There is no other way than the UF pump!
It's now a stepper motor with a known volume per stroke, so previously you'd see multiple strokes each equating to 1 ml of fluid removal, but now the pump can rotate the diaphragm in and out 10 times in a second if it needs to. This still gives the accuracy required and explains why you can't see much noticeable difference in duty cycle
or i'm talking crap!
Can't agree, never could! even if polite is my middle name . The balance flow is exactly that(what goes in comes out)
ergo the fluid provided at one side balances the other, no matter how hard P03 runs it can't remove any more than is put in from the clean side.
The only way to increase the volume removed on the effluent side is to created a deficit in volume into the balance flow on this side, therefore the UF pump bypasses what returns to the balance flow, hence the increase in TMP, hence the fluid drag across the membrane of the dialyser!
the UF pump rotates instead of pumping as such so;
to remove 20L = say 2 L fluid loss we have 22L in 4 hours
this equates to 5500ml/h or 91.66mls/min
the volume of a UF pump is around 1ml so we have 90 ish rotations/min
or 9 rotations every 6 seconds, I would imagine this only shows as 1 illumination of the pump on the diagnostic flow diagram.
Believe me it took some getting away from the traditional Uf pump removes a mill so it must drag that from across the dialyzer.
You almost need the extra corporeal circuit adding to the flow diagram to help visualize whats going on.
I've always taken it for granted that the UF pump did all the work.
Even now, this added knowledge won't hellp me fix it any easier!
To be honest I'd forgot that the sub port was post balance flow, this creates the deficit pre dialyser, and accuracy is irelivent from the sub port as its balenced.
Clever it is..