Water in compressor line.

[BKinzey]

I have a 20 gallon portable. When running for any length of time it really starts to condensate. I get what I would consider to be a lot of water out the hose which is about 75' and rubber. Enough that it begins to dribble out my air tools. I have a water separator on it but I've never gotten more than a few drips out of it.

I oil my tools every day I use them and have started to oil them before I put them away. I'll put a few drops in and reconnect the hose and give it a quick spurt to spread the oil. I'm still concerned though.

I might change the water separator to see if that helps. What's a good one for about $50?

I'm also considering attaching a 10 gallon tank for more air and wonder if that will help for water. If I do should I attach a secondary water separator to that tank and if so should the secondary filter go on the inlet or outlet of the second tank?

 

[MTChevy]

I know my water separator does an awesome job until it fills up. Not a single drop of water is noticed in my tools till the separator is full of water. Maybe yours is just bad. I think mine was 30 bux at sears. Its craftsman. Hope that helps

 

[Muddytazz]

We've got a water separator on our 200 gallon tank from Harbor Freight and have never had any issues with water in our lines or out the tools. Sounds like you either have a bad unit or you have water in your tank and you need to drain the tank.

 

[chevyin]

How did you size your separator? When it comes to separators, bigger is not better. Compressed air water separators work by spinning the air inside the bowl of the separator, the centrifigal force deposits the water on the inside of the bowl and it runs down the sides to collect in the bottom. Because of this, you have to buy a separator that is matched to the volume of air you are using. It is generally better to have too small a unit than too big. Also, the reason you notice an increase in the water after you use the air for a while is that as the compressor compresses the air it heats it up. Water vapor in the air is relative humidity. The higher the temperature and the pressure of the air, the more water it will hold. As the air pressure drops and the temperature decreases, the excess water condenses out. The only true way to dry the air is to mechanically cool it. This can be done by running it thru a high pressure radiator, or a refrigeration unit. Also, many separators are auto draining. You can tell the auto drain models by the tube fitting on the bottom of the unit.

Adding an extra tank will help your water problem, because with extra volume in the air reservoir the compressed air will be in the reservoir longer. Being in the tank longer will let it cool more and more water will condense out in the tanks. You will simply have to drain the tanks more often. Adding additional separators will probably not help.

Sorry for being so wordy, but I hope this helps. P.S. You will have solve your water problem if you plan on doing any painting. Water and paint do not mix!

 

[BKinzey]

I bought the compressor used and it came with a separator. Certainly didn't look cheap but doesn't seem to work.

I also got a cheapie sand blaster and picked up a Harbor Freight separator and put it on the sand blaster tank. It works pretty well. I had the separator at the tank and the HF on the blaster. I'd get lots of water out of the HF and only a few drops out of the one on the tank.

So how do you size a water separator?

I pull the water drain on the tank at the end of each day of use.

 

[chevyin]

The inlet and outlet on the separator should be the same as the line size you are using. Never bush them up or down.

The separator at the sand blaster would have the advantage of the lenght of the hose from the compressor to the blaster. The hose will act as a cooling line. The cooler the air, the easier it will be for the separator to work.

I am a retired mechanical engineer, worked in machine design that included air supplies. If you wish to discuss the particulars of your application, PM me with your phone number and when you are available and I will call you.

 

[BKinzey]

Thanks Chevyin, I might take you up on that if I can't figure it out.

The separator I got with the tank is a Milton and is labeled 1/4" in & out.

So if I use my 10 gallon portable tank as well I can put a 25' hose between the two and use the Milton upstream, or on the inlet side, of the portable tank. That should cool the air enough for the Milton to work and since the portable tank is without a water drain, at least I don't think so, this should minimize any water in the portable tank. Correct? Or confused?

 

[chevyin]

Sort of confused. Water separators work on centrifigal force, while cooling the air reduces the amount of water the air can sustain as a vapor. Cooling the air will produce condensation, with or without a separator. Water separators work better when the air is cooled because cooler air will have a higher relative humidity, therefor making the centrifigal forces more efficient.

Because of condensation, you must have a drain on the secondary tank, or it will fill with water either today, tomorrow, or next week. If it doesn't, it is not doing anything to help dry the air. However, you do have a drain on the tank. Portable tanks normally have the inlet bung on the top of the tank for convenient filling, however, air does not have to go in the top. Simply mount your tank upside down and put a tee at the bung. On the bottom side of the tee mount a valve and now you have a drain. Between the tee and the valve you will have to make a reservoir out of something like larger diameter pipe or something like that. The reservoir has to be big enough to hold the amount of water collected between draining, or the water will simply be blown down the line.

There are many ways to dry compressed air. The best way by far is to cool the air, but what you will have to do will be determined by several factors. Most importantly is the weather conditions at your shop, but others are the amount of air you use, the cost of electricity(for mechanical cooling), and the application for the compressed air. If you only use the air for air tools, then careful oiling will do fine. If you never use the system for painting, then you can get by fine by eliminating what water you can without going to too much work and money and simply adding an oiler to the system. Oilers are not expensive and can be adjusted as to how much oil they add. Just remember, however, that once you put oil in your air hose, you cannot use that hose to paint with.

Hope this helps.

 

[Greg72]

The more obvious problem (at least to me) is that you make no mention of using anything but rubber hose off the compressor.

Most well-engineered air delivery systems use black pipe to transfer the pressurised air to around the shop, and then at the last moment, the pipe is terminated to a fitting that your airhose can connect to.

The problem is that rubber hose is a great insulator, so the heat doesn't dissipate, and the moisture stays in suspension with the air.

By using black pipe, you get a cooling effect of the recently compressed (ie. HOT) air and the moisture will begin to condense out. The black pipe is typically run at a slight angle to allow water to run out of the horizontal pipes and down to a petcock near the floor that can be drained occasionally. Additionally, the "taps" off the main black pipe maniford typically go vertically, to prevent them from picking up any residual moisture from the pipe.

The water seperators should typically be installed as close to the END of the air line as possible which will help to catch cooler air, and extact the moisture when it's easier to do.

If you do a quick Google search you can probably find a good schematic drawing of how to set up a proper air distribution system for your shop. Smaller compressors run hotter than larger ones (longer duty cycles) so water tends to be more problematic....... I used to run a 25 Gal Craftsman 110V compressor through 50' of rubber air hose, and could never figure out why the air was always so wet....... so, yeah....I've been there.

 

[chevyin]

Greg, I absolutely agree on what you suggest, especially the loops on the tap lines. In the past on systems, I have used copper lines inserted into the aluminum heat sinks made for under floor radiant heating systems. The whole idea is to cool the air.