Compressed air piping

2Loose

reliable source of info
Just read through Indycars 5 page thread that ran last year on compressor installation and piping, very interesting info and comments....

I have an older 220 v commercial air compressor, a V style two stage, that has given me superior performance, and keep intending to upgrade my distribution system. I have a 20 x 40 open shop, high pitched v open beam ceiling, and as 99% of my work is done near that compressor, I have always just used a hose directly off the tank. When I need dry air, I have a large container of silica gel pellets that does an excellent job of drying any moisture coming out of the tank. With extra bags of dry gel available, and with the ability to dry the gel overnite in the oven when it gets to the right point, it seems to fill the bill pretty well for what I am doing. For my air tools, I run air tool oil through them at the end of every day they get used, and I use them a lot. I really only need the gel with tig welding and painting, and I don't do that much painting.

I have a bunch of brass 3/4" pipe I salvaged on a teardown job a few years ago, and was thinking of just putting about 20 each 10' legs zig zagging across my ceiling, which has about a 45 deg pitch, with the air traveling cross ways from top to bottom, releasing moisture as it cooled, and with a air/water separator at the bottom. Then lay some more pipe with outlets at several key locations in the shop and outside.
After that I'd still use the gel when tig welding and painting, but I suspect that by that time the moisture would be pretty much gone, lightening up the load on the gel container.
Any comments on how well this might work?

One other thing, several of my friends have used pvc for their air distribution systems, and I know this is considered a "no-no", due to the explosive nature of plastic pipe and compressed air in a pipe rupture situation, and also the vulnerability of plastic pipe to fire. My buddies point to the pressure rating of schedule 80 1/2" pipe at 850 psi, with an ID of 0.526", and say that by keeping the tank outlet valve shut off at all times when not using, the fire problem is negligible to nothing. And none of them have ever ruptured or caused a problem in any way, so my arguments to them have fallen on deaf ears. When I managed a large shop in the mid 80's, we only used black iron for our air systems, and had to have OSHA approval ( or the Hawaii equivalent called HIOSH) when installing or modifying.

Any other points I can make as to why they should not use pvc for compressed air systems?
Aloha,
Willy
 
P1000311.JPG


yes I know 3/4" sweated copper pipe is ideal, for air distribution piping, if its correctly laid out with drain points

and 3/4" black iron pipe is a good substitute,
but 3/4" schedule 80 or better yet 1/2" schedule 80 PVC IS easier to work with and a whole lot cheaper and lighter weight,
https://www.lowes.com/pd/Charlotte-Pipe-3-4-in-x-10-ft-690-Schedule-80-PVC-Pipe/3134567?cm_mmc=aff-_-c-_-prd-_-mdv-_-gdy-_-all-_-6154667-_-2470763-_-10935405&AID=10935405&PID=6154667&SID=453604488446008579:yiBSoSFHHxTH&cjevent=1584a7152f9411e9836801bb0a24060f
and I know plenty of guys who have had it in use for over 10 years in their shops with out problems, I think the main concern is to keep it out of direct sun-light, away from any heat sources like lights or electrical, and to use SCHEDULE 80 no larger than 3/4", RATED AT 690 PSI
and use 1/2" schedule 80 PVC preferred as its rated at 850 PSI,
not schedule 40 which is more common and much weaker.
if you look at this OLD PICTURE,taken before I installed the small air conditioner condenser radiators,and franzinator condenser moisture collector pipe,that I later installed above the compressors you'll see I ran a 3/4" schedule 80 PVC up into the rafters (white vertical pipe)and over to several places where I have quick connect points for air hose connections
and yes the dual compressors put out a max of about 140psi and as its rated at easily 4.9 times that, at 690 psi and its only under pressure when in use, I can,t see it as being an issue.
I also built a heat exchanger with an aux fan that works to dissipate compressor heat and condense moisture before it gets to the holding tanks or enters the distribution piping.
understand 3/4" COPPER PIPE is the IDEAL PIPE, 3/4" black iron is great, and I don,t advise anyone use PVC , if they don,t feel comfortable using it, .but yeah Ive been using it for about 21 years without any issues,
and yeah if I had access to 150-200 ft of 3/4" copper pipe, to re-due my shop, Id swap it out but I have yet to find any in a salvage yard at a decent price for obvious reasons
adding a oil cooler type radiator , or even several to the hot air lines leaving the compressor output , will allow you to cool and separate a great deal of the moisture from the compressed air
remotecolleryu.jpg



removing moisture from compressor high pressure air requires TIME , for the moisture in that air to condense,
DISTANCE, a long cool surface , like dozens if not hundreds of feet of metal pipe,will improve the odds of moisture collecting ,condensing and draining as the air cools, for the moisture to form on and drain, into, AND a pronounce reduction in air temperature or COOLING,obviously a condenser or radiator with its increased effective surface area and a fan to allow fast heat absorption will have benefits, keep in mind water or condensed moisture tends to run down hill , so giving it several places to collect that you can easily drain and pulling air you want to remove the moisture from, only from higher points placed after the air flow has had a chance to cool and condense is far smarter, design features, in planing your shop.
draw01.jpg

viewtopic.php?f=27&t=24

http://garage.grumpysperformance.com/index.php?threads/franzinator-air-dryer.6246/

viewtopic.php?f=59&t=6246&hilit=franzinator

http://flexpvc.com/PVCPipeSize.shtml?gc ... MgodRzUAog
scd80.png


coppercoollines.jpg

heres a picture of a guys shop where he obviously went to a good deal of work and expense to get the compressor to supply dry air.
understand the concepts well as the heat radiating copper pipe must be used to condense the moisture in the hot compressed air,
the pipe must be connected to the compressor output,
before it enters the holding tank NOT after the holding tank, to work correctly
 
Last edited by a moderator:
2Loose said:
I have a bunch of brass 3/4" pipe I salvaged on a teardown job a few years ago, and was thinking of just putting about 20 each 10' legs zig zagging across my ceiling, which has about a 45 deg pitch, with the air traveling cross ways from top to bottom, releasing moisture as it cooled, and with a air/water separator at the bottom. Then lay some more pipe with outlets at several key locations in the shop and outside.
After that I'd still use the gel when tig welding and painting, but I suspect that by that time the moisture would be pretty much gone, lightening up the load on the gel container.
Any comments on how well this might work?

Aloha,
Willy

Do they really make Brass pipe or did you mean copper? I used copper for the
very reason that you stated above about condensing the water out of the air
by cooling.

Before I would run PVC, I would purchase a kit made for compressed air and
made of high-density polyethylene (HDPE) tubing with aluminum core stays
flexible and will not become brittle or lose strength over time. MaxLine meets
OSHA requirements.

With o-ring connections and you can bend it my hand, it just doesn't get much
easier to install than that.

If I was to do it again, I would seriously consider this product or something
similar. I very rarely get any water out of the receiver tank. I think it's because
of the inter-cooler and Franzinator. 98% of all the water is drained from the
Franzinator. Not even once have I gotten any water out of the first drop that
I installed between the bench and heater.

For $199.99, it's alot cheaper than copper.

http://www.northerntool.com/shop/tools/ ... _200484023



When you use desiccant, does that produce any dust in the system? Do you
need a particulate filter if using desiccant?

 

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One day I should take some pictures and do a writeup on my air system.
However this setup posted above is VERY good.

upload_2020-3-22_18-5-8.png

My setup is very close to it, the only difference is I have about 50ft or more of copper pipe before the manifold setup.
The idea being that you cool down the air, and the do the up and down with a drain in order to separate moisture.
I get pretty much zero moisture in my filter or out of the line with this setup.
To get any sign of it, I would need to run my compressor VERY hard in order to start filling up the drains.

Also having an Auto tank vent helps a great deal.
https://www.grainger.com/category/p...m-components/timed-electric-auto-drain-valves
 
There are a lot of options for the cycle time and purge time, which drain are you using ?
 
Nice little unit, has a button at the top for a manual purge.
But the fuse box method is by far my favorite.
Especially with the compressor outside of the garage, locked in a shed.
 
My compressor is the Quincy QT54
I have been very happy with it so far.

After i burned up two smaller compressors, i decided i would be better off in the long run.
 
Speedair 1/4in fittings.
I was really interested in the timing numbers that you are using?

I have also have a Quincy 60 gal, but it's only a single stage. I don't have alot of air tools, so it
fits my need pretty well.
 
For daily use i keep it at its max timing, i would need to go outside and look.
Quite honestly i wish it had a 24hr setting.
Vents way to often.

Fastest setting, is a little too fast.
Maybe if i was painting i might use it to keep all water out.

Then there is the duration timing.

I use that along with the factory drain valve to control how loud the venting is.
Then turn up the duration to ensure it actually drains all of the water out.

It's all trial and error.
 
Also, i got the auto drain in the first place as the compressor sits out side, and it gets very cold here during the winter.

I wanted to reduce any freezing at the bottom of the tank.
 
Nice fresh spring morning, a mix of snow and rain... :rolleyes:

As I look at these nice pretty copper pipes, and marvel how well the guy did on it (fantastic work).
upload_2020-3-28_11-57-18.png

Something I remembered.

When I did my air system, I had my neighbor help me.
He does HVAC for a living, mostly new construction.

He taught me how to solder pipe, and would critique my joints.

Doing lots of joints?
You need this: https://www.homedepot.com/p/Bernzomatic-TS4000KC-Trigger-Start-Torch-Kit-TS4000KC/203368730
upload_2020-3-28_12-4-8.png
An absolute time saver, I used my neighbors torch for a bit and decided I wanted the same one.
I found many other uses for it, heating rusty bolts, to heating parts before pressing a part into them.

My first run was with my neighbors solder, later I moved onto this stuff
Harris Solder Kit SB861 & SCPF4 - Stay-Brite #8 Silver Bearing Solder with Flux
upload_2020-3-28_12-9-34.png

The "stay-clean" flux alone is much easier to control, less mess.

Another thing I learned from my neighbor is to bleed off some of the flux around the joint when done, this cleans the pipe to a like new appearance.
Cool/wipe off with a damp paper towel, also serves to steam clean.

Next thing I learned, valve grinding compound can do a great job of both cleaning up copper pipe to look new again after a sloppy solder is filed, and sanded down.
Complete with a buffing wheel and polishing compound for a real smooth shine!
https://www.harborfreight.com/1-1-2-half-inch-x-2-inch-cylinder-buff-65000.html
https://www.harborfreight.com/power...arter-lb-dark-grey-polish-compound-96769.html

Bad part, the copper still dulls over time.
I thought about some clear coat, but I already spent way too long with my first manifold. :D

When buying pipe, there are two different grades at the local stores.

Water pipe is cheaper, and has the thinnest wall "Type M"
HVAC pressurized rated (thicker) pipe = "Type L"
Most of my system is "Type K", industrial (Thickest) grade thanks to my neighbor, and is total overkill.
The rest of my system is "Type L"
 
I fully agree on the MAP gas and external torch handle, it makes life so much easier! Mine is done
in copper also and on a couple of joints I had to use two torches at the same time.

Also what they call 1/2" in HVAC might be 3/8" in plumbing, that was so frustrating trying to get
the right size and not knowing what's going on.

To remove moisture I use a Franzinator. My first drop is about 25 feet after the tank and I've never even
gotten a mist to come out when I opened the valve. For painting I have a CamAir CD3 filter dryer.

http://garage.grumpysperformance.com/index.php?threads/franzinator-air-dryer.6246/
 
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