HELP: Internal Solenoid Leaks Killed Us!

[de_]

We went from a major contender to losing the semi-finals for our alliance when our robot ran out of air due to increasing severe air leaks through-out the day this past weekend. We have one more chance next weekend but obviously our robot is in quarantine . We had already seriously tightened all brass fittings to the point soapy water did not find any leaks. We have yet to see any "push in" air hose fittings leak. We had tightened all the pilot valve screws and the manifold screws. Our best guess is we had joint seal leaks and or internal valve air leaks. But that was hard to confirm with soapy water as the valves were vertically mounted immediately above the spikes which could not get wet.

We had a number of people at the regional say that they had suffered from (more than one )"blown" solenoids (implying seals) and or leaking porous castings.

What is everyone elses experiences ? Since we are operating these values close to 1/2 their rated pressure and they are largely brand new and have only an hour of use (ie pressured), I am surprised we are in this position.

Anyone know how waterproof the pilot values are ? We would love to be able to dunk the complete solenoids for 10 seconds in a water tank under pressure with capped output tubes and tubes on the exhaust valve in a way that water can run up them but leaks from them would be obvious. That way all possible leaks will clearly be visible.

Anyone have any experience with the Festo valves ?

Our plan is to come in with tested spares, a standalone test compressor (with no reserve tanks: shows leaks much faster), replacement gasket kits.

Any other suggestions ?

There is another thread on leaks but for some reason its closed.

[Racer26]

If you're using the plastic festo valves, thats your problem. We had a MAJOR air leak at Waterloo this weekend because of one of those piles of crap. We hate them, and as a team that heavily utilizes pneumatics every year, their quality definitely leaves something to be desired. SMC all the way!

[ebarker]

Ditch the Festos !!

Last year we had 50% failure rates.

This year it was OBF.

They are just annoying.

[RyanN]

Indeed, the Festos are not worth the hassle. We tried to use then the year before last for our shifter, but after the first time it fired, it would not fire again. I know the spike was delivering power to them, and we had 2, and both did the same thing. I'm also not a fan of plastic for pneumatic parts. The Festos are too large as well.

[Daniel_LaFleur]

Originally Posted by de_

We went from a major contender to losing the semi-finals for our alliance when our robot ran out of air due to increasing severe air leaks through-out the day this past weekend. We have one more chance next weekend but obviously our robot is in quarantine . We had already seriously tightened all brass fittings to the point soapy water did not find any leaks. We have yet to see any "push in" air hose fittings leak. We had tightened all the pilot valve screws and the manifold screws. Our best guess is we had joint seal leaks and or internal valve air leaks. But that was hard to confirm with soapy water as the valves were vertically mounted immediately above the spikes which could not get wet.

We had a number of people at the regional say that they had suffered from (more than one )"blown" solenoids (implying seals) and or leaking porous castings.

What is everyone elses experiences ? Since we are operating these values close to 1/2 their rated pressure and they are largely brand new and have only an hour of use (ie pressured), I am surprised we are in this position.

Anyone know how waterproof the pilot values are ? We would love to be able to dunk the complete solenoids for 10 seconds in a water tank under pressure with capped output tubes and tubes on the exhaust valve in a way that water can run up them but leaks from them would be obvious. That way all possible leaks will clearly be visible.

Anyone have any experience with the Festo valves ?

Our plan is to come in with tested spares, a standalone test compressor (with no reserve tanks: shows leaks much faster), replacement gasket kits.

Any other suggestions ?

There is another thread on leaks but for some reason its closed.

First off, as an engineer from Parker (Festos competitor) I can tell you that the Festo valves are far better than what the posts above will lead you to believe.

Most leaks with the Festo have to do with the quick compression fittings. Thise fittings require that the tube be cut square to the side of the tube and straight. If they are not then they will leak and they tend not to be easy to spot (for those that don't have a LOT of experiance with them). I would suggest popping each tube out of the valves compression fitting and recutting the tubes, making sure they are cut square to the side of the tubing, and then reinsert into the festo valve compression fitting.


Now on to how to test for internal leak of the Festo valve.

With the valve deenergized:
Apply pressure to the common (supply) port, seal off the Normally open port, and seal the normally open dump port with your thumb. If you can feel pressure building against your thumb then there is an internal leak against the normally open seat ... and the valve is bad.

With the valve energized:
Apply pressure to the common (supply) port, seal off the Normally closed port, and seal the normally closed dump port with your thumb. If you can feel pressure building against your thumb then there is an internal leak against the normally closed seat ... and the valve is bad.

If niether builds pressure then the valve is good.

One last thing, The Festo valves require 30 PSI to fire. If 30 PSI is not available on the supply port the spool within the valve will not move or worse, may move 1/2 way and cause a leak between the common and the dump ports. This could also be your issue if the pressure falls below 30 PSI during the valves operation.

Good luck.

[Racer26]

We are talking about the plastic festo valve included in the kit of parts since 2004. Its only got 4 ports, a pressure, NO, NC, and exhaust. This limits its creative uses by creative exhausting, and we also have found that in the FIRST environment, they tend to work for a short time, and then leak. It does not appear to be an issue with the compression fittings, but I will agree that these are a common source of air leaks in a system, especially when the lines are not cut square.

[ebarker]

Originally Posted by Daniel_LaFleur

Now on to how to test for internal leak of the Festo valve.

With the valve deenergized:
Apply pressure to the common (supply) port, seal off the Normally open port, and seal the normally open dump port with your thumb. If you can feel pressure building against your thumb then there is an internal leak against the normally open seat ... and the valve is bad.

With the valve energized:
Apply pressure to the common (supply) port, seal off the Normally closed port, and seal the normally closed dump port with your thumb. If you can feel pressure building against your thumb then there is an internal leak against the normally closed seat ... and the valve is bad.

I like the Festo valves when they work, but ....

Last year we had to go through 4 units to get 2 good units, using the above tests. And this year it was DOA. I was planning to buy some spares but gave up on the idea after the DOA.

Next year we will try again.

[R.C.]

can anyone tell me how to wire up the smc double solenoids and how to put them together please, the festos we have are not working.

[RyanN]

Originally Posted by rc_cola1323

can anyone tell me how to wire up the smc double solenoids and how to put them together please, the festos we have are not working.

I personally haven't ever put one together, but I know there are 4 parts you need:

The screws
Top solenoid part
Bottom Inlet, Outlet part
Gasket

I imagine the easiest way would be to insert the screws into the top half, then put the gasket on, then place it on the bottom half, screw the screws in, and call it good. This may or may not be good, but I know with oil filters, you should put some oil on the rubber gasket part to seal it better, so adding a little oil to the gasket may help it seal better.

As for wiring, I do know how to do that! The attachment below shows a diagram I drew to help another team a while back. It has more information than you asked for, but it should still help you out.

EDIT:
From Daniel_LaFleur from a few posts down.

Don't add oil as some oils will attack the seals. Use a silicone grease like Krytox or a barium based grease like Parker O-Lube.

[Amanda839]

Rosie had a major pnuematics leak with our Norgren regulator, there made to handle 50psi but according to the manual we were allowed to set it to 60 psi, well didnt, we replaced it with the Monnier Regulator and our system works good. We further investigated why the Norgren had malfunction, and our conclusions were that this years regualtors were only hand tight and the outside was more of a 12 sided polygon than the many ridges of last years Norgin, anyway we replaced it to the Monnier and it works good

[Tristan Lall]

Originally Posted by Amanda839

Rosie had a major pnuematics leak with our Norgren regulator, there made to handle 50psi but according to the manual we were allowed to set it to 60 psi, well didnt, we replaced it with the Monnier Regulator and our system works good. We further investigated why the Norgren had malfunction, and our conclusions were that this years regualtors were only hand tight and the outside was more of a 12 sided polygon than the many ridges of last years Norgin, anyway we replaced it to the Monnier and it works good

Did you follow <R98>, which requires a Norgren regulator before any Monniers?

[Daniel_LaFleur]

Originally Posted by RyanN

I personally haven't ever put one together, but I know there are 4 parts you need:

The screws
Top solenoid part
Bottom Inlet, Outlet part
Gasket

I imagine the easiest way would be to insert the screws into the top half, then put the gasket on, then place it on the bottom half, screw the screws in, and call it good. This may or may not be good, but I know with oil filters, you should put some oil on the rubber gasket part to seal it better, so adding a little oil to the gasket may help it seal better.

As for wiring, I do know how to do that! The attachment below shows a diagram I drew to help another team a while back. It has more information than you asked for, but it should still help you out.

Don't add oil as some oils will attack the seals. Use a silicone grease like Krytox or a barium based grease like Parker O-Lube.

Your wiring is correct of you want to use it to power 1 side or the other as long as your output to the spike is -1 or 1. Setting the spike to 0 will not move the spool and the valve will not change (this can be used to your advantage).

SMC valves also require 20 PSI for the spool move.

[ebarker]

Originally Posted by Daniel_LaFleur

Use a silicone grease like Krytox or a barium based grease like Parker O-Lube.

Is the grease required ?

[RyanN]

Originally Posted by ebarker

Is the grease required ?

No, but it reduces the chance that you will have a leak.

[Bochek]

just wondering, what team number?