Increased Temps = Time For A Cabinet Cooler

This past Monday, we kicked off the start to the new Spring season, which means warmer temperatures are in the forecast. Here in Cincinnati, we are expecting temps in the low 40’s up to the high 60’s. We’ve written a couple blogs in the past few weeks about the changes in temps and weather and the proverbial “spring cleaning” and the use of our Vacuum Systems for industrial cleanup.

Another area of concern relating to the increased temps is the overheating and contamination of electrical control panels in industrial environments. As the temperatures go up, many companies are looking for a fast solution and will open the doors on the panel and use a fan to blow air across the sensitive controls. While this method does provide some cooling and seems like a quick fix, you are also introducing dirty, potentially humid air into the enclosure which can result in failures and lost production.  Not to mention, this is an OSHA violation which can lead to potential injury to operators  and/or costly fines.

What seems like a simple fix is actually a BAD idea!

EXAIR’s Cabinet Coolers are a reliable, maintenance free way to keep electrical enclosures cool, dry and clean. The Cabinet Coolers are compressed air operated, with cooling capacities ranging from 275 Btu/hr. up to our largest Dual System of 5,600 Btu/hr. The units discharge the cold air into the cabinet at a slight positive pressure which expels the hot, dirty air, leaving only the cool, clean, dry air from the system. Systems are available for continuous operation, maintaining a 45% relative humidity on a completely sealed cabinet, ensuring no condensation develops inside the cabinet. Our Thermostat Controlled Systems are available in 120VAC, 240VAC or 24VDC, providing a more economical operation by only using compressed air when needed to reach the desired temperature set point. Our thermostats are preset at the factory to 95°F but are adjustable to meet your specific temperature requirement.

How the EXAIR Cabinet Cooler System Works

In order to properly recommend a unit, we need to know the internal heat load of the cabinet or watt loss of the controls inside. We realize this information is sometimes not readily available, so to help simplify the process, we have a Sizing Guide available, which provides the pertinent information requited to calculate the current load. Of course, you can always give us a call and an application engineer can help you over the phone as well.

Cabinet Cooler Sizing Guide

 

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Not a Fan of Fans Because Rising Air Temp Will Kill Your Electronics

Using a fan is a popular method for machine builders to provide cooling for an electrical enclosure.  The electrical panel stays cool for machine acceptance at the factory, and possibly for even the first 6-8 months of operation and then one day, there is a problem, and the machine shuts down due to an over heated component within the panel. This leads to opening up the panel, possibly placing an external fan, and operation of the machine in an unsafe condition, to meet the daily production needs.  What has led to this situation?  Summertime!

To better understand the situation, let’s review the heat formula.  The total heat content of air consists of the sensible and latent heat factors. Latent heat is the heat that is required to change the state of a material, say from liquid to solid.  Water to ice is an easy way to understand this type of heat.  When heat is removed from water at 32°F it turns to ice at 32°F.  There is no temperature change, but heat has been removed. Sensible heat is dry heat, it is a result in change of temperature, but not change in state or moisture.  For fan cooling, the air and moisture only change temperature and not state, we can focus on the sensible heat portion.

In English units:  Q = Cp x ρ x q x ΔT x 60 min/hr

And for air:

Q –  is the sensible heat flow in BTU/hr

Cp – is the specific heat in BTU/lb °F – 0.2388 BTU/lb °F

ρ – is the air density at standard conditions – 0.075 lb/ft3

q – is measured air flow in ft3/min – CFM

ΔT – is the temperature difference in °F – Final Air Temperature – Starting Air Temperature

Plugging in the constant values, gives us:

Q = 1.0746 x CFM x ΔT

It is common to chart the above formula for various ΔT values, plotting Q vs. CFM values on a dual logarithmic scale, as shown below-

BTU-CFMGraph4

As an example, for an internal heat load of 1300 BTU/hr, to ensure that the temperature rise (from ambient) in the cabinet does not exceed 20°F, 60.5 CFM of air flow is required (the red line above).  A fan with this CFM rating is specified and installed in the panel.

This works  when the ambient temperature is a comfortable 75°F, in a climate controlled factory, or the cooler months of the year.  The problem occurs when the ambient temperature increases to 95°, 100°, or even 105°F,  not uncommon in the summer, and in plants that create large amount of heat, like metal production, and near boiler systems and furnaces.  Under these conditions, the fan will still maintain the 20°F difference, but the internal temperature of the cabinet will rise to 115°-125°F, temperatures where electrical components start to fail or shut down.  The solution to this issue?  Lower the Starting Air Temperature.

The EXAIR Cabinet Cooler Systems use our Vortex Tube technology to take compressed air and provide a cold flow of air that enters the enclosure at 5o°F less than the compressed air temperature.  With a compressed air temperature of 70°F, common for industrial compressed air systems, the Cabinet Cooler will deliver cold air at 20°F.  Again using the chart above, flowing just 20 SCFM of this air will absorb the 1300 BTU/hr of heat (the green line), and result in an internal air temperature 80°F no matter the ambient air temperature.  The electronics in this enclosure will run trouble free, for a long time. This ambient air temperature problem is also true of air-to-air heat exchangers, as the ambient air temperature rises the ability to remove heat diminishes.

Another consideration, the fan system is bringing in air from the surroundings, which is hot and dirty, passing it through a filter (which gets clogged, reduces air flow, and needs to be replaced.) The Cabinet Cooler System, includes an automatic drain filter separator, which filters the compressed air to be free of dirt, dust and moisture. The air entering the enclosure is cool, dry and fee of dust and debris.

ETC CC

NEMA 4 Cabinet Cooler System with Optional Electronic Temperature Control

To discuss your application and how the EXAIR Cabinet Cooler System can be a benefit at your facility, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Will It Spray?

Video showing the intended use of EXAIR Atomizing Nozzles, illustrated with a green spray pattern.

 

One of the common questions we receive with regards to our Atomizing Spray Nozzles, is whether they will spray a specific liquid.  Most of the time this is a simple answer, found by referencing the viscosity of the liquid and the viscosity range of the specific atomizing nozzle in question.  But, sometimes the viscosity of a fluid isn’t readily available and the best path forward is testing of the specific fluid or application.

Such was the case with the videos above and below.  This application was to spray a specific mixture comprised of catnip biomass onto materials as they pass along a conveyor.  There was no specific flow rate required, we simply needed to spray a specific width at a specific distance away from the product.

The video above shows the desired spray pattern from the nozzles, something with a wide angle and flatpattern, and the video below shows the most suitable solution we found in testing at EXAIR.

The suitable nozzle in this application was our model AD2010SS, an internal mix nozzle with deflected flat fan spraying pattern and a patented technology to prevent liquid flow after compressed air to the nozzle is turned off.  This nozzle provided the right solution for this application, and shipped from stock on the same day we received the order.

Fast forward a few weeks and this same application found benefit from an Electronic Flow Controller (EFC) model 9057.  The EFC allows for sensor-based control of compressed air flow, and thereby control of liquid flow to the AD2010SS nozzles.  This prevents operation of the nozzles when there is no need to spray the liquid.

The discussion, testing, and implementation of this solution are an excellent example of the engineering support available behind EXAIR products.  We really do help our customers find solutions, and if there is an unknown in an application we’re willing to find the answers together.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

EXAIR Cabinet Cooler System Meets High Demands Of Sea Duty

I joined the Navy, right after high school, to get out of Ohio, see the world, and never come back. “My recruiter said” (if you are considering military service, those can be famous last words, just so you know) that I would be a good candidate for Nuclear Power School, so I took the test. As a math & science nerd scholar, I qualified for admission easily.  About halfway through Nuke School, I volunteered for submarines.  My decision was based in no small part on the sea stories of our instructors, the strong reputation of better food, and my deep appreciation for the movie “Operation Petticoat.”

Upon graduation, I was assigned to a new construction Trident submarine.  I did not see the world…I saw the Electric Boat shipyard in Groton, Connecticut, and Naval Submarine Base King’s Bay, Georgia.  Hilarity occasionally ensued, but never in the context of that movie I so adored.  I moved back to Ohio (on purpose) soon after my enlistment was up.  The food WAS good…I can unreservedly vouch for that.

In the new construction environment of the shipyard, I became quite familiar, and developed a deep respect for, the high level of attention paid to the materials and workmanship that a seagoing vessel demanded…not to mention, one with a nuclear reactor on board.  Reliability and durability are obviously key factors.

I had the pleasure recently of assisting an electrical contractor who was looking for a cooling solution for a new Variable Frequency Drive enclosure installation on a cement barge.  The ship’s engineer (a Navy veteran himself) had told the contractor that his priorities were reliability, durability, and dust exclusion.  He couldn’t have made a better case for an EXAIR Cabinet Cooling System.

Based on the specified heat load of the VFD, the size of the enclosure, and its location, a Model 4380 Thermostat Controlled NEMA 12 Cabinet Cooler System, rated at 5,600 Btu/hr, was specified.  This equipment is internal to the ship; had it been exposed to the elements, a NEMA 4X system would have been presented.

Up to 2,800 Btu/hr cooling capacity with a single Cabinet Cooler System (left) or as much as 5,600 Btu/hr with a Dual system (right.)

EXAIR Cabinet Cooler Systems have no moving parts to wear, no electric motor to burn out, and no heat transfer surfaces (like a refrigerant-based unit’s fins & tubes) to foul.  Once it’s properly installed on a sealed enclosure, the internal components never see anything but cold, clean air.

If you have a need to protect an electrical enclosure in aggressive environment, give me a call.  With a wide range of Cabinet Cooler Systems to meet a variety of needs, we’ve got the one you’re looking for, in stock and ready to ship.

Russ Bowman
Application Engineer
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Slick Application for a Super Air Knife

A few weeks back I worked with a customer on an unusual application for one of our Air Knives. The company runs a camp, located in the North-Central part of the United States, complete with their own ski hill for skiing, snowboarding or tubing. They use a conveyor belt ski lift where the skier or snowboarder will stand on the belt and be transported back to the top of the hill for another run. They were starting to see some safety issues arise when the mat would get wet and freeze, causing the skiers to slip and fall back.

Photo of the ski belt conveyor

In an effort to remedy the situation, the installed a brush to try and help remove some of the snow and ice from the belt and while this helped a little, there was still moisture on the belt that would re-freeze. To aid in the drying process, they tried to use a floor blower aimed at the belt but the turbulent airflow seemed to “push” the water around rather than wipe it clean and dry. Out of ideas, they found EXAIR while doing an internet search and decided to give us call for assistance.

Further reviewing the details of the application, I recommended our 30″ Stainless Steel Super Air Knife for the application. The Super Air Knife provides an high velocity, laminar sheet of air across the length of the knife. The laminar flow from the air knife, would assure an even drying effect across the belt, rather than the turbulent flow from the blower. The stainless steel construction of the knife would hold up to the potentially harsh environmental conditions as well.

Super Air Knife available in aluminum, 303ss, or 316ss construction in lengths from 3″ up to 108″.

After some correspondence back and forth regarding air requirements and installation recommendations, the customer was able to source a rental compressor and ordered the 30″ Super Air Knife to test under our Unconditional 30 Day Guarantee. After a few weeks of testing, they were able to effectively dry the belt to an acceptable level, increasing the overall safety for their guests.

30″ SS Super Air Knife mounted under the belt on the “return” side.

 

Clever installation allowed for easy angle adjustment to ensure the airflow contacted the belt for optimal blowoff/drying.

EXAIR offers the quietest (69 dBA at 80 PSIG) and longest (up to 108″) Air Knives on the market today and we stock them in the most materials (aluminum, 303SS, 316Ss and PVDF) to best suit your application. To see how you might be able to utilize an Air Knife in your unique application, give us a call at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

 

 

Troubleshooting Vortex Tube Performance

image-2

This Vortex Tube was not operating properly when initially connected to compressed air

One of the fun parts of Application Engineering at EXAIR is explaining the operation of Vortex Tubes to our customers.  Sometimes they’re described as a “reverse tornado” inside of a tube, spinning a pressurized airstream and converting it into a hot and cold flow.  Other times we describe it through the generation of two vortices with differing diameters, and the difference in diameters results in one vortex shedding energy in the form of heat.

But, no matter the way we explain their operation, we always stress the importance of proper compressed air plumbing.  If the compressed air piping/hoses/connections are not properly sized, performance problems can arise.  (This is true for any compressed air driven device.)

This fundamental came to light when working with one of our customers recently.  They were using a medium sized Vortex Tube to provide spot cooling in an enclosed space, but were not seeing the flow and temperature drop they knew to be possible with an EXAIR Vortex Tube.  And, after looking at installation photos of the application, the root cause was quickly spotted.

image-2-with-arrow

The red arrow in the bottom right corner of this image shows the beginnings of a reduction in compressed air supply.

I noticed what looked to be a very small hose connected to the inlet of the Vortex Tube in the image above.

image-1-with-circle

In this additional image, the small compressed air line is in full view. This was the root cause for performance problems in this application.

After further inspection of another photo, the small diameter tube was in full view.  This small hose serves as a restriction to compressed air flow, which in turn limits both flow and operating pressure of the downstream devices.  What that meant for this application, was poor performance from the Vortex Tube, all stemming from this reduction in piping size.

When looking to find the root cause of a performance issue with a compressed air driven unit, things aren’t always as easy as they were with this application.  A visual inspection is always a good idea, but if everything looks correct, here is a list of troubleshooting steps to consider:

  1. Check for quick-disconnects in the plumbing system.  Quick-disconnects are great from an operator’s perspective, but they can wreak havoc on compressed air flows due to small inside diameters and air volume restriction.
  2. Determine the operating pressure at the device.  This is imperative.  In order to make proper decisions to correct the performance concern, good information is required.  Knowing what is happening at the device is crucial for proper understanding.  There may be 100 PSIG at the main compressed air line, but only 60 PSIG at the device due to plumbing problems. A pressure gauge at the inlet of the compressed air product can provide this information.
  3. Check that the compressed air system has enough volume to properly supply the device.  A compressed air driven unit without the correct volume of compressed air is just as bad as having a lack of pressure.
  4. Check for leaks.  The US Department of Energy estimates that 20-30% of compressor output in industrial facilities is lost as leaks.  If your system and devices aren’t operating as they’re supposed to, check for leaks.  They may be contributing to the poor performance.  (Don’t know where your leaks are coming from?  Use our Ultrasonic Leak Detector!)

Fortunately for this customer, after improving the size of this tubing performance was on par with our published specifications and this customer was back in operation.  If you have a question about how to improve the utilization of the compressed air devices in your application, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

EXAIR Super Air Knives Can Make Everything Better…Even Popcorn!

You know the drill.  In almost any container of popcorn…whether it’s a movie theater bucket, a microwave bag, a stovetop pan (if you’re old school,) or a campfire popper (if you camp with class)…there’s always going to be some un-popped kernels.  And if you don’t pay particular attention to them, they might just activate your dental plan.

This is, unfortunately, an unavoidable inconvenience when dealing with freshly popped popcorn.  For a company that makes pre-packaged popcorn-based snacks, though, un-popped kernels are a real quality issue.  I just had the pleasure of helping a caller with this very issue: although they had a sifter device in place that took care of an awful lot of un-popped kernels, they still had enough getting through to merit a closer look.  Since the popcorn already passed through the sifter on a conveyor, the idea was to “float” the popped kernels across a short break in the conveyor, and let the un-popped kernels fall through.

After a short discussion of their needs, I recommended a Model 110224 24″ Aluminum Super Air Knife Kit. By using the Pressure Regulator (included with the kit) to dial in the air flow, they’re able to keep the popped deliciousness moving on for packaging, and let the dental hazards to fall through, where they’re sent back for another attempt at proper popping. So, they’re not only improving the quality of their product, they’re doing everything possible to make sure no kernel goes un-popped.

Super Air Knife Kits include a Shim Set, Filter Separator, and Pressure Regulator…everything you need to solve your application!

At EXAIR, we’re all about safety when it comes to compressed air use in industrial and commercial settings.  Now one of our products is helping protect peoples’ teeth while they’re eating popcorn snacks!  If you’d like to talk about how an EXAIR Intelligent Compressed Air Product might be able to make things better for you, give me a call.

Russ Bowman
Application Engineer
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