Pneumatic Relief Valves

[stu]

Pneumatic Relief Valves

Alan, in feather weigths - a burst disc on the bottle is acceptable. Jonno checked with Paul Cooper (FRA Pneuamtics bloke) and the Burst disc on the 600g co2 bottles is fine to act as a High pressure relief valve.

But in all honesty im not sure about a low pressure relive valve. I feel there should be a small one on the low pressure side as well - but i dont know, have to ask Paul on that one.

But yeah - you wont have to spend £50 on a HP relief valve, you already have one so to speak.

Mr Stu

[blazerbotics]

Pneumatic Relief Valves

just to bring this thread back again! but after the confusion at Brighton over the 1000psi PRD on feathers. things need to be made clear for all feather builders.

My understanding of the rules were as above, in stus post. But then at brighton we were told that G3 couldnt run without a 1000psi PRD. There was then some confusion over the burst discs and the set pressures. as the code on the disc is PN250, people were assuming it was set to 250bar but the bottles are only tested to 205bar. we were then told that we were allowed to run g3, my understanding was due to somebody saying that the disc was set to about 1000psi.

I know the subject was raised at the FRA meeting, and it was stated that feathers MUST have a 1000psi PRD. If this is the case, then its going to cause a few arguments. I have already spoken to a couple of builders who are building and one of them has scrapped there plans to build theres due to the added costs. I have put my plans on hold for Delta as i can afford to buy a PRD for it. As i already have to buy one for my middle.

As i said above, i have no problem in fitting a LP PRD but i think a 1000psi PRD is abit over the top for a feather (see my above post for thoughts).

Could we please have a definate answer, and make sure people are aware of it.

[m2xt]

Pneumatic Relief Valves

Alan,

Rule 8.2 states the maximum pressure within the pneumatics system shall not exceed 1000psi. Rule 8.8 further defines the maximum pressure being determined by the PRD.

At the FRA meeting I stated two exceptions to a 1000psi PRD requirement, for sytems having a max pressure below 50 psi and for compressor driven systems with a maximum output pressure lower than the lowest pressure rated component.

I certainly do not agree it is over the top for feathers, if its good for heavies its equally as good for feathers as the consequencies are just as serious. Remember, its function is not only safety but also to ensure a level playing field and avoid the need for test points.

If a builder cannot afford the safety devices then they should reconsider if CO2 powered pneumatics is for them.

If you wish to propose that the 1000psi relief valve is removed as a requirement for feathers, you know the procedure. I am an advisor, it is for the voting FRA members to decide one way or another and rightly so.

Paul
FRA Technical Team

[m2xt]

Pneumatic Relief Valves

On a personal note:

Technobots currently do not sell the 1000psi PRD for 2 reasons, one is to avoid any suggestions of conflicts of interest and two more importantly is because demand has fallen to such a level as not to warrant the manufacture of another batch.

Paul

[blazerbotics]

Pneumatic Relief Valves

where can we get them from?

In regards to:

Remember, its function is not only safety but also to ensure a level playing field and avoid the need for test points.

how can it effect a LP system, and as i said above, i have no problem putting a LP PRD in. also a test point would be alot cheaper to put in then a PRD.

[fwsorg]

Pneumatic Relief Valves

It shouldnt affect LP systems, but it will affect FP for obvious reasons. If someone knows of a supplier of 1000psi PRDs, then please let me know before I begin an assault on the RS website.

[m2xt]

Pneumatic Relief Valves

Alan,

The effects on regulated LP systems are less obvious than HP systems. Higher bottle pressures means higher delta pressure across the regulator and thus improved flowrate. Also as you know, as you use CO2 it chills, start off with a warm / hot bottle and this effect will be delayed. For reference and from memory at 31 Deg C, CO2 behaves in a different way with further temperature rise causing an exponential rise in pressure. This point is I believe at 1000psi. Dont worry, I have used and understand the arguments against the 1000psi relief valve.

As I said propose its removal if you wish.

Paul
FRA Technical Team

[maddox]

Pneumatic Relief Valves

Gloor has some regulators for oxygen that have a 900psi relief valve.
I had a batch of those, and can probably reorder, but not for 2 ofm.
The last time I was rather unplesantly surprised by the pricetag for less than a 100 seperate ones. And normaly they come as a part of a repair/overhaul kit, that is about as expensive as a new regulator.
If enough people contact me, I can try again for a useable deal.

And, when using CO2 or any other storaged gas on pressures higher then 16 bar(max nominal pressure low pressure systems) I insist on a relief valve, set at the maximum allowed pressure of the system or at 1000 psi as maximum in the rules.

Now, according to some I do not know what Im talking about, so ignore the rambling.

[babeth]

Pneumatic Relief Valves

No, but maybe people are being deceived by your poor grammar...
For those who are: you are dealing with a Belgian for whom English is not a native language nor has he had English courses for 8 years in a row like I (fellow Belgian) had. It does not have anything to do with his technical knowledge. He is however speaking not only out of school training, but also some 10 years of practical experience as well.
Mario is of the Technical Committee in the Dutch roboteers association DRG too. Like Paul Cooper he gives advice, he does not state laws. And is open for suggestions.

Im just trying to make things clear to everyone, not simply defending my lifemate. Right ?

[woody]

Pneumatic Relief Valves

CO2 behaves in a different way with further temperature rise causing an exponential rise in pressure. This point is I believe at 1000psi.

CO2 Dynamics Graph...... In support of Pauls statement.

http://www.warpig.com/paintball/technical/gasses/co2pv.gifhttp://www.warpig.com/paintball/tech...sses/co2pv.gif

[jamesb]

Pneumatic Relief Valves

sorry, did I miss something?
who said Mario doesnt know what hes talking about?

[m2xt]

Pneumatic Relief Valves

Thank you Alan, you provided that link some time ago but couldnt find it this time.

James, certainly not me!!

[Guest]

Pneumatic Relief Valves

I think for those ppl that know Mario, Do know he knows what he is talking about

[leorcc]

Pneumatic Relief Valves

does he?

Maybe thats why my robot was on his coffee table in the living room.

[audrey_aka_leah]

Pneumatic Relief Valves

Im glad some people do.. considering I dont read half of the post anyway.. and when i do, I havent the foggiest what you lot are on about *giggles*

oh.. the joy of ignorance *giggles*