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
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
According to this 220C is well within its stability limits.
http://www.fluoroprecision.co.uk/temperature-resis...
While Wikipedia has more detailed information saying degradation does start at lower temperatures.
http://en.wikipedia.org/wiki/PTFE
Chris DeArmitt - PhD FRSC CChem
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RE: Breathing device
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
RE: Breathing device
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