Hazardous Location AND Overheating Electronics? We Have You Covered!

Here in Ohio, we like to think we know a lot about the weather. Did you know there are more than 4 seasons? Heck, we have at least two Winters, and then a Pre-Summer, Spring, Summer, Heat is still coming – make it stop season, and Fall. Don’t forget the construction season where the lovely orange cones and barrels bloom on every major roadway, and then we also like to throw in brood weeks for the cicadas every now and then. Yeah, we get a full gambit of weather and the past week has brought out some heat. I know this isn’t just Ohio, we get calls from around the globe of atmospheric conditions that have caused issues within control panels. Some of these panels are in areas where the No Smoking sign is more than just a suggestion to better your health.

1 – Dust Explosion

That’s right, there are areas in manufacturing facilities that are governed by the standard due to a variety of conditions resulting in what is known as Hazardous Locations. NFPA and UL have a list of standards breaking these down into separate Classes, Divisions, and Temperature Classes. If you want all the details, the NFPA code is around 908 pages, cover to cover. The Classified UL mark shown below is one way of knowing that a product has been tested to these stringent standards and is okay to use in clearly marked environments.

UL Classified Markings

EXAIR offers Cabinet Cooler Systems that will meet these stringent standards and keep your enclosures cool in order to keep your production up and running. The top three tiers that we meet are:

  • Class I Div 1, Groups A, B, C and D
  • Class II Div 1, Groups E, F and G
  • Class III

The HazLoc Cabinet Cooler Systems are available in 8 different cooling capacities from 1,000 Btu/hr to 5,600 Btu/hr. and are manufactured to work in conjunction with a purged and pressurized control system. As well as with or without thermostatic control.

EXAIR’s Hazarous Location Cabinet Cooler Systems maintain Type NEMA 4/4X Integrity and are CE Compliant.

If you would like help sizing the correct system for your electrical panels, feel free to use the link, or contact an Application Engineer to discuss the applications and get one sized while on the phone with us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Dust explosion 05.jpg, Hans-Peter Scholz, October 7, 2009, retrieved from https://commons.wikimedia.org/wiki/File:Dust_explosion_05.jpg

Round and Round They Go…. Rotary Compressors: How They Work

Positive-displacement and dynamic displacement compressors are the two high level principles for the generation of compressed air or gas. Positive displacement types are the most common found in industrial facilities. These units draw ambient air into a chamber which it seals off and then works to compress and squeeze it down into a smaller volume. The air is then discharged into the outlet system of the compressor. Out of the many types of positive displacement compressors, today we are going to discuss the rotary style positive displacement air compressors.

1 – Simplified Rotary Vane Compressor



These are available in both lubricant-free as well as lubricant-injected versions. The main function of the compressor is the same, both have two inter-meshing rotors what pull air into the inlet port and then after the rotational processing of the compressor the air is discharged through a discharge port. The in between of the ports is where the important information lies. The air after being sucked into the inlet gets pulled in between two lobes and the stator. As the air is being trapped the space between the lobes becomes increasingly smaller, thus increasing the pressure of the air transferring it to the discharge port.

The lubricated versions will often help to dissipate the heat that is created as the air is being compressed. This lubricant is then possible to transfer into the compressed air stream and must be removed before a point of use product if lubricant-free air is needed for the process. These compressors rank amongst the lower efficiencies in the positive displacement air compressors.

If you are visual learner, feel free to take a few minutes for the video below.

2 – Rotary Compressor Operation


If you would like to discuss the way to get the most out of your compressor, no matter the type, contact an Application Engineer and let us help you determine the most efficient way to use the air effectively.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Rotary vane.png – R. Castelnuovo, 10/20/2005 – retrieve from https://commons.wikimedia.org/wiki/File:Rotary_vane.png

2 – Rotary compressor operation – HVACRinfo.com – 8/1/2016 – retrieved from https://www.youtube.com/watch?v=fxDEK3Ymx30

Choosing Max Refrigeration Or Max Cold Temp Vortex Tubes

Vortex Tubes have been studied for over 90 years. These “phenoms of physics” and the theory behind them have been discussed on this blog before. But, when it comes to the practical use of a Vortex Tube it is good to discuss how to correctly select the model that may be needed in your application. The reason being, there are different flow rates and an option for maximum refrigeration or maximum cold temperature.

The tendency is to say, well I need to cool this down as far as possible so I need the coldest air possible, give me the maximum cold temperature. More times than not, the maximum cold temperature model is not the best solution for your application because maximum cooling power and maximum cold temperature are not the same thing.  A maximum cold temperature Vortex Tube is best for spot cooling processes that require greater than 80F temperature drop covering a small area – spot cooling at its finest. Theis very cold air is delivered in a low volume. A maximum cooling power Vortex Tube is the best mix of cold temperature and volume of flow. This cold air (50F-80F temperature drop) is delivered at higher volumes which has the ability to remove more heat from certain processes. If you do not know which is bets for your application, follow these next steps. 

The first step, is to call, chat, or email an Application Engineer so that we can best outfit your application and describe the implementation of the Vortex Tube or spot cooling product for you. You may also want to try and take some initial readings of temperatures. In a perfect world you would be able to supply all of the following information to us, but recognizing how imperfect it all is…some of this information could go a long way toward a solution. The temperatures that would help to determine how much cooling is going to be needed are listed below:

Part temperature:
Part dimensions:
Part material:
Ambient environment temperature:
Compressed air temperature:
Compressed air line size:
Amount of time desired to cool the part:
Lastly desired temperature:

With these bits of information, we can use standard cooling equations to determine what temperature of cold air stream and volume of air is needed in order to produce the cooling and your desired outcome. To give an idea of some of the math we have used, check out this handy educational video of how Newton’s law of cooling was used to calculate the amount of time it takes to cool down a room temp beverage in an ice cold refrigerator. 

If you would like to discuss a cooling application, heating application, or any point of use compressed air application, contact an Application Engineer today.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – ThinkWellVids – Newton’s Law of Cooling – Feb. 27, 2014 – retrieved from https://www.youtube.com/watch?v=y8X7AoK0-PA

Centrifugal Air Compressors: How Do They Work?

Centrifugal air compressors are one example of dynamic style air compressors. The dynamic type of compressors have a continuous flow of air that has its velocity increased in an impeller that is rotating at a higher speed. The kinetic energy of the air is increased due to the increase in velocity and then becomes transformed into pressure energy through the use of a volute chamber, or a diffuser. The volute chamber is a curved funnel that increases in surface are as it approaches the discharge port. This converts the kinetic energy into pressure by allowing the velocity to reduce while the pressure increases. Approximately 1/2 of the energy is developed in the impeller and the other half is developed in the volute chamber or diffuser.

1 – Basic Centrifugal Air Compressor

The most common centrifugal air comppressor has between two and four stages in order to generate pressures up to 150 psig. A water cooled inter-cooler and separator is placed between each stage in order to remove condensation and cool the air down prior to being passed on to the next stage. These compressors still have advantages and some disadvantages. The list below showcases just a few.

Advantages:

  • Lubricant-free air is generated
  • Complete packages up to 1,500 hp
  • Initial costs decrease with increase in compressor size
  • No special foundations or reinforcements needed

Disadvantages:

  • Specialized maintenance requirements
  • Higher initial investment
  • Unloading/waste of air required to drop system pressures

To determine which type of compressor may be best suited for your facility, we suggest to locate and contact a compressor sales company in your geographic area. When it comes to determining the volume of air required to operate the EXAIR products and even some other point of use compressed air applications, EXAIR’s Application Engineers can help you determine the volume you will need to ensure the compressor is sized appropriately. If you would like to discuss any other point of use application, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Dugan, Tim PE – Basic Centrifugal Air Compressor, Compressed Air Best Practices; retrieved from https://www.airbestpractices.com/technology/air-compressors/centrifugal-air-compressor-controls-and-sizing-basics