TXR - FLOW

[Mouldy]

Re: TXR - FLOW

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.

[team_mute]

Re: TXR - FLOW

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.

[maddox10]

Re: TXR - FLOW

Nobody pressure tests there rams.

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.

@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.

[xtreme]

Re: TXR - FLOW

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.

[team_mute]

Re: TXR - FLOW

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

[maddox10]

Re: TXR - FLOW

yaddyaddy

I'm not attacking your way of building, nor your knowledgability.

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.

[Mouldy]

Re: TXR - FLOW

yaddyaddy

Rude.

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.

[xtreme]

Re: TXR - FLOW

True it will never be quite a duckbill

[maddox10]

Re: TXR - FLOW

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.

Getting independents to certify your stuff is or expensive, or there is a certain degree of non independence.

Enough ranting and rulecornholioing.

For the rest.
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...

[craig_colliass]

Re: TXR - FLOW

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?

[maddox10]

Re: TXR - FLOW

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.

If the rules are followed, the FRA lawyers will be the friends of the Tech checker and EO.

[blazerbotics]

Re: TXR - FLOW

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.

[xtreme]

Re: TXR - FLOW

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.

[craig_colliass]

Re: TXR - FLOW

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.

[Gasbot]

Re: TXR - FLOW

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.