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making laminated glass tubes



 
 
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  #1  
Old March 18th 09, 09:42 AM posted to rec.crafts.glass,sci.chem
Bernhard Kuemel
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Posts: 7
Default making laminated glass tubes

Hi!

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes. Currently I put it in a
protective polycarbonate tube, but I'm worried the PC might not last
long enough. Some of the tubes might be in use for 100+ years. They are
meant to be viewed by students/pupils in schools and universities. There
will probably be little UV exposure, but some tubes may be on display
permanently, though still inside.

So ... what would be the best material to fill the gap between 2
concentric glass tubes? Polyester, Epoxide, PU, Polycarbonate,
Polyvinylbutyral, ...? It should be managable with low tech equipment.

How opaque is (borosilicate) glass to UV?

Thanks, Bernhard
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  #2  
Old March 18th 09, 10:26 AM posted to rec.crafts.glass,sci.chem
Bernhard Kuemel
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Posts: 7
Default making laminated glass tubes

Bernhard Kuemel wrote:
So ... what would be the best material to fill the gap between 2
concentric glass tubes? Polyester, Epoxide, PU, Polycarbonate,
Polyvinylbutyral, ...? It should be managable with low tech equipment.


Actually I first thought of filling the gap with a viscous liquid like
glycerol or silicone oil.

A test explosion of a 1 cm OD pressure tube shattered a 60mm OD
borosilicate glass tube with 7mm wall to rather large pieces. I think,
if the outer tube were not struck by the glass fragments of the pressure
tube, the protective glass tube will withstand the shock wave. The
pressure in the pressure tube (10mm OD, 5.5mm ID) may exceed 200bar. It
was up to 240 bar without breaking.

With a laminated glass tube, is there a possibility that the glass will
crack from thermal expansion of the resin layer? The resin also should
not separate from the glass as this would create additional optical
surfaces which decrease optical transparency.

Bernhard
  #3  
Old March 23rd 09, 07:55 AM posted to rec.crafts.glass,sci.chem
Richard J Kinch
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Posts: 4
Default making laminated glass tubes

Bernhard Kuemel writes:

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes.


Really, in glass? What is the application?

"Double bagging" seems a fool's errand. Things just cascade until the
energy is absorbed. You must disperse the energy, such as through a
stainless mesh.
  #4  
Old March 23rd 09, 11:30 PM posted to rec.crafts.glass,sci.chem
SoundChaser
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Posts: 1
Default making laminated glass tubes

"Richard J Kinch" wrote in message
. ..
Bernhard Kuemel writes:

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes.


Really, in glass? What is the application?

"Double bagging" seems a fool's errand. Things just cascade until the
energy is absorbed. You must disperse the energy, such as through a
stainless mesh.



I'm a pretty adventurous soul, but I wouldn't keep those tubes anywhere
near me....

  #5  
Old March 24th 09, 03:54 AM posted to rec.crafts.glass,sci.chem
Salmon Egg
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Default making laminated glass tubes

In article ,
"SoundChaser" wrote:

"Richard J Kinch" wrote in message
. ..
Bernhard Kuemel writes:

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes.


Really, in glass? What is the application?

"Double bagging" seems a fool's errand. Things just cascade until the
energy is absorbed. You must disperse the energy, such as through a
stainless mesh.



I'm a pretty adventurous soul, but I wouldn't keep those tubes anywhere
near me....


In the British Science Museum located in London, there is an exhibit
using liquid carbon dioxide in a glass tube. It is used to demonstrate
what happens when the triple point temperature is exceeded. As the tube
is heated, the interface between liquid and gas becomes invisible.

AFAIK that may have been around for over a hundred years. Why not find
out what they do and how they protect the public?

Bill

--
Private Profit; Public Poop! Avoid collateral windfall!
  #6  
Old March 24th 09, 06:29 PM posted to rec.crafts.glass,sci.chem
[email protected]
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Posts: 3
Default making laminated glass tubes

On Mar 18, 1:42*am, Bernhard Kuemel wrote:
Hi!

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes.


1. Substitute another liquid and tell the customers it's CO2. It can
even be a fluorocarbon that will demonstrate the triple point, but at
a lower pressure.

2. Use concentric PC tubes and test, test, test. (But visibility will
be reduced.)

3. Embed in solid transparent polymer and provide a pressure relief at
one end.

4. Use pressure rated steam boiler sight tubes and pass on the
liability to the manufacturer.

5. Buy lots of liability insurance.

DB
  #7  
Old March 24th 09, 07:15 PM posted to rec.crafts.glass,sci.chem
Bernhard Kuemel
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Posts: 7
Default making laminated glass tubes

Richard J Kinch wrote:
Bernhard Kuemel writes:

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes.


Really, in glass? What is the application?


To demonstrate the critical point. There's an image of one on
http://de.wikipedia.org/wiki/Kritisc...(Thermodynamik) .

"Double bagging" seems a fool's errand. Things just cascade until the
energy is absorbed.


The technology is applied in e.g. car windows.

You must disperse the energy,


I believe, a glass tube can take the pressure of the CO2 shock wave.
Only the splinters that hit the tube make it break, and the pressure
then drives the splinters away. But liquid or resin layer between 2
concentric glass tubes will prevent splinters hitting the outer glass
tube and disperse the impact pressure evenly.

Maybe it doesn't actually matter much, what middle layer I use. But if
the device breaks from external force a simple (viscous) liquid filler
would not hold the pieces together and then it might be dangerous if the
pressure tube exploded.

such as through a stainless mesh.


The protective tube shall be completely clear to allow good vision of
the critical point events.

Bernhard
  #8  
Old March 24th 09, 07:32 PM posted to rec.crafts.glass,sci.chem
Bernhard Kuemel
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Posts: 7
Default making laminated glass tubes

wrote:
On Mar 18, 1:42 am, Bernhard Kuemel wrote:
Hi!

I have glass tubes filled with liquid CO2 at high pressure and need to
make it safe in case the tube explodes.


1. Substitute another liquid and tell the customers it's CO2. It can
even be a fluorocarbon that will demonstrate the triple point, but at
a lower pressure.


Thought of that. C2F6 has a slightly to low Tc. CFCl3 is unavailable
because it's destroys the ozone layer. And both are much more expensive
than CO2 and prossibly more difficult to handle.

2. Use concentric PC tubes and test, test, test. (But visibility will
be reduced.)


One PC tube would suffice, but it might fail if it degrades by age or UV.

3. Embed in solid transparent polymer and provide a pressure relief at
one end.


Good idea, I thought at first. But that would make heating/cooling the
pressure tube difficult.

4. Use pressure rated steam boiler sight tubes and pass on the
liability to the manufacturer.


Hmm, if they are suitable and available at reasonable cost, that might
be it. I've seen laminated glass tubes as structural elements for
buildings, but they'd charge me around 100 EUR for 25cm pieces.

5. Buy lots of liability insurance.


I want to earn money, not pay. And the insurance probably would try not
to pay if they could blame me. Also I want to avoid accidents.

Thanks, Bernhard
  #9  
Old March 24th 09, 07:34 PM posted to rec.crafts.glass,sci.chem
Bernhard Kuemel
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Posts: 7
Default making laminated glass tubes

Bernhard Kuemel wrote:
Thought of that. C2F6 has a slightly to low Tc. CFCl3 is unavailable


s/to/too. s/CFCl3/CClF3
  #10  
Old March 25th 09, 10:25 PM posted to rec.crafts.glass,sci.chem
[email protected]
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Posts: 3
Default making laminated glass tubes

On Mar 24, 11:32*am, Bernhard Kuemel wrote:
I want to earn money, not pay. And the insurance probably would try not
to pay if they could blame me. Also I want to avoid accidents.


Sounds like you need to do some experiments. The pressure above liquid
CO2 at room temp is about 850 psi, so if you had a tank of air or
nitrogen at 2000 psi, you can pressurize the tubes until they explode,
or don't.

If they can take 2000 psi, good, but then you'll have to test for
shock resistance, if only to cause the glass to fracture. This will
test the ability of the PC shell to hold in the explosion.

Finally, you have to get some information from the PC maker on long
term performance of their products. Atlas Material Testing Co, of
Chicago, IL, may be able to point you in the right direction. That's
what they do for a living.

Dangerous Bill

 




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