CU air lines for home shop - what diameter?

On Mon, 22 Dec 2003 21:29:28 GMT, Mark wrote something ......and in reply I say!:

When I used to hare about on a motor bike, I though I could feel the performance difference on a cold morning. I thought I was imagining things until I leraned the principles. So I don;t think I _was_ imagining it, or looking for it.

**************************************************** sorry remove ns from my header address to reply via email

I was frightened by the idea of a conspiracy that was causing it all. But then I was terrified that maybe there was no plan, really. Is this unpleasant mess all a mistake?

Another good site for layout and design of a air piping system is at TP tools

vfp

On 22 Dec 2003 20:18:40 -0800, snipped-for-privacy@hotmail.com (Eric D) wrote something ......and in reply I say!:

Does _anything_ eat black poly pipe? HDPE I think. Almost untouchable.

**************************************************** sorry remove ns from my header address to reply via email

I was frightened by the idea of a conspiracy that was causing it all. But then I was terrified that maybe there was no plan, really. Is this unpleasant mess all a mistake?

Ester based fluids eat damned near any polymer. I believe lubricants used in R134 systems are ester based.

The combination of Google and Usenet is a beautiful thing. At any one point you can find someone else tackling the same project as you, and learn along with them. It just so happens that I'm installing air distribution lines in my shop, and have been able to confirm in triplicate almost all of the safety and convenience dos and don'ts of the job before tackling it. I do have a couple questions that I haven't found answers to:

1. A lot of discussion has centered around the size of the pipe for distribution. Is this in reference to the main distribution lines, or the system as a whole? For instance, say I have an 80G 175PSI compressor that can deliver ~17 SCFM, and I want to run a closed loop distribution that has a perimeter of 80 ft. around my shop. Most recommendations I've seen for this configuration would recommend 3/4" pipe, because of the SCFM and the length of the run. My question is in regards to the drops for tools around the shop. If the main line is 3/4", should the drops all be 1/2"? Should the length of all the drops be included in the calculations for pressure drop in the system? Any recommendations?

1. My compressor has an air outlet that is less than 3/4". If I were to run 3/4" pipe through my shop, what should I do about this? Should I use a reducer at the connection, or should I install a new fitting on the compressor with a larger outlet?

Thanks in advance for your help.

3/4" mains, 1/2" drops would be fine. As for the outlet, just use the existing outlet, but increase the pipe size to 3/4" right away. Greg

A short (< 10') drop of 1/2" copper will flow 50 cfm at a negligible drop (<

1 psi) - your regulators (if they aren't premium high-flow), connectors (biggest factor), valves (if they aren't full port) and hoses will be the limiting factors long before the drop size comes into play.

Just increast it to 3/4" as close as practical. I use a 1/2" i.d. stainless braided water heater connector, that happens to have 3/4" pipe threads on the ends.

DWYL. On the one hand, it's a shorter section of 1/2". On the other hand

1/2" is not so very much cheaper than 3/4". For computing pressure drop, if it's a one user shop, you can compute for each drop as the feed from the compressor plus the drop. If 5 different air drops will be used at once, it's a different ballgame, and one I'll leave to others.

If you need to machine the compressor to put in a larger fitting, don't bother. If it's a matter of unscrewing a current small connection so you can screw in a larger one, do that. Again, limited length of the restriction (expanding to larger pipe sooner, rather than later) will help, all else being equal.

Actually, half inch line is large enough for the flow and distance. Since the individual drop lengths only impact their respective individual drops, including the length of *one* of them in the pressure loss calculation will be sufficient.

You want a piece of flex connecting between the tank and the distribution piping. This isolates vibration and prevents fatigue failure of the piping at the join. Since flex offers more resistance to flow than rigid pipe, you'll want to use 3/4 hose here. Adapt the flex down to the valve on the tank, which should be a half inch ball valve which screws directly into the tank outlet.

Gary

Gary Coffman wrote in news: snipped-for-privacy@4ax.com:

Here is another little trick you can do when plumbing this up to help reduce the water getting into your system. Out of the compressor, create a P trap with a 1" or larger diameter drip leg/container and a valve at the top and bottom. from the upsweep of the P trap, use 3/4" coil copper tubing and create a vertically rising coil with a minimum of 1" air space between coils. This will increase your total line run by several feet, but it acts as a cooling coil (air to air heat exchanger) for the air exiting the compressor. The water that condenses out will run back down the coil, into the P trap and into the drip leg/container. (Think Moonshine Still) The valve at the top of the container allows you to block off line pressure while you open the bottom valve to drain the water out.

We put a T in the middle of the P trap, then a ball valve then expanded up to a piece of 2" galvanized pipe 12" long then reduce back to a 3/4" ball valve at the bottom for drainage.

I highly recommend automatic timed drains. These will dump air on a preset timed bases for a few seconds. You don't have to worry about trying to remember to drain the resevior.

Check out this site

Although they don't recommend copper or pvc (me either on the pvc), I still found it informative.

Dave Young

On Sun, 18 Jan 2004 04:41:46 GMT, "Toolbert" brought forth from the murky depths:

With one user, 1/2" pipe all around would suffice. With 2 concurrent air users, 3/4" might prevent any bottlenecks if you use 90° elbows at all bends. Since most air tools use fittings with 1/4" pipe threads, the limiting factor is their smaller ID. All of the off-the-shelf quick-disconnect fittings I use have a 3/16" ID (~0.190").

100' of 3/8" ID air hose will flow 42cfm @ 90psi. 100' of 1/4" ID air hose will flow 16cfm @ 90psi. A 3/16" orifice will flow 53cfm @ 90psi. (The hose is much more of a limiter than the orifice.)

Recommended pipe size is 1/2" for 100' with a 15cfm throughput, about what your compressor puts out. (Handyman-In-Your-Pocket)

Don't forget the 7 P's: Proper Prior Planning Prevents Piss-Poor Performance ----------------------------------------------------

Website Application Programming

Do you have a refernce for the formulae for these? I wish to implement the calcs in APL and have not found formulae for them. Also, is your use of cfm refering to the volume at pressure or is it equivalent one-atmosphere volume.

I like it! Mind if I steal it?

Ted

On Sun, 18 Jan 2004 19:04:42 GMT, Ted Edwards brought forth from the murky depths:

These were from charts in the Handyman-In-Your-Pocket pocket reference book by Glover. ( 92W68.15 $10

) Actual hose tests were taken at one atmosphere. Pipe tests are for 60F temp, one atmosphere at sea level. Pg 631-647

Let's see if they're in Machinery's Handbook: Of course. Flow is covered on page 1751 of my '53 edition (14th). Several formulae are included. [Ascii won't DO that.]

Go for it. I did, too. ;)

The numbers seem a bit high to me, I have a 50 foot 1/4" air hose, and some

15 foot 1/4" hoses also. I notice the loss of speed and power when using a small air drill with the longer hose. Has any one checked these numbers out? I have a chart that I got off the net some where with figures for 1/2" and 3/4" hose deliveries at 50 feet if anyone is interested. Greg