Parallel or Series, which is better?

[diesel]

Our team is having trouble deciding which is better.
The strengths and weaknesses of each would be great. (And reasonings for them are also a bonus!) Thanks in advance.

[AdamHeard]

in reference to what?

[whytheheckme]

Hah. I saw the title of this thread, and was like.....

Parallel and Serial ports???

Then I saw it was under pneumatics.

Yes, please provide some more information as to the system you are referring to. Always keep in mind the pneumatic guide posted on the FIRST website.

Jacob

[Sunshine]

We need a little more info.......

What are you putting in series or parallel?
batteries?
loads? (resistance?)

I'll take a guess of what you are asking.........

When connecting two batteries in series you are doubling the voltage while maintaining the same capacity rating.

When connecting 2 batteries in parallel you are doubling the capacity (amp hours) of the battery while maintaining the voltage of one of the individual batteries

[mrbob1000]

i think they mean pneumatic tanks and/or pistons.

if you put the tanks in series or parallel doesn't matter.

if you put pistons in parallel then yo get the same pressure on both calenders.

[1086VEX]

from my experience it doesnt matter if your pneumatics system is in seris or parallel...

[ALIBI]

When charging the tanks it would not matter. You will be restricted by the tubing. Discharging the tanks may be a different story. If you wanted to fire four cylinders at the same time as fast as possible, would it make sence to have the tanks in parallel? It seems as though if you feed four valve/cylinder combinations through four pieces of tubing with each one connected to a different tank verses a single piece of tubing feeding air through a single valve teed to four cylinders that the volume of air would be less resticted. Has anyone ever tried this? The amount of brass, valves and regulators of doing this would take a large piece out of your weight budget. I am not sure if this type of setup is legal. It is just an idea at this time.

[diesel]

Sorry for not being clear.

Yes, I am talking about pnuematic tanks.
We have one piston on our robot.
Will putting the tanks in parallel provide more force?
Will putting them in series make the pressure last longer?
And any other facts would be great.

Thanks.

[MrForbes]

The air from the tanks all has to go through one regulator, so it really does not matter how you connect the tanks....things will be moving slowly if the cylinder is large diameter.

[Gary Dillard]

Originally Posted by diesel

Sorry for not being clear.

Yes, I am talking about pnuematic tanks.
We have one piston on our robot.
Will putting the tanks in parallel provide more force?
Will putting them in series make the pressure last longer?
And any other facts would be great.

Thanks.

1) Putting the tanks in parallel does not provide more force. Force in your piston is generated by the area of the piston times the pressure downstream of the regulator, which is the lesser of the regulator setting (60 psi default, lower if you dial it down or use a second regulator) or the pressure in the tanks (when the regulator no longer has to "regulate" a higher pressure down to its setting). The pressure is the same in both tanks (and all the tubing up to the regulator) regardless of whether it is a series or parallel connection because it is really just one big volume of air connected by tubing. Since you are drawing air out of this volume through the same size tubing, the remaining air is able to stabilize/equalize to the same pressure regardless of where you remove air from the storage volume.

2) By similar reasoning, the pressure will last the same amount of time for series and parallel, because you are storing the same volume of air either way, and removing the air at the same rate either way.

[David Brinza]

Speaking of parallel:

Is it legal to use two regulators in parallel to provide 60 psi to pistons from the 120 psi tanks? Twice the flow would be available...

[Mr. Freeman]

Originally Posted by David Brinza

Speaking of parallel:

Is it legal to use two regulators in parallel to provide 60 psi to pistons from the 120 psi tanks? Twice the flow would be available...

I thought about doing that on our robot, but I don't think it's legal.

<R98> “Working” air pressure on the ROBOT must be no greater than 60psi. All working air must
be provided through the Norgen adjustable pressure regulator, and all other pneumatic
components must be downstream from this regulator. A pressure gauge must be placed
adjacent to the pressure regulator and display the downstream pressure.

[Daniel_LaFleur]

Originally Posted by diesel

Sorry for not being clear.

Yes, I am talking about pnuematic tanks.
We have one piston on our robot.
Will putting the tanks in parallel provide more force?
Will putting them in series make the pressure last longer?
And any other facts would be great.

Thanks.

OK, the simple answer is ... it depends.

It depends on what is the controlling orifice (what has the most restriction or lowest CV) as to whether series or parallel is better. squirrels' answer assumes that the regulator is the controlling orifice, which is generally not true. Usually the valve has the controlling orifice.

Changing the path at the controlling orifice (IE splitting the flow path and having it run through 2 valves) will garner you the biggest bang for the buck.

Originally Posted by David Brinza

Speaking of parallel:

Is it legal to use two regulators in parallel to provide 60 psi to pistons from the 120 psi tanks? Twice the flow would be available...

I believe that the regulators are a 'bleed' type which means that when the output overpressurizes (goes over the setpoint pressure of the diaphram) the regulator bleeds off the excess pressure through a pressure relief vent. This would mean that if both regulators weren't set EXACTLY at the same pressure (no easy feat) then one would continue to supply air while the other would be venting it, and that would tax your on-board compressor.

[Gary Dillard]

Originally Posted by Daniel_LaFleur

OK, the simple answer is ... it depends.

It depends on what is the controlling orifice (what has the most restriction or lowest CV) as to whether series or parallel is better. squirrels' answer assumes that the regulator is the controlling orifice, which is generally not true. Usually the valve has the controlling orifice.

We're splitting hairs here, but in reference to his question - should the tanks be in series or in parallel, the fact that the valve is the controlling orifice has nothing to do with the answer to that question. By the rules, all the flow from the tanks has to go through a single tube into a single regulator and then out to the system. Regardless of whether you put one valve or 10 valves downstream, the rate at which air will go through that one tube and one regulator is not dependant on whether the tanks are in series or parallel. The storage volume will discharge at the same rate.

[Los Frijoles]

All that tanks really are is very large diameter tubing. Since Air is a gas, it will flow freely to fill up the entire space that it is given, so placement of the tanks does not have a serious effect on the way the air flows. Only in applications where the movement of air is critical and at high velocity like pneumatic potato guns does tank placement matter.