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

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
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Hazardous Locations need Cabinet Cooling too!

Hazardous Locations are a tricky opponent for electrical panels and controls. To safely be in a HAZLOC they either have to be rated for that Environment or they need to be enclosed in a Cabinet that is purged and pressurized to keep any explosive gases, fumes, or dusts out of the Cabinet. This is no new thing, however as the Industrial revolution 4.0 continues to grow and progress products are continually being added to HAZLOC areas. For example, robotic controls, analyzers, motors and switch gears now use electronic accessories to meet the needs for, speed, process control and energy efficiency, which often renders the equipment unsuitable for use in hazardous locations.  While the demand for these new devices continues to grow, not all of these items are able to be made intrinsically safe. And the items that are not will need to be enclosed in a cabinet where heat will build and you need to manage that heat load while retaining the positive pressure a purge and pressurization is putting on the panel.
EXAIR HazLoc Cabinet Cooler Systems are rated for Class I Div 1 & 2, Class II Div 1 & 2, and Class III environments.
First, we need to know what Class, Division, Group and Temp Code your area falls in. Area Classification Methods  The NFPA (National Fire Protection Association) establishes area classifications using three factors. Identified as Classes, Groups and Divisions, these factors are combined to define conditions of specific areas. Class Ratings – Classes are used to define the explosive or ignitable substances that are present in the atmosphere. Class I – Flammable gases or liquid vapor. Class II – Ignitable metal, carbon or organic dusts. Class III – Ignitable fibrous materials. Division Ratings – Divisions are used to define the degree of hazard by determining the explosive or ignitable substance’s expected concentration in the atmosphere. Division 1 – Contains substances under normal conditions Division 2 – Contains substances under abnormal conditions Group RatingsGroups are used to define substances by rating their explosive or ignitable nature, in relation to other known substances. TYPICAL CLASS I SUBSTANCES Group A – Acetylene Group B – Hydrogen or > 30% Hydrogen by Volume Group C – Ethyl Ether & Ethylene Group D – Acetone, Ammonia, Benzene & Gasoline TYPICAL CLASS II SUBSTANCES Group E – Aluminum, Magnesium & Alloys Group F – Carbon, Coke & Coal Group G – Flour, Grain, Wood, Plastic & Chemicals Temperature Class – A Temperature Class is a term that is allocated within a hazardous area or zone to instruments and equipment. The classification or rating signifies the levels of thermal energy allowed in a particular area or produced by specific equipment. EXAIR products are Able to be used in locations at or lower than T3C. EXAIR Cabinet Cooler Systems are available, from stock, to suit most any electric/electronic panel heat protection need:
  • Cooling capacities from 275 to 5,600 Btu/hr. Call me if your heat load is outside this range…we can look at customized solutions too.
  • NEMA 12 (IP54), 4, or 4X (IP66) ratings.
  • Thermostat Control – Standard, or Electronic Temperature Control.
  • Non-Hazardous Purge for contaminant exclusion on less-than-ideally sealed enclosures.
  • High Temperature models for ambient temperatures from 125°F (52°C) to 200°F (93°C).
  • Side Mount Kits when space is limited above the panel.
  • 316SS construction for particularly aggressive environments.
  • UL Classified for hazardous locations,
    • Class 1 Div 1, Groups A,B,C and D
    • Class 2 Div 1, Groups E,F, and G
    • Class 3
    • Temp T3C
When choosing products for use in classified areas, it’s critical to ensure safety through compliance, and the HazLoc Cabinet Cooler Systems allow you to do that, with simplicity and reliability.  If you’d like to discuss an enclosure cooling application, in or out of a classified area, give us a call. Jordan Shouse Application Engineer Send me an Email Find us on the Web  Like us on Facebook Twitter: @EXAIR_JS

Cabinet Coolers: How to Determine Heat Loads

As summer continues, electrical panels will continue to overheat and cause problems within your process lines.  Freon-based coolers can be less effective in higher ambient conditions; and opening the electrical panels to have a fan blow inside creates a dangerous hazard.  The electrical industry states that for every 10oC rise above the operational temperature, the life of an electrical component is cut in half.  To reduce loss in production and premature equipment failures, it is important to keep electrical components cool.  The EXAIR Cabinet Cooler Systems are designed to do just that. 

From right to left: Small NEMA 12, Large NEMA 12, Large NEMA 4X

To find the correct type and size, we need some information about your electrical panel.  EXAIR makes it easy with the Cabinet Cooler Sizing Guide.  This sheet goes over the important details to find heat loads, proper NEMA type, and options for easy installation.  With a filled-out form, we can make sure that the correct model is recommended.  First, we have to start with the surface area of the electrical panel.  From here, we can do some heat load calculations to compare it with the proper cooling capacity. 

To properly reduce the temperature internally, we need to calculate how much heat is being generated.  Heat loads come from four main areas; internal, external, fan, and solar.  From these four, we can add them together to get the total heat load.  So, on the hottest day of the hottest month, the EXAIR Cabinet Cooler System will still keep your electronics cool.  Here are some methods to find the information needed for heat load calculations.

Internal Heat Load:  The internal load is the heat generated from inside the electrical panel.  This heat is produced from the inefficiencies of electrical devices.  There are two ways that we can figure out the internal heat load.

Step A: The simplest way is by hanging a piece of metal like a washer inside the panel for about 15 minutes.  We can get an average temperature inside.  In the sizing guide, you can mark the temperature next to “Internal temperature now”.  To calculate the heat load, we will need the external temperature at the same time you measured the piece of metal.  This temperature difference can determine the internal heat load per surface area of the panel.  See the chart below.

Step B:  if you know the electrical components inside that generate heat, a list can be made with volt/amp ratings, or watts.  This is very useful for new panels.  The major devices would be VFD (Variable Frequency Drives), power supplies, UPS, transformers, thyristors, etc.  We can calculate the inefficiency of the electrical components which will give us the internal heat load.

External Heat Load:  To keep the electronics cool on the hottest day, we will need to know the highest external temperature that the panel will see.  This can include the temperature that is near an oven.  This can be marked in the Max External Air Temperature Possible.  We can compare this to the Max Internal Air Temperature Desired.  Most electrical components are designed to operate at 95oF (35oC).   With the same chart as above, you can use the temperature difference to determine the external heat load per surface area of the panel.

Panel Fans:  To control the environment inside the electrical panels, we need to block all openings and vents.  And this will include removing panel fans if they are installed.  The Cabinet Cooler System will blow dry cold air to push out the hot humid air from the electrical panel back through the Cabinet Cooler.  Since we are removing a “poor” cooling device, we still need to add this to the heat that is being removed.  You can either give the diameter of the fan or the flow of the fan. 

Solar Heat Load:  The solar heat is only needed if the panel is located outside without cover and exposed to sunlight.  For this type of heat load, we will need to know the color of the electrical panel.  Lighter colors will not absorb as much heat as darker colors.

Because there is so much information that is critical for proper sizing, EXAIR also created a Cabinet Cooler System Calculator to give you a good recommendation to keep your electronics cool. I gave some examples above on how to find the heat loads.  Electrical shutdowns are expensive and annoying.  If you have interruptions from high internal temperatures, EXAIR Cabinet Coolers are a great solution.  They can be installed quickly and easily.  With no moving parts or costly preventative maintenance needed, they can run for decades in keeping your electronics cool.  For our U.S. and Canadian customers, you will receive an AC Sensor for free, a $65.00 value, as a promotional item from now until the end of August 2022 with qualified purchases.  How can you not give them a try?  If you have any questions about Cabinet Coolers or the Sizing Guide, you can contact an Application Engineer at EXAIR.  We will be happy to help.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb