Underground Compressed Air

[zuiko]

Interesting, I hadn't even thought about moisture but I can see that being a big problem since the line would be the lowest part of the system. I suppose I could figure out where the low end is and put a valve in there.

 

[CTyler]

If this was a hose then connect a shop vac to one end and drop a ball bearing in the other. Should get most it. If this was a conduit then run a hose thru and suck it out. Or dig a manhole and put in a valve.

 

[ns_in_tex]

I think the moisture falls out of the air as it cools and if possible, you should try to accomplish this before the air enters the distribution line.

 

[sfcsarge]

As far as moisture is concerned, you can get yourself a water trap to use right off your compressor. Just open a valve on the bottom and drain the water. You can even get an automatic one to blow water out at regular intervals. As a matter of fact, it's not a bad idea to get one for the drain valve on the compressor itself to keep water from building up in the tank. We use them all the time at work and unless you have an extreme problem with water, they work pretty good.

 

[fractal]

I looked into running air line around my shop a while back. Interesting the gyrations people have to go through to keep water and corrosion out of the lines.

I would use black pipe and put a water trap at each end. It seems conventional to run the pipe at full tank pressure with only a filter between the compressor and the pipe and to put filter-regulators or filter-regulator-lube units at each point of use. A water trap is nothing more than a stub of pipe going straight down with a valve at the end. It does mean running the pipe at a slope and having a 6-12 inch pit at either end for the water trap.

 

[BIGUN]

</font><font color="blue" class="small">( I think the moisture falls out of the air as it cools and if possible, you should try to accomplish this before the air enters the distribution line. )</font>

Yes it does and you should, but it would be difficult for the home user to accomplish this since the air will continue to cool as it enters the buried line outside, especially in the winter.

At the plant we run our air through a refrigeration unit to condense the majority of the moisture from the air, then to reduce the dew point to a value much lower than the lowest anticipated ambient temp we run the air through desiccant driers. This will lower the dew point to somewhere around -50 deg F. This prevents water (ice in the winter) from forming in the air lines which supply air to operate controls within the plant. Without all this expensive equipment, water will form in your underground line. /forums/images/graemlins/frown.gif

You can run whatever type of pipe you decide on with a slope away from the source of air with a "low point" drain coming off the bottom of the pipe close to where it comes back up out of the ground. The valve on this drain doesn’t need to be below the pipe. The drain line can be routed to come up above ground level with the valve installed in a convenient location. Use a smaller line (1/4") for the drain than the main pipe. I like the ball valves for air lines. The line can be blown down daily or as needed.