Re: Pnumatic Rules Suggestions/Gripes
 

At the time of my post I wasnt aware of such ASME codes. I didnt mean to question the itegrity of such codes. I was just suggesting a possible alternative(even though its not quite researched).

BTW we pressurize our water systems with air to check for leaks before we allow water to move through them. We pressurize them at around 130psi

Sorry for the confusion

-Pat

Re: Pnumatic Rules Suggestions/Gripes
 

Pat,

I didn't think you were questioning their integrity, I just figured you were ignorant. Most people are about such things. Heck, I went to engineering school and they didn't talk about the Boiler Code much there either. I didn't learn much about it until I started studying for the License Exam.

BTW being ignorant about obscure technical subjects is not a reflection of your general mental abilities. It just means you haven't been exposed to that area of knowledge.

Of course if you are exposed and refuse to take into account what has been learned, then you move from Ignorance to Foolishness. The book of Proverbs in the Bible has a lot to say about fools, none of it good.

Depending on the application, testing piping with air may or may not be a good idea. In this case the pressure is reasonable and it is not for an extended period. Using an ultrasonic leak detector could also help find problems like small leaks before you make a big mess. The air is much more likely to leak through small holes than water and is much easier to clean up than water. But if a fitting was very poorly soldered, then it might also become a projectile.

It all depends on your prefered risk. In new construction for a house it might not be a great idea. But if you're retrofitting a building with lots of wiring and expensive electronics, like a recording studio or radar station then the risk might be worth it.

Re: Pnumatic Rules Suggestions/Gripes
 

The valve WOULD NOT dump the accumulators, only depressurize downstream components. it does however create the below issue.This is one thing i overlooked, but that could be prevented by using a 3 position double spring return valve with a blocked neutral state. Of couse judging by the dissaray of valves that have come in the kits the last few years, I think FIRST already has a hard enough time getting valves donated without going into anything fancy. But then agian the whole point of my crusade is to allow us to use one of those if we should so desire. I saw some weird combinations of valves to achieve multipostitioning etc that could have been achieved with a single part if we were not soo restricted.
The company was probably PIAB, whom my company is a distributor for and whose products i work with on a regular basis. These are exactly what i am referring to. In fact i can say that you are probably referring to either an Mini Chip M(xx)LP pump or a P3010 series pump. The Mini Chip M(xx)LP pumps weigh only a 16th of a pound and is 16.5mm high, 61mm long, and 30mm wide. I havn't weighed a P3010 pump (which is a little more efficient and has an integrated filter, but a stack of 2 would probably be needed in a robot that relied heavily on vacuum). The Mini Chip M(xx)LP pumps can generate a vacuum of up to 24.1-inHg with various max flow rates and air consumptions depending on what you fill the "xx" in with, from a 55psi supply. The P3010 pump can generate a vacuum of up to 27.0-inHg from a 45psi supply and has a max flow rate of 2.97scfm while consuming 1.00scfm of compressed air.



As an addendum to my previous comments, about allowing a greater selection of actuators, i was really referring to two things.
1.) I do not think we should be given a list that says "you can use these sylinders and no others", rather i think we should be given guidelines similar to the allowable parts flowchart. An example of the absurdity of the current regulations was the issue where peope were pressing out the clevis pin to get their cylinders to mount how they wnated them to. This could ahve bene avoided entirely if FIRST had just let us buy the proper cylinders in the first place. Bimba offers their classic line of cylinders with about a dozen different mounting options. Someone find me a reason why we shouldn't be able to use a cylinder that bolts down instead of using brackets, or why we shouldn't be able to use one with a hole instead of a clevis pin? There us a reason why the Bimba Classic line catalog takes up 152 pages.(The classic line is the series of cylinders provided in the FIRST kit.)

2.) I am happy about rotary actuators being allowed this past season, and i saw some creative uses for them. There is one other actuator i think should be allowed, that is the rodless cylinder. For those of you who have never seen a rodless cylinder, Here is a link to a pic of one as an example. http://www.oylair.com/graphics/bimba...s_cylinder.jpg

I'm not saying that these things need to be incuded in the kit, only that they should be ALLOWED.



O one last thing. limiting selection ENCOURAGES BAD DESIGN PRACTICES. It teaches kids to use the wrong parts for the wrong purpose. The proper design practice is to use the right part for the job. I think that by allowing the proper parts, we would be raising the bar of FIRST stardards not lowering it. Robots would get more complex, not more like a lego set. We have only 6 weeks to build a robot. If we wasted less of that time on menial tasks such as hacking togther assemblies to use a standard cylinder as a rodless sylinder and focused more of our energies on important tasks, we could do alot more.

Re: Pnumatic Rules Suggestions/Gripes
 

Amen, James. If this goes through, no more miles of tubing to increase our air capacity for us!

But this means no more late nights spend checking every inch of tubing for leeks, just you and me, all alone in the dark technology room.

-Chris

Re: Pnumatic Rules Suggestions/Gripes
 

This is not really encouraging bad design practices. In many companies there is a restriction on increasing the spare parts inventory. The solution to this is to see what is available in the parts crib, our real life 'kit'. While this does not always produce the 'best' design, it does provide a workable design without increasing the overhead in the plant. If I really do need something new, I can.

Of course the distributors and all my suppliers think I need the latest and greatest and don't worry they stock it for me. Unfortunately at 1 AM when the machine is down, their stock room is not open immediately.

I must admit that the 'kit' at the plant is a whole lot bigger and does gives me more choices. :D

Re: Pnumatic Rules Suggestions/Gripes
 

If you are working for a pneumatics company this would be a great opportunity to talk to them about FIRST and possibly being a supplier.

One of the restrictions (a very good one) of FIRST is to make sure materials and parts of all robot building is accessable to all teams (not including custom design and fabrication of some raw materials). The parts we have in the kit and parts allowed from a list are based upon safety as wells as availability. In some cases parts are donated and often purchased for the kit or from a specific list from a specific supplier (sort of payback for their donation).

Keep talking about improvements to the kit and make sure you pass on all suggestions to FIRST - they listen to teams and experts on teams. Most of the recent changes are a result of suggestions like found here in this thread.

Re: Pnumatic Rules Suggestions/Gripes
 

Does anybody know who at FIRST i might try and talk to about this and how i can reach them?

Re: Pnumatic Rules Suggestions/Gripes
 

I'd try this guy:

Fred Hord of Hydraulic & Pneumatic Engineering Company, Inc. in Deerfield Beach, Florida.

I can't say yet how to contact him but I'll look some more. Couldn'tfind it. Ask FIRST. If that fails look to the people who organized the convention. Only names I can think of are Tonya Scott and Erin Rapacki.

He was the main speaker in the pneumatics workshop and helps organize the pneumatics part of the kit.

Re: Pnumatic Rules Suggestions/Gripes
 

That is a problem when you have a 2"x24" piston and a 2"x12" piston on your machine. It takes our system a quarter of the match to charge fully(thank goodness we only need it once or twice a match). That is also the reason we have developed the recycle circuit.

What Im wondering is if there is a solonoid valve that can be used for a multiposition pnuematic system(IE:one valve instead of two or more). I ask this because using two solonoids is really draining on a new or small teams resourses and it would simplify my pnuematic boards quite a bit :rolleyes:




-Pat

Re: Pnumatic Rules Suggestions/Gripes
 

Another thing that I have been pondering about is the use of different kinds of pistons...This year the rotary device was added. There are many different pistons out there and many would be useful...an example would be a double ended piston (lets see if i can do art....)(sorry for the lack of terminology)

---||||||-------- <---one direction

-------|||||||--- <---the other direction


For pistons like these i see enormous value and an almost endless design advantage. It would simplify many of our current pneumatic systems and open a world of new ideas/options teams have.

-just some thoughts to ponder upon

-Pat

Re: Pnumatic Rules Suggestions/Gripes
 

I was at VCU, and we (617) were the only team to use suction that I remember. We had a dustbuster mouth (right where the motor-fan part is), but we replaced the original motor with a legal one (fisher price, i think) and sealed a pie pan onto the mouth. The ball could be lifted, but if the robot moved, the ball would fall off.

Re: Pnumatic Rules Suggestions/Gripes
 

There is an on line video for pneumatics found at:
http://www.usfirst.org/robotics/2003/online.htm

Also this link to suppliers for 2004 has a Pneumatics questions and problems number.
http://www2.usfirst.org/2004comp/200...r_Contacts.pdf

I actually call the number last year as I was new to pneumatics and I was suppose to show the students how to do it. The people were really helpful. hope that this helps some people out.

Re: Pnumatic Rules Suggestions/Gripes
 

This is against the rules. Read 5.2.1 for the specific statement, and then also refer to the Q & A on-line sessions from 2004. The specific question was asked about using pneumatic tubing as a reservior - answer = NO.

Re: Pnumatic Rules Suggestions/Gripes
 

I actually thought the pneumatics rules were quite open and not really very restricted, as some of you seem to think. Given last year was my rookie year, but my dad has also sold pneumatics for 20 years, so i do have some previous experience and exposure to them.

The restrictions that they do have only make sense - you halfta have standards set for things like compressors and accumulators or there's no way that it could even be a remotely fair playing field. I can sympathize with needing more or larger air storage, but this should still be something that is standardized, either with having an additional clippard tank or two larger tanks - not by just allowing people to pressurize whatever they can get ahold of.

As far as actuators are concerned, Section 5.2.9 <R54> states "There is no limit to the number of solenoid valves, air cylinders, and connecting fittings you may use on your robot. They must, however, be “off the shelf” pneumatic devices rated by their manufacturers for pressure of at least 125psi."

That rule states there is no limit to the number of pneumatic devices, so long as they are commercially avalible and rated for at least 125psi. This would include rodless cylinders, rotary actuators, pneumatic grippers, multiposition cylinders, and countless solenoid valves, for these are all avalible from any number of different manufacturers. I don't see how that seems restricted.

FIRST dosen't half to supply everything that you can use in the kit, and we shouldn't expect them to - although they do give you plenty to work with. Pneumatic actuators are an example, they give you some to work with, but that dosen't mean you are limited to what they give you.

Our team had a number of complexities in our pneumatic system last year. We didn't have any specialty actuators, but we did run both 30 and 60 psi in order to save air where we didn't need high force. We even had two cylinders which we could switch between the two pressures by using a solenoid valve backwards and plugging the exhaust ports, this would let us raise our hook while saving our air for when we needed it to actually hang. We had 2, three position solenoid valves and we also had an air filter hooked up just after our compressor to help eliminate some of the moisture we were getting built up in the air system, certianly not something FIRST robots usually, or mabye even have ever had - but it is standard in industry application.

Anyways, thats just a few of my thoughts
Feel free to comment back or correct me if i may have misspoke,

Jeff

Re: Pnumatic Rules Suggestions/Gripes
 

This is mostly correct. <R54> also limits where you can get the solenoid valves and air cylinders thus eliminating the majority of actuators on the market. The Flowchart is very strict, the answer is NO for just about any pneumatic device. Unfortunately the air filter you used was also not allowed as it is not a connector or an approved device. It is a great idea and something that is installed on all equipment in my plant.

Pneumatics, and electrical, have been the most tightly controlled areas of the robot. The reason is safety. Many teams have members with experience in these areas. But think of the rookie team consisting of one science teacher and students who never worked with air before. The rules are their roadmap to prevent accidents.