air dryer for compressed air system

jimg · Feb 20, 2009

While not exactly what I was looking for something like this would work too...
Electric purge valve

Scooby074 · Feb 20, 2009

Ive seen on the net where people have made coolers out of the core from old house radiators. I think they are the "slant fin" type. Basically they're just soldered into a copper manifold on both sides. To increase the cooling, a exhaust fan is mounted in a shroud. The end result is similar to a industrial hydraulic heat exchanger. This might be easier than getting involved with a refrigerated system. The copper cooling lines can be picked up as scrap from remodels. This is probably the cheapest way to get forced cooling for a air system.

Ken_CT · Feb 20, 2009

You might be interested in making a deliquescent type dryer. They are different from a desiccant dryer as the deliquescent uses a salt tablet that absorbs moisture as it dissolves the tablets. The water is then drained from the bottom, and the tablets are simply replaced. These dryers reduce the pressure dewpoint by approximately 20 deg. F., which would be good for your purpose. The dryer is simple to make, but you are fabricating a pressure vessel, and that is another topic entirely. No filter, coalescing or other can remove humidity, only water vapor. The type of setup Scooby074 was talking about will work, but will only bring the pressure dewpoint to ambient temperature. I've seen where a water mist is sprayed on the fin tube before the fan to make a "swamp cooler", but that just complicates things more. A refrigerated dryer will give a pressure dewpoint of approxamatly 38 deg F, and a regenerative twin tower will go about -40F while molecular sieve type are about - 100F, but I don't think you're looking to spend thousands of dollars

. Keep in mind the pressure drop from anything you put in the line. Whichever type you use, whether refrigerated, dessicant, or deliquescent, don't forget the filters, as the cleanliness is as important if not more so, than the dryness of the air. I read earlier that "this isn't rocket science". It actually is. There is a lot of engineering that goes into, or should go into an air system. Here is a link to Van-Air, a maker of deliquescent, dryers. They make a fine product. Also look into Wilkerson and Norgren for more info on drying air.
Deliquescent Dryers

Scooby074 · Feb 20, 2009

Personally i prefer the desiccant and coalescing system. My air is very dry as it is now, but i have been considering adding a fan assisted cooler if i can find the parts cheap. It will improve my efficiency ,reduce the air temp and reduce the load on my desiccant beads.

THe deliquescent system sounds interesting, but the salt used in it appears to be a consumable. The advantage of a (silica) dessicant is its reusable.

DieselPower · Feb 21, 2009

jimg said:
While not exactly what I was looking for something like this would work too...
Electric purge valve

No need to get fancy like that. I think you said you just wanted one that would be activated by a raise in the water level. You could easily build one yourself using a simple pneumatic electric solenoid valve that is actuated by a water sensor.

SpringHollow · Feb 21, 2009

Hard to build one that justifies the effort versus buying the timer type.

I also got some of the valves they use on trucks with the pull cable to drain the tanks.

Ken

jimg · Feb 23, 2009

Thanx VERY much for the help!!!

Ive seen the variety where a radiator of some sort is air blown over it w/ a small fan. Just want sure how well it would work. Does it really cool the air enough to drop a significant portion of the moisture. Thats the reason I was thinking along the lines of cooling the air around the coil/radiator.

Never heard of a deliquescent type. Thanx for mentioning it w/ the link. Any idea how much the salt tabs cost?

"No need to get fancy like that. I think you said you just wanted one that would be activated by a raise in the water level. You could easily build one yourself using a simple pneumatic electric solenoid valve that is actuated by a water sensor."

LOL, the only reason I mentioned that particular switch was b/c I could figure out how to build the other.

I figured the timer type would work OK and perhaps come out a bit cheaper. If you could be more explicit that would help a lot.

tglass · Feb 23, 2009

jimg, I've priced one with a water sensor and it was pretty high priced. Think I could build one alot cheaper, but the problem is finding the water sensor at a cheap price. Any ideas on that?

Redneck in training · Feb 23, 2009

Search google for vortex coolers. You might be able to make one and use it as second stage cooling to drop temperature bellow ambient. We use them to cool cabinets with control systems in hot environment.

Scooby074 · Feb 23, 2009

jimg said:
Thanx VERY much for the help!!!

Ive seen the variety where a radiator of some sort is air blown over it w/ a small fan. Just want sure how well it would work. Does it really cool the air enough to drop a significant portion of the moisture. Thats the reason I was thinking along the lines of cooling the air around the coil/radiator.

Never heard of a deliquescent type. Thanx for mentioning it w/ the link. Any idea how much the salt tabs cost?

"

From the Kaeser air compressor site :"Highly efficient air-cooled aftercoolers from Kaeser are an economical way to remove water vapor and cool compressed air to safe, usable levels for many applications. They also prepare the air for further filtration and drying.

Compressed air is cooled to within 5ｰF to 20ｰF of the ambient temperature, and as the air cools, up to 80% of the water vapor condenses to a liquid."

KAESER USA ? Air-cooled Aftercoolers

They're also available watercooled for better performance.

From the Deliquescent site, the salt tabs were around $50-60 for 50 lbs. I dont know how long they'd last. The Silica desiccant I use is around $80 for 1Gal, but its reuseable.