pic: T-Shirt Cannon Bot Concept WIP

[MrBasse]

The valve we run is a check valve run in reverse. We move the whole valve and engage it into the shell to release the valve. Clear as mud? I can try to get some pictures that will be rightside up this time to help out if not.

We had to do a little machining (i.e. sanding and filing) to make a threaded end that would fit inside our valve.

Brass with pneumatic actuation

Brass

We actually run a plastic valve that has a burst rating of 200 psi and is rated for gas to 100 psi. I don't remember where we got it from though.

Our tank is a hot water expansion tank like this. Yes it is for water and not for gas, but we are running at less than 20% of the rated pressure and it is a steel tank that has a safety vent built in.

We have had no issues and pressure tested one to 130 lbs prior to using it by filling it and draining, repeating then using some force to deform and filling and draining again. No leaks, no failures, and no worries with 10-30 psi being contained.

The benefit of how we built ours is that we use a cylinder to push the actuator to release gas. If we pressurize over 30 psi the regulator on the cylinder won't allow the cannon to fire or engage. It just hisses a little and reminds you that you are trying to do more than was designed for.

[Bruceb]

706 uses a pony scuba tank
Last about 30-40 shots.
The tank cost us something like $120 but with that we get free refills. We had to get a supplier to build a custom valve to handle the 1/8 hose. That feeds into a storage tank that holds
60psi. We usually shoot at something between 20 to 40 psi.
With this set up and how fast the scuba tank recharges the storage tank we can shoot all 10 of our stored t-shirts in something like 15-20 seconds.

[DonShaw]

Look on ebay for some 12volt air solenoid valves, I found ours rated at 215 psi and 3/4 npt threads. Fast open and close and no leaking. Cost was about $30 each.

[Kyle Butzerin]

Originally Posted by DonShaw

Look on ebay for some 12volt air solenoid valves, I found ours rated at 215 psi and 3/4 npt threads. Fast open and close and no leaking. Cost was about $30 each.

A 3/4 is good but our team really wanted a one inch. The school district is not allowing us to use CO2 Canisters of any type, they are already edgy on us making a tshirt cannon robot. I've having a lot of trouble finding a high pressure solenoid, so should we settle with a 3/4"?

Once again, thanks everyone for the feedback, but i need to identify a list of objects (Tank,Hose,Solenoid,Barrel) which could be all be strung together and put on a robot. we have 20 new members waiting on the design group to finish the model for this bot.

Thanks!