Chief Delphi - anybody know where to get some quick exaust valves or dump valves

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- - anybody know where to get some quick exaust valves or dump valves (http://www.chiefdelphi.com/forums/showthread.php?t=82866)

Re: anybody know where to get some quick exaust valves or dump valves

Note the GDC Q&A response that i linked to above.

Neither the question nor the answer include the word solenoid. The answer says "All non-KOP valves" used in the pneumatic system. The plug valve to relieve system pressure and flow control valves are allowed per the rules and other Q&A rulings, but I would be extremely cautious with any other type of valve.

As always, the only official responses come from the GDC via the Q&A. Ask if you're unsure if a specific type of valve is exempt from <R72-C> or not.

Re: anybody know where to get some quick exaust valves or dump valves

Read the second sentence of <R72-C>. C. Solenoid valves. All such valves must have a maximum ⅛” NPT port diameter, and a maximum Cv of 0.32 (if non-KOP valves are used, the team will be required to provide part documentation validating that the valves meet these constraints).

The only mention of "solenoid valves" is in the title. After that, it's "such valves" and "non-KOP valves". This would definitely be a non-KOP valve. This means that you have to bring documentation that it meets the constraints. If you bring documentation proving that it doesn't (or don't bring any documentation at all), the inspectors can make you change it. (Well, change it or sit out the entire competition.)

I would also note that multiple inspectors/rules readers/question askers have been (trying to) tell you that 1) this valve is illegal and 2) you could just use an open port.

Again, if you disagree with our interpretation, go to Q&A and ask them if this valve type is legal. We do read Q&A. If it is ruled legal, then you will want to bring the Q&A answer to competition with you, as the inspectors there will have the exact questions we do.

Re: anybody know where to get some quick exaust valves or dump valves

Quote:

Originally Posted by chmconkling (Post 922642)

...The rule only applies to soleniod valves

Chris,

Please post to the official Q&A for an answer to your question.

Regards,

Mike

Re: anybody know where to get some quick exaust valves or dump valves

Quote:

Originally Posted by chmconkling (Post 922642)

<R72>...The rule only applies to soleniod valves

Hi Chris,

If, as you say, <R72-C> applies only to solenoid valves, then <R72> does not explicity allow your dump valve. Therefore, your dump valve is prohibited by Rule <R71>.

If, on the other hand, <R72-C> does apply to your dump valve, then your dump valve must be Cv<=.32.

So either way, your 1.0 Cv dump valve is prohibited.

~

Re: anybody know where to get some quick exaust valves or dump valves

Quote:

Originally Posted by Ether (Post 922790)

no its not prohibited in any way shape or from because it is a off the shelf commercial part and there is absolutely no rule saying me cant speed up the act of a cylinder in a safe manner

The rules on this topic, analyzed.

Quote:

Originally Posted by chmconkling (Post 923280)

no its not prohibited in any way shape or from because it is a off the shelf commercial part

Setting aside the part about speeding up the cylinder (because there is in fact no rule on the topic, and there are multiple ways to do this):

COTS parts are legal under <R32> (provided that they satisfy budget constraints, etc.). I don't think anyone can argue that.

However, this is where we need to get into the pneumatics rules. I know you've at least scanned them. So let's take a closer look.

Quote:

<R71> To satisfy multiple constraints associated with safety, consistency, robot inspection, and constructive innovation, no pneumatic parts other than those explicitly permitted by the Pneumatic System Rules may be used on the ROBOT.

What that says is that anything pneumatic has to be explicitly allowed. I don't care if it's COTS or not. If it is not explicitly allowed, it is prohibited. Your inspectors would read this the same way.

In the following rule, I've removed the parts that do not apply to our discussion.

Quote:

<R72> In addition to the items included in the KOP, pneumatic system items specifically permitted on 2010 FRC ROBOTS include the following items. All included items must be “off the shelf” pneumatic devices rated by their manufacturers for pressure of at least 125psi, and used in their original, unaltered condition (except as required for assembly with other components).
B. Pneumatic pressure vent plug valves functionally equivalent to those provided in the KOP (Parker Part Number PV609-2).
C. Solenoid valves. All such valves must have a maximum ⅛” NPT port diameter, and a maximum Cv of 0.32 (if non-KOP valves are used, the team will be required to provide part documentation validating that the valves meet these constraints). Solenoid valves that are rated for a maximum pressure that is less than 125psi rating mandated above are permitted, however if employed, an additional pressure relief valve must be added to the low pressure side of the main regulator. The additional relief valve must be set to a lower pressure than the maximum pressure rating for the solenoid valve.
F. Pressure transducers, pressure gauges, and connecting fittings.

So, this is a list of exactly what is allowed. Anything on this list is legal. Anything not on this list is not. Also note that all pneumatic components must be COTS rated for 125 psi, and not messed with except as allowed elsewhere.

You're asking about a particular type of valve. This narrows it down to <R72-C>, which I will again quote below:

Quote:

C. Solenoid valves. All such valves must have a maximum ⅛” NPT port diameter, and a maximum Cv of 0.32 (if non-KOP valves are used, the team will be required to provide part documentation validating that the valves meet these constraints).

I have eliminated the parts about pressure rating due to the fact that they don't necessarily have any bearing on this discussion.

Notice that it says, "All such valves". Another way to say this is, "Any valve that is similar in function to a solenoid valve". If what you're looking for isn't similar in function to a solenoid, I don't know what it is.

Also note that you ARE looking for a valve. Note the last part that I quoted. I don't see any exception for valves that aren't solenoid valves. Except maybe the dump valve, which is covered elsewhere.

In other words, you're looking for an illegal component. Unless you and your team can show a Q&A and/or a spec sheet saying that this component is legal, you will not be allowed to compete with it on your robot.

I will make another post with some other possible methods to do what you're looking to do.

Ways to speed up a cylinder

We'll assume, for the sake of argument, that the inspectors have told you to fix the illegal valve that you've put on your robot. You still want to keep that performance, but you need something else. Now what?

1) Leave the port open. No rule says that you have to have a fitting in the port at all.

2) If you need the effect of an open port with a stop on it, you can put a mechanical latch/release on whatever the cylinder is driving and leave the port open.

3) You can put 2-3 solenoids in parallel on the outflow, and trigger them to open at the same time.

4) This one will need Q&A clearance, but it's been cleared in the past: Take a second dump valve (see <R72-B> for the part number) and rig it to turn under the influence of something else on the robot. Also see http://forums.usfirst.org/showthread.php?t=14196 for a similar solution.

BTW, I think you're looking for what is commonly termed a "dump valve". See http://forums.usfirst.org/showthread.php?t=14227 first question.