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Breathing device

Breathing device

Breathing device

(OP)
Hi all,

I'm building a prototype of a small medical-grade air processor. The air is treated in a number of steps one of which entails heating it up to 220°C. A heating element (mounted in a ceramic socket) has to be placed in a sort of a functional handle required to thermally isolate (as it may be manipulated with at times; this is not crucial as the device may be left to cool-down if needed). The handle is required to hold shape (dynamic deformation of up to 5% is acceptable), but it must also remain absolutely stable thermochemically as this is a breathing device!

I have very limited knowledge of the materials on the market today but it seems that PTFE is popular amongst similar applications. I’m a little concerned with its toxicity though, considering that the required temperature is quite near its rated maximum for thermochemical stability. I have also considered mullite, corundum, or similar "ceramics" but the workability becomes an issue.

Sorry for such a long post (my first one here) to ask a relatively simple question, but I’ve searched the forums and haven’t found what I’m looking for.

Do you consider PTFE to be absolutely safe under the aforementioned circumstances or would you recommend a different material suitable for this prototype?

Thank you in advance!
PL

RE: Breathing device

I think about 400C is where PURE PTFE starts to degrade and maybe out gas. It does degrade and out gas the gas will contain hydrogen fluoride which is very toxic, however this is unlikely in your situation. It is used extensively in cookware with no problems so there is some precedent and there should be plenty of data from the likes of DuPont.

Of course additive to any plastic might alter things considerably to what you get from the pure barefoot resin.

Regards
Pat
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RE: Breathing device

You can use thermoset phenolic material. Additional postcured can handle 220 degC with no problem. It is also V0 by nature. Othervise quite expensive thermoplastics must be used.

RE: Breathing device

I would go for PAI - at least it's injection mouldable (sort of)...

PAI

H

www.tynevalleyplastics.co.uk

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

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