Highly Effective Air Dryer using Calcium Chloride as Desiccant

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Article: Highly Effective Air Dryer using Calcium Chloride as Desiccant

  1. Highly Effective Air Dryer using Calcium Chloride as Desiccant

    2 Comments by jimhopf Published on 02-21-2014 03:51 PM
    Early on, I learned the hard and expensive way that the air must be as dry as possible for use with a plasma cutter, or you'll just burn up the consumables very quickly. I went through a lot of consumables first starting out, because I didn't know just how important dry air is. I quickly noticed that I needed a new set of consumables after cutting out just a few things. In the summertime in Oregon, my air compressor seemed to be spitting out watery air.

    Below, I'll show how I made an air dryer using calcium chloride as the desiccant.

    First I bought a 1 micron water separator filter, and that helped, but not enough.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-air-filter-jpg

    It did increase consumable life. It was catching water droplets in the line, but not all the moisture. Consumable life seemed to about double, but this just confirmed that the air must be really, really dry. More research.

    The second thing I did was to make a Franzinator. The one I made was based on a design I found on other forums, just google it, it's just a pipe within a pipe where the air expands, cools and water condenses out of it. The Franzinated air was significantly dryer, and water droplets never showed up in the 1 micron water separator filter unit any more. Consumable life made a huge jump forward. Later, I put the bottom of the Franzinator in a 5 gallon bucket of water to help cool it, and it became even more effective. I'd drain the water out of the bottom of the Franzinator every few days, and it was definitely working well. I estimate that consumable life was about 10 times better.

    I don't know dry my air is dry enough, and I needed a way to test it. It passed the air blower on a paper bag test perfectly, but I noticed that when I stopped the flow of air, I saw a tiny bit of vapor for a brief second. hmmmm how to test....

    I still didn't seem to get the prolonged useful life out of the consumables. I think the air could be made even more dry. From further research, it looked like the only way to dry the air further was with a refrigerated air dryer, but I get a lot of crazy OTB ideas, and decided to continue to try to engineer my way out of this instead of fork over around $600-$1,200 for a good refrigerated air dryer.

    The test:
    I purchased a small inline desiccant air dryer. The silica desiccant turns pink to purple as it absorbs moisture. It was a little one, but it was enough to capture that small vapor trail from the air blower. Consumable life increased again! but still...... The silica gel began to turn pink, then blue quicker than I expected. I know calcium chloride is an awesome desiccant....

    Now the setup and chain of events are:
    1. Compressor to Plasma cutter - total consumable fail
    2. Compresor to 1 micron water separator/filter to Plasma cutter - helped, but still fail - but now at least the air is clean.
    3. Compressor head to Franzinator to 1 micron water separator/filter to Plasma cutter - general success
    4. Compressor head to water cooled Franzinator to 1 micron water separator/filter, to Plasma cutter. - incremental increase in general success.
    5. Compressor head to water cooled Franzinator to inline silica desiccant air dryer to 1 micron water separator/filter, to Plasma cutter - another incremental increase in success - good results.



    I planed to replace the silica desiccant air dryer with a calcium chloride desiccant air dryer.

    Calcium Chloride
    I scoured the internet for calcium chloride use as a desiccant for CNC, but could only find it used in large expensive industrial air dryers. I haven't found anybody posting a DIY to make a highly effective calcium chloride air dryer for plasma cutting machines. I also noticed that these industrial air driers have impressive moisture removal capabilities. Hmmmm, that gives me idea's.....

    I know that they sell calcium chloride in that highly over priced product called Dry-Z-Air for use in RV storage. Calcium chloride is also sold as ice melter for walkways, it's used in tractor tires to make them heavier without freezing in the winter, and I've used calcium chloride in concrete to make it fast setting concrete. I've noticed that in summertime, If I pour some calcium chloride on a dry spot of concrete, it will soon suck the moisture out of the air, dissolve and make a wet spot, which will stay there until it rains or washed away. You can buy prilled calcium chloride as an ice melter in most stores, or you can buy it from a mason supply by the 25/50 lb sack (keep it sealed!). Calcium chloride is very inexpensive, readily available, and highly effective.

    I know for fact, that calcium chloride can suck the moisture out of the air until it's perfectly dry - or close to perfectly dry, I don't have a way to test the increased dryness of air filtered through calcium chloride. Since the air is under pressure which is why water is squeezed out of the air in the first place, then compressed air passing through calcium chloride should be even more effective than just in ambient pressure, and it is!

    I suppose you could simply buy a silica desiccant air dryer, modify it, and fill it with calcium chloride, that's what I would do if I had one, but I don't. Also, considering that calcium chloride liquefies as it absorbs water and silica desiccant doesn't, so you need to be able to view it as it's used over time. A calcium chloride air dryer must be designed to prevent any liquids (water super saturated with calcium chloride) from passing through the air dryer unit. Also, a 1 micron filter should the last thing inline before the final dry air enters the plasma cutter to clean any type of dirt/oil particles, but especially any calcium chloride dust.

    Instructions:

    I had some requirements for a calcium chloride desiccant air dryer.
    1. I want the air to be forced to pass through as much of a bed of calcium chloride as possible to increase it's effectiveness.
    2. I want to see the entire bowl of calcium chloride to know to change it before it liquefies. I don't want super saturated calcium chloride water to pass into the 1 micron dryer/filter.
    3. It must be easy to maintain
    4. It must be inexpensive
    5. it must be safe


    Disclaimer: Try this at your own risk. The water filter is rated at 100 PSI cold water, while my air pressure is 150 PSI. Since I'm running a compressible gas instead of water through it, I'm sure this is perfectly safe because air doesn't create the water hammer effect, which the water filter is designed to handle, plus working load in PSI is 1/4 of bursting pressure (I hope).

    Purchase:
    1. GE Whole House Water Filter (clear bowl), comes with a filter. I used Model #GXWH20S
    2. Aluminum Duct tape, Gray tape may work, but the aluminum tape punctures nicely at the top and bottom of the filter without issue.
    3. Air fittings



    This is the working finished product.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_204032-jpg

    Cover the entire filter including both ends with Aluminum Duct tape, leaving 1/4 to 1/3 of the bottom untaped/open. Seal it well.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_201937-jpg

    Showing both ends were sealed, don't puncture the top or bottom, the filter will do that for you.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_202001-jpg
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_201949-jpg

    Showing how the filter will be installed. Open end of the filter goes on the bottom.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_202109-jpg

    The filter before pressing it into the bottom of the bowl which will center and puncture the aluminum duct tape.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_202658-jpg

    After the filter is pressed in, check for a good seal
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_202747-jpg

    Make sure it's centered, if it's off center (like in this photo), it wont move as you begin to fill it. You have to hold it until it's partially filled. Keep the filter press down as you fill it. Don't let any calcium chloride get under the filter!
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203131-jpg

    Hold it centered while pushing down on the filter, then fill.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203125-jpg

    Start filling it with calcium chloride
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203456-jpg

    Check for center, and bottom seal is still clean
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203345-jpg

    Fill it nearly to the top. Air will be forced down from the top through the bed of calcium chloride, and into the lower open part of the filter.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203627-jpg

    Screw the bow into the filter head, the top of the air filter will be punctured on center.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_202816-jpg

    Make sure the filter is on bypass.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203756-jpg

    Plumb and mount, install 1 micron water/air filter on the output
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_203852-jpg

    SLOWLY turn off the bypass to fill it with air, check for leaks
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_204107-jpg

    Test the airflow with air blower. The calcium chloride should not move or fly around
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_204154-jpg

    This is the calcium chloride i'm using, it's all the same stuff. You could use the Dry-Z-Air stuff too, its all the same.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_204230-jpg

    If using Ice Melter, make sure it says it contains calcium chloride- NOT SALT!!
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_204322-jpg

    Finished!
    You should not have any vapor trails with the air blower! Nothing but super dry clean air for about $60 bucks


    Air path: Compressor -> Franzinator -> calcium chloride air dryer -> 1 micron filter -> plasma cutter.
    I'm now getting the longest life I've ever had from the plasma machine's consumables. Consumables are lasting on par with what I've read.

    My setup?
    • Torchmate 2x4 (which I've outgrown after the first month...)
    • Cutmaster 80 Plasma Cutter
    • custom made water table



    Note:
    In a previous setup, I use an air tube to make the air filter up through the calcium chloride (don't do this, there are problems with this method), but anyway, where the end of the air tube met the calcium chloride, the calcium chloride had started to cake up! Suces!! and no vapor trails with the air blower! Now you'll have super dry air too without a refrigerated air dryer.
    Highly Effective Air Dryer using Calcium Chloride as Desiccant-20140214_205343-jpg

    One more thing, if you put some calcium chloride in a cup, it will liquify as it absorbs moisture from the air. But if let it sit there, it will continue to pull moisture from the air, and the liquid level will actually increase.

    I hope this helps

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  3. #2
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    Make sure you have a particulate filter after the dryer.....a by product of this type of dryer is often very small particles of dessicant (or calcium chloride) that will build up in the small passages of a plasma cutter gas control system as well as the torch head itself. Also, with any air system that uses filters/dryers upstream of the plasma cutter....there should be a pressure gauge upstream of the filter/dryer, and another one right at the inlet to the plasma. Compaing the pressures of these two gauges while air is flowing at the plasma torch is an invaluable tool to 1. ensure adequate input pressure is at the plasma, 2. to determine when the filter/dryer is saturated, clogged.

    The upstream gauge (under flowing conditions) will always show a higher pressure than the one at the plasma inlet. When the pressure at the inlet gets too low...cut quality and consumable life are affected.The vastmajority of tech service calls regarding cut quality, consumable life and the arc randomly extinguishing are related to air starvation, caused by restrictions in the air system.

    One concern, calcium chloride is corrosive with some materials, I'm not sure what affect it will have over time in the air system of different brands of plasma cutters.


    Jim Colt Hypertherm



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    Quote Originally Posted by jimcolt View Post
    Make sure you have a particulate filter after the dryer.....a by product of this type of dryer is often very small particles of dessicant (or calcium chloride) that will build up in the small passages of a plasma cutter gas control system as well as the torch head itself. Also, with any air system that uses filters/dryers upstream of the plasma cutter....there should be a pressure gauge upstream of the filter/dryer, and another one right at the inlet to the plasma. Compaing the pressures of these two gauges while air is flowing at the plasma torch is an invaluable tool to 1. ensure adequate input pressure is at the plasma, 2. to determine when the filter/dryer is saturated, clogged.

    The upstream gauge (under flowing conditions) will always show a higher pressure than the one at the plasma inlet. When the pressure at the inlet gets too low...cut quality and consumable life are affected.The vastmajority of tech service calls regarding cut quality, consumable life and the arc randomly extinguishing are related to air starvation, caused by restrictions in the air system.
    One concern, calcium chloride is corrosive with some materials, I'm not sure what affect it will have over time in the air system of different brands of plasma cutters.
    Jim Colt Hypertherm
    Thanks for your comments,
    Yes calcium chloride is corrosive in contact with metals. This air dryer system has multiple filters after the air passes through the calcium chloride. It doesn't change the PH of the air. I've been using this system for months and consumable life is excellent. I've got plenty of air volume and pressure, I keep it at 75 PSI at the tip.

    As for filtering, air travels through the calcium chloride, then:
    Filter 1 is the water filter itself for catching sediment which in this case would be the calcium chloride dust.
    Filter 2 is the 1 micron water water/dust filter
    Filter 3, (not mentioned till now) is the filter inside my A80 plasma cutter, which the manual says is a 5 micron filter.

    Also, I mention to test the airflow with a blower. If there was any dust that got loose during assembly, just blow it out first.

    I'm confident nothing larger than 1 micron will ever pass into my plasma cutter, and the air is bone dry.
    Life is good



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Highly Effective Air Dryer using Calcium Chloride as Desiccant
Highly Effective Air Dryer using Calcium Chloride as Desiccant