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
Visit us on the Web
Follow me on Twitter

Cover Photo by monileoni and licensed by Pixabay

Villain image by chrismaguirang and licensed by Pixabay

EXAIR Compliance with OSHA 1910.242(b)

OSHA Standard 1910.242(b) discusses the use of compressed air for cleaning and blowoff. It states that the use of compressed air for cleaning purposes is prohibited if the dead-ended pressure exceeds 30 psig. This phrase means the downstream pressure of the air nozzle or gun, used for cleaning purposes, will remain at a pressure level below 30 psig for all static conditions. In the event that dead ending occurs, the static pressure at the main orifice shall not exceed 30 psi. If it does exceed this pressure, there is a very high potential for it to create an air embolism. An air embolism, left untreated, can quickly impede the flow of blood throughout the body. This can lead to stroke, heart attack, and sometimes death.

So making sure you are in compliance with 1910.242(b) is truly a life and death situation. Most people believe that lowering the pressure to the blow off device is the only method to keep their operators safe from an air embolism. However this can become a problem when you really need the force of greater than 30 PSIG to complete your operation. We at EXAIR want to give you the flexibility to run at any pressure with out the risk of building that 30 PSI of dead-end pressure! We do this with our line of Intelligent Compressed Air® nozzles! All of EXAIR’s Air Nozzles are designed so that the flow cannot be dead-ended. The fins on the Super Air Nozzles are not only useful in amplifying the force by drawing in ambient air, but they also prevent an operator from completely obstructing the airflow.

Another great example of this is our 2″ Flat super air nozzle. The design not only allows the nozzle to amplify the air flow in the blast of air, the over hang will not let the dead end pressure build as it can escape around the edges and bottom!

2″ Flat Super Air Nozzle

If you’ve got questions about compressed air safety or have an existing blowoff in place that does not adhere to this OSHA directive, give us a call. We’ll be sure to recommend a solution that will keep your operators and wallets safe!

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

EXAIR Soft Grip Safety Air Gun

EXAIR Safety Air Guns use engineered air nozzles for high performance. Inexpensive air guns are sold through many catalogs and industrial supply companies. Most have triggers or other parts that break quickly. Their performance is similar to open pipe, where they simply blow a lot of compressed air. In addition to high air consumption, many produce noise levels that violate OSHA requirements. Some even generate dangerous dead end pressures that can result in serious or fatal injuries if blocked.

EXAIR Model 1210 Soft Grip Safety Air Gun

EXAIR’s Soft Grip Safety Air Gun has a durable cast aluminum body that is best suited for rugged industrial use. The ergonomic design has a larger trigger for easy operation and a convenient hanger hook for easy storage. Chip Shields for worker safety are available. Extension pipes and stay set hoses for hard to reach areas are also available.

The inefficient use of compressed air for blow-off applications may create problems due to noise level. High noise levels are a common problem for many plants. Compressed air noise often exceeds OSHA noise level exposure requirements, resulting in close proximity.

Air can also be dangerous when the outlet pressure of a hole, hose or copper tube is higher than 30 PSOG (2 BAR). In the event the opening is blocked by a hand or other body part, air may enter the bloodstream through the skin, resulting i a serious injury.

EXAIR Safety Air Guns use our engineered air nozzles which meet or exceed OSHA Standard 29 CFR – 1910.95 (a) Maximum Allowable Noise Exposure and also OSHA Standard 29CFR 1910.242 (b) Harmful Dead End Pressure.

If you need help choosing the right Safety Air Gun and Engineer Air Nozzle please contact any of our qualified Application Engineers.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

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
Visit us on the Web
Follow me on Twitter