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Strong and insulation material
3

Strong and insulation material

Strong and insulation material

(OP)
Hi there,

We are designing the support structure of a chamber working at -25ºC. This chamber is like 700 kg and can be held only from one side (around 800 mm diameter)

In order to support it, we need some mechanical parts both very strong and thermally insulating.

We were thinking about glass fiber reinfored with epoxi, but we are not experts in these kind of materials

Does anyone have any other suggestion?

thank you
regards

RE: Strong and insulation material

(OP)
The idea right now is using cylinders of 20-30 mm in diameter and 100 mm in length

About the insulation, nothing is decided; we just want not having water in the warm side (temperature above the dew point). One first guess is below 1 W/mºK

cheers,

RE: Strong and insulation material

(OP)
= 0.5779 Btu/(ft.hr.ºF)

RE: Strong and insulation material

(OP)
When you mentioned in the last post about using metals I checked and saw the titanium. It is not so high but higher than we expect. The problem is not the thermal loss but the temperature in the warm side

cheers,

RE: Strong and insulation material

You already mention dew point. At temperatures below the dew point you must use a non-porous or sealed insulation to prevent it becoming saturated with water. Foamed glass is often used for cryogenic applications, and it can have a fairly high compressive strength.
http://www.foamglas.com/

RE: Strong and insulation material

How about insulation sheet that's used for injection mould tools? High compressive strength, not too expensive, ex stock, down to .17W/mK. Supplied by many but here is an example:

Link

www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

RE: Strong and insulation material

Some ceramics are poor thermal conductors and are very strong in compression. With some creative design you can keep the ceramic in compression while the overall design is in tension - think of overhead line insulator strings, for example.

RE: Strong and insulation material

(OP)
Compositepro,

A foam won't be strong enough

I think we need to use glass fiber, the question is, reinforced with what?

thanks

RE: Strong and insulation material

drodrig,

I believe the material you are looking for is G-10, glass reinforced epoxy. It is easily available in thick plate and extruded shapes and is exceptionally strong and thermally stable within its limits. It is commonly used for structural support in high voltage and transformer applications. The other common application is circuit boards. Another material to consider is phenolic which is available with paper or linen reinforcement. All are very poor thermal conductors.

Timelord

RE: Strong and insulation material

"The problem is not the thermal loss but the temperature in the warm side"

They are related, are they not, by σ * ΔT ?

Note that titanium will typically have higher strength than most G10 formulations, so the smaller volume of material may balance out the deficit in thermal conductivity.

alternately, you could consider either a kevlar or carbon epoxy

TTFN
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RE: Strong and insulation material

(OP)
Hi again,

This G10 looks promising;

Also kevlar, interesting properties.

*About
"The problem is not the thermal loss but the temperature in the warm side"

They are related, are they not, by σ * ΔT ?


They are related. The point is we can live with a few Watts (or hundreds of mW) entering the system, but if the warms side is below the dew point we will get water, which is something we don't want

Thank you all!


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