Who do you get to pressure test your rams?
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Who do you get to pressure test your rams?
They dont have to be pressure tested. And even if they did they are far superior to anything you can get off the shelf.
9.7.1 Custom ComponentsQuote:
Originally Posted by xtreme
Custom made components, or parts operating above the suppliers maximum working pressure, must be
independently tested and certified at 120% of the maximum system pressure available at that point.
Nobody pressure tests there rams.
Oh dear, how do you know they are safe if they aren't tested, we do material thickness calcs on our kit and still hydro them just to make sure.
Only thing you don't have to do as long as your not selling any type of pressure vessel is get it certified for P.E.D.
And if you are selling them P.E.D isnt a problem until you get into the certified body approval, for a CAT 3 job on our equipment we have to pay around £1200.00 for the certification, bit less for CAT 2, Cat 1 and sound engineering we can do ourselves in house
Flows ram isnt strictly a pressure vessel.. since its got a hole in the bottom to atmosphere, and a few holes in the top, the ram itself doesnt contain pressure.... unlike a normal commercial cylinder.
If you were to start making buffer tanks and selling them, then you should supply certification with each item sold to prove its been tested, true.
The ram must hold pressure at some point else it would just vent to atmos even with a leak (I used pressure vessel as a generic term, we sell silencers that go to atmos and we still have pressure test, do calcs etc and PED stuff) the holes at the top I'm guessing are to vent the air from the top side of the ram.
Anything that holds pressure should be tested. In this case I would assume you are saying that the maximum working pressure is atmos due to the hole, even though it will retain gas at up to 40-55 bar?
Rams and buffer tanks would all full under P.E.D if you were selling them, all depends on pressure and size as to which CAT number it falls into.
I do, and I have independents arranging paperwork if needs be. I can't afford any legal shit raining down on me because I made a mistake. I prefer a ram blowing in my workshop, than in the shed of an prototype tester.Quote:
Originally Posted by xtreme
@Mouldy,
any ram is a pressure vessel. Otherwise it can't work.
The Cutlet System (standard feather setup) uses an exit hole.
Now, to put it in perspective. The loathed Burkert 5404 has a let trough of 1/2 BSP =126mm²
An avarage exit hole is 1.5-2mm diameter. Lets take 2mm as example.
0.1*0.1*pi=0.0314mm²
0.0314mm²*55bar= 1.73 kg loss.
Meaning with warm gas entering the ram, you have a max of 54 bar. Dropping fast due abatic temperature differentation.
That's assuming the robot was running full pressure. And to be honest we don't need a full pressure system to have a more powerful flipper than anyone else. Not being cocky but it's just fact.
So who's pressure testing these drinks containers being used as buffers and modified rams that show up? I bet 90% of the pneumatic robots out there have modified or custom pneumatic parts that havent been tested.If you want to get somebody to pressure test my ram feel free. But I can almost guarantee the ram in flow now is far superior to any other rams around that are custom made , modified or off the shelf, iv had a few rams that have been made by other people and none of them are no where near the wall thickness or strength of flows. Machined from a billet with no fixings in the 10mm thick top end cap to weaken it, you tell me what can go wrong. I'd be happy for you to test that ram at 200% or 300% of the pressure I'm running.
Our buffer tanks and anything before the valves will be pressure tested, thats mainly so I know I don't have leaks where the systems welded up etc.
If your testing the stuff before the ram why cant you test the ram at the same time, as you've already said it will be fine so you've got nothing to worry about.
You just need the paperwork to back up your claims
I'm not attacking your way of building, nor your knowledgability.Quote:
Originally Posted by xtreme
But it doesn't matter if your pneumatics are 1000% overrated by your calculations, superiour way of making and testing those.
If you can't show the independent paperwork, if any ruleshark wants to [removed] you over, you have a participation problem
Luckely, the EO's have a lot of braincells rubbing together. [removed] ain't a problem.
I myself am opposed to any rules outside common sense, but alas, if I want to play in the current playfield, I have to adhere to the rules.
And part of those rules are really restricting concerning pneumatics.
Getting independents to certify your stuff is or expensive, or there is a certain degree of non independence.
Oh well. Enough ranting and rulecornholioing. Get those machines ready, and we'll met in the arena.
Rude.Quote:
Originally Posted by maddox10
Mario -
fact 1.... ive had 2 of your rams in the past...niether of which came with paperwork.
Fact 2... ive tech checked pretty much every robot out there... and no one has presented me with paperwork signed by you to say there equipment is pressure tested.
Tom- screw haters... flow's lookin sweet.... but still not quite a duckbill.
True it will never be quite a duckbill
Dave, I don't recall you having any direct deals with me concerning prototype rams. (it also seems you're using any pretext to question my competences or ridicule me)
Was there anything wrong with those rams, except that those are conventionaly machined?
And combine these remarks.
Quote:
Originally Posted by maddox
For the rest.Quote:
Originally Posted by maddox
It's Robot Wars, not rulemongering.
If we would go to the letter , dot and yota of the current rules, events will get very dull.
Tom, sorry that it seems people are interpreting me wrong, but I have 2 excuses.
1) English ain't my native language.
2) I'm blunt, even in daily life.
I would like to see your machine the have a go at it in the arena.
If not, there still is the possibility of backyard rumbles...
Below are the rules for the construction of pneumatic parts/ weapons from the FRA.
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.
9.7.1 Custom Components
Custom made components, or parts operating above the suppliers maximum working pressure, must be
Independently tested and certified at 120% of the maximum system pressure available at that point.
I think the way it is written is un-ambiguous all pneumatic components,
Similar with custom components.
In my field as a gas engineer, if there is an incident I have to prove I am innocent to the authorities.
So let€™s say a custom made component failed and someone was injured, and later it was found the equipment did not fulfil the FRA build criteria would there insurance cover you?
To prove innocense in a robot case , you just need to complete the papertrail as stated in the FRA build rules.Quote:
Originally Posted by craig_colliass
If the rules are followed, the FRA lawyers will be the friends of the Tech checker and EO.
When you sign a Tech Check sheet you are declaring that your robot is built to the rules, therefore you are responsible if your un-certified ram goes pop. I don't recall if anybody has recently being asked for a pressure test certificate etc, but if i saw a ram/bottle that i wasn't happy with i would ask.
I totally agree with that Alan if it looks like a pneumatic system is even the slightest bit unsafe it should be questioned.
Even tested its hard to say if a ram will be safe, after repeated fires of the ram it could start to fracture and become unsafe, Also I could build a ram that would take the pressure and be fine fired by a small 3/2 valve, but I could make it so that same ram would destroy itself being fed by a flow valve. Its not all about pressure with rams really, Its how you feed them. I bet theres a few rams out there that are fine being fed by a burkert, But put a flow valve in place of the burkert and it could quite possibly destroy the ram.
Alan's right on the Technical Check Sheet it dose say.
Pneumatic System
(Where fitted)
Must meet requirements of the build rules including pressure
relief devices and an easily accessible dump valve that are
away from weapons, drive or sharp edges.
Pneumatic System (Where fitted) Must meet requirements of the build rules!
So it's up to the Roboteer to make sure all paperwork including certificates are up to date!!!
I think most manufacturers can supply certificates of conformity for their unaltered parts if this is any help.
I don't know about independent pressure test certificates but there must be companies that do it.
My problem with this, is it is a little impractical, as this is a combat situation as soon as the robot has been in one fight the certificate could be argued to be worthless.
I don't know how to get round this point. You either run the paper trail to no practical advantage or change the rules. :uhoh:
Looks aren't really a good indicator from a mechanical strength view. After all you could get a huge gouge in the pressure boundary, and skim it off in a lathe - looks good as new if you get my point?
Hydro pressure test are the key, but they won't prevent the rams popping due to high velocity ram rods and the like. We had high velocity problems with our setup so its nothing new, we had tie rods stretching, ram mounting bolts stretching, even the cassis was warping, etc, all through extended use - fatigue did start to creep in as time went on. We designed this out (to a point) by upgrading the design as elements fatigued and replacing components as necessary (we never had a failure though!). But assuming that the pins/tie rods dont fail completely a lot of the energy should be absorbed by this failure and gas should be able to escape relatively easily, although I guess this depends on how the ram is screwed together. But assuming that the ram rod wouldn't escape the ram, I would hazard a guess that this type of failure would be less dangerous than the pressure boundry bursting? Either way both are still pretty dangerous.
I think if someone has the knowledge and technical ability to produce pneumatic components then it should not be too much of a stretch to get them tested.
Screw the haters if you like, or stuff the rules! But if a pneumatic component fails, someone gets hurt and the HSE & insurers get envolved we are all going to have very expensive and heavy paper weights sitting at home.
As everyone has said fatigue plays the biggest part here. Regretfully once a robot has been in combat the fatigue has started. There are 2 options to try and cover this situation. Add a rule that ALL pneumatic robots have to be tested and signed off every year (This is practically what we do with spinners during tech check in the arena) or ban ALL systems being pressured whilst not in the arena barring CO2 bottles. Once the robot is in the arena you could then attach your bottle.
The only risk to people is when the robot is around people. Once its in the arena it doesn't matter to us if the ram blows or the rod shoots out. The arena is designed to contain it. If you would be worried about your pneumatic system failing inside the arena then the rules or the arena in question need to be assessed.
If something needs changing I would suggest it be allowing pressure into your robot whilst in the pits area.
Really nice build there Tom! very impressive.
I think it's not allowed to pressurize the machines in the Pits. Not even for testing/leak-finding.
Pressurizing is part of the link-up procedure, just to make sure if anything goes wrong, it happens in the arena. It's also the reason links, dumps and activation valves should be out of the angle of the weapon.
I find it a very interesting discussion, but maybe it's a good idea to make a new topic of it. And not do it here.
It would probably be better to just drop the subject, it's never going to go anywhere. Nobody is going to events with tested and certified rams in their robots and they never have. What's the point going any further with the discussion really?
Seems a little wrong, Mutes stuff was tested when we used to run our custom stuff and will be again before we go to our 1st event, we've had to fork out for CO2 bottles due to being out of test but by your thinking our old bottles looked just fine so we could have stuck with them.Quote:
Nobody is going to events with tested and certified rams in their robots and they never have
I dont understand why your so against testing your ram, tap the vent hole, nice connection for a hydro test line
If you actually go back and read my earlier post on the last page I said if sombody wants to test it they can, I even said id be happy for it to be tested to 200% or 300% of its working pressure, Its just I personally dont see the point in having the ram tested when the flow rate, Weight of the piston rod slamming against the ram top and fatigue isnt taken into consideration. Also for pressure testing even with the vent hole in the bottom blocked its just going to blow past the piston rod and out of the top vent holes in the ram.Quote:
Seems a little wrong, Mutes stuff was tested when we used to run our custom stuff and will be again before we go to our 1st event, we've had to fork out for CO2 bottles due to being out of test but by your thinking our old bottles looked just fine so we could have stuck with them.
I dont understand why your so against testing your ram, tap the vent hole, nice connection for a hydro test line
And also I said I agree that buffertanks etc that are storing pressure should be tested and I also said mine will be tested.
I dont want people going out there with unsafe systems, All it would take is one incident where a roboteer or sombody in the audience gets hurt and it could end this hobby that we all love.
But realistically if say at the next event you asked everyone with a pneumatic system to produce a test certificate for each part of their pneumatic system or they couldnt fight, you would end up with a very boring event with absolutely no flippers or pneumatic axe robots running at all. I bet the audience would love seeing a few robots drive into eachother and push eachother into the pit. :roll:
We ought to do this at the next UK FW champs. Bring on the spinner domination :mrgreen:Quote:
Originally Posted by xtreme
Sounds like a plan, ill have to get one of my spinners done. Get mouldy on the job failing eveyones pneumatic systems. But knowing our luck a box would just win.Quote:
Originally Posted by k_c_r
some you guys need to take up knitting its a tad safer :lol:
all the important parts will be tested with paper work ,we not going to waste money having parts tested for nothing. we do not intend to sell them so if any body is going to get injured it would be us testing them and me n tom are more than happy that they are safe at the pressures we running. If any thing was to go wrong with the ram it would be in the arena when fired and nobody would be in there, and as James said the arena is built to contain these mishaps.
As for testing who tests these drinks bottle buffers that are micro mm walled (as tom mentioned) and hold pressure and are fed by trev regs that can sometimes pass fp ???. Our rams mostly run low pressure and are no less than 8mm walled far better than most fp rams and never hold pressure
Please if this is to be continued please start a new thread :)
So just because a ram passes gas it shouldn't be tested - that is quite frankly idiotic. And dont give me that rubbish that these are toys etc because they are not - a macho stance is great until it explodes in your face and wounds the guy standing next to you.
It makes me sad to see that in the seven or so years that we have been away, things haven't changed at all. This is on par with the 10 bar rams that were according to some 'fine on FP'.
If you are going this far, why not bolt the system together - plug the ram & vents and get a system test done? I.e. do it properlyQuote:
Originally Posted by davet123
If you built it then it is your responsibility to get it tested - no mine or anyone elses.Quote:
Originally Posted by xtreme
8mm wall is nothing special, it might be fine, it might not - it all depends on the relationship between the inner diameter, materal strength, wall thickness and design pressure. Do you have 8mm on at least one side of the tapped holes in the bottom of the ram cylinder or 8mm with the tapped hole? I'm assuming you have checked that your end plates won't buckle from the pressure too? Might be teaching you how to suck eggs but flat plates are very weak when compared to cylinders.
The rules are as clear now, just as they were when we started building these things an age ago. Custom or modified components should be tested. In our first incarnation we had a 95% custom system including the gas bottle, the only off the shelf items were the pipes - it was all tested. We had the tech checkers at RW in a right state as they'd never seen anything like it.
But lets scrap the rules all together - balls to it. Obviously the rule writers were out to spoil our fun and didn't give a damn about our safety! Argue the toss if you like because clearly I don't know what I'm talking about! :x
I hope this does bring in a swathe of pressure test cert checks - because from what you're saying we'll be one of the few pneumatic bots out there who has one :blush:
A new thread under safety
Pneumatic safety issues,
has been started.
Didnt say they were toys, nobody said scrap the rules, And again I didn't say it shouldn't be tested, I said personally I think its pointless for the reasons iv already stated. And when the ram is fired in a safe environment (the arena) Nothing should be exploding in anyone's face and injuring anyone. I'd be happy to have it tested like I said. Nobody's taking a macho stance iv already said robots should be safe and wouldn't want anyone to get injured. You know what your talking about I know, you have been on the robot wars / combat robot scene longer than I have. The subject should just be dropped, chances are its going to end up going nowhere and be like all other similar subjects that pop up on the forum and end up with constant arguing and go nowhere.