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.
All compressed air systems will have some amount of leakage. It is a good idea to set up a Leak Prevention Program. Keeping the leakage losses to a minimum will save on compressed air generation costs, and reduce compressor operation time which can extend its life and lower maintenance costs.
The Compressed Air Challenge estimates an individual compressed air leak can cost thousands of dollars per year when using $0.07/kWh.
1/16″ diameter hole in excess of $700/year
1/8″ hole in excess of $2900/year
1/4″ hole in excess of $11,735 per year
There are generally two types of leak prevention programs:
Leak Tag type programs
Seek-and-Repair type programs
Of the two types, the easiest would be the Seek-and-Repair method. It involves finding leaks and then repairing them immediately. For the Leak Tag method, a leak is identified, tagged, and then logged for repair at the next opportune time.
A successful Leak Prevention Program consists of several important components:
Document your Starting Compressed Air Use – knowing the initial compressed air usage will allow for comparison after the program has been followed for measured improvement.
Establishment of initial leak loss – See this blog for more details.
Determine the cost of air leaks – One of the most important components of the program. The cost of leaks can be used to track the savings as well as promote the importance of the program. Also a tool to obtain the needed resources to perform the program.
Find the leaks – Leaks can be found using many methods. Most common is the use of an Ultrasonic Leak Detector, like the EXAIRModel 9061. See this blog for more details. An inexpensive handheld meter will locate a leak and indicate the size of the leak.
Record the leaks – Note the location and type, its size, and estimated cost. Leak tags can be used, but a master leak list is best. Under Seek-and-Repair type, leaks should still be noted in order to track the number and effectiveness of the program.
Plan to repairs leaks – Make this a priority and prioritize the leaks. Typically fix the biggest leaks first, unless operations prevent access to these leaks until a suitable time.
Record the repairs – By putting a cost with each leak and keeping track of the total savings, it is possible to provide proof of the program effectiveness and garner additional support for keeping the program going. Also, it is possible to find trends and recurring problems that will need a more permanent solution.
Compare and publish results – Comparing the original baseline to the current system results will provide a measure of the effectiveness of the program and the calculate a cost savings. The results are to be shared with management to validate the program and ensure the program will continue.
Repeat As Needed – If the results are not satisfactory, perform the process again. Also, new leaks can develop, so a periodic review should be performed to achieve and maintain maximum system efficiency.
An effective compressed air system leak prevention and repair program is critical in sustaining the efficiency, reliability, and cost effectiveness of an compressed air system.
If you have questions about a Leak Prevention Program or any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.