pic: It's systems integration time!

[trilogy2826]

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.

[ToddF]

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.

[EricLeifermann]

Originally Posted by ToddF

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.

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

[apalrd]

Originally Posted by ToddF

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.

Why are they illegal now?

They meet all the requirements of R89.

[ToddF]

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.

[EricLeifermann]

Originally Posted by ToddF

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. If it were functionally equivalent, there would be no reason to use it. (Other than cost and availability.) 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.

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

[ToddF]

Originally Posted by EricLeifermann

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

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.

[amesmich]

Originally Posted by ToddF

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.

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.

[AGPapa]

Originally Posted by amesmich

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

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

Originally Posted by trilogy2826

With a normally closed action, you'll never have to remember to close the valve again.

[apalrd]

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.

[ToddF]

Originally Posted by apalrd

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

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.

[Sparky3D]

Originally Posted by ToddF

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.

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.

[EricLeifermann]

Originally Posted by Sparky3D

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.

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.

[ToddF]

We must have cross posted.

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

[Nate Laverdure]

Originally Posted by ToddF

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.

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.