like to find more opportunities to save compressed air, you can contact an Application Engineer at EXAIR. We will be happy to help.