Battling Heat Transfer

If you haven’t read many of my blogs then this may be a surprise. I like to use videos to embellish the typed word. I find this is an effective way and often gives better understanding when available.  Today’s discussion is nothing short of benefiting from a video.

We’ve shared before that there are three types of heat transfer, more if you go into sub-categories of each. These types are Convection,  Conduction, and Radiation. If you want a better understanding of those, feel free to check out Russ Bowman’s blog here.  Thanks to the US Navy’s nuclear power school, he is definitely one of the heat transfer experts at EXAIR.  If you are a visual learner like myself, check out the video below.

The Application Engineering team at EXAIR handles any call where customers may not understand what EXAIR product is best suited for their application. A good number of these applications revolve around cooling down a part, area, electrical cabinet, or preventing heat from entering those areas.  Understanding what type of heat transfer we are going to be combating is often helpful for us to best select an engineered solution for your needs.

Other variables that are helpful to know are:

Part / cabinet dimensions
Material of construction
External ambient temperature
If a cabinet, the internal air temperature
Maximum ambient temperature
Desired temperature
Amount of time available
Area to work with / installation area

Understanding several of these variables will often help us determine if we need to look more towards a spot cooler that is based on the vortex tube or if we can use the entrained ambient air to help mitigate the heat transfer you are seeing.

If you would like to discuss cooling your part, electrical cabinet, or processes, EXAIR is available. Or if you want help trying to determine the best product for your process contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Video Source: Heat Transfer: Crash Course Engineering #14, Aug 23, 2018 – via CrashCourse – Youtube – https://www.youtube.com/watch?v=YK7G6l_K6sA

Super Air Amplifiers vs. Electric Fans

EXAIR’s product offerings contain many products that can be used for cooling. The focus of this blog will be Super Air Amplifiers. These often times get placed in a head to head competition with an electric fan. The best part, they easily come out on top.

Our own Tyler Daniel produced a great video showcasing how efficient it is to cool a part using the Super Air Amplifier rather than a fan.

When looking at the benefits other than performance and rate of cooling due to air entrainment, many customers prefer the Super Air Amplifier due to the fact there are no moving parts. This comes into play when cooling within in a hard to reach area or within a harsh process is needed.  Placing an electric motor with a blade held on by fasteners may not be desirable from a maintenance standpoint. The Super Air Amplifiers do not require electricity, meaning there is not a motor or bearings that would need to be replaced or inspected.

Another benefit is the small footprint of the Super Air Amplifier. This can also be seen within the video above where the Air Amplifier is shown is able to produce 341 SCFM (9,650 SLPM) in amplified airflow.  This gives the ability to place a small unit inside of a chamber that needs large volumes of air flowed through it.  For instance, a rotomolded part that has a large chamber and it needs surfaces to be cooled in order for the part to hold its shape from the mold rather than warp.  This can also be coupled with the fact that a Super Air Amplifier can be ducted on either the suction or discharge side in order to retrieve cool air or move the warm air out of the area.

Speaking of warm, the Super Air Amplifiers are also manufactured to withstand up to 275°F (135°C) from stock.  Stainless Steel and High-temperature models go well beyond that temp, as seen above. Custom-designed (flanges and different materials are common) versions are also available in short lead-times.

If you would like to discuss the benefits to a Super Air Amplifier further, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

The Makeup of Earth’s Air

Most people know that oxygen, makes up about 20% of the earth’s atmosphere at sea level, and that almost all the rest is nitrogen. But did you know there’s an impressive list of other gases in the air we breathe

whats in air
Reference: CRC Handbook of Chemistry and Physics, edited by David R. Lide, 1997.

We can consider, for practical purposes, that air is made up of five gases: nitrogen, oxygen, argon, carbon dioxide, and water vapor. But because water vapor is a variable, this table omits it, water vapor generally makes up 1-3% of atmospheric air, by volume, and can be as high as 5%.  Which means that, even on a ‘dry’ day, it pushes argon out of third place!

There are numerous reasons why the volumetric concentrations of these gases are important.  If oxygen level drops in the air we’re breathing, human activity is impaired.  Exhaustion without physical exertion will occur at 12-15%.  Your lips turn blue at 10%.  Exposure to oxygen levels of 8% or below are fatal within minutes.

But here at EXAIR we care about how compressed air can be used efficiently to better your process! 

Any of our products are capable of discharging a fluid, but they’re specifically designed for use with compressed air – in basic grade school science terms, they convert the potential energy of air under compression into kinetic energy in such a way as to entrain a large amount of air from the surrounding environment.  This is important to consider for a couple of reasons:

  • Anything that’s in your compressed air supply is going to get on the part you’re blowing off with that Super Air Nozzle, the material you’re conveying with that Line Vac, or the electronics you’re cooling with that Cabinet Cooler System.  That includes water…which can condense from the water vapor at several points along the way from your compressor’s intake, through its filtration and drying systems, to the discharge from the product itself.
  • Sometimes, a user is interested in blowing a purge gas (commonly nitrogen or argon) –  but unless it’s in a isolated environment (like a closed chamber) purged with the same gas, most of the developed flow will simply be room air.

Another consideration of air make up involves EXAIR Gen4 Static Eliminators.  They work on the Corona discharge principle: a high voltage is applied to a sharp point, and any gas in the vicinity of that point is subject to ionization – loss or gain of electrons in their molecules’ outer valences, resulting in a charged particle.  The charge is positive if they lose an electron, and negative if they gain one.  Of the two gases that make up almost all of our air, oxygen has the lowest ionization energy in its outer valence, making it the easier to ionize than nitrogen.  You can certainly supply a Gen4 Static Eliminator with pure nitrogen if you wish, but the static dissipation rate may be lesser.

If you want to learn more about the compressed air or any of our point of use compressed air products, you can contact an Application Engineer.  We will be happy to help you.

Jordan Shouse
Application Engineer

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Air photo courtesy of Barney Moss Creative Commons License

Cabinet Coolers Material Selection Focus: 316 Stainless Steel

Industrial environments call for equipment to be constructed of many different materials in order to stand the test of time and to meet standards set by governing agencies. Within certain environments, 316 stainless steel rules the world and there is due cause for it. In given areas, there may be chemical incompatibilities, temperature limits, or even material incompatibilities between parts within a process and the process itself.  This is why the EXAIR Cabinet Cooler Systems are available in 316 stainless steel.

The NEMA Type 4X Cabinet Cooler Systems are standard in 303 stainless steel while 316 stainless steel is also available from stock and can meet or exceed the standards set forth by NEMA Type 4X environments to stand the test of time whether it be chemical/caustic washdowns that generate the need, product material compatibility, or due to being outside.  These systems are offered in both thermostatically controlled with choice of 120 VAC, 230 VAC, or 24 VDC solenoid valve or continuous operation and can all ship same-day on orders received by 3 PM ET for domestic orders.

We also offer Hazardous Location NEMA Type 4X Cabinet Cooler Systems in both 303 and 316 stainless steel to cover even more stringent classified areas that demand UL Classified certifications.   These meet certifications for Class I Div 1, Groups A, B, C and D, Class II Div 1, Groups E, F and G, as well as all Class III environments.  These systems are also offered in the same thermostat control voltages as well as a continuous operation.

The point is, if you have an overheating control panel or electrical panel, we will have a solution that can keep your production running, all you have to do is contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF