There seems to be a lot of noise in the community regarding avoiding non-metal impellers on biodiesel processors. But the original GL design used a CH pump which had plastic impellers, and a lot a commercial processors use vane pumps which often have synthetic vane materials.
Mark is planning on using his multistager with PPO components on his rig. I've got a 100lpm pump with PPO impeller that will fit my rig so I'm also going to give it a whirl.
This one:
http://www.speroni.it/public/en/prodotto_dett.php?id=43Liquid temperature up to 60°C according to the website but datasheet says 90C - we will see
http://en.wikipedia.org/wiki/Noryl"Noryl is a blend of polyphenylene oxide (PPO) and polystyrene (PS) that was developed by General Electric Plastics in 1966"
"Noryl is stable in boiling water. The precise value of the transition depends on the exact composition of the grade being used. There is a smooth linear relation between weight content of polystyrene and the Tg of the blend."
Debating whether to stay under the 90C or take it up to 105C (they must allow some margin for manufacturing variance surely?) - if it survives this then good - if it fails then at least we'll have conclusive evidence. The pump came to me as a cheapy because it was seized - I don't mind sacrificing it in the name of experimentation.
I'm going to purchase a couple of extra 1" BSP to 28mm pipe adapters so the pumps can be swapped quickly in the case of failure.
Of course I'll take before and after photos of the impeller.
Wish me luck!
