1000psi PRV

[terry]

Re: 1000psi PRV

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.

[beast]

Re: 1000psi PRV

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 )

[Mouldy]

Re: 1000psi PRV

no john...For the reasons above.

[widow_twanky]

Re: 1000psi PRV

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.

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.

[jonny]

Re: 1000psi PRV

if andy can't find one, i have one you can have.

[beast]

Re: 1000psi PRV

they are all different sizes and different fittings

ill pop to barbrough bros in brum

[Gasbot]

Re: 1000psi PRV

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.

[PJ-27]

Re: 1000psi PRV

I thought it was a requirement that all components were rated high enough? Or that your PRV was rated below your weakest component?

[beast]

Re: 1000psi PRV

My only problem is 50 Bar components operating at upto 69 bar

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 bar

[maddox10]

Re: 1000psi PRV

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.

[harry hills]

Re: 1000psi PRV

In any case, we're building Combat Machines. Not bumpercars or animated barbiedolls.

QFT

[Gasbot]

Re: 1000psi PRV

I think I'm banging my head against a wall here. Fail safes, removable links, power lights - pressure components that are suitable... anyone catch my drift?

Maddox10,

We are not building combat robots or bumper cars! We are building pressurized vessels & systems which are all designed to a maximum working pressure which is specified by a manufacturer. In 'your opinion' a 50 bar device is suitable for 69 bar (even if that pressure cannot be reached). The manufacturers maximum working pressure is 50 Bar, hence without any further information from the manufacturer (these are not home built devices we are talking about) we should surely assume that the maximum safe working pressure is also 50 Bar? (and we're not taking burst pressure here)

I do not have opinions when it comes to pressure components, I have a fact that there is a design pressure of X, a design temperature of Y and a test pressure of Z.

I designed my gas systems to 90 BarG, hence I can say that everything in my system excluding the CO2 bottles and pressure relief valve is designed to operate or have a safe working pressure of 90 BarG (the hoses, control valves and couplings are rated higher). I know for a fact that the components I manufactured have a safety factor of 4 due to the stress values I used when calculating the minimum shell thicknesses. I know for a fact that the hydro pressure test was successful on the system to a pressure of roughly 128 BarG for 1 hour.

Your opinions are only opinions and you are relying on the in built factor of safety used in the valves construction.

I remember when people thought it was acceptable to use 10 or 16 Bar rams at bottle pressure, along with the plastic tubing and push fittings. This is the same but to a lesser extent - even if 69 Barg cannot be reached.

Regardless of the above, the build rules say 50 BarG components (because 50 Bar is what the manufacturers rate them at) must be protected by a pressure relief device rated to 110% of the working pressure, or independently tested to 120% of the maximum system pressure, which with a 69 Bar relief valve fitted would be around 83 Bar - which I personally consider to be too low.

The gas system I put into Mute complies with the build rules - do you yours? Or is it just in your opinion that they do?

Perhaps the rules do need changing so that I can skim 2 or 3mm off the CO2 bottles (in 'my opinion' they're over rated anyway) and thin the other components down too I can throw more armour on then!

[maddox10]

Re: 1000psi PRV

If my former job qualification didn't allow me to test and rate pressure parts, I guess we'll have to close down about any European PWR nucleair reactor too, not to count all waste incinerator plants in Belgium, and quite a few in the Netherlands.

As I wrote, and you can get the information from Burkert too. The 50 bar WORKING pressure of the 5404 1/2BSP or NPT valve is dictated by the reliable working of the soleno¯d pilot. Not the pressure rating of the body.



People using any derivate or copy of the Gravity set-up, Gasbot says your stuff ain't safe and not allowed in the rules. I bow to his greatness, and ask humbly that you won't participate in events anymore and scrap your utterly unsafe machines or rebuild those with materials he deems safe.

[maddox10]

Re: 1000psi PRV

I think I'm banging my head against a wall here. Fail safes, removable links, power lights - pressure components that are suitable... anyone catch my drift?

No, I'm probably to stupid.

Maddox10,

We are not building combat robots or bumper cars! We are building pressurized vessels & systems which are all designed to a maximum working pressure which is specified by a manufacturer.

Probably there ain't a difference between working pressure and pressure rating.

In 'your opinion' a 50 bar device is suitable for 69 bar (even if that pressure cannot be reached). The manufacturers maximum working pressure is 50 Bar, hence without any further information from the manufacturer (these are not home built devices we are talking about) we should surely assume that the maximum safe working pressure is also 50 Bar? (and we're not taking burst pressure here)

My opinion is backed up by pressure tests done to get UK machine to participate in Battlebots.

I do not have opinions when it comes to pressure components, I have a fact that there is a design pressure of X, a design temperature of Y and a test pressure of Z.Your opinions are only opinions and you are relying on the in built factor of safety used in the valves construction.

Sorry that English ain't my motherlaguage (nor father). I should have used another word. Maybe that this semantism satisfies your thirst for accuracy.

To my knowledge a Burkert is overdesigned concerning pressure rating, for the job it does.

I designed my gas systems to 90 BarG, hence I can say that everything in my system excluding the CO2 bottles and pressure relief valve is designed to operate or have a safe working pressure of 90 BarG (the hoses, control valves and couplings are rated higher). I know for a fact that the components I manufactured have a safety factor of 4 due to the stress values I used when calculating the minimum shell thicknesses. I know for a fact that the hydro pressure test was successful on the system to a pressure of roughly 128 BarG for 1 hour.

Tough as Nails has had active pressure tests at 130 bar with nitrogen.

I remember when people thought it was acceptable to use 10 or 16 Bar rams at bottle pressure, along with the plastic tubing and push fittings. This is the same but to a lesser extent - even if 69 Barg cannot be reached.

Those we still have. I just hope we can inform those people before they hurt themselfs.

Regardless of the above, the build rules say 50 BarG components (because 50 Bar is what the manufacturers rate them at) must be protected by a pressure relief device rated to 110% of the working pressure, or independently tested to 120% of the maximum system pressure, which with a 69 Bar relief valve fitted would be around 83 Bar - which I personally consider to be too low.

The gas system I put into Mute complies with the build rules - do you yours? Or is it just in your opinion that they do?

Yes they do. After consulting with event organisers and some other knowledgable people. yes.

9.7 Rating
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. You may be required to provide documentation/
certification to support this.

I can produce the pressure test results of the systems I did build. All can stand hydrostatic pressure testing @1500 psi.

Perhaps the rules do need changing so that I can skim 2 or 3mm off the CO2 bottles (in 'my opinion' they're over rated anyway) and thin the other components down too I can throw more armour on then!

1.5mm from a 6mm wall. It will still stand the normal pressure. But the 3000psi burst disk could be stronger than the wall then.
Oh well, if you want to gain those few 100 grams that way. Sorry, but I would buy a smaller battery, or one with a better chemistry, like LiFePo4.

9.3 Cylinders
The compressed gas shall be stored in a commercially manufactured gas cylinder of appropriate design,
specification and certification. Except where the maximum storage pressure is less than 50psi (3.4bar).
Some events may have further restrictions on bottle sizes/ weights used, please contact the event organiser
for clarification.

[Gasbot]

Re: 1000psi PRV

With regards to your job you must have provided paper work or certification to your clients to prove that the work was safe and components suitable for the task? And we too have done work for nuclear, power plants, petrochemical, refineries, oil rigs, aerospace, etc all over the world - we've even got kit in space We always provide paperwork and certification which sometimes is worth more than the actual equipment we are selling.

I seriously doubt that burket will give you any certification for any pressure above the 50 bar quoted as it won't be in their interest. If you can get the proof then great, if not then 50 bar is surely the maximum working pressure? This is what I've been banging on about - if it ain't rated, then get them tested. Its simple, quick and easy. Or de-rate, its not as if its a lot of pressure that would be lost. It wouldn't even effect the performance.

Oh by the way, I was joking about skimming the bottles... I ain't that daft or desperate. And commercially available isn't exactly and issue, whether its affordable or not for anyone to buy is a different story.

May be the FRA needs to comment on this matter as I see it as a safety issue with repercussions for insurance?