Bed Coffee and the Coanda Profile

Photo by Stocksnap and licensed by Pixabay

Every weekend my wife craves her “bed coffee”. I do my best to bring her some coffee in bed at least one, if not both weekend days. It makes her happy, and when she’s happy… The only thing I truly despise about this act of kindness is the actual pouring of the coffee. Now, I’m a decently smart guy but pouring this weekend coffee is a mess. Every time I end up with coffee on the counter, and many times on the mug. And when it gets on the mug it’s over, because it goes to the bottom of the mug and if I forget to wipe that off? Well, it gets on the sheets, because she inevitably rests her coffee on the sheets, and somehow this is my fault, and now she’s not happy anymore… (in fairness, she is still happy and just busts my chops about this part). But why does this happen to me?

It is a little refreshing to realize that I am just a victim of this scientific phenomenon called the Coanda profile. When I start to pour the coffee, the stream adheres to the outer wall of the coffee pot. This causes the coffee to run down the pot and onto the counter, where the cups are sitting (getting that mug bottom soaked in coffee). This is partially caused by the Coanda effect, and partially caused by me not being awake enough to outsmart a coffee pot. The simple solution is to simply increase the flow rate, right? This is correct however, this does not eliminate the Coanda Effect. In fact, even if you are smarter than me you will notice, after you pour the coffee, there is liquid on the side of the pot. That liquid may only be in the form of steam but it’s there, just to a lesser degree. The solution to avoid the mess, is to adjust the pot so that the pour angle is such that gravity overpowers the majority of the Coanda effect. Many times, in my case, this adjustment is too late…

The Coanda phenomena closely depends on several factors, the speed of the jet flow (pouring at a steeper angel), the flow rate (pouring more or less volume over time), and the profile of the container. I believe that a mad scientist invented my particular coffee pot with full intention of messing up countertops all over the world. In fact, he may be a super villain.

At EXAIR, we utilize the Coanda Profile to our benefit on most products. Here are 2 products that are perfect examples of how we use the Coanda Profile to maximize the performance of our products.

Air Amplifiers use the Coanda Effect to generate high flow with low consumption.
Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

As you can see above, using the Coanda Profile correctly, dramatically increases the efficiency and the entrainment of air in our products. Between the Coanda effect, and the air entrainment, some of our products like the Super Air Amplifiers can output up to 25 times the amount of air that they consume.

Please contact us at anytime to see how the intelligent compressed air products of EXAIR can assist you in your application. And, don’t forget about bed coffee, it’s a win win for you and your spouse…

Thank you for stopping by,

Brian Wages

Application Engineer

EXAIR Corporation
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Cover Photo by monileoni and licensed by Pixabay

Villain image by chrismaguirang and licensed by Pixabay

Air Operated Conveyors: Line Vacs

Get rid of your buckets and ladders, and add an EXAIR Line Vac. These small units can move large volumes of material. They are a perfect solution for moving things like plastic pellets, textiles, food products, pills/tablets, granules and much more. By adding a small amount of compressed air through the directed nozzles on the Line Vac, you will create a vacuum on one end and a high flow of air on the other to lift and or push your material up and over to a new location.

EXAIR Line Vacs: For bulk material conveyance through lines from 3/8″ to 6″, in aluminum, 303SS, 316SS, or abrasion resistant hardened alloy, available from stock with the widest variety of connections in the industry.

With multiple sizes from 3/8″ up to 4″ (up to 6″ in our Light Duty Options), we can help you select the best size for your application. In addition to sizes, we offer these is the following materials; Aluminum, 303 Stainless Steel, 316 Stainless Steel, High temp 303 and 316 Stainless Steel, a hardened alloy, and in a flanged 316 Stainless Steel. We offer these in the Standard Fitting, a Threaded Fitting, and a Sanitary Flange Fitting. Lastly, we can make these in custom materials and sizes if you have the need.

Line Vacs can convey many things.

We have testing data from materials of many weights and sizes to compare your project to, so that we can help you choose the best size for your application. The information we need starts with the type and size of material. Keep in mind that we will be aerating your product, so we need to be cautious of creating combustible dusts such as flours, grains, pesticides, fine powders and much more. Beyond this, we need to understand the surface area on your product that the air will catch.

We will then need to understand the vertical and horizontal lengths that you need to move your media. For instance, up 10 feet and over 5 feet… With this, we will need to understand the “turn”. Keeping in mind that this is about air flow, 90° turns need to be taken in to account. We will need to add 10-15 feet of length in our calculations to overcome a 90°turn. If you can engineer a gradual turn, rather than an abrupt one, your product will flow much smoother. Next, we will enquire about the type of container your media is being conveyed from, and to. Example, it is going from a super sack, to the dumpster, or from a drum to a hopper.

Next, we need to have an accurate bulk density, or pounds per cubic feet (or kg/m3). If this is unknown, we can easily find this by putting your product in a container and weigh it. We simply multiply the Length x Width x Height of the container, and divide that by the weight. This will give us the pounds per cubic foot. Finally, we need to know how many pounds per minute do you need to have conveyed.

Be sure to check out our promotion on Line Vacs as well.

With the above information in hand, please reach out and discuss your data with myself, or any of the application engineers to determine the Line Vac that is perfect for your application.

Thank you for stopping by,

Brian Wages

Application Engineer

EXAIR Corporation
Visit us on the Web
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3-1/2 EXAIR Pro Tips for Compressed Air Use

EXAIR offers industry leading Intelligent Compresses Air Products. Our products are engineered to comply with all relevant OSHA standards and are CE certified. When you purchase an EXAIR product, be it a Super Air Knife or a brass bulkhead fitting, you are expecting to receive a high quality and high performing product, and you will. If the product is not performing there is a very high probability that the problem is not the product.

So whatever could it be? And how can we fix the issue? Air supply going to the product is a common issue, so first we need to insure that there is a steady flow of the appropriate pressure and volume of air. Even though you may have a 100HP compressor, the distance form the product, the size of the pipes delivering the air, the smoothness of the inside of the pipes (is there internal rust and buildup), leaks and other restrictions of air flow rate all contribute to the overall performance.

A large majority of the product performance issues that are brought to us are caused by insufficient air supply in one form or another. Sometimes this is due to the overall size of the system, but many times it is at the point of use. Let’s assume that you have the right sized compressor to power all features in the shop. These next items are where we would want to focus and correct.

EXAIR Digital Flowmeter

Pro tip #1 – Use EXAIR Digital Flowmeters to monitor your air consumption. You should have a log of how much each compressed air tool / machine uses, and compare that to how much air is traveling down that leg of your facility. Leaks, corrosion, rust, and accidents happen. By monitoring and logging your SCFM in each major leg of your system, you will easily be able to narrow down root problems, and track leaks. You will also have solid answer when asked – “Do you have enough air for this?”.

Pressure Regulators “dial in” performance to get the job done without using more air than necessary.

Pro Tip #2 – Use a Tee Fitting and install a Pressure Regulator with Gauge at the point of use. This allows you to see, and control the pressure for each product. This removes all questions of air pressure at the point of use. Although your system seems large enough, many times the pressure is less at the point of use, due to restrictions, unknown leaks etc… Having the information from tip #1 and #2, you will easily be able to identify if your issue is the system, or the tool.

Pro Tip #2.5 – Turn it down (the pressure) if you can… Operate each compressed air application at a pressure just high enough for your desired result – not necessarily full line pressure. We have discussed in many other blogs how compressed air is your 3rd or 4th highest utility. If you optimize the pressure per application, you can save dollars. As a rule of thumb, if your system is operating at the 100 psig level, lowering the pressure by 2 psig will save 1% of energy used by the air compressor. A great example of this would be our Super Air Knives. Optimal use is at 80 psig, and “X” SCFM (based upon length of the Super Air Knife). At 80 psig and the proper SCFM, this flow will feel like having your hand out the window of your car when you are driving about 50 MPH. Your application may not need that much air flow, to get the job done. Turn it down and test it. Start at 80 psig and using the tools from tip #2, turn it up or down until your needs are met. Many of our products do not need to be used at full pressure to effectively solve your process problem.

Pro tip #3 – Use the proper sized lines, connectors and fittings. Pipe restriction can kill performance. Quick connects can be very problematic. Most quick connects are rated at the same size as the incoming pipe, tube or hose, but may actually have a much smaller inner diameter. As you can imagine, this oversight can cause significant performance issues, and end up costing more lack of production or defective product. Be it a quick connect, or any other connector or fitting, it is imperative not to restrict the air. This will result in problems, and lack of performance.

Please do not hesitate to reach to discuss any performance issues, or find out how we can help.

Thank you for stopping by,

Brian Wages

Application Engineer

EXAIR Corporation
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Line Vac Air Operated Conveyors: What to Know When Specifying

So you are thinking about using a Line Vac… Is it time to replace that ladder and bucket, and automate? There are many factors involved when deciding to use a conveyor system such as EXAIR Line Vacs. First of all let’s take a look at your product that needs conveyed. Will the integrity of your media be compromised by adding this much air to it? How heavy is it? What type of (how much) surface area does it have?

You know your media better than most. You should be able to answer most of those questions pretty easily, but what about the weight? For the weight, we work best knowing the bulk density, or pounds per cubic foot. If you do not readily know, this is easily found by finding the weight of your media in a box (or container). Then take the total cubic inches of the box (L x W x H) and divide that by 1728 (cubic inches per cubic foot), this will give you the cubic feet of that box. Then you simply divide the weight by the cubic feet, and you now have the density.

Line Vacs can convey many things.

Next we need to focus on your conveyance run. We would like to know what type of container is your product sitting in? A super sack, a hopper, a drum, a box? And where is it going? How far away is the destination hopper, dumpster, assembly station, etc.? This will help us determine the type of fitting or tools necessary to extract or release the media. How high do you need to go? How far horizontally? Our Line Vacs, are amazing, but they do have their limits. We will also need to know if there are any turns, and at what angles. Turns are many times unavoidable, but will have an adverse effect on the conveyance run as the airflow is halted and or deflected. Is there a way to minimize or eliminate the turns?

The final question is; how many pounds per minute do you need to be conveyed?

With the size, mass, and geometry of your parts, along with the vertical lift length, and the horizontal conveyance length, added to the turns and twists, you are just about ready to call one of our our application engineers for recommendations. We have some comparison materials for conveyance rates, to get you close to your actual needs. Here are some published conveyance rates as well:

There is one more part to this equation. What type and size of Line Vac will you need? EXAIR has many types of Line Vacs to choose from. As with most products, we have options that take into consideration the temperature and the abrasiveness of your product. We also have options to fit the type of conveyance hose or pipe you want to use , such as sanitary fittings, or threaded. And since we manufacture these right here in Cincinnati, OH, we can make custom Line Vacs for customers fairly quickly. We have designed and manufactured them with custom bolt on flanges, special materials or inlet sizes to name a few.

EXAIR Line Vacs: For bulk material conveyance through lines from 3/8″ to 6″, in aluminum, 303SS, 316SS, or abrasion resistant hardened alloy, available from stock with the widest variety of connections in the industry.

Please do not hesitate to call. We will be happy to help you with any technical questions about our products.

Application Engineer

Brian Wages

EXAIR Corporation
Visit us on the Web
Follow me on Twitter

Yellow Ladder pic from OpenClipart-Vectors / 27385 & Bucket Pic from Jazella / 704 images on a Pixabay License