Vacuum

[NoRemorse]

Ok, I was wondering if it was legal to use a venturi style vacuum genorator. Its just a little box then when positve air pressure is blown over it, it creats negative air ressure at the other end. Probably wont use it anyhow, but it is somthing we are looking into and would like to know the legality of!

[Skabana159]

If you can make one with off-the-shelf parts, or ones that you have machined, and only motors from the kit, then yes, it would be legal.
However, if there was any motive force, in say the fan/blower, it would be an illiegal motor.

[NoRemorse]

What if it IS an off the shelf part all together

[KenWittlief]

you could probabally do what you are talking about, but I dont think it will create much vacuum.

in the past teams have used a pair of pnuematic cylinders to create vacuum. have a pressurized cylinder pump a second one to draw a vaccum at one end.

[NoRemorse]

Well, 2 points

Vanturi style is what they do in industry and create MUCH more vacuum, i just got home from prototyping

We were planning on using the cylenders, even thogh they create less vacuum, they reqire a NON-continuous flow

[BananaMango777]

you can also create a vacuum using a kit motor and a cam arrangement which repeatedly creates a draw/push stroke, then you retain the vacuum using a no-return valve on one side of the cylinder. This is something our team has been looking at this season
I think that this might be more successful than what you are proposing, I believe that some teams did this last year as well to develop a vacuum, with a fair amount of success.

[NoRemorse]

well, we need somthing with a quick vaccum produced to take out the air in our large cup, the cup is larg to allow for sloppy driving and positioning, lol

the ventri works WAY better than i thouht it would, you people should puick one up just to try it, ive seen them lift #30 boxes at my dads works. pretty impressive!

[KenWittlief]

yeah but what were they powered with? the compressors we have are pretty whimpy - something like 1/8 HP or less (rough guess) and they dont supply a large volume of air.

please dont let me discourage you- definately try the venturi and see how it works - Im only tossing out options for your consideration

[NoRemorse]

i know its not a good idea bc lack of volume of air, im just sayin, dont underestimate its power! try it out, i was REALLY impressed!

[andy]

I do not think that you have enough compressor "umph" to efficiently implement a venturi vacuum generator. I also would quicly discount centrifigal vac pumps (there heavy- upwards 100 lbs) and turbo molecular vacs (expensive-upwards $15000).

I would try to drive a pnumatic cylinder with a cam on a motor with one way valves that seems like the easiest, lightest, most cost effective solution.

good luck!
-Andy

[Rickertsen2]

Originally Posted by andy

I do not think that you have enough compressor "umph" to efficiently implement a venturi vacuum generator. I also would quicly discount centrifigal vac pumps (there heavy- upwards 100 lbs) and turbo molecular vacs (expensive-upwards $15000).

I would try to drive a pnumatic cylinder with a cam on a motor with one way valves that seems like the easiest, lightest, most cost effective solution.

good luck!
-Andy

But since one way valves arn't really legal either, you can use a double solenoid in place of one, as long as you know when the cylinder is extending and retracting. Rather that use a cam, why not put two cylinders parallel to each other and link them together, driving one, while using the other to generate a vacuum. As far as the practicality of generating a vacuum on a FIRST robot or the usefulness of doing so: impractical and useless, but its still interestign to discuss.

[TomWx]

Q&A hass said that Vacuums are not allowed, but suction cups are. As of right now, there are several different followup questions as far as using pneumatics and fans to create a vacuum. Tehse questions stand unanswered. It is clear however that venturi-style vacuum generators are not allowed.

[tenfour]

We tried this last year and got very little suction as a result of little air flow out of the compressor.

There is also a rule against custon pneumatics.

Why in the heck would you want a vacuum anyways?

[pras870]

To clarify, you cannot use an off the shelf vacuum. My team comtimplated this last year, and found that it was in fact illegal. Instead, we bought a festo suction cup, which created suction through a vacuum. Now I know this contradicts what I said, but it was not in fact a vacuum. We simply used 2 of the largest cylinders we could get (I think it was a 2" bore?), we used 1 to raise our arm, and the other cylinder was right next to it, with it's output valve connected to the cup. So simply, when you move the arm down, it created a vacuum/suction in the cup. However, you cannot keep constant pressure like this, so you basically had to keep pumping the arm up and down to keep the suction. I'm assuming you want to create some sort of vacuum to grip onto the big ball, and without using an actual vacuum, this simply isn't possible.

[NoRemorse]

That is exactly what we have done, and were planning to do from the beggining.