I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

Ignoramus25760 fired this volley in
:
Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

When I first saw your post, I assumed you were asking about how to weld
feet to a tank, and I was going to suggest "saddle straps" instead --
basically large band clamps around the tank, with the feet welded to the
clamps.

But what you have is potentially a bomb. No. Don't use it. Certified
(or certifiable) tanks are not that expensive. Soft tissues are. Hard
body parts more so.

LLoyd

On Wed, 26 Sep 2007 13:56:20 -0000, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus25760 fired this volley in
:
Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

When I first saw your post, I assumed you were asking about how to weld
feet to a tank, and I was going to suggest "saddle straps" instead --
basically large band clamps around the tank, with the feet welded to the
clamps.

But what you have is potentially a bomb. No. Don't use it. Certified
(or certifiable) tanks are not that expensive. Soft tissues are. Hard
body parts more so.

LLoyd

Lloyd, that's exactly my thoughts as well. Thanks a lot. I would never
weld anything to a compressor tank. A 120 gallon tank at, say, 200
PSI, would probably take down more than one home in my neighborhood.

i

Ignoramus25760 wrote:
I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

take it home and use it.

On 26 Sep, 16:40, Cydrome Leader wrote:


take it home and use it.-

I'm glad you don't live near me!

On Wed, 26 Sep 2007 08:37:25 -0500, Ignoramus25760
wrote:

I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

That would be the safe course.

That said, how do you suppose those tanks are made? They're welded! I
have welded on compressed air tanks. No problems. But you don't know
if the guy that did the welding on the tank in question was any good,
or if he tested it after welding. Or, for that matter, that they
used it as a pressure vessel after welding since it was separated from
the pump.

Welds near the bottom can burn the galvanizing off the inside,
creating a site for condensate-caused rusting from inside out.

On Wed, 26 Sep 2007 12:02:17 -0500, Don Foreman wrote:
On Wed, 26 Sep 2007 08:37:25 -0500, Ignoramus25760
wrote:

I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

That would be the safe course.

That said, how do you suppose those tanks are made? They're welded! I
have welded on compressed air tanks. No problems. But you don't know
if the guy that did the welding on the tank in question was any good,
or if he tested it after welding. Or, for that matter, that they
used it as a pressure vessel after welding since it was separated from
the pump.

Welds near the bottom can burn the galvanizing off the inside,
creating a site for condensate-caused rusting from inside out.

Don, I thought that compressor tanks are heat treated after
welding. That would relieve stresses and such. Since you welded
compressed air vessels, maybe you know the answer, I would lova to
know myself.

i

On Sep 26, 1:37 pm, Ignoramus25760 ignoramus25...@NOSPAM.
25760.invalid wrote:
I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

It might be okay. It might not. But it's very hard to know, and it's
unlikely that anyone in this newsgroup will be able to give you a
definite answer. Personally, I would not use the tank.

The danger isn't so much that the tank will fail immediately. The
danger is more that the welds will act as initiation sites for fatigue
cracks, which will grow ever so slightly with each cycle of
pressurisation and de-pressurisation, until eventually the tank fails.
This is a situation in which the quality of the welds is very
important.

I can't think of a major disaster which was caused in exactly this
way, but the Alexander Kielland oil rig disaster was very close. A
bracket for mounting an underwater instrument was welded onto one of
the bracing members of the rig. It was done without the knowledge of
the rig's designer and by all accounts it was done badly. The waves
caused the stress in the bracing member to vary cyclically, and a
crack began to grow. Eventually the bracing member broke during a
storm, allowing one of the platform's legs to break off, and the
platform to capsize.

This isn't the exact explanation of the disaster given in the
Wikipedia article, but it's the explanation given in a book I have on
the disaster, which is probably more trustworthy.

Best wishes,

Chris

Take the tank home and use it.. infact rig it up so you can put about twice
the pressure in that it was designed for. When it blows you have one hell
of a law suit against Fermilab for allowing you to take a defective tank
from their dumb. If they were going to scrap it as unsafe they should have
taken a shotgun or an airhammer to it .
LLB


"Ignoramus25760" wrote in message
...
I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

On Wed, 26 Sep 2007 12:11:06 -0500, Ignoramus25760
wrote:

On Wed, 26 Sep 2007 12:02:17 -0500, Don Foreman wrote:
On Wed, 26 Sep 2007 08:37:25 -0500, Ignoramus25760
wrote:

I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

That would be the safe course.

That said, how do you suppose those tanks are made? They're welded! I
have welded on compressed air tanks. No problems. But you don't know
if the guy that did the welding on the tank in question was any good,
or if he tested it after welding. Or, for that matter, that they
used it as a pressure vessel after welding since it was separated from
the pump.

Welds near the bottom can burn the galvanizing off the inside,
creating a site for condensate-caused rusting from inside out.

Don, I thought that compressor tanks are heat treated after
welding. That would relieve stresses and such. Since you welded
compressed air vessels, maybe you know the answer, I would lova to
know myself.

i

I don't know. Some might be. I knew a boilermaker who made big tanks
out of 5/8" steel plate that he pressure tested to 200 PSI. I'm sure
he didn't heat treat them. These suckers were 8 or 10 feet in
diameter. Tawk about a slip roll! They were stick-welded. Rollers
turned the tank as it was being welded, the welder just held the
stick and watched the puddle. He could probably control the roller
speed, but that probably didn't change once set to his satisfaction.

On Sat, 29 Sep 2007 12:47:36 -0500, Don Foreman
wrote:

On Wed, 26 Sep 2007 12:11:06 -0500, Ignoramus25760
wrote:

On Wed, 26 Sep 2007 12:02:17 -0500, Don Foreman wrote:
On Wed, 26 Sep 2007 08:37:25 -0500, Ignoramus25760
wrote:

I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

That would be the safe course.

That said, how do you suppose those tanks are made? They're welded! I
have welded on compressed air tanks. No problems. But you don't know
if the guy that did the welding on the tank in question was any good,
or if he tested it after welding. Or, for that matter, that they
used it as a pressure vessel after welding since it was separated from
the pump.

Welds near the bottom can burn the galvanizing off the inside,
creating a site for condensate-caused rusting from inside out.

Don, I thought that compressor tanks are heat treated after
welding. That would relieve stresses and such. Since you welded
compressed air vessels, maybe you know the answer, I would lova to
know myself.

i

I don't know. Some might be. I knew a boilermaker who made big tanks
out of 5/8" steel plate that he pressure tested to 200 PSI. I'm sure
he didn't heat treat them. These suckers were 8 or 10 feet in
diameter. Tawk about a slip roll! They were stick-welded. Rollers
turned the tank as it was being welded, the welder just held the
stick and watched the puddle. He could probably control the roller
speed, but that probably didn't change once set to his satisfaction.


Although possible it would seem inefficient to heat treat a pressure
vessel after welding. While a heat treated vessel could be made from
thinner material the additional cost of heat treating would probably
result in a higher manufacturing cost that if simply rolled and welded
from "as delivered" stock. Can you imagine the cost of an oven to take
a 10 ft. diameter vessel? Or the amount of energy necessary to heat
it?


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Sep 26, 5:07 pm, "Gary Owens" wrote:
If you know the person who welded the PV or did it your self, thats one
thing, but to take a unknown 120 gal PV that had been modified and fill it
to 150psi+_ is risking allot. PV's are for the most part not stress
relieved, but they are welded by certified welders (or should have been).
and they are hydro checked. And do you know what was in it ? It may have
been highly corrosive.
gary

"Ignoramus25760" wrote in message

...



I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i- Hide quoted text -

- Show quoted text -


Gary just said it...don't assume that the tank was used for air.

Femi is a R&D site and they use tanks for many things...some of them
very nasty.

Many times the decommisioning of equipment is cough..cough...marginal.

Couple that with the unknown history of the tank and the "Why did they
get rid of it?" factor and I would leave it alone.

I buy almost all my machines used....I buy all my pressure vessels
new.

I consider it money well spent.

FWIW....any compressor, tank, vacuum pump, high pressure line is
suspect and should be dealt with carefully. Semiconductor production
for example uses some very nasty chemicals that never are quite dealt
with before the equipment is salvaged.

If the surplus came from a biological based surplus source like a
hospital or life science lab, you want to be really careful that it
doesn't have some very bad living things waiting for their next host.

TMT

On Sun, 30 Sep 2007 08:38:55 -0700, Too_Many_Tools wrote:
Gary just said it...don't assume that the tank was used for air.

Femi is a R&D site and they use tanks for many things...some of them
very nasty.

Many times the decommisioning of equipment is cough..cough...marginal.

Couple that with the unknown history of the tank and the "Why did they
get rid of it?" factor and I would leave it alone.

I buy almost all my machines used....I buy all my pressure vessels
new.

I consider it money well spent.

FWIW....any compressor, tank, vacuum pump, high pressure line is
suspect and should be dealt with carefully. Semiconductor production
for example uses some very nasty chemicals that never are quite dealt
with before the equipment is salvaged.

If the surplus came from a biological based surplus source like a
hospital or life science lab, you want to be really careful that it
doesn't have some very bad living things waiting for their next host.

TMT


I am 100% positive that it is an air tank from the compressor.

i

On Sep 29, 5:47 pm, Don Foreman wrote:

snip

I don't know. Some might be. I knew a boilermaker who made big tanks
out of 5/8" steel plate that he pressure tested to 200 PSI. I'm sure
he didn't heat treat them. These suckers were 8 or 10 feet in
diameter. Tawk about a slip roll! They were stick-welded. Rollers
turned the tank as it was being welded, the welder just held the
stick and watched the puddle. He could probably control the roller
speed, but that probably didn't change once set to his satisfaction.

Interesting. A while back I was talking to a guy who was welding the
tyres of railway wagon wheels as part of a repair process. He said he
tried welding them by putting the wheelset in a huge lathe and setting
it turning very slowly, but that it was actually not a great deal of
help. He said it was much harder than it looked to lay a bead at
precisely the same speed as the wheel turned, so instead he preferred
to weld a section with the wheel stationary, then rotate the wheel
before continuing. He did an exceptionally neat job too; you couldn't
see the restarts.

Best wishes,

Chris

wrote:
o


Although possible it would seem inefficient to heat treat a pressure
vessel after welding. While a heat treated vessel could be made from
thinner material the additional cost of heat treating would probably
result in a higher manufacturing cost that if simply rolled and welded
from "as delivered" stock. Can you imagine the cost of an oven to take
a 10 ft. diameter vessel? Or the amount of energy necessary to heat
it?


Postweld heat treat for large pressure vessels is done all the time.
It is not done within an oven
unless the vessel is pretty small. What is normally done is wrap the
weld area and the HAZ with
thermal blankets that have electric heating elements in them and the
area is brought up to the
specified temp for the the required time. The largest that I've
personally seen done were some
reactors that my dad was the materials and welding engineer on. They
were 20+ feet in
daimeter and over 200' tall when stood up. Vessel wall thickness was
11". When completed they
were barged out of the US to Trinidad and installed in a refinery
there.

You know you are working with big stuff when someone considers vessel
material under 1"
to be sheet metal!

On Sun, 30 Sep 2007 12:36:20 -0700, Christopher Tidy
wrote:

snip
Interesting. A while back I was talking to a guy who was welding the
tyres of railway wagon wheels as part of a repair process. He said he
tried welding them by putting the wheelset in a huge lathe and setting
it turning very slowly, but that it was actually not a great deal of
help. He said it was much harder than it looked to lay a bead at
precisely the same speed as the wheel turned, so instead he preferred
to weld a section with the wheel stationary, then rotate the wheel
before continuing. He did an exceptionally neat job too; you couldn't
see the restarts.

I've made a few jigs in the past so I could turn stuff by
hand while welding them. It isn't terribly hard to adjust
your speed that way.

One of the problems is that it needs to be pretty smooth
(the turning) or you run the risk of liquid metal (puddle)
running away. A good type of bearing helps a lot with that.
Vibration is no good for the quality of the weld either if
it happens while the puddle is setting up. All of this is
doable, but it takes some planning and practice for it to
work well.

--
Leon Fisk
Grand Rapids MI/Zone 5b
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