Air Pressure as a Pipe Reduces

Reducing the volume of a confined gas 50% doubles its Absolute pressure.

Are we reducing the volume for the same amount of air or are we reducing an air line from 1" to 3/4" in an compressed air system?

42 psi

I don't mind when you beat me to it Del del Gato.

I do. Open goal and I was to slow. Dam!

"What would be air pressure in 3/4'' pipe reduced from 1'', air pressure in 1'' is 42 psi."

And the air pressure in a 1/2" or 1/4" or even a 1/8" pipe is the same 42 psi.

If you open the end of the pipe you will have a gray horse of a different color.

The pressure drop in the pipe(s), the flow in cfm and the outlet pressure are all dependent up the lengths of the various sizes of pipe.

What was the question again?

(P1*V1)/T1 = (P2*V2)/T2 for volume read area.

..........which is applicable to adiabatic expansion of an ideal gas.

The pressure in the pipe will be the same, if there is no flow in it. Once things start moving, that's when the fun starts.

Exactly.....the pressure may even reduce..venturi effect an all that...

I just went for the shortest/simplest answer. Brvty s a vrtu

How pressure change if we use water instead of air ?

The pressure in the pipe will be the same, if there is no flow in it. Once things start moving, that's when the fun starts.

What a stupid Blog.....!!

Not enough proper & relevant info as usual.....

What if we fill the pipe with mice? or Custard?

One could even fill it with nuclear waste. The pressure in the pipe will be the same, if there is no flow in it. Once things start moving, that's when the fun starts.

Good cure for insomnia, this one?

I like custard.

OOOh how about Granma's grits.

MMMMM-HMMMMM

It is true in a no flow condition the air pressure would be the same. When the air starts moving, there is a pressure drop due the the frictional losses of the air against the sidewall of the pipe. Typically the smaller the pipe the higher the frictional losses and therefor the lower the pressure as you move downstream. To accurately do these calculations from scratch you need to understand the reynolds number, Bernoulli, etc. (fluid mechanics). In simple piping systems the FLUID POWER DATA BOOK gives pressure drop tables for pipe runs and fittings. In the U.S. any fluid power distributor will give you a copy of this small handbook for free. You can also order it by calling 1800-569-9801.

sounds like a hwk problem..

$1 Bob, The price is right!

Are you suggesting I am trying to sell something cmnky26? This is certainly not the case. I am a plant engineer in an alumina processing facility and do not have any commercial reason for suggesting someone use a trade handbook that I have copies of that were given to me. The reason I suggest this handbook is because it is a simple reference tool that in some cases can take the place of engineering calculations.

I am continually in search of additional resources and reference materials that have been field proven.

No worries, eh?

Is the pressure the same for clean water or dirty water? if so then will the dirty water flow uphill?

that would be a plumbing question - and they will all say the same "hot water on the left and crap cain't creep uphill"

What would be air pressure in 3/4'' pipe reduced from 1'', air pressure in 1'' is 42 psi.

As your question is - it will be 42 psi even if you reduce it to 1/2". As you release " the fun begins" as rightly said above time & time again.

Before you release it you must mention volume in cfm/m3 and the toltal length of the 3/4" pipe you want to run. Upon these information based on p1-p2/L (intitial pressure factor minus final pressure factor divided by length) it is to be calculated what pressure the 3/4" line will result into at the extreme end of the length.

Well put.....