Compressed air piping discussion.

[Griffin]

I have the spec sheet next to me. A F72C 3AD XXX has 3/8 inch ports.

I missed where you said second set of numbers. Sorry.

Norgren makes the best small FRLs (filter-regulator-lubricators) in the business, IMO.



Tomorrow I will explain how to make a 60 gallon take become, in effect, an 180 gallon tank so one can paint with a smaller compressor.

[Roger P.]

I do this for a living. I deal in compressed air systems that are measured with thousands of horsepower and tens of thousands of cfm. Here's a couple of my guys working on a 12,000 horsepower air compressor:

Looks like the Cooper/Cameron MSG9+ we have at work. It's only 8000hp, but it has two Atlas Copco 2500hp HM7's, a 10000hp IR Centac, a 5000hp Brown Boveri and a 2500hp BrownBoveri to back it up. It will pull almost 1000A at full load. Each conductor to the motor is about as big around as your calf muscle.

The easiest way to keep water out of your air at home is to take air out of the top of a tee installed along a pipe run with drain legs installed at regular intervals along the way, not from the bottom of the pipe, or a downward pointing elbow, or out the end. Back that up with a good coalescing filter (not installed directly at the tank) and you should do ok. I'd keep an eye open for a small refrigerant air dryer in the local classifieds. It shouldn't take much to get one running if it's broken. Mostly the fans croak and the unit shuts down because it can't shed the heat from the refrigerant. Unless the compressor is shot, there's not much in them that is expensive to fix.

Black iron isn't that bad to work with once you know the trick to measuring it. Copper soldered with 50/50 works well enough that the copper will rupture before the joints let go. A few years back a company I worked for was the being sued because the compressor they rebuilt was involved in an explosion. Turns out, the compressor was remotely installed from the tank, but someone installed an isolation valve between it and the tank. The controls were on the tank, so they were receiving no pressure signal. The compressor kept pumping until something gave. The copper piping nearly ripped a guys forearm off when it went.

The main problem with plain solder is that it is a fire hazard, in that it become a source of oxygen in a fire when the solder melts and the system ruptures and releases air to the flames.

As a side note, in the wind tunnel I worked at, we had an 11250hp GEC centrifugal that put 300psi air into 50000cu/ft of storage. The air had to be super dry to prevent dew formation in the test section (-70F). Nevertheless, if operated at it's max speed of Mach 4.5, the air itself would liquify due to the extreme pressure drop through the supersonic nozzle. You really wanted to avoid this....We could dump 50000 cu/ft in under 20 seconds, creating about 2700 lbs/sec of mass flow. Someone told me it was roughly equivalent to 20 million horsepower being unleashed, but I'm not sure how he calculated that. I do know that someone left a crescent wrench inside once and I left an imprint in a steel I-beam deep enough to read the wrench manufacturers name in the beam.

[rustybronco]

I missed where you said second set of numbers. Sorry.

Norgren makes the best small FRLs (filter-regulator-lubricators) in the business, IMO.

I realized that after I posted post #45.

Griffin, I really appreciate you insight on this. Everything you have said has been given the utmost consideration towards building a proper air 'conditioning' system for home usage.

I had a small Norgren pressure regulator attached to one of my paint guns for years. I never had the slightest issue with it. In my humble opinion Norgren makes excellent products as well. I did buy an Exair water coalescer and pressure regulator recently. On the surface the units I bought appear to be well made.

[SVSooke]

I used to sell Norgren products, it's good quality stuff. But.

The filter you linked to is an F72G. The G stands for general purpose, which means it has a 5 micron particulate element. The element is not rated for oil removal. It will remove some oil, but it is not a specifically designed coalescing filter. The F72C would be a specific coalescing filter. It also is a very fine particulate filter.

So you have a 5 micron filter, you're halfway there. What you need now is a fine particulate/coalescing filter. The coarse particulate is necessary to protect the fine filter, otherwise the coalescing filter element would clog up quickly with particulate. What you want to do now is get hold of a Norgren F72C-2AD-ALO filter, which will get your remaining contaminants down to 0.1 micron particulate and 0.01 ppm oil content.

From the Norgren filter manual:

"Install an F72G filter with a 5 μm filter element upstream of the F72C filter foroptimum coalescing element life."


Typical oil carryover from a reciprocating compressor is 15-20 ppm oil content. That's no good for painting.

Great something else to buy.My wife will love it
Edit :do I NEED a F72C or will another C do the job.I have F72G-2AN-QE3,exactly the one I linked to

[rustybronco]

Greg, PM coming your way.

[SVSooke]

OK i guess I din't ask the question right.While a F72C 2XX-XXX would be ideal would a F73C-2XX-XXX or F74C-2XX-XXX work just as well?Or any other Norgren oil coalescing filter?Just trying to expand my search parameters.I believe the XXX-2XX-XXX that the 2 indicates I have 1/4 inch in and out ports,can someone confirm?

[Griffin]

OK i guess I din't ask the question right.While a F72C 2XX-XXX would be ideal would a F73C-2XX-XXX or F74C-2XX-XXX work just as well?Or any other Norgren oil coalescing filter?Just trying to expand my search parameters.I believe the XXX-2XX-XXX that the 2 indicates I have 1/4 inch in and out ports,can someone confirm?

Yes you have 1/4" ports. Now then.

Stick with a 72 or 73 series filter or regulator. These products work best at the flows they were designed for, particularly the coalescing filters. If there isn't a high enough impact velocity between the oil droplets and the filter media, they can just ooze through the media and pass downstream. Ideally you want the 72 series filters for flows up to about 10 cfm. Use the 73 series for flows up to about 22 cfm, and the 74 series can handle around 34 cfm. The minimum flows they need to maintain rated oil removal performance is about 10-15% of those numbers for each filter. The little 39 series are good up to 6 cfm, and you see them quite often as point of use filters on equipment that requires very little air, but it must be of high quality.


That doesn't mean they won't work at higher flow rates. They will, but you will have a higher differential pressure across the filter (lower downstream pressure), and they won't be as efficient at removing fine oil mist.

[SVSooke]

Thanks Griffin that was the info I needed,my little CH is listed as 4.7@40 PSI or 3.7@ 90.Might the 72 be to much then?

[Griffin]

Thanks Griffin that was the info I needed,my little CH is listed as 4.7@40 PSI or 3.7@ 90.Might the 72 be to much then?

Depends upon what you're doing. If you are using a tool that requires more than 5 cfm, you can still run it with your compressor, but you'll be running the pressure down in the tank while doing so. For example, if your compressor puts out 4 cfm, and you have 1 cubic foot of storage in your tank before you hit the minimum pressure for your tool, you can run your tool for 1 minute even though you're using more air than your compressor is putting out.