Water Buildup in Pneumatic System?

Hello all, I’ve been building a test electronics board to prepare and practice for the new season. This is 4087’s second year and the first pneumatic assembly we’ve ever done. I’ve got everything working well so far and just wanted to ask if someone could put some rest to a concern of mine.

Every time I vent the pressure built up in the tanks by the compressor, I feel a lot of water vapor coming out. The amount of water I feel has definitely increased since the first few times I ran the system. Should I be concerned with this water? Is it harming the solenoid, regulators, tanks, cylinder, etc? If so, how can I get rid of the water that’s building up without having to take the entire thing apart every few times it’s used?

Thanks in advance for the help!

(And sorry if I missed any previous posts asking this same question, I didn’t see any when I searched.)

when you compress air you also compress the water in the air which is why there is water. more water means eathier there is more humidity or the compressor has been on longer. I have never heard of it being bad for the electronics

The moisture is simply condensate from the ambient air being pressurized. In indusrrial air systems this is prevented by havng dryers on the intake air to keep vapor out of the system, but in our simple systems there is not really any way of preventing condensate from accumulating. It is less of a problem in colder, dryer regions than in warmer humid ones. It will not cause problems as long as it does not become too excessive, but like any equipment your valves and cylinders could have some corrosion if they were left with the moisture for long periods. The best way to combat it is same way you prevent corrosion in other tools and equipment, with oil. A few drops of light oil (such as 3 in 1) introduced into the main supply line after the compressor will work its way through the system and keep internal parts lubricated and protect from corrosion. It also keeps your valve spools and cylinder pistons lubricated and working smoothly. Some problems teams experience with faulty valves are from the valves sticking due to lack of lubrication. We add a few drops of light oil into our robot systems 2 or 3 times a year.

Excess moisture in the air is really not a problem in New Jersey in January. i can see it being a factor in Louisiana though. As stated above it really shouldn’t cause any problems unless it gets through the lines as a liquid. More likely it will just collect in one or more of your high-pressure storage tanks. A few drops of air tool oil about every 2 or 3 hours of run time will prevent most of the problems you might encounter.

I personally would not use three in one oil because it tends to gum things up. But that’s just me.

Great! :smiley: Glad to hear most of my fears were unfounded. I’ll have to find some air tool oil somewhere and put a bit in the hose coming off the compressor. DonRotolo was right about moisture here in LA, especially in New Orleans.

I was thinking of putting some of those pellets that are found in those little packets that remove moisture from the air in the two main tanks as well, considering just how high humidity is year round here. Any thoughts?

Edit: BAD IDEA. :yikes: About ten seconds of thought after this post and it occurred to me that doing so would just be asking for one of those to get sucked up and lodged in a solenoid!

Thanks to everyone who replied!

If you find that the amount of condensed water is truly significant (we also are up north, so this hasn’t really been a problem), you may also want to consider this when laying out your pneumatic system - in particular, with respect to the vent valve.

For instance, vertical tank orientation, with the inlet and outlet on top, and the vent at the bottom (you don’t really want your air flowing through your pool of collected water). With multiple tanks, there isn’t anything that prevents you from having a vent on each.

Just make sure that you don’t vent onto your electronics :{D.

In industry ( i work as a maintenance tech at a local machine shop) we use this on every machine with a bigger more efficient unit on our central air station. so if you really want to be extra safe i’d infest in one or two especially in the southern regions, you don’t want to blow any pneumtic device due to corrosion. Its not only dangerous but it may cost you an event :]

We’re using two of the aluminum large volume tanks that were in the KoP last year and on FIRST Choice. They only have one inlet/outlet on the top and are currently mounted vertically with the inlet/outlet facing up. I’m wondering just how much water has built up. I’ll have to take one off, turn it upside down and see…

Cool, we’ll just have to see just how much water is building up over time. The compressor has really only been run for under an hour total, but there is visible air distortion caused by the water every time the vent is opened. I put my hand a few inches from the valve one time and a few drops of water formed on it.

Air compresses, water does not. That’s why when you compress the air the water collects in your storage tanks. I have seen large compressors that were not properly maintained where the storage tanks were half filled with water.

We had a warm humid winter this last year and we experienced water build up in the tanks of our practice robot for the first time ever. It wasn’t a lot of water but I was never the less surprised by it.

If you are experiencing this because of your climate you should have a way to easily remove your tanks from the robot so they can be drained. Keep the inlet pointed up so the water can collect in the bottom. The plastic tanks from AndyMark are great for this because they are held in by clips and are easily removable.

Generally most pneumatic components are designed to take a little bit of moisture. There is a reason that cylinders are mostly made form stainless steel.

Water doesn’t compress much, but it does compress.

All those evil 3s --> http://en.wikipedia.org/wiki/Properties_of_water#Triple_point --> WATER GAME!

While we’re on the topic, I’m looking for a good auto-drain setup for our shop’s air compressor, if anyone has one to suggest.

mc-master hase some

On the topic of valves sticking, we stored our all of our old robots in a shed with the valves on them, and we’ve only been able to get about half working by taking them apart and cleaning them out.

There are some tiny parts in a solenoid valve. I hope you were very careful about cleaning them, just as though you were working in an operating room (maybe surgical masks are overkill). Perhaps a very light film of air tool oil would help.

Most solenoid valves have a manual override; maybe a tiny button to press or screwdriver slot to rotate. This can help determine if the problem is electrical or with the valve spool.

Solenoid valves have a minimum operating pressure. Did you check that? Some are 24V. If you send 12V to a 24V coil you might see the LED light up but the valve wont work. This has frustrated many teams until they checked their valve specs.