Two regulators for one piston

[gpetilli]

Originally Posted by Edxu

Hi CD,

We're wondering if it is legal to use two pressure regulators to actuate the extension and return strokes (A and B inputs) of a piston at different working pressures.

Thanks

Al,

I don't think the original question actually tied the outputs together. Are you sure this would not be legal?

[billbo911]

There is also the other option: One valve for extension, the other for retraction.

Is that legal? The two feeds are separated by the disk in the cylinder and not tied together.

[matthew_martin]

I think the best option would be to use Pressure Flow Regulators that are actually fittings that mount on the cylinders themselves. I know you can order then from AndyMark here: http://www.andymark.com/product-p/am-2032.htm
They look kinda like the things in the picture.

[JamesCH95]

OP- you may consider spring returns added on, spring return cylinders, or a smaller cylinder to retract the whole mechanism if your idea doesn't pan out.

As I understand it one of the two solenoid outputs would have a regulator between the solenoid and the air cylinder. The outputs of one solenoid are connected to the air cylinder(s) and it would seem legal, in my non-expert opinion.

Originally Posted by billbo911

There is also the other option: One valve for extension, the other for retraction.

Is that legal? The two feeds are separated by the disk in the cylinder and not tied together.

R90
The outputs from multiple valves may not be plumbed together.

Now... there are two ways to interpret this... either the outputs cannot be connected to the same cylinder, or they cannot be connected to the same port and/or tee-d together. Our resident expert, Al, interprets it as they cannot be connected to the same cylinder.

In 2010 that rule did not exist (as far as I know) and my team did exactly this, and it was inspected as legal.

Originally Posted by matthew_martin

I think the best option would be to use Pressure Flow Regulators that are actually fittings that mount on the cylinders themselves. I know you can order then from AndyMark here: http://www.andymark.com/product-p/am-2032.htm
They look kinda like the things in the picture.

The intent, I assume, is to reduce air usage, not to slow down the mechanism. I assume 610 is going to have an awesome air-powered shooter and they want to get more shots out of it in each match.

[Edxu]

Originally Posted by JamesCH95

Now... there are two ways to interpret this... either the outputs cannot be connected to the same cylinder, or they cannot be connected to the same port and/or tee-d together. Our resident expert, Al, interprets it as they cannot be connected to the same cylinder.

Thanks, this is what we were worried about.

Could anyone else confirm if that is illegal or not?

[gpetilli]

Originally Posted by Edxu

Thanks, this is what we were worried about.

Could anyone else confirm if that is illegal or not?

I think your original post is legal, but Al is the CD rules guru (and a good one at that). Given the uniqueness of this, you may want to submit an official Q&A.

The way I interpret your question is:

-------------- portA
|
-
valve |
-
|
----2nd Reg -- portB

you only have one valve and its outputs are not connected together (other than through the piston, which is typical). So the real question is can you have a regulator after a valve (or can you have two working pressures). I don't see a rule that prevents this - and it should help you exhaust the air out of portB quicker.

[Bob Steele]

I don't see why this would be illegal. You are allowed to use regulators/accumulators anywhere you wish. You just have to have the mandated one that regulates the working pressure of your system down to 60 psi. Beyond that point you can have regulators anywhere you wish. Of course all they could accomplish would be to lower the pressure into a given cylinder or portion/stroke of a cylinder.

You are not plumbing the outputs of 2 solenoids to the same cylinder.

As always, your best bet is to ask in Q/A

Al may have misunderstood your initial question. His statement is entirely correct but it doesn't answer your specific question.

He is the Chief Robot Inspector... and not just a "Rules Guru" by the way

[Bill_B]

Originally Posted by matthew_martin

I think the best option would be to use Pressure Flow Regulators that are actually fittings that mount on the cylinders themselves. I know you can order then from AndyMark here: http://www.andymark.com/product-p/am-2032.htm
They look kinda like the things in the picture.

Matt could have shown the other side of the fitting which has the symbols for the flow control meter out valve on it. There is also a flow control meter in valve available. I'll try to attach pictures and symbols.

[gpetilli]

Originally Posted by Bill_B

Matt could have shown the other side of the fitting which has the symbols for the flow control meter out valve on it. There is also a flow control meter in valve available. I'll try to attach pictures and symbols.

A flow control valve will do the opposite of what is desired. A flow control valve does not change the final pressure, but changes how fast the air can enter/leave the cylinder and therefor slows down the travel. He is trying to exhaust the air in the cylinder faster. Since we are limited by the diameter of the valve, he is trying to limit the pressure on the exhausting side, and therefor the amount of air that needs to be expelled. To move the piston, you need more pressure on one side than the other, which we do by venting one side - he is trying to start from a more favorable delta pressure.

[fsgond]

Our team was looking at a similar question a few days ago. Originally I was going to go the route of 1 valve on each side of the actuator, one at 60psi and one at 10psi. We found that as other have suggested that the http://www.andymark.com/product-p/am-2032.htm would be an easier way of doing things with the same goal achieved. I think either would work fine, but you would need to follow the rules about multiple regulators, I believe that there are some additional restrictions, such as having another gauge.

[gpetilli]

Please try the experiment. What you will find is that the pressure is identical on both sides of the needle valve. These devices restrict the movement of air by making the orifice smaller. They limit the maximum kinetic energy (flow) without changing the final potential energy (pressure).

A flow restriction could be what you want if you are happy with the maximum shooter distance and what you are trying to do is create a slow piston velocity for a shorter shot (soft pass).

It will not work for the original question where they were trying increase the maximum velocity by presenting different pressures to either side of the piston. Asymmetric pressure is valid if you require less force to reset the shooter than to make the shot. Less pressure on the exhaust side will limit the required exhaust flow (less air to move) and increase the velocity of the piston. To change the pressure, you need a pressure regulator.

[Bill_B]

Originally Posted by gpetilli

A flow control valve will do the opposite of what is desired. A flow control valve does not change the final pressure, but changes how fast the air can enter/leave the cylinder and therefor slows down the travel. He is trying to exhaust the air in the cylinder faster. Since we are limited by the diameter of the valve, he is trying to limit the pressure on the exhausting side, and therefor the amount of air that needs to be expelled. To move the piston, you need more pressure on one side than the other, which we do by venting one side - he is trying to start from a more favorable delta pressure.

I know what the OP wanted. I was merely expanding on Matt's post about the flow control valves. Thanks for the explanation.