Quick Exhaust Valves - Illegal !?!?

[Shu]

Originally Posted by MrBasse

I'm curious to hear the answer as we have used a 90 degree fitting with no tubing to vent to atmosphere while using gravity to return the cylinder for the last two years. We used it on our ball pickup in 2012 and our climbing arms and disc dump in 2013. Both years we passed inspection at two districts and MSC.

Also, if you put the opening in the cylinder out of the way of a place where dirt and dust can accumulate, there is very little risk of pickup up any debris.

We have done it for years this way also with no issues. I read through the pneumatic rules and did not see anything pertaining to this.

[JesseK]

There is no rule which states that the open ports of a cylinder must be attached to the solenoid, which means that there is no reason venting directly to the atmosphere is illegal.

If it were made illegal via a new rule, I'd be pretty upset. We are working on a design that uses pneumatics and hasn't been seen in FIRST (or at least in the many designs I've seen or studied from 2008, 2010, or 2014). It's pretty simple, but relies on the pressure venting directly to the atmosphere. We could possibly overcome a ruling, but only by moving to more expensive solenoid valves.

[cmwilson13]

Originally Posted by JesseK

There is no rule which states that the open ports of a cylinder must be attached to the solenoid, which means that there is no reason venting directly to the atmosphere is illegal.

If it were made illegal via a new rule, I'd be pretty upset.

my thoughts exactly

[sanddrag]

Originally Posted by JesseK

There is no rule which states that the open ports of a cylinder must be attached to the solenoid, which means that there is no reason venting directly to the atmosphere is illegal.

Which is why I can't understand why quick exhaust valves are illegal. Perhaps it is the difference in venting near-atmospheric pressure to atmosphere, as opposed to venting 60 PSI to atmosphere? Still, I don't see the danger in it.

[FrankJ]

I view the new solenoid valve rule as a positive step. My impression is the GDC is keeping the pneumatics restricted to keep the robots safe & to simplify the inspection process.

This was done in 2010. No comment on if it would be legal in 2014

Posted by 2010FRC0476 at 01/25/2010 10:52:27 am
Can we use plug valves, Parker model # PV609-2 as allowed in Rule R72, instead of
solenoids to activate and exhaust pneumatic cylinders? We would rotate the plug valves using
pneumatic 90-degree actuators and a custom-made bracket between the pneumatic actuator
and the plug valve handle. Or we would turn the plug valves using HS322-HD servos or the
Denso window motors.
Re: Plug Valves Instead of Solenoids
Posted by GDC at 01/28/2010 12:03:45 am
There is no rule that would prohibit this.

[yara92]

my thoughts exactly

[martin417]

Originally Posted by Ether

Has anyone run that by Q&A? Ya never know...

There is no rule against this, and unless they create a rule outlawing single acting cylinders (which is what this would be) there won't be. I cannot imagine the GDC suddenly outlawing more than 50% of the available cylinder on the market.

[cgmv123]

Originally Posted by martin417

There is no rule against this, and unless they create a rule outlawing single acting cylinders (which is what this would be) there won't be. I cannot imagine the GDC suddenly outlawing more than 50% of the available cylinder on the market.

I wouldn't assume that. The GDC outlawed almost all of the available wheels on the market in 2009. (Not that I expect them to do that again...)

[martin417]

Originally Posted by cgmv123

I wouldn't assume that. The GDC outlawed almost all of the available wheels on the market in 2009. (Not that I expect them to do that again...)

Yes, as part of the game, and at the beginning of the season.

[Madison]

Forgive a ridiculous question, please --

What type of device, generally, is that which is described as a "pressure vent plug" in Figure 4-15 in the manual? (http://frc-manual.usfirst.org/viewItem/181#4.10)

This is what we all use to vent the system of pressure and does not appear to be among those items listed in R77-F.

What am I missing?

Derp -- I'm missing part B.

So, then, the question becomes -- what makes this valve functionally different from a ball valve / quick release valve?

[FrankJ]

What am I missing?

Functionally, it is just like a ball valve. Except the rules call it a vent valve with the functional intent to dump all air out of the system. At least that is how I read the rules & Q&A comments.

The real question becomes how do you isolate the systems you use an off board compressor since you are apparently not allowed to use valves?

I really don't envy the GDC in all this.

[DavisDad]

I'm easily confused and think we're mixing names of devices. Here're some references:

Pneumatic Valve Types

A GUIDE TO UNDERSTANDING PNEUMATIC
DIRECTIONAL CONTROL VALVES

Wikipedia: List of valves

McMaster Carr

[amesmich]

For the questions above here's a good video explanation
http://www.youtube.com/watch?v=X5SVF7TV8w4


As for my two cents, I agree. I think the GD is unnecessarily limiting with pneumatics. I don't agree that they want to "keep the bots simple" or make it easy for inspection. IF that's the case then I think its wrong and goes against the good portion of what FIRST is about.

This is one area I think FIRST could improve. Remove some of the restrictions that limit legitimate design ideas. Safety can still be maintained. Its done everyday it can be done in a first event.

[Anthony Galea]

Originally Posted by Christopher149

Since our prototype is currently using a fitting-less downstroke, I went ahead and asked.

Looks like we have a reply:

Q. Is there any rule that prevents a port on a pneumatic cylinder from venting directly to atmosphere, without any fitting or tubing, so that only one direction of motion is powered?
2014-01-19 by FRC0857

A. No.

So this means venting to the atmosphere is legal. Now we know our shooter is legal!

[DavisDad]

Originally Posted by 3175student17

Looks like we have a reply:



So this means venting to the atmosphere is legal. Now we know our shooter is legal!

3175student17- thanks for the information; much appreciated!