Pneumatic Tanks
 

Our team has never done pneumatics before, does anyone have any tips? Also, how many storage tanks are we allowed to have on the robot?


Thank you,
Austin

Re: Pneumatic Tanks
 

First tip: read the pneumatics rules. Then move on to CD-Media for all your presentation needs.

There's no hard limit on how many storage tanks you can keep on the robot. Just remember that the more tanks you have, the more time you need to run your compressor to refill them.

Re: Pneumatic Tanks
 

The first tip is don't be stingy with the teflon tape. Make sure that all of your connections are sealed well, the last thing you want is to have to find a leak. Just do it right the first time, even if its not as quick as you would like.

Secondly, keep your tubes clear. If it's your first time, you will most undoubtedly have problems somewhere. Keep the tubes well organized like a good electrical system so that if you do have to deal with a problem you will have an easier time of finding it.

I second reading the rules. This will do nothing but help.

Good luck!

Re: Pneumatic Tanks
 

Cut the tubes square. If you cut at an angle at all, you're inviting air leaks that may be pretty hard to find.

Re: Pneumatic Tanks
 

We have found that the clear tube is better, as some teams have had other tube, specifically blue, that crushes and pops out of the fittings. Also, plastic air tanks and mini compressor for the win.

Re: Pneumatic Tanks
 

Pneumatic's are fairly simple. The plastic tanks are the best, and yes make sure the pipe is cut square!! That is so important,make sure you use the right valves on everything and neatness is the key to the tubing or it just gets in the way:)

Re: Pneumatic Tanks
 

also the wires from the solenoids dont let the wires get to close together they will begin to melt and cause them to fail it happend to my team in 2011 worst day ever

Re: Pneumatic Tanks
 

Get acquainted the terminology of pneumatics. I'm assuming most of the team is unacquainted with pneumatics in general. There's a decent amount of new vocab when dealing with pneumatics, but knowing them gives you an advantage when you're reading about part information or looking for help.

Also, be creative! There's lots you can do with a piston if you think hard enough. Take advantage of its length, speed, power, etc.

Re: Pneumatic Tanks
 

Is there any way to calculate how many times a certain tank can actuate a certain cylinder? Like an equation based on size of piston, force for the piston, size of air tank, pressure of the air tank.

Re: Pneumatic Tanks
 

Yes there is! I recommend you read the Pneumatics for Newbies (pdf link) paper on Team 358's excellent Pneumatic Resources page.

Re: Pneumatic Tanks
 

Regarding Teflon tape, you actually do want to be stingy. Just wrap it once around the threads (a couple millimetres beyond a full turn), such that the cut end of the tape is not bunched up by the tightening of the fitting. Leave at least one thread un-taped on the open end of the fitting.

The tape isn't the sealant. Instead, it acts primarily as a lubricant. NPT threads are tapered, and as such, it's the faces of the threads that actually make the seal when tightened properly. (Other types of threaded connections like JIS may not be tapered, but instead depend on other surfaces for sealing.) Excess tape increases the chance that a piece will be squeezed out of the joint, and break off into the fluid stream when pressurized. You don't want pieces of Teflon clogging the tiny valve pilots.

Re: Pneumatic Tanks
 

Familiarity with the Teflon brand of fluoropolymers has led to the practice of referring to PTFE-based thread seal tape as "Teflon tape". DuPont, owners of the Teflon brand, does not manufacture thread seal tape.

Re: Pneumatic Tanks
 

Does their raw PTFE get used in its manufacture?

Re: Pneumatic Tanks
 

From experience, I find that this tends to depend on the quality of the tape itself. The higher quality (i.e. thicker and more durable) it is, the less wraps you'll need; the lower quality it is, the more you'll need.

One thing to remember is to wrap the tape in such a direction that tightening the threads continues to stretch the tape, rather than make it bunch up.

Re: Pneumatic Tanks
 

Nor do you want anything else in those pathways. If the ends of your tubing are open or have spent significant time open, they may already be contaminated. Every time you cut off a piece of tubing for use, you should close off the end of the unused roll to prevent stuff from getting in there. I wince every time I see a piece of open ended tubing in the bottom of the parts tote. Why take chances?

Re: Pneumatic Tanks
 

Looks like the answer is no. This is from the Dupont website:

If somebody offers to sell you “Teflon tape” when you need plumber tape (or thread seal tape), they are wrong, mistaken or — worse — trying to mislead you. To help you make an informed purchase, you should be aware that no plumber tape is authorized by DuPont to be sold as “Teflon tape”.

Re: Pneumatic Tanks
 

Less joints is always good. McMaster (and others) sell some t-joints that are threaded on one side and quick connect on the other sides. Being careful with your joint and connector selection will let you reduce the number of joints in general which leads to more reliable pneumatics all around. I cringe at all the little stub joints used to bridge between fittings. Every one of those is a potential failure waiting to happen.

-Mike

Re: Pneumatic Tanks
 

Do not consider the pneumatic quick connects to really act as quick connects, at least not on the final robot. The tubing and even the connectors start to wear with repeated insertions. Try to limit the number of times you disconnect and reconnect these joints to avoid creating a lot of small leaks that are difficult to find. On the finished robot, it is not over cautious to re-trim the ends of the tubes each time you remove and reinsert them. If the tubing gets too short replace it completely. Many students seem to want to pop these connections on and off way too much for a trustworthy connection.