PE vs PE with FEP liner
PE vs PE with FEP liner
(OP)
Hello everybody,
I am designing a heat exchanger which involves corrosive materials, which excludes any metal as possibilities as materials. I seem to have narrowed it down to PE by comparing polymers with their respective thermal conductivities.
Now I am faced with the choice between High Density Polyethylene or Polyethylene with a FEP liner. The second has slightly thinner wall thickness, but I am not sure of it's thermal properties.
Is there anybody out there that might be able to tell me if the FEP liner is likely to improve PE's properties or the opposite.
Thank you
Domenic
I am designing a heat exchanger which involves corrosive materials, which excludes any metal as possibilities as materials. I seem to have narrowed it down to PE by comparing polymers with their respective thermal conductivities.
Now I am faced with the choice between High Density Polyethylene or Polyethylene with a FEP liner. The second has slightly thinner wall thickness, but I am not sure of it's thermal properties.
Is there anybody out there that might be able to tell me if the FEP liner is likely to improve PE's properties or the opposite.
Thank you
Domenic





RE: PE vs PE with FEP liner
What corrosive materials/temps? I would have thought Titanium tubing would be about the same cost as FEP - much better conductivity, but not as good as copper (or steel for that matter).
Some domestic boilers have secondary heat exchangers made from PPS. (UK)
A bit more info would be helpful.
Cheers
Harry
RE: PE vs PE with FEP liner
You can add fillers to improve conductivity, but you will lose some corrosion resistance.
Can you use a thin PE coating on copper.
Regards
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RE: PE vs PE with FEP liner
Don't forget that PE or PP will need exceptionally good stabilization using a specialty stabilizer package when used in a heat exchanger.
1. High temperature degrades the plastic (the FEP should be way better than PE and PP)
2. The flow of liquid and / or gas extracts the stabilizer
3. The thin walls mean there is no "reservior" of stabilizer to replace that caused by extraction
Does gold plating the metal work? That would be a nice solution.
There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell
RE: PE vs PE with FEP liner
Thanks again
Domenic
RE: PE vs PE with FEP liner
http://www.cshyde.com/tapecat.htm
There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell
RE: PE vs PE with FEP liner
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: PE vs PE with FEP liner
Thank you once again for everybody's help
RE: PE vs PE with FEP liner
Modern car brake pipes are usually coated with PVDF these days, although if fittings have to be immersed not good.
Cheers
Harry
RE: PE vs PE with FEP liner
In the conditions stated, polyethylene on top of copper is less practical since an adhesive is expected to be required to bind the materials. Nowadays (with current technologies), it is questionable whether the appropriate interface is created for long term resistance to water/acid accumulation and subsequent bulge formation.
Regards,
Rodney
For more integrated knowledge on diffusion and corrosion, also take a look at: http://www.composite-agency.com