The distillate flow is intermittant. The distillate
with distillate and when the level gets too high,
a pump comes on to pump out a certain volume of distillate to
get the level back down.
A graph like this needs to be made with your results in Excel:
The green line shows what the
straight-line-between-each-data-point curve looks like.
The dotted red curve shows what is really going on.
For this graph, it says that the pump is pumping at a
setting of "1" between 0.33 and 0.67 minutes;
the pump is pumping at a setting of "2" between 0.67 and 1.0 minutes;
the pump is pumping at a setting of "3" between 1.00 and 1.33 minutes and
the pump is pumping at a setting of "4" between 1.33 and 1.67 minutes.
The total volume pumped for this profile was 66 ml of distillate.
If the pump peak setting is "5", the volume is 95 ml ± 3
If the pump peak setting is "4", the volume is 63 ml ± 6 ml
If the pump peak setting is "3", the volume is 35 ml ± 8 ml
If the pump peak setting is "2", the volume is 27.6 ml (uncertainty unknown)
Using this information and assuming that the pump operates
in a linear flow vs. setting,
you can calculate the volume of distillate over any period of your experiment.