the space i moved into has pvc (pressure pipe SCH 40 600psi) through out the shop in every room with drop offs and drains. Really nice and convenient all i have to do is set up my new compressor and hook it up to the existing line, right?
well that was the plan. But after reading some of these comments in this forum http://www.woodweb.com/knowledge_base/C ... ystem.html
I am beginning to rethink the idea of using the existing line. What a shame though all that work already done and the material, everything is ready to go.
Instead of having 2 to three drops in everyroom (4) i think i am going to run copper and have fewer drops
has anybody out there used pvc for air lines? if so am i being to much of a ninny?
I am not a fan of PVC, too risky. It gets brittle with age, and the shop is an environment that begs to have an incident.
Black pipe is a pain for a number of reasons. First, it's annoying to install, second annoying to add a drop. But most of all, it rusts and corrodes with moisture and with mess with your tools and potentially your finishes if you spray finish.
Copper is my choice, a tad expensive, but very easy to add lines and such.
I'm also curious about whether you could use PEX for compressed air. I wonder how it would age- especially given it's sensitivity to UV light.
I found the installation and additions for black pipe are not any tropuble at all. I went to HD and bought a variety of pipe fittings and lenghts. With all the fittings in stock, any installtion, or addition is easy. I was going to return the extra's, but at the cost, I just decided to keep them. Drawer number 24 A is now designated as the black pipe fittings drawer. As far as rust goes, I have never had a problem.
The pex option is one to consider. I helped NOJO rn it in his shop. very easy to run. PSI rating is a little close to what is recomended for the pex. I dont think it is too much of an improvement over the PVC.
there will be water in the lines no matter what. you can use a dryer, filter ect.. but moisture will build and enetually if you have black pipe they WILL rust. I know how often you drain your lines douglas
GG, I like the idea of using the pvc at a very low psi, so you can have air to "blow off" all around. Then run a couple of high psi copper lines for all of your other needs.
copper vs black iron, definately not pvc, i used black iron and installed drain drops at several low points in system and employed a air dryer (my edgebander, widebelt and hand sanders all depend on dry air, not to mention spray room) but this still is not fool proof below is copied info for read
Why drains are necessary
Water migrating with air into valves, cylinders, and motors will wash away lubricating oil. Stripped of adequate lubrication, machines run sluggishly and lose efficiency. This is especially true of miniature components and tools, where slidingsurfaces are small, so wear can accelerate. In addition, moisture wreaks havoc on motors and bearings, resulting in higher rates of equipment failure and, therefore, higher maintenance costs.
Some applications cannot tolerate any water and or oil in the compressed air stream. These include spraying of paint, powder, and other coatings; food handling; and similar processes. In instrument air systems, water will tend to cling to small orifices and collect dirt, unleashing erratic operation or failure of sensitive devices. In pipelines, moisture accumulation at low points reduces the carrying capacity of the line.
Eventually, air flowing past a pool of accumulated water will pick up water and carry it along at high velocity, potentially damaging anything in its path. In extreme cases, a slug of water can be carried into a tool and freeze or even burst a pipeline if ambient temperatures fall below freezing.
Clearly, quick removal of water and oil is essential to the efficient operation of a compressed air system. Scale and sediment in piping may interfere with the drainage process. Refer to the box at right for details.
Drainage methods
Condensate drains operate either manually or automatically.
Manual drains purge liquid when someone periodically opens a valve manually. Not only is this method labor intensive, it continually wastes compressed air — as well as the energy to produce it. A valve manually opened will be left open until air blows freely. However, an operator often delays or forgets to close the valve, losing precious air or gas.
Automatic drains seldom are provided on original systems. However, subsequent installation of automatic drain traps will significantly reduce energy and maintenance costs.
Water collected in separators and drip legs must be removed continuously without wasting compressed air. In the absence of drain traps, drainage often is accomplished by periodically opening valves just a crack or leaving them slightly open to drain constantly. In either case, the valves are opened far enough that some air escapes along with the liquid.
To eliminate this waste, drain traps should be installed at appropriate points to remove liquid continuously and automatically without wasting air or gas. For good overall efficiency and economy, the trap should also provide:
trouble-free operation with little need of adjustment or maintenance,
reliable operation, even when dirt, grit, and oil are present,
long operating life,
minimal air loss, and
ease of repair.
Automatic doesn't mean forget about it
Many older compressed air systems still use manual drain valves. This present two problems: Someone has to open the drain, and a lot of compressed air is wasted when that happens. A broad variety of reliable automatic drains is available to eliminate both of these problems — often capturing a quick return on investment via savings in compressed air cost.
A drain may not function properly if the compressed air is contaminated with dirt. Half the job is getting the contaminant into a physical state so it can be removed; the other half is removing it. Inlet temperature to the compressor can also cause problems. In hot weather, excess oil may be entrained in the compressed air. However, when temperature drops, the effluent of water combined with oil can become more viscous, or even gummy, making it more likely to clog drains.
In many cases, a drain failing in the open position can result in low pressure in production because not enough compressor capacity exists to supply production demand and the loss through the drain.
If solenoid-and timer-type drain valves are applied properly, and personnel-are disciplined enough to periodically adjust the individual valves, everything works as it should. Unfortunately, drains generally are not considered important enough to warrant regular monitoring. Consequently, the result is system contamination, wasted energy, or both.
When they are working, inexpensive drains get rid of effluent. However, they waste compressed air in the process, which wastes energy by keeping compressors from unloading. Drains can also be a significant contributor to fluctuating system pressure. Periodic adjustment of these drains overcomes these problems.
Another type of malfunction can occur when air bubbles become trapped in the drain line. When a slug of liquid covers the trap connection port in the bottom of the sump, and there is not enough liquid in the trap to actuate it, an air or gas bubble becomes trapped in between. The vent line is supposed to allow the gas bubble to pass.
Most drains have a vent connection, but virtually none has vent lines installed. When the gas bubble is trapped, the liquid backs up in the sump, and carry-over occurs. Opening the pipe connection slightly to the drain relieves the bubble, and nothing appears to be wrong. The trap connection is reassembled until the next time a gas bubble becomes trapped.
Because most drains don't accommodate dirt or rust very well, the size of the through-porting of the drain largely determines if the drain will become plugged. If plugging occurs, don't look for a replacement drain with larger porting. Instead, question why substantial amounts of dirt and rust are present.
In compressed air systems using non-lubricated compressors and ferrous-metal piping, expect lots of rust and pipe dirt to be present. To alleviate this problem, alternative piping materials or piping with a coated ID can be used.
All drains require inspection and periodic maintenance. More sophisticated drains have failure lights or audible alarms in the event of malfunction. However, these indicators are not a substitute for maintenance that prevents malfunctions in the first place.
This information was excerpted from the 2004/2005 Fluid Power Handbook & Directory.
A shop I used to work at replaced all their nightmare PVC a couple years ago. They did it (40,000 sq ft shop) with aluminum tubing as the price was slightly better than a copper option. The fittings are all push on o-ring type, so basically its super easy to install. No rust... No torch/solder/flux...
No problems as yet.
The fittings came from Parker if memory serves.
Definitely nice stuff, and I'll be looking in to it when I do my new space...
