Intercooled Air Compressor

[parkour]

Oh. $34/yr isn't much compared to other shop costs.

[yotarover]

i just went and picked up a couple dryers from hf got 1 before the hose,and one mid section of my 100' hose. then another at the end with a small extension to give some space between the tools. works like a charm now. my dart cut off tool barely spits out any thing now.

[Timberwolf]

sweet. But if they are the small inline dessicant ones they will be saturated in no time with that much water going through the lines

[jakeru]

I did some work at a shop today that had a twin-screw compressor with a built-in dryer. Wow, talk about a quiet compressor! You could hold a conversation standing right next to it. About the same noise level as a very loud refrigerator.

[yotarover]

wish there was some way to filter/dry it at the intake port. i just drained it out i bet i could have filled a milk jug half way or more

[parkour]

OK, head over to Wal-Mart and grab a $98-special window air conditioner. Remove the fan that blows over the evaporator, and build a duct so that air going into the compressor must to flow over the evaporator. Install an automobile air filter in there somewhere and there you go. The air will flow over the evaporator so slowly, since it is just the air compressor pulling the air through, that it should result in plenty possible time-in-contact with the coils to remove a high percentage of the moisture.

If you have the number of gallons of air you air tank will hold, the starting pressure, ending pressure, time to fill, and dimensions of the evaporator; it would be trivial to compute the speed of the air, and hence time to possibly be in contact with the evaporator.

Here is a nifty humidity/dew point/etc. calculator I found.
http://www.humidity-calculator.com/index.php

[Rivets]

Hi Parkour,

Have you actually tried this ?

Not sure it's that simple.

The air flow through the evaporator that is drawn by the compressor's intake would have to match that provided by the fan. Otherwise the AC's operating equilibrium would be upset and it would/should auto shut down.

Also, the AC would have to be ON only when the compressor is running.

rivets

[parkour]

No. I have not tried it. I think you might be right.

My thought was that the AC would need to be started a bit before the air compressor because the AC will not be able to chill immediately. I assumed that at most, the AC would freeze up the water on the evaporator, but I had not thought that it might freeze up the refrigerant as well. I dismissed any possible problems like that, assuming that the duty cycle would be so low that nothing too exciting would happen.

It is an interesting idea (to me at least), but probably one of those things that won't make it out of the "Hmm.. I wonder..." phase. Furthermore, it is no doubt much easier said that done... just like building a reasonably polished water cooler for a TIG torch; simple in concept, but quite a bit of work to pull it all together in a robust way.

[Timberwolf]

The easiest thing to do for a casual user would be submerge a cooler such as mine in a bucket of ice water. Extremely cheap and if you are just using it occasionally, who cares about having to add some ice when you plan on doing a days work. Just a thought but with just the fan on my 6 pass it's working great and I have no reason to change it for my use

[parkour]

huh, ice > a/c.
simple > complex.

Do you use an in-line dryer? If so, how long does it last now that you have the intercooler?

[Canada]

My need for dry air is for my cup gun and sand blasting cabinet. My concern with the chemical air dryers is with the excessive loss of CFM, unless u spend a lot of $$$ on a large volume commercial unit. Otherwise these units create a real bottle neck. I considered running copper through a bar fridge but air is a real poor conductor. I felt the air would move to rapidly through it before it chilled enough to remove enough moisture.

The solution I choose (see pictures) was to run the air through a "water tower" that would have enough thermal mass to stay efficient. There would be no loss of CFM and if I needed really dry air I fill it up with snow (winter) or ice (summer). I haven't tested the air but there is NO water in any of the traps beyond the water cooler. I used 3/4" copper all the way from the compressor, through the "water tower" with used 3/4" recycled slant-fin heat rad line inside the water tower in both directions to facilitate better efficiency, up to the filter and pressure regulator. At the bottom you can see the tap to drain the tower and the bleed off valve to remove accumulated moisture from the system.