Subject: Pipe for air tank?

From: [email-masked] (Bob Neidorff)
Date: Sun, 28 Apr 1996 02:43:02 GMT

What do you think of the idea of using a long 4" or 6" diameter
steel pipe as an air tank?  I was even thinking of an old lolly
column or something.  You could weld a plate on the ends, or even
better, thread the ends and screw on caps, then seal the caps with
a weld bead.  This can't be an original thought.  There must be a
major problem with this.

Come to think of it, what is so special about commercial air 
tanks, other than the fact that they are pressure tested?
--
Bob Neidorff; Unitrode Corporation  |  Internet: [email-masked]
7 Continental Blvd.                 |  Voice   : (US) 603-429-8541
Merrimack, NH  03054-0399 USA       |  FAX     : (US) 603-429-8564

---

From: Andrew Mawson <[email-masked]>
Date: Sun, 28 Apr 1996 14:07:02 +0100

In article <[email-masked]>, Bob Neidorff <[email-masked]>
writes
>tanks, other than the fact that they are pressure tested?
Bob,

The tank on my compressor was far too small, but by connecting a long
length of underground poly water service pipe to feed my foundry at the
bottom of my garden with compressed air all was solved ! I've calculated
that the volume of the pipe is almost as much again as the tank.
Andrew Mawson ------> [email-masked]
Bromley, Kent, UK 0181-466-5582

<-------------Happiness is a fully ticked off list------------->

---

From: [email-masked] (Roger Mitchell)
Date: 29 Apr 1996 18:01:50 GMT

Bob Neidorff ([email-masked]) wrote:
: What do you think of the idea of using a long 4" or 6" diameter
: steel pipe as an air tank?  

In making any pressure vessel always hydrostatic test it before using it.
Hydrostatic testing is no big mystery, just fill the container completely 
full of liquid, attach a gauge and hand hydraulic pump and apply at least
1.5 times the operating pressure. If it is going to fail. it will only spurt
a little liquid rather than spreading shrapnel all over the place. Water is
the most common liquid to test with, though oil has been known to be used in
certain applications also. When filling the container, it must be completely
full with no air space inside. Sometimes the test can be done without a
pump by heating the container after filling it with a small torch to 
increase the pressure by expanding the liquid thermaly. Care needs to be
used however so you don't get too carried away with the pressure as when
doing this the pressure can increase rapidly.
				
				Roger Mitchell
				VP and Master Mechanic
				Fort Collins Municipal Railway
				Fort Collins, Colorado