Hi all, Can you help me with Pneumatics? sorry

Hi all. I hope this forum is as friendly as it seems from the outside :wink: .

Im completly new to robotics but i do like trying to make stuff out of anything that looks like it might, with a little bit of imagination be a perfectly usefull (or fun) something else. I find i have a nack of crafting stuff together and enjoy doing it. With that in mind I have been eager to give myself a project to do for some time to stave of the temptation to stare at the telly box (boring!!). I have decided to try and build a big robot. (A heavy weight I suppose.) I€™m not looking to make anything over night but spend as long as it takes to complete.

I decided on a flipper type design and as such have been doing the research to try and figure out how it all works. With the help of reading through countless posts on this forum and following the suggested links I feel i have come along a great deal in understanding how the system works but as always i am still left looking for answers. Hence this really rather long drawn out post. (sorry!)

I have drawn a little diagram of what i think the Pnuematic system will be like PLEASE help me in the right direction if im going the wrong way this really is completly new and mindboggling stuff to me.

http://i1135.photobucket.com/albums/...aticlayout.png

Im extra stuck on the following and any info would be greatly appreciated.
1) Is this diagram correct as a start?
2) What type of hose can i use on FP and where can i get it from can only find stuff rated 25bar im after ½ inch sizing all round and also need all the various fittings?
3) Is the two buffer tanks big enough i read something about it needing to be 3 time volume of ram? How do i find volume of the tanks out?
4) What fitting could i use to fit on paintball/buffer tanks so its open/ not regulated could i just drill the centre of the PB regs?
5) What is the best way do the exhaust? I read about adding a QEV how would this operate ie no when to open/close?
6) With the 5404 burket valves what one (2) should i get.

I would just like to add I am completly aware of the dangers of high pressure Co2 and will make sure i have a full understanding of operating them safely and taking all precautions i can to handle as safely as possible.

Thanks in advance fo any help that you can give me.

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Originally Posted by helihurley

Hi all. I hope this forum is as friendly as it seems from the outside :wink: .

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Im extra stuck on the following and any info would be greatly appreciated.
1) Is this diagram correct as a start?

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It is correct, but you lack 2 parts. Dump valve and Pressure relief device (safety valve)

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2) What type of hose can i use on FP and where can i get it from can only find stuff rated 25bar im after ½ inch sizing all round and also need all the various fittings?

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I normaly use hydralic polymer , aramide reinforced hose. It's pressure rating is a lot over what we need, and it is light and can accept narrow bends. In other parts I use rigid steel piping (standpiping?) or even milled and turned collectors. Lighter and more purpose build (and therefor smaller) than use all steel hydraulic connectors and T pieces.
I'm lucky in that part that I worked in a hose manufactoring firm, and have good contacts there.

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3) Is the two buffer tanks big enough i read something about it needing to be 3 time volume of ram? How do i find volume of the tanks out?

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A CO2 tank has 1.5 times volume compared to rated weight. 20oz=600grams= 900 cc.
The 140mm bore 120mm stroke ram has a volume of 1.85L, so your 2 20oz tanks are on the small side.

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4) What fitting could i use to fit on paintball/buffer tanks so its open/ not regulated could i just drill the centre of the PB regs?

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Remove the valve, that's obvious, as the valves have a let trough of next to nothing.
If you can find connectors, you can fit those directly in the buffertanks. Other option is to rethread the neck with 3/8bsp or drill it out ,and rethread it with 1/2 bsp, and have then recertified.

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5) What is the best way do the exhaust? I read about adding a QEV how would this operate ie no when to open/close?

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Never seen a FP QEV, and it operates like a piloted 3/2 valve. Meaning you need a FP capable QEV and small 2/2 valve to use it. Best bet is to use a third Burkert.

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6) With the 5404 burket valves what one (2) should i get

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Normaly closed 1/2 bsp, brass body.

Thanks maddox10, great info!

I assume the pressure release valve will go in, or just after the main tank? Could this be just a burst disc or would it need to be a mechnical type valve?

How about the dump valve I guess that goes after the safty valve (main tank) and is that for releasing the pressure in the system on command (without firing the ram)?

So is my maths right in thinking I need a minimum of 5.55L, so lets say 6L. So two 1kg buffer tanks would be on the money at 6 litres. If thats the case is my 2kg main tank going to give me enough gas lets say 10 shots as an ideal.

If i were to get 5 port burketts would it be possible to route the exhaust to the unused side of the inlet valves to save on buying a third. If a third burket is required would it be a case of the inlet and exhaust working in oposites. i.e as one opens the other closes.

Thanks again for any info.

There was a picture posted just a few days ago about this actually, its for a low pressure system but its basically the same (obviously not components wise though) slightly different to your system, but from that you can see where the required safety valves go in the system :) .

EDIT: Forgot to post the link, Oops :lol:

viewtopic.php?f=111&t=4390

Thanks, so it goes dump valve then prv. Also that means a burst disc wouldnt do as a safty valve then. Does a fire exstinquisher have a safty release valve (useable to my needs) on it any where i assume it must have some means of protection.

Just thinking out load here but what is the purpose of having a safety release valve in the line of the system when the system is running full pressure. Full pressure systems are obviously aimed at giving you the most pressure available from the tank meaning (in my head at least) that over pressure would be unfeasable (spelling?).

http://i1135.photobucket.com/albums/...iclayout-2.png

Is this looking like it would work main thing im unsure of is will it exhaust quickly enough (or at all)

no that wont work burkerts are 2 port only, on or off. You will have to use one for exaust aswell, another £100 :shock: :!:

Hi, welcome to the forum! And yes. By the way did you get that ram off eBay ? Now I'm on holiday at the moment which unfortunately I cannot draw you any diagrams, also I'm only able to get on the forum once or twice a day but I'll do my best to answer your questions. When I get back back on the 20th i can draw diagrams, give you links, monkeys etc etc.

Fire extinguishers unfortunately don't have a prv in them, the burst disk will blow way before any other part of the fire extinguisher. A prv is very important as burst disks generally blow at 190 bar, burkerts are rated for 70 bar.
I see on your drawing your ram has 3 ports, I'd recommend using 3 Burkert valves, 2 inlet 1 exhaust. This is the easiest way. A well filled 2kg co2 bottle will give you 6 fires of that monster, if you want to acheive 10 flips you'll need to double it up with another 2kg bottle or use a larger bottle such as a 5kg. Other sizes of co2 bottle between 2kg and 5kg are hard to find. I know there was some 4.5kg scuba tanks adapted for robot use floating about a while back but they might have been sold by now.

Sorry for any typos, im tired and writing this on an iPhone

Cannot wait to see what design you come up with for the actual bot, I was making some offers on the ram and got down to about £175 but got unlucky when someone paid full price. Guess this is the ram lol. Should make a good machine but as just mentioned above you may need a bigger supply bottle or be really good at driving. When fighting other good flippers you'll use half of those flips self-righting.

Ahh, so now I know who mr rants is :)

A good trick is to pulse your valves when self righting so that you use less gas/don't hit the roof!

:proud: Mr R(obotic)Ants aka RAnts. I rarely get time to build, but now i'm pushing myself to get some feathers finished and parts for a heavy this year.

Anyway back on topic..

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Originally Posted by robotic_ants

Cannot wait to see what design you come up with for the actual bot, I was making some offers on the ram and got down to about £175 but got unlucky when someone paid full price. Guess this is the ram lol. Should make a good machine but as just mentioned above you may need a bigger supply bottle or be really good at driving. When fighting other good flippers you'll use half of those flips self-righting.

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There are a few of those 140mm monsters made by Kos (Tough As Nails), and 1 by me (only a small difference in setup). I know where most went originaly.

1 to Alex/ODT 02 (the smallest FP flipper heavy I know of, even smaller than Mute)
1 to BillE (that one returned to me and was sold recently)
1 to Swedemac/Mytril (a crusher, with 8 tons of instant force, it was a nasty one, but alas, it suuffered from some design flaws).
1 to Hammerhead Niels (that went in Hammerhead III, a flipper, suffering from to many compromises)

@Jonny
As far as I know, the 3 refurbished composite scuba bottles are still for sale.
And yes, you're right, 95% of the CO2 bottles have a burst disk in the valve that blows at 190-195 bar. Older types can have one that goes at 135 bar.

@ Helihurley, a Burkert will have enough flow to get the ram emptied inside a second. Just take the easy way out, buy 3 Burkerts.
There are some custom build FP 5/2 and 3/2 valves. One of those uses a Hitec BS805 servo to operate, all the others use low pressure to operate. But with pricetags over £350 to build them, and all of those hidden in dark places, or in active robots (TAN uses a Woody 3/2 FP valve)

Three burkets it is then.

hey jonny, yeh this would be your ram from ebay. Is your location in sussex as Me****le (incase you dont want everyone to no where you live) come up with four different places on the iphone search. I will be hoping to get to you at the weekend if I can but it might have to be Monday evening if that is allright with you are you back late or early Saturday. Any help you can give me on the ram would be great. Thanks.

At the moment I'm going to run the robot around with wheelchair motors (i know there no ideal but hopefully will be replaced with better eventualy). I already have a pair sitting on an electric wheelchair i aqquired a while ago. This wheelchair also has an electric chair height adjustment on it which is controlled by a moter driven shaft. Id say this must have some good power in it as it can lift 18st without even seeming to notice. My question then, could this be incorporated into some kind of secondary weapon on the bot maybe a grabber or somthing? Or is it just not strong enough to be any use on fighting bot.

Not many designs with 2 usefull weapons. Especialy not with such a weight intensive main weapon.
That 140mm ram delivers at 10 bar the nice 1.5 tons, and at 55 bar- FP- 8.4 tons. The frame has to cope with it, doesn't it?
And the linak is maybe a tad slow for a selfrighter.

Ill chuck it in the spares corner for future use then.

Is there a type of PRD that is prefered on here as i cant fing much info on forum as it returns no results if you search PRD or PRV. Did the google search and had a few things come up but strugling with the technical info (jiberish) they write up. I notice every one favours burket valves and wondered if there was a PRD equiverlant.

There is no Burkert equivalent for PRD's unfortunatly.

In the early 2000's Technobots had one , but that seems to be disappeared. Most people still use that, or use a custom made one.
In the end , it's not the technology that stops people to make their own, it's certification.

Good, I can show you how everything goes together if you want when you collect the ram. I get back very late on Friday so I'll be available all Saturday . Anytime before the 30th should be fine. I'll pm you my full address.

Thanks Jonny, once i have your adress i can work out best time for me to collect depending on where im working an ill let you no to see if it suits both of us.

I have been searching for PRV for hours now with no great lick best i could find was the following but it was designed to control water flow could this work.

http://www.danfoss.com/United_Kingdo...Valves/VRH.htm

I'm afraid that will be an expensive one, and large, if I can read the flow-specs correctly.
Also, i hope they can deliver it with a certificate and setpoint at 1000psi.

Searching in psi seems to be the trick with this one! I have found this is that what I need.

http://www.shoppressurewasherparts.c...e_p/971181.htm

Reading through this post when i said

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So is my maths right in thinking I need a minimum of 5.55L, so lets say 6L. So two 1kg buffer tanks would be on the money at 6 litres. If thats the case is my 2kg main tank going to give me enough gas lets say 10 shots as an ideal.

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I think i was being rather dim. I'm now thinking that I need 2x 2 kg buffers but as no one corrected me am unsure so could some one confirm fo me.

If it is the case that i need 2x 2kg bottle than this thing is going to be HUGE didn't quite realise how big it would have to be. Not really put off by this just a bit of an eye openor.

With designing a flipper bot is there a way of mounting the ram to the bot in a fixed possition (not on a pivot). I am thinking if the bottom doesn't pivot then the top pivot connected to the ram will bind up (which more than likey will rip it apart). Is there a way of having the flipper arm free mounted, just sittting on top of the ram. Obviously there could be issues with the flipper arm just wanting to rip itself off when it hits the top of its travel if i dont have some sort of buffer. As i havnt seen any robots in real life have no idea how this is genrally achieved. Any ideas very much welcome.

I really suggest you get yourself along to an event. You will be able to see them up close and have a chat with the teams and have a good look around how they have done things.

Thats a VERY good idea! Is there any events around the cambridge area (or within 100miles) coming up.

In the meantime any help with the above questions would be great.

Buffer tank wise aim for atleast double the volume of the ram, preferably triple. 2 1kg bottles will be 3l so slightly less than double, 2 2kg tanks will be 6l so slightly more than triple.

Yes most if not all fp heavyweights have the flipper arm detached from the ram (this is referred to as gravity style). Yes you can mount the ram to the base, the ram has 4 mounting lugs each with 2 m10 threaded holes, alternatively you could weld the ram to the base of your bot.

Thanks jonny.
I'm not going to be able to get the ram until after work Monday is that ok.

Can you give me any of the names of the FP flipper bots out there so I can have a butchers at there flipper design on the google?

'Gravity' Style flippers; Kronic, Iron Awe 5 & 6, Toxic 2, Ripper are the main ones i can think of.

A couple of pics of the insides of Kronic http://s1043.photobucket.com/albums/b43 ... ve/Kronic/ this is being changed at the moment though.

alan, ive problems with pc and cant signup for worthing, can you put me on the list, also tried to upload a few pics of toxic2 air system on to this page for helihurley but they are to large ! here is a weblink my brother has updated the site a little ! the pics are in toxic2 and if i get chance i will take some pics as i put it back together as i fix the burkerts (which have decided to die ) :(

www.toxicrobot.co.uk

will do Terry, are you some sort of Burkert serial killer? :lol:

yes :lol:
when i was at the shop i thought the same thing :!:
that it my new sware word now...........OH BURKERTS :lol:
bloody things are costing a fortune :angry:
really am thinking of some kind of l type ball valve system now.

Terry I hear you can get a Burkert repair kit for about £30

Yes I can get them I've only got 2 at the moment but 1 is for ed Wallace.
I will need the other for a spare at worthing, I can order more if you want
Just let me know.

Terry, if anyone wants the one your keeping for me they can have it. If not I will keep to our agreement. But it is currently surplus to requirements.

ok no problem ed, is apoc competing at worthing or kidderminster then ?

just a quick question, whats the maximum size a heavy can be? Now i know this information is somewhere on this forum already as I read it the other day, but for the life of me i cant find it now.

The old Mentorn rules give 1.4m wide, 2m long , height not defined.

Terry, won't be competing at Worthing. Got something in the pipeline, hopefully be ready for Kidderminster!