Best o ring material for marine heat exchanger 1

[MBam]

I am looking for a recommendation re the best O ring material to use in a marine heat exchanger.

The liquids are sea water and antifreeze (50% ethylene glycol/water). Normal temperature is 180F with 230F maximum.

The problem that currently exists is that the o rings take a set and start to seep. Once that happens the aluminum housing corrodes and damages the copper cooling bundle. At this time I don't know the assembled dimensions as the one housing I have is too corroded to measure. I will have another one later today.

I don't know what the existing material is however the manufacturer specifies a 24 month replacement interval. Given the amount of work involved in changing them out the actual cost of the o ring is probably not a factor.

Thanks!!

 

[btrueblood]

EPDM would be the material of choice for water and water with anything that dissolves in it. 70 durometer EPDM is fairly standard, set-resistant stuff. The peroxide-cured epdm's are a bit more set resistant, and cost a bit more.

Oh, just one thing - never let standard petroleum products (oil, grease, fuel) get on epdm, it will soften and swell. If you need a lubricant for installation, use silicone grease, or plain old soap and water, or water and glycol.

 

[MBam]

Thank you!

I'm getting ready to machine the damaged housing and put in a sleeve to restore the surface. I am trying to decide on aluminum or bronze. I am thinking bronze will be better.

See photo.

 

[MBam]

More photos

 

[sreid]

Hypalon

https://en.wikipedia.org/wiki/Hypalon

 

[MikeHalloran]

You may have other problems.
If you allow sea water to get hotter than ~140F, the salt will plate out on all metal surfaces, and eventually clog the pipes.
You may need bigger heat exchangers and higher seawater flows.




Mike Halloran
Stratford, CT, USA

 

[sreid]

UHMWPE

https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene