As per title- Pm me with a price if you have one.
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As per title- Pm me with a price if you have one.
When do you need them?
I need one too, where sells them ?
http://www.esska-tech.co.uk/esska_eng_s ... ifica.html could work if wound right up? quite cheap.. you'd need a G 1/4 tap to make it fit your buffer etc or an adaptor to fit it to BSP i guess. But the price seems good...
G 1/4 is 1/4BSPP
Good site that Dave - added to my Favourites already.
60bar is around 860psi, but a 2kg CO2 bottle with 2kg of gas is only 700ish psi when I put a gauge on one years ago, so should work - FRA rules say that 1000psi prv has to be certificated, maybe we could get Kane to test and calibrate some.
Let's be real they are a waste of time, we should take them out the rules !!
The burst disc In the bottle covers it anyway.
John
I have a fp prv, dave has first refusal though .
Yep, i thought it might be but wasnt sure if the G ment it was the finer thread type you often see in industry for compression type fittings... being BSP makes it even better...
Also yeah i figured 1000psi which most roboteers seem to state isnt really true... i figured it would be around 750psi max as thats when co2 becomes liquid?
If you pay the exstra £2 or whatever it comes with a certificate... which means it should be allowed within the FRA rules IMO.
@John;
Burst discs dont go at 1000spi... the 1000PSI PRV rule was put into place to protect against components rated to 1000psi tops... so if someone turns up to an event with a buffer tank theyve tested at 1000psi... they wont risk letting that component go over pressure.... (Sorry if thats teaching you to suck eggs, i guess you already know that)
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
I think it was also to stop people using other gases.
Yeah roger plant using nitrogen in wheelie big cheese !!
just ordered one, came to £23.39 with shipping etc...
When i get it, ill hook it up directly to a co2 nut , screw it onto the bottle and post results for anyone who's in need of one...will be after telford though as ive got no co2 here :sad: ...thanks in advance for your co2 Alan :P
Jonny- if this one doesnt turn up/work ill be interested
Interesting site. The springs I need for the PRV's are almost as expensive as those 60 bar PRV's.
Also, the PRV doesn't have to be rated at 1000psi, it's the max allowed by the rules.
@John
what you and I are trying to say is whats the point in a 1000 psi valve when
a co2 bottle at proper weight ie 2kg no more is filled properly to 42 BAR whick is 617 psi
ok if its hotter the bottle presure will be higher (we all know that) but when people are useing buffer tanks and we fill the system we are normally filling say another 2kg of empty tank which does 1/2 the presure I have tested this (not on a hot day) and the presure was 350 psi now a 1000 psi valve will never blow off i have had one in the system for over 10 years now and it has never blown off.
as long as the bottle is never over filled you should not have a problem.
and as we always arm the robot in the areana having a safty valve which does not blow off in my opinion is a waste of time as it does not make the robot any safer
Also burket valves are rated to 50 bar which also is less than 1000 psi of which i have uesed for over 10 years as well
so Can i ask whats the point if we are only going to use CO2 ?
Alternatively John you could prove with certification that your entire setup will operate safely on 3000psi :)
Just because you have massive buffer tanks and know not to fill your bottle to the max when it's frozen on a hot day doesn't mean everyone else does...
N2O the way to go then
i think not
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 :rofl: .Quote:
Originally Posted by roamingrobots
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 :proud:
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... :angry:
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.
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.
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
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
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.
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?
Well Burket rate them for 50 Bar for some reason - maybe they don't know what they're doing :lol:
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.
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
.......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.Quote:
Originally Posted by maddox10
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.
People have been using buckets in their fp systems for years, anyone had one blow?
yup- people have had swarf get into them etc...
Also... why are you getting so hung up on burkets? ... again.. not everyone uses them.
Quote:
Originally Posted by widow_twanky
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.
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.Quote:
Originally Posted by gasbot
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?
Blew the burst disk on one of my bottles recently, wasn't in the robot the prv would have gone way before, so need a new burst disk if anyone knows where to get them ? Wouldn't want to run the robot without the prv though.
yeah thats mine terry ( they only blow if over filled and heated tho )
do u still have the screw terry or did i take that back as i lost it lol
but back to 1000psi prv can we change the rules that we dont need one ( as long as fair play is involved and co2 used )
no john...For the reasons above.
I changed over a few lever valves a while ago and set the burst discs aside. Can look at the weekend to see if i can find them.Quote:
Originally Posted by terry
if andy can't find one, i have one you can have.
they are all different sizes and different fittings
ill pop to barbrough bros in brum
No problems with burkets at all, but I doubt the solenoid is the only factor limiting the pressure. My only problem is 50 Bar components operating at upto 69 bar.
Without knowing the design pressure of the assembly, the materal grades used and relative internal diameters & thicknesses - randomly choosing a test pressure could be dangerous. If you exceed the yield limits of the metals used, they will probably pass hydro test but may fail in service at some later date. But I agree that any valves should be tested if used above their intended design pressure - although I wouldn't want to provide the guarentee in case one did fail. Also I wouldn't test the units to a pressure any higher than is necessary.
Not being picky or arsey but safety is safety. I heard a horror story recently from a visting assessor coming in for a witnessed hydro test, he took a look at the assembly and pointed at the drain plugs we were using. He then went on to tell me how a man lost his life during a pressure test all thanks to a 1/4 BSPT plug that stripped its threads. Could you imagine having to live with that all for the sake of a hydro test?
For your own safety, if the components in the system are rated for less than the relief valve then get them tested.
I thought it was a requirement that all components were rated high enough? Or that your PRV was rated below your weakest component?
as is proven any system with lage buffer tank ie 2kg buffer the presure is about 350 to 400 psi divied that by 14.7 and its no where near 69 barQuote:
My only problem is 50 Bar components operating at upto 69 bar
Gasbot.
Untill 2010 I had the official paperwork designating me as a certified pressure technician, allowed to write and authorise test reports.
In my opinion a Burkert is overdesigned for the job it does. Given a stronger solenoid, those valves are fine with working pressures over 1200 psi.
But you don't have to believe me.
In any case, we're building Combat Machines. Not bumpercars or animated barbiedolls.