Malvern MPT-2, User Manual, Page: 39 / 85

Software and Control Chapter 3
MPT-2 & Degasser Page 3-5
Dispenser Automatic/Manual - Select Automatic to let the software
control the pump and stirrer speeds, or specify an appropri-
ate speed for the sample using
Manual .
Pump speed - Sets the speed of the pump that recirculates
the sample through the flow cell. For normal operation this
will generally be between 30% and 80%.
Stirrer speed - Sets the stirrer speed. Care should be taken
not to introduce bubbles into the measurements by setting
the stirrer speed too high.
Recirculate between repeat measurements - If more than
one measurement is being made at one titration point then
this check box gives the option of either making all measure-
ments on the sample within the cell or recirculating the sam-
ple between measurements. This option is selectable for
Size measurements, but is always on when performing pH vs
Zeta potential measurements. This is to prevent the pH read-
ing from being affected when the Zeta voltage field is
applied.
Sample volume This is used to inform the software how much sample is ini-
tially added to the sample container. The more accurately
this volume is specified, the more precise the titration will be.
The initial start volume will vary according to the titration
type being performed; generally this will be between 3ml
minimum and 25ml maximum. When the magnetic stirrer is
used a minimum of 8ml is necessary for pH titrations, and
5ml for all others.
Filter This option should be enabled when running the Titrator with
a filter fitted. This is to ensure correct operation of the pump.
With the
Filter is fitted checkbox enabled, the pump reverse
action is disabled to avoid dislodging particles from the filter.
Extra pressure from reverse pumping when the filter is
attached may create leaks within the system.
Predicted
volume On the left of the Titrants dialogue a display is shown indi-
cating how full the sample container will get. This display
estimates the predicted total volume that will eventually end
up in the sample container (initial sample volume plus all the
titrant additions), to ensure that the container does not over-
flow and is full enough to cover the dispense tubes.
The display indicates by colour the volume and risk level of
any overflow.
Unless a dilution titration is being performed (see below) the
display will always show the 'standard' sample container.
Settings Description
MAN0318-4.0 - MPT-2 Autotitrator-Degasser.book Page 5 Tuesday, September 4, 2012 12:15 PM