Supply Side Review: Deliquescent Type Dryers

As mentioned in my post last week.  The supply side of compressed air systems within a facility is critical to production.  The quality of air produced by your compressor and sent to the demand side of the system needs to be filtered for both moisture and particulate.  One method to dry the air, that is the topic for this blog, is deliquescent type dryers.

These dryers operate like an adsorbent dryer such as a desiccant medium dryer.  The main variance is that the drying medium (desiccant) actually undergoes a phase change from solids to liquids.  Because of this the material is used up and cannot be returned to its original state for reuse.   The liquids formed by the desiccant dissolving in the removed water vapor are then filtered out of the air stream before it is passed on to the demand side of the air system.

There are many compounds that are used to absorb the moisture in the wet compressed air.  A few options are potassium, calcium, or sodium salts and many that contain a urea base.  The desiccant compound must be maintained at a minimum level for the dryer to contain enough media to successfully dry the air.

These dryers are generally a single tank system that is fed with compressed air from a side port near the bottom of the tank.  The air then travels up past drip trays where the desiccant and water mixture fall and ultimately ends up in the bottom of the tank.  The air then goes through a material bed that must be kept at a given level in order to correctly absorb the moisture in the air.  The dry air is then pushed out the top of the tank.

As the desiccant material absorbs the liquid from the compressed air flowing through the tank it falls onto the drip trays and then into the bottom of the tank where it is drained out of the system.  This process can be seen in the image below.

 

Deliquescent type compressed air drying system
How a deliquescent air dryer works – 1(VMAC Air Innovated, 2017)

 

The dew point that this style dryer is able to achieve is dependent on several variables:

  • Compressed air temperature
  • Compressed air pressure / velocity
  • Size and configuration of the tank
  • Compression of the absorption media
  • Type of absorption media and age of media

These dryers are simplistic in their design because there are no moving parts as well as easy to install and carry a low startup cost.

Some disadvantages include:

  • Dewpoint range 20°F – 30°F (Again this is according to the media used.)
  • Dissolved absorption material can pose a disposal issue as it may not be able to be simply put down a drain
  • Replacement of the absorption material

Even with disadvantages the ability to supply the demand side of a compressed air system for a production facility is key to maintaining successful operations.  If you would like to discuss any type of compressed air dryer, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

1 – Deliquescent Dryer Image: VMAC Air Innovated: The Deliquescent Dryer – https://www.vmacair.com/blog/the-deliquescent-dryer/

 

Is PVC Pipe Alright to Use with Compressed Air?

A question arises every now and then on whether or not PVC pipe, yes the stuff from your local hardware store that says it is rated for 200 psi, is safe to use as compressed air supply line.   The answer is always the same,  NO! OSHA agrees – see their statement here.

Schedule 40 PVC pipe is not designed nor rated for use with compressed air or other gases.  PVC pipe will explode under pressure, it is impacted significantly by temperature and can be difficult to get airtight.

PVC pipe was originally designed and tested for conveyance of liquids or products that cannot be compressed, rather they can be pressurized.   The largest concern is the failure method of the piping itself.   When being used with a liquid that cannot be compressed, if there is a failure (crack or hole) then the piping will spring a leak and not shatter.   When introducing a compressed gas, such as compressed air, if there is a failure the method ends up being shrapnel.  This YouTube video does a good job of illustrating how the pipe shatters.

While it may seem that it takes a good amount of pressure to cause a failure in the pipe, that is often not the case.  I have chatted with some local shop owners who decided to run PVC as a quick and cheap alternative to get their machines up and running.

They each experienced the same failures at different points in time as well.  The worst one was a section of PVC pipe installed over a workbench failed where an operator would normally be standing. Luckily the failure happened at night when no one was there.  Even though no one got injured this still caused a considerable expense to the company because the compressor ran overnight trying to pressurize a ruptured line.

Temperature will impact the PVC as well. Schedule 40 PVC is generally rated for use between 70°F and 140°F (21°-60°C). Pipes that are installed outside or in non temperature controlled buildings can freeze the pipes and make them brittle.

If you haven’t worked with PVC before or do not let the sealant set, it can be hard to get a good seal, leading to leaks and a weak spot in the system.

The point of this is the cheapest, quick, and easy solutions are more often , the ones that will cost the most in the long run.

If you would like to discuss proper compressed air piping and how to save compressed air on your systems, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Image courtesy of: Dennis Hill, Creative Commons License

Video Blog: EXAIR’s Soft Grip Super Air Scraper

The video below showcases a new EXAIR product, the Soft Grip Super Air Scraper. This combines the comfort of a Soft Grip Safety Air Gun with the powerful air stream of the 2″ Flat Super Air Nozzle and adds the scraping ability of a handheld scraper all in one convenient package.

If you would like to discuss your application, please contact us.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

 

Helping Within Our Community

Throughout my tenure here at EXAIR I have seen the company give to many different organizations and to the team members here.   Recently we implemented a program where employees are allowed to choose a charity of their choice to go and volunteer for a day each year.  This year for my volunteer day a group of seven members from EXAIR went to help a non-profit organization that focuses on helping students and teachers in 16 local counties.

The organization, Crayons to Computers is a free store for teachers in these counties that surround Cincinnati.  The store is stocked with donations from corporate and private entities and staffed by volunteers.  Their inventory can be anywhere from classroom supplies, books, decorations, technology equipment, even stocked book bags to give to students.  The store is the largest of its kind here in the United States and has been serving the Cincinnati area for 20 years. Their belief is that a teacher should not have to spend money out of their pocket to supply students in need with school supplies and to ensure that schools in need have access to supplies that aren’t always easily available.

They have a sales floor where the teachers shop and then a large warehouse where the donations are all sorted and stocked for easy pull to the sales floor when needed.  This is where our team spent the day.  We did jobs like sorting books by reading level, organizing / packaging chair mats, unloading trucks, and finally, consolidating over 30,000 boxes of 24 count crayons so that their valuable warehouse space was being used more efficiently.  These crayons were all donated by financial institutions here locally that had challenged each other to see who could donate more.  It still isn’t the amount of crayons that they will supply to teachers within this school year, but it helps tremendously.

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By volunteering our time we were also able to give 10 teachers who’s school would not normally qualify for shopping at Crayons To Computers the ability to go and shop for a day.  This was an added bonus that we were made aware of after the fact.  This is yet another way that Crayons to Computers gives to our community.

One of the best takeaways I have from this year is that I got to give back to an organization that my amazing wife would shop at when she was teaching students in need.  It was organized by someone here on our team that had no knowledge of my personal connection. We ended up getting more done than they had ever hoped to get out of 7 volunteers.  This was all made possible by a company that doesn’t just focus on making excellent products and providing top notch customer service.  EXAIR is also focusing on making sure our team members interests are embraced by letting them choose how to give their time and the companies time to a cause they believe will give back to our local community.

If you would like to inquire about donations or how you could help Crayons to Computers, please check out their site directly.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF
1-800-903-9247