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That is really clever. It's amazing how such a simple thing can make you so happy.

One valve that I found a few years back is McMaster 6790T42

http://www.mcmaster.com/#catalog/120/481/=qkrfx0

Under Brass push button valves. With a normally closed action, you'll never have to remember to close the valve again. I think this would still work well with your mounting method.

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That's really cool. I love the idea of using a spring loaded valve for the dump valve. I hope that someday they will become legal to use.

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We've used the part Jake mentioned for the last couple years with no issue.

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Why are they illegal now?

They meet all the requirements of R89.

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It violates R77.B:
"The only pneumatic system items permitted on 2014 FRC ROBOTS include the items listed below. ...
B: Pneumatic pressure vent plug valves functionally equivalent to those provided in the KOP."

A momentary push button electrical switch is not functionally equivalent to a toggle switch, which must be actuated in both directions.

A spring-loaded single-acting pneumatic cylinder is not functionally equivalent to a double acting pneumatic cylinder, as it returns to its retracted position without actuation.

A spring loaded push button pneumatic valve is not functionally equivalent to a rotational ball valve, which must be actuated in both directions. For the purposes of a dump valve in a FIRST robot, the functionality of being spring loaded makes it better than a ball valve. From an air flow perspective, they may flow the same, just as electricity doesn't care whether it is switched by flipping a switch or pushing a button. But, to the operator, they are very different. If it were functionally equivalent, there would be no reason to use it. (Other than cost and availability.)

I suggest a question to Q/A. I'd love for them to rule the push button dump valves legal.

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Do they both not serve the same function? They both allow and prevent the release of air pressure.

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One allows you to forget, and leave it permanently open. The other does not. They are not functionally equivalent.

If one component includes a function which differentiates it from another, and makes it more desirable for a particular application, by definition, they are not equivalent.

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1. Any valve can be forgotten about and be left open or closed so I dont see the difference there.

2. No they are not equivalent but they are FUNCTIONALLY equivalent. They serve the same purpose via slightly different methods. More than one compressor is leagal for first. They are both FUNCTIONALLY equivalent but they certainly are not the same one is heavier and can be viewed as a disadvantage.

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No, the valve that Jake linked to (the one we're discussing) closes by itself.

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Guys, you're over analyzing this.

A manual valve is a valve, it releases the pressure in the system when manually actuated. IMHO, the function is to release pressure when actuated manually, and both valves do that.

Not sure why we have to read so hard into this.

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R77B does not apply to compressors.

See R77J and R79.

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I realize that I was making a general point of functional difference.

I didnt realize the valved closed by itself. I agree with the above post, reading too much into it.

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I'm concerned with whether spring loaded push button valves are legal because there are some really cool things that can be done with them. This year there is no rule that says pneumatic cylinders must be actuated by solenoid valves.

For example, a small pneumatic cylinder actuated by a legal solenoid valve could be used to push the button on a high flow spring loaded push button valve (McMaster 6859K31 for example) that fires a pneumatic catapult.

Another example would be a weight which is held up by a motor that has power as long as the robot is operating. In case of a dead robot, the weight drops on a push button valve, which ejects the ball from the robot.

edit: Never mind. Just found Q235.

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Actually, the Q&A already dealt with the alternate uses of manual valves (Q235). You are only allowed one, and it can only be used to vent pressure for the system.

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Answer of Q235

"No. Per R89 only one pressure vent plug valve may be used on the ROBOT which, when manually actuated, must vent to the atmosphere to relieve all stored pressure."

Bolded for my emphasis, doesn't state that the valve must be manually actuated to prevent air from being relieved. Though this question was asked about a different topic, its answer allows for spring actuated relief valves.

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We must have cross posted. :)

Full disclosure: We are going to install one and let the inspectors decide.

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You can accomplish this with a single-acting solenoid. In the case of a dead robot, the coil is deenergized and the opposing spring throws the valve.

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Well, we finally got an authoritative answer. We installed a push button dump valve, and it passed inspection at both of our regionals. At the championship, the inspector flagged it. The question went to Al himself. Al said that part of the function of the valve was that the handle visually indicates whether the valve is open or closed. It's not immediately visually obvious with a push button valve if the system is vented. Looking at the pressure gauges doesn't count. (I heard this second hand, as I was on a plane when the robot was being inspected.)

We swapped valves and competed with a valve with a handle.

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For now, this would not be legal. I had several teams remove the springs at Champs. We (volunteers) and everyone needs to know that the pneumatic system is open/vented when working on or near your robot.