Adaptors and fittings for full pressure flipper

[evristow]

Fellow roboteers,

After 5 years doing spinners and some wedges in Brazil, I decided, since moving to the UK, to do a pneumatic featherweight.

Almost all components are defined and some were already bought, but I am heaving trouble defining the adaptors and fittings. What do people normally use for full pressure? I thought about using hydraulic adaptors from Burnett & Hillman rated for 350bar on a Aluminium manifold.

The system will be a custom, 65mm bore ram, with integrated valve. So the fittings for the Buffer tank will be 5/8~3/4 BSPP and for the main cylinder, to avoid icing, I thought about G1/8 or 1/4.

What are the experienced builders opinions on these matters?

Also I would like to take this opportunity to thank Woody for his resourceful website and all the forum members for the shared knowledge.

Regards,
Eduardo

[geeza]

Yes, you really can only look at hydraulic fittings to be able to cope with the pressure. I also do use custom Aluminium manifolds, a good grade of ally will help with getting strong threads. Personally I would use 1/4 fittings in the rest of the system, don't really know why probably got more that 1/8 at home to save spending money. Either way you should get the flow to the buffer ok.

[Mouldy]

hi again

What sort of setup is it? Buffer and valve as part of the ram? If thats the case i dont think you will need big flow pipes, even on the vent side of the valve you could get away with a Q.E.V straight on the vent port then small pipe to your firing valve..

If i was going to make a FP featherweight setup id go for the same pipe used in paintball guns.. its like low pressure plasticc push in pipe but its rated to 3000psi.

Ive only ever done heavyweight setups so weight was never much of an issue.

Id suggest if possible you stick to BSP fittings over here rather then NPT as you'd use in the states. just for ease of getting components.

Stick up a sketch of the system your planning so its abit easyer to help.

...Is that a freakazoid costume your wearing in your DP? lol

[evristow]

Thanks for the replies, I thought about hydraulic adaptors due to the pressure, nice to know that I am on the right track.

Ed, I was thinking about using 7050-T7651 or 7075-T6 due to their high tensile strength, what do you use?

David, The problem to use plastic tubing is the layout. On a small manifold it will probably fit the bottle, SPRV, Solenoid Valve, the RAM and, for the RFL, a gauge (), also it will be shock mounted. I will probably use those plastic hoses from the buffer to the dump valve, just need to find a place to put it! LOL! The costume is a custom made Freakazoid! My brothers always said that Dexter resembled me, so when the opportunity came, Freakazoid was reborn. Probably in July I will compete in Brazil dressed as such, the organizers normally wear costumes.

Back to the robot, the RAM exhaust is will be handled by the main valve, it is a really unusual design, its triples as admission, exhaust and check, depending on the position. It is similar to a QEV spud valve, mixed with Trent Elis' design, although different enough to be original Isn't it weird how ideas come to different people at the same time? I thought about a QEV integrated RAM just when I decided to move to the UK, but since my knowledge of high pressure pneumatics were really limited, it took a long time to perfect the idea.

Definitely all the fittings will be BSPP, just the paintball gauge that will be NPT - I think - but it will use a BSPP-NPT adaptor. The firing valve will probably be a FAS 04-211-101-40 12V 10W, triggered at 19.8~23.1V by a RC Switch. I still have to calculate the time needed to empty the main valve chamber through this firing valve and do some flow analysis for the whole system.

I found these CGA320 adaptors on eBay, does anyone knows were to buy something similar in the UK? Just in case I buy this, is it possible to chop the NPT thread and machine a new BSP G1/4 on it? I came across some CGA320 - BSP G1/2 adaptors from Air Liquide, proper to use with CO2, but they are not the swivel type, any suggestions?

Cheers,
Eduardo

[woody]

is it possible to chop the NPT thread and machine a new BSP G1/4 on it?

Yes to both the 1/8 and 1/4 ....simply run a bsp die over the npt thread ...not a perfect solution but ...IMO ..a perfectly safe solution.

http://www.teamonslaught.fsnet.co.uk/threads.htm

Regards Woody

[geeza]

I mostly use Alumec 89 from Blackburns metals, simliar tensile and hardness properties to mild steel, very good stuff.
http://www.blackburnsmetals.com/
But the grades you suggested are more than good enough.

[evristow]

@Woody,

Thanks once again! Your site and spreadsheet are really usefull.

@geeza,

This Alumec 89 have really nice specs! Added to my list, thanks again!

@All,

Does someone know a good BSP G1/8 ball valve to use as a high pressure dump valve? I searched Google but the choices are bulky or expensive. I was looking for something like the one on the below picture:



Also, can anyone confirm if Wizard of NOS Self Release Pressure Valves (SPRV) complies with FRA current rules? I managed to get their support and receive three of these valves.

Cheers,
Eduardo

[woody]

http://www.palmer-pursuit.com/cart/i...roducts_id=116

The relief valve looks like a good find ...but setting the pressure and certifying that you have set it correctly maybe a problem.

Cheers Woody

[geeza]

I use a G 1/4 ball valve as a dump on the heavy, got it from technobots years ago. It works although takes a while to dump all the buffer, would really like it to be a bit quicker. But don't see a problem with G1/8 for a feather.

[woody]

Finding an 1/8 ball valve rated for 1000psi is ...I believe ..the problem.