[AT] Pressure drop?

[Dudley Rupert]

The following site contains a table that will answer the question (assuming
the table is correct) -

http://www.engineeringtoolbox.com/compressed-air-pressure-loss-d_1014.html

For example, it looks like for a 1/2" pipe with 10 SCFM of air flowing
through it @100PSI the drop is 0.4 psi for every 100 feet of pipe.

Like Dean said in a post a few minutes ago electricity and airflow behave a
lot alike.  Voltage drop is the easier to calculate however.  For example,
if you double the amount current through a wire you simply double the
voltage drop between the ends of the wire (Ohms Law).  From the table above,
however, it looks like air pressure drop in a pipe is more complicated to
compute; that is, it cannot be computed by a simple (linear) expression of a
couple of variables ... maybe with some regression analysis and fancy curve
fitting one could come with a polynomial for computing air pressure drop.

Dudley
Snohomish, Washington


-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com]On Behalf Of
rlgoss at insightbb.com
Sent: Tuesday, January 29, 2008 7:16 PM
To: Antique tractor email discussion group
Subject: Re: [AT] Pressure drop?

It's going to depend on the flow rate, Farmer.  If it's just a pressurized
line, there is no pressure drop.  But if you want it to deliver 9 CFM at 90
PSI, you may have trouble.  I don't have the formula with me for doing the
calculation, but it shouldn't be difficult to find.  Try searching for "line
loss."

Larry


----- Original Message -----
From: Francis Robinson <robinson at svs.net>
Date: Tuesday, January 29, 2008 20:57
Subject: [AT] Pressure drop?
To: Antique tractor email discussion group <at at lists.antique-tractor.com>

> OK, who knows compressed air pressure drop off of the top of
> your head?
> :-)
> I am going to run a compressed air line from one shop to the
> other. It
> will run inside of an underground conduit in 1/2" PEX tubing. It
> will
> basically have one fitting (full 1/2") at each end of the run.
> The run will
> be 250' long with no fittings at all in the line itself. If I
> have 125 PSI
> at one end what kind of drop can I expect at the other end? What
> would it
> be at 800'?
> BTW, PEX is rated and recommended for compressed air. I was
> reading the
> print on the pipe today and for water what I have on hand at the
> moment is
> rated at 100 PSI at 180 degrees F. It will not get hard and
> brittle and it
> will not shatter on impact. It is cross linked polyethylene and
> is not
> affected by oil.
> I am really in love with this stuff for water plumbing.
>
>
>
>
>
> --
> "farmer"
>
>
> Francis Robinson
> Central Indiana, USA
> Robinson at svs.net
> _______________________________________________
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> http://www.antique-tractor.com/mailman/listinfo/at
>

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