Compressor Saftey

[nmx6000]

Hi Im hoping to use a mini compressor in my feather combined with a pressure switch to run the flipper at 10bar, I realise that i would need an 11 bar release valve but my saftey concearn is over adapting the compressor to connect to the phnumatic system in the bot.
It seems that the least modification would be to aquire one of the commonly avalible male hose tail bspt fittingings to use on the bot phnumatics, remove the tyre valve adaptor from the end of the compressor hose push it on to the hose tail, secure with somthing ( such as a jubillee clip ) and away I go. But will it pass the tech checks for saftey?

[big_nipper]

Compressor Saftey

If not Im in trouble. We took the hose off completely and a standard 6mm 10bar pipe fit over it. All we then did is fit a home made clamp (tried a jubille clip but didnt have one the right size).

The problem we had was when the compressor ran hot the pipe burst so we turned it down to 8 bar.

I dont see any probs with it and are planning to take it to preston where Ill find out if anything needs changing.

[Mouldy]

Compressor Saftey

I myself left the Pipe and valve on the compressor and a had a special pneumatic push fit on the end and used the lever from the valve as my Dump valve. This worked extremely well and I never once had a problem in Turbine 3.

An alternative method would be to get some 6mm id nylon tube and get it crimped onto the output of the compressor; this is what Tkm2 do with success; however the tool to do the job is rather pricey just for doing a one off job.

Ill bring some of the brass push fits along to FWS if you are going ask me and ill give you 1. Also I would recommend you get a pressure switch from technobots so when your compressor reaches the maximum pressure of 10bar it will fire a relay to switch of the compressor. Best of luck.

Regards
Dave moulds
Team Turbine/PLF

[maddox]

Compressor Saftey

About safety. If the hose connected to the compressor comes lose,or melts; what is the worst thing that can happen?
In a robot, in the arena.In the worst case you have a constant battery drain, gears turning, and some air flowing.Remove the link, no problem anymore.
The realy badest scenario is simple.Testing at home,and the pressure going to high.A bursting pipe at 300 psi is some shrapnell.Now, if you adhere the safety rules about pneumatics, like fitting a pressure relief valve rated at the right setting.Then even that isnt a problem.

So, the FRA rules protect you even at home.If you follow them.

[jamesb]

Compressor Saftey

here is an interesting question I was given by a new roboteer recently. I think it fits well here.

My friend was running a 250psi system, but had a coke bottle as his main bottle. It was filled with compressed air to 250psi by an external compressor prior to sending it into the arena.

His question was, having read the robot wars rules, this system appears to be illegal. According to the rules, he MUST have one of the co2 bottles listed. This means, for seafety reasons he must put 750psi liquid co2 into his robot, as it is not safe to do it his way.

not actually looked into this yet, but it would be pretty funny if this was the case. Anyone know different?

[jim]

Compressor Saftey

Im not sure if I follow you, James. Having a CO2 bottle doesnt mean you have to fill it with CO2.

[jamesb]

Compressor Saftey

no no, I mean this roboteer was bemused by the fact that only 3 or so bottles were legal.
He laughed that he had to put in a 2 kg ali bottle, in place of a coke bottle, and as its in there it might as well be 750psi once you amke the investment.

as I say, its silly, but there are roboteers out there event now with steel bottles for sub300psi systems.

[kaideejee]

Compressor Saftey

How much pressure can you safely get into a plastic coke bottle? And how do you go about attaching pneumatic fittings? I considered all this a while back but couldnt figure out the technical side of it all. Not considering it any more, but just curious.

-- Kev

[jamesb]

Compressor Saftey

the coke bottle, and as far as Im aware, the pepsi bottle, are rated at 300psi. do not ask me how, or why I know this, I just do. Something to do with model sircraft but Ive no idea how the subject came about.

attaching fitting is easy, drill 2 holes in the lid, and screw in pnematic fixings. Use resin to add extra security if you want.

this is a very reliable and lightweight solution, which rex garrod used in his 12kg rexs robot challenge. (although at 50psi)

the best thing about this is, you make the lid with the fittings, and you can attach about 15 different size and style bottles to it, giving you lots of options.

1 problem, you have to drink the coke first, which apparently is bad for you?

[jim]

Compressor Saftey

I was reading something about these bottles earlier, I think they said they would burst at 14 bar (~210 psi ish). Either way are Roaming Robots likely to allow a coke bottle as a pneumatic part?

[fwsorg]

Compressor Saftey

FRA rule 8.3.:
The compressed gas shall be stored in a comercially manufactured gas cylinder of appropriate design, specification, and certification. Except where the maximum storage pressure is less than 50psi (3.4Bar).

This raises another question- in the origional Cassius, Rex used an F1 role bar as the basis of the chassis, but also stored 100psi CO2 in there for the suspension. It had no problems containing that pressure (it was thick, high grade steel), and Im sure the whole system would have been implimented safely. Would it still be outlawes under these rules, or is there room for negotiation on this issue- i.e to ask the EO prior to the comp?

[jamesb]

Compressor Saftey

hum... we need to test these coke bottles as I have always worked to 300psi.

[kaideejee]

Compressor Saftey

So with a couple of reasonable sized bottles I imagine you could get a comparable number of same-powered flips as someone on CO2. Or I spose you could use a 500ml bottle as a 10bar buffer tank - that would save some weight.

Id be tempted by FP tho as regulators are expensive

-- Kev

[blazerbotics]

Compressor Saftey

so are two burkets! id prefer to pay 15 quid for a reg, instead of 140quid for a pair of valves!

[fwsorg]

Compressor Saftey

Coke bottles would be excellent, cheap, high capacity, large orifice buffers. Still the concept of using soft drinks bottles to stored high pressure CO2 is quite a worrying one on the face of it. Some official input would be much appreciated :-)