When I see turbulent flow vs. laminar flow I vaguely remember my fluid dynamics class at the University of Cincinnati. A lot of times when one thinks about the flow of a liquid or compressed gas within a pipe they want to believe that it is always going to be laminar flow. This, however, is not true and there is quite a bit of science that goes into this. Rather than me start with Reynolds number and go through flow within pipes I have found this amazing video from a Mechanical Engineering Professor in California. Luckily for us, they bookmarked some of the major sections. Watch from around the 12:00 mark until around the 20:00 mark. This is the good stuff.
The difference between entrance flow, turbulent flow and laminar flow is shown ideally at around the 20:00 mark. This length of piping that is required in order to achieve laminar flow is one of the main reasons our Digital Flowmeters are required to be installed within a rigid straight section of pipe that has no fittings or bends for 30 diameters in length of the pipe upstream with 5 diameters of pipe in length downstream.
This is so the meter is able to measure the flow of compressed air at the most accurate location due to the fully developed laminar flow. As long as the pipe is straight and does not change diameter, temperature, or have fittings within it then the mass, velocity, Q value all stay the same. The only variable that will change is the pressure over the length of the pipe when it is given a considerable length.
Another great visualization of laminar vs. turbulent flow, check out this great video.
If you would like to discuss the laminar and turbulent flow please contact an Application Engineer.
The Electronic Flow Control, or EFC, is an EXAIR Optimization product to reduce air consumption in your facility. Saving this electricity that is used to make compressed air will save you money and will help you to “Go Green”. The EFC has 8 different modes that uses a timing sequence with a Photoelectric Sensor to turn on/off a solenoid valve. In this video, I will go through each mode to demonstrate how the Electronic Flow Control will perform.
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.
Leaks are one of the major wastes of compressed air that could happen in a system. But what affect can leaks have on your system and how can these leaks be found? Total leaks in a compressed air line can account for wasting almost 20-30% of a compressors output. These leaks can commonly be found in areas were a pipe comes in contact with a joint, connections to devices that use the compressed air, and storage tanks.
There are four main affects that a leak in your compressed air system can have and they are as follows; 1) cause in pressure drop across the system, 2) shorten the life of almost all supply system equipment, 3) increased running time of the compressor, and 4) unnecessary compressor capacity.
A pressure drop across your compressed air system can lead to a decreased in efficiency of the end use equipment (i.e. an EXAIR Air Knife or Air Nozzle). This adversely effects production as it may take longer to blow off or cool a product or not blow off the product well enough to meet quality standards.
Leaks can shorten the life of almost all supply system components such as air compressors, this is because the compressor has to continuously run to make up for the air loss from the leak. By forcing the equipment to continuously run or cycle more frequently means that the moving parts in the compressor will wear down faster.
An increased run time due to leaks can also lead to more maintenance on supply equipment for the same reasons as to why the life of the compressor is shortened. The increase stress on the compressor due to unnecessary running of the compressor.
Leaks can also lead to adding unnecessary compressor size. The wasted air that is being expelled from the leak is an additional demand in your system. If leaks are not fixed it may require a larger compressor to make up for the loss of air in your system.
All of these effects are an additional cost that is tacked onto the already existing utility cost of your compressed air. But luckily there are ways to find these leaks and patch them up before it can get to out of control. One of the ways to help find leaks in your system is the EXAIR’s affordable Ultrasonic Leak Detector. This leak detector uses ultrasonic waves to detect were costly leaks can be found so that they can be patched or fixed.
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.
Cody Biehle Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
After getting a baseline measurement of the air consumption in your facility and locating and fixing leaks in your system, it’s time to begin implementing some changes. Step 3 of the 6 Steps to Optimizing Your Compressed Air System covers upgrading your blowoff, cooling, and drying operations using engineered compressed air products.
This step can have the most impact when it comes to your bottom line. The energy costs associated with the generation of compressed air make it one of the most expensive utilities for any industrial environment. Because of this, we need to ensure that the places in your facility that are using compressed air are doing so efficiently.
EXAIR manufactures a variety of products that can help to ensure you’re using your compressed air in the best way possible. What it may seem simple, easy, and cheap to use something like an open-ended pipe or tube for blowoff, the fact of the matter is that the volume of air that these homemade solutions use quickly make them more expensive. Super Air Nozzles have been designed to entrain ambient air along with the supplied compressed air, allowing you to achieve a high force from the output of the nozzle while keeping compressed air usage to a minimum. In addition to saving air, they’ll also provide a significant reduction in overall sound level.
Another product that can be used to increase the efficiency of your blowoff processes is the Super Air Knife. Available in lengths ranging from 3”-108” and in a variety of materials, the Super Air Knife is the ideal replacement for inefficient drilled pipes. Again, it may seem cheaper to just drill a few holes in a pipe whenever you need to cover a wide area but the volume of air consumed in addition to the incredibly high sound level will quickly drain your compressor. The Super Air Knife is also designed to entrain ambient air, at a rate of 40:1! Allowing you to take advantage of the free ambient air in addition to the supplied air.
Let’s compare the costs difference between a homemade drilled pipe and EXAIR’s Super Air Knife. The Super Air Knife has a precisely set air gap across the full length of the knife, allowing for an efficient and quiet laminar airstream. When compared to a drilled pipe, the air consumption is dramatically reduced as is the sound level. For example, let’s take an 18” section of drilled pipe, with 1/16” diameter holes spaced out every ½”. At 80 PSIG, each hole consumes 3.8 SCFM. With a total of 37 holes, this equates to a total of 140.6 SCFM.
3.8 SCFM x 37 = 140.6 SCFM
A Super Air Knife, operated at 80 PSIG with .002” stock shim installed will consume a total of 2.9 SCFM per inch of knife. An 18” SAK would then consume just 52.2 SCFM.
2.9 SCFM x 18 = 52.2 SCFM
140.6 SCFM – 52.2 SCFM = 88.4 SCFM saved
Replacing an 18” drilled pipe with a Super Air Knife represents a total reduction in compressed air consumption of 63%! How much does this equate to in $$$? A reasonable average of cost to generate compressed air is about $0.25/ 1000 SCF. Let’s assume just a 40hr workweek:
88.4 SCFM x 60 mins x $0.25/1000 SCF = $1.33/hr
$1.33 x 40hr workweek = $53.20 USD
$53.20 x 52 weeks/year = $2,766.40 USD in yearly savings
The 2019 list price on a Model 110018 Super Air Knife is $397.00. By replacing the homemade solution with an 18” Super Air Knife, the return on investment is just over 38 working days of an 8-hr shift. If your plant runs multiple shifts, or works on weekends, it pays for itself even quicker.
Not only are these homemade solutions expensive to operate, they’re not safe either. Familiarize yourself with both OSHA 29 CFR 1910.95(a) and 29 CFR 1910.242(b) and you’ll learn just how expensive it can be if you were to be found using these devices during a random OSHA inspection. Make sure you’re utilizing the most expensive utility as efficiently and safely as possible. If you need help with determining which products are best suited for your application, give us a call. Our team of Application Engineers is ready to help!
It is estimated that typically plants can waste up to 30 percent of their generated compressed air and that cost is substantial. Considering the average cost to generate compressed air here in the Midwest is .25 cents per 1,000 Standard Cubic Feet, that translates into .075 cents for every .25 cents spent! Compounded with the fact that energy costs have doubled in the last five years, it couldn’t be a better time to make your air compressor system more efficient.
The following steps will help you save air and in turn save money.
Measure the air consumption to find sources that use a lot of compressed air.
Knowing where you stand with your compressed air demand is important to be able to quantify the savings once you begin to implement a compressed air optimization program. Placing a value upon your compressed air consumption will also allow you to place a value on its costs and the savings you will reap once you start to reduce your consumption. (EXAIR’s Digital Flow Meter)
Find and fix the leaks in your compressed air system.
Not fixing your compressed air system leaks can cause your system pressure to fluctuate and affect your equipment negatively. It may cause you to run a larger compressor than necessary for your compressed air needs and raise your total costs. Or it could cause your cycle and run times to increase which leads to increased maintenance to the entire system. (EXAIR’s Ultrasonic Leak Detector)
Upgrade your blow off, cooling and drying operations using engineered compressed air products.
Your ordinary nozzle with a through hole and a cross drilled hole can be an easy choice based upon price, but if you do not consider the operating cost you do not really know how much it is costing you. An Engineered Air Nozzle will pay for itself and lower operating costs quickly. Engineered Air Nozzles are the future of compressed air efficiency and are made to replace ordinary nozzles, homemade nozzles and open line blow offs. Engineered Nozzles reduce air consumption and noise levels; ordinary nozzles cannot compete. Engineered Nozzles maintain safety features and can qualify for an energy savings rebate from a local utility; ordinary nozzles fall short. Open blow off or homemade blow off applications typically violate OSHA safety standards; Engineered Nozzles do not. (EXAIR’s Air Nozzles)
Turn off the compressed air when it is not in use.
Automated solutions add solenoid valves and run them from your machine controls. If the machine is off, or the conveyor has stopped – close the solenoid valve and save the air. And blow off applications can benefit from any space in between parts by turning the air off during the gaps with the aid of a sensor and solenoid. (EXAIR’s automated Electronic Flow Control)
Use intermediate storage of compressed air near the point of use.
Also known as secondary receivers, intermediate air storage is especially effective when a system has shifting demands or large volume use in a specific area. Intermediate storage is the buffer between a large demand event and the output of your compressor. The buffer created by intermediate storage (secondary receiver) prevents pressure fluctuations which may impact other end use operations and affect your end product quality. (EXAIR’s Receiver Tanks)
Control the air pressure at the point of use to minimize air consumption.
This is a very simple and easy process, all it requires is a pressure regulator. Installing a pressure regulator at all of your point of use applications will allow you to lower the pressure of these applications to the lowest pressure possible for success. Lowering the pressure of the application also lowers the air consumption. And it naturally follows that lower air consumption equals energy savings. (EXAIR’s Pressure Regulators)
By increasing your awareness of the health of your air compressor system and implementing a PM program you can significantly reduce your costs from wasted energy and avoid costly down time from an out of service air compressor.
If you would like to discuss improving your compressed air efficiency or any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.
As margins get tighter and cost of manufacturing climbs, industries are looking into different areas to be more efficient. A big focus nowadays is in their compressed air system. Why is this? Manufacturers are starting to realize that it takes an abundant amount of electricity to make compressed air. That is why EXAIR manufactures compressed air products for optimization to get the best efficiency. But what many manufacturers don’t realize is that quiet little hissing sound from there compressed air lines is costing them much money. That is why EXAIR has the Ultrasonic Leak Detector.
Energy Star, a federal voluntary program ran by the Environmental Protection Agency, offers energy-efficient solutions. EXAIR has partnered with Energy Star because it underscores our commitment to improve energy savings. They even wrote an excerpt about compressed air leaks here: Energy Tips: Minimize Compressed Air Leaks. With compressed air leaks, it can be as much as 30% of your compressed air usage.
When a leak occurs, it emits an ultrasonic noise. The EXAIR Ultrasonic Leak Detector can pick this up. It has a frequency range from 20 KHz to 100 KHz, above human hearing, so it can make the inaudible leaks, audible. With three sensitivity ranges and LED display, you can find very minute leaks. It comes with headphones and two attachments; the parabola attachment to find leaks up to 20 feet (6 meters) away, and the tube attachment for local proximity to define the exact location of the leak.
In the Energy Tips from Energy Star, they reference estimated leak rates and costs associated with these leaks. They also recommend a leak prevention program with reference materials to help improve energy savings. As part of that program, an Ultrasonic Leak Detector is the best way to begin.
To tell a common success story about the Ultrasonic Leak Detector, an EXAIR customer had a 50-horsepower air compressor. It started to overwork, overheat, and occasionally shut down. He thought that he would need to buy a larger air compressor to keep his plant running. In discussing his problems and requirements, he decided to purchase an Ultrasonic Leak Detector from EXAIR to check for leaks as a possible cause. He checked every fitting and connection in his facility. When he finished checking the compressed air system, he found 91 leaks. (You will be surprised with your system if it is not well maintained).
If we look at a very small 1/16” (1.6mm) diameter hole at 80 PSIG (5.5 bar), it will cost you $360 a year per leak (based on 6000 working hours per year). Thus, 91 leaks at $360/year will equal $32,760 per year. After the fittings were reworked with piping compound, the compressor was back operating in a normal range. There was no need to buy a larger air compressor with capital funds, and he was able to save $32,760 a year by finding and fixing the leaks.
As a little secret with the Ultrasonic Leak Detector, it can do more than find compressed air leaks. Any issue that creates an ultrasonic noise, the Ultrasonic Leak Detector can find it. This will include air damper seals, circuit breakers, cracked rubber belts, gas burner leaks, refrigerant leaks, worn bearings, and air brake systems on trucks. It is a handy tool to find potential issues or problems in other areas other than compressed air systems.
For optimization of your compressed air system, it is very important to find and correct leaks in your piping system. The Ultrasonic Leak Detector can help you do that. It is an inexpensive way to solve an expensive problem, compressed air leaks. If you would like to discuss the features and benefits in more detail, you can contact an Application Engineer at EXAIR. We will be glad to help you.