Plumbing in air compressor lines... tips? tricks?

[Scot]

Here is my setup. The lines run on top of the purlin and each drop has a T with a trap below it.



The first revision used a 3x3x1. 5 T on both ends. The one on the compressor end cracked probably from being hard piped to the compressor. Or it might have been from the >100* heat... The 3x3x3 T looks to be stronger. Now I have a soft line going to the drier.

 

[Paychk]

Before you use PVC in a air line you may want to read this:



http://www.osha.gov/dts/hib/hib_data/hib19880520.html



If cost and availability are issues go with ABS, it splits instead of shattering on failure.

 

[Andy Perreault]

Thanks, Scot, that's what I had pictured in my head.

Andy

 

[merryman]

Does ABS come rated for pressures such as 125 PSI?

I would like to build one, but am a little nervous about the(remote I know, but with grandkids playing in my shop and sometimes banging things around,) possibility of PVC esploding and throwing shards about.



Vaughn

 

[Andy Perreault]

Originally posted by merryman

Does ABS come rated for pressures such as 125 PSI?

Vaughn

That osha.gov link that paychk posted mentions a certain type of ABS that is approved for compressed air.

Andy

 

[Paychk]

I'm not sure of the pressure rating for plain ABS, it should be printed somewhere on the pipe. There is compressed gas rated ABS pipe. Some of the info I found searching for the below sites state not to use common ABS for compressed air, it also states it must be labeled for compressed air use.



http://www.penaplas.com/capiping.htm



http://www.fabcoplastics.com/catalog/section1/1-25.pdf



http://www.ryanherco.com/auto/SECindex.cfm?FAM=175&SEC=160

 

[Scot]

Originally posted by Paychk

Before you use PVC in a air line you may want to read this:



http://www.osha.gov/dts/hib/hib_data/hib19880520.html



If cost and availability are issues go with ABS, it splits instead of shattering on failure.

Oh joy, looks like I have another project...

 

[illflem]

If you're worried about your pvc lines shattering just buy some black poly hose one size larger, slit it lengthwise and slip it over the pvc lines. Foam pipe insulation will also slow down potential flying debris.

 

[kaffine krazed]

If you use the right material you wont have to worry about the PVC shattering because there wont be any PVC. You should never use PVC for air lines.



If you insist on using plastic line go to a hose or industrial supply shop and get something that is rated for air systems. It will most likely be cheaper to use copper though the plastic line rated for air use is expensive.



I would recommend copper over black pipe because it is alot easier to work with.



I would have the main line sloped away from the compressor ending at a condensate drain. All the drops should come off the top then down using elbows. Tee off the drop at the level you want the quick connect fitting then continue down a few inches and have another condensate drain or put a water seperator on the drop. I would use float style drains that drain when the water level gets high. The line from the compressor to the hard line should be flexable and cappable of high temps. Have shut off valves place above on all drops and one at the compressor before it goes to the flexline. Also inline oilers if you are not going to be using the air to paint or sandblasting.

 

[Andy Perreault]

I haven't finished my water separator project yet. I thought I'd build something like what Scot made, only out of copper instead of PVC. I browsed around Home Depot, and the largest diameter copper pipe I saw was 2. 5". The largest PVC I saw that had a pressure rating was 2". The larger PVC pipes had stamped on them "not for pressure use". I'm thinking it might be better to just buy a regular air-compressor water separator instead. However, all I see are ones that have 1/4" NPT fittings for the in and out air lines. I will be plumbing the shop with 3/4" copper, so I don't want to have that restriction. Anyone know of a commercial-grade water separator that has 3/4" fittings?

While doing a search on the internet, I came across this very interesting web page from a do-it-yourselfer who put an intercooler on his air compressor: Intercooled air compressor . He modified the plumbing on the compressor so that the air goes through the cooler and a water separator first before going into the tank. Makes sense to me, I think it's a good idea.

Andy

 

[illflem]

Over the short distance of a filter/water remover 1/4'' will flow all the air your compressor can put out and 3/4'' pipe can carry.



Advantage of a pee trap type water trap is that the air cools releasing it's moisture. Unless your water separator is a distance from the compressor the air will still be hot.



The transmission cooler idea is good but one warning, never weld on you compressor tank like the guy in the article did.

 

[Andy Perreault]

Originally posted by illflem

The transmission cooler idea is good but one warning, never weld on you compressor tank like the guy in the article did.

I saw that, too, and thought the same thing, Bill. I have two used coolers sitting in the shop. They're not the "single tube snaking back and forth" type like in the Intercooled air compressor , but they're the "header" kind with vertical tubes on each end. I wonder what kind of pressures those things are rated at?

Andy

 

[illflem]

Andy I've had tractors with the single tube snaking back and forth type hydraulic coolers that took the full pressure of the high side, around 2000 psi, but the manifold type coolers are always on the return line.



I'd think that 50 psi is about the max for the type similar to a radiator and the AT and A/C coolers on our trucks.



I've used the type like below, which are what I call a manifold type, they're rated at 300 psi.



#ad