Air Compressor Header Sizing

[mrtonegto]

I'm about to install air compressor lines in my shop and I've read a great many of the threads on the subject but one thing still eludes me. What affect does header pipe size have on the total footage of air piping?

Since I'll be doing considerable sand blasting I want the remove the great majority of water in the lines. The consensus seems to be that you have 50+ feet of line before the drop that feeds the sand blaster, etc. - in order for the air to have sufficient time to cool and drop the condensation.

But 50 of black pipe is a lot of threading; *******; unions, etc. and I'm dealing with some close quarters. What about if you used a 2" or 3" header right off of the flex line from the compressor? Let's say 15' of that large pipe. Could you then reduce the 50' requirement to 20 feet additional feet of 3/4", or whatever??

 

[volleyball]

It is the cooling and the more steel, less air will give you better cooling. You can get some 20' pipes to cut out a couple of fittings.
Adding heat sinks and maybe forced air will help. You could do a pipe in pipe thing and make a water cooler.

 

[mrtonegto]

Unfortunately 20' lengths won't work in the space I'm working with and that's why I'd like to see if a large diameter pipe would make a difference regarding total running footage.

 

[volleyball]

It would mean you would need to run more pipe. Copper transfers better than steel but you need a buffer to limit electrolysis.

 

[mrtonegto]

That seems contrary to other posts, like suggesting you use the largest line right off the compressor to increase efficiency.
Isn't there more surface area in a 2" pipe to help cool the incoming air?

 

[sberry]

Dumping it in to a big pipe couldn't hurt. That's part of the principle of the Franz ****. I use a similar setup, My comps dump in a common tank before plumbed to manifold. It helps.

 

[volleyball]

A large pipe will allow for more air flow and act as a sort of aux tank. That is not the issue the OP is wanting to address.

 

[sberry]

Its related to the issue, more steel, more area bigger heat sink and because it flows more less velocity.

 

[hickfied]

I beleive you want a large header pipe for the volume of air the blaster will require, which will theoretically not cool the air as much as a smaller inner diameter pipe.

The larger pipe will have more inner surface, but when comparing volume capacity vs inner surface area of two pipes, the smaller will have more surface to volume.

 

[sberry]

This depends on volume, these blasters are air hogs compared to the comps they are hooked to, a 1/2 pipe supplies most of the common ones just fine to 30 cfm or a bit more.
There is more concern over pipe size for "efficiency" than its worth and the object isn't to dump s much air as you can but to get the most from it.

 

[volleyball]

Since we don't know the details and only guess, I would think a chiller to cool the air and some copper, aluminum or AL PEX line to snake its way without fittings would work best to feed the blaster.

 

[sberry]

My ideal is a screwed 1/2 black iron pipe to valve, if to blaster 1/2 hose barb screwed to valve and machine. I don't have a cab but a pot so I do use heavy connectors and 25 ft 1/2 hose at about 30 cfm. Still run out of air way before hose size is any issue.

 

[mrtonegto]

Restating my question a differently: Can I run 1" diameter black pipe a lesser number of feet than 1/2" black pipe and get the same affect in removing condensation? Let's say I run 30' of 1" - would it equal 50' of 1/2??
To go from there............ would 20' of 2" accomplish the same??

 

[volleyball]

No, no and no.
The larger pipe has more steel but the inner air flows more and it is insulated, so less cooling.

 

[mrtonegto]

So "time in pipe" has a major affect on the cooling.

Kind of like "time in grade" has a major affect on military pay............