regulator on cylinder output?

I just need a sanity check - pretty sure this will work OK.

If we want a large force to extend an actuator, but don’t need one to retract it, could we plumb 60 psi to the solenoid, 60 psi from the solenoid A port to the back of the cylinder, and then plumb 60 psi from the solenoid B port to the secondary regulator, drop down to 10-20 psi and then to the front of the cylinder? It allows us to use less air per stroke (out-in), and since the solenoid still sees 60 psi we don’t have the pilot pressure limit on the downstream side of the regulator.

Is there a way for the air that goes thru the low pressure regulator to the cylinder, to bleed off for the next actuation?

In order to regulate the retracting you would need to use a separate solenoid that is regulated down prior to it going to the solenoid.

You could do it your way, but you are still using 60 PSI all the way up to the point your 2nd regulator is (which is pass the solenoid so you would still lose some extra pressure).

But it would ‘work’

You would have to use two different solenoids.

It would be easier to block the return port on the solenoid and use a light spring (like surgical tubing) to retract the cylinder.

You should probably consider a spring return cylinder as mentioned above. As alluded to by squirrel, you will need to do some tricky plumbing to ensure that when you pressurize the return the cylinder is at or below the reduced pressure. I’m not sure if the valve design makes this easy.

Gary,
The proportioning valves will lower the delivered air so that the return force is less but the piston still receives full 60 psi to keep it in place. The regulator may act slower than the valve approach. You would have to test the response of each one. The only advantage of the secondary regulator is slightly less air volume used.
However, this might be of interest…

<R76> “Working” air pressure on the ROBOT must be no greater than 60psi. All working air must be provided through one primary Norgen adjustable pressure regulator.

A Q&A check would give you a better answer. We have allowed more than one in the past. Specifically in the 2008 rules there were no limits on the number of regulators. 2009 had the same rules as this year.

As others have mentioned, a better option it two single acting solenoids, one plumbed for 60 psi, one plumbed for 10 psi. That or a spring return cylinder would work best. The obvious downside to the spring return being that the spring return force is going to decrease your extend force.

The problem with your proposed solution is that regulators are mostly one-way devices and don’t allow unrestricted flow backwards. So you’ll end up with the retract side of your piston still partially pressurized when you extend it again. Which might not be a problem for you, but wouldn’t be as optimal as having two single solenoids.

Al:
I’ve always read that as meaning you can only have one regulator that knocks your 120 storage down to the “safe” 60 pressure, but you could have further regulators after this main regulator if you had a reason. Basically, that you were only allowed one connection from your storage battery to the entirety of your valves/cylinders/etc. Q&Aing it can’t hurt, but I’d assume a secondary downstream regulator is legal until the answer came back.

Emphasis mine.

Not to nitpick, but the Festo valves are pilot operated and require a minimum of 20psi to operate (otherwise they leak).

I hadn’t thought about the regulator not allowing flow in the opposite direction (or at the very least metering it). Thanks.

Has anyone priced single solenoids? It hurts already to shell out $90 for a double, I’m guessing that they’re more than $45 each.

CD parts swap might help…we got a few solenoid valves from a generous team back East in 2008.

The monnier secondary regulators DO allow pressure to flow back through them. So it probably would work.

Thanks Ryan - it will be simple enough to test and see how/if it works.

Except air from a low pressure system never backflows into a higher pressure system…
To release pressure from the low side you’ll need a valve that releases to the atmospheric.

That’s what the solenoid does.
When the back side is pressurized to extend, the front side vents from the actuator back through the solenoid to atmosphere. Except in this case there would be a regulator in the line.

Yes, but after it vents the 60 psi in front of the reg then when they are equalized it will flow backwards through the reg and out the noid.