Malvern MPT-2, User Manual, Page: 14 / 85

Chapter 1 Introduction and hardware
Page 1-8 MAN 0318

Sample exit and return tubes
The sample is pumped to and from the cell through these tubes. The ends of the
sample exit and return tubes must always be below the surface of the sample, for
two reasons:
1.
If the sample exit tube is above the level of the sample, no sample can be
pumped and circulated.
2.
Bubbles may be generated from the dropping of sample back into the sample
container.

Titrant tubes
The measured dose of titrant from the titrant containers enters the sample con-
tainer through these tubes. The ends of the titrant tubes must always be below the
surface of the sample, for two reasons:
1.
If small amounts of titrant are dispensed these may stay attached to the end of
the titrant tube. Immersing the tubes in the sample will break the surface ten-
sion.
2.
Bubbles may be generated from the dropping of titrant into the sample.
The titrant tubes are the same as those used for the sample. If required the titrant
tubes can be extended to use a larger volume titrant container. A cut-out is pro-
vided at the top of the dispersion area cover for the exit of the tubes.
Note
For protein measurements where only a minimum sample volume is
desired, loosen the tubing clamp and carefully pull both
sample and
titrant tubing down towards the bottom of the container - see the Tub-
ing connection bracket section later in this chapter. Ideally the stirrer is
not used. It is not required with protein measurements when the mini-
mum volume is required.

Status indicator
This indicator shows the status of the titrator. The indicator will show:

Red if the titrator has encountered an error condition.

Green if the titrator is in operation.

Amber if the titrator is in standby mode.
MAN0318-4.0 - MPT-2 Autotitrator-Degasser.book Page 8 Tuesday, September 4, 2012 12:15 PM