Compressed air piping discussion.

[850 Combat]

My dad used PVC in the early 80s for compressed air distribution in the garage of the house I now rent to my nephew. it hasn't developed leaks in the joints in a 'few years" I have put a coupling in it where there was damage from an impact.Fortunately, the impact was when there wasn't any pressure on the system, or there would have been more than likely a very dangerous explosion where sharp pieces of shattered PVC would have been flying through the air. I'm wondering if PEX would be suitable as a replacement. This compressor is an industrial unit sourced from a multi bay auto repair shop. It is equipped with a large condenser with a cooling fan on it. My dad painted numerous cars and motorcycles with it over the years, including one of my Nortons.

Any thoughts about PEX?

[Griffin]

PEX is a polyethylene compound, so is probably fine for compressed air usage. Be sure to check the pressure and temperature ratings for the specific item you're considering though. It needs to be rated for at least 180 degrees F and 200 psig if you're using a two stage, 175 psig compressor.


Back in the early '90s, there was a company that went through the upper Midwest selling compressed-air specific PVC piping systems, with a "lifetime" warranty. It was a quarter the price of black iron, with about 1/10th the labor. Lots of smaller shops (less than 100 horsepower of compressors) and a few larger shops bought the stuff.

Within five years, that company was bankrupt and out of business from warranty claims, but the guys who had worked there personally made a ton of money, so they didn't really care. I replaced miles of that stuff in the late '90s/early '00s with rigid metal pipe of one type or another.

[SVSooke]

That desiccant filter looks like the ticket Dale.Might even be able to find a suitable pipe in the "boneyard" at workIf not it shouldn't be that much to buy.

[rustybronco]

One section of pipe with two end caps suitably drilled and tapped for the air line connections. A couple of 50 micron screens and a method to support them in the pipe. Desiccant ($16 a quart) and one removable plug in the side of the pipe to check for colour change.

[SVSooke]

I was thinking it would be WAY more complicated.

[Griffin]

One section of pipe with two end caps suitably drilled and tapped for the air line connections. A couple of 50 micron screens and a method to support them in the pipe. Desiccant ($16 a quart) and one removable plug in the side of the pipe to check for colour change.

I was thinking it would be WAY more complicated.

Bear in mind that you need a coalescing filter upstream of the desiccant to protect it from oil contamination. Desiccant removes water from the air by ADsorption, which means the water molecules adhere to the surface of the desiccant bead. Desiccant ABsorbs oil, and once a desiccant bead is saturated with oil, water will no longer adhere to the surface. Oil saturated desiccant cannot be regenerated by heating it and boiling off the contaminant, so once it's contaminated with oil, it needs to be replaced.

[rustybronco]

I knew that oil would contaminate the desiccant. For my intended purpose, limited painting, I had hoped an Exair 9001 filter and a replaceable motor guard inline filter used ahead of the desiccant would go a long way towards increasing it's life. At $16 a quart for the desiccant, it could easily be considered a consumable to be replaced on a semi frequent basis.

But decided it best to get the real thing instead.

Ports are not threaded but I can rectify that.

http://www.ebay.com/itm/Norgren-Oil-Removal-Coalescing-Filter-NOS-in-Box-F55-001-L0D0-/281423343077?pt=Pneumatic_Hydraulic_Valves_Parts&hash=item4186236de5

[SVSooke]

I have this unit already http://store.norgren.com/us/en/detai...-w_-metal-bowl ,I hope that it would be good enough to get most of the oil out.With my luck it won't.

[Griffin]

I have this unit already http://store.norgren.com/us/en/detai...-w_-metal-bowl ,I hope that it would be good enough to get most of the oil out.With my luck it won't.

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.

[rustybronco]

Greg, the 'G' designation at the end of the F72 designates general. If it had ended in a C that means coalescing. Nothing lost as you'll need to use it before the oil coalescing filter.

What do you think of that F72G you have?

[Griffin]

Greg, the 'G' designation at the end of the F72 designates general. If it had ended in a C that means coalescing. Nothing lost as you'll need to use it before the oil coalescing filter.

What do you think of that F72G you have?

I use an F73G and F73C on my setup. The Norgren Excelon series also has nifty clamps the fit between the two housings so you don't have to use a pipe nipple in between them.

[rustybronco]

The 2 in the second set of numbers indicates 1/4 inch ports. A 3 would designate 3/8 inch port size. You can also use a SDO which designates a zinc bowl with sight glass. (spent all day looking at this krap)

[Griffin]

The 2 in the second set of numbers indicates 1/4 inch ports. A 3 would designate 3/8 inch port size. You can also use a SDO which designates a zinc bowl with sight glass. (spent all day looking at this krap)

That isn't exactly correct. the 2 and the 3 do designate the series is either 1/4' or 3/3", but you and get a 72 series in 1/8" ports, and the 73 series in 1/4" or 1/2" ports.

[rustybronco]

I was doing some poking around this afternoon trying to decide which series (72-73-74) would be best for another members setup. IIRC the 73 series held 3.5 ounces as opposed to the 72's 1.9 Oz capacity.

[rustybronco]

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