Actually none of the above.
It operates via a worm screw inside a stator. The stator is circular to fill the body of the pump and the worm revolves inside it, effectively an Archimedes screw.
I never used any other than clean honey in it, and for creaming honey + pumping honey in to the bottling machine.
I realise this may not help but it was a full blown commercial pump and for that matter still is. Cost me 6 barrels of OSR honey so not a toy version....memory says it took some 240lbs to fill a barrel so if bulk price now is £2 a pound...
I bought mine from a Bee Farmer who had used it for goodness knows how many tons and I used it for a good few more. How much life is left in it I have no idea but it wasn't leaking or exhibiting any issues before I stopped using it.
PH