I need to create a "chase toy" for a zoo mountain lion. The general gist is that there will be a long, clear PVC pipe going through the exhibit. I want to use compressed air to send a fake prey item through the tube to encourage hunting behavior. The air source should be able to push the prey item from both sides. If possible, I'd like to have 3-4 separate pipe lines that can be activated separately from one another. How would you go about this? An air compressor with pneumatic solenoids could work but from what I've read, air compressors can be unsafe when used with PVC. The other option would be a vacuum but as far as I know, the vacuum would only be able to control a single one of the tubes. I will take any advice or ideas!
Why would compressed air be unsafe? Just determine the maximum safe pressure for your pipes and dial the regulator down to some pressure less than that.
For fun, look up the problems that the original vacuum railway had. That was a long time ago when manufacturing was not as precise and a defect in the pipe could be dangerous with high pressure. It turned out to be a spectacularly bad idea pretty quickly.
Well, you're going to need some sort of compressor. This looks like you'll want more air volume and less pressure than typical auto shops or woodworking shops use. if you don't use high pressure, it'll be plenty safe in PVC. If you use pneumatic valves, they'll have to be big enough to handle high volume. Or, you might be able to use fans directly if you get some with high enough pressure.
Interesting project! And welcome to the Arduino forum.
I have never seen transparent PVC pipe. Can you supply a link to what it is and where you get it?
As far as sending an object either way on piping, you will encounter problems with joints connecting one pipe to another unless the ends of the pipes are tapered so the object won't catch on the ends. Have you done any PVC plumbing?
Paul
How about clear monofilament line instead?
Thanks for all of the responses!
I just found out that I have access to a compressor that will allow me to control the output pressure. My plan is to hook the compressor to a manifold that gives me 6ish outputs and then have each output go into a solenoid. Each "prey track" will be connected to the air supply on both ends so with the solenoid, I can have the "prey" (stuffed animal) go down the tubing in both directions. Then I'll have three "prey tracks" which will use all 6 outputs and allow me to vary the location of the chase. I apologize if I did a poor job of explaining all of that.
I have zero plumbing experience unfortunately so I'm totally winging it. Here's the pipe I'm looking at:
dougp:
There are people who make these things: Kelly Tube Systems - American Pneumatic Tube System Company
I see metal tubes with some polycarbonate plastic parts. Nowhere is PVC tubing mentioned.
Paul
JGolden8383:
Thanks for all of the responses!I just found out that I have access to a compressor that will allow me to control the output pressure. My plan is to hook the compressor to a manifold that gives me 6ish outputs and then have each output go into a solenoid. Each "prey track" will be connected to the air supply on both ends so with the solenoid, I can have the "prey" (stuffed animal) go down the tubing in both directions. Then I'll have three "prey tracks" which will use all 6 outputs and allow me to vary the location of the chase. I apologize if I did a poor job of explaining all of that.
I have zero plumbing experience unfortunately so I'm totally winging it. Here's the pipe I'm looking at:
That, as you can see is "tubing" not "pipe". I have used the smaller diameters for air in various pieces of equipment. It is very durable and may be purchased with fibers molded in to give it more strength and will work with higher air pressures.
If you plan to lay it on the ground, it will work for your project. Otherwise it will sag from every support point. Similar to using a garden hose.
Pau
With a little bit of careful design you could move an object in a pipe with a very small pressure differential.
...R
I have used this:
Paul_KD7HB:
I see metal tubes with some polycarbonate plastic parts. Nowhere is PVC tubing mentioned.Paul
I only meant that there are companies who design and build tube systems and that various capabilities and specifications can be included, not that the named company is necessarily the correct match for this project - although they could be : "Kelly Systems provides custom as well as standard pneumatic tube systems for its wide range of customers."
Someone who does this for a living would also be a good partner to have in that they'd be able to locate materials, provide specialized/custom parts, and, importantly, offer general expertise in this area.
Hi,
Don't forget the amount of static electricity you will be producing.
One of our national supermarkets uses a kelly type pneumatic system, the pipes always look dirtry/grubby due to the static attraction of dust, each checkout point has a gnd wire from the pipe going "somewhere".
If you are pushing the "chase toy" through a decent sized pipe, you will need to check if you can supply the volume of air needed to push the full pipe length at the required pressure for the speed you want to try for.
You may need a large diameter "firing" valve and Accumulator to push the toy across.
Or a light weight tumbling "chase toy" such as a ball.
Tom.. 
After public visitation hours, just put a couple of live rabbits in the enclosure instead.
Much easier, much cheaper and much better for the mountain lion.
Maybe water rather than air.