Subject: Re: Air Compressor Safety

From: [email-masked] (Clhuprich)
Date: 12 Jun 1996 15:08:28 -0400

In general these tanks have a coating on the inside to resist rust --
you
may wish to inspect the inside of yours.

Cliff Huprich

---

From: [email-masked] (Blake Malkamaki)
Date: Wed, 12 Jun 1996 00:58:39 -0400

In article <[email-masked]>, [email-masked]
(Mr J Brennan) wrote:

}Hi,
}I was wondering if anyone could confirm a suspicion I have about
}leaving air compressors for extended periods full. I have feeling
}that it is not reccommended because of accelerated corrosion due
}to increased partial pressures of Oxygen - can someone give me an
}idea if this is the case, and if so is it a major safety risk or
}not. I don't have a fixed power supply to my compressor and tend to
}leave it full to charge up tyres etc.
}
}Thanks John
}
}-- 
}John Brennan            Tel +44 1203 523973
}University of Warwick,  Fax +44 1203 524144                     
}Coventry, CV4 7AL,UK    Email [email-masked]       
} 

I feel that with most compressors there is enough oil leakage by the rings
that it tend to coat the inside of the tank with a mist of oil.  There is
also considerable water that condenses inside the tank and goes to the
bottom.  I think the condensation would be more of a concern for corrosion
than the oxygen in the air.
Blake Malkamaki, Little Mountain Ironworks, Concord, Ohio <[email-masked]>
>>Steam engines - Cletrac Crawler Tractors - Maple Syrup - Metal Signs<<
http://www.ncweb.com/users/blake

---

From: [email-masked] (Mr J Brennan)
Date: 11 Jun 1996 23:17:20 +0100

Hi,
I was wondering if anyone could confirm a suspicion I have about
leaving air compressors for extended periods full. I have feeling
that it is not reccommended because of accelerated corrosion due
to increased partial pressures of Oxygen - can someone give me an
idea if this is the case, and if so is it a major safety risk or
not. I don't have a fixed power supply to my compressor and tend to
leave it full to charge up tyres etc.

Thanks John

-- 
John Brennan		Tel +44 1203 523973
University of Warwick,	Fax +44 1203 524144			
Coventry, CV4 7AL,UK	Email [email-masked]

---

From: [email-masked] (James K. Levie)
Date: Wed, 12 Jun 1996 17:59:08 GMT

>leave it full to charge up tyres etc.
While I have no "scientific evidence" as back up, I intuitively feel that,
at the pressures involved, there isn't any significant acceleration of the
corrosion process. Most, if not all, commercial and industrial installations
have hard-wired power to the compressor and the units are on 24x7. As far as
I know there aren't any special precautions taken concerning accelerated
corrosion.

=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
 Jim Levie                                      email: [email-masked]
 The opinions expressed above are just that...  Ph:    (205) 534-1087

---

From: [email-masked] (Jim Naylor)
Date: Thu, 13 Jun 1996 00:30:04 -0600

> may wish to inspect the inside of yours.

Umm, Cliff--I'm having a little trouble getting the light down inside
there. Got any hints please?

-- 
Jim Naylor                             [email-masked]
Wichita KS

---

From: Mike Rehmus <[email-masked]>
Date: 13 Jun 1996 22:19:20 GMT

Probably not a major safety issue.

Commercial applications have air compressors
in operation and the tanks under pressure
for years at a time.

Also, consider the really high pressure air
applications . . . diving tanks, submarine
air storage, Oxygen cylinders, etc.  They
do not seem to have much of a problem in
this regard.

I would drain the tank of any moisture after
each run of the compressor, however.

Best regards,

Mike Rehmus

---

From: [email-masked] (J. Kimberlin)
Date: 14 Jun 1996 17:07:16 -0700

In article <[email-masked]>,
>there. Got any hints please?

If you are really serious about inspecting the inside of your tank, pull 
out the water drain cock and use a bore-scope to look around in there.

JerryK

---

From: [email-masked] (Jim Naylor)
Date: Sat, 15 Jun 1996 10:17:55 -0600

> out the water drain cock and use a bore-scope to look around in there.
Thanks Jerry, but my tongue was firmly planted, cheekwise. Not being the
proud owner of a bore scope or any other suitable optical device (nor
knowing anyone to mooch, er borrow one from), I simply rely on keeping it
well drained, with emphasis on *often*. Before I ever hooked it up, I
replaced the drain plug with an easy to reach valve.

---

From: [email-masked] (Peter Brooks)
Date: 17 Jun 1996 14:26:59 GMT

James K. Levie ([email-masked]) wrote:
: >
: While I have no "scientific evidence" as back up, I intuitively feel that,
: at the pressures involved, there isn't any significant acceleration of the
: corrosion process. Most, if not all, commercial and industrial installations

Hmm, remind me not to visit your garage.....

I live in the south SF bay area, and while not as dry as, say, Phoenix, it's
not all that damp.  Still, after a hard day's run, there's a *bunch* of
water that comes out of my tank when I drain it.  

I don't know if the pressure of O2 would increase corrosion, but oxegenated
water's alway's done a fine job for me.  Short of a dry air intake, I'd drain
the tank daily and if I had any distribution pipes, I'd either put a water
trap in, or drain them daily, too.  12 gallons of air tank at 125 PSI makes
for a respectable bomb, in my book.

Pete Brooks

---

From: [email-masked] (Jim Naylor)
Date: Mon, 17 Jun 1996 12:14:50 -0600

In article <[email-masked]>, [email-masked]
(Clhuprich) wrote:

> In article <[email-masked]>, [email-masked]
> (Jim Naylor) writes:
> 
> Jim,
>     You should be able to remove a pipe fitting from the tank and insert
> a small inspection mirror. Using a pen sized flashlight with the
> inspection
> mirror in a dark room should allow you to inspect the interior of the
> tank.

Thanks Cliff. Sorry I forgot to put the wink in my response.   ;) 

It was a tongue-in-cheek wisecrack, but now that I've thought about it a
little, I wonder what I could tell from the inspection. Even if I saw some
rust or scale (remember, the context is safety), what would that tell me?
Even if there were massive amounts of scale visible, would there really be
a safety concern? Picture putting the plug back in and starting up the
compressor on a rust perforated tank. As the pressure slowly rises and
failure occurs, wouldn't it just result in an increasingly loud hissing
sound as the pinhole enlarges under pressure, forming a self produced
relief opening?

I have two compressors--one a 5 hp on 80 gal vertical tank I use for
sandblasting, etc. I installed an easy to reach valve in its drain before
I ever pressurized it for the first time. Needless to say, I drain it
often. The other one is a 3/4 horse Sears on a portable 15 gal? horizontal
tank with the drain plug in the center of the end bulge (not easy to
drain). It has rusted through repeatedly, but I just braze it up and go on
using it. Methinks that even if a *catastrophic* failure occurred, the
worst that would happen would be a patch of thin rusted metal held
together mostly by paint and brass would be thrown down to the driveway
(or more likely just folded over) with a sound not unlike
quick-disconnecting the hose from the tank. Am I totally naive about this?
Courting disaster? In danger of launching my whole rig down my neighbor's
chimney? Ideas and opinions are welcome, but there's no hurry, I brazed
the first hole over twelve years ago.