I have a 5hp, 60 gallon tank, 20cfm(?), 2-stage air compressor and have a regulator/seperator mounted to the tanks exit line. When sandblasting, I'm still getting a lot of moisture through the line. My main line (1/2" copper pipe) goes to the center of my shop and splits into two major 1/2 lines - one to an outside quick disconnect and the other to my blasting cabinet. I had a rather cheap seperator at that point, too, which doesn't seem to be doing a whole lot and is now leaking. I can't afford hundreds of dollars on one, but is there anything available at under $100 that would be effective? Thanks, -Bob
how does the main pipe run....is it level, or angled? what drains do you have in the piping system? I don't have any moisture problems with my sandblaster, it's at the end of a long run that has several drains along it. I have no moisture separator at all. Although living in AZ probably helps.
I've seen threads on the garage journal showing manifolds built to cool the air and collect water before it gets away from the compressor. Thinking about building one myself. Here's one thread -> http://www.garagejournal.com/forum/showthread.php?t=141247
Be sure to drain your compressor tank daily. Where I am now its not to humid but I still have to do it. Does your compressor have any type of cooler between the pump output and the tank. If you add one it will keep the tank temp. lower most of the moisture will accumulate in the tank and not downstream in the lines. I picked up a large seperator/regulator at a swap meet and attahced it to the side of my cabinet. The larger the better to keep air pressure up. It has a clear bowl so I can see if it needs draining.
what you need is a dryer . Dryers are expensive and not always an option. If you can take the piping and make sure that all the lines are slopped at least 1/2" for 10" you can make your own drain with two ball valves and a small run of pipe. you put a t in the line and drop it down. one ball valve just below the line and another a foot or so below. keep the top valve open to catch the water. when you need to drain it close the top and open the bottom. very little pressure lost and all the fluid. This is the same idea used for dry sprinkler systems. cheap and easy but not the best method. be sure to drain your tank regularly
There's a lot of science but its pretty easy. Line should go up out of compressor then pitch down to the end of the line. Use a T filling at the compressor with a dirt leg drain below where it goes up. You need about 50' of line so the air can cool and drop its moisture , copper coil would work too. But the coil needs to be mindful of the pitch, laid horizontally so as not to make vertical loops and water traps.. The take off for your air supply should come off the top and return down with a 180* turn. Your inline separator would go at the end of this. Just down from the top take off should be an elbow 90* down with a drain for the line. Pitch to this drain is important.
Here is how I did mine. Black pipe out of the compressor, up and down twice with a ball valve at the bottom of each. The black pipe cools the air fairly quick even in hotter temps and the water collects at the bottom. This removes about 85% of the water, a water seperator is used at the end. I drain the traps as needed...works good.
All industurail sized air compressor have aftercoolers which drop the temperature of the compressed air before it enters the air reciever to remove moisture. With smaller shop type air comressors the tank acts as the cooler to remove moisture (refrigeration drying). If you're running the compressor continously it doesn't have time to cool and remove the moisture in the tank. Therefore, moisture (in gas form) enters your lines and as the air cools on the way to your tool moisture condenses and builds up in the air stream. There's a bit of science behind it but the mechanism for removing air by cooling it is to drop the temperature of the air below the dew point of the air at it associated pressure. You can add dessicant type filters after refrigeration drying to dry the air even further. Do a Google search for diy compressed air refrigeration drying and you should see a few ideas. I thinks it's best to do the refrigeration drying before the tank to limit moisture in the tank, also, then your dryer is upstream of the compresser unloader valve therefor it won't have pressure in it when the compressor is off. Here's a write-up a guy did. I'm not too keen on it but it gives the general idea: http://www.rocketcityrockcrawlers.com/memberstuff/doc/el cheapo compressed air dryer.pdf I saw one where they coiled line in a trash can then filled it with ice water. That would get your air really dry. Having just water in it I think would work well to, even if you just trickled tap water through it. http://www.shopfloortalk.com/forums/showthread.php?t=5934&page=1&pp=10 I think the post above mine is a good simple idea. I don't know where it's located but I would have it before the tank. But even simpler as some noted, a water trap after a long run of pipe is essentially the same idea.
That's because the water is still in a vapor state. The separator only works on condensed water. You need to run at least 20' - 30' of black pipe to cool the air before it hits the separator. 50' is best if you can make it happen. http://www.tptools.com/StaticText/airline-piping-diagram.pdf
I think your 1/2" line size is part of the problem. If you jumped it up a size or two the velocity would be lower and less likely to carry over moisture. The larger pipe will also reject heat better (especially copper), causing the moisture to fall out earlier.
i use 3/4 pipe went about 25 feet went into a 1 1/2 " pipe droped down about 3 feet then over 3 feet then back up3 feet then back into 3/4 " pipe with a drain valve at the bottom of the drop drier at the end of the line so far i have had no problems with water
The plumbing recommendations and draining the tank regularly are the cheapest measures. The small separators and combination separator/regulator units can so a little, but they are not a cure. A separator that refrigerates the air is the best, but those aren't cheap.
Thanks for all the input. You've given me food for thought and now I have to do a little more research.
"Teeing" off your main line by running up first, then down (180 turn) helps - TP Tools has a good diagram in their catalog. I bought a refrigerated dryer for painting, they're expensive new but I got a used one for $200 with a bunch of pneumatic cylinders and Bimba stuff in Las Vegas. If you check with NAPA, they have a drain valve that is made for truck air tanks that has a cable attached that you pull to drain it - no bending over or crawling around to drain (picture).
X two on this one. The biggest mistake people make (hell, I did it) is hang a filter/separator on the end of the compressor. Regarding after coolers, Harbor/Flake makes a refrigerated unit for around 4 bills (last time I looked) Some say it works OK. Or check out local listings. I bought a fan powered air cooler for $120 bucks. Also, I know this is pie in the sky but commercial/industrial compressor tend to run a lot cooler than home garage units. To get the claimed output, the home units spin four times as fast and four times as often as commercial units. They pump a lot of heat. The heat is what condenses into water.
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