Pneumatic Relief Valves

I have been to my local supplier he told me that they no longer sell the ones i have they have to be fitted with a pipe to stop them freezing up he can get them made for me 2 to 3 weeks around £70 each but might be abble to get them cheaper if i need more than one

are 1000psi burst discs available, if so would these be acceptable? I assume theyre cheaper, and i know they arent as pratical as valves, but seeing as the valves are hard to get hold of and i understand what paul is saying about buying a batch.

but it may be another alternative.

any chance you could get the data sheet Lee ? Might be worth running them past the FRA first, just in case.

Alan
Might be worth asking about that one

I can ask him he just told me these are the ones they have to use now
i like the burst disk idea

I was wondering about 1000psi burst discs the other day. Theoretically it should be ok, but you do risk loosing all your gas on a hot day whereas with a relief valve it just dumps enough gas for the pressure to drop to below 1000psi.

Somthing like a 1200psi burst disc would probably be more useable but that would mean a change in the gas pressure rules which I imagine is very unlikley to happen.

Alan: I assume your burst disc idea is to have one inline with the pneumatic system like the relief valve and not replacing the one on the bottle ?


Dominic

http://www.ukrobotics.comhttp://www.ukrobotics.com

yeah, just takes the place of the PRD and leave the disc on the bottle, as you dont want it blowing when you leave your co2 tank in the car!

I think its 17 degrees rise in temp causes a 1 psi rise in pressure (Boyles law)

http://www.flowstar.co.uk/http://www.flowstar.co.uk/

Flowstar Ni Relief Valve Type 5.3 & 5.2
Totally enclosed right angle safety valve. Type 5.3 with brass body / soft seat. Type 5.2 with stainless steel body/soft seat. SIZE RANGES: ¼€ BSP inlet x 3/8€ BSP outlet 3/8€ BSP inlet x 3/8€ BSP outlet ¼€ NPT inlet x 3/8 BSP outlet (5.2 only) SET PRESSURE RANGES: Type 5.3 0.5 to 120 BAR (G) Type 5.2 0.4 to 200 BAR (G). SEAT MATERIAL: Standard Viton (options from EPDM Kalrez) (In future as overflow valve ACC to Ce-certification, directive 97/23/EC ped).



http://www.dabengineering.com/burst_disc_assy.htmhttp://www.dabengineering.com/burst_disc_assy.htm

The above seems like a small company and may well be willing / able to supply a lower rating burst disc.

Thanks Woody, e-mails sent :)

I have just poss found a supplier for the valves i any one wants one please put your name here or mail me direct so i have an idea how many i need and try for a better discount

we need at least two depending on price.

I need one.

I need one. Just had a price returned to me. £150.00. YIKES

get 2 at that price si

ye, one for each foot !!!!

PS It seems to be aceptable to use 1000psi burst discs. Will let you know if I get any prices.

Looks like I am upsetting more people by not supplying the 1000psi valves then I am by supplying them.

Valves are once again available to order from Technobots, there has been a small manufacturing price increase from last year. Stocks due in early April.

Paul
http://technobots.co.uk/en-gb/dept_121.htmlhttp://technobots.co.uk/en-gb/dept_121.html

paul, would 1000psi burst discs be acceptable?

I would say Yes, (but Im not Paul).
Unfortunatly I never encountered a 1000psi burst disk.

But for safetypurposes in our machines it is an alternative to the relief valves, and weights less, takes less space. 1 Disagdvantage. 1 sleightly fuller bottle, or a warmer day, and youre venting the CO2 without any recourse.With the current relief valves it vents until the preset pressure is reached.

Also, DO NOT TAMPER WITH THE STORAGEBOTTLE.Leave the burstvalve where it belongs. In case of a 1000 psi burstvalve, that one has to be in line with the rest of the pneumatics in the robot.

Nice one Paul !!!
Will order on 15th when I get paid.
Cheers

Alan, I gave this response to Simon the other day:

A burst disc is a pressure relief device and as long as it is certified to rupture at 1000 psi then it would be acceptable from a safety perspective. I would not recommend it for the 1000psi limit as this pressure can be and has been achieved in outdoor summer events due to ambient temperature and direct sunlight. Once the disc ruptures, thats it, it does not re-seal afterwards.

Hope that helps

Paul
FRA Technical Team

Alan,

Mutes relief valve was popping frequently at Eds event in the middle of summer.

Best stick to the refief valve as it will reset when the pressure/temperature drops off. I would have hated to see 4.4Kg of CO2 spew out from a ruptured burst disk... mind you it would have cooled things down a little cos it was a scorcher :)

i know once it blows then all your gas has gone, i was just looking at alternatives. Eds event (and rogers) were the only times i have known for the valves popping, but precautions could be taken to keep the bottles cool etc.

Again it all comes down to money, within the next few months we would need 3, thats £150, i could buy a new pair of hawkers instead, and as you know, we need all the batteries we can get at the mo! :o

ill try that again :proud:

Alan, you have too many robots! I cant even manage to keep one on the road.

Paul

i keep thinking that, all i can say is, thank god the ant doesnt need one aswell!

Who said all of ours were on the road! It would be nice if just one worked without having problems! sorry i started dream, thank god for student loans!

I got some prices on burst discs. If you want the detail send me an e and I will forward. But Pauls relief valves still work out the cheapest option.