Pneumatic questions, sorry!

[geeza]

Alex, we all use liquid CO2. George was referring to the fact that in the main bottle it will be liquid but by the time it reaches the ram it should be gas. Otherwise the whole system will freeze, nothing will work. What Kane said is exactly correct large buffer, short pipe work.
That dry powder will be ok for a buffer at that pressure yes but not suitable for a main tank.

[Liftoff]

If your system is an LP one, the most important thing is to have the least restriction possible from the buffer to the ram, that means the shortest, straightest and largest way possible, all the rest does not matter much. On a FW I would try to use 1/2" fittings if possible, couldn't manage on mine so I compromised with 3/8" fittings...results look encouraging!
Like Ed said, that tank is ok for a buffer, but surely not as a main.

[Eventorizon]

What if you did something like this...
Custom 50x100 Cyclinder to Buffertank link.jpg
With the pneumatic cylinder we have you can take the end off. If you took that off then replaced it with a custom valve that had a diameter that was the same at the cylinder bore, I am guessing that this would technically be the best possible set up.
You would weld a custom mount to the side of the tank then have a solenoid inside to activate the valve itself.

[Max]

That would be ideal but you will struggle to find a valve with that kind of bore ad if you made one it would be very heavy and would need a lot of power to switch it. You could also blow the end cap of your cylinder off by making the piston go too fast but I've never heard of that happening.
I would just use woody's QEV system as it is the cheapest way to get good flow. For the price of all that custom work you might as well go full pressure. also if you have access to lathes/milling machines (especially if they are CNC) it is not very difficult to make a high pressure ram.
Also, if this is for a flipper there is a maximum amount of flow rate you need due to how quickly you can accelerate the other robot. If its for your spike weapon then there will be a maximum due to the mass of the spike

[Eventorizon]

What is Woody's QEV system?

[Max]

http://www.teamonslaught.fsnet.co.uk/pneu.htm

[Liftoff]

I run a similar set up... have a look at the last post on this page...on this thread there are listed all parts you'll possibly need!
http://www.fightingrobots.co.uk/thre...d-diary/page12
Its quite simple and its relatively cheap to build. The most important thing is to have large bore fittings and short pipework...in my setup I connected the QEV directly to the ram, so losses due to length of pipes are the minimum possible.

Edit: I found a photo of the semi-assembled set-up

[Eventorizon]

That is perfect! Also that 4 bar is basically what I was aiming to make... except its already been done. Well if I can get a 4 bar going it will be the first in the UK.

[PJ-27]

There's already a LP pneumatic 4 Bar, can't remember who made it. I believe there was also a FP, called Flick or something?

[razerdave]

Yeah, Flick was a HW from the Supernova team.

Not sure there is a pneumatic 4 bar flipper, there's been a few electric ones though. Are you flipping from the front bars or back bars ?

[typhoon_driver]

It was pneumatic

[Eventorizon]

Flipping from the front. I've been examining various setups; Ziggy, Biohazard etc. Now this one from Aus.

I am just not sure what is the best kind of set up on a 4 bar. I downloaded that 4 Bar calculator but it doesn't mean much to me.

[razerdave]

I meant to say no FW pneumatic 4 bar flippers. I know Flick was pneumatic .

[Shakey]

I built one but never actually made it to competition, I have since nicked the parts out of it for other robots.

[Max]

Hi,
Does anyone know if a 1/2" NPT connector will screw nicely into a co2 nut? Im thinking of buying a hydraulic elbow to go from 1/2" BSP from my paintball bottle to 1/2" NPT. this seems like the easiest thing to do without having to make up an adapter.
Thanks,
Max