Refrigerated Air Dryers

Whenever air gets compressed, it reduces the space for the water molecules to remain as a vapor; which causes condensation.  For this, compressed air dryers are an important part of a compressed air system.  They are designed to remove moisture to prevent condensation further downstream in the system.  The three main types of dryers are refrigerated, desiccant, and membrane. For this blog, I will cover the refrigerant-type compressed air dryers.

Compressed air dryers are rated with a dew point rating.  A dew point is the temperature at which the air has a relative humidity of 100%.  Since the air cannot become more saturated with water than 100%RH, water will condense and fall out like “rain”.  You can see this effect during the cool mornings when dew forms on the grass.  Compressed air dryers are designed to reduce the dew point temperature of your compressed air.  For a refrigerant type, they are near the dew point temperature of 38oF (3oC).  Like a refrigerator, they use refrigerant to cool the compressed air.  We cannot go below this temperature as it could form ice inside the dryer.  But, as long as the ambient temperature does not go below 38oF (3oC), liquid water will not be present in the pneumatic system. 

There are two main types of refrigerated air dryers; cycling and non-cycling.  Cycling type refrigerant air dryers will cool a liquid mass, generally a glycol-water mixture, to a set-point and turn off.  The liquid will go through an air-to-liquid heat exchanger to remove the heat from the compressed air.  Referring to the cycling action, when the liquid mass goes above the set point, the refrigeration system will restart and cool the liquid mass again.  The cycling refrigerant air dryers are more expensive, but they are more efficient. 

Non-cycling refrigerant air dryers are more common.  The refrigeration system continues to run through an air-to-air heat exchanger to cool the compressed air.  It is similar to your AC system in your car.  With this type of system, they are more susceptible to the environment, i.e., temperature, elevation, and humidity.  So, adjustments are required for proper installation. 

With both types of refrigerant dryers, the internal compressed air section is very similar.  They will have a filter separator to remove the liquid that is created from the condensation from the cold temperatures.  They also have an additional air-to-air heat exchanger.  This will provide two important features for the refrigerated air dryers.  As the cold air leaves the refrigerant section, it helps to cool the incoming compressed air.  This will make the system more efficient.  And as the hot incoming compressed air helps to warm the cold air leaving the dryer, it will stop the condensation of liquid water on the outside of the pipes.  Like the dew forming on the grass during cool mornings, the same will occur with the compressed air piping system. 

Moisture-laden compressed air can cause issues such as increased wear on the pneumatic tools, the formation of rust in piping and equipment, quality defects in painting processes, and frozen pipes in colder climates.  Regardless of what products you’re using at the point-of-use, a compressed air dryer is undoubtedly a critical component of the compressed air system.  Delivering clean, dry air to your EXAIR Products or other pneumatic devices will help to ensure a long life out of your equipment.  If you wish to discuss more about your compressed air system or how EXAIR can provide a more efficient way to use that compressed air, an Application Engineer will be happy to assist you. 

John Ball, CCASS


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

Photo: Grass morning dew by RuslanSikunovPixabay License

E-Vac Vacuum Generators- For More Than Just Pick and Place

A textbook application for vacuum generators is the ‘pick and place’ function.  With ever increasing automation and robotic cells, more and more opportunities present themselves to utilize the E-Vac Vacuum Generator as a part of the system to ‘pick up’ an object and ‘place’ it in a new position. But the E-Vac’s can be used for many more types of applications.

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In-Line E-Vac

Another popular usage is to hold something in place. One of our customers uses an array of Adjustable E-Vacs to pull a vacuum and hold down various sizes of Styrofoam sheets during a machining operation. The previous system was a 1 hp blower type, and did not offer any flexibility for handling different size sheets. Sheets would slip and produce off quality results. After installing the new design, the system was able to handle any size sheet, and scrap levels went down dramatically.

adjustable_evacs (2)
Adjustable E-Vac

A unique implication that was solved with an E-Vac was to deflate sporting balls.  The customer printed custom logos, and preferred the items to be flat for the printing operation. Using a commercial grade electric shop vac didn’t completely deflate the balls, and motors burned out often.  Using a low vacuum In-Line E-Vac with a quiet Straight Through Muffler, the customer can now quickly and quietly, fully deflate the balls.

Another popular use for the E-Vac is to pull a vacuum for drawing up liquids or gases. A customer that manufactures automotive seats was having issues with the process, where the expanding foam was producing a gas, and the gas would produce pockets and voids in the foam after setting.  The customer used a model 800017 In-Line E-Vac to create a vacuum inside the mold and draw off the gas, eliminating the pockets and the voids in the final product.

Lastly, as I am big fan of recycling, anything and everything, we worked with a customer that recycles the old CRT style of computer monitor  (remember those?) The housing would be sawed in half, so that access to the internal components could be made. Because of the variability in the size and shape of the monitors, the customer was using an adjustable chuck system, which took time to set-up for every monitor, each being a bit different. To speed up the process, an EXAIR In-Line E-Vac and 5″ Suction Cup was implemented, and the monitor held in place by the screen, which was was very consistent in shape from monitor to monitor. This change reduced the set-up time required.

These and other Applications for the E-VACs and all other EXAIR products can be found on the EXAIR website on the Products page, under the Related Info section toward the bottom of each page.

If you have questions regarding E-Vac Vacuum Generators or any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Reversible Drum Vac Empties Sumps For Demolition Company

A demolition company was looking for a way to remove the liquid from sumps and tanks in the industrial buildings they were contracted to provide their service upon. The liquids in question were mainly coolant and oil that had been left behind when the machinery was removed…anything that could be re-used was already gone; this was the “bitter dregs,” as it were.  Since these buildings are about to be demolished, electricity is rarely available.

They had a pumping system that ran off a diesel engine that they COULD take with them, but they ALWAYS had a large mobile air compressor for the pneumatic tools used in other processes in the demolition of the building. Since they had steel drums in abundance, the Reversible Drum Vac Systems sounded very attractive to them, so they got a Model 6295 Deluxe High Lift Reversible Drum Vac System for 55 Gallon Drum to try out.

The High Lift Reversible Drum Vac System converts a drum and dolly into a mobile pumping system.

Now, instead of committing an additional truck (and driver) to getting the diesel engine driven pumping system to the site, they simply move the Reversible Drum Vac pump unit from 55 gallon drum to 55 gallon drum as they’re filled. Once the drums are returned to their facility, they switch the the Reversible Drum Vac to the “empty drum” configuration, and use it to pump the liquid out into their recycling tanks, where they await collection and processing by their waste handling service.  Even when they have to use a number of drums, the High Lift Reversible Drum Vac Systems still streamline the process over the use of the diesel engine pumping system.

If you’d like to find out more about our Industrial Vacuums, or any of our compressed air operated products, give me a call.

Russ Bowman
Application Engineer
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Another “Bucket And Ladder” Operation, Foiled By The Line Vac

Let me start by saying that EXAIR Corporation has nothing against buckets. Or ladders. We use them both here for a variety of tasks, and are very satisfied with them. But when they’re used together…that’s where we’re going to take exception. And we’re not the only ones.

I had the pleasure of speaking to an expert technician with a company that provides world class water recycling equipment & services. They use our Model 140200 2″ NPT Threaded Aluminum Line Vacs to move bentonite clay (an amazingly versatile purification & absorption media) from 50 lb bags into a hopper. It is then dispersed into a holding tank of oily water, where it removes the pollutants and impurities, allowing for clean recycling.  And, since they no longer have to carry it up a ladder and pour it in, it’s also safer and more efficient.

Model 140200 2" NPT Aluminum Threaded Line Vac moves bentonite clay into water recycling tank.
Model 140200 2″ NPT Aluminum Threaded Line Vac moves bentonite clay into water recycling tank.

EXAIR Corporation is committed to being proactive about the way we impact the environment. Our Sustainability Plan details the way we do this in regards to our responsible consumption of resources, our conscientious waste recycling measures, and the comprehensive impact of our products…everything from materials & design, to their efficient usage, to packaging. So, when our products are used in  application geared toward like-minded goals, it’s a win-win-win. For EXAIR, our customers, and the environment.

This is one of many ways that EXAIR’s diverse line of compressed air products are not only making processes more efficient, but making the world a better place through dedication to being “clean and green.” If you’d like to know more, please give me a call.

Russ Bowman
Application Engineer
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