Pneumatic questions, sorry!

[Max]

It would be very difficult for me to put the dump valve between the buffer and the QEV but if that is my only option I will probably have to make a custom component to make it fit together in the space I've got.
I don't know why yours doesn't fire, as I see it, it is the same as switching the 5/2 valve to dump the gas in the pipe going to the QEV causing it to fire.
perhaps an option would be to severely restrict the gas flow out of the dump valve to the pressure doesn't drop fast enough to fire it, but then it would take forever to empty. I am sure Mario said to me at Maidstone I could use a small spring to stop it misfiring but I am struggling to find one suitable. The best I have come up with is using a paper clip wrapped round a large pencil to make it into a spring shape but I doubt that will work for long!

[Liftoff]

Can't you fit a Tee fitting directly to the buffer? Then you could connect the QEV to one side and the dump valve to the other. Don't know how placing a spring on the QEV will work, the way I see it once you dump the inlet of the QEV, spring loaded or not, the pressure inside the buffer tank will push the sliding seal inside the QEV and fire the ram.

[Eventorizon]

Been watching back over RW and trying to spot all the little hints and tips teams give to maximise the power or efficiency of their set ups.
The one that stood out was using Liquid CO2 like in Chaos 2 and a few other machines but so far as I know we cant get liquid CO2 at events. Also it seems logical that you would end up freezing the valves as the gas expanded into the cylinder causing it to jam. But there must be ways round this if Chaos 2 can use it with no problems.

Another which Kane mentioned was to have the largest buffer tank you can, so the gas can easily flow into the cylinder. Also making the routes as direct and straight as possible so you don't waste energy in the process.

Are there any other little tips people can suggest, or correct me on these ones.

I also have this half used powder extinguisher in my flat.
2013-06-03 15.22.00.jpg
Physically it is fine its just never been repressurised. Would this be alright to use as a buffer or even a main tank?

It has the following on the side...
Working Pressure: 13.5 Bar
Test Pressure: 22 Bar

The maximum our cylinders can take is 16 bar so it would be 37.5% less than the testing pressure. And if I remember right, parts must be tested to 20% more than their intended operating pressure so this would be ok.

[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