Non-Metallic Baffles

[htman]

Has anyone used non-metallic baffles on a heat exchanger before? Exchanger is a 14" dia. x 228" lg "BEU". I have heard of a material called Rayon that might work but I am worried about wrecking my baffles during bundle insertion.
Any material suggestions would be great.

Thanks!

 

[btrueblood]

I think you may mean "Ryton", polyphenylene sulphide. Rayon is cellulose acetate, tends to melt at pretty low temperatures.

Only you know if the materials you choose are compatible with the fluids you intend to put into the HX (and you aren't telling us that, nor the temperature so how can we guess .

Another thing to consider is the difference in thermal expansion coefficients between the (presumably) steel tubes and the plastic baffles. The baffles may loosen up as the temperature of the material rises (plastics always out-expand metals); and even if it doesn't loosen immediately, it may do so after a number of thermal cycles. There are ways to design around that problem, but knowing what materials you need and the temperatures involved will impact that design.

 

[btrueblood]

Sorry, not to run on, but I didn't include one way I have made baffles with dissimilar materials work: use elastomeric bushings in the baffle holes, to seal, support, but allow for thermal expansion differences between the tube and baffles.

 

[coatingengineer]

Hi.

I have no experience in baffles. But I can tell you that PEEK (polyether-ether-ketone) has exceptional thermal stability.

Its glass transition temperature is 143 C (289 F). And, as a semi-crystalline thermoplastic, it retains most of its mechanical properties close to its melting temperature of 343 C (649 F).

Its Heat Deflection Temperature (HDT, ISO 75) can be superior to glass-filled versions of PAI (polyamide imide), PPS (polyphenylene sulfide), or PES (polyether sulfone).

For more information, see:
<a href="

http://www.industrialcoatingsworld....s/PEEK-Corrosion-Resistant-Coating.html">PEEK

Corrosion Resistant Coating</a>

Good luck!

William Gunnar

http://www.IndustrialCoatingsWorld.com

 

[finman]

I've built small Oil cooler stacks with Acetal baffles with no problems.

I've also used Nylon 66 for tubeplates for a hydraulic oil cooler, with the tube glued into the plate.

But you do need to check compatibilty and temperature limits with most non-metallic materials.