# Pneumatic Cylinder Pressure

• posted

Hi Guys (and Gals!),

I was wondering if anyone knew the answer to this:

Is the force exerted by two cylinders different depending on where a COMMON air feed line is placed? In pictorial form:

Configuration 1:

Air In ---------[]-----------[]

Configuration 2:

Air In --------- | []-------------------------[]

In the first configuration, the air line feeds one cylinder, which tees off and then feeds another cylinder. In the second configuration, the air line feeds a tee which goes to each cylinder.

Would they exert different effective forces given the air in has the same psi?

Thanks!!

• posted

• posted

While moving, yes. If there are significant air leaks in the "close" cylinder, yes. When the cylinders are not moving and the air is stagnant, no.

David A. Smith

• posted

Essentially no. I've seen config 1 in use but I don't know why it was done that way. It may have been only to save a fitting or a piece of tubing. It kind of had me puzzled for a bit. There may be some short term differences but in the end it doesn't matter.

Walter.

• posted

Dear Walter Driedger:

differences

You can get a primitive form of sequencing out of that arrangement. One cylinder goes most of the way out, while the distant cylinder basically just loads the mechanism.

Most of the time it just saves tubing, and one fitting (if you do it "right").

David A. Smith

• posted

Thanks everyone for all the VERY helpful replies!!

• posted

depends on the velocity, volume, load. and stroke of each cylinder; the size of the line and pressure; and the length of line and the size of the source

a lot of variables -

basically, if the flow rate into the one cylinder with its load causes enough difference in line loss to have a difference in pressure with the other cylinder, and the loads are not different proportionately, it will show. If the flow is low enough so the difference is small, no difference in piston velocity is seen.

imho

• posted

Yes, but in the case I saw the two cylinders were linked to the same scotch yoke and had to move in exact synchronization.

Walter.

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