“You can’t manage what you don’t measure” is a well-known axiom in engineering & process improvement circles. We talk to callers every day who are keen on conserving compressed air use in their facilities by making a few tweaks, considering a complete overhaul, or more often, some point in between. Bottom line (literally) is, compressed air isn’t cheap, so small gains in efficiency can add up. And large gains can be complete game-changers…following our Six Steps To Optimizing Your Compressed Air System has resulted in users being able to shut down 50 and 100 HP air compressors, saving thousands of dollar A MONTH in operating costs.
Step #1 is measurement, and that’s where the EXAIR Digital Flowmeter comes in. They’re easy to install, highly accurate, extremely reliable, and available for just about any size pipe used for compressed air distribution. They can output a 4-20mA signal straight from their PCB board, or serial comms (RS485) through an optional control board. USB Data Loggers and Summing Remote Displays have proven to be value-added accessories for data management as well.
If you want to go wireless, we can do that too: using ZigBee mesh network protocol, a radio module is installed in the Digital Flowmeter with wireless gateway to transmit data to an Ethernet connected gateway. The transmitting range is 100 ft (30 meters,) and the data can be passed from one radio module to another, allowing for multiple Digital Flowmeter installations to extend the distance over which they can communicate with the computer you’re using for central monitoring. Advantages include:
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. Following these steps will help you to cut electrical costs, reduce overhead, and improve your bottom line. In this blog, I will cover the first step – Measure the air consumption to find sources that use a lot of compressed air.
Information is important to diagnose wasteful and problematic areas within your compressed air system. To measure air consumption, flow meters are used to find the volume or mass of compressed air per unit of time. Flow rates are very useful data points to find problems like leaks, over-use in blow-offs, waste calculations, and comparison analysis.
There are many different types of flow meters. Many of them entail a breakdown of your current compressed air lines by cutting, welding, or dismantling for installation. This will add cost in downtime and maintenance staff. But, not with the EXAIR Digital Flowmeters. In this blog, I will share the features and benefits of the Digital Flowmeters including options for you to start measuring and optimizing your compressed air system in Step 1.
Overall, it only takes a few minutes to install and start measuring. The installation kit comes with a drill bit and a drill guide to properly locate the two holes on the pipe. The Digital Flowmeter uses a clamp to mount to the pipe and to seal the area around the probes. Once it is powered, the unit is ready to measure the air flow inside the pipe with a large LED display. The display can be customized to show flow readings in three different units; SCFM, M3/hr or M3/min; and, it can display the Daily Usage and Cumulative Usage.
To get started, the EXAIR Digital Flowmeter is a thermal dispersion device that can accurately measure compressed air flows. They use two sensing probes for comparative analysis. One probe is a temperature sensing probe, and the other is a flow-sensing probe. By comparing these, the Digital Flowmeter can measure precisely the mass air flow without needing to be recalibrated. They are a cost-effective, accurate, and simple way to measure compressed air flows.
EXAIR stocks a large volume of Digital Flowmeters to ship same day for U.S. and Canadian customers. We also offer a 30-day unconditional guarantee to try them out. We stock meters for pipe diameters from ½” NPT to 4″ NPT Schedule 40 black pipe. EXAIR can also offers flow meters up to 8″ NPT black pipe; copper pipes with diameters from 3/4″ to 4″, and aluminum pipes with diameters ranging from 40mm to 101mm. If you have another type of piping for your compressed air system, you can give us the material, O.D. or I.D., and wall thickness. We may still be able to get a Digital Flowmeter for you.
For measuring, all the units come standard with a 4 – 20mA analog output. Per your request, we can change this signal to a serial output for RS-485 or Ethernet connections. What more can we offer with the EXAIR Digital Flowmeter? Options. Options upgrade the flow meters to better suit your application. Here is a list below:
USB Data Logger: This option allows for a recording of the flow information. With a software download, you can setup the USB Data Logger to record the flows from once a second (roughly 9 hours of storage) to every 12 hours. After the data points are recorded, you can then download the information into the software to review. Then the information can be uploaded into an Excel program to do further analysis.
Summing Remote: With compressed air pipes running along the ceiling and walls, reading the Digital Flowmeter may be difficult. The Summing Remote has a 50-foot (15 meter) cable to bring the LED display into viewing. The Summing Remote is powered by the Digital Flowmeter, and it can be positioned at eye level, inside managers’ rooms, or around large equipment for monitoring.
Wireless Capability: Our latest Digital Flowmeter now has wireless capabilities. They use a Zigbee® communications to pick up flow readings from other flow meters and the Gateway. The Gateway can detect over 100 Digital Flowmeters in your facility. From the Gateway, the information is transferred through a LAN. You can record and analyze the flow information from each meter on the network with our EXAIR® Logger Software. You can set limits to send warnings when your compressed air system is using too much or too little of compressed air. This technology makes it very easy for measuring your compressed air system in the entire facility without having to be there.
Hot Tap Digital Flowmeter: This option is a great way to install a Digital Flowmeter to the pipe without shutting down the compressed air line. We offer this option for 2″ and larger flow meters for steel and copper pipes. It gives a quick and easy way to attach if you have a 24-hour operation or a critical process that needs to continue to run.
Pressure Sensing Digital Flowmeter: If you would like to know the compressed air flow and the air pressure, this option will be able to do this. They are available with the Digital Flowmeters for steel and copper pipes that are 2″ and larger, and for the aluminum piping that is 50mm and larger. This option can display pressure units in either PSI or Bar right on the same LED display that shows the flow readings.
Block-Off Rings: If you want to move your Digital Flowmeter, the Block-Off Rings will be able to cover the openings in your compressed air pipe. They seal around the drilled opening when the Digital Flowmeter is removed from the pipe. They are reusable; so, they can be removed if you want to remount the Digital Flowmeter in the same spot. If you want to use one flow meter in different locations, the Block-Off Rings allow you do this.
When you need to analyze your pneumatic components, flow is an important point in diagnosing the overall “health” of your compressed air system. The EXAIR Digital Flowmeter can give you that important data point. With optimization, you can cut your energy consumption, improve pneumatic efficiencies, and save yourself money. This blog is an overview of Step 1 of six steps. You may have more questions; and, that is great! You can find them in other EXAIR blogs, or you can contact an Application Engineer at EXAIR.
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.
Step 4 of the Six Steps to Optimizing your compressed air is to turn off your compressed air when it is not in use. This step can be done using two simple methods either by using manual controls such as ball valves or automated controllers such as solenoid valves. Manual controls are designed for long use and when switching on and off are infrequent. Ball Valves are one of the most commonly used manual shut offs for compressed air and other fluids.
Automated controllers allow your air flow to be tied into a system or process and turn on or off when conditions have been met. Solenoid valves are the most commonly used automated control device as they operate by using an electric current to open and close the valve mechanism within. Solenoid valves are some of the more versatile flow control devices due to the fact that they open and close almost instantaneously. Solenoid valves can be used as manual controls as well by wiring them to a switch or using simple programming on a PLC to turn the valve on or off using a button.
Some good examples of automated controllers are EXAIR’s Electronic Flow Controller (a.k.a. EFC) and EXAIR’s Thermostat controlled Cabinet Coolers.
The EFC system uses a photo eye to detect when an object is coming down the line and will turn on the air for a set amount of time of the users choosing. This can be used to control the airflow for all of EXAIR’s products. EXAIR’s Thermostat controlled Cabinet Coolers are used to control the internal temperature of a control cabinet or other enclosures. This is done by detecting the internal temperature of your cabinet and when it has exceeded a temperature which could damage electrical components it will open the valve until a safe temperature has been reached, then turn off.
By turning off your compressed air, whether it be with manual or automated controllers, a company can minimize wasted compressed air and extend the longevity of the air compressor that is used to supply the plants air. The longevity of the air compressor is increased due to reduced run time since it does not need to keep up with the constant use of compressed air. Other benefits include less use of compressed air and recouped cost of compressed air.
If you have questions about our compressed air control valves 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
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.
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!