Hmmm... I'm pretty sure Iwaki uses a fluid bearing to keep the rotor from contacting the shaft (or at least their sales material seems to claim this). No idea how well it works.
I have had some contact with fluid (AKA "plain") bearings in the automotive world. The shop owner (back when I worked at a bike shop) had a film from ...Chevrolet? anyway it was a high speed film of the various things oil would do inside of an engine. They had a part transparent plain bearing and you could see the shock wave the outer portion of the bearing was riding on.
Of course, that was engines and oil and this is pumps and water, but I would guess that it would be possible to design a bearing that worked a lot the same way and had been assuming (silly me - and, yes, I do know what you can do with that word) that at least the high end pumps would have been designed with something similar.
So now this mention of sapphire bearings has me thinking that it isn't possible to make plain bearings "work" in centrifugal water pumps.
Anyone care to enlighten me as to what important point(s) I've missed?
Is it as simple as "automotive hours are nothing compared to 24x7 x a couple of years? Something else?
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