Intelligent Compressed Air: Refrigerant Dryers and How They Work

We’ve seen in recent blogs that Compressed Air Dryers are an important part of a compressed air system, to remove water and moisture to prevent condensation further downstream in the system.  Moisture laden compressed air can cause issues such as increased wear of moving parts due to lubrication removal, formation of rust in piping and equipment, quality defects in painting processes, and frozen pipes in colder climates.  The three main types of dryers are – Refrigerant, Desiccant, and Membrane. For this blog, we will review the basics of the Refrigerant type of dryer.

All atmospheric air that a compressed air system takes in contains water vapor, which is naturally present in the air.  At 75°F and 75% relative humidity, 20 gallons of water will enter a typical 25 hp compressor in a 24 hour period of operation.  When the the air is compressed, the water becomes concentrated and because the air is heated due to the compression, the water remains in vapor form.  Warmer air is able to hold more water vapor, and generally an increase in temperature of 20°F results in a doubling of amount of moisture the air can hold. The problem is that further downstream in the system, the air cools, and the vapor begins to condense into water droplets. To avoid this issue, a dryer is used.

Refrigerated Dryer

Fundamental Schematic of Refrigerant-Type Dryer

Refrigerant Type dryers cool the air to remove the condensed moisture and then the air is reheated and discharged.  When the air leaves the compressor aftercooler and moisture separator (which removes the initial condensed moisture) the air is typically saturated, meaning it cannot hold anymore water vapor.  Any further cooling of the air will cause the moisture to condense and drop out.  The Refrigerant drying process is to cool the air to 35-40°F and then remove the condensed moisture.  The air is then reheated via an air to air heat exchanger (which utilizes the heat of the incoming compressed air) and then discharged.  The dewpoint of the air is 35-40°F which is sufficient for most general industrial plant air applications.  As long as the compressed air stays above the 35-40°F temperature, no further condensation will occur.

The typical advantages of Refrigerated Dryers are-

  1.  – Low initial capital cost
  2.  – Relatively low operating cost
  3.  – Low maintenance costs

If you have questions about getting the most from your compressed air system, or would like to talk about 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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Cabinet Coolers in January?

Dual CC outside

Without putting too much thought into it, one might assume that January would not be Cabinet Cooler season. But actually, our friends in the southern hemisphere (Australia, New Zealand, South Africa, Argentina, Chile and Brazil) are experiencing their summer at the very same time that we in the mid-west of the United States have been having some bone-chilling cold weather blow in from Canada. Our New Zealand distributor told me just the other day that they were having 35°C days with water restrictions and everyone is on fire watch because it is so hot and dry right now.

As uncomfortable as that might be for the folks living there, many must continue their production in the un-air conditioned environments. And in doing so, they have to keep their machines up and running to maintain production. But the controls for those machines are not always so cooperative because the CPU is overheating or the inspection camera is giving out because it is too hot.

Where do they turn?  EXAIR of course. Once our distributor partner assists the customer with sizing and makes recommendation (sometimes with a little help from us). The customer installs the Cabinet Cooler System and has taken care of their overheating problem within the application once and for all.

The reason why I say “once and for all”, is that the Cabinet Cooler Systems have no moving parts and are virtually maintenance-free. There are no filters to constantly change due to dirty factory environments. And best of all, the Cabinet Cooler can continue to operate in the range of 20 years plus.

When you compare the small cost of a Cabinet Cooler System to that of down time, lost production and the cost to repair burnt out controls, it is truly an easy decision to make.

So, back to our friends in the Southern Hemisphere, where hot and dry is the order of the day, consider having an EXAIR Cabinet Cooler for your application today. Contact us in the International Application Engineering / Sales Department or consult our International Distributor Locator to find the distributor near to you.

Neal Raker, International Sales Manager
nealraker@exair.com

Long Super Air Knife Dries Cast Acrylic Sheets

5967985755_91dd48ce36_b

I have a customer who works for a company that produces plain, acrylic sheets which are used to produce various products used in high end bathrooms. Generally, those products are bathtubs, shower surrounds, floor pans, etc.

Our customer produces the flat sheet which is produced by pouring a liquid resin between two glass sheets which is then cured to a solid phase. Once the glass molding material has been stripped away, the edges are finished and the sheet is washed and dried.

The drying part is where EXAIR 84” Long Super Air Knife comes into play. The customer’s sheet is two meters wide and so the 84” Super Air Knife provides a continuous curtain of air across the surface of the acrylic sheet to drive the rinse water off the sides and edges. Once dried, our customer lays a protective sheet of heavy paper between the sheets of acrylic to keep the surfaces from being scratched or otherwise blemished from rubbing during transport.

Prior to moving to the Super Air Knife for this production, the customer was using a series of 40 pieces of a flat, plastic, two inch wide, air nozzle made by a company who specializes in water nozzles. The nozzles themselves were designed to consume 24 SCFM @ 80 PSIG each. The customer had these mounted to a 1” pipe that was hung above the acrylic sheet. The problem was that these nozzles used so much air that they could barely keep 30 PSIG on the header pipe supplying them due to pressure drop in their system and the noise level was up over 90 dB. The result, poor blow off performance. The estimate for their air usage was in the range of 450 SCFM for this project.

After installing the 84” Super Air Knife, the customer was able to finally maintain a reasonable header pressure of 80 PSIG at the inlets to the Super Air Knife which provided for a solid and consistent blowing velocity all the way across the width of the material. The sound level was also able to drop down to a more pleasing 75 dB with implementation of the Super Air Knife. Finally, the air consumption was dropped to a more reasonable 244 SCFM for the 84 inch Super Air Knife. A 46% reduction on air usage.

If you have a wide format type of product that you are trying to cool, dry or blow debris from, consider the Long Super Air Knives. They will provide you with a forceful, even velocity across the full width of your material.

Neal Raker, Application Engineer
nealraker@exair.com

 

Acrylic_Clear_1-4_001 image courtesy of thebaumans. Creative Commons license

Why 5 PSIG Matters

Last week I pointed out the important locations for measuring your compressed air system pressure throughout your compressed air system.   One of the critical points to measure system pressure was before and after each filter.  This leads into another question that I receive every once in a while, “How do I tell when the filter needs to be changed?”  The answer to this is easy, when you see more than a 5 PSIG pressure drop across the filter.  This means that the element within the filter has become clogged with sediment or debris and is restricting the volume available to your downstream products.

Filter

EXAIR 5 micron Auto Drain Filter Separator

 

This can lead to decreased performance, downtime, and even the possibility of passing contaminants through the filter to downstream point of use components.  In order to maintain an optimal performance when using EXAIR filter separators and oil removal filters, monitoring the compressed air pressure before and after the unit is ideal.

Replacement filter elements are readily available from stock, as well as complete rebuild kits for the filter units. Changing the filters out can be done fairly easily and we even offer a video of how to do it.

The life expectancy of a filter element on the compressed air is directly related to the quality of air and the frequency of use, meaning it can vary greatly.  If you tie a new filter onto the end of a compressed air drop that has not been used in years, you may get a surprise by the filter clogging rather quickly.   However, if you maintain your compressor and your piping system properly then the filters should last a long time. Generally we recommend checking your filters every 6 months.

If you have questions about where and why to filter your compressed air contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Video Blog: Effectiveness of Filtering Your Compressed Air

The video below will give a brief demonstration on the importance of point of use filtration in order to remove unwanted material such as water, scale, particulate and oil from your compressed air stream. Point of use or end-use filtration will keep your air clean and your compressed air products running smooth.  If you have any comments or questions, please feel free to contact us.

 

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

EXAIR Static Field Meter, Locating Your Static Problem

Static Meter

Model 7905 Digital Static Meter comes with certification of the accuracy and calibration traceable to NIST (National Institute of Standards and Technology). A hard-shell case and 9 volt battery are also included.

As we finish up 2013 and head into the winter season in the Northern hemisphere, static problems begin to become more prevalent again due to the general lower humidity present in most manufacturing areas.

Some of the resulting symptoms of the static condition are: discharges to personnel, jamming, tearing, discharges to machines and sensors. Finally, discharges within a charged material can also cause blemishes to materials that must have absolute clarity within them. We’ve all been the victim of a nasty static discharge at some point or another. You can have the right tool in using an active static eliminator. But how do you know if you have your static eliminator located in the right position for maximum effectiveness?

That is where the EXAIR Static Meter model 7905 comes into play. This easy to use meter will indicate where the static field(s) are located in their process, how large they are in terms of kV / 1 inch distance from the charged target, and their polarity (+ or -). The meter can make direct readings up to +/- 20 kV at 1 inch distance.

The above pieces of information are handy for knowing where to place static eliminators for any given process. Static cannot be seen directly, and so your best bet for implementing an effective strategy is to utilize the Static Meter so that you can maximize static field reduction and minimize the effects of static re-generation by locating your equipment at the best possible points in the process.

Neal Raker, Application Engineer
nealraker@exair.com

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