1000psi PRV

[beast]

Re: 1000psi PRV

N2O the way to go then

i think not

[widow_twanky]

Re: 1000psi PRV

Dave stand corrected...

I thought that if you can't ever get 1000psi in the system then what's the point.
Just looked at a burst disc, didn't realise they were at 3000psi!!

Take it back, just something I've been thinking about over the last few months.

John

The 3000psi burst disc is to protect the tank. In theory (if you haven't thrown it around, refilled it countless times, subjected it to impacts with an xe or thrown it six foot in the air numerous time) the disc will go well before the tank blows up. We tried this recently on one of our sites with a bottle of propane and a welder which was interesting, trying to explain to people that things worked as they sould when you discharge a full bottle of propane through the burst disc and it's on fire is challenging as well .

As for the 1000psi prv I had heard it was very much introduced as a fair play device (I think it was Geoff told me that). Seem to recall it was to stop people artificially heating the bottles and gaining an advantage due to the increase in pressure. Lots of ranting about people running bottles under hot water taps who should know better followed but the first bit sounded sensible

[Gasbot]

Re: 1000psi PRV

Back in the day we did have the PRV blow off. Was a nice warm day and 4Kg of CO2 on board - PRV opened as soon when I opened each bottle - queue a huge cloud of CO2 and a rather nervous me. Can't really see the point myself though as our system is more than capable of 1000psi not to mention once the gas starts flowing the bottles won't stay at high pressure for long anyway. I think the PRV's were introduced to keep the hydraulics people happy - I do remember being accused of cheating in a competition once as someone thought we had over filled our tiny 1.1 Kg bottle...

Personally I'd say the PRV is more of a mechanical force limiter to protect our chassis from bending rather than prevent the gas system exploding.

[blazerbotics]

Re: 1000psi PRV

I have had mine blow twice when the bottles were warm. I think we have to have a PRD, if not there are no safety devices at all in the system. As John said, Burkerts are only rated for 50bar (although i do seem to remember Mike Lambert getting some tested to 90bar) so we are running them over what they were designed for some times.

[team_mute]

Re: 1000psi PRV

Does everyone have them tested, only ask because we use casting for some of our kit and each one is tested, we had identical castings cast as the same time and same pattern and one past @ 90bar and the other only reached 70bar before it failed, not all casting are equal.

Mute doesn't use burkerts so I haven't got a clue about them, we use cryogenic valves rated for 100bar operating pressure with our billets valves

[jonny]

Re: 1000psi PRV

Burkerts were re tested gland found to be fine for 1000 psi, the only problem is they can't switch it at there nominal voltage so you have to over volt them or run a 12v coil

[Gasbot]

Re: 1000psi PRV

Yes but there is a difference between testing one burket out of thousands and testing the burket that you just purchased. If the max rated pressure of a component in the system is less than the opening pressure of the safety device then what is the point of having a safety device?

Surely it stands to reason that if the item you are using hasn't been designed or tested to 1000 psi then it isn't rated to 1000 psi? Either way its your hand that you are switching the gas on with and not mine.

Hydro test them, water pressure testing is safe(ish) - gas testing isn't.

[maddox10]

Re: 1000psi PRV

The burkert 5404 bodies are pressure cast. The chance there is a defective valve is rather small. And even so, the wall thickness of the brass is more than enough to withstand a lot more pressure.

The part that will fail if hugely overpressured is the seal between stainless solenoid core and the body.

Oh well, how many Burkert-body pressure failures did we see in the 14 years of use in European Robot Wars?

Or bottle-burst disk going?

[Gasbot]

Re: 1000psi PRV

Well Burket rate them for 50 Bar for some reason - maybe they don't know what they're doing

What about rule 9.7 of the build regs - All pneumatic components used with pressures greater than 50psi (3.4bar) must be rated/ tested to at least the maximum pressure available in that part of the system.

And 9.8.1 - Rating Pressure relief devices must have a rating of 1000psi (68bar) or 110% of the pneumatic component with the lowest maximum working pressure rating protected by that particular pressure relief device, whichever is the lower.

14 years use, maybe its down to luck? Like I said, its your hand not mine.

[Mouldy]

Re: 1000psi PRV

A lot of comments about but my robot can take over 1000psi....sure it can... but the robot next to you in the pits might not be able to take it... we have to work to a common rule set at the end of the day.

Burket HAVE to advertise the rated pressure as less then it will actually go upto by law.

I had turbulence blow a PRD once at an event on a 2kg bottle... and ive seen about 5 PRD's on the 600g bottles and paintball bottles go

[widow_twanky]

Re: 1000psi PRV

The part that will fail if hugely overpressured is the seal between stainless solenoid core and the body.

.......and that's probably where the problem is. If the seal goes then what happens? It being connected to the flipper/axe/whatever else there is.

[blazerbotics]

Re: 1000psi PRV

I'm certain Mike Lamber had the Burkerts pressure tested to 90bar to keep Mentorn happy, it probably wont work at that pressure, but as long as it doesn't blow. Best ask him about it.

[jonny]

Re: 1000psi PRV

People have been using buckets in their fp systems for years, anyone had one blow?

[Mouldy]

Re: 1000psi PRV

yup- people have had swarf get into them etc...

Also... why are you getting so hung up on burkets? ... again.. not everyone uses them.

[maddox10]

Re: 1000psi PRV

The part that will fail if hugely overpressured is the seal between stainless solenoid core and the body.

.......and that's probably where the problem is. If the seal goes then what happens? It being connected to the flipper/axe/whatever else there is.

If the robot it build according the rules, nothing will happen, as the weapon has to be locked in the position.

And with hugely overpressured , we're talking 2000 psi or more. I'm willing to pressuretest all Burkert 5404's in use in RW up to 1500psi.

Those won't fire in most cases, but won't leak.

Well Burket rate them for 50 Bar for some reason - maybe they don't know what they're doing

Because 50 bar is the pressure Burkert can garanty the soleno¯d will do the job at the rated voltage of the coil. Nothing to do with the pressure capacity of the body.
Also, the dimensions of the body are standarized. There are several brands of valves you perfectly can interchange in size and mounting. But for now Only Burkert and the lesser know Slovakian Alpha valve are know to be afforable and useable for our applications.

And why the sudden campagn against Burkerts?