laminated glass tubes

"Bernhard Kuemel" wrote in message
.. .
Hi!

I make display glass tubes with high pressure content (up to 200 bar).
To protect the tubes from damage and to protect the spectators from
shrapnel in case of an explosion I try to make a protective cover.

Previously I used polycarbonate tube which is strong enough, but is easy
to scratch and may turn brittle eventually. So I'm looking for something
that will last 100+ years. I try to make laminated glass tubes. Filling
the 1-3mm gap between concentric glass tubes with polyester produced
bubbles as the polyester shrunk when it set.

Can you recommend other materials to fill the gap? They should ...

last very long (100+ years)
excellent optical clarity
The temperature range might be -40 °C (cold weather) to 70 °C (inside a
car in full sun).

Preferably they should be...

tough
low viscosity so I can get them in the gap
index of refraction and thermal expansion similar to borosilicate glass
- 1,52 and 5 * 10^?6
not too expensive

Currently I'm thinking of ...

1) hydrocarbon gel such as in gel candles. It might be fluid enough so
it will not detach from the glass surfaces when its volume grows and
shrinks with varying temperature. But I'm afraid the hydrocarbons might
evaporate.

2) crystal clear polyurethane resin.

3) crystal clear silicone or modified silicone/silane (MS-polymer)

4) Other crystal clear sealants

Actually just a simple (viscous) liquid (glycerol) might do the job, if
it could be sealed in the gap reliably.

Thanks, Bernhard

Why not make samples and test them by breaking them at 200 bar
and seeing what the result is?

Any restriction on thickness (bullet -proof glass)?
Any restriction on wire?
http://www.fireglass.com/glass/wirelite-nt/

Androcles wrote:
"Bernhard Kuemel" wrote in message
.. .
Hi!

I make display glass tubes with high pressure content (up to 200 bar).
To protect the tubes from damage and to protect the spectators from
shrapnel in case of an explosion I try to make a protective cover.

Why not make samples and test them by breaking them at 200 bar
and seeing what the result is?

I do make explosion tests with display tubes filled to higher than
normal pressure. But acquiring the materials costs money and making the
pressure and protective tubes is a lot of work so I try to pick the
ideal materials at first.

Any restriction on thickness (bullet -proof glass)?

Not unless they remain practical. I'm currently thinking of 60 mm total
outer diameter with 7 mm wall thickness for the outer tube, 1-3 mm gap
material and 2 mm inner tube of the protective tube. That's 10-12 mm
total wall thickness of the protective tube. Length is 20-25 cm.

The pressure tube within the protective tube is 10 mm OD.

But I could not find bullet proof glass *tubes*. I did find laminated
glass tubes intended as pillars in building construction. However, they
cost near 100 Euro per 25cm piece.

I thought of using laminated glass panes, which are easier to make. But
a tube looks much better than a cuboid. Also how do I join the panes so
they will not open at the edges when the pressure tube explodes.

Any restriction on wire?
http://www.fireglass.com/glass/wirelite-nt/

The purpose is to watch the pressure tube in detail. So I will try
without wires.

Bernhard

"Bernhard Kuemel" wrote in message
.. .
Androcles wrote:
"Bernhard Kuemel" wrote in message
.. .
Hi!

I make display glass tubes with high pressure content (up to 200 bar).
To protect the tubes from damage and to protect the spectators from
shrapnel in case of an explosion I try to make a protective cover.

Why not make samples and test them by breaking them at 200 bar
and seeing what the result is?

I do make explosion tests with display tubes filled to higher than
normal pressure. But acquiring the materials costs money and making the
pressure and protective tubes is a lot of work so I try to pick the
ideal materials at first.

Any restriction on thickness (bullet -proof glass)?

Not unless they remain practical. I'm currently thinking of 60 mm total
outer diameter with 7 mm wall thickness for the outer tube, 1-3 mm gap
material and 2 mm inner tube of the protective tube. That's 10-12 mm
total wall thickness of the protective tube. Length is 20-25 cm.

The pressure tube within the protective tube is 10 mm OD.

But I could not find bullet proof glass *tubes*. I did find laminated
glass tubes intended as pillars in building construction. However, they
cost near 100 Euro per 25cm piece.

I thought of using laminated glass panes, which are easier to make. But
a tube looks much better than a cuboid. Also how do I join the panes so
they will not open at the edges when the pressure tube explodes.

Any restriction on wire?
http://www.fireglass.com/glass/wirelite-nt/

The purpose is to watch the pressure tube in detail. So I will try
without wires.

Bernhard
If you use a thick-wall tube of toughened glass then why would
you need a protective tube at all? Seems to me you are making
hard work for yourself taking a precaution that is excessive, but
then I don't know what your costs are. Have you approached
any glass manufacturers and obtained quotes?
http://tinyurl.com/y9442wu

Bernhard Kuemel wrote:

I thought of using laminated glass panes, which are easier to make. But
a tube looks much better than a cuboid. Also how do I join the panes so
they will not open at the edges when the pressure tube explodes.

What about a box that is metal on all sides
but one, the latter being the laminated plate
glass?

Or maybe metal on all sides with a video
camera and lamp inside with the tube.

Mark Thorson wrote:

Bernhard Kuemel wrote:

I thought of using laminated glass panes, which are easier to make. But
a tube looks much better than a cuboid. Also how do I join the panes so
they will not open at the edges when the pressure tube explodes.

What about a box that is metal on all sides
but one, the latter being the laminated plate
glass?

Or maybe metal on all sides with a video
camera and lamp inside with the tube.

The cute part is seeing critical point opalescence for CO2, N2O, SF6,
CF3Br, propane, CCl2F2, CH2F2, ethylene, C2F6, etc. Gotta have a
through-sight path.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz4.htm

Uncle Al wrote:

The cute part is seeing critical point opalescence for CO2, N2O, SF6,
CF3Br, propane, CCl2F2, CH2F2, ethylene, C2F6, etc. Gotta have a
through-sight path.


What aren the hazards?
Glass shards of explosion,
Expanding gas volume?
some materials are volatile?

You apparently want to warm up and cool in mionutes.
That is lot of stress on any glass.

Shards can be conteiined between laminated windows
Escapinh gas needs a safe path out
Fire hazard must be in control.

For heating and cooling it is better to have the protective
windows at some distance so they do not increase the thermal mass.

observer || U || light source
where || are flat laminated windows, U is the test vial.
-lauri

Lauri Levanto wrote:

Uncle Al wrote:

The cute part is seeing critical point opalescence for CO2, N2O, SF6,
CF3Br, propane, CCl2F2, CH2F2, ethylene, C2F6, etc. Gotta have a
through-sight path.


What aren the hazards?
Glass shards of explosion,
Expanding gas volume?
some materials are volatile?

You apparently want to warm up and cool in mionutes.
That is lot of stress on any glass.

Shards can be conteiined between laminated windows
Escapinh gas needs a safe path out
Fire hazard must be in control.

For heating and cooling it is better to have the protective
windows at some distance so they do not increase the thermal mass.

observer || U || light source
where || are flat laminated windows, U is the test vial.
-lauri

The hazard is not the thick wall glass tube. The hazard is surface
damage allowing the glass to fail in tension. A wafer of boron
carbide can have a razor edge. Stroke it across a glass tube normal
to the long axis. the imperceptable scratch, when flexed scratch
outward, parts the tube as though it were never one piece.

Coat the glass with polymer so the glass is not at the surface.
Mistreatment will still burst the tube. A inch of weatherized
polycarbonate will contain any shrapnel, but its large refractice
index plus low Abbe number distorts and colors the image. The modern
solution is to have a competent tube behind a barrier, a 45-degree
mirror, and usually a videocam.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz4.htm

Uncle Al wrote:

Mark Thorson wrote:

What about a box that is metal on all sides
but one, the latter being the laminated plate
glass?

Or maybe metal on all sides with a video
camera and lamp inside with the tube.

The cute part is seeing critical point opalescence for CO2, N2O, SF6,
CF3Br, propane, CCl2F2, CH2F2, ethylene, C2F6, etc. Gotta have a
through-sight path.

Why do people use CO2? Wouldn't one of those
other molecules be a lot safer? What would be
the safest candidate?

Mark Thorson wrote:
Uncle Al wrote:
Mark Thorson wrote:
What about a box that is metal on all sides
but one, the latter being the laminated plate
glass?

Or maybe metal on all sides with a video
camera and lamp inside with the tube.
The cute part is seeing critical point opalescence for CO2, N2O, SF6,
CF3Br, propane, CCl2F2, CH2F2, ethylene, C2F6, etc. Gotta have a
through-sight path.

Why do people use CO2? Wouldn't one of those
other molecules be a lot safer? What would be
the safest candidate?

CO2 is cheap and available. It has an excellent critical temperature.
You can make it critical with body heat or other low power heating and
cool it below critical with ambient temperature. It is non toxic, non
ozone depleting (influences availability). Its (super)critical pressure
is low enough so it can be contained in glass tubes.

CClF3 has great critical data (29°C, 39 bar), but it is ozone depleting
and hard to get. C2F6 has even lower pc (33 bar), but Tc is silghtly too
low (19 °C) so it would have to be cooled to go subcritical. It's
expensive (compared to CO2) and I would have to buy or rent a pressure
bottle. And even at 33 bar (or more if supercritical) a protective case
is very preferable. So I just use CO2. Supercritical CO2 is also used
industrially and so is particularly interesting for people to watch.

Ohh, BTW, Helium would be the safest candidate: 2.3 bar, but at 5 K.
Or something like C7F16 with 16 bar and 202 °C in an oil bath might be
an option.

Bernhard

On Sun, 27 Dec 2009 12:39:00 -0800 (PST), iman way wrote:
I am happy to be a member of this group and I consider you my friends.
As a friend , I like to share with you some thoughts that I believe
will be useful for your life.

With friends like that, who needs Dennis?